OSHA 30-Hour Course
Instructors Manual
Introduction to OSHA
Introduction
By the 1960s, the number and severity of occupational injuries and illnesses in the
United States were increasing. Disabling injuries grew 20 percent during that decade,
and 14,000 workers were dying on the job each year.
These rising workplace injury and death rates provoked a public outcry, in keeping
with the social activism of the decade, and forced the government to take action. On
December 29, 1970, President Richard M. Nixon signed The Occupational Safety and
Health Act of 1970. The OSH Act charged the Occupational Safety and Health
Administration with assuring safe and healthful conditions for working men and
women.
OSHA has focused its resources where they can have the greatest impact in reducing
injuries, illnesses, and deaths in the workplace. The mission of OSHA is to save lives,
prevent injuries, and protect the health of America's workers.
Since the agency was created in 1971, workplace fatalities have been cut in half and
occupational injury and illness rates have declined 40 percent. At the same time, U.S.
employment has nearly doubled from 56 million workers at 3.5 million worksites to
105 million workers at nearly 6.9 million sites.
Lesson Overview
Welcome to the "Introduction to OSHA" lesson of the Turner OSHA Certification
course. This lesson introduces OSHA (Occupational Safety and Health Administration),
a government agency within the Department of Labor. In this lesson, you will learn
about the history and mission of OSHA, the OSH Act, and the services provided by
OSHA. You will also learn more about OSHA standards and the general duties of
employers and employees.
Upon
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completing this lesson, you will be able to:
Describe the history and purposes of OSHA and the OSH Act
Summarize the services provided by OSHA
Describe the OSHA standard-development process and how to read the
standards
• State OSHA's General Duty Clause and list the general duties of employers and
employees
Why Learn This Lesson?
OSHA cannot succeed in its mission to protect American workers without fully
informed employers and employees. This lesson provides valuable insight into how
OSHA came about, its duties, and its products and programs. With the information
provided in this lesson, you can take better advantage of the services and programs
offered by OSHA to improve workplace safety and health.
Topic 1: OSHA Overview
The Need for the OSH Act
The United States was without a national safety and health policy at the start of the
20th century. As the workforce continued to grow and workers continued to be
injured or killed on the job, the human cost and the burden on the nation's commerce
became staggering in terms of lost production and wages, medical expenses, and
disability compensation.
As a result, sentiment grew among the general public and many in Congress for more
federal involvement in workplace safety and health issues. In 1970, Congress
considered the following statistics while deciding on a course of action:
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More than 14,000 workers killed in job-related accidents
More than 2.2 million workers suffering disabling injuries
More than 300,000 new cases of occupational diseases
A national policy was established on December 29, 1970, when the Williams-Steiger
Act, also known as the Occupational Safety and Health Act of 1970, was signed into
law by President Richard M. Nixon (Public Law N. 91-596) and took effect on April 29,
1971.
The ACT
The OSH Act established three permanent agencies:
• The Occupational Safety and Health Administration (OSHA) within the Labor
Department to set and enforce workplace safety and health standards
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The National Institute for Occupational Safety and Health (NIOSH) in what was
then the Department of Health, Education, and Welfare to conduct research on
occupational safety and health
The Occupational Safety and Health Review Commission (OSHRC), an
independent agency to adjudicate enforcement actions challenged by
employers
The general purpose of the OSH Act is
"...to assure so far as possible every working man and woman in the Nation safe and
healthful working conditions and to preserve our human resources."
THE ACT
"To assure safe and healthful working conditions for working men and
women; by authorizing enforcement of the standards developed under
the Act; by assisting and encouraging the States in their efforts to
assure safe and healthful working conditions; by providing for research,
information, education, and training in the field of occupational safety
and health; and for other purposes.
Be it enacted by the Senate and House of Representatives of the United
States of America in Congress assembled, That this Act may be cited as
the 'Occupational Safety and Health Act of 1970."
What does the OSH Act cover?
The Act covers all employers and their employees in the 50 states, the District of
Columbia, Puerto Rico, and all other territories under federal jurisdiction.
The Act applies to private sector employers and employees in virtually all fields
including manufacturing, construction, longshoring, agriculture, law and medicine,
charity and disaster relief, organized labor, and private education. Coverage is
provided by federal OSHA or through an OSHA-approved state program.
OSHA is divided into 10 regional offices and 67 area offices nationwide. See the color
map below.
Purposes of OSHA
The Act created the Occupational Safety and Health Administration (OSHA) to oversee
the federal standards for occupational safety and health. The mission of OSHA is to
save lives, prevent injuries, and protect the health of America's workers.
The following are the basic tasks performed by OSHA:
• Encourage employers and employees to reduce workplace hazards and
implement safety and health programs
• Provide for research in occupational safety and health in order to develop new
ways of dealing with occupational safety and health problems
• Maintain a reporting and recordkeeping system to monitor job-related injuries
and illnesses
• Establish training programs to increase the number and competence of
occupational safety and health personnel
• Develop mandatory job safety and health standards and enforce them
effectively
• Provide for the development, analysis, evaluation, and approval of state
occupational safety and health programs
Three Decades of OSHA
In the 1970s, OSHA's main task was to put an initial base of standards in place by
adopting existing, widely recognized, and accepted standards. During this period,
OSHA employed several enforcement strategies. Initially the agency emphasized
voluntary compliance with inspections dedicated to catastrophic accidents and the
most dangerous and unhealthful workplaces. In the late 1970s, OSHA further refined
its inspection targeting system to focus 95 percent of health inspections on industries
with the most serious problems.
In the 1980s, OSHA began to focus on minimizing regulatory burdens. The agency
relied more on computers to track its activities and provide accountability. Its goal
was to provide a balanced mix of enforcement, education and training, standardsetting, and consultation activities.
In the 1990s, OSHA re-examined its goals, looking for ways to leverage its resources
and increase its impact in reducing workplace injuries, illnesses, and deaths. The
"New OSHA" focused on reducing red tape, streamlining standard-setting, and
inspecting workplaces where employees were in greatest need of protection.
As the new century began, OSHA was broadening its outreach efforts, with new
compliance assistance specialists slated to join every area office to provide safety
seminars, training, and guidance to employers and employees upon request.
State Plans
The Act encourages states to develop and operate state job safety and health plans
under OSHA guidance. OSHA approves and monitors state plans.
Once a state plan is approved, the state is required to provide standards and
enforcement programs, as well as voluntary compliance activities that are at least as
effective as the federal program.
Employers and employees should find out if their state operates an OSHA-approved
state program. If so, they should become familiar with it (see a list of states with
their own occupational safety and health programs). State safety and health
standards under approved plans must keep pace with federal standards, and state
plans must guarantee employer and employee rights as does OSHA.
This map illustrates the state plan states and the federal regulated states.
Graphic/Animation
Topic Summary
Please take a moment to review these key points before you continue with the next
topic.
• On December 29, 1970, President Richard M. Nixon signed The Occupational
Safety and Health Act of 1970.
• The OSH Act established three permanent agencies: OSHA (Occupational
Safety and Health Administration), NIOSH (National Institute for Occupational
Safety and Health), and OSHRC (Occupational Safety and Health Review
Commission).
• The mission of OSHA is to save lives, prevent injuries, and protect the health of
America's workers.
Topic 2: OSHA Safety Services
Services
OSHA provides many services to promote safety and health in the workplace.
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OSHA Consultation: Consultation assistance is available to employers who
want help in establishing and maintaining a safe and healthful workplace. The
service is provided at no cost to the employer and, during the process, no
penalties are proposed or citations issued for hazards identified by the
consultant.
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Voluntary Protection Programs (VPP): The Voluntary Protection Programs
(VPP) represent one part of OSHA's effort to extend worker protection beyond
the minimum required by OSHA standards. These programs are cooperative
approaches which, when coupled with an effective enforcement program,
expand worker protection to help meet the goals of the OSH Act.
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OSHA Training Institute: The OSHA Training Institute (OTI) provides basic and
advanced training and education in safety and health for federal and state
compliance officers; state consultants; other federal agency personnel; and
private sector employers, employees, and their representatives.
In short, these programs assist employers in developing safety programs, provide
incentives, and educate safety and health personnel.
OSHA Consultation Assistance
Developed primarily for smaller employers with more hazardous operations, the
consultation service is usually delivered by state government agencies or universities
employing professional safety and health consultants.
When delivered at the worksite, consultation assistance includes these activities:
• An opening conference with the employer to explain the ground rules for
consultation
• A walk through the workplace to identify any specific hazards and examine
those aspects of the employer's safety and health program that relate to the
scope of the visit
• A closing conference followed by a written report to the employer of the
consultant's finding and recommendations.
Employers receiving a comprehensive consultation visit who then correct all identified
hazards and demonstrate that an effective safety and health program is in operation
may be exempted from OSHA programmed enforcement inspections (not complaint or
accident investigations) for a period of one year. If the employer fails or refuses to
eliminate or control worker exposure to any identified serious hazard or imminent
danger situation, OSHA may investigate and begin enforcement action.
Graphic/Animation
Voluntary Protection Programs (VPP)
The VPP concept recognizes that compliance enforcement alone can never fully
achieve the objectives of the OSH Act. Good safety management programs that go
beyond OSHA standards can protect workers more effectively than simple compliance.
There are three types of Voluntary Protection Programs:
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The Star Program is the most demanding and prestigious. It is open to an
employer in any industry who has successfully managed a comprehensive
safety and health program to reduce injury rates below the national average
for the industry.
The Merit Program is primarily a stepping-stone to Star program participation.
The Demonstration Program is for companies that provide Star-quality worker
protection in industries where certain Star requirements may not be
appropriate or effective.
Each of these programs is designed to recognize the outstanding achievements of
those who have successfully incorporated comprehensive safety and health programs
into their total management system. The program establishes a relationship between
employers, employees, and OSHA that is based on cooperation rather than coercion.
What are the requirements for Voluntary Protection
Programs?
Specific requirements for all of the Voluntary Protection Programs include each
of the following:
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Management commitment and employee participation
A quality worksite analysis program
Hazard prevention and control programs
Comprehensive safety and health training for all employees
These requirements must all be in place and operating effectively.
If a site is approved for VPP status, the employer receives a letter from the
Assistant Secretary informing the site of its participation. A certificate of
approval and flag are presented at a ceremony held at or near the approved
worksite. The VPP programs are available in states under federal jurisdiction;
however, some states have similar programs.
OSHA Training Institute
The OSHA Training Institute offers many courses covering areas such as electrical
hazards, machine guarding, ventilation, and ergonomics. More than 60 courses are
currently available for personnel in the private sector, dealing with subjects such as
safety and health in the construction industry and methods of voluntary compliance
with OSHA standards. OSHA also provides funds to nonprofit organizations to conduct
workplace training and education in subjects where OSHA identifies a need.
The Institute facility includes classrooms, laboratories, a library, and an audiovisual
unit. The OTI training laboratories contain various demonstrations and equipment,
such as power presses, woodworking and welding shops, a complete industrial
ventilation unit, and a sound demonstration laboratory.
In addition to the many resources at OTI, OSHA's area offices are full-service centers
offering a variety of informational services such as availability for speaking
engagements, publications, audiovisual aids on workplace hazards, and technical
advice.
Topic Summary
Please take a moment to review these key points before you continue with the next
topic.
OSHA provides three main services to promote safety and health in the workplace:
1) OSHA Consultation
2) Voluntary Protection Programs (VPP)
3) OSHA Training Institute.
Topic 3: OSHA Standards
This topic teaches what OSHA standards are, the development process for standards,
and how to read them. Upon completing this topic, you will be able to:
• Describe the process of setting up OSHA standards
• Decipher the system of references to OSHA standards
Vertical and Horizontal Standards
One of the primary responsibilities for OSHA under the Act is to develop workplace
safety and health standards. OSHA standards specify working conditions or practices
that employers and employees must adopt to ensure the appropriate level of safety
protection on the job.
There are two types of standards: vertical (specific industry) and horizontal
(universal) standards.
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Vertical standards are those that apply to a particular industry or particular
operations, practices, conditions, processes, means, methods, equipment, or
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installations. For example, Fall Protection Subpart M and Scaffolds Subpart L
are vertical standards.
Horizontal standards apply when a condition is not covered by a specific
industry. For example, Hazard Communication and Powered Industrial Trucks
are horizontal standards.
It is the responsibility of the employer to become familiar with the OSHA standards
that apply to their workplace. In addition, employees are required to comply with all
the rules and regulations that apply to the work they are to perform. You can find the
OSHA Standards in 29 CFR 1926.
The Standards-Setting Process
OSHA can initiate the development of workplace safety and health standards or the
Agency can act in response to petitions from other parties.
Once OSHA has developed plans to propose, amend, or revoke a standard, it
publishes these intentions in the Federal Register as a "Notice of Proposed
Rulemaking."
The Notice of Proposed Rulemaking will include the terms of the new rule and provide
a specific time (at least 30 days from the date of publication, and usually 60 days or
more) for the public to respond. It also may include dates for public hearings.
After the close of the comment period and any public hearings, OSHA must publish in
the Federal Register the full, final text of any standard amended or adopted and the
date it becomes effective, along with an explanation of the standard and the reasons
for implementing it. OSHA also may publish a determination that no standard or
amendment needs to be issued.
Who can initiate the development of new standards or changes to the existing
standards? OSHA can initiate the development of workplace safety and health
standards or the Agency can act in response to petitions from other parties.
These are some of the individuals or groups that may affect standard-setting:
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Secretary of Health and Human Services (HHS)
National Institute for Occupational Safety and Health (NIOSH)
U.S. Environmental Protection Agency (EPA)
State and local governments
Any nationally recognized standards-producing organization, employer,
or labor representative
Any interested party
The stages of development are:
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OSHA initiates the development of standards.
OSHA publishes the intentions of changes in the Federal Register as a "Notice
of Proposed Rulemaking."
The proposed standards go through public comment period and public
hearings.
OSHA publishes in the Federal Register the full, final text of any standard
amended or adopted and the date it becomes effective.
How to Read OSHA Standards?
Do you know how to read OSHA standards? The numbering system used in OSHA
standards can be confusing. It is often frustrating to find specific information you
need. Understanding the numbering system will help you locate relevant paragraphs
in OSHA standards more quickly.
All federal standards are referenced by codes. The code for OSHA standards is 29
CFR. CFR stands for Code of Federal Regulations and is different from Code of State
Regulations (CSR). In addition, each federal department or agency has its own
chapter of regulations. The chapter dedicated to OSHA is numbered 29. Whenever
you want to look up OSHA standards, look for the code 29 CFR first.
The chapter is broken down into parts. Different parts cover different industries. Part
1926 is Construction. Some other parts are 1910 for general industry, 1918 for
longshoring, and so on. Suppose you need to look up OSHA standards for the
construction industry; click the correct item in the Table of Content to continue.
The parts are usually broken down into subparts identified by capital letters, such as
subpart A-Z. These are subjective groupings to help you find information and are not
used as part of a cited reference. For example, Subpart F contains all standards
concerning Personal Protective and Life Saving Equipment. Subpart M contains all
standards concerning Fall Protection.
Technically, each part is broken down into sections and given a decimal number for
identification. The sections run consecutively throughout the part, with gaps left for
later additions. As you can see, relevant sections are grouped together under the
same subpart.
Now, let's try it out. Suppose you were asked to look up information under
29CFR.1925.150(c)(1)(iii).
Again, you need to look up information under 29CFR.1925.150(c)(1)(iii).
Show the book being turned to the section.
Once you locate the specific section of OSHA standards, you can follow the numbering
system to locate specific information contained in that section. Let's look at the
example: 29CFR.1925.150(c)(1)(iii).
Point and highlight the segment number and name discussed in the following text.
Each section is broken down into smaller segments. These segments are referenced
by small letters in parentheses. Each segment represents a topic within the section.
For example, the third topic is Portable Firefighting Equipment and is referenced by
(c).
Point and highlight the segment number and name discussed in the following text.
These segments/topics are broken down into smaller pieces, usually paragraphs. They
represent subtopics within the topic. These smaller pieces are referenced by numbers
in parentheses. For example, underneath 29CFR.1925.150(c) (the third topic within
the Fire 1926.150 section) there are two subtopics: 29CFR.1925.150(c)(1) is Fire
Extinguishers and Small Hose Lines and 29CFR.1925.150(c)(2) is Fire Hose and
Connections.
Point and highlight the segment number and name discussed in the following text.
These subtopics can be further broken down into smaller pieces when there are
several points within the subtopics. Each point will be a paragraph too. These points
are referenced by small Roman numerals in parentheses. The example
29CFR.1925.150(c)(1)(iii) refers to the third point underneath 1925.150(c)(1).
The points can be broken down further into lower levels. In short, this is how the
OSHA standards flow. As long as you know how to locate the specific sections of
OSHA standards, you should be able to find relevant information easily.
Topic Summary
Please take a moment to review these major points before you continue with the next
topic:
• One of OSHA's primary responsibilities under the Act is to develop workplace
safety and health standards.
• A rigid process governs the development of standards.
• All federal standards use a numbering system. OSHA standards relevant to the
construction industry are under the 29 CFR 1926 section.
Topic 4: General Duties
This topic adresses the general duties of employers and employees. Upon completing
this topic, you should be able to:
• List the general duties of employers
• List the general duties of employees
General Duty Clause
In the event that OSHA does not have specific standards to address a workplace
hazard, employers are responsible for following the Act's General Duty Clause, a
provision within the OSH Act.
The General Duty Clause allows OSHA to cite employers even if there is no specific
standard the employer violated.
The following elements are necessary for a General Duty Clause violation to exist:
• The employer failed to keep the workplace free of hazards to which employees
were exposed.
• The hazard was recognized.
• The hazard was causing or was likely to cause death or serious harm.
• There was a feasible and useful method for correcting the hazard.
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An employer who is in compliance with any standard in this part shall be deemed to
be in compliance with the General Duty Clause 5(a)(1) of the Act.
Graphic/Animation
The General Duty Clause of the Act states the each employer
"shall furnish...a place of employment free from recognized hazards that are causing
or are likely to cause death or serious physical harm to his/her employees."
Rights and Responsibilities
The OSH Act establishes general rights and responsibilities of both employers and
employees in the workplaces of this nation.
These
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are the rights and responsibilities of employers:
Comment on standards during their formulation.
Apply for a temporary or permanent variance.
Be present during an inspection.
File a Notice of Contest.
Have confidentiality of trade secrets.
Obtain assistance from OSHA with compliance.
These
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are the rights and responsibilities of employees
Work in a safe work environment.
Complain to OSHA without fear of punishment or discrimination.
Comment on standards during their formulation.
Review OSHA injury/illness summaries, personal medical records, or
monitoring records.
Be informed of a variance.
Review OSHA citations.
Have an employer representative present during an OSHA inspection.
Observe monitoring or measurement of toxic substances.
Topic Summary
Please take a moment to review these major points before you continue with the next
topic.
• The OSH Act establishes general rights and responsibilities for both employers
and employees in the workplaces of this nation.
• The employers' general duties are to become familiar with the OSHA standards
that apply to their workplace and comply with those standards.
• The employees' general duties are to comply with all the rules and regulations
that apply to the work they perform.
Lesson Summary
This lesson contains information and instruction about OSHA. By completing this
lesson, you should have the knowledge to discuss the following topics. Take a
moment to see if you can do the following:
• Describe the history and purposes of OSHA and the OSH Act
• Summarize the services provided by OSHA
• Describe the OSHA standard-development process and how to find the
standards
• State OSHA's General Duty Clause and list the general duties of employers and
employees
General Safety Provisions
Introduction
OSHA strives to "assure safe and healthful working conditions for working men
and women..." and mandates that "each employer shall furnish to each of his
employees employment and a place of employment which are free from
recognized hazards that are causing or are likely to cause death or serious
physical harm to his employees." OSHA further states, "no contractor can
require any worker to perform contract work in conditions that are unsanitary,
hazardous, or dangerous to their health and safety."
In order to ensure this, OSHA has determined that each employer must set up
a program to manage workplace safety and health. The goal of any safety and
health program is to reduce injuries, illnesses and fatalities, while achieving
compliance with OSHA standards and the General Duty Clause. The program
must be appropriate to conditions in the workplace, such as the types of
hazards present and the number of employees on the jobsite.
The best safety and health programs involve every level of the organization,
instilling a safety culture that reduces accidents and improves the bottom line.
In fact, according to OSHA an effective safety and health program forms the
basis of good worker protection and can save time and money-about $4 for
every dollar spent-and increase productivity.
When safety and health are a part of the organization and a way of life,
everyone wins.
Lesson Overview
The goal of any safety and health program is to reduce injuries, illnesses, and
fatalities while achieving compliance with OSHA standards and the General
Duty Clause.
This lesson covers many of OSHA's "building block" standards and some of the
basic safety provisions that apply to all construction worksites. Upon
completing this lesson, you will be able to:
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Describe why safety program is important and state competent and
qualified person
Summarize elements of a safety and health program
Explain OSHA's basic safety standards
Why Learn This Lesson?
This lesson is important because it covers the most basic "building block"
standard, safety and health programs, as well as other basic provisions of
Subpart C.
Subpart C contains the basic requirements of a safety and health program.
These requirements are referenced throughout all of the construction
standards. Standards such as "...frequent and regular inspections of the job
sites...by competent persons..." are referenced in several other standards
including excavations, fall protection, and stairways and ladders.
Other general requirements covering topics such as first aid and housekeeping
at the site, and sanitation are at the foundation of jobsite safety.
Effective management of worker safety and health protection is a decisive
factor in reducing the extent and severity of work-related injuries and illnesses
and related costs and it all begins with the information covered in this lesson.
Topic 1: Overview
In this topic you will learn why a safety program is important and
competent/qualified person. Upon completing this topic you will be able to:
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Describe why a safety program is important
State competent person and qualified person
Why Is A Safety Program Important?
The formal safety program is a set of written documents that describe a
company's safety policies, priorities, and responsibilities. Just because a safety
program is written, it doesn't mean it is always followed. To be effective,
everyone on the management team must understand what is expected of him
or her and safety must be an ongoing, essential part of production. This
means the entire workforce must have an occasional reminder of what
accident prevention is all about.
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Workers: You as workers need to know what is specifically required of
you in order to perform your job safely.
Supervisors: You as supervisors need the tools and guidance to help you
manage a safe construction process.
Management: Management must continually protect the greatest asset-the workforce
Safety is a Teamwork Effort.
Competent Person/Qualified Person
The term "competent person" and to a lesser degree at this time, the term
"qualified person" is emerging rapidly in federal safety regulations (OSHA)
regarding the construction industry. OSHA broadly defines each in the
standards for construction.
"Competent person" means one who is capable of identifying existing and
predictable hazards in the surroundings or working conditions which are
unsanitary, hazardous, or dangerous to employees, and who has authorization
to take prompt corrective measures to eliminate them.
It is the responsibility of the employer to provide frequent and regular
inspections of the jobsite, materials, and equipment for possible hazards. The
employer will determine and designate a competent person to conduct these
inspections.
"Qualified person" means one who, by possession of a recognized degree,
certificate, or professional standing, or by extensive knowledge, training, and
experience, has successfully demonstrated his/her ability to solve or resolve
problems relating to the subject matter, the work, or the project.
Key Point: The difference between a "competent" person and a
"qualified" person lies in the "authority" granted to the "competent"
person to take action to correct or eliminate hazards.
What are the OSHA construction standards that require competent persons?
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Accident Prevention
Responsibility
Ionizing Radiation
Asbestos
Hearing Protection
Welding and cutting
Respiratory Protection
Scaffolding
Slings
Cranes and derricks
Electrical
Material/personnel hoists and elevators
Fall protection
Excavations and trenching
Concrete, Concrete forms and shoring
Requirements for lift slab operations
Tunnels and shafts, caissons, cofferdams and compressed air
Bolting, riveting, fitting up and planking up
Underground construction
Demolition -Preparatory operations
Compressed air
Lead
Mechanical demolition
Ladders
Note: You must also have a competent person on site to qualify for OSHA's
focused inspection process.
Management leadership
• Identifies jobs requiring competent persons
• Identifies requirements needed by competent person
• Provides necessary training
• Ensures competent person understands duties
• Holds competent person accountable
• Provides all necessary equipment/materials
• Provides written standards for review audits for results
Competent person guide
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Competent person
Competent person
Competent person
Competent person
Competent person
Competent person
procedures
Competent person
understands duties and responsibilities
has training
has knowledge and skill to assume task
is familiar with duties and standards
given authority to function on the job
provided with and reviews applicable standards
provided with necessary equipment/materials
Topic Summary
Please take a moment to review these points before you continue with the
next topic.
• The goal of any safety and health program is to reduce in injuries,
illnesses, and fatalities while achieving compliance with OSHA standards
and the General Duty Clause
• Safety is a teamwork effort among workers, supervisors, and
management.
• The difference between a "competent" person and a "qualified" person
lies in the "authority" granted to the "competent" person to take action
to correct or eliminate hazards.
Topic 2: Elements of a Safety and Health Program
A successful safety and health program starts with basic requirements and
incorporates every operation on the job. According to OSHA, a safety and
health program should have the following core elements:
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Management leadership
Employee participation
Hazard identification and assessment
Hazard prevention and control
Information and training
Evaluation of program effectiveness
Upon completing this topic you will be able to summarize each element of a
safety and health program.
Management Leadership
Management demonstrates leadership by providing the resources, motivation,
priorities, and accountability for ensuring the safety and health of its
workforce.
This leadership involves setting up systems to ensure continuous improvement
and maintaining a health and safety focus while attending to production
concerns. Effective managers understand the value in creating and fostering a
strong safety culture within their organization. Safety should become elevated
so that it is a value of the organization as opposed to something that you
"have to" accomplish.
Integrating safety and health concerns into the everyday management of the
organization, just like production, quality control, and marketing allows for a
proactive approach to accident prevention and demonstrates the importance of
working safety into the entire organization.
The employer must develop a safety policy. This is usually a simple but
important statement, emphasizing that the safety and well being of employees
is of the highest priority in the firm, and will be fully supported by top
management.
A list of specific Safe Work Practices must also be established for the safety of
each individual and all co-workers. These "conditions of employment" can
prevent accidents during construction. However workers and companies often
tend to forget them, unless they are enforced.
Any good safety program will also include a disciplinary policy. When any
individual fails to follow established safety rules, the entire work team may be
at risk. When many people ignore the rules, the idea of consistent safe work
practices vanishes. The disciplinary policy defines how safety rules will be
enforced fairly and consistently.
Employee Participation
The best worker safety and health protection occurs when everyone at the
worksite shares responsibility for protection. Basic principles of excellence
have shown that wise employers use employees' unique knowledge to help
find problems and resolve them. In addition, no one else has as much at stake
to avoid accidents as the employees who are likely to be injured.
When employees are involved in a variety of safety-related activities it is more
likely that they will:
•
•
•
Appreciate the potential hazards that exist on the jobsite
Avoid unsafe behaviors
Buy in to the overall safety culture of the organization
Without employees' participation and cooperation, accidents are difficult to
prevent. Safety responsibilities at every level of the organization must be
clearly defined in writing and in training, so everyone has a fair and equal
chance to live up to what is expected of them.
Hazard Identification and Assessment
There are two types of tools: worksite analysis and job safety/hazard analysis
that you can use in identifying and assessing hazard.
Worksite Analysis
It is important to know the potential hazards generally associated with
construction work as well as specific working conditions. If employees are to
be protected from workplace hazards, those hazards must be identified first. A
means of systematically identifying workplace hazards is needed so that the
hazards can be eliminated before accidents occur.
What is a Job Hazard Analysis?
The Job Hazard Analysis, or JHA, as it is commonly referred, is a method of
reviewing the individual steps in performing a job/task and identifying the
associated occupational safety and health hazards. This process is followed by
the development of solutions for each hazard that either eliminate or control
the employee's exposure to the hazard.
The JHA is very similar to a safety inspection, in that both are intended to
identify hazards and provide solutions to problems. Yet, while a safety
inspection is concerned with the entire operation, the JHA is focused on
covering a specific task in detail. Another difference is the regularity of each. A
safety inspection could occur on a daily/weekly/monthly basis, but the JHA is a
more stable procedure for performing a task. They are related to each other in
the respect that the safety inspection should be a check that the procedures
outlined by the JHA are:
•
•
Being practiced properly
Effectively eliminating or minimizing the hazard(s) they were intended to
address.
The proper use of the JHA will have a number of benefits for the company:
• The number of injuries will be reduced by the development of safe
operating procedures that will become routine for employees.
• By conducting JHAs and using them, the supervisors will learn more
about the jobs the employees perform and how to better manage them.
• When they are performed on a regular basis, JHAs will help to keep
employees aware of working safely and reporting unsafe conditions
when they arise.
The JHA helps employees to believe that safety is an integral part of the work,
rather than something extra that they should only think about when they have
time. Reviewing the JHA hazards with the employee performing the job will
help ensure an accurate and complete list. It also is a good way to educate
employees on the risks and gets their buy-in on any needed changes. Written
standard operating procedures can evolve through this process.
Obviously, a JHA should be conducted first for jobs with the highest rates of
accidents and disabling injuries. Also, jobs where "near misses" have occurred
should be given priority. The next priority is analyses of new jobs and jobs
where changes have been made. Eventually, a JHA should be conducted and
made available to employees for all jobs in the workplace.
If an accident or injury occurs on a specific job, the JHA should be reviewed
immediately to determine whether changes are needed in the job procedure.
The JHA will provide the employer with a reference document that can help to
determine the cause of the accident. The person conducting the accident
investigation can simply go over the JHA step-by-step with the affected
employee and/or witnesses and determine which step was missed or
performed incorrectly. The JHA should be considered a checklist for accident
investigations. Anytime a JHA is revised, training should be provided in the
new job methods or protective measures. You can also use a JHA to train new
employees.
Conducting A Job Hazard Analysis
There are four basic steps to conducting a Job Hazard Analysis:
1. Selecting the task to be analyzed.
2. Breaking the task down into each of its individual steps.
3. Identifying the hazard(s) that are associated with each step.
4. Developing safe operating procedures to eliminate or control the
hazards.
Selecting the Task: The first, and most important step in conducting a
JHA is to properly identify a specific task that can be analyzed. In order
to conduct a JHA, you cannot be too broad in defining a task. Providing a
general job description, such as welding, is not specific enough. This
employee may only have two or three tasks that are repeated over and
over, but for each one an individual JHA should be conducted.
In addition, the tasks cannot be too narrowly defined. For example,
pushing a button, or placing a piece of metal in a machine are not broad
enough. Each of these would be considered one step in a task, but not
separate tasks themselves. To be considered for a JHA, each "task" must
have a series of separate, definable, but related steps that accomplish a
specific goal.
You should begin with the tasks that have the greatest frequency of
accidents or injuries associated with them. By conducting JHAs on these
tasks first, you can reduce the number of accidents and injuries more
quickly. Once you have analyzed all of the existing tasks, you should
begin to work on new tasks that are just being created, tasks that are
being changed, and tasks that, even though they have already been
analyzed, have still been causing accidents and injuries.
Break the Task Into Steps: In the process of breaking the specific task
into its "steps," you must exercise caution to not be too general or too
detailed. By breaking the task down to 5-10 steps, you should be able to
get the most out of the JHA. Identifying only 2-3 steps will make it
difficult to indicate specific hazards. Also, dividing the task into 15-20
steps will make it difficult to associate specific hazards because they will
be spread out over a number of steps.
Once you have completed the identification of the "steps" to the "task,"
you should check with the employee whose task you are analyzing to
ensure accuracy. This can even be done prior to you doing any work. If
you first ask an employee to identify the steps of their work, then
observe the task to see if you agree, the process can be made much
simpler and very effective.
Identify the Hazards: When conducting a JHA, there are three basic
sources of information to be used: accident investigation reports, your
knowledge of safety and the workplace, and the employees performing
the tasks. You should analyze all accident investigation reports
associated with the task on which you are conducting a JHA and list the
hazards that have been associated with that task in the past.
The next step is to determine what possible problems may exist in
performing each task. Ask yourself the following questions: What could
happen to the employee? Do slip, trip, or fall hazards exist? Are their
strain or sprain hazards associated with the task? What other problems
or hazards may exist?
Next, you should involve the employees. They are usually the best
source of information since they perform the tasks on a daily basis.
Develop Safe Operating Procedures: You have many options available
for this part of the process, but, whichever method you choose, the goal
remains the same -eliminate or minimize the hazard from the task to be
completed. Some of the options may be to develop new procedures,
implement engineering controls, administrative controls such as limiting
exposure time, or the use of personal protective equipment.
It is not uncommon that in the search to find a safer way to perform a
task, you may also find a more efficient way to do the task.
Hazard Prevention and Control
The goal of a hazard prevention and control program is to make the workplace
as foolproof as possible. This is an ongoing process. You will design,
implement, revise, and improve preventive measures and controls as the
worksite changes and as you collect information about hazards.
Engineering Controls
Engineering controls, which attempt to eliminate hazards, do not necessarily
require that an engineer design the control. Engineering controls can be very
simple.
To the extent feasible, the work environment and the job itself should be
designed to eliminate or reduce exposure to hazards based on the following
principles:
• If feasible, design the jobsite, equipment, or process to remove the
hazard or substitute something that is not hazardous or is less
hazardous.
• If removal is not feasible, enclose the hazard to prevent exposure in
normal operations.
• Where complete enclosure is not feasible, establish barriers to reduce
exposure to the hazard in normal operations.
Administrative Controls
Administrative controls include lengthened rest breaks, additional relief
workers, exercise breaks to vary body motions, and rotating workers through
different jobs to reduce stress or repetitive motions on one part of the body.
They are normally used in conjunction with other controls that more directly
prevent or control exposure to hazards.
Personal Protective Equipment
When exposure to hazards cannot be engineered completely out of normal
operations or maintenance work, and when safe work practices cannot provide
sufficient additional protection, a further method of control is using personal
protective equipment or clothing. These include face shields, steel-toed shoes,
hard hats, respirators, hearing protection, gloves, and safety glasses.
Specific Written Programs
Federal and State laws also require that critical jobsite hazards must be
controlled through specific written programs and extra employee training.
These include programs in Confined Space Entry, Lock out /Tag out, Fall
Protection, Scaffolding Safety, Hazardous Materials, etc. Strict procedures are
necessary to prevent exposures, fatalities or serious injuries. You must follow
the strict procedures.
Accident/Incident Investigations
Accident/incident investigations are a tool for uncovering hazards that either
were missed earlier or have managed to slip out of the controls planned for
them, thus prevent future occurrences. All incidents, whether a near miss or
an actual injury-related event, should be investigated. Near miss reporting and
investigation allow you to identify and control hazards before they cause a
more serious incident. Accident/incident investigations are useful only when
done with the aim of discovering every contributing factor to the
accident/incident to "foolproof" the condition.
Safety Training
Training can help employees develop the knowledge and skills they need to
understand workplace hazards. OSHA considers safety and health training vital
to every workplace.
•
New employees: need training not only to do the job, but also to
recognize, understand, and avoid potential hazards to themselves and
others in their immediate work area and elsewhere in the workplace
•
Contract workers: need training to recognize your workplace's hazards
or potential hazards
•
Experienced workers: need training if new equipment is installed or
process changes
•
Employees needing to wear personal protective equipment and persons
working in high-risk situations: need special training
•
Employees or contract workers in worksites needing complex work
practices to control hazards and experiencing more frequent
occupational injuries and illnesses: need periodic safety and health
training to refresh their memories and to learn new methods of control.
Note: New training also may be necessary when OSHA or industry standards
require it or new standards are issued.
One-on-one training is possibly the most effective training method. The
supervisor periodically spends some time watching an individual employee
work. Then the supervisor meets with the employee to discuss safe work
practices, give credit for safe work, and provide additional instruction to
counteract any observed unsafe practices.
What are the Common Types of Specialized Training?
Safety and Health Training for Managers - Training managers in their
responsibilities is necessary to ensure their continuing support and
understanding. It is their responsibility to communicate the program's goal
and objectives to their employees, as well as assign safety and health
responsibilities, and hold subordinates accountable.
Safety and Health Training for Supervisors - Supervisors may need additional
training in hazard detection, accident investigation, their role in ensuring
maintenance of controls, emergency handling, and use of personal protective
equipment.
Job Orientation - The format and extent of orientation training will depend on
the complexity of hazards and the work practices needed to control them. An
orientation may consist of a quick review of site safety and health rules,
hazard communication training, and a run-through of job tasks. Larger
workplaces with more complex hazards and work practices to control them,
may wish to start with a clear description of hazards, followed by a discussion
of how to protect oneself. Employees may have on-the-job training and may
shadow an experienced employee for a period of time.
Specific OSHA Training - The employer must instruct each employee in the
recognition and avoidance of unsafe conditions and the regulations applicable
to his work environment to control or eliminate any hazards or other exposure
to illness or injury. Many OSHA standards contain specific training
requirements that will be covered in other lessons.
Safety Meetings - Responsibilities and safety procedures are rarely followed by
everyone without an occasional reminder. Most worksites have a variety of
hazards to discuss, and safety meetings provide this opportunity. Many
hazardous industries hold them weekly. Remember, though, you do not need
to wait for a safety meeting to correct a potentially hazardous situation.
Evaluation of Program Effectiveness
Initiating an audit trail for evaluating a safety and health program(s) is a way
to test the effectiveness of written or informal programs. Depending on the
amount of resources and time you want to devote, the process can be as
simple as taking several of the incidents listed on a company's annual OSHA
200 (annual summary of occupational injuries and illnesses) and tracking back
through applicable company reports or programs. This approach will allow you
to determine whether an effective safety and health program has been
implemented.
The checklist follows OSHA guidelines for establishing a safety and health
program. Each of these program elements should be present in establishing a
safety and health program:
Management Commitment and Leadership
• Policy statement: goals established, issued, and communicated
• Program revised annually
• Participation in safety meetings, inspections, and agenda items in
meetings
• Commitment of resources is adequate
• Safety rules and procedures incorporated into site operations
• Management observes safety rules
Assignment of Responsibility
• Safety designee on site, knowledgeable, and accountable
• Supervisors (including foremen) safety and health responsibilities
understood
• Employees adhere to safety rules
Identification and Control of Hazards
• Periodic site safety inspection program involves supervisors
• Preventative controls in place (PPE, maintenance, engineering
• Action taken to address hazards
• Safety Committee, where appropriate
• Technical references available
• Enforcement procedures by management
Training and Education
• Supervisors receive basic training
•
•
Specialized training taken when needed
Employee training program exists, is ongoing, and is effective
Recordkeeping and Hazard Analysis
• Records maintained of employee illnesses, injuries, and posted
• Supervisors perform accident investigations, determine causes, and
propose corrective action
• Injuries, near misses, and illnesses are evaluated for trends, similar
causes; corrective action initiated
First
•
•
•
Aid and Medical Assistance
First aid supplies and medical service available
Employees informed of medical results
Emergency procedures and training where necessary
Topic Summary
Please take a moment to review these points before you continue with the
next topic.According to OSHA, a safety and health program should have the
following core elements:
• Management leadership - Management demonstrates leadership by
providing the resources, motivation, priorities, and accountability for
ensuring the safety and health of its workforce.
• Employee participation - Without employees' participation and
cooperation, accidents are difficult to prevent.
• Hazard identification and assessment - There are two types of tools:
worksite analysis and job hazard analysis to identify and assess hazard.
• Hazard prevention and control - This includes engineering control,
administrative controls, personal protective equipment, specific written
programs, and accident/incident investigations.
• Information and training - Training can help employees develop the
knowledge and skills they need to understand workplace hazards. OSHA
considers safety and health training vital to every workplace
• Evaluation of program effectiveness - Initiating an audit trail for
evaluating a safety and health program(s) is a way to test the
effectiveness of written or informal programs.
Topic 3: Basic Safety Standards
In this topic you will learn basic safety standards regulated by OSHA. Upon
completing this topic you will be able to explain the following safety standards:
•
•
•
•
•
•
•
First Aid
Housekeeping
Illumination
Sanitation
Means of Egress
Emergency Action Plans
Access to Medical Records
First Aid
In the workplace it is often the job of a Certified First Aid Provider to assist in
stablizing an injured or ill person until professional medical help arrives.
Certified First Aid Providers are persons who are certified and trained to
certain levels in first aid and CPR (Cardiopulmonary Resuscitation).
OSHA states, "In the absence of an infirmary, clinic or hospital in the
near proximity of the workplace which is used for the treatment of all
injured employees, a person or persons shall be adequately trained to
render first aid. First aid supplies approved by the consulting physician
shall be readily available."
First aid services and provisions for medical care need to be made available by
the employer for every employee on the jobsite.
Note: The specific requirements for first aid, medical attention, and emergency
facilities are contained in Subpart D of the OSHA standards and will be covered
in the Health Hazards and Controls lesson.
Housekeeping
Housekeeping is a very important part of your job. It improves the overall
appearance of your work area. Here are some reasons to keep your work area
clean:
1. To reduce trip and fall hazards.
2. To increase production. You won't have to waste time looking for a
misplaced tool. You will always know where your tools are when you put
them where they belong after you use them.
3. To reduce a potential fire hazard by removing unneeded combustibles
from the work area.
OSHA has the following requirements for housekeeping:
• Form and scrap lumber with protruding nails, and all other debris, must
be kept cleared from work areas, passageways, and stairs, in and
around buildings or other structures.
• Combustible scrap and debris must be removed at regular intervals
during the course of construction.
• Containers must be provided for the collection and separation of waste,
trash, oily and used rags, and other refuse.
• Containers used for garbage and other oily, flammable, or hazardous
wastes, such as caustics, acids, harmful dusts, etc. must be equipped
with covers.
• Garbage and other waste must be disposed of at frequent and regular
intervals.
Tips to Maintain a Clean Work Area
• Plan the job. Make a list of the needed tools/materials. This will help to
minimize unnecessary clutter around your work area.
• Develop a routine for cleaning up at the end of the shift or periodically
during the shift.
• Do not allow employees to eat, drink or smoke in the work area, not
only because of litter problems, but also because of hygiene concerns.
Here are some results of poor housekeeping practices:
• Injuries, when employees trip, fall, strike or are struck by out-of-place
objects;
• Injuries from using improper tools because the correct tool can't be
found;
• Lowered production because of the time spent maneuvering over and
around someone else's mess, and time spent looking for proper tools
and materials;
•
Time spent investigating and reporting accidents that could have been
avoided
Illumination
OSHA requires that the following areas on a construction site be lighted, either
naturally or by using illumination devices:
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Aisles
Stairs
Ramps
Runways
Corridors
Offices
Shops
Storage areas
The minimum illumination requirements for work areas are contained in OSHA
Subpart D and will be covered in the Health Hazards and Controls lesson.
Sanitation
Drinking Water
On the jobsite, portable containers that are used to dispense drinking water
have to be tightly closed and equipped with a tap. The container used to
distribute drinking water shall be clearly marked as to the nature of its
contents and not used for any other purpose.
Drinking water cannot be set up so that it must be dipped from containers.
The use of a common drinking cup on the jobsite is prohibited.
Where single service cups (to be used but once) are supplied, both a sanitary
container for the unused cups and a receptacle for disposing of the used cups
must be provided.
"Potable water" means water that meets the quality standards prescribed in
the U.S. Public Health Service Drinking Water Standards (link), published in 42
CFR part 72, or water that is approved for drinking purposes by the State or
local authority having jurisdiction.
Other Sources of Water
Outlets for nonpotable water, such as water for used for industrial or
firefighting purposes only, must be identified by signs, to indicate clearly that
the water is unsafe and is not to be used for drinking, washing, or cooking
purposes.
Toilet Facilities
Toilets have to be provided for employees according to the following table:
Number of Employees
Less than 20
20-200
More than 200
Number of Toilets
1
1 toilet seat and 1 urinal
per 40 workers
1 toilet seat and 1 urinal
per 50 workers
Note: These requirements do not apply to mobile crews that have
transportation readily available that will allow them to get to nearby toilet
facilities.
Washing Facilities
On every construction site there should be adequate washing facilities for
employees who work with paints, coatings, herbicides, or insecticides, or in
other operations where they are exposed to harmful contaminants. The
washing facilities should be near the jobsite, be properly equipped for
employees to be able to remove these types of substances, and maintained in
a sanitary condition.
Sanitation Checklist
• Toilets and washing facilities are clean and sanitary
• Toilets are designed to ensure user privacy, and are supplied with toilet
paper
• Sufficient toilets and washing facilities are available
• Adequate supplies of potable water are available
• Drinking water is stored and dispensed in clearly marked containers that
are not used for any other purpose
• Drinking water is dispensed from fountains, or single service cups are
supplied
•
•
All pipes and containers for non-potable water have been clearly labeled,
and only potable water is used for washing, drinking, or cooking
Change rooms (if required) are clean without accumulated dirty clothes,
food, or food containers.
Means of Egress
OSHA requires that every building or structure must have exits that are free
from obstruction at all times when it is occupied. There cannot be any lock or
fastening device attached that would prevent workers from using any means
of egress.
In addition, the exits must be marked with a sign that is visible to the
occupants.
Emergency Action Plans
Emergency action plans that are required by any particular OSHA standard,
such as fire protection, must meet the following requirements. The emergency
action plan has to be in writing (except for employers with 10 or fewer
employees). It must cover the designated actions employers and employees
have to take in order to ensure employee safety from fire and other
emergencies.
The following elements, at a minimum, must be included in the plan:
• Emergency escape procedures and emergency escape route
assignments;
• Procedures to be followed by employees who remain to operate critical
plant operations before they evacuate;
• Procedures to account for all employees after emergency evacuation has
been completed;
• Rescue and medical duties for those employees who are to perform
them;
• An employee alarm system;
• The method of evacuation to be used in emergency circumstances.
• The preferred means of reporting fires and other emergencies; and
• Names or regular job titles of persons or departments who can be
contacted for further information or explanation of duties under the plan.
Before implementing the emergency action plan, the employer must designate
and train a sufficient number of employees to assist in the safe and orderly
emergency evacuation of employees.
The employer must review the plan with each employee covered by the plan at
the following times:
• Initially when the plan is developed,
• Whenever the employee's responsibilities or designated actions under
the plan change, and
• Whenever the plan is changed.
Access to Medical Records
Employers in the construction industry must provide records access to all
employees exposed to toxic substances and harmful physical agents, their
employee representatives, health professionals, and OSHA. The rule does not
require creation of any records, only preservation.
The employer must provide the requested records promptly, generally within
15 working days. Requests for these records do not have to be in writing
except where trade secrets are involved. Union and health professionals must
have specific written consent to gain access to employees' personal medical
records but may examine exposure records without such consent but they
must state the specific record needed and the occupational health need for
gaining access to the information.
Topic Summary
Please take a moment to review these points before you continue with the
next topic. OSHA regulated the following basic safety standards:
• First Aid - First aid services and provisions for medical care need to be
made available by the employer for every employee on the jobsite.
• Housekeeping - OSAH has requirements for housekeeping. (pop-up)
•
•
•
•
•
Illumination - OSHA requires that certain areas (pop up) on a
construction site be lighted, either naturally or by using illumination
devices
Sanitation - OSAH has requirements for drinking water, other sources of
water, toilet facilities, and washing facilities.
Means of Egress - OSHA requires that every building or structure must
have exits that are free from obstruction at all times when it is occupied.
Emergency Action Plans Access to Medical Records - Employers in the construction industry must
provide records access to all employees exposed to toxic substances and
harmful physical agents, their employee representatives, health
professionals, and OSHA.
Lesson Summary
This lesson contains information and instruction about General Safety
Provisions. By completing this lesson, you should have the knowledge to
discuss the following topics. Take a moment to see if you can do the following:
•
•
•
Describe why safety program is important and state competent and
qualified person
Summarize elements of a safety and health program
Explain OSHA's basic safety standards
SUBPART D: Health Hazards
Introduction
The construction process traditionally has been perceived as a labor-intensive job that
offers some of the most challenging working conditions in industry. Conditions can be
hot, cold, dusty, dark, or noisy. Construction workers can also be exposed to a wide
variety of chemicals.
OSHA defines a health hazard as the following: [sign posts this text. This will be a
banner template with more of these banners within the lesson]
The term health hazard "means a chemical for which there is statistically significant
evidence based on at least one study conducted in accordance with established
scientific principles that acute or chronic health effects may occur in exposed
employees. The term 'health hazard' includes chemicals which are carcinogens, toxic
or highly toxic agents, reproductive toxins, irritants, corrosives, sensitizers,
hepatotoxins, nephrotoxins, neurotoxins, agents which act on the hematopoietic
system, and agents which damage the lungs, skin, eyes, or mucous membranes...."
Is this still the case on some construction job sites?
Do we have health hazards around us on the construction site every day?
Lesson Overview
Welcome to the "Health Hazards and Controls" lesson of the Turner OSHA
Certification course. This lesson will help the learner understand the types of health
hazards affecting construction work and learn how to manage the associated health
risks. The lesson also will cover the hazard communication standard and the role of
industrial hygiene.
Upon
•
•
•
•
completing this lesson, you will be able to:
Identify general provisions for occupational health and safety
Recognize safe illumination intensities and ventilation systems at the worksite
Appraise and prevent extreme exposures to extreme heat, cold, and noise
Manage operations that have potential for overexposure to radiation, gases,
and lead
• Prepare a hazard communication program including compiling Material Safety
Data Sheets
• Identify the role of industrial hygiene in preventing health hazards
Why Learn This Lesson?
It is not uncommon in construction to encounter potential environmental hazards
from materials/processes used during construction or while uncovering
hidden/unknown hazards. OSHA in fact cites numerous violations each year. Note As
reflected in the chart below, lead and gas exposures in the workplace remain
dangerous.
Accordingly, it is essential that environmental conditions be identified and satisfactory
risk management strategies be put in place.
Topic 1: Overview
This topic introduces the management of general health hazard provisions. Upon
completing this topic, you will be able to:
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•
•
•
Identify the responsibilities that employers have for providing medical services
and first aid in the workplace
Classify the levels of training for the Certified First Aid Provider, CPR, and EMS
Identify the need to protect yourself from infectious diseases when rendering
first aid
Determine the workplace requirements for drinking water, facilities, showers,
and vermin control
Medical Services and First Aid
Arrangements for medical services and first aid are to be made prior to the start of a
project. Plus, the employer must ensure the availability of medical personnel for
advice and consultation on matters of occupational health.
Personnel
Medical services must be reasonably accessible through a trained first
aid person and/or the local emergency responder (in non-911 areas the
telephone numbers must be posted).
In the absence of an infirmary, clinic, hospital, or physician reasonably
accessible in terms of time and distance to the worksite, a person trained in
first aid must be available at the worksite to render first aid. This person must
have a valid certificate in first aid training from the U.S. Bureau of Mines, the
American Red Cross, or equivalent training that can be verified by documentary
evidence.
Supplies
First aid supplies must be easily accessible. By assessing the specific needs of
their workplace, employers can ensure that the supplies for which one could
reasonably anticipate a need are available. Employers should assess the
specific needs of their worksite periodically and augment the first aid kit
appropriately.
It is important to note that the contents of the first aid kit must be sealed in a
weatherproof container and appropriate PPE, including gloves, should be
provided for exposure to blood; consultation with the local Fire/Rescue
Department, appropriate medical professional, or local emergency room may
be helpful to employers in determining what the first aid kit should contain.
Transportation
Proper equipment for prompt transportation of the injured person to a
physician or hospital, or a communication system for contacting necessary
ambulance service, must be provided.
911
In areas where 911 is not available, the telephone numbers of the physicians,
hospitals, or ambulances must be conspicuously posted.
Facilities
Where the eyes or body of any person may be exposed to injurious corrosive
materials, suitable facilities for quick drenching or flushing of the eyes and
body must be provided within the work area for immediate emergency use.
Good Samaritan Laws
Most states have enacted Good Samaritan laws to encourage people to help
others in emergency situations. These laws give legal protection to people who
provide emergency care to ill or injured persons. They require that the Good
Samaritan use common sense and a reasonable level of skill not to exceed the
scope of the individual's training in emergency situations.
Levels of Training
OSHA states, "In the absence of an infirmary, clinic or hospital in the near proximity
of the workplace which is used for the treatment of all injured employees, a person or
persons must be adequately trained to render first aid. First aid supplies approved by
the consulting physician must be readily available."
In the workplace it is often the job of a Certified First Aid Provider to assist in
stabilizing an injured or ill person until professional medical help arrives. Certified
First Aid Providers are persons who are certified and trained to certain levels in first
aid and cardiopulmonary resuscitation (CPR).
CPR
Basic first aid and CPR courses are approximately eight hours long and are
certified through a number of nationally recognized organizations such as The
American Red Cross, The American Heart Association, and The National Safety
Council, to name a few. These certifications also should be updated biannually.
First Responder is a trade name for a 40-hour certification course in
advanced first aid and CPR. Hospitals, technical colleges, and fire
departments teach this course; certification must be updated biannually.
Informed, trained citizens are indispensable in helping people in emergencies.
To help citizens be more prepared for emergency situations, the American Red
Cross trains people in first aid and CPR.
EMS
Due to the increased need for first aid services, an Emergency Medical Services
force (EMS) has been established in most communities. However, it remains
equally important that citizens be trained in first aid and know what to do until
the EMS or another emergency medical professional arrives.
When should I call for medical assistance?
It depends on your company policies and procedures. If the victim is unconscious, call
911 or your local emergency number. If the victim is conscious, call an ambulance
unless they ask that an ambulance not be called; call 911 or an ambulance anyway IF
the victim:
• Is or becomes unconscious
• Has trouble breathing or is breathing in a strange way
• Has chest pain or pressure
•
•
•
•
•
•
•
Is bleeding severely
Has pressure or pain in the abdomen that does not go away
Is vomiting or passing blood
Has seizures, a severe headache, or slurred speech
Appears to have been poisoned
Has injuries to the head, back, or neck
Has possible broken bones
Infectious Diseases
Infectious diseases are diseases that pass from one person to another. These are
referred to most commonly as bloodborne or airborne pathogens.
In first aid, bloodborne and airborne pathogens are most often transmitted through
touching, breathing, and biting. People can become infected if touched by an infected
person, or if the germs in that person's blood or other bodily fluids pass into the body
through breaks in the skin or through the lining of the mouth, nose, or eyes.
Therefore, the greatest risk is in touching another person's blood or bodily fluids
directly, without protective gloves or some other protective barrier.
Below are some basic guidelines to follow that will help reduce body fluid transmission
when rendering first aid care:
• Avoid direct contact with bodily fluids and blood whenever possible.
• Place barriers, such as gloves or a clean, dry cloth, between the victim's bodily
fluids and yourself.
• Wear protective clothing, such as disposable gloves, to cover any cuts, scrapes
or skin conditions you have.
• Wash your hands with soap and water immediately after giving care.
• Do not eat, drink or touch your mouth, nose or eyes when giving first aid.
• Do not touch objects that may be soiled with blood or other bodily fluids.
• Be prepared by having a first aid kit stocked and easily accessible.
By following these simple guidelines, you can reduce the risk of getting or
transmitting infectious diseases.
Basic Provisions
Drinking Water
Potable water means water that meets the quality standards prescribed in the U.S.
Public Health Service Drinking Water Standards, published in 42 CFR part 72, or
water that is approved for drinking purposes by the State or local authority having
jurisdiction.
Portable containers that are used to dispense drinking water on the job site have to
be tightly closed, equipped with a tap, and set up not to tip. The container used to
distribute drinking water has to be clearly marked as to the nature of its contents and
not used for any other purpose.
Where single-service cups (disposable) are supplied, there has to be both a sanitary
container for the unused cups and a receptacle for disposing of the used cups.
Toilet Facilities
Toilets shall be provided for employees according to the OSHA requirements table.
Note: These requirements do not apply to mobile crews that have transportation
readily available which will allow them to get to nearby toilet facilities.
Washing Facilities
On every construction site there should be adequate washing facilities for employees
who work with paints, coatings, herbicides, or insecticides, or in other operations
where they are exposed to harmful contaminants. The washing facilities should be
near the job site, be properly equipped to allow employees to remove these types of
substances, and maintained in a sanitary condition.
Showers
Whenever showers are required by a particular standard, they must meet the
following criteria:
• One shower must be provided for every 10 employees of each sex, or
numerical fraction thereof, who are required to shower during the same shift.
• Body soap or other appropriate cleansing agents convenient to the showers
must be provided.
• Showers must be provided with hot and cold water feeding a common
discharge line.
• Employees who use showers must be provided with individual clean towels.
Change Rooms
Whenever employees are required by a particular standard to wear protective clothing
because of the possibility of contamination with toxic materials, change rooms
equipped with storage facilities for street clothes and separate storage facilities for
the protective clothing must be provided.
Vermin Control
Every enclosed workplace should be constructed to prevent the entrance or harborage
of rodents, insects, and other vermin. A continuing and effective extermination
program must be instituted where their presence is detected.
Process Safety Management
The contract employer working on-site must be informed of the hazards by the host
employer and must train each of the employees in the safe work practices for that
project.
The safety and health procedures of the host employer as well as those of the
contractor must be followed.
Waste Operations
Written safety and health programs for hazardous waste operations are required.
Training, medical surveillance, engineering controls, work practices, and personal
protective equipment are included in the standard.
Spray Booths
OSHA has specific regulations covering spray booths, electrical and other sources of
ignition, ventilation, fixed electrostatic apparatus, electrostatic hand-spraying
equipment, and drying, curing or fusion apparatus.
Topic Summary
Please take a moment to review these major points before you continue with the next
topic.
• As the construction workplace continues to evolve, the industry must revisit its
basic medical services.
• Prior to the start of a project, employers must provide (1) a trained first aid
person, (2) first aid supplies easily accessible when required, (3) facilities for
flushing corrosive materials, and (4) a system to provide emergency
transportation.
• Adhere to the basic guidelines for reducing the risk of contracting infectious
diseases when rendering first aid care.
• In emergency situations, a Good Samaritan uses common sense and
reasonable levels of skill not to exceed the scope of their training.
• There are guidelines for basic sanitation including drinking water, toilet and
washing facilities, showers, and vermin control.
Topic 2: Lighting and Ventilation
This topic discusses the health hazards associated with lighting and ventilation
encountered at the worksite. Upon completing this topic, you will be able to:
•
•
•
•
•
Identify the three categories of electrical lighting
Describe the different types of lamps
Determine the recommended illumination intensities for area and office lighting
Recognize how a light's CRI (color-rendering index) affects how people and
objects look
Explain the precautions for using local exhaust and abrasive blasting ventilation
systems
Illumination
Lighting or illumination is necessary in every workplace to ensure a safe and
productive environment. In situations where natural lighting is not sufficient,
electrical lighting must be supplied.
Electrical lighting can be divided into three categories:
• General lighting produces uniform light levels throughout the entire facility.
• Supplemental lighting provides more intense light levels that general lighting
cannot provide for small areas or workstations.
• Emergency lighting is used when electrical power is disrupted. It can take the
form of battery- or generator-powered systems.
Types of Lamps
Incandescent
Incandescent lamps are the most familiar type of light source and can be used for
general, supplemental, or decorative lighting. They are available in a variety of styles
including standard, tubular, decorative, three-way, and rough-service bulbs; and
reflective spot and flood lamps.
Incandescent bulbs are readily available in stores, are easy to install, and their life
span is not affected by switching them on and off.
Halogen
Halogen lamps generate light by using a thin filament wire enclosed in a quartz tube
that contains a pressurized gas such as halogen, iodine, or bromine. This design
allows the bulb to burn hotter, which produces a whiter, brighter light more efficiently
than an incandescent bulb. Halogen bulbs are used for accent lighting, display
lighting, outdoor floodlamps, and automobile headlights. The bulbs come in compact
sizes, do not blacken with use, and provide an intense and focused light.
Fluorescent
Fluorescent lamps create light by passing an electric arc through an inert gas.
Fluorescent lamps provide high levels of general lighting very efficiently. They can last
10 to 20 times longer than an incandescent light and use one-fifth to one-third the
electricity to generate the same brightness. A drawback to fluorescent lights is that
they can be dimmed only with expensive special equipment and are sensitive to cold
temperatures.
Compact Fluorescent
Compact fluorescent lamps operate in a similar fashion as linear fluorescent lamps.
These lamps are designed for use in standard incandescent sockets and serve as
energy-saving replacements to incandescent lights. To maximize the life of the bulb,
compact fluorescent must be used in locations where they stay on for several hours
at a time. No lamp dimming is possible.
High-Intensity Discharge
High-intensity discharge (HID) lamps generate light by passing electrical current
through an internal tube filled with a blend of gases under pressure. Three types of
HID lighting available include mercury, high-pressure sodium, and metal halide - all in
a screw-base bulb. These lamps are the most energy-efficient bright lights that
provide long life in hot or cold environments. HIDs take a few minutes to warm up as
they gradually reach full brightness.
Light Level Recommendations
The amount of light required for any space depends greatly on what activity is taking
place in the space. Providing too little light reduces productivity and accuracy while
too much may cause discomfort or eye fatigue. The following light level
recommendations are for area, office, and industrial lighting.
Construction areas, ramps, runways, corridors, offices, shops, and storage areas
must be lighted to not less than the minimum illumination intensities listed in this
table while any work is in progress:
General Construction Lighting Levels
Area of Operation
General construction areas, concrete placement, excavation and
waste areas, access ways, active storage areas, loading platforms,
refueling, and field maintenance areas
General construction area lighting
Indoors: warehouses, corridors, hallways, and exitways
Tunnels, shafts, and general underground work areas (Exception:
A minimum of 10 foot-candles is required at tunnel and shaft
heading during drilling, mucking, and scaling. Bureau of Minesapproved cap lights must be acceptable for use in the tunnel
heading.)
General construction plant and shops (e.g., batch plants,
screening plants, mechanical and electrical equipment rooms,
carpenter shops, rigging lofts and active storerooms, mess halls,
and indoor toilets and workrooms)
First aid stations, infirmaries, and offices
Foot-Candles
3
5
5
5
10
30
Note: A foot candle is a unit of illumination, beginning at a point on the surface which
is one foot from, and perpendicular to, a uniform point source of one candle.
What is the conversion between lumen, candlepower, foot-candle, and lux?
Given that 1 lumen/sq ft = 1 foot-candle, 1 lux = 1 lumen/sq meter, and 1 sq ft =
0.0929 sq meter, then 1 lux = 0.0929 foot-candle and 1 foot-candle = 10.76 lux.
EX: 1 lux/0.0929 = 10.76 lux
Color of Light
The color of light created by a light bulb affects how people and objects look. The
higher the color-rendering index (CRI), the better that bulb will make objects appear.
A color rendering of 70 or more is best.
Another consideration is the amount of "warmth" or "coolness" of the bulb. A warm
bulb gives off a yellow-white light, while a cool bulb gives off a white light on a
neutral surface. Incandescent and warm fluorescent bulbs generally strengthen red,
orange, yellow hues while weakening blue hues. Cool fluorescent bulbs generally
strengthen orange, yellow, and blue hues and weaken red hues.
What is color temperature?
Color temperature is defined as the balance of wavelengths making up any "white"
light. The higher the color temperature, the cooler or more blue the light source. The
unit of measurement is in degrees kelvin (K). For example, a typical color
temperature for an incandescent light is 2800K and 4100K for a cool white
fluorescent.
Ventilation
Clean air is something most of us take for granted. However, air quality on a
construction site is affected by many things, such as welding operations, chemicals
used in various processes, and the use of heaters. But do we really know what the
substance or chemical is? How do we protect ourselves?
Whenever hazardous substances such as dusts, fumes, mists, vapors, or gases exist
or are produced in the course of construction work, their concentrations must not
exceed the limits specified by OSHA. These limits are found in OSHA Standard
1926.55, Appendix A.
When ventilation is used as an engineering control method, the system has to be
installed and operated according to the requirements set by OSHA.
Local Exhaust Ventilation
When local exhaust ventilation is used, it must be designed to prevent dispersion into
the air of dusts, fumes, mists, vapors, and gases in concentrations causing harmful
exposure. It must also ensure that dusts, fumes, mists, vapors, or gases are not
drawn through the work area of employees.
Design and operation
Exhaust fans, jets, ducts, hoods, separators, and all necessary appurtenances
(including refuse receptacles) must be designed, constructed, maintained, and
operated to ensure the required protection. They must maintain a volume and
velocity of exhaust air sufficient to gather dusts, fumes, vapors, or gases from said
equipment or process and convey them to suitable points of safe disposal, thereby
preventing their dispersion in harmful quantities into the atmosphere where
employees work.
Duration of operations
The exhaust system must be in operation continually during all operations it is
designed to serve.
Since dust capable of causing disability is, according to the best medical opinion, of
microscopic size and tends to remain for hours in suspension in still air, it is essential
that the exhaust system continue operating for a time after the work process or
equipment served by that system has ceased, to ensure the removal of the harmful
elements to the required extent.
For the same reason, employees wearing respiratory equipment should not remove
their equipment until the atmosphere seems clear.
Disposal of exhaust materials
The air outlet from every dust separator and the dusts, fumes, mists, vapors, or
gases collected by an exhaust or ventilating system must discharge to the outside
atmosphere.
Collecting systems, which return air to the work area, may be used if concentrations
that accumulate in the work area air do not result in harmful exposure to employees.
Dust and refuse discharged from an exhaust system must be disposed of in a way
that will not result in harmful exposure to employees.
Abrasive Blasting
Abrasive blasting is the forcible application of an abrasive to a surface by pneumatic
pressure, hydraulic pressure, or centrifugal force.
Dust hazards from abrasive blasting
Abrasives and the surface coatings on the materials blasted are shattered and
pulverized during blasting operations, and the dust formed will contain particles of
respirable size. The composition and toxicity of the dust from this source shall be
considered in making an evaluation of the potential health hazards. Below are
considerations for using abrasive blasting techniques.
• The concentration of respirable dust or fume in the breathing zone of the
abrasive-blasting operator or any other worker must be kept below the levels
specified by OSHA.
• Organic abrasives, which are combustible, must be used only in automatic
systems.
• The blast nozzle must be bonded and grounded to prevent the buildup of static
charges.
Topic Summary
Please take a moment to review these key points before you continue with the next
topic.
• General, supplemental, and emergency lighting ensure a safe and productive
work environment.
• There are five types of lamps: incandescent, halogen, fluorescent, compact
fluorescent, and high-intensity discharge.
• OSHA provides a reference table of minimum illuminations intensities for area
and office lighting.
• A color rendering of 70 or more is best for lighting.
• Whenever hazardous substances such as dusts, fumes, mists, vapors, or gases
exist or are produced by construction work, their concentrations must not
exceed the limits specified by OSHA.
• Local exhaust and abrasive blasting ventilation systems are designed and
operated to prevent harmful exposure to employees.
Topic 3: Heat, Cold, and Noise
This topic presents the basic methods for preventing illnesses on the job from
exposure to extreme heat, cold, and noise. Upon completing this topic, you will be
able to:
• Identify and prevent heat-related illnesses
• Define hypothermia and explain the correlation between core body
temperature, symptoms, and treatment
• Explain the Occupational Noise Exposure Standard and its relation to noise
recognition, evaluation, and control
Heat Hazards
During the summer months or in hot operations, employers should be especially
aware of the dangers associated with working in high-temperature environments.
Heat and humidity combined with physical exertion can do more than just make
employees uncomfortable - it can lead to a variety of heat-related illnesses that can
debilitate employees.
Basic methods for preventing heat-related illnesses on the job include the following:
•
•
•
•
•
•
•
Wear loose-fitting clothing
Drink water often (don't wait until you're thirsty)
Schedule "hot" jobs for the cooler part of the day (early morning or late
afternoon)
Schedule routine maintenance and repair work in hot areas during the cooler
seasons of the year
Provide additional breaks and comfortable break areas
Add additional personnel to reduce exposure time for each member of a crew
Permit workers the freedom to interrupt work when they feel extreme heat
discomfort
An awareness of the symptoms of heat-related illnesses and the control measures to
prevent them will help keep your employees safe and your workplace up and running.
Heat-Related Illnesses
Cramps
Heat cramps are painful muscle spasms. They can occur after vigorous exercise or
intense physical activity in extreme temperatures. Abdominal, calf and thigh muscles,
and the biceps/triceps are most frequently affected. If cramping occurs, the person
should rest and cool down, drinking water with one teaspoon of salt per quart.
Affected individuals also may feel faint and should be taken to a cool place and
manual pressure applied to the cramped muscle.
Rash
Heat rash, or prickly heat, appears as fine red spots or small bumps. It's usually
found where clothing is somewhat restrictive (i.e., on the neck and upper back, chest,
or arms). This harmless rash is triggered by hot, humid weather when one is dressed
too warmly and develops when skin is persistently wetted by perspiration. However,
the small, inflamed spots on the skin can become infected. The condition usually
disappears when the skin is cooled and dried.
Exhaustion
Heat exhaustion is a result of excessive heat and dehydration. It generally is caused
by insufficient water and salt intake and too little sweat, which evaporates on the skin
to cool the body. Symptoms of heat exhaustion can have a sudden onset and include
pale, clammy skin, fatigue, dizziness, nausea, vomiting, labored breathing, rapid
pulse, and intense thirst. Syncope (fainting) is a milder form of heat exhaustion and
is brought on by having to stand for long periods of time in a hot environment; it is
caused by the pooling of blood in the heat-dilated vessels of the legs.
A victim of heat exhaustion should be cooled as rapidly as possible by placing the
individual flat or with feet slightly elevated in front of a fan or in a cool room.
Administer cool liquids (not icy) and seek medical attention. More severely exhausted
patients may need I.V. fluids, especially if vomiting prevents them from keeping
liquids down.
Heat Stroke
Heat stroke is caused by overexposure to extreme heat and a breakdown of the
body's heat-regulating mechanisms. In the initial and most crucial stage of heat
stroke, a victim will exhibit an altered mental state such as disorientation or
confusion. This altered consciousness is the key to diagnosing heat stroke. All heat
stroke victims will exhibit an altered mental state; this is not true for those suffering
from heat exhaustion or extreme sunburn.
Victims of heat stroke often have hot, dry, flushed skin; a rapid heartbeat; and
abnormally high body temperature (105.8 F). Until medical assistance is available,
the victim should receive any or all of the following treatments:
• Cooled rapidly by placing him or her in a shady area
• Submersed in a cool bath
• Wrapped in wet sheets
• Exposed to increased air movement to improve evaporative cooling
• Sprayed with lukewarm water and fanned with a towel
Once a victim's rectal temperature is reduced to 102.2°F, cooling methods should be
stopped.
Even though it is important to replace fluids as soon as possible, liquids should NOT
be administered to a victim in an altered mental state of heat stroke - there is a risk
of these liquids being aspirated into the lungs. Medical professionals will give I.V.
fluids to an individual suffering from heat stroke when they arrive at the scene.
Cold Hazards
People who work outside or enjoy outdoor recreational activities face the risks of
hypothermia and frostbite.
Hypothermia is a risk that is often overlooked or not recognized. Because
hypothermia can affect reasoning and judgment, you can quickly find yourself in a
life-or-death situation without realizing that you are in danger.
Hypothermia is defined as "a decrease in core body temperature to a level at which
normal muscular and cerebral functions are impaired."
The most common cause of this loss of body temperature is exposure to cold and/or
wet conditions. When exposed to cold conditions, the body can lose heat through a
variety of routes:
•
•
•
Conduction (contact with cold or wet objects, such as snow or wet clothing)
Convection (heat being carried away from the body by wind, i.e., wind chill)
Evaporation (sweating and respiration)
Once the body's core temperature begins to drop below 98.6 F, the symptoms of
hypothermia will start to appear. The symptoms of hypothermia are varied and
depend on the body's core temperature. A person suffering from a mild case may
exhibit shivering and a lack of coordination, while a person suffering from severe
hypothermia may be incoherent, exhibit muscular rigidity, and can potentially
succumb to cardiac arrest. Once it is determined that someone is suffering from
hypothermia, it is critical to begin treatment immediately.
Q.
Can hypothermia be a problem even if the temperature is well above freezing?
Yes. Hypothermia can occur any time the body cannot generate enough heat to
maintain its core temperature, regardless of the time of year. Even on a sunny
summer day, a person immersed in water 40° to 50°F may reach the exhaustion
point (due to a lowered core temperature) in as little as 30 minutes, and death from
hypothermia may result in only 3 hours.
Q.
Can the medications I'm taking make me more susceptible to hypothermia?
A. Yes. A number of commonly prescribed medications can affect the body's
resistance to hypothermia. Sedatives, antidepressants, tranquilizers, and
cardiovascular drugs all can affect the body's ability to regulate temperature. If you
are concerned about the effect your medications may have on your body's resistance
to hypothermia, please contact your doctor or pharmacist for more information.
Is frostbite a threat?
Frostbite is also a very real concern in cold weather conditions. The extremities fingers, hands, toes, feet, nose, and ears - are particularly susceptible to frostbite.
Symptoms of frostbite are a paling, numbing, and hardening of the skin.
To treat frostbite, seek medical attention as soon as possible and:
•
Remove any wet clothing or clothing that may restrict blood flow to the
effected area.
•
•
Soak the frostbitten appendage in warm water, approximately 105°F. After 2540 minutes, the area should be warmed until the normal color, feeling, and
movement have returned.
Dry the area and wrap it in a dry cloth.
Hypothermia Treatment
Severity of
Body
Hypothermia
Temperature
(°F)
Mild
98.6-97
97-95
Moderate
95-93
93-90
Symptoms
Shivering begins
Cold sensation,
skin numbness,
goose bumps, lack
of hand
coordination
Intense shivering,
general lack of
muscular
coordination, slow
or stumbling pace,
mild confusion,
pale skin
Violent shivering,
gross lack of
muscular
coordination,
mental
sluggishness,
amnesia, difficulty
speaking
Treatment
Remove all wet clothing and
replace it with warm, dry
clothes. Encourage the victim
to stay active and to drink a
warm (not hot), sugary
liquid. Avoid offering liquids
containing alcohol and/or
caffeine, as alcohol can
increase heat loss and
caffeine tends to cause
dehydration.
Again, replace all wet clothing
with warm, dry clothes. Be
sure to cover the victim's
head, as this is a major
source of heat loss. If the
victim is able to swallow
without danger, give warm,
sugary liquids to drink. Place
warm objects, such as hot
water bottles, next to the
victim's head, neck, chest,
and groin to help increase
core body temperature;
body-to-body contact is also
an effective means of
warming the victim. Finally,
take the victim to a medical
facility as soon as possible.
Severe
90-86
86-82
82-78
Shivering stops,
muscular stiffness,
extreme confusion
or incoherence,
irrational behavior,
inability to stand,
skin appears blue
and/or puffy
Muscular rigidity,
semiconsciousness,
decreased pulse
and respiration,
dilation of pupils,
skin ice-cold to
touch
Unconsciousness,
pulmonary edema,
erratic pulse and
heartbeat, cardiac
and respiratory
failure, death
A person suffering from
severe hypothermia may
easily be mistaken for dead.
Even if the victim is cold,
rigid, and has no detectable
pulse, continue treatment. It
is vital that a person suffering
from severe hypothermia get
to a medical facility as quickly
as possible, even before
treatment is attempted. While
waiting for professional
assistance, replace the
victim's wet clothing with
warm, dry clothes. Always
handle the victim gently;
when the heart reaches
temperatures below 90°F, it
is very susceptible to cardiac
arrest. If the victim does
suffer a cardiac arrest,
administer CPR until
professional help arrives.
Cold Stress Prevention
Individuals exposed to wet clothing, high winds, low temperature or any combination
thereof are potentially susceptible to cold stress. An individual's best defense against
cold stress is wearing the proper clothing, following cautious work guidelines, and/or
using engineering controls.
Preventing Hypothermia
Clothing
•
•
•
•
Waterproof clothing is necessary for wet or rainy conditions.
Tight-knit clothing provides wind resistance
Insulated hats, gloves, and footwear keep the extremities protected.
Layering clothing allows the individual to adjust to changing temperatures.
Work Practices
•
•
•
•
•
•
Perform work practices during the warmest part of the day.
Take frequent short breaks in a warm, dry place.
Drink beverages that are warm and sweet (such as sport drinks) and avoid
beverages that contain caffeine or alcohol.
Eat warm, high-calorie foods to fuel the body and help prevent fatigue.
Use the buddy system when spending time outdoors, if possible.
Be familiar with the signs of hypothermia.
Engineering Controls
•
•
•
•
An on-site heat source, such as air jets, radiant heaters or contact warm plates
A shielded work area for drafty or windy conditions
A heated shelter for employees exposed to wind-chill temperature of 20°F or
less
The use of thermal insulating material on equipment handles when
temperatures drop below 30°F
Knowing the facts about cold exposure and following safe work practices can ensure
that the cold weather work season is a safe one.
Noise Hazards
Occupational noise exposure may be one of the most significant health hazards
present in the modern industrial workplace. Not only does it affect the employees who
have suffered or will suffer permanent hearing loss as a result of exposure to unsafe
levels of industrial noise, it also costs employers who must financially compensate
these workers.
Occupational Noise Exposure Standard
As OSHA standards go, the Occupational Noise Exposure Standard is a relatively userfriendly document. It's extremely thorough, thus eliminating much of the reader
interpretation that most standards require.
The standard essentially implements a three-pronged approach to addressing
industrial noise. The basic components are:
• Recognition
• Evaluation
• Control
Training and record-keeping are used to support each of the standard's basic
components. The standard's importance cannot be underestimated.
Noise Recognition
Safe Noise Levels
Before it can be determined whether an employee is being exposed to an unsafe level
of noise, an "unsafe" level must be defined. OSHA identifies 90 decibels (dB) based
on an eight-hour time-weighted average (TWA) as the absolute "safe" level of noise
exposure. This 90dB concentration is referred to as the OSHA Permissible Exposure
Limit (PEL) for noise exposure. Any eight-hour TWA exceeding 90dB requires the
employer to implement control measures to reduce the exposure to 90dB or below.
Control Measures
In addition to the 90dB PEL, OSHA also recognizes an 85dB TWA as its action level.
While employee exposure to the action level does not force the employer to
implement measures to reduce employee noise exposure, it is good management
practice to establish a hearing conservation program at this level.
Hearing Conservation Program
Employers must conduct noise exposure monitoring, perform audiometric testing on
employees, provide hearing protection to employees who request it, conduct
employee training, and retain records of the aforementioned activities.
Monitoring Noise Levels
OSHA states that noise levels must be monitored "when information indicates that
any employee's exposure may equal or exceed an eight-hour time-weighted average
of 85 decibels."
As a general rule of thumb, if an individual's voice must be raised to converse at a
distance of three feet, the noise level probably exceeds 85dB. At the very least, this is
an indication that monitoring should be conducted.
Two basic types of instruments are available to monitor noise levels: sound level
meters and noise dosimeters. Both instruments measure in decibels.
It's important to note that decibels are not linear units like feet or pounds. The
decibel is a dimensionless unit that expresses a logarithmic ratio to an established
reference level. To put the decibel into perspective, remember that while a reading of
10 decibels is 10 times greater than one decibel, a reading of 20 decibels is 100 times
greater (10 x 10) than one, and a reading of 30 decibels is 1000 times greater (10 x
10 x 10). This logarithmic ratio is similar to the Richter scale used to measure
earthquakes.
Institute audiometric testing and training
Should the noise level monitoring determine that employees are being subjected to
levels equaling or exceeding the 85dB action level, the next step is to establish an
audiometric testing program for those exposed. In addition, the employer must
provide hearing protectors (earmuffs or ear plugs) at no cost and institute a training
program for all affected employees. According to OSHA, the training program must be
conducted annually and ensure that employees are informed of the:
•
•
•
Effects of noise on hearing
Purpose of hearing protectors
Advantages, disadvantages, and attenuation of various types of hearing
protectors
•
•
•
Instructions on the selection, fitting, use, and care of protectors
Purpose of audiometric testing
Test procedures
Evaluating Noise
The backbone of the employee evaluation is the audiometric test. This is more
commonly referred to as a hearing test. OSHA details the requirements of an
audiometric testing program.
What types of hearing tests are there?
An audiometric program that documents an employee's hearing level consists of two
types of tests, or audiograms: baseline and annual. The baseline audiogram must be
conducted within six months of confirmation of an exposure equal to or exceeding the
85dB action level. It establishes a reference point to which future annual audiograms
can be compared. The initial annual audiogram must be conducted within one year of
the baseline. Subsequent annual audiograms must be performed yearly thereafter.
How are the test results evaluated?
By comparing the annual audiogram to the baseline audiogram, an employer can
evaluate whether an employee has experienced any recordable hearing loss during
this period. This hearing loss is referred to in the OSHA standard as a standard
threshold shift (STS).
OSHA defines an STS as "a change in hearing threshold relative to the baseline
audiogram of an average of 10dB or more at 2000, 3000, and 4000 Hz in either ear."
Should the audiogram results indicate an STS has occurred, OSHA requires that the
affected employee be fitted (or refitted) with hearing protectors, trained on their
proper use, and required to wear them. The employee must be informed of the STS
and may be referred for further audiometric testing.
Who administers the testing?
When it comes to audiometric testing, OSHA is quite specific about who can
administer the test and the type of equipment that must be used. OSHA references
the criteria for those who can perform audiometric tests. Basically, OSHA requires a
licensed or certified audiologist or a technician who is certified by the Council of
Accreditation in Occupational Hearing Conservation and gives detailed specifications
for the instrumentation required.
The employer is required to retain all of the audiometric test records for a given
employee for the duration of the affected employee's employment.
Controlling Noise
Protection against the effects of noise exposure must be provided when the sound
levels exceed those shown in the chart below, when measured on the A scale of a
standard sound level meter at slow response.
TABLE - PERMISSIBLE NOISE EXPOSURES
__________________________________________________
|
| Sound level
Duration per day, hours
| dBA slow
| Response
___________________________________|______________
|
8..................................|
90
6..................................|
92
4..................................|
95
3..................................|
97
2..................................|
100
1 1/2..............................|
102
1..................................|
105
1/2................................|
110
1/4 or less........................|
115
___________________________________|______________
When employees are subjected to sound levels exceeding those listed in the table
above, feasible administrative or engineering controls must be instituted. If such
controls fail to reduce sound levels within the levels of the table, personal protective
equipment as required by OSHA must be provided and used to reduce sound levels
within the levels of the table.
NOTE: Although not required by OSHA, it is good management practice to
implement a hearing conservation program at the 85db action level.
When it comes to hearing protection, OSHA requires that employees be given the
opportunity to select their hearing protectors from a variety of suitable options, and
that the employer provide training on the use and care of the selected devices.
Personal protective equipment (PPE) is available in two basic formats: earmuffs,
which fit over the entire external ear and seal against the side of the head, and ear
plugs, which are inserted directly into the ear canal.
Topic Summary
OSHA states that heat, cold, and noise levels must be monitored and controlled.
Please take a moment to review these key points before you continue with the next
topic.
•
•
•
•
Heat and humidity combined with physical exertion can lead to these heatrelated illnesses: cramps, rash, exhaustion, and heat stroke. Be aware of the
basic methods for preventing such illnesses.
Hypothermia is defined as a decrease in core body temperature to a level at
which normal muscular and cerebral functions are impaired. There is specific
treatment for the varying symptoms for mild, moderate, and severe cases.
The safe level of noise is 90 decibels (dB) based on an eight-hour timeweighted average (TWA).
There are permissible noise exposures that, if exceeded, are subject to
administrative, engineering, or PPE controls. As a general rule of thumb, if an
individual's voice must be raised to converse at a distance of three feet, the
noise action level has been exceeded ( 85dB).
Topic 4: Radiation, Gases, and Lead
This topic briefly covers the safety management of radiation, gases, and lead. Future
lessons in this program will cover these exposures in more detail. Upon completing
this topic, you will be able to:
• Identify protection against occupational exposure to radiation
• Describe the administrative and engineering controls to avoid exposure to
airborne contaminants
• Assess and implement controls to keep lead exposure at low levels
Radiation
Employers must protect against occupational exposure of ionizing and non-ionizing
radiation.
Training Levels
•
Only competent and trained persons can use equipment that involves
radioactive materials or X-rays.
•
Laser equipment operators must have proof of qualification. Signs, safety
equipment, and safe practices must be used with lasers.
•
In construction and related activities involving the use of sources of ionizing
radiation, the pertinent provisions of the Nuclear Regulatory Commission
Standards for Protection Against Radiation (10 CFR Part 20), relating to
protection against occupational radiation exposure, must apply.
•
Any activity that involves the use of radioactive materials or X-rays, whether or
not under license from the Nuclear Regulatory Commission, must be performed
by competent persons specially trained in the proper and safe operation of such
equipment.
•
In the case of materials used under Commission license, only persons actually
licensed, or competent persons under direction and supervision of the licensee,
may perform such work.
•
Only qualified and trained employees must be assigned to install, adjust, and
operate laser equipment.
•
Proof of qualification of the laser equipment operator must be available and in
the operator's possession at all times.
Operating Equipment
•
Areas in which lasers are used must be posted with standard laser warning
placards.
•
Beam shutters or caps must be used, or the laser turned off, when laser
transmission is not actually required.
•
When the laser is left unattended for a substantial period of time, such as
during lunch hour, overnight, or at change of shifts, the laser must be turned
off.
•
Only mechanical or electronic means may be used as a detector for guiding the
internal alignment of the laser.
•
The laser beam must not be directed at employees.
•
When it is raining or snowing, or when there is dust or fog in the air, the
operation of laser systems must be prohibited where practicable; in any event,
employees must be kept out of range of the area of source and target during
such weather conditions.
•
Laser equipment must bear a label to indicate maximum output.
Employee Protection
•
Employees must not be exposed to light intensities above these levels:
o
o
o
Direct staring: 1 microwatt per square centimeter
Incidental observing: 1 milliwatt per square centimeter
Diffused reflected light: 2 1/2 watts per square centimeter
•
Employees, when working in areas with a potential exposure to direct or
reflected laser light greater than 0.005 watts (5 milliwatts), must be provided
with anti-laser eye protection devices as specified by OSHA.
•
A laser unit in operation should be set above the heads of the employees, when
possible.
•
Employees must not be exposed to microwave power densities in excess of 10
milliwatts per square centimeter.
Gases, Vapors, and Fumes
Administrative or engineering controls must be used if feasible to avoid employee
inhalation, ingestion, or skin exposure to airborne contaminants. When such controls
are not feasible to achieve full compliance, protective equipment or other protective
measures must be used to keep employees' exposure to air contaminants within the
limits prescribed in this section. OSHA specifies controls for the operations and
contaminants listed in this table.
•
•
•
•
•
•
•
•
•
•
Operations
Air Contaminants
Abrasive blasting
Grinding
Polishing
Buffing
Spray finishing operations
Open surface tanks
Formaldehyde
Airborne asbestos
•
•
•
Tremolite
Amthophyllite
Actinolite dust
Ventilation systems must be effective and safe. Whenever respirators are used, their
use must comply with OSHA standards.
Employees' exposure to inhalation, ingestion, skin absorption, or contact with any
material or substance at a concentration above those specified in the "Threshold Limit
Values of Airborne Contaminants for 1970" of the American Conference of
Governmental Industrial Hygienists must be avoided.
Employees' exposure to airborne asbestos, tremolite, anthophyllite, formaldehyde, or
actinolite dust is covered by OSHA in other standards.
Lead
In October 1992, President Bush signed Section 1031 of Title X of the Housing and
Community Development Act of 1992, requiring OSHA to develop an interim standard
for lead in the construction industry. This interim standard had to provide guidelines
for protection of construction workers from occupational exposure to lead that was as
effective as the HUD (Department of Housing and Urban Development) guidelines and
OSHA's lead standard for general industry.
On May 4, 1993, the final interim rule for lead in the construction industry was
issued. This can be found in Subpart D of Title 29 Code of Federal Regulations (CFR)
1926.62.
The standard provided for compliance, training, and signs. Basically, employers must
conduct an initial exposure assessment and implement engineering and work practice
controls to keep lead exposure at or below the Permissible Exposure Limit (PEL).
These methods should be supplemented, if necessary to achieve compliance, with
respiratory and other clothing protection. Programs must be written and hygienic
facilities and practices must be maintained. Monitoring, medical surveillance, and
record-keeping are required. In addition, OSHA guidelines require comprehensive
training for everyone who may be potentially exposed to lead. Furthermore, signs
must be posted to warn employees of the danger of lead in the area and should state
the following: "Warning," "Lead Work Area," "Poison," and "No Smoking or Eating."
Such signs also must be illuminated and cleaned as necessary to ensure legibility.
Think a minute of questions you have about lead exposure. Now click the questions
below for answers.
Where can lead be found?
Many people associate lead with paint, but it is also present in many other places.
Lead may be present in your drinking water, which is polluted by the lead in pipes, or
in soil from the combustion of leaded gasoline, which was phased out in the late '80s
and early '90s. Although lead in these forms can be dangerous, most exposures to
lead poisoning occur during lead paint removal.
How does lead enter the body?
Lead can enter the body by means of ingestion or inhalation. Once it has entered the
body, it is then absorbed by the blood stream, which circulates it throughout the
entire body. While the lead is being circulated, the body attempts to filter it out.
Some of the lead is filtered out, but much of it is absorbed by soft tissue such as the
kidneys, liver, and brain tissue or hard tissue such as bones and cartilage.
How does lead exposure affect our health?
Health effects from lead can vary depending on the length and level of exposure.
Some common symptoms include: loss of appetite, dizziness, and a metallic taste in
the mouth, In an acute exposure, an individual is exposed to a high level of
contaminant over a short period of time. Exposures like this can result in a condition
called encephalopathy, which affects the brain and quickly develops into seizures,
coma, and death from cardiorespiratory arrest.
How is lead exposure tested?
•
Determination of air concentrations. Two pieces of equipment are needed for
this: a personal air sampling pump and a membrane filter. These can be
attached to an employee for personal monitoring or used for area monitoring.
Note: The exposure level to lead in construction and general industry is 50
µg/m3 (microgram per meter cubed) for air concentration.
•
Determination of water/soil concentrations. Obtain a water/soil test kit or
submit a sample to a laboratory.
•
Determination of blood lead level. A physician can determine this by testing a
blood sample.
Note: Once the lead level has been determined, it should be compared with the
recommended level.
•
Remediation of Lead. Lead can be handled in the following ways:
•
•
•
•
•
Replacement-remove the entire piece and replace
Encapsulation-cover the lead with another material
Chemical removal-remove lead by chemical process
Physical removal-remove lead by heat gun and manual scraping
Blasting-remove by water or vacuum
Note: Before removing lead, consult with state OSHA and EPA regulations.
Lead must be disposed of according to state or local ordinances.
What are safe work practices?
When working with lead, you should follow certain practices:
•
•
•
•
•
•
•
Provide exhaust ventilation.
Use only HEPA (High-Efficiency Particulate Absolute) vacuums for cleanup.
Use a NIOSH/MSHA-approved respirator. (The type will be determined by the
exposure level.)
Do NOT eat, drink, or smoke in lead- contaminated areas.
Use proper protective clothing, shoe covers, and gloves.
Wash hands thoroughly before eating.
Shower and change into clean clothes before leaving the worksite.
Methylenedianiline
Methylenedianiline (pronounced meth' uh-leen-die-an'ah-leen) is an industrial
chemical that is not known to occur naturally. It is also commonly known as MDA. It
occurs as a colorless-to-pale yellow solid and has a faint odor. OSHA has set an
occupational exposure limit of 0.081 milligrams of MDA per cubic meter of air for an
8-hour workday, 40-hour workweek. Overexposure may cause skin irritation and liver
damage.
Employers must follow these precautionary guidelines:
•
•
•
•
•
Compile written plans for emergency situations
Provide training
Monitor exposure
Establish and mark regulated areas where exposures can occur
Provide personal protective equipment
•
•
•
Provide decontamination areas and keep work areas as clear of MDA as
possible
Share information with other contractors
Provide a medical surveillance program including initial and subsequent
periodic examinations
Topic Summary
Please take a moment to review these key points before you continue with the next
topic.
• Only competent and trained employees can operate and maintain radioactive,
X-ray, and laser equipment.
• Follow OSHA's training levels and operating and employee protection
requirements when working with radioactive equipment.
• Airborne contaminants must be controlled within OSHA standards by ventilation
systems, PPE, and industrial hygienist supervision.
• Monitoring, medical surveillance, remediation, and record-keeping are required
to control workplace exposure to high levels of lead.
Topic 5: Health Hazard Communication
This topic covers OSHA's Hazard Communication Standard in detail and points out the
role of the industrial hygienist. Upon completing the topic, you will be able to:
• Define the Hazard Communication Standard and describe its six major
categories
• Understand the purpose of the Material Safety Data Sheet Guidelines and
identify its 16 sections
• Define industrial hygienist and explain how the industrial hygienist controls and
prevents health hazards
OSHA's Standards
A written hazard communication program is required that includes training, labeling,
and the availability and use of Material Safety Data Sheets.
The Hazard Communication Standard, also known as the Right-to-Know law, was first
enacted on November 25, 1983, by OSHA. It was later modified with minor changes
and technical amendments to take effect March 11, 1994.
The purpose of the standard is to ensure that chemical hazards in the workplace are
identified and evaluated, and that information concerning these hazards is
communicated to employers and employees.
This transfer of information is to be accomplished by means of a comprehensive
hazard communication program, which includes container labeling and other forms of
warning, Material Safety Data Sheets (MSDS), and employee training.
In addition to the hazard communication program, employers are required to
implement training programs prior to the start of the job to instruct each employee in
the recognition and avoidance of unsafe conditions and the regulations applicable to
the work environment. This Word document specifies the health-related training
requirements.
Standard Categories
The standard has six major categories.
• Hazard Determination
• Material Safety Data Sheets
• Chemical Labeling
• Employee Training
• The Written Program
• Trade Secrets
Hazard Determination
Hazard determination requires employers to identify and evaluate all chemicals used
in the workplace. This evaluation is based on two hazard categories: listed and
defined.
Listed hazards are those included in one of the following references:
•
•
•
•
OSHA 29 CFR 1910.1000 Z tables
American Conference of Governmental Industrial Hygienists (ACGIH) Threshold
Limit Values (TLV)
The National Toxicology Program
The International Agency for Research on Cancer
Defined hazards are those specified by OSHA as physical or health hazards, such as:
•
•
•
•
•
Combustible liquids
Oxidizers
Corrosives
Reproductive toxins
Nontoxins
Chemicals exempted from the standard include:
•
•
•
•
•
•
•
•
•
•
•
Wood and wood products (except wood dust)
Regulated hazardous waste
Tobacco products
Food
Drugs
Cosmetics
Alcoholic beverages
Agricultural or vegetable seed treated with pesticides
Various types of pesticides
Nuisance particulate
Articles
These are exempt because they are all regulated by separate government standards.
Material Safety Data Sheets (MSDS)
Material Safety Data Sheets require documentation of chemical hazards. Once you
have evaluated and identified all the hazardous chemicals in your workplace, you
must document them and obtain an MSDS for each item. MSDS are available from the
chemical supplier or manufacturer. These sheets contain specific chemical hazard
information such as:
•
•
•
•
•
•
•
•
•
Physical hazards
Health hazards
Routes of entry
Exposure limits (if any)
Precautions for safe handling and use (if known)
Spill cleanup procedures
Personal protective equipment to be used
Emergency and first aid procedures
Name, address, and telephone number of the chemical manufacturer
All the information on the MSDS must be in English and be available to employees
working with or near the hazardous chemical.
Chemical Labeling
Chemical labeling requires labels on all chemicals in the workplace. The label should
contain these items:
•
•
•
Identity of the material
Appropriate hazard warnings
Name and address of the manufacturer, importer, or other responsible party
Other appropriate warning information (such as pictures and symbols) may be used in
conjunction with the hazard information. Labels must be legible and in English. Labels
in a second language may be added as long as the English label is present.
Employee Training
Employee training requires employers to provide employees with effective information
and training on hazardous chemicals in their work area at the time of their initial
assignment and whenever a new physical or health hazard is introduced into the area.
The training must include:
•
•
•
•
Methods and observations used to detect the presence or release of the
chemical
Physical and health hazards
Protective measures
Labeling and explanation of the MSDS
The Written Program
The written program requires employers to fully document the actions taken to
comply with all provisions of the standard and to list the responsible person(s) for
each area of the program. A copy of the written program must be made available,
upon request, to all employees and OSHA officials.
Trade Secrets
Hazard communication involves manufacturer trade secrets. The chemical
manufacturer may withhold the chemical identity, including the chemical name and
other specific information, from the MSDS. However, under special conditions health
care professionals may obtain this secret information.
Topic Summary
•
A written hazard communication program is required that includes training,
labeling, and the availability and use of Material Safety Data Sheets.
•
The communication standard is comprised of six major categories:
o
o
o
o
o
o
Hazard Determination
Material Safety Data Sheets
Chemical Labeling
Employee Training
The Written Program
Trade Secrets
•
The MSDS has 16 sections that provide consistent hazardous reporting
information.
•
Industrial hygienists are trained to anticipate, recognize, evaluate, and
recommend controls for workplace conditions that may cause workers injury or
illness.
Lesson Summary
This lesson contains information and instruction about health hazards. By completing
this lesson, you should have the knowledge to discuss the topics described below.
Take a moment to see if you can do the following:
• Identify general provisions for occupational health and safety
• Recognize safe illumination intensities and ventilation systems at the worksite
• Appraise and prevent extreme exposures to extreme heat, cold, and noise
• Manage operations that have potential for overexposure to radiation, gases,
and lead
• Prepare a hazard communication program including compiling Material Safety
Data Sheets
• Identify the role of industrial hygiene and its role in preventing health hazards
Personal Protective Equipment
Introduction
Bureau of Labor Statistics data reflect an alarming number of injuries each
working day. On average, there are:
•
•
•
•
200 eye injuries
475 head injuries
650 foot injuries
1150 hand injuries
Personal protective equipment (PPE) for the head, ears, hands, eyes, foot,
body, and respiration are designed to prevent or lessen the severity of injuries
in your workplace. In your construction site, you often are exposed to flying
material chips, falling objects, heat, light, and other hazards requiring special
PPE.
OSHA created the original standards for the use of personal protective
equipment in 1971. The standards had become outdated, however, and were
not meeting the goal of protecting employees.
In order to provide important clarifications and protect workers from injury
and illness, OSHA revised the standards in 1994.
Lesson Overview
This lesson addresses the types of hazards requiring PPE, the types of PPE,
reasons for wearing PPE, types of protection devices, and their care and use.
Upon completing this lesson, you will be able to:
• Identify the types of hazards requiring PPE including impact,
penetration, compression, chemical/harmful dust, temperature,
light/radiation, noise, and electrical
• List the types of PPE
• Describe why you must wear PPE
• Distinguish typical hazards and types of protection devices for each type
of PPE
• Explain how to properly care for and use:
o
o
o
o
o
o
o
Head protection
Hearing protection
Hand protection
Eye protection
Foot protection
Protective clothing
Respiratory protection
Why Learn This Lesson?
Using personal protective equipment requires hazard awareness and training
on the part of the user. You must be aware that the equipment does not
eliminate the hazard but instead provides protection, while exposure is still a
risk. Selecting the proper personal protective equipment for a job is very
important, and both employers and employees must understand the
equipment's purpose and its limitations.
This lesson addresses the types of equipment most commonly used to protect
the head (including eyes and face) and the torso, arms, hands, and feet. The
use of respiratory protective equipment to protect against life-threatening
hazards also is covered. This lesson is dedicated to the safety and health of
the employees by focusing on the protective qualities of personal protective
equipment and on its proper use and maintenance.
Topic 1: The Types of Hazards Requiring PPE
You first need to identify the type of hazards before you can select the
appropriate PPE. Every job on the construction site has unique characteristics
and, therefore, different hazards.
Two main categories of hazards are physical hazards and health hazards. The
types of hazards that fall under these categories are impact, penetration,
compression, chemical/harmful dust, temperature, light/radiation, noise, and
electrical.
Upon completing this topic, you will be able to
• Identify the categories and types of hazards.
•
State the most common citations issued by OSHA for violations of the
PPE standards.
Two Categories of Hazards
The two distinct categories of hazards are:
Physical Hazards
A physical hazard can lead to bodily harm as a result of contact with the
hazardous agent, such as being struck by tools or equipment, falling from an
elevation, being splashed by chemical agents, or being burned. The following
injuries can result from contact with a physical hazard:
•
•
•
•
•
Cuts and bruises
Broken bones
Head and eye injuries
Burns
Smashed fingers and hands
Health Hazards
A health hazard causes sickness or disease as a result of exposure to the
hazardous agent, such as exposure to silica, asbestos, or lead. Health hazards
include:
•
•
•
Biohazards -- blood-borne diseases from contact with blood and bodily
fluids
Gases -- exposure to poisonous carbon monoxide from mechanical
equipment and vehicles
Fumes -- from welding certain metals
Types of Hazards
The OSHA standards for PPE require that the employer perform a hazard
assessment to identify the sources of hazards.
A hazard can be a physical or health hazard or both.
Impact Hazards
An impact can occur during work operations from various tools, equipment,
materials, or the work environment itself. Tools, debris, or building materials
can fall or be dropped from elevated work surfaces. Stacked and suspended
materials also have the potential to fall when they are loaded or stored
improperly.
During operations involving chipping or hammering, objects and debris can be
propelled across work areas. This can pose a hazard to other workers in the
area or those passing through the job site. In addition, low-clearance
structures and machinery being used on the job site pose an impact hazard to
employees.
Penetration Hazards
Some impact hazards must be evaluated to determine if they are potential
penetration hazards. A falling object with a sharp edge or point could cause a
penetrating injury. There also are many penetration hazards on the
construction site that workers can come into contact with either by stepping
on them or striking up against them.
Compression Hazards
Machinery or processes where there is movement of equipment or building
products has the potential for compressing anything that is caught in its path
or in pinch points that are created by the movement.
Hazards From Chemicals/Harmful Dusts
Many operations involve the use of hazardous chemicals that may be released
into the air or absorbed through the skin. The use of solvents, adhesives, and
gases are common sources of chemical contaminants. In addition, fumes from
welding operations or other cutting or burning operations can release toxic
substances into the air. Dusts from operations such as grinding can be just as
harmful as any chemical.
Not all air contaminants are as easily recognized on the job site. In fact,
sometimes it is the absence of certain gases rather than their presence that
can pose the health hazard. Suffocation can occur in confined spaces or
trenches from a lack of oxygen in the air.
Temperature Hazards
Excessive temperatures due to weather or work operations pose a serious
hazard to workers. A cold winter day or excessive summer heat can dictate
the need for PPE. In addition, handling hot or cold materials, performing hot
work such as welding, or the potential for fire must be considered when
identifying the need for PPE.
Light/Radiation Hazards
Welding, cutting, and brazing are common sources of radiation. PPE must be
selected based on the type of exposure. With the increased use of lasers in the
industry, other sources must be considered when assessing workplace
hazards.
Noise Hazards
Exposing the ear to high levels of noise may cause temporary or permanent
hearing loss. Temporary hearing loss occurs after only a few minutes of
exposure to an intense noise but is recoverable following a period of time
away from the noise. If the noise exposure is repeated, there may be only a
partial hearing recovery and the loss can then become permanent.
Electrical Hazards
Because electricity is such a common energy source, the danger of electrical
hazards is often overlooked. In any hazard assessment, the power used to
operate all equipment should be checked. Particular attention must be paid to
temporary power and extension cords. Faulty wiring is frequently the cause of
electrical shock and a leading source of fires in the construction industry.
Topic Summary
Please take a moment to review these points before you continue with the
next topic.
• The two distinct categories of hazards are:
o Physical hazards: Bodily harm results from contact with the
hazardous agent
o Health hazards: Sickness or disease results from exposure to the
hazardous agent
• OSHA organizes workplace hazards into the following types:
o Impact hazards: Various tools, equipment, materials, or the work
environment itself; stacked or suspended materials
o Penetration hazards: Falling objects with a sharp edge or point
•
o Compression hazards: Machinery or processes that have the
potential for compressing anything
o Hazards from chemical/harmful dust: The use of solvents,
adhesives, or gases; the creation of fumes and dusts
o Temperature hazards: Excessive temperatures, handling hot or
cold materials, performing hot work such as welding, or the
potential for fire
o Light/radiation hazards: Welding, cutting, or brazing
o Noise hazards: Exposing the ear to high levels of noise
o Electrical hazards: Temporary power, extension cords, and faulty
wiring
The largest number of violations occurred in head protection. The next
largest number of violations occurred in eye and face protection, PPE
provided, used, and maintained, safety nets for falls over 25 feet, and
life jackets/vests.
Topic 2: The Types of PPE
In this topic you will read about the types of PPE you must wear based on the
hazard assessment your employer has provided. You also will learn the
reasons for wearing PPE. Upon completing this topic, you should be able to:
•
•
List the types of PPE
Describe why you must wear PPE
Why You Must Wear PPE
There are various types of PPE you must wear in your construction site.
Head Protection
The brain controls all of our daily activities. If damage occurs to the brain, the
impact on one's life and the lives of loved ones can be devastating. The lasting
effects of head traumas can render a person helpless to perform some of the
daily activities that we all take for granted such as driving a car, walking, or
even playing with our children.
Prevention of head injuries is an important factor in every safety program. A
survey by the Bureau of Labor Statistics (BLS) of incidents and injuries notes
that most workers who suffered impact injuries to the head were not wearing
head protection. The majority of workers were injured while performing their
normal jobs at their regular worksites.
Hearing Protection
Let's think about the importance of your hearing for a moment. Imagine that
you must strain to hear your favorite TV program or listen to your favorite CD,
or play them so loudly they make everyone else leave the room. Just imagine
that you have trouble hearing everyday conversations with family members or
co-workers from less than 20 feet away.
Imagine that you have beautiful grandchildren. Now imagine that you must
wear a hearing aid to hear their laughter, or worse yet, you can't hear them at
all.
Unfortunately, these situations are all too real for many workers in the
construction industry. Many suffer significant hearing loss after 15 to 20 years
of working unprotected in an environment where they are subjected to
excessive noise from machinery, daily operations on the site, tools, and even
traffic.
In addition to posing safety problems on the job, the loss of one's hearing can
have a dramatic impact on the quality of one's life.
Fortunately, hearing loss in the construction industry is completely preventable
through a combination of better and quieter equipment, hearing conservation
programs, and use of proper hearing protection.
Hand Protection
Take a moment to hold your hands out in front of you. Look at them. They are
the only two hands you will ever have. It has been estimated that almost 20
percent of all disabling incidents on the job involve the hands. Without your
fingers or hands, your ability to work would be greatly reduced. Human hands
are unique. No other creature in the world has hands that can grasp, hold,
move, and manipulate objects like human hands. Hands are one of your
greatest assets. And, as such, they must be protected and cared for.
Eye Protection
A BLS study found that about 60 percent of workers who suffered eye injuries
were not wearing eye protection equipment. When asked why they were not
wearing face protection at the time of the incident, workers indicated that face
protection was not normally used or practiced in their type of work, or it was
not required for the type of work performed at the time of the incident.
However, you must wear eye protection all the time to protect your eyes.
Foot Protection
Scientists and engineers for centuries have marveled at the design and
structure of the human foot. The human foot is rigid enough to support the
weight of your entire body and yet flexible enough to allow you to run, dance,
play sports, and go anywhere you want. Without your feet and toes, your
ability to work at your job would be greatly reduced. As such, the foot must be
protected and cared for.
Protective Clothing
Wearing the right clothes to work takes on meaning beyond self-pride. It
demonstrates your awareness of safety and the impact your dress has on the
job. The hazards faced on any particular day may change, but the fact that
your safety depends on dressing appropriately for the job is constant.
Beginning with your shirt, evaluate the tasks you will perform that day. If you
will be working around machinery or equipment with moving parts, don't wear
long sleeves. They may become tangled in the pinch points. Don't wear any
loose-fitting clothes around machinery with moving parts. The same is true of
your pants. It is most certain that cutoffs or other shorts are not appropriate
at any time on a construction site but especially if you will be welding or
performing other hot operations.
Another factor to be aware of is the weather. Wool will help keep you warmer
in cold weather. Cotton will breathe and absorb perspiration in hot weather,
while protecting you from the sun's radiation.
Any action you take to avoid or reduce injury will be to your benefit. Dress
appropriately for the job.
Respiratory Protection
Construction employees are exposed to a variety of respiratory hazards.
Welding fumes and vapors from solvents being used, and the dusts that are
generated by many of the construction site operations fill the air with
potentially harmful contaminants. If these are not controlled by proper
ventilation they can pose a serious hazard to workers on the site.
But when you are worried about breathing toxic chemicals on the job, you can
always put on a dust mask, right?
Wrong! Dust masks are good for keeping out most large particles of dust, but
that's about all they do. They don't stop chemical fumes, vapors, or even very
small dust particles.
Respirators are a lot more effective. They may not be the best way to prevent
chemical exposure, but for many construction jobs they are the only practical
way. Just wearing any old mask isn't enough. You have to use the right
respirator for the job, it has to fit properly, and you have to be trained how to
use it. Otherwise, you only have the illusion of protection.
Topic Summary
Please take a moment to review these points before you continue with the
next topic.
•
The types of PPE covered in this topic include:
o Head protection equipment (hardhats)
o Hearing protection equipment (earplugs, ear caps, earmuffs)
o Hand protection equipment (gloves)
o Eye protection equipment (safety glasses, safety goggles, face
shields, welding helmets)
o Foot protection equipment (safety shoes and boots)
o Protective clothing equipment (special vests, aprons, jackets)
o Respiratory protection equipment (respirators)
Topic 3: Head Protection
Prevention of head injuries is an important factor in every safety program. A
survey by the Bureau of Labor Statistics (BLS) of incidents and injuries notes
that most workers who suffered impact injuries to the head were not wearing
head protection. The majority of workers were injured while performing their
normal jobs at their regular worksites.
In this topic, you will learn about head protection in detail. Upon completing
this topic, you should be able to:
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•
•
Summarize typical hazards requiring head protection equipment
Explain types of head protection devices
Use and care for head protection equipment
Typical Hazards Requiring Head Protection Equipment
Many situations on the construction site offer the potential for incidents that
could result in an injury to the head.
The most common hazard is falling objects. Tools, materials, or debris can fall
from elevated positions and present a hazard to employees working below.
Falling objects are not the only hazard. Flying objects from site operations
such as grinding, hammering, or chipping also pose a hazard. In addition, the
hazard of electrical shock also is present at many construction site locations.
OSHA requires that head protection be worn at any time an employee is
working in an area where there is a possible hazard from impact/penetration,
from falling or flying objects, or from electrical shock.
Head Protection Devices
A hardhat is the device to be worn to protect your head. Hardhats protect you
by providing the following features:
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•
•
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A rigid shell resists and deflects blows to the head.
A suspension system inside the hat acts as a shock absorber.
Some hats serve as an insulator against electrical shocks.
It shields your scalp, face, neck, and shoulders against splashes, spills,
and drips.
•
Some hardhats can be modified so you can add face shields, goggles,
hoods, or hearing protection.
OSHA has cited the standards specified by the American National Standards
Institute (ANSI) for hardhats as meeting these requirements.
Every hardhat conforming to the requirements of ANSI Z89.1must be
appropriately marked to verify its compliance. The following information must
be marked inside the hat:
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•
The manufacturer's name
The legend, "ANSI Z89.1"
The class designation (A, B, or C)
Requirements of ANSI Z89.1
Before discussing the components of the ANSI standard, it's important first to
make a distinction between protective helmets (more commonly known as
hardhats) and bump caps.
NOTE. Bump caps do not comply with the ANSI guidelines and are not
acceptable for occupations or applications where OSHA requires an ANSIcompliant hardhat.
The ANSI standard separates hardhats into two types and three classes. Of
the two types:
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•
Type 1 helmets incorporate a full brim (the brim fully encircles the dome
of the hat).
Type 2 helmets have no encircling brim but may include a short bill on
the front (similar to a baseball cap).
In terms of electrical protection, ANSI recognizes three classes.
•
Class A helmets are intended to reduce the force of impact of falling
objects and to reduce the danger of contact with exposed low-voltage
electrical conductors. For certification, sample shells are proof-tested at
2200 volts of electrical charge.
•
•
Class B helmets are intended to reduce the force of impact of falling
objects and to reduce the danger of contact with exposed high-voltage
electrical conductors. Sample shells are proof-tested at 20,000 volts.
Class C helmets are intended to reduce the force of impact of falling
objects, but offer no electrical protection.
In most instances, workers on a construction site will wear a Class A hard hat.
The use of Class B hard hats is usually limited to electrical workers who are
exposed to greater electrical hazards. Due to the lack of electrical shock
protection, Class C hard hats are not in widespread use on construction sites.
In addition to electrical protection, hard hats are also tested for impact and
penetration resistance from blows to the top of the head, flammability
resistance, and water absorption. The rigorous testing requirements are
described in detail within the standard. (Link to the standard)
In 1997 ANSI published a revision to its Z89.1 protective headwear standard.
While the revision, ANSI Z89.1(1997), has not yet been adopted into 29 CFR
1910.135, it does contain some notable changes. The revision eliminates the
old Type 1 and Type 2 (full brim vs. no encircling brim) design designations. In
the new standard, "Type" is used to designate whether a helmet provides
protection strictly from blows to the top of the head (Type I) or protection
from blows to both the top and sides of the head (Type II).
In addition, the new standard also changed the alpha designations for the
classes of electrical performance. Under Z89.1(1997), the following three
classes are recognized:
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•
Class G (General) helmets: This is equivalent to the old Class A. Class G
helmets are proof-tested at 2200 volts.
Class E (Electrical) helmets: This is equivalent to the old Class B. Class E
helmets are proof-tested at 20,000 volts.
Class C (Conductive) helmets: This class provides no electrical
insulation; the alpha designation did not change from the old standard.
Hardhats also must contain user information under the 1997 standard. In
addition to the manufacturer's name, ANSI legend, and class designation,
helmets compliant with Z89.1(1997) must be marked with the date of
manufacture. Instructions pertaining to sizing, care, and service life guidelines
also must accompany the hardhat.
Care and Use of Hardhats
To ensure that your hardhat will function properly in the event of an incident
at the worksite, you should adhere to the following guidelines.
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•
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NEVER paint the hardhat or apply stickers to it. This can hide defects in
the hardhat. Some paints also may weaken the compound used to
construct the hardhat or may limit its resistance to electrical hazards.
NEVER use a hardhat that appears damaged. This could limit the level of
protection the hardhat provides. Notify a supervisor immediately.
NEVER store or carry hardhats in the rear window of an automobile.
Sunlight and severe heat can adversely affect the degree of protection
provided by certain hardhat components.
NEVER drill holes in the hardhat. Holes can weaken the impact and
penetration protection properties of the hardhat.
Do hardhats have a predetermined service life?
One common misconception is that hardhats have a predetermined service
life. This is not true. Both the 1986 and 1997 ANSI standards address service
life under maintenance and care of the hardhat. Those standards state that all
hardhat components should be inspected daily for signs of dents, cracks,
penetration, and any damage due to impact, rough treatment, or wear. Any
hardhat that fails the visual inspection should be removed from service until
the problem is corrected.
In addition to everyday wear and tear, ultraviolet (UV) radiation can pose a
problem for hats constructed of plastic materials. Damage caused by UV
radiation is easy to spot: the hat will lose its glossy finish and eventually take
on a chalky appearance. Further degradation could cause the shell to actually
start flaking away. Once the effects of UV radiation are detected, the hardhat
shell should be replaced immediately.
Checklist for Hardhats
Please remember the following checklist before and when you wear a hardhat.
•
•
•
•
•
•
ANSI Z89.1 should be stamped inside the hardhat.
The suspension should be free from defects such as broken connectors.
The suspension should be adjusted properly to provide clearance.
The shell should still have a glossy finish.
The hardhat should be free from paint, stickers, or other marks that
could hide defects.
The shell should be free from cracks or indentations.
Topic Summary
Please take a moment to review these points before you continue with the
next topic.
• The device to be worn to protect your head is a hardhat. The material,
shape, and condition of the outer shell and the suspension system inside
the hardhat are all designed to protect the head from impact,
penetration, and electrical shock.
• Hardhats should have the following information inside them:
• The manufacturer's name
• The legend, "ANSI Z89.1"
• The class designation (A, B, or C)
• To ensure that your hardhat will function properly in the event of an
incident at the worksite, you should adhere to the following guidelines:
o NEVER paint the hardhat or apply stickers to it.
o NEVER use a hardhat that appears damaged.
o NEVER store or carry hardhats in the rear window of an
automobile.
o NEVER drill holes in the hardhat.
Topic 4: Hearing Protection
In this topic you will learn about hearing protection. Work-related hearing loss
continues to be a critical workplace safety and health issue. The National
Institute for Occupational Safety and Health (NIOSH) and the occupational
safety and health community named hearing loss one of the 21 priority areas
for research in the next century. Noise-induced hearing loss is 100 percent
preventable but once acquired, hearing loss is permanent and irreversible.
Therefore, prevention measures must be taken by employers and workers to
ensure the protection of workers' hearing. OSHA requires a hearing
conservation program to protect workers from hazardous exposures to noise.
Upon completing this topic, you should be able to:
•
•
•
Summarize typical hazards requiring hearing protection equipment
Describe types of hearing protection devices
Use and care for hearing protection equipment
Typical Hazards Requiring Hearing Protection Equipment
Damage can occur instantaneously from extremely loud noises or gradually
from exposure to elevated noise levels over an extended period of time.
Vibration creates sound waves. Any operation on the construction site that
causes equipment, tools, or other materials to vibrate results in sound. The
greater the energy source, the greater the volume of sound. If the noise
exceeds 90dB during the work shift, OSHA requires hearing protection to
prevent permanent damage to the ears.
Many of the tools and equipment used on the job site create loud sounds.
Loud noise can cause:
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Hearing loss, temporary or permanent
Tinnitus, a constant or periodic ringing or roaring in the ears
Inability to hear signals and safety warnings
Stress, poor concentration, headaches, etc., from straining to hear
Hearing Protection Devices
The purpose of hearing protection devices is to reduce the noise level to an
acceptable level. The following types of hearing protection devices are used
most commonly on construction sites:
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•
•
Earplugs
Ear caps
Earmuffs
Each hearing protection device should have a noise reduction rating (NRR)
that will be expressed in decibels (dB). Earplugs and earmuffs should have an
NRR that will reduce noise levels in the work area to below 90 dB. There are
no standards for ear caps.
Earplugs
Earplugs are made of soft, pliable material that is designed to protect your ear
from noise hazards by fitting into and sealing the ear canal. Some earplugs are
disposable, to be used one time and then thrown away. The nondisposable
type should be cleaned after each use for proper protection. Plain cotton is
ineffective as protection against hazardous noise. There are many different
types of earplugs:
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•
•
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Triple flange
Single flange
Silicone
Foam
Triple- and single-flange earplugs are preformed and resemble an umbrella.
These types of plugs come in several sizes and should be properly fitted to
provide the proper level of protection. Be sure to test both ears, as you may
need a different size for each ear.
Foam and silicone earplugs can be shaped by hand. Silicone earplugs are
tapered and inserted into the canal with the remaining materials being pressed
into the outer ear. For foam earplugs, the user tapers one end of the earplug
by rolling it between their fingers and then inserts it into the ear canal. The
earplug then expands to fill the space and provide protection.
Ear Caps
Ear caps are small, soft pods, pads, or flexible tips that seal the ear at or near
the entrance to the ear canal with only a minimal amount of insertion. They do
not enter into the ear canal and should be worn only for occasional noise
exposures. A band connecting the caps is worn either over the head, around
the neck, or under the chin to hold the ear caps in place.
Earmuffs
Earmuffs are noise-attenuating cups with soft cushions and a connecting band
that are worn around the outer ear to seal out noise. The band is adjustable so
that one size will fit most workers.
Earmuffs are most popular in applications where there is a need to remove
and replace the hearing protection device frequently.
Earmuffs must make a perfect seal around the ear to be effective. Glasses,
long sideburns, long hair, and facial movements such as chewing can reduce
protection. Special equipment is available for use with glasses or beards.
There are some disadvantages to earmuffs. They can be bulky and interfere
with certain operations. In hot environments they can be uncomfortable, and
sets with metal head frames cannot be used near high voltage.
For extremely noisy situations, earplugs should be worn in addition to
earmuffs. When used together, earplugs and earmuffs change the nature of
sounds; all sounds are reduced, including one's own voice, but other voices or
warning signals are easier to hear.
Care and Use of Hearing Protection Devices
As with every piece of PPE, hearing protection devices require care and
maintenance.
You should:
• Inspect hearing protection before each use. Report and don't use
earmuffs or ear caps that are loose, cracked, or don't seal well, or
earplugs that are cracked or inflexible.
• Wash hands thoroughly before inserting or putting on hearing
protection.
• Clean hearing protection devices regularly with warm, soapy water and
following the manufacturer's recommendations. Do not use alcohol,
acetone, or other chemicals because they dry out the components,
which compromises their protective qualities.
• Store hearing protection devices where they will stay clean and dry.
Checklist for Earmuffs and Earplugs
Please remember the following checklist before you use earmuffs and
earplugs.
Earmuffs
The headband should provide the proper tension.
The earmuffs should be free from cracks or tears, allowing a proper seal
around the ears.
The cushions of the earmuffs should be soft, clean, and ensure a proper
seal around the ears.
The earmuffs should have an NRR that will reduce noise levels in the
work area below 90 dB.
Earplugs
Preformed plugs should be fitted properly and used only by the
individual for whom they were made.
Foam and silicone plugs should be pliable, allowing the user to form the
plug and properly insert the plug into the ear.
Disposable foam and silicone earplugs should be kept readily available
and in the original package until ready for use.
Reusable, preformed and form earplugs should be kept cleaned and
disinfected.
Reusable plugs should not be hardened or discolored.
Earplugs should have an NRR that will reduce noise exposure below 90
dB.
Employees should know how to insert earplugs properly.
Ear Caps
The headband should provide the proper tension.
The ear caps should be free from cracks or tears, allowing a proper seal.
The ear caps should not be hardened or discolored.
There are no standards NRR for ear caps.
Employees should know how to insert ear caps properly.
Topic Summary
Please take a moment to review these points before you continue with the
next topic:
• If the noise exceeds 90dB during the work shift, hearing protection is
required to prevent permanent damage to the ears.
• The following types of hearing protection devices are used most
commonly on construction sites:
•
•
•
•
o Earplugs: Earplugs are made of soft, pliable material that is
designed to protect your ear from noise hazards by fitting into and
sealing the ear canal.
o Ear Caps: Ear caps are small, soft pods, pads, or flexible tips that
seal the ear at or near the entrance to the ear canal with only a
minimal amount of insertion.
o Earmuffs: Earmuffs are noise-attenuating cups with soft cushions
and a connecting band that are worn around the outer ear to seal
out noise. Earmuffs are most popular in applications where there is
a need to remove and replace the hearing protection device
frequently.
Inspect hearing protection before each use.
Wash hands thoroughly before inserting or putting on hearing
protection.
Clean hearing protection devices regularly using warm, soapy water and
following manufacturers recommendations. Do not use alcohol, acetone,
or other chemicals.
Store hearing protection devices where they will stay clean and dry.
Topic 5: Hand Protection
You learned about hearing protection in the previous topic. In this topic you
will learn hand protection. On every construction site, fingers and hands are
exposed to cuts, scratches, bruises, and burns. Although it is difficult to
protect your fingers completely, because you need them for practically every
construction operation, you can shield them from common injuries with the
proper protective equipment.
Upon
•
•
•
completing this topic, you should be able to:
Summarize typical hazards requiring hand protection equipment
Explain the types of hand protection devices
Use and care for hand protection equipment
Typical Hazards Requiring Hand Protection Equipment
The hands have potential exposure to more hazards on the jobsite than any
other part of the body. Because they are used in nearly every task performed
in construction, they are constantly at risk of an injury.
Examples of injuries to arms and hands are burns, cuts, electrical shock,
amputation, and absorption of chemicals.
Some of the work that is performed on the construction site requiring the use
of hand protection includes:
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Welding operations
Handling chemicals
Electrical work
Working with concrete
Handling metals
Hand Protection Devices
There is a wide assortment of gloves, hand pads, and sleeves for protection
from various hazardous situations. These devices should be selected to fit the
job. For example, some gloves are designed to protect against specific
chemical hazards. You may need to use gloves that have been tested and
provide insulation from burns and cuts, such as those made of wire mesh,
leather, and canvas.
There are many types of gloves for many types of hazards. The following are
the most common types found in the construction industry.
Heat-resistant gloves: Protect against burns and discomfort when the hands
are exposed to sustained conductive heat
Metal mesh gloves: Used by those who work constantly with knives,
protecting against cuts and blows from sharp or rough objects
Rubber gloves: Worn by electricians
Neoprene and vinyl gloves: Used when handling chemicals and corrosives.
Neoprene and vinyl are particularly useful when handling petroleum products
Leather gloves: Generally used for most heavy duty work, due to their ability
to resist sparks, moderate heat, chips, and rough objects
Cotton fabric gloves: Suitable for protection against dirt, slivers, chafing, or
abrasions. Not heavy enough for multi-purpose use in handling rough, sharp,
or heavy materials
Care and Use of Hand Protection Devices
If a glove is damaged or inappropriate for the job, it can do more harm than if
you were wearing no glove at all. For instance, a glove that is immersed in an
incompatible solution could dissolve onto your hand.
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Wear Get the type of glove with the hazard involved Many gloves are suited to a particular hazard. If the glove you have is
not proper for the work being done, select another glove)
Check for holes, scratches, and cracksIf welding leathers have holes, your hands will be unprotected if molten
metal hits those areas.
Check the color of the glove - Discoloration is a sign of a breakdown in
the glove's composition. It is time to replace the glove.
Check the elasticity of the glove When a glove is hardened, it means it is defective. This will result in
cracks and exposure to hazards.
Check the thickness of the glove If the glove shows signs of thinning, it is time for a replacement.
Make sure the glove fits properly.
Checklist for Gloves
Please remember the following checklist before and when you wear gloves.
Gloves should provide the protection necessary for the hazard being
encountered.
The gloves should be free from holes and tears.
The gloves should be free from scratches and cracks.
There should be no discoloration of the gloves.
The gloves should still be thick enough to provide protection.
The gloves should fit properly.
The employee should be able to perform his or her job while wearing the
gloves.
Topic Summary
Please take a moment to review these points before you continue with the
next topic.
•
•
There are many types of gloves to protect your hands from many types
of hazards. The following are the most common types found in the
construction industry:
o Heat-resistant gloves
o Metal mesh gloves
o Rubber gloves
o Rubber, neoprene, and vinyl gloves
o Leather gloves
o Cotton fabric gloves
Use the following guidelines to protect your hands:
o Match the type of glove with the hazard it must protect against.
o Check for holes, scratches, and cracks.
o Check the color of the glove.
o Check the elasticity of the glove.
o Check the thickness of the glove.
o Make sure the glove fits properly.
Topic 6: Eye Protection
You learned about hand protection in the previous topic. In this topic you will
learn about eye protection in detail. OSHA requires that workers be protected
from hazards to the eyes by wearing eye protection where there is a hazard of
flying particles, chemicals, or potentially dangerous light radiation.
Upon completing this topic, you should be able to:
•
•
•
Summarize typical hazards requiring eye protection equipment
Explain types of eye protection devices
Use and care for eye protection equipment
Typical Hazards Requiring Eye Protection Equipment
Eye protection should protect you from:
•
•
•
•
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Flying particles
Molten metal
Liquid chemicals
Acid and caustic substances
Chemical gases or vapors
Light ray radiation
No matter what job is being performed on a construction site, the eyes will be
exposed to a variety of hazards. Dust and flying particles are very common on
the site. Drilling, chipping, and hammering are some of the most routine tasks
that can result in potentially harmful, flying objects.
Chemicals and radiation are also common on a site and pose a very different
hazard. Acids, hot tar, and molten metal can splash into the face or eyes and
cause severe damage.
Radiation hazards also are common to the industry. Every time an arc is
generated, intense light waves are given off. These waves, along with the
sparks and molten metal, can rob you of your sight. Welding helmets and face
shields must be used for protection. The intensity of the light can burn the
eyes and, if the exposure is great enough, cause blindness.
Eye Protection Devices
There are four types of eye and face protection devices: safety glasses, safety
goggles, face shields, and welding helmets. Each type of eye protection is
designed to provide protection against a particular hazard. They also are
classified as Primary or Secondary protectors.
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•
A primary protector is a device that may be worn alone or with a
secondary protector. Examples of primary protectors include safety
glasses and goggles.
A secondary protector is a device that must be worn with a primary
protector. Examples of secondary protectors are face shields and
welding helmets.
Key Point: Secondary protectors should not be used unless you are also
wearing a primary protector. Always wear safety glasses or goggles when
using face shields or welding helmets.
Safety Glasses (Primary Protectors)
Safety glasses shield your eyes from a variety of hazards. They are commonly
used to protect against impact and optical radiation. Lenses on safety glasses
are available in clear, filtered, or tinted materials and flat or curved design.
The lenses in some spectacles are removable and can be replaced easily.
Some safety glasses have side shields to provide protection to the eyes from
hazards that are encountered at an angle. Most eye injuries that occur while
wearing eye protection are due to poor angular protection. Side shields should
be used whenever practical.
Safety Goggles (Primary Protectors)
Goggles are intended to fit the area of the face surrounding the eyes and
shield the eyes from a variety of hazards. Goggles are generally classified as
"eye cup" or "cover."
Eye cup goggles are designed to cover the eye socket completely. Cover
goggles cover the outside border of the eyes and may be worn over
spectacles. Like spectacles, goggles are available in clear, filtered, or tinted
materials. Some styles have removable lenses that can be easily replaced.
Special coatings are applied to some lenses to reduce fogging, scratching, and
corrosion.
Face Shields (Secondary Protectors)
Face shields are protective devices intended to shield your face and eyes. Face
shields should be used only with primary protectors. Special purpose face
shields are available to provide a range of protection. They may be made of
many materials including wire screen and clear or tinted plastic.
Welding Helmets (Secondary Protectors)
Welding helmets shield the eyes and face from optical radiation and impact.
They should be used with primary protectors. The three major classifications
of welding helmets are stationary front, lift front, and hand shields.
Welding helmets are usually made from fiberglass and thermal molded plastic.
Specials coatings, materials, and headgear make modern welding helmets
lighter, cooler, and more comfortable.
Care and Use of Eye Protection Devices
Most eye protection (safety glasses and face shields) is rated to absorb one
serious impact. If your eye protection has done its job and provided this
protection, then it is time to replace it. Likewise, any type of eye protection
that is scratched or is difficult to see through creates another hazard by
limiting your field of vision. It is important to treat your eye protection with
care by storing it in a location where it is protected from being soiled or
damaged.
The eye protection selected must be suitable for the work to be performed.
These rules apply to supervisors, management personnel, and any visitors
while they are in hazardous areas.
Checklist for Eye Protection Devices
Please remember the following checklist before and when you wear eye
protection devices.
Evaluate the hazards to determine proper eye and face protection.
All protective devices should meet ANSI standards (Z87.1) and be
appropriately marked.
The lenses of protective prescription lenses worn by employees should
meet ANSI specifications and be appropriately marked.
The spectacles used should have side shields.
All protective devices should be fitted to the user.
The lenses of face shields and glasses should be free from scratches,
chips, and scrapes.
The elastic in headbands should be in good condition.
Headbands should be free of fraying, tears, or other worn parts.
All ratchet headbands should provide a snug fit.
All temple and face piece hinges should be in good condition.
Eye and face equipment should be kept in clean and sanitary condition.
Topic Summary
Please take a moment to review these points before you continue with the
next topic.
• Eye protection should protect you from:
o Flying particles
o Molten metal
o Liquid chemicals
o Acid and caustic substances
o Chemical gases or vapors
o Light ray radiation
• There are four types of eye and face protection devices:
o Safety glasses (primary protectors)
o Safety goggles (primary protectors)
o Face shields (secondary protectors)
o Welding helmets (secondary protectors)
• Eye protection should be properly cared for and stored in a location that
keeps it free from being scratched, soiled, or exposed to hazardous
elements (sun or chemicals).
Topic 7: Foot Protection
You learned about eye protection in the previous topic. In this topic you will
learn about foot protection in detail. The OSHA construction standards depend
on ANSI Z41, "American National Standard for Personal Protection-Protective
Footwear," to provide the specification for footwear. Footwear that is selected
based on the hazards present, and which has ANSI approval, will comply with
the OSHA standard.
Upon
•
•
•
completing this topic, you should be able to:
Summarize typical hazards requiring foot protection equipment
Describe types of foot protection devices
Use and care for foot protection equipment
Typical Hazards Requiring Foot Protection Equipment
Employees must use protective footwear when working in areas where there is
a danger of foot injuries due to falling or rolling objects, objects piercing the
sole, or electrical hazards.
The hazard most frequently thought of when safety shoes are mentioned is
heavy objects that fall or roll over the foot. However, hazards that involve the
foot and leg also include slippery or wet surfaces, sharp objects, hot surfaces
and materials, and electrical and chemical exposure.
Foot Protection Devices
With advances in technology, safety shoes and boots provide more than just
steel toe protection. In fact, many provide compression and impact resistance
without the use of a metal toecap. New styles of shoes can offer slip-resistant
protection and have electrical hazard protection while maintaining the
protection from compression from falling objects. With the number of styles
available, shoes can be selected that protect the foot from hot or cold
environments as well.
Electrical hazard shoes: Made to provide extra protection where incidental
contact with energized circuits is possible
Slip-resistant shoes: Have soles that increase friction with wet or otherwise
slippery surfaces to prevent falls
Other protective footwear (such as metatarsal and shin guards)
Can be used in conjunction with standard safety shoes
Safety boots: Protect from exposure to splash or spark hazards (chemicals,
molten materials)
Neoprene or nitrile boots: Used when working with corrosives, caustics,
cutting oils, and petroleum products to prevent penetration
Foundry or "Gaiter" style boots: Often used in welding operations; quickrelease fasteners or elasticized insets to allow speedy removal should any
hazardous substance get into the boot itself
Care and Use of Foot Protection Devices
The ANSI Protective Footwear Standard provides a guide for classifying the
performance characteristics of safety footwear. Every pair of approved safety
shoes should be stamped, usually on the inside lining, with its Z41
performance classification and identification.
Checklist for Foot Protection Devices
Please remember the following checklist before and when you wear foot
protection devices.
Shoes should be free of cracks in the soles.
All shoes should meet ANSI standards and be appropriately marked.
The soles should be free of metal or other objects that can become
imbedded in the sole or other portions of the shoe.
The upper portion of the sole should be free of tears, cracks, or loose
stitching.
The upper should be firmly attached to the sole.
The appropriate shoes should be worn for the task being performed.
Topic Summary
Please take a moment to review these points before you continue with the
next topic.
• The hazard most frequently thought of when safety shoes are mentioned
is heavy objects that fall or roll over the foot.
• There are many types of footwear to protect you from a variety of
hazards at your job site:
o Electrical hazard shoes
o Slip-resistant shoes
o Other protective footwear (such as metatarsal and shin guards)
o Safety boots (neoprene or nitrile boots, foundry or "Gaiter" style
boots)
Topic 8: Protective Clothing
You learned about foot protection in the previous topic. In this topic, you will
learn about protective clothing in detail. Defining personal protective clothing
is a difficult task. The OSHA construction standards do not provide detailed
requirements on personal protective clothing. However, failure to mandate
employees to wear shirts with long sleeves during certain operations has been
cited as a violation. For the purpose of this topic, protective clothing will refer
to full-body chemical protective suits and clothing or protective wear that
covers the general area of the torso.
Upon completing this topic, you should be able to:
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Summarize typical hazards requiring protective clothing
Describe types of protective clothing
Use and care for protective clothing
Typical Hazards Requiring Protective Clothing
The hazard assessment must consider all clothing that is necessary to perform
a job safely.
Chemical exposure that requires the use of full-body chemical protective suits
is less common, but it does occur. Contracts with chemical plants, refineries,
or other hazardous chemical processes can involve potential exposure to
chemicals that may splash onto all parts of the body. Many plants require all
employees to wear chemical-resistant coveralls just to perform a site
inspection. If the hazards are present, protection must be provided. The type
of coverall will depend on the chemical to which there is potential exposure.
Protective clothing also is necessary to protect workers from cuts and scrapes
from handling various building materials, tools, and equipment.
Radiation from the sun can cause painful skin conditions. The use of clothing
to protect workers from sunburn is often overlooked but very critical.
The construction standards identify the "criteria for personal protective
equipment," mandating that protective wear be "provided, used, and
maintained in a sanitary and reliable condition wherever it is necessary"
because of workplace hazards that could be "encountered in a manner capable
of causing injury or impairment in the function of any part of the body through
absorption, inhalation, or physical contact."
Protective Devices/Materials
Protective Devices
Special vests, aprons, and jackets are available to protect workers from
hazardous environments. The torso also can be used as the site for protective
gear needed to make others aware of your presence.
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Special vests: Night workers and flagmen who might be struck by
moving vehicles need suits or vests designed to reflect light (florescent
orange).
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Aprons: For protection from sparks and molten metal, welders should
use leather aprons.
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Jackets: Workers performing tasks over water need a Coast Guardapproved life jacket or buoyant work vest.
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Disposable suits: These may provide protection from dusty materials or
materials that can splash. If the substance is extremely toxic, a
completely enclosed suit may be necessary. The clothing should be
inspected to assure proper fit and function for continued protection.
Protective Materials
Some materials and fabrics are specifically designed to protect workers from
such hazards as heat, cold, splashes from hot metals and liquids, impacts,
cuts, acids, and radiation. The material must be selected to protect you from
the specific hazard.
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Wool and specially treated cotton are two natural fibers which are fireresistant and comfortable, since they adapt well to changing workplace
temperatures.
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Duck, a closely-woven cotton fabric, is good for light duty protection. It
can provide some protection against cuts and bruises on jobs where
employees handle heavy, sharp, or rough material.
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Heat-resistant clothing such as leather is often used to guard against dry
heat and flame.
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Rubber, rubberized fabrics, neoprene, and plastics give protection
against some acids and chemicals.
Care and Use of Protective Clothing
Employers are responsible for assuring the adequacy of the clothing, including
proper maintenance, and sanitation even when it is employee-owned. Clothing
that is exposed to hazardous chemicals, dusts, or any potential contaminants
should be cared for and cleaned separately from other clothing.
Checklist for Protective Clothing
Please remember the following checklist before and when you wear protective
clothing.
Protective clothing and equipment should meet OSHA and/or ANSI
requirements.
Affected workers should be given the opportunity to practice and
demonstrate their competence putting on and taking off the PPE before
entering the hazardous environment.
Clothing should be free of any holes, tears, or cracks.
Equipment for cleaning, maintaining, and storing protective equipment
should be made available.
Affected workers should be trained on:
Hazards in the workplace
When and where the use of protective clothing is required
Fit-testing protective clothing
Putting on protective clothing
Monitoring the effectiveness of protective clothing
Inspection of protective clothing
Procedures to follow if protective clothing fails
Storage of protective clothing
Maintenance of protective clothing
Limitations of protective clothing
Hazards encountered when using protective clothing
Topic Summary
Please take a moment to review these points before you continue with the
next topic.
• Contracts with chemical plants, refineries, or other hazardous chemical
processes can involve potential exposure to chemicals that may splash
onto all parts of the body.
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Protective devices include:
o Special vests (night workers and flagmen)
o Aprons (sparks and molten metal, welders)
o Jackets (tasks over water
o Disposable suits (dusty materials or materials that can splash)
Protective materials include:
o Wool
o Duck (cuts and bruises on jobs)
o Heat-resistant clothing (dry heat and flame)
o Rubber, rubberized fabrics, neoprene, and plastics (acids and
chemicals).
Clothing that is exposed to hazardous chemicals, dusts, or any potential
contaminants should be cared for and cleaned separately from other
clothing.
Topic 9: Respiratory Protection
You learned about protective clothing in the previous topic. In this topic you
will learn about respiratory protection in detail. Any operation that generates
harmful airborne levels of dusts, fumes, sprays, mists, fogs, smokes, vapors,
or gases or that may involve oxygen-deficient atmospheres requires the use of
effective safety controls.
This must be accomplished, as much as feasible, by accepted engineering
control measures (for example, enclosure or confinement of the operation,
general and local ventilation, and substitution of less toxic materials).
When effective engineering controls are not feasible, or while they are being
instituted, appropriate respiratory protection must be used.
Upon
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completing this topic, you should be able to:
Summarize typical hazards requiring respiratory protection equipment
Describe the types of respirators
Explain three basic steps in selecting respiratory equipment
Use and care for respirators
Recall your responsibilities when you wear a respirator
Typical Hazards Requiring Respiratory Protection
Construction employees can be exposed to a variety of respiratory hazards
that include vapors, fumes, and particles. Welding operations release gases
and fumes filled with metals and other toxins. The solvents used in many
operations give off harmful vapors. Also, particles are released as dust is
generated during grinding operations and placement of insulation materials
such as fiberglass.
What types of hazards require respiratory protection:
Gaseous Contaminants
Gaseous contaminants add harmful, invisible gases or vapors to the air.
Chemicals can be gases at room temperature but become solids or liquids at
low temperatures or high pressure. Carbon dioxide is a gas at room
temperature. At low temperatures it becomes solid dry ice. Under pressure in
cylinders it is a liquid. Vapors are like gases except that they are formed by
the evaporation of liquid substances. Examples include acetone and
trichloroethylene, which ordinarily exist as liquids.
Particulate Contaminants
Particulate contaminants are tiny particles or droplets of hazardous material in
the air. They are classified as dusts, mists, and fumes. Dusts are solid and can
be created by grinding, crushing, sanding, or mixing operations. Examples
include sand and plaster dust. Mists are liquid droplets and are given off by
the spraying or mixing of liquids. Fumes are very small metal particles given
off as metals are heated. Welding, brazing, soldering, and other molten metal
processes produce fumes.
Note: Gaseous and particulate contaminants often occur together. Spray
painting operations produce particulates in the form of paint mists and
solvent vapors that are gaseous contaminants.
Atmospheres Immediately Dangerous to Life or Health (IDLH)
IDLH are conditions that can result in severe injury or death in a short time or
have serious delayed effects. Carbon monoxide or hydrogen sulfide exposures
can result in death even within a short period. Radioactive materials or cancercausing chemicals can have serious delayed effects.
Oxygen-Deficient Atmospheres
Oxygen-deficient atmospheres are areas that do not have a safe level of
oxygen in the air. These areas are classified as Immediately Dangerous to Life
or Health (IDLH). However, not all IDLH are oxygen-deficient atmospheres
(e.g., radioactive materials or cancer-causing chemicals). Exposure to these
atmospheres can cause brain damage and death. Low levels of oxygen are
frequently found in confined and poorly ventilated spaces such as silos and
storage tanks. Oxygen can be used up by chemical reactions or moved away
by other gases when leaks occur. Fire is a common chemical reaction that uses
up oxygen.
Types of Respirators
There are two kinds of respirators.
Atmosphere-supplying respirators:
• Atmosphere-supplying respirators are designed to provide breathable air
from a clean, supplied air source.
• These are suitable for oxygen-deficient atmospheres.
• These types of respirators range from self-contained breathing
apparatus (SCBA) and supplied air respirators (SARs) to complete air
supplied respirators.
Air-purifying respirators:
• Air-purifying respirators use filters to remove hazardous substances
from the air you breathe.
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They range from simple, disposable masks to powered air-purifying
devices.
These respirators do not supply oxygen and may not be used in oxygendeficient atmospheres.
Selecting Respiratory Equipment
Respiratory protection should be selected using three basic steps:
Step 1 - Identify the Hazard
The proper selection and use of respirators is deadly serious business. There
are many different types of airborne hazards. Each respirator is designed to
protect you against a specific hazard. Thus it is critical that you select the
correct respirator. The wrong respirator will not protect you.
For this reason it is vital to first identify the type of hazard that is present.
There are many types of hazards that require respirators, such as harmful
dusts, fumes, gases, or oxygen-deficient atmospheres. The type of hazard
present will determine the proper respirator.
Step 2 - Evaluate the Hazard
Employers must conduct a hazard evaluation by reviewing employee groups,
processes, or environments that may require the use of respirators. You need
special methods and instruments to measure the level of airborne
contaminants and trained and qualified technicians to use this testing
equipment and interpret the results.
Material Safety Data Sheets (MSDS) are a great tool in identifying respiratory
hazards found in the substances used on the job. MSDSs can help identify the
exposure limits as well as the proper respiratory protection needed.
Step 3 - Select the Proper Respirator
After the respiratory hazards have been recognized and measured, employers
must also consider such things as:
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Is the identified hazard the only hazard present?
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Does the hazard have adequate warning properties such as an odor,
taste, or irritation that would alert the worker to its presence?
Will the hazard harm or irritate the eyes?
Can the hazard be absorbed through the skin and injure the worker?
Once you have considered all the factors, you select the type of respirator.
Choosing the right respirator protection equipment involves several steps:
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Determining what the hazard is and its concentration
Choosing equipment that is certified for the function and assuring the
device is performing the intended function
The form of the hazard (vapor, particle, etc.)
OSHA requires that only approved respirators be used. An approved respirator
is one that has been tested by the National Institute of Occupational Safety
and Health (NIOSH) and the Mine Safety and Health Administration (MSHA).
Care and Use of Respirators
Respirators must be properly cleaned, inspected, stored, and in good repair if
they are expected to work properly.
Cleaning
At the end of each work shift, the respirator should be cleaned and disinfected.
If the respirator is shared with other employees, it should be cleaned and
disinfected between users.
Follow the manufacturer's instructions for cleaning and disinfecting all
respirators. Ask a supervisor if you are not sure how to clean and disinfect
your respirator.
Inspection
Inspect your respirator before and after each use. These inspections will help
prevent you from using a damaged respirator. A damaged respirator may not
properly protect you from the harmful chemicals.
Follow the manufacturer's instructions for inspecting your respirator. Ask your
supervisor if you are not sure what steps to take to inspect your respirator.
Never attempt to use a damaged respirator. Report damaged respirators to
your supervisor.
Storage
Respirators are to be stored in a convenient and clean location. The law
requires that respirators be protected from dust, sunlight, heat, extreme cold,
excessive moisture, and damaging or contaminating chemicals.
You should never place objects on your respirator or place it in positions that
would cause the sealing surfaces to distort or bend out of shape.
Always handle your respirator with care. Follow the manufacturer's
instructions for storing your respirator. Ask your supervisor if you are not sure
how your respirator should be properly stored.
Repair
Sooner or later your respirator will need repair. The law requires that people
who repair respirators be well trained. Replacement parts must come from the
manufacturer of the respirator.
The NIOSH approval of the respirator is not valid if parts from a different
manufacturer are used. The respirator may appear to work just as well with
the substitute parts, but they should NEVER BE USED.
Key Point: Each of you who is required to wear a respirator has certain
responsibilities.
Checklist for Disposable Respirators
Please remember the following checklist before and when you wear a
respirator.
The respirator should be free of holes or tears.
The strap should still have its elasticity.
The metal nose clip should allow for a proper fit.
Checklist for Air-Purifying Respirators
The face piece should have its original form, allowing a proper fit.
The face piece should be free of cracks or tears.
The face piece should be clean.
The head strap's elastic should be free of tears and broken buckles.
The exhalation valve should be clean.
The exhalation and inhalation parts should be free of cracks, tears, or
distortion.
The proper filter should be used.
Checklist for Atmosphere-Supplying Respirators
The face piece should have its original form, allowing a proper fit.
The face piece should be free of cracks or tears.
The face piece should be clean.
The head strap's elastic should be free of tears and broken buckles.
The exhalation valve should be clean.
The exhalation and inhalation parts should be free of cracks, tears, or
distortion.
The air quality provided by the compressor or other device should be
breathable.
All connections should be tight.
The regulators should be set according to the manufacturer's
specifications.
The hoses should be free of kinks, tears, or cracks.
If a hood or helmet is used, the:
• Suspension should be adjusted for the wearer
• Face shield should be free of cracks or breaks
Lesson Summary
This lesson contains information and instruction about personal protective
equipment (PPE). By completing this lesson, you should have the knowledge
to discuss the topics below. Take a moment to see if you can do the following:
• Identify the types of hazards requiring PPE, including impact,
penetration, compression, chemical/harmful dust, temperature,
light/radiation, noise, and electrical
• List the types of PPE
• Describe why you must wear PPE
• Distinguish typical hazards and types of protection devices, and apply
how to care and use of:
o Head protection
o Hearing protection
o Hand protection
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Eye protection
Foot protection
Protective clothing
Respiratory protection
Fire Protection and Prevention
Introduction
Every 45 seconds in the United States, someone's home catches on fire. There
is a fire-related death every two hours. The United States has the highest
death rate from fires of any industrialized country. The National Fire Protection
Association estimates that more than 3,500 lives are lost to fires each year
and more than 21,000 persons suffer injuries.
Workplace fires and explosions kill over 200 and injure more than 5,000
workers each year. In 1995, more than 75,000 workplace fires cost businesses
more than $2.3 billion. Fire in the workplace is one of the most significant
hazards to employees' lives and health. It can strike any workplace.
The effects of workplace fires are devastating to employees and employers.
Many workers bear the emotional and physical pain from injuries and families
suffer from their loss. Many businesses are destroyed each year due to heavy
financial loss as well.
OSHA recognizes the serious nature of workplace fires and has set many
standards and developed many programs for workplace fire protection and
prevention.
Lesson Overview
This lesson examines fire, one of the most significant hazards in any
workplace. In this lesson, the student will learn about the basic elements of
fire, the causes and hazards associated with fire, and how to control and
prevent fire. They will learn more about different types of fire extinguishers.
Upon
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completing this lesson, the student will be able to:
Explain the essential elements of fires and list four types of fuel sources
Identify seven common hazards associated with fire
Describe the proper control mechanisms associated with using and
handling the following: electrical equipment, welding, fueling and
refueling, storage, heating device, and LPG
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Describe the proper handling of flammable or combustible liquids
including the storage requirements, the transferring requirements, and
the requirements of use
Discuss four different types of fire extinguishers for different types of
fires and their ratings
Discuss four different types of fire extinguishers based on the fireextinguishing agents used
Describe the step-by-step process of using fire extinguishers
Differentiate between an FPP and an EAP
List situations when you shouldn't fight the fire
Click the forward arrow in the upper-right corner of the window or the
items on the left navigation bar to continue.
Why Learn This Lesson?
Historically, workplace fires have been a leading cause of worker death and
injury. These fire losses exact a toll in emotional trauma and financial hardship
on families. However, most of these fires can be controlled or prevented. Fire
safety should be everyone's job at a worksite. As an employee, you are
responsible for your own safety as well as for the safety of your co-workers.
The information contained in this lesson will increase your knowledge of
potential fire hazards and the proper handling of the equipment and materials
most likely to cause fire. It also will teach you about fire extinguishers and
how to use them. Finally, it will help you in setting up proper fire prevention
plans and emergency action plans.
Topic 1: General Information
This topic introduces general information about OSHA's fire protection
standards.
History of Workplace Fires
The fire at the Triangle Shirtwaist Factory in New York City in 1911 was one of
the most notable fires. Nearly 150 women and young girls died because of
locked fire exits and inadequate fire extinguishing systems.
History repeated itself in 1991 with the fire in Hamlet, North Carolina, where
25 workers died and 54 were injured in a fire in a poultry processing plant.
There were problems with fire exits and fire extinguishing systems in this
incident too.
The Ybor City Apartment Complex fire in Florida is believed to have been
caused by a broken 7,620-volt power line struck by a forklift arm. The wire
landed on some construction debris and then set a palm tree on fire. The
building in the apartment complex had no wallboard or firewall protection up
yet and that allowed flames to spread quickly. The fire eventually claimed the
apartment complex, a nearby post office, a tobacco warehouse, a church
building and a few other buildings. The fire resulted in over $120 millions in
property damage and 5 injuries.
The Old Cotton Mill fire in Atlanta fire is said to have been started by a welding
spark that caught a pile of trash on the fourth floor of a chicken processing
plant. The five-story brick and wood structure built in the 1880's was being
renovated as part of a three-phase project. The old mill was being renovated
into residential lofts. Due to the winds and the dry conditions in Atlanta, three
adjacent houses caught on fire as well. The insurance carrier estimated the
fire damage in excess of $10 million.
OSHA Fire Safety Standards
Statistics show that fire has a major impact on our lives at work and at home.
For that reason, an integrated structure of fire safety institutions and
regulations by local, state, and federal government agencies is in place to
prevent workplace fires. OSHA fire safety standards are an important element
of the total complex of public policies affecting fire safety.
OSHA standards establish minimum requirements for fire prevention, for
workplace evacuation in the event of fire, and for protection of workers who
may become involved in firefighting in the workplace.
Responsibilities
The employer is responsible for the development and maintenance of an
effective fire protection and prevention program at the job site, including the
availability of the fire protection and suppression equipment.
It is the responsibility of each employee to comply with all applicable OSHA
standards and to follow all employer safety and health rules and policies.
Topic Summary
Please take a moment to review these major points before you continue with
the next topic.
• The Ybor City Apartment Complex fire in Tampa, Florida, and the Old
Cotton Mill fire in Atlanta, Georgia, are two recent construction fires.
• An integrated structure of fire safety standards and regulations by local,
state, and federal government agencies is in place to supervise
workplace fire safety.
• OSHA standards establish minimum requirements for fire prevention, for
workplace evacuation in the event of fire, and for protection of workers
who may become involved in firefighting in the workplace.
• According to a recent OSHA research study, among the 100 most cited
standards, fire-related standards accounted for 3 percent.
• The employer is responsible for the development and maintenance of an
effective fire protection and prevention program at the job site, including
the availability of the fire protection and suppression equipment.
Topic 2: Fire Basics
This topic teaches the basic elements of fires, the types of fuel sources, and
common terminologies of fires.
Essential Elements of Fires
Do you know what a fire needs in order to burn?
Fire needs three elements in order to burn. They are fuel, heat, and oxygen.
Move your cursor over each element to see a short description of each.
Fuel: anything that will burn -- solid, liquid, or gas. Sources of fuel may
include paper, wood, flammable gases, and combustible liquids.
Heat: the energy needed to increase the temperature of the fuel to its ignition
temperature. Sources of heat may include cutting, grinding, roofing, and
welding operations.
Oxygen: needed to accelerate combustion. Fire needs about 16 percent
oxygen to sustain the rate of combustion. The air we breathe is about 21
percent oxygen.
In recent years, this fire triangle concept has been expanded to include a
fourth element, that of the chemical reaction, thus creating the fire
tetrahedron.
Note: Essentially, the process of fire is a chemical reaction that involves
the rapid oxidation or burning of a combustible material. The technical
term for this combustion process is chemical chain reaction or
exothermic reaction.
Types of Fuel Sources
There are many different types of fuel sources. Do you know how to classify
them?
They can be classified into four groups:
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Class A includes ordinary solids like paper, wood, trash, scrap lumber,
cloth, rubber, and some plastics, but no metals. This fuel source will
leave an ash.
Class B includes flammable liquids like gasoline, oil, grease, acetone,
solvents paints, propane, and any nonmetal in a liquid state. This fuel
source usually will boil.
Class C involves electrical fires that are energized by electrical
equipment, motors, cords, temporary power and switchgears. This fuel
source comes from a current or circuit.
Class D includes combustible metals like sodium, aluminum, magnesium,
and potassium.
Topic Summary
Please take a moment to review these major points before you continue with
the next topic.
• Fire needs three elements in order to burn. They are fuel, heat, and
oxygen. This is commonly known as the fire triangle.
• There are four distinct fuel classifications:
o Class A includes ordinary solids like paper, wood, trash, scrap
lumber, cloth, rubber, and some plastics.
o Class B includes flammable liquids like gasoline, oil, grease,
acetone, solvents, paints, propane, and any nonmetal in a liquid
state. This fuel source usually will boil.
o Class C involves electrical fires that are energized by electrical
equipment, motors, and switchgears.
o Class D includes combustible metals like sodium, aluminum,
magnesium and potassium.
Topic 3: Fire Hazards and Prevention
Many hazards are associated with fires. Some common ones are electrical
equipment, welding operations, smoking, fueling and refueling, storage,
heating devices, and liquid petroleum gas (LPG).
Common Hazards
Electrical Equipment
Electrical systems and equipment, including wiring, cords and switches, are
major sources of fire ignition sparks or heating hazards. Overloaded,
damaged, or flawed electrical circuits generate heat in wiring that can reach a
temperature capable of igniting flammable materials.
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Only approved electrical equipment should be used in flammable areas.
A qualified individual should inspect all electrical equipment including
switches, outlets, boxes, and panels for frayed, broken components or
other damage.
All electrical cords should be inspected for cuts or abrasions that could
alter the integrity of the equipment.
All electrical tools should be inspected for damage that could make the
tools hazardous.
Welding Operations
Welding, cutting, and grinding operations can produce sparks that can ignite
materials, gases, or flammable liquids in the work area. Open containers of
flammable liquids can generate gases that may accumulate, and when they
reach a flame or spark they can cause explosive ignition that leads back to the
flammable liquid source.
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Welding, cutting, and grinding operations that could create a spark
should be completed 30 minutes prior to the end of the work shift.
You also should use a welding curtain or screen and post a fire watch to
monitor the area for fire.
You should inspect the area where you are welding, cutting, or grinding
before you start work.
You always should keep your area clean of debris.
Smoking
Uncontrolled smoking and careless disposal of used cigarettes or other tobacco
products is a major hazard and the cause of many workplace fires.
Fueling and Refueling
Flammable and combustible liquids used in service areas for fueling vehicles
and equipment can be spilled and create an ignition source for fires.
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There should be no smoking or open flames in the areas used for
fueling, servicing fuel systems, or receiving or dispensing flammable or
combustible liquids. Conspicuous and legible signs prohibiting smoking
should be posted in these areas.
The motors of all equipment being fueled must be shut off during the
fueling operation.
Each service or fueling area should be provided with at least one fire
extinguisher having a rating of not less than 20-BC. Extinguishers should
be located so that an extinguisher will be within 75 feet of each pump,
dispenser, underground fill pipe opening, and lubrication or service area.
Flammable liquids must be stored in approved safety cans with springclosing lids and a flame arrestor. Approved containers have a laboratory
listing or label recognized by OSHA.
Always inspect the area for potential fire hazards and always keep the
area free of debris that can be a fuel source for fire.
Storage Areas
Many of the building materials used on the construction site are flammable
and pose a hazard should a fire occur. Areas where materials are stored
provide a good source of fuel for a fire.
The following are specific safety requirements for open yard storage:
• Combustible materials should be piled to ensure stability and in no case
higher than 20 feet.
• All driveways near combustible storage piles should be at least 15 feet
wide and be free of accumulation of rubbish, equipment, or other articles
or materials.
• The entire storage site should be free of accumulation of unnecessary,
combustible materials.
• Combustible materials should not be stored outdoors within 10 feet of a
building or structure.
• Portable fire extinguishing equipment, suitable for the fire hazard
involved, should be provided at convenient, conspicuously accessible
locations.
• Portable fire extinguishers, rated not less than 2A, should be placed so
that maximum travel distance to the nearest extinguisher is not more
than 100 feet.
The following are specific safety requirements for indoor storage:
• Storage should not obstruct any exits.
• All materials should be stored, handled, and piled with due regard to
their fire characteristics.
• A barrier having a fire resistance rating of at least 1 hour should
segregate noncompatible materials that could create a fire hazard.
• Aisle space should be maintained to safely accommodate the widest
vehicle that would be used within the building for firefighting purposes.
• There should be a clearance of at least 36 inches between the top level
of the stored material and the sprinkler deflectors.
• Clearance must be maintained around lights and heating units to
prevent the ignition of combustible materials.
• There should be a clearance of 24 inches around the path of travel of fire
doors unless a barricade is provided.
• Material should not be stored within 36 inches of a fire door opening.
Heating Devices
Temporary heating devices also need special care to avoid or control the
hazards associated with their use. Fire ignition hazards include open flames,
some chemical agents, sparks, and heat-producing equipment or materials.
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Inspect the surrounding area before you start any heating device and
always consider housekeeping to prevent debris from building up around
any heating devices.
When temporary heaters are used, fresh air should be supplied to
maintain the health and safety of workers.
If there is not an adequate natural supply of fresh air, then mechanical
ventilation must be provided.
When heaters are used in confined spaces, special care must be taken to
provide sufficient ventilation that:
o Ensures proper combustion of the heater
o Maintains the health and safety of workers
o Limits temperature increases in the area
Key Point: Solid fuel salamanders are prohibited in buildings and on
scaffolds.
Key Point: Flammable liquid-fired heaters must be equipped with a
primary safety control to stop the flow of fuel in the event of flame
failure.
Liquid Petroleum Gas (LPG)
Liquid petroleum gas (LPG) is not in widespread use but still seen on some
construction sites. It is a highly flammable material and poses a serious fire
hazard.
•
•
•
•
•
Liquid petroleum gas (LPG), although not in widespread use on
construction sites, poses a serious fire hazard.
When LPG is being used, the following safety requirements must be
followed:
Each system should have approved containers, valves, connectors,
manifold valve assemblies, and regulators, and all cylinders must meet
the Department of Transportation specification identification
requirements published in 49 CFR Part 178, Shipping Container
Specifications.
Welding is prohibited on containers.
Connections to containers, except safety relief connections, liquid-level
gauging devices, and plugged openings, should have shutoff valves
located as close to the container as possible.
•
•
•
•
Every container and every vaporizer should be provided with one or
more approved safety relief valves or devices.
Storage of LPG within buildings is prohibited.
Containers should be in a suitable, ventilated enclosure or otherwise
protected against tampering.
Precautions should be taken to eliminate the risk of damage to LP gas
systems by vehicular traffic.
Other Prevention Methods
In addition to specific control mechanisms associated with using equipment,
storage, and materials, there are other methods for fire control and
prevention:
• Housekeeping
• Inspection
• Using MSDS
• Hazard communication training
Housekeeping
Fire prevention involves the elimination or control of conditions or substances
that could ignite or fuel a fire. Maintaining a clean and orderly workplace is an
essential element of fire prevention. As part of the program, preplanning for
trash and rubbish removal is an important part of preventing fire hazards.
Removing accumulations of Class A waste materials such as paper, cardboard,
wood pallets, packing materials, and trash from the work area will help
minimize unwanted fires.
Inspection
Every employer should routinely inspect the workplace to identify fire ignition
and fuel hazards and then take appropriate steps to eliminate them. Certain
materials generate heat from inherent chemical decomposition processes and
if accumulated to critical mass can generate enough internal heat to
spontaneously combust. Sawdust debris accumulations, oily rags in open
containers, and fuel storage areas are particularly susceptible to spontaneous
combustion.
Using MSDS
Material safety data sheets (MSDS) from your supplier can help you determine
which materials are flammable and which are only combustible or will not
burn. Also, the MSDS will tell you which fire extinguishing agent is effective on
the specific material if it were to catch fire. This is most important to those
contractors that work with easily ignitable materials such as flammable liquids
and gases and those that use equipment that depends on liquid or gaseous
fuels.
Hazard Communication Training
Hazard communication training is required by OSHA and, as part of the
training, advises you on the proper use of a material safety data sheet.
Topic Summary
Please take a moment to review these key points before you continue with the
next topic.
• There are seven fire hazards that are common in the workplace. They
are:
o Electrical Equipment - Electrical systems and equipment, including
wiring, cords, and switches, are major sources of fire ignition
sparks or heating hazards.
o Welding Operations - Welding, cutting, and grinding operations can
produce sparks that can ignite materials, gases, or flammable
liquids in the work area.
o Smoking - Uncontrolled smoking and careless disposal of used
cigarettes or other tobacco products are major hazards and the
causes of many workplace fires.
o Fueling and Refueling - Flammable and combustible liquids used in
service areas for fueling vehicles and equipment can be spilled and
create an ignition source for fires.
o Storage Areas - Areas where materials are stored provide a source
of fuel for a fire.
o Heating Devices - Temporary heating devices also need special
care to avoid or control the hazards associated with their use.
o Liquid Petroleum Gas (LPG) - Liquid petroleum gas (LPG) is a
common hazard on the construction site and poses a serious fire
hazard.
• In addition to specific control mechanisms associated with using
equipment, storage, and materials, there are other methods for fire
control and prevention:
o Housekeeping
o Inspection
o Using MSDS
o Hazard communication training
Topic 4: Handling Flammable or Combustible Liquids
Flammable/combustible liquids are prevalent in construction sites. Gasoline,
for instance, is everywhere. This topic addresses the handling of flammable or
combustible liquids in detail.
Storage of Flammable/Combustible Liquids
The following requirements are for the storage of flammable and combustible
liquids on the job site in general:
• Use only approved containers and portable tanks for the storage and
handling of flammable and combustible liquids.
• Metal safety cans are the appropriate container for the handling and use
of flammable liquids in quantities greater than one gallon. For quantities
of less than one gallon, flammable liquid materials that are highly viscid
(extremely hard to pour) may be used and handled in their original
shipping containers.
• Flammable or combustible liquids are not to be stored in the areas on
the job site that are used for exits, stairways, or normally used for the
safe passage of people.
• At least one portable fire extinguisher, with a minimum rating of 20-B,
should be located within 10 feet of the entrance into any room used for
the storage of more than 60 gallons of flammable or combustible liquids.
Transferring Flammable/Combustible Liquids
The following requirements apply to the areas where flammable or
combustible liquids are transferred to other containers:
•
•
•
The areas where flammable or combustible liquids are transferred in
quantities greater than 5 gallons from one container to another need to
at least 25 feet away from all other operations.
Drainage or other means should be provided to control spills.
Adequate natural or mechanical ventilation must be provided to prevent
the buildup of flammable vapors.
•
•
•
•
•
Transfer of flammable liquids from one container to another can be
performed only when the containers are electrically interconnected
(bonded).
Transferring flammable or combustible materials by means of air
pressure is prohibited.
The dispensing units for flammable or combustible liquids must be
protected against collision damage.
Dispensing devices and nozzles for flammable liquids need to be of the
approved type.
At least one portable fire extinguisher with a minimum rating of 20-B:C
should be provided on all tank trucks or other vehicles used for
transporting and/or dispensing flammable or combustible liquids.
Use of Flammable and Combustible Liquids
The following requirements apply to the handling of these liquids at the point
of their final use on the job site:
• Flammable liquids should be kept in closed containers when they are not
actually in use.
• Any leakage or spillage of flammable or combustible liquids needs to be
disposed of promptly and safely.
• Flammable liquids may be used only where there are no open flames or
other sources of ignition a minimum of 50 feet from the operation.
Topic Summary
Please take a moment to review these major points before you continue with
the next topic.
• Flammable/combustible liquids are prevalent in construction sites. It Is
critical to follow safety practices to handle these flammable/combustible
liquids.
• Important requirements for flammable/combustible liquids storage:
o Only approved containers such as metal safety cans and, in some
cases, the original shipping containers can be used for the storage
of flammable and combustible liquids.
o Flammable or combustible liquids cannot be stored at exits,
stairways, or places normally used for the safe passage of people.
•
•
•
Important requirements for transferring flammable or combustible
liquids to other containers:
o The transferring operation should be conducted at least 25 feet
away from all other operations.
o Transfer of flammable liquids from one container to another can be
performed only when the containers are electrically interconnected
(bonded).
o Drainage or other means should be provided to control spills.
Adequate natural or mechanical ventilation must be provided to
prevent the buildup of flammable vapors.
Important requirements for using flammable or combustible liquids:
o Flammable liquids should be kept in closed containers when they
are not actually in use.
o Any leakage or spillage of flammable or combustible liquids needs
to be disposed of promptly and safely.
o Flammable liquids may be used only where there are no open
flames or other sources of ignition a minimum of 50 feet from the
operation.
A fire extinguisher that meets the minimum rating requirements needs
to be in place in all above situations.
Topic 5: Fire Extinguishers
This topic reviews the types and ratings of fire extinguishers and teaches you
how to use them.
Types of Fire Extinguishers
There are basically four different types or classes of fire extinguishers, each of
which extinguishes specific types of fires. Do you still remember the types of
fuel you learned about in the previous topic? There is a direct link between
types of fires and types of fire extinguishers.
•
•
•
Class A extinguishers will put out fires in ordinary combustibles, such as
wood and paper.
Class B extinguishers should be used on fires involving flammable
liquids, such as grease, gasoline, oil, etc.
Class C extinguishers are suitable for use on electrically energized fires.
•
Class D extinguishers are designed for use on flammable metals and are
often specific to the type of metal in question. Check the extinguisher
faceplate for the unit's effectiveness on specific metals.
Ratings of Fire Extinguishers
Class A and Class B fire extinguishers have a numerical rating which is based
on tests conducted by Underwriter's Laboratories (UL) that are designed to
determine the extinguishing potential for each size and type of extinguisher.
Class C extinguishers have only a letter rating. Class D extinguishers do not
have a numerical rating either and their effectiveness is described on the
extinguisher faceplate.
Class A Extinguishers Rating
The numerical rating for this class of fire extinguisher refers to the amount of
water the fire extinguisher holds and the amount of fire it will extinguish. An
extinguisher for Class A fires could have any one of the following ratings: 1-A,
2-A, 3-A, 4-A, 6-A, 10-A, 20-A, 30-A and 40-A. The bigger the size, the
greater the volume of extinguishing agent it has.
Class B Extinguishers Rating
The numerical rating for this class of fire extinguisher states the approximate
number of square feet of a flammable liquid fire that a non-expert person can
expect to extinguish. An extinguisher for Class B fires could have any of the
following ratings: 1-B, 2-B, 5-B, 10-B, 20-B, 30-B, 40-B, and up to 640-B.
Class C Extinguishers Rating
This class of fire extinguishers does not have a numerical rating. The presence
of the letter C indicates that the extinguishing agent is nonconductive. No
extinguisher gets a Class C rating without also having a Class A or Class B
rating. For example, you will see ratings of 1-BC, 2-BC, 5-BC or 1-AC, 2-AC,
3-AC.
Class D Extinguishers Rating
These extinguishers generally have no rating; nor are they given a
multipurpose rating for use on other types of fires. Their effectiveness is
described on the extinguisher faceplate.
Note: Multi-Class Ratings: Many extinguishers available today can be
used on different types of fires and will be labeled with more than one
designator, e.g., A-B, B-C, or A-B-C. Make sure that if you have a
multipurpose extinguisher it is properly labeled.
Different Fire Extinguishing Agents
You just learned about the types of fire extinguishers based on the types of
fire they are designed to put out. Another classification is based on the types
of extinguishing agents used. Based on this classification system, there are
four common types of fire extinguishers.
Dry Chemical Extinguishers
Dry chemical extinguishers are usually rated for multipurpose use. Those
labeled ABC are designed to extinguish Class A, B, and C fires. Those labeled
BC are designed to extinguish Class B and C fires.
Dry chemical extinguishers contain an extinguishing agent and use a
compressed, nonflammable gas as a propellant. They are effective in reducing
the fuel element and the chemical chain (or exothermic) reaction element of
the fire tetrahedron. The powder or chemical that is released from the
extinguisher coats the fuel source and interrupts the chemical chain (or
exothermic) reaction.
Note: Keep in mind, however, that dry chemical extinguishers can
reduce visibility and leave a residue that may cause irritation.
Halon Extinguishers
Halon extinguishers contain a gas that interrupts the chemical reaction that
takes place when fuels burn. These types of extinguishers are often used to
protect valuable electrical equipment since they leave no residue to clean up.
Halon extinguishers have a limited range, usually 4 to 6 feet.
Water Extinguishers
Water extinguishers contain water and compressed gas and should be used
only on Class A (ordinary combustibles) fires. A water extinguisher is an
effective, inexpensive, and nontoxic means of reducing the heat element of
the fire tetrahedron.
Note: Water extinguishers should be used only on Class A fires because
water can spread flammable liquid and is a good conductor that can
electrocute the individual using a water extinguisher on an electrical fire.
Water can also freeze.
Carbon Dioxide (CO2) Extinguishers
Carbon Dioxide (CO2) extinguishers are most effective on Class B and C
(liquids and electrical) fires. Since the gas disperses quickly, these
extinguishers are effective only from 3 to 8 feet. The carbon dioxide is stored
as a nonflammable compressed liquid in the extinguisher; as it expands, it
cools the surrounding air. The cooling often will cause ice to form around the
"horn" where the gas is expelled from the extinguisher. Since the fire could reignite, continue to apply the agent even after the fire appears to be out.
How to Use an Extinguisher
Even though extinguishers come in a number of shapes and sizes, they all
operate in a similar manner. You must know how to use an extinguisher before
you need it. Remember this: an easy acronym for correctly using a fire
extinguisher is PASS.
P A S
S -- Pull, Aim, Squeeze, and Sweep
Pull the pin at the top of the extinguisher that keeps the handle from being
accidentally pressed. This will allow you to discharge the extinguisher.
Aim the nozzle toward the base of the fire. If you discharge the extinguishing
agent into the flames it will fly right through it
Squeeze the handle to discharge the extinguisher while standing
approximately 8 feet away from the fire. If you release the handle, the
discharge will stop.
Sweep the nozzle back and forth at the base of the fire. After the fire appears
to be out, watch it carefully since it may re-ignite!
Topic Summary
Please take a moment to review these key points before you continue with the
next topic.
• There are two systems to classify types of fire extinguishers.
• There are four types of fire extinguishers based on the types of fires that
they can put out. They are Class A, Class B, Class C, and Class D.
• There are another four types of fire extinguishers based on the
mechanism used to put out fires. They are dry chemical extinguishers,
halon extinguishers, water extinguishers (APW), and carbon dioxide
extinguishers.
• The correct way to use fire extinguishers is PASS. That is, pull, aim,
squeeze, and sweep.
Topic 6: FPP and EAP
Developing and implementing a fire protection program should be a part of the
employer's safety and health program. It will help employees be prepared for
fire emergencies.
The fire protection program should include fire prevention plans, fire
evacuation plans, and emergency action plans. This topic addresses these
three plans.
Effective Fire Prevention
Effective fire prevention requires vigilance, action, and cooperation. Click the
circles for explanations.
• Vigilance involves regular inspection of the workplace to identify fire
hazards.
• Action is necessary to correct hazardous situations by:
o Cleaning up debris and installing effective storage and ventilation
systems for hazardous materials
o Establishing and enforcing work rules and maintenance policies
that prevent hazardous situations from arising
o Shielding or ventilating heat sources
o Repairing or replacing faulty equipment or electrical systems
• Cooperation between employers and employees is necessary to ensure
understanding of your common interests in fire prevention and to ensure
maximum effort by all concerned to notice and correct fire hazards.
Complete Fire Protection Programs
A complete fire protection program should include fire prevention plans, fire
evacuation plans, and emergency action plans.
• A fire prevention plan specifies how to be proactive in preventing fires.
• A fire evacuation plan specifies how to act in the event of leaving a fire
site.
• An emergency action plan specifies how to react to the fire (emergency
response, fight or flee, management, etc.).
Question 1: What are the serious most frequently cited fire hazard violations in
descending order?
1. Transporting or handling flammable liquids in non-approved
containers [1926.152(a)(1)].
2. Failure to have a class 2-A rated fire extinguisher within a 100 feet
(30.4 meters) of an area where class A fire hazards exist within a
building [1926.150(c)(1)(I)]. Another frequent violation related to
this one is not having at least one class 2-A rated fire extinguisher
on each floor of a multistory building located near the stairway
[1926.150(c)(1)(iv)].
3. Failure of the employer to develop and implement a fire protection
program for all phases of work involving employees on the job site
[1926.150(a)(1)].
4. Failure to inspect and maintain portable fire extinguishers to keep
them in serviceable condition [1926.150(c)(1)(iii)].
5. Lack of posting of "no smoking" signs where refueling operations
are conducted [1926.152(g)(9)], and where operations constitute
a fire hazard, which commonly will include flammable liquids and
flammable gases [1926.151(a)(3)].
Questions 2: What are some effective control measures that can be used for
the serious hazards discussed in question 1?
• The importance of developing and implementing a fire protection
program, which will be a part of the employer's safety and health
program, will help to avoid being unprepared for fire emergencies.
This is most important to those contractors that work with easily
ignitable materials such as flammable liquids and gases and those
that use equipment that depend on liquid or gaseous fuels.
Material safety data sheets (MSDS) from your supplier can be used
to determine what materials are flammable, and which ones are
•
•
•
only combustible or will not burn. Also, the MSDS will tell you
which fire extinguishing agent is effective on the specific material
if it were to catch on fire.
As part of the program, preplanning for trash and rubbish removal
is an important part of preventing fire hazards. Removing
accumulations of class A waste materials such as paper,
cardboard, wood pallets and packing materials and trash from the
work area will help minimize unwanted fires. Also, minimize the
spilling of flammable liquids by using approved safety cans or the
DOT shipping containers. Approved containers will have a
laboratory listing or label recognized by OSHA.
Where fire hazards cannot be removed from the work area, the
types of fire extinguishing equipment to be used must match the
type of materials being used and the job activities. For class A
hazards, OSHA would accept any approved 2-A rated fire
extinguisher; a 55-gallon (208 l) open drum of water with 2 fire
pails; 100 feet (30.4 m) of 1/2 (1.27cm) inch rubber or plastic
garden type hose that can supply at least 5 gallons per minute
(0.31 l/s) with a hose stream range of 30 feet (9.1 m)
horizontally; or 100 feet (30.4 m) of an approved fire hose system
that will deliver 25 gallons or more per minute (1.57 l/s).
Control of ignition sources is also an important component of the
program. Bonding and grounding metal containers when
transferring flammable liquids; posting "no smoking" signs near
fire hazards areas; and using approved lighting for hazardous
locations, such as in a confined space where flammable materials
are being used, are some examples of good control of ignition
sources.
Fire Prevention Plan (FPP)
Employers need to implement a written fire prevention plan (FPP) to
complement the fire evacuation plan in order to minimize the frequency of
evacuation. Stopping unwanted fires from occurring is the most efficient way
to handle them. The written plan should be available for employee review.
The following are some essential components in a fire prevention plan:
• Housekeeping procedures for storage and cleanup of flammable
materials and flammable waste must be included in the plan.
•
•
•
Procedures for controlling workplace ignition sources such as smoking,
welding, and burning must be addressed in the plan.
All employees are to be informed of the potential fire hazards of their job
and the procedures called for in the employer's fire prevention plan.
Review the policy to ensure that the plan will be reviewed with all new
employees when they begin their job and with all employees when the
plan is changed.
Fire Evacuation Plan (FEP)
Despite the best efforts of fire prevention, fires do occur. For this reason it is
important to develop a workplace fire safety plan that includes provisions for
fire suppression or extinguishing and emergency evacuation of workers.
A fire evacuation plan (FEP) must be in place and should contain the following
components:
• Evacuation routes (passageways, stairwells, and exit doors to the
outside) - Clearly marked, safe, and accessible exit routes are essential
to ensure that workers and other occupants can escape quickly in the
event of fire.
• Alarm systems, fire detection systems, and communication systems Alarm systems to signal the need for evacuation are essential. Fire
detection systems and communication systems to summon firefighters
are useful means of reducing the harm to people and property in the
event of fire.
• Training - All employees must be familiar with the plan, and the plan
must be reviewed prior to and during each job.
Emergency Action Plans (EAPs)
Emergency action plans (EAPs) must describe the routes that are to be used
and procedures to be followed by employees in the event of an emergency.
The following are the requirements of an emergency action plan:
• Procedures for accounting for all evacuated employees must be part of
the plan.
• The written plan must be available for employee review.
• Where needed, special procedures for helping physically impaired
employees must be addressed in the plan.
•
•
•
•
•
The plan must include procedures for those employees who must remain
behind temporarily to shut down critical plant equipment before they
evacuate.
The preferred means of alerting employees to a fire emergency must be
part of the plan.
An employee alarm system must be available throughout the workplace
complex and must be used to alert employees in an emergency
evacuation. The alarm system may be voice communication or sound
signals such as bells, whistles, or horns. Employees must know the
evacuation signal.
Employees must be trained in what is to be done in an emergency.
Employers must review the plan with newly assigned employees so they
know the correct actions to take in an emergency and with all employees
when the plan is changed.
Employers' Firefighting Policies
A critical decision for every employer is whether or not to involve employees in
firefighting efforts. Firefighting is an inherently dangerous activity and should
be undertaken only by properly trained and equipped persons. Protection of
life is the paramount consideration. In most circumstances immediate
evacuation may be the best policy, especially if professional firefighting
services are available to respond quickly.
There may be situations in which employee firefighting is warranted as a
means of affording other workers time to escape or to prevent danger to
others.
Different policies exist in the real world:
• Some employers choose a policy of evacuation and do not allow
employees to fight fires.
• Some employers allow any employee to fight incipient fires with
available portable fire extinguishers or hose/standpipe systems.
• Some employers designate only certain employees to fight fires and
direct that all others evacuate.
• Each of these employer policy options carries with it specific
requirements for compliance with OSHA fire safety standards.
Does OSHA require employers to assign firefighting duties to an employee?
OSHA does not require any employer to assign firefighting duties to an
employee. The employer always has the option to adopt a policy requiring
complete and immediate evacuation in the event of fire. In that case, the
policy must be implemented by adopting a comprehensive emergency action
plan and a fire prevention plan that meet OSHA criteria.
In situations where the employer provides fire extinguishers for general
employee use, OSHA standards specify requirements for their distribution,
placement, design, testing, and maintenance and for employee training in
their use.
Fight or Flee: The Critical Decision
A critical decision for every employee when in a fire situation is whether or not
to fight the fire. The general rule is that employees should attempt to
extinguish only small fires at the beginning stages.
Do you know when you shouldn't fight a fire?
• Do not fight a fire if you do not know what is burning.
• Do not fight a fire if is spreading rapidly.
• Do not fight the fire if you do not have adequate or appropriate
equipment.
• Do not fight a fire if the fire is producing large amounts of smoke (toxic
gases, fumes, and vapors can be fatal in very small amounts).
• Do not fight a fire if you are uncomfortable or your instincts tell you to
get out.
• Do not fight a fire if it cannot be immediately extinguished.
• Do not take chances. Always leave yourself an out.
Topic Summary
Please take a moment to review these key points before you continue with the
next topic.
• Effective fire prevention requires vigilance (regular inspections of the
workplace), action (correction of hazardous situations), and cooperation
(shared common interests between employers and employees).
• A fire prevention plan should be in place to complement the fire
evacuation plan in order to stop unwanted fires from occurring and to
minimize the frequency of evacuation.
•
•
Emergency action plans describe the routes to be used and procedures
to be followed by employees in the event of an emergency.
Firefighting is an inherently dangerous activity and should be undertaken
only by properly trained and equipped persons. In most circumstances
immediate evacuation is the best policy. Employees should attempt to
extinguish only small fires at the beginning stages.
Lesson Summary
This lesson contains information and instruction about fire protection and
prevention. By completing this lesson, you should have the knowledge to
discuss the following topics. Take a moment to see if you can do the following:
• Explain the essential elements of fires and list four types of fuel sources
• Identify seven common hazards associated with fire
• Describe the proper control mechanisms associated with using and
handling the following: electrical equipment, welding, fueling and
refueling, storage, heating device, and LPG
• Describe the proper handling of flammable or combustible liquids
including the storage requirements, the transferring requirements, and
the requirements of use
• Discuss four different types of fire extinguishers for different types of
fires and their ratings
• Discuss four different types of fire extinguishers based on the fireextinguishing agents used
• Describe the step-by-step process of using fire extinguishers
• Differentiate between an FPP and an EAP
• List situations when you shouldn't fight the fire
Signs, Signals and Barricades
Introduction
An unidentified hazard can lead to personal injury, property damage, or even
death.
Signs are recognized as one of the first attempts made to protect workers and
prevent accidents. It is impossible to know how many lives have been saved
or injuries prevented through the use of signs, signals, and barricades. Today
signs are used in the workplace to inform workers of hazards, provide
information, and instruct them in the proper way to perform their jobs. OSHA
and ANSI enforce safety specifications for your protection!
Lesson Overview
This lesson introduces OSHA's (Occupational Safety and Health Administration)
standards for signage. You will learn about the types and use of safety signs
as well as other standard requirements. Upon completing this lesson, you will
be able to:
• Summarize the need for accident prevention communication tools to
protect employees
• Explain the safety color-coding system required by OSHA and ANSI
• Distinguish among the different safety signs required by OSHA
• Describe the proper use of accident prevention signs, tags, symbols, and
barricades
Why Learn This Lesson?
This lesson will assist the learner with the proper use and placement of
accident prevention signs, tags, signals, and barricades. This lesson also will
stress the importance of having a workforce that has been trained on the
proper use of accident prevention tools and what they mean.
As part of a comprehensive safety and health program, good safety
communication tools could be the difference between life and death.
Topic Overview
This topic addresses educating the workplace about accident protection. Upon
completing this topic, you will be able to:
• Express the need for accident prevention tools
• Explain the purpose of OSHA's comprehensive communication program
• Recognize that ANSI creates voluntary standards
Topic 1: Accident Prevention Tools
The construction industry's increasingly diverse workforce has made
communicating information a more difficult task. However, the proper use of
accident prevention signs, tags, signals, and barricades can accomplish this
task successfully while protecting the employees as well as the public.
Accident prevention communication tools help protect employees. These tools
alert employees of hazards or isolate employees and the public from the
hazards associated with construction work.
Accident prevention signs, tags, signals, and barricades are used to:
•
•
•
Alert workers that personal protective equipment is required
Identify areas that are off-limits
Identify specific hazards that may be present
It is crucial that employers educate the workforce on the proper use and
placement of signs, tags, signals, and barricades.
OSHA's Communication Program
Hazards exist in every workplace, and employees need to be warned about
them. One of the easiest ways to accomplish this is with a comprehensive
communication program that includes:
• Accident prevention signs
•
•
•
Signaling systems
Barricades
Accident prevention tags
OSHA has specifications for accident prevention signs and tags in 29 CFR
1926.200. These specifications apply to the design, application, and use of
signs or symbols to prevent accidental injuries or property damage. The OSHA
specifications do not cover bulletin boards, safety posters, or street signs.
The American National Standards Institute (ANSI) is a private organization
which creates voluntary standards through consensus. Many OSHA standards
reference ANSI as the minimum requirements to follow for compliance.
Accident prevention signs and tags are cited in Z35.1, Z35.4, Z535.1, Z535.1.
Which requirements should be followed, those of OSHA or ANSI?
Where OSHA has specific requirements, they must be followed. In the
absence of OSHA requirements, employers should refer to ANSI
standards with respect to information not specifically prescribed by
OSHA.
ANSI Z35.1, Specifications for Accident Prevention Signs, and ANSI
Z35.2, Specifications for Accident Prevention Tags, contain rules that are
in addition to the rules prescribed by OSHA.
Any applicable federal, state, or municipal regulations also must be
followed.
Topic Summary
Please take a moment to review these key points before continuing with the
next topic.
• It is crucial that employers educate the workforce on the proper use and
placement of signs, tags, signals, and barricades.
• OSHA and ANSI have standard requirements for fall protection.
Topic 2: Safety and Colors
This topic demonstrates OSHA's signage color-coding system for worker
protection. Upon completing this topic, you will be able to:
• Identify OSHA's color safety designations
• List examples of color safety usage
Safety Color Identification
Colors have long been used to inform us of hazards -- at home, on the road,
and especially on the job site. OSHA and ANSI recognize that the consistent
use of colors for accident prevention signs can lead to greater protection for
workers.
Let's look at the color-coding system required by the OSHA and ANSI
standards.
RED: Safety Red identifies Danger and the command to Stop and is the color
used to mark:
• Fire protection equipment
• Safety cans or other portable containers of flammable liquids, excluding
shipping containers
• Emergency stop bars, hazardous machines, stop buttons, and other
electrical switches used for emergency stopping
YELLOW: Safety Yellow is the basic color for designating caution and for
marking physical hazards, such as striking against, stumbling, falling, and
getting caught in between objects. Solid yellow, yellow and black stripes, or
yellow and black checkers must be used for maximum contrast with the
particular background.
ORANGE: Safety Orange identifies dangerous parts of machines or energized
equipment.
GREEN: Safety Green designates safety, emergency egress, and the location
of first aid and safety equipment.
BLUE: Safety Blue identifies safety information used on informational signs
and bulletin boards.
COMBINATIONS: Safety Black, Safety White, Safety Yellow, or combinations of
Safety Black with Safety White or Safety Yellow are used to designate traffic or
housekeeping markings.
Topic Summary
OSHA and ANSI recognize that consistent color signage protects workers from
potential accidents. Please take a moment to review this color-coding system
before you continue with the next topic.
OSHA Color-Coding System:
• (Yellow) Caution
• (Orange) Dangerous Parts
• (Red) Danger
• (Green) Emergency Egress
• (Blue) Informational
• (Combo) Housekeeping/Traffic
Topic 3: Types of Signs
This topic explains the different types of safety signs required by OSHA. You
will be able to recognize the color-coding system as it applies to the sign
types. Upon completing this topic, you will be able to:
• Recognize the different types of OSHA signs
• Describe sign classifications
Danger Signs. These signs indicate that immediate danger is present and
special precautions are necessary. Danger signs are limited to the most
extreme situations. OSHA also specifies that the red, black, and white colors
used for Danger signs be in accordance with ANSI standards (Z53.1).
Caution Signs. These signs warn against potential hazards or caution the
workers against using unsafe practices. OSHA specifies that yellow and black
are the standard colors for Caution signs. The use of the colors must be in
accordance with ANSI standards (Z53.1).
Safety Instruction Signs. These signs are used where there is a need for
general instructions and suggestions relative to safe work practices, reminders
of proper safety procedures, and guides to the location of safety equipment.
OSHA specifies that the standard color for Safety Instruction signs shall be a
white background, green panel, and white letters. Any letters used on the
white background shall be black. The colors must be in accordance with ANSI
Z53.1-1979.
Warning Signs. These signs indicate a potentially hazardous situation, which if
not avoided, could result in death or serious injury.
Notice Signs. Theses signs indicate a statement of company policy as the
message relates directly or indirectly to the safety of personnel or protection
of property.
Fire Safety Signs. These signs indicate the location of emergency firefighting
equipment.
Exit Signs. These signs indicate the means of exiting the area and, when
required, must be lettered in legible red letters at least six inches high on a
white background.
Directional Signs. Directional signs, other than automotive traffic signs, should
be white with a black panel and a white directional symbol. Any additional
wording on the sign must be in black letters on the white background.
Traffic Signs. These signs are posted on construction sites at all points of
hazards. All traffic control signs or devices used for protection of construction
workers must conform to ANSI D6.1-1971, Manual on Uniform Traffic Control
Devices for Streets and Highways.
Topic Summary
Please take a moment to review these key points before continuing with the
next topic.
• Signs and symbols must be visible at all times during construction work.
• OSHA and ANSI classify safety signs according to use.
• Safety sign classifications include: Danger, Caution, Safety Instruction,
Warning, Notice, Fire Safety, Exit, Directional, and Traffic.
Topic 4: Proper Use of Signs
You now understand sign color and type. This topic teaches OSHA's general
requirements for sign design. Upon completing this topic, you will be able to:
• Summarize the general requirements for sign design
• State the minimum requirements for sign size
• Explain the rules for sign placement
General Requirements
When it comes to the use of signs, OSHA is not specific as to the design of the
sign, only its colors and its purpose. For instance, you could not have a
Danger sign in purple and orange.
Compliance
Whenever you are using signs on the construction job site, it is important to
check under the specific sign requirement to be sure you are complying with
the OSHA regulations.
Design
While design is not specified by OSHA, the Agency does require that signs
have rounded or blunt corners and that they are free from sharp edges, burrs,
splinters, or other sharp projections. This is to prevent the accident prevention
signs from becoming hazards themselves.
Materials
OSHA does not dictate the materials that are used to make the signs.
Manufacturers make signs from a variety of materials including plastic,
fiberglass, and aluminum. The user should keep in mind the environment the
signs in which the signs will be used. Will they be exposed to extreme heat,
sun, moisture, or cold? If so, then the proper materials should be used to
ensure that the signs are durable under such conditions.
Size
OSHA does not have size specifications for signs and refers to the ANSI
standard regarding these technicalities. The size of the sign, height and width
of the letters, and viewing distances are all defined by ANSI Z535.2-1998. Key
requirements include:
• The wording on any sign should be concise and easy to read.
• The size of the lettering must be as large as possible for the intended
viewing distance.
• The minimum letter height for the signal word (Danger, Caution, Notice,
etc.) is one unit of height for every 150 units of safe viewing distance.
• The minimum letter height for other words on the sign is one unit of
height for every 300 units of safe viewing distance. Click this ANSI No.
(ANSI Z535.2) to preview a list of specific measurements.
Placement
ANSI also has developed rules for the placement of signs. Signs must be
placed/equipped:
• To alert and inform employees of hazards in sufficient time to avoid the
hazard and take appropriate action. Employees should not be in harm's
way before seeing the sign.
• For legible, do not create a distraction, and are not hazards in
themselves.
• Not be placed on moveable objects or adjacent to moveable objects like
doors, windows etc., which if moved will obscure the sign.
• With emergency (battery operated) illumination or be reflective or both
when illumination may be necessary under emergency conditions.
Topic Summary
Please take a moment to review these key points before you continue with the
next topic. When it comes to the proper use of signs, OSHA's considerations
are to:
• Plan with sign's color and purpose in mind, not its design
• Manufacture to ensure that they are durable under environmental
conditions
• Specify for concise and easy-to-read wording
• Place, adjust, and illuminate in sufficient time to alert
Topic 5: Other Communications
This topic addresses other important warning communications: signaling,
barricades, and prevention tags. Upon completing this topic, you will be able
to:
• Identify how and when to use signals
• Explain the use of barricades
• Determine when to use accident prevention tags
Signaling
Understanding how and when to use signals that communicate important
directions for the movement of equipment and personnel on the job site is
critical.
Flagmen
When operations exist where the use of signs, signals, and barricades do not
provide the necessary protection on or adjacent to a highway or street,
flagmen or other appropriate traffic controls have to be provided. Flagman
observe these guidelines:
• Conform signaling directions to the American National Standards
Institute ANSI D6.1, Manual on Uniform Traffic Control Devices for
Streets and Highways.
• Perform hand signaling with red flags that are at least 18 inches square
or use sign paddles. They must use red lights when it is dark.
• Wear a red or orange warning garment while flagging. Any warning
garments that are to be worn at night must be made of reflective
material.
Barricades
Barricades and barricade tape offer good visual awareness and provide
physical obstacle to hazards. Barricades that are used for the protection of
employees must conform to ANSI standards. See ANSI D6.1, Manual on
Uniform Traffic Control Devices for Streets and Highways.
Accident Prevention Tags
Accident prevention tags are used as a temporary means of warning
employees of an existing hazard, such as defective tools, equipment, etc. They
should not be used in place of, or as a substitute for, accident prevention
signs.
Topic Summary
Please take a moment to review these key points before you continue with the
next topic.
• Flagman signal directions must conform to the ANSI codes, and flagmen
are required to use red flags, red lights, and red garments.
• Barricades provide visual and physical hazard protection.
• Accident prevention tags are temporary warning tools for existing
hazards.
Lesson Summary
This lesson contains information and instruction about recognition and proper
use of signage. By completing this lesson, you should have the knowledge to
discuss the following topics. Take a moment to see if you can do the following:
• Determine when to refer to OSHA and ANSI standards for signage
specifications
• Summarize the need for accident prevention communication tools to
protect employees
• Explain the safety color-coding system required by OSHA and ANSI
• Distinguish among the different safety signs required by OSHA
• Describe the proper use of accident prevention signs, tags, symbols, and
barricades
Material Handling
Introduction
Handling and storing materials involves diverse operations, such as hoisting
tons of steel with a crane. Other operations include:
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Driving a truck loaded with concrete blocks
Carrying bags and materials manually
Stacking drums, barrels, kegs, lumber, or loose bricks
The efficient handling and storing of materials is vital to industry. These
operations make possible a continuous flow of raw materials, parts, and
assembly throughout the workplace and ensure that materials are available
when and where they are needed. The improper handling and storing of
materials can lead to costly injuries.
Lesson Overview
In this lesson you will learn about the proper handling, storage, and use of
materials. You also will learn why it is important to take the time to organize
the job site and use the right equipment for the job.
Upon completing this lesson, you will be able to:
• Describe the control methods for preventing hazards while handling
materials
• Move and store different materials on construction sites safely
• Use material handling equipment properly, safely, and efficiently
Why Learn This Lesson?
Since the dawn of civilization societies have survived or perished by how
efficiently they organized their stores of food, weapons, water, and other
essentials for survival.
It may not be that dramatic in today's construction industry, but a wellorganized job starts with the proper handling, storage, and use of materials.
The proper handling, storage, and use of materials can not only save a
company time and money, it can also reduce waste and the potential for
damaged equipment or injured employees.
This lesson gives you an opportunity to better understand the importance of
proper material handling and storage. In addition, you will learn why it is
important to take the time to organize the job site, use the right equipment
for the job, and better use materials as the job progresses.
Topic 1: Control Methods
This topic introduces safety methods for preventing hazards when handling
materials. Upon completing this topic, you will be able to:
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Identify the hazards associated with handling materials
Recognize the need for efficient housekeeping
Define the hierarchy of controls
Describe OSHA's requirements for disposal, manufacturers, and training
requirements when handling materials
Hazards
Unfortunately, in the process of handling, storing, using, and/or disposing of
materials, workers can be injured by falling objects, improperly stacked
materials, or by various types of equipment.
When manually moving materials, workers should be aware of potential
injuries, including the following:
• Strains and sprains from improperly lifting loads, or from carrying loads
that are either too large or too heavy
• Fractures caused by being struck by materials, or by being caught in
pinch points
• Cuts and contusions caused by falling materials that have been
improperly stored, or by incorrectly cutting ties or other securing devices
It is important to be aware of incidents that might result from improper
handling and storing of materials and improper work practices, and to
recognize the methods for eliminating, or at least minimizing, such incidents.
Consequently, employers and employees can and should examine their
workplaces for any unsafe or unhealthful conditions, practices, or equipment
and take the necessary steps to correct them.
Methods
Some very basic safety principles can help reduce workplace violations and
incidents. These include:
• Work practices
• Training
• Education
Whether moving materials manually or mechanically, employees should be
aware of the potential hazards associated with the task at hand and know how
to exercise control over their workplaces to minimize the danger.
Housekeeping
OSHA's standards have a common theme concerning housekeeping, and it is
very simple:
A tidy job site is a more efficient and safer job site.
This is not simply a comment but a statement of fact. This lesson focuses on
materials handling, storage, use, and disposal; all of these items are closely
related to housekeeping. As you will see in this lesson, there are prescribed
methods for moving, storing, using, and disposing of materials.
Storage areas must be kept free from accumulation of materials that
constitute hazards from tripping, fire, explosion, or pest harborage. In
addition, vegetation control should be exercised when necessary.
Hierarchy of Controls
Reducing the risks associated with construction work is very important. To
meet this goal, there is a hierarchy or preferred order of control. These
controls are not mutually exclusive. There may be occasions when more than
one control must be used to reduce a risk. However, prevention would be best
served by implementing your hierarchy or control methodology before you
start any construction operation. The preferred order is presented in the
graphic.
By using controls, including protective equipment and proper work practices,
you can work with confidence.
Administrative and engineering controls can be used to eliminate material
handling hazards before beginning operations. Personal protective equipment
(PPE) as a protection device is your last line of defense and protects you from
material handling hazards.
OSHA Requirements
OSHA is dedicated to providing a safe workplace for handling materials. Click
each graphic to learn about OSHA's recommendations for the specific area.
Disposal
• Whenever materials are dropped more than 20 feet to any point lying
outside the exterior walls of the building, an enclosed chute of wood or
equivalent material must be used. For the purposes of this lesson, an
enclosed chute is a slide, closed in on all sides, through which material is
moved from a high place to a lower one.
• When debris is dropped through holes in the floor without the use of
chutes, the area onto which the material is dropped must be completely
enclosed with barricades not less than 42 inches high and not less than
6 feet back from the projected edge of the opening above.
• Signs warning of the hazard of falling materials must be posted at each
level.
• Removal must not be permitted in this lower area until debris handling
ceases above.
• All scrap lumber, waste material, and rubbish must be removed from the
immediate work area as the work progresses.
• Disposal of waste material or debris by burning must comply with local
fire regulations.
• All solvent waste, oily rags, and flammable liquids must be kept in fireresistant, covered containers until removed from the worksite.
Manufacturers
This lesson stresses the importance of working with your equipment
manufacturers. Your manufacturer can provide you with not only the proper
equipment but also the proper training on the specific equipment.
Other applications not addressed in this lesson must always be referred to an
expert.
Training
OSHA requires that an employer instruct each employee in the recognition and
avoidance of unsafe conditions and the standards applicable to his or her work
environment to control or eliminate any hazards or other exposure to illness or
injury.
Topic Summary
Please take a moment to review these major points before you continue with
the next topic.
• The risks associated with material handling include potential injuries to
personnel and damage to equipment or property.
• Good housekeeping on a job site promotes efficiency and safety.
• The preferred order of control is (1) engineering, (2) administrative, and
(3) personal protective equipment.
• OSHA has specific material handling requirements for disposal,
manufacturers, and training. -
Topic 2: Material Handling
This topic addresses the different materials that are common to construction
sites, particularly their moving and storage. Upon completing this topic, you
will be able to:
• Identify the safety precautions for moving materials
• Implement the general guidelines for storing materials
Moving Materials
Manually
When manually moving materials, employees must:
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Seek help when a load is so bulky it cannot be properly grasped or lifted,
when they cannot see around or over it, or when a load cannot be
handled safely
Make sure handles and holders are attached to loads to reduce the
chances of getting fingers pinched or smashed
Use appropriate personal protective equipment to protect themselves
from heavy or bulky loads or loads with sharp edges
When an employee is placing blocks under raised loads, he or she must:
Not release the load until the hands are clearly removed from the load
Use large and strong blocking materials and timbers to support the load
safely
Not use materials with evidence of cracks, rounded corners, splintered
pieces, or dry rot
Mechanically
When mechanically moving materials with forklifts, cranes, etc., workers must
follow these guidelines:
• The equipment must not be overloaded; the weight, size, and shape of
the material being moved must dictate the type of equipment used to
transport it.
• All materials handling equipment has rated capacities that specify the
maximum weight the equipment can safely handle and the conditions
under which it can handle those weights.
• The equipment capacity ratings must be displayed on each piece of
equipment and must not be exceeded except for load testing.
• When picking up items with a powered industrial truck:
• The load must be centered on the forks and as close to the mast as
possible to minimize the potential for the truck tipping or the load
falling.
• A lift truck must never be overloaded because it would be hard to control
and could easily tip over.
• Extra weight must not be placed on the rear of a counterbalanced forklift
to offset an overload.
• The load must be at the lowest position for traveling, and the truck
manufacturer's operational requirements must be followed.
• All stacked loads must be correctly piled and cross-tiered, where
possible. Precautions also should be taken when stacking and storing
material.
Dockboards (Bridge Plates)
When using dockboards, workers must follow these policies:
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Portable and powered dockboards must be strong enough to carry the
load imposed on them.
Portable dockboards must be secured in position, either by being
anchored or equipped with devices to prevent their slipping. Handholds,
or other effective means, must be provided on portable dockboards to
permit safe handling.
Positive protection must be provided to prevent railroad cars from being
moved while dockboards or bridge plates are in position.
General Storage
Accumulated materials: Storage areas must be kept free of accumulated
materials that may cause tripping, fires, or explosions, or that may contribute
to the harboring of rats and other pests.
Stacked and piled materials: When stacking and piling materials, it is
important to be aware of such factors as the materials' height and weight, how
accessible the stored materials are to the user, and the condition of the
containers in which the materials are being stored. Material that cannot be
stacked due to size, shape, or fragility can be safety stored on shelves or in
bins. For quick reference, walls or posts may be painted with stripes to
indicate maximum stacking heights.
Bound materials: All bound materials should be stacked, placed on racks,
blocked, interlocked, or otherwise secured to prevent them from sliding,
falling, or collapsing. A load greater than that approved by a building official
may not be placed on any floor of a building or other structure. Where
applicable, load limits approved by the building inspector should be posted
conspicuously in all storage areas.
Materials stored in tiers: All materials stored in tiers must be stacked, racked,
blocked, interlocked, or otherwise secured to prevent sliding, falling, or
collapse. Maximum safe load limits of floors within buildings and structures, in
pounds per square foot, must be posted conspicuously in all storage areas,
except for floor or slab on grade. Maximum safe loads must not be exceeded.
Aisles and passageways: Aisles and passageways must be kept clear to
provide for the free and safe movement of material handling equipment or
employees. Such areas must be kept in good repair. When a difference in
road or working levels exists, means such as ramps, blocking, or grading must
be used to ensure the safe movement of vehicles between the two levels.
Materials in buildings under construction: Materials stored inside buildings
under construction must not be placed within 6 feet of any hoistway or inside
floor openings, or within 10 feet of an exterior wall that does not extend above
the top of the material being stored.
Working on stored materials: Each employee required to work on stored
material in silos, hoppers, tanks, and similar storage areas must be equipped
with personal fall arrest equipment meeting OSHA's fall protection
requirements.
Incompatible materials: Incompatible materials must be segregated in
storage.
Material Storage
A number of specific materials pose unique hazards. Click each drawer to learn
about its storage precautions.
Lumber
Lumber must be stacked on level and solidly supported sills and must be so
stacked as to be stable and self-supporting. The piles must not exceed 20 feet
high, and lumber to be handled manually must not be stacked more than 16
feet high. All nails must be withdrawn from used lumber before stacking.
Pipes and bars
Pipes and bars should not be stored in racks that face main aisles; this could
create a hazard to passers-by when supplies are being removed.
Cylindrical materials
Structural steel, poles, pipe, bar stock, and other cylindrical materials, unless
racked, must be stacked and blocked so as to prevent spreading or tilting.
Bagged materials
Bagged materials must be stacked by stepping back the layers and crosskeying the bags at least every 10 bags high.
Bricks
Brick stacks must not be more than 7 feet high. When a loose brick stack
reaches a height of 4 feet, it shall be tapered back 2 inches in every foot of
height above the 4-foot level.
Blocks
When masonry blocks are stacked higher than 6 feet, the stack must be
tapered back one-half block per tier above the 6-foot level.
Drums, barrels, and kegs
Drums, barrels, and kegs must be stacked symmetrically. If stored on their
sides, the bottom tiers must be blocked to keep them from rolling. When
stacked on end, put planks, sheets of plywood dunnage, or pallets between
each tier to make a firm, flat, stacking surface. When stacking materials two
or more tiers high, the bottom tier must be chocked on each side to prevent
shifting in either direction.
Topic Summary
Please take a few minutes to review these key points before you continue with
the next topic.
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Workers must follow specific guidelines for moving materials manually,
mechanically, and with dockboards.
There are important general safety precautions for storing materials.
A number of materials have unique storage requirements.
Topic 3: Material Handling Equipment
This topic explores the different equipment used in moving heavy loads on a
worksite. Choosing the best method of rigging and hoisting seriously affects
your safety. You will examine the different types of slings and their specific
applications.
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Identify safe measures for rigging and hoisting
Recognize the different types of slings
Determine how to select and inspect slings
Identify the specific requirement for slings: alloy steel chains, wire rope,
natural rope, and synthetic webbing
Rigging
To reduce the potential for incidents associated with workplace equipment,
employees need to know the proper uses and limitations of the equipment
they are operating when handling material. This includes how to effectively
use equipment such as forklifts, cranes, and slings. This section covers
rigging, hoisting and slings, but it will not cover cranes and forklifts. Those
topics will be coved in a separate lesson.
When moving and storing construction materials, workers engage in rigging.
Rigging is the act of attaching hoisting equipment to the load. Slings and
hoists are tools used in many industries for moving large, heavy loads. Slings
and hoists are available in hundreds, if not thousands, of styles. This
tremendous selection can make the job of choosing the correct sling or hoist
very challenging. The wrong choice has led to thousands of incidents and even
death each year in the United States.
Hoisting
A hoist is a manual or power-operated lifting device for raising and lowering
loads. Its service area is vertical over its mounting. Hoists may be attached to
fixed or moveable structures by an upper hook or bracket and are used in
combination with other equipment, e.g., trolleys and boom cranes. The types
of hoists are listed below.
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Direct-geared
Drum
Friction drum
Lever-operated
Come-along
Hoist Selection
The best way to select the proper hoist is to consider the working conditions
the hoist will be subjected to and the type of application it will be required to
perform. Before selecting a hoist, carefully consider these factors:
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Selection Considerations
Duty cycle
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Distance
Lift
Efficiency
Headroom
Safety
Atmosphere
Economy
Speeds
The primary concern for selection will be the capacity required for the load to
be lifted. Not only must you consider the largest load you intend to handle,
you must include the weight of any hook-lifting devices such as spreader bars,
grabs, slings, etc.
You can find OSHA's recommended safe working loads (Tables H-1 through H20) under Regulations (Standards -29 CFR). Rigging equipment for material
handling- 1926.251. Subpart H, Subpart: Materials Handling, Storage, Use,
and Disposal. Please view an example of the working load limits table by
scrolling down to alloy steel chains, Table H-1 (under section (f) (2) ) of the
standard.
Hoist Inspection
It is important to check this ancillary equipment as well as the hoist. An
engineer should verify that both devices will tolerate the stress applied to
them. Despite the fact that most hoists do have a safety factor allowance,
never exceed the rated capacity stamped on the hoist for any reason.
Exceeding the rated capacity, even for a short period, will cause equipment
damage and can result in serious injury.
Here are specific rigging applications:
• Rigging equipment for material handling must be inspected prior to use
on each shift and as necessary during its use to ensure that it is safe.
• Defective rigging equipment must be removed from service.
• Rigging equipment must not be loaded in excess of its recommended
safe working load.
• Rigging equipment, when not in use, must be removed from the
immediate work area so as not to present a hazard to employees.
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Special custom-design grabs, hooks, clamps, or other lifting accessories
for such units as modular panels and prefabricated structures must be
marked to indicate the safe working loads and be proof-tested to 125
percent of their rated load prior to use.
Slings
Slings are used in combination with a lifting device. The most common lifting
devices are overhead cranes, hoists, and forklifts. When working with slings,
you must visually inspect them before each use and during operation,
especially if they are being used under heavy stress. Also observe the
following safety guidelines:
• A damaged or defective sling must be removed from service.
• Slings cannot be shortened with knots or bolts or any other makeshift
devices, and sling legs that have been kinked must not be used.
• Manufacturers of slings rate their capacity, and they should not be
loaded beyond that rating.
Sling Selection
To select the correct sling, two questions must be answered: what type of
sling and what size (diameter or thickness)?
The main types of slings and their applications are:
1. Chain: Combines superior strength, ease of handling, and durability. The
combination of heavy loads, elevated working temperatures, and severe
lift conditions usually dictate that an alloy chain sling be used. It
typically is used in steel mills, foundries, and heavy machining
operations that require repetitive lifts.
2. Wire Rope: The most commonly used sling. It has the lowest cost per
ton of lift and is used in the construction industry and other industries
where heavy loads and rugged conditions exist.
3. Mesh - Wire and Chain: Excellent for lifting objects that are hot or have
sharp edges, such as bar stock or plate steel. Mesh slings usually have
wide load-bearing surfaces that greatly enhance load balancing. Machine
shops and steel warehouses typically have applications requiring mesh
slings.
Sling Inspection
Each day before use, the sling and all fasteners and attachments must be
inspected for damage or defects by a competent person designated by the
employer. Additional inspections must be performed during sling use, where
service conditions warrant. Damaged or defective slings must be removed
from service immediately.
Alloy Steel Chain
• Welded alloy steel chain slings must have permanently affixed durable
identification stating size, grade, rated capacity, and sling manufacturer.
• Hooks, rings, oblong links, pear-shaped links, welded or mechanical
coupling links, or other attachments, when used with alloy steel chains,
must have a rated capacity at least equal to that of the chain.
• Job or shop hooks and links, or makeshift fasteners formed from bolts,
rods, etc., or other such attachments, must not be used.
• Rated capacity (working load limit) for alloy steel chain slings must
conform to the values shown in the attached tables.
• Whenever wear at any point of any chain link exceeds that shown in the
attached tables, the assembly must be removed from service.
Inspections
In addition to the inspection highlighted in other parts of this lesson, a
thorough periodic inspection of alloy steel chain slings in use must be made on
a regular basis, to be determined on the basis of:
• Frequency of sling use
• Severity of service conditions
• Nature of lifts being made
• Experience gained on the service life of slings used in similar
These inspections must in no event be less often than once every 12 months.
The employer must make and maintain a record of the most recent month in
which each alloy steel chain sling was thoroughly inspected and must make
such record available for examination.
Wire Rope
Conditions
Standard tables must be used to determine the safe working loads of various
sizes and classifications of improved plow steel wire rope and wire rope slings
with various types of terminals. For sizes, classifications, and grades not
included in these tables, the safe working load recommended by the
manufacturer for specific, identifiable products must be followed, provided that
a safety factor of not less than 5 is maintained.
Safety factor means the ratio of the ultimate breaking strength of a member
or piece of material or equipment to the actual working stress or safe load
when in use.
Follow these conditions:
• Standard tables must be used.
• Protruding ends of strands in splices on slings and bridles must be
covered or blunted.
• Knots must not secure wire rope, except on haul-back lines on scrapers.
Limitations
The following limitations must apply to the use of wire rope: An eye splice
made in any wire rope must have not less than three full tucks. However, this
requirement shall not operate to preclude the use of another form of splice or
connection that can be shown to be as efficient and is not otherwise
prohibited.
• Except for eye splices in the ends of wires and for endless rope slings,
each wire rope used in hoisting or lowering, or in pulling loads, must
consist of one continuous piece without knot or splice.
• Wire rope clips or knots must not form eyes in wire rope bridles, slings,
or bull wires.
• When U-bolt wire rope clips are used to form eyes, the tables must be
used to determine the number and spacing of clips.
• Slings must not be shortened with knots or bolts or other makeshift
devices.
• Sling legs must not be kinked.
• Slings used in a basket hitch must have the loads balanced to prevent
slippage.
• Slings must be padded or protected from the sharp edges of their loads.
• Shock loading is prohibited.
Minimum Sling Lengths
• Cable laid, 6 x 19, and 6 x 37 slings must have a minimum clear length
of wire rope 10 times the component rope diameter between splices,
sleeves, or end fittings.
• Braided slings must have a minimum clear length of wire rope 40 times
the component rope diameter between the loops or end fittings.
• Cable laid grommets, strand laid grommets, and endless slings must
have a minimum circumferential length 96 times their body diameter.
• End Attachments
• Welding of end attachments, except covers to thimbles, must be
performed prior to the assembly of the sling.
• All welded end attachments must be proof-tested by the manufacturer
or equivalent entity at twice their rated capacity prior to initial use.
• The employer must retain a certificate of proof test and make it available
for examination.
Natural Rope
Conditions
Eye Splices
• For all eye splices, the eye must be sufficiently large to provide an
included angle of not greater than 60 degrees at the splice when the eye
is placed over the load or support.
• Knots must not be used in lieu of splices.
• In manila rope, eye splices must contain at least three full tucks, and
short splices must contain at least six full tucks (three on each side of
the center line of the splice).
• All splices in rope slings provided by the employer must be made in
accordance with the fiber rope manufacturer's recommendations.
• In layed synthetic fiber rope, eye splices must contain at least four full
tucks, and short splices must contain at least eight full tucks (four on
each side of the center line of the splice).
• Fiber rope slings must have a minimum clear length of rope between eye
splices equal to 10 times the rope diameter.
• Clamps not designed specifically for fiber ropes must not be used for
splicing.
Tails
• Strand end tails must not be trimmed short (flush with the surface of the
rope) immediately adjacent to the full tucks.
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For fiber ropes under 1-inch diameter, the tails must project at least six
rope diameters beyond the last full tuck.
For fiber ropes 1-inch diameter and larger, the tails must project at least
6 inches beyond the last full tuck.
In applications where the projecting tails may be objectionable, the tails
must be tapered and spliced into the body of the rope using at least two
additional tucks (which will require a tail length of approximately six
rope diameters beyond the last full tuck).
Safe Operating Temperatures
Natural and synthetic fiber rope slings, except for wet frozen slings, may be
used in a temperature range from minus 20° to plus 180°F without decreasing
the working load limit.
For operations outside this temperature range and for wet frozen slings, the
sling manufacturer's recommendations must be followed.
End Attachments
Fiber rope slings must not be used if end attachments in contact with the rope
have sharp edges or projections.
Removal From Service
Natural and synthetic fiber rope slings must be removed from service
immediately if any of the following conditions are present:
• Abnormal wear
• Powdered fiber between strands
• Broken or cut fibers
• Variations in the size or roundness of strands
• Discoloration or rotting
• Distortion of hardware in the sling
Synthetic Webbing
Slings
The employer must have each synthetic web sling marked or coded to show:
• Name or trademark of manufacturer
• Rated capacities for the type of hitch
• Type of material
• Webbing
Synthetic web slings must be removed from service immediately if any of the
following conditions are present:
• Acid or caustic burns
• Melting or charring of any part of the sling surface
• Snags, punctures, tears, or cuts
• Broken or worn stitches
• Distortion of fittings
Fittings
Fittings must meet these standards:
• Fittings must be of a minimum breaking strength equal to that of the
sling.
• They must be free of all sharp edges that could in any way damage the
webbing.
• Attachment of end fittings to webbing and formation of eyes (Ed.: We're
missing a verb. What about the end fittings?)
• Stitching must be the only method used to attach end fittings to the
webbing and to form eyes.
• The thread must be in an even pattern and contain a sufficient number
of stitches to develop the full breaking strength of the sling.
Environmental Conditions
When synthetic web slings are used, the following precautions must be taken:
• Nylon web slings must not be used where fumes, vapors, sprays, mists,
or liquids of acids or phenolics are present.
• Polyester and polypropylene web slings must not be used where fumes,
vapors, sprays, mists, or liquids of caustics are present.
• Web slings with aluminum fittings must not be used where fumes,
vapors, sprays, mists, or liquids of caustics are present.
Safe Operating Temperatures
Synthetic web slings of polyester and nylon must not be used at temperatures
in excess of 180°F. Polypropylene web slings must not be used at
temperatures in excess of 200°F.
Shackles and Hooks
Tables must be used to determine the safe working loads of various sizes of
shackles, except that higher safe working loads are permissible when
recommended by the manufacturer for specific, identifiable products, provided
that a safety factor of not less than 5 is maintained.
The manufacturer's recommendations must be followed in determining the
safe working loads of the various sizes and types of specific and identifiable
hooks.
All hooks for which no applicable manufacturer's recommendations are
available must be tested to twice the intended safe working load before their
initial use.
The employer must maintain a record of the dates and results of such tests.
Sling Size
The size of the sling is determined by the weight, shape, and size of the load.
When determining the stress that will be applied to a sling, the length of the
sling is divided by the vertical distance from the top of the load to the lifting
device. The resulting quotient is multiplied by the shared weight of the load.
Topic Summary
Please take a moment to review these key points before you continue with the
next topic.
• While rigging, workers use slings and hoists to move large heavy loads.
• When selecting a proper hoist, the primary concern is the capacity
required for the load to be lifted. OSHA provides tables to identify safe
working loads.
• Careful consideration should be given to the selection and inspection of
slings. It is important to ask: what type of sling, what size, and was it
inspected.
• There are numerous safety guidelines for the four sling types: (1) wire,
(2) synthetic, (3) chain, and (4) mesh.
• Use OSHA's tables to determine the safe load capacity for shackles and
the manufactures' recommendations for the use of hooks.
• The size of the sling is determined by the weight, shape, and size of the
load. There is a formula to determine the stress level, and the Rigger's
Reference Chart determines the diameter.
Lesson Summary
This lesson contains information and instruction about material handling. By
completing this lesson, you should have the knowledge to discuss the following
topics. Take a moment to see if you can do the following:
• Describe the control methods for preventing material hazards
• Move and store different materials on construction sites safely
• Use material handling equipment properly, safely, and efficiently
Manual Lifting
Introduction
It is estimated that 85 percent of the population will suffer from back pain at
some time during their lives. Nationally, employers will spend a staggering
$16 billion per year on time lost, benefits, and medical treatment for back
problems.
The construction industry is one of the economy's largest employers. Most
construction jobs are physically demanding, and the employee is faced with
many different variables throughout the day that may lead to back injuries.
According to the Bureau of Labor Statistics (BLS), back injuries account for
one of every five injuries and illnesses in the workplace. Of these injuries, 80
percent involve the lower back and are associated with the manual handling of
materials.
Men ages 25-34 are the people most likely to develop back injuries. Most of
these lifting injuries occur within the first second of the lift while the worker's
back is in the over position.
Lesson Overview
This lesson describes and demonstrates the proper techniques of lifting. In this
lesson you also will learn about the anatomy of the back, risk factors for back
injuries, and OSHA and NIOSH recommendations for preventing back injuries.
Upon
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completing this lesson, you will be able to:
Describe the anatomy of the back
Identify causes of back pain and five risk factors for back injuries
Demonstrate proper lifting techniques
State specific engineering and administrative controls that OSHA
suggests
Why Learn This Lesson?
Proper lifting techniques can help prevent downtime due to avoidable back
injuries. With a little practice, precautionary methods such as the ones you will
learn in this lesson can become good daily habits that could help prevent back
injuries both on and off the job.
This lesson will help you recognize and prevent back injuries that could
decrease your ability to enjoy a normal life both at work and at home.
Remember that your workday is one-third of your total day. Plan your tasks
carefully to avoid a painful back so you can enjoy your time at home with
family and friends and your favorite leisure activities. Managing your back is
your responsibility.
Topic 1: Anatomy of the Back
In order to understand why back injuries are so common, you have to
understand a little bit about the anatomy of the back and the physical forces
that come into play.
The back is composed of vertebrae, discs, nerves, and muscles.
Vertebrae: The back has 33 vertebrae, which are cylinder-shaped bones
covering the spinal cord, stacked vertically together and separated by discs to
form the spine
Discs: The discs are made up of a dense cartilage that is positioned between
the vertebrae. Each of the spinal discs is made up of a jelly-like center
surrounded by rings of tough, fibrous tissue. The discs of the spine serve as
shock absorbers during activities like sitting, standing, walking, lifting,
bending, and twisting.
Nerves: Nerves are a collection of fibers that act much like electrical wiring
which carry messages throughout the body. The spinal cord is a large nerve
that runs the length of the vertebrae. The spinal cord also has smaller nerves
that branch off the main spinal cord and send messages to other parts of the
body.
Muscles, Ligaments, and Tendons: Muscles are tissues within the body that
support the skeleton and contract to allow movement. Ligaments are bands of
tough tissue that connect the bones and cartilage together and help support
the joints. Tendons are made up of a tough, cord-like material that connects
the muscle to the bones.
The basic functions of the spine are to:
• Provide support
• Protect the spinal cord
• Allow the flexibility to move forward, bend side to side, and rotate
When the spine is aligned correctly, it forms three natural curves called the
cervical, thoracic, and lumbar curves. When these natural curves are
maintained, the spine remains healthy and in balance.
The Lower Back
The lower part of the back holds most of the body's weight. Even a minor
problem with the bones, muscles, ligaments, or tendons in this area can cause
pain when a person stands, bends, or moves around. Less often, a problem
with a disc can pinch or irritate a nerve from the spinal cord, causing pain that
runs down the leg or below the knee, called sciatica. Every time you bend or
move, these disc compress with the motion of the spine.
Eventually, discs can collapse or herniate, vertebrae can shift, and bone spurs
can develop. Tearing or straining ligaments and muscles can cause acute or
immediate injuries to the back. Muscles can also spasm due to stress or
tension.
The Forces Involved
The amount of force placed on your back under certain conditions can be
surprising. Any time you bend or lean over to pick up something, you put
tremendous pressure on your lower back.
To demonstrate this, think of your back as a lever. With the fulcrum in the
center of the lever, how many pounds would it take to lift a 10-pound object?
With the fulcrum in the center, it takes 10 pounds to lift the 10-pound object.
However, if you shift the fulcrum to one side, this will change.
If you think about it, when you bend over to pick something up, your waist
acts as the fulcrum point in the lever system, and it is certainly not centered.
With the fulcrum shifted away from the object, it takes more force to lift the
object. In fact, the human back operates on a 10:1 ratio. Bending over to lift a
10-pound object actually puts 100 pounds of pressure on your lower back.
When you add in the 105 pounds of the average human upper torso, you see
that lifting a 10-pound object actually puts 1,150 pounds of pressure on the
lower back. If you were 25 pounds overweight, it would add an additional 250
pounds of pressure on your back every time you bent over. Given these
figures, it is easy to see how repetitive lifting and bending can quickly cause
back problems.
Topic Summary
Please take a moment to review these points before you continue with the
next topic.
• The back is composed of vertebrae, discs, nerves, and muscles.
• The basic functions of the spine are to:
o Provide support
o Protect the spinal cord
o Allow the flexibility to move forward, bend side to side, and rotate
• The lower part of the back supports most of the body's weight.
• The human back operates on a 10:1 ratio of pressure on the lower back
to the weight of an object to be lifted.
Topic 2: Back Injuries
In this topic you will learn about back injuries. Upon completing this topic, you
will be able to:
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Identify causes of back pain
Describe five risk factors for back injuries and how to prevent them
Match back hazards with occupations
Causes of Back Pain
Back pain is caused by anything that puts pressure on your back muscles
and/or nerves. This can happen as a result of stress, tension, strain, injury,
illness, and poor conditioning. Injuries are often caused by physical activities
such as lifting, bending, twisting, pulling, pushing, etc.
Other factors that may increase the risk of back injury or complicate recovery
include age, weight, diet, smoking, and heredity. A back injury can be a minor
irritant or extremely painful.
Some back pain comes on slowly over time while some injuries happen
suddenly. The pain following an injury might last a short time or could last the
rest of your life. Strains and sprains are the most common forms of back
injury in construction industries. They occur when muscles are weak and
unprepared to accept the load required for many construction tasks.
The disc is the most likely site of a back injury. Discs can become injured
when too much pressure is put on them or they can degenerate with age.
Improper lifting techniques tire the back muscles. When ligaments that don't
normally stretch are stretched, they remain extended. Because of its
progressive nature, it is known as a cumulative trauma disorder, and this sets
the stage for a back injury that can require a long period of recovery. Such
injuries keep the employee away from his or her job, which affects the
company as well as the employee.
Risk Factors for Back Injuries
There are five risk factors that lead to back injuries. Click each factor to learn
about how to prevent the back injuries.
Poor Posture
Being aware of your posture throughout the day will help maintain the natural
curves of the spine. Being more aware of the spine's alignment allows for the
back to be more prepared to accept the different stresses it will face
throughout the day.
Do the following to prevent back injuries that result from poor posture:
• Always maintain good posture so your body is balanced and gives you
proper support.
• Stretch often throughout the day to keep your body flexible.
• Do not force your body to conform to its workspace.
• Raise or lower your work surface to prevent awkward positions.
• Take mini-breaks throughout the day to allow your spine to rest and
straighten.
Remember, combinations of awkward posture, force, repetition, and
insufficient rest periods are a setup for injury.
Poor Physical Condition
Your joints and ligaments need to be put through their full range of motion
regularly in order for muscles and ligaments to maintain enough elasticity to
support the spine efficiently. It is important to keep your back and your
abdominal muscles strong. The abdominal muscles help pull the pelvis into
forward rotation, which keeps the spine in a healthy curve. Weak abdominal
muscles result in a bowed or swayed back, which can increase the chance of
low back injuries.
Do the following to prevent back injuries that are due to poor physical
condition:
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By performing simple back conditioning exercises, such as partial sit-ups
and pelvic tilts (pushing the lower back to the floor), you can promote a
healthy back.
By keeping your body weight under control, you avoid putting excess
weight and pressure on the lower back.
By avoiding tobacco and alcohol and participating in some form of
exercise three times a week for 30 min each session, you can improve
the overall conditioning that protects you back.
Improper Body Mechanics
If you have to move or lift a load, you must think about your back. Remember
to lift with common sense and be aware of your body's position at all times.
Try to avoid working in awkward positions. The safe lifting zone is between the
knees and the shoulders. If the load to lift is below your knees, then bend your
knees and lift with the legs. If the load is above your shoulders you should use
a stool or a ladder. If the load is too heavy, get help.
Most back injuries occur with a lifting and twisting motion at the waist. Try to
prevent lifting and twisting by first lifting the load and straightening the back.
Then turn by stepping to the side, not pivoting at the waist. This prevents the
spine from twisting, which can make it weaker.
Remember these rules:
1. Lift with common sense!
2. Remember, no single technique will work in all circumstances.
3. Be careful!
Incorrect Lifting
Most back injuries occur while performing a simple movement. The problem is
that the movement is usually done improperly, for instance bending, lifting,
and twisting at the same time. The average back cannot handle the stresses of
these combined movements while lifting heavy or even light objects.
Don't forget, you should keep your back as vertical as possible and bend at
the knees.
Jobs That Require a High Level of Energy (Physically Demanding)
Construction workers typically have one of the most physically demanding and
dangerous jobs in all industries. Construction workers are frequently forced to
lift heavy objects. To complicate these lifts, they are required to bend, twist,
and reach while lifting. Construction work also requires lifting and carrying
awkward objects such as lengths of steel and wood and large sections of
plywood. These objects can shift while being carried, which requires a quick
recovery by the worker to prevent falling or dropping the object. These quick
recovery movements are a major cause of injury in the construction industry.
What's the correct technique for lifting?
Do the following to prevent most of the back injuries that are due to incorrect
lifting:
• Stand close to the load with your feet spread about shoulder-width
apart, with one foot slightly in front of the other for balance.
• Squat down bending at the knees (not your waist). Tuck your chin while
keeping your back as vertical as possible.
• Get a firm grasp of the object before beginning the lift.
• Begin slowly, lifting with your LEGS by straightening them. Never twist
your body during this step.
• Once the lift is complete, keep the object as close to your body as
possible. As the load's center of gravity moves away from the body,
there is a dramatic increase in the stress to the lumbar region of the
back.
• To place the object below the level of your waist, follow the same
procedure in reverse order.
Did you know?
• An average woman's arm and torso can lift 60 percent as much as a
man's.
• At age 65, the average person's strength is 75 percent of someone who
is 20 or 25, but endurance remains similar.
• Manual material handling accounts for 30-40 percent of the workers'
compensation claims in the United States.
Back Hazards and Occupations
The following shows common back hazards for particular occupations.
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Heavy lifting: Construction workers, manufacturing
Twisting and lifting: Construction workers, Material handlers, assembly
workers
Lifting oddly shaped objects: Construction workers, Hospital workers
(i.e., patients),
Having to reach and lift: Construction workers, Mechanics
Bending and overexerting: construction workers, Maintenance ground
crews
Lifting variable-weight items: Construction workers, Baggage handlers,
movers, and construction workers
Standing/sitting in constant position: Office workers, assembly jobs
Key Point: As you see, almost all back hazards affect construction workers.
This means you should be more careful not to hurt your back when you
perform the above tasks mentioned.
Topic Summary
Please take a moment to review these points before you continue with the
next topic.
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Back pain is caused by anything that puts pressure on your back
muscles and/or nerves.
The disc is the most likely site of a back injury.
Improper lifting techniques exhaust the back muscles.
There are five risk factors for back injuries:
o Poor posture
o Poor physical condition
o Improper body mechanics
o Incorrect lifting
o Jobs that require a high level of energy (physically demanding)
Topic 3: Proper Lifting Techniques
In this topic you will learn about proper lifting techniques. Upon completing
this topic, you will be able to:
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Demonstrate what you should and should not do when you lift
State the principles for reducing the risk of back injury
Identify assisted lifting procedures when there is no way to reduce the
load
Demonstrate less stressful ways of moving loads
Safe Lifting
Before lifting, take a moment to think about what you are about to do.
Examine the object for sharp corners, slippery spots, or other potential
hazards. Know your limit and don't try to exceed it. Ask for help if needed or,
if possible, divide the load to make it lighter. Know where you are going to set
the item down and make sure it and your path are free of obstructions.
When you lift, you should:
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Prepare for the lift by preparing your muscles.
Plant your feet firmly; get a stable base of support.
Bend at your knees, not at your waist.
Tighten your abdominal muscles to support your spine.
Get a good grip and use both hands.
Keep the load you are lifting close to your body.
Use your leg muscles as you lift.
Keep your back straight and try to maintain the natural curve of the
spine.
Lift steadily and smoothly without jerking.
Breathe while lifting. If you have to hold your breath while lifting, it's too
heavy and you need to get help.
Stand close to the load, facing the way you intend to move.
Use a wide stance to gain balance.
Keep the arms straight.
Tuck the chin into the chest.
Do not attempt the lift if you are not convinced that you can handle the
load safely.
Avoid lifting heavy loads if possible. Push or slide the load, if you can, or
use lifting equipment if possible.
Key Point: Wearing a back-support belt will not increase maximum lifting
potential.
You just Learned Do's, What about Don'ts?
When you lift, you should NOT:
• Lift from the floor with the load too low.
• Twist your back while lifting.
• Lift with one hand or with the load unbalanced.
• Lift loads across obstacles, such as over a wall or fence, etc.
• Lift while reaching or stretching.
• Lift from an uncomfortable posture.
• Fight to recover a dropped object.
• Hold your breath while lifting.
Here are some tips to help your body when lifting:
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Stretch Often! And Shift Positions
o Change (shift) your posture often.
o Stretch frequently throughout the day.
o Keep your body flexible (not rigid or flexed); static posture
becomes uncomfortable and decreases productivity.
o Don't force your body to conform to its workspace. Habitually poor
posture will cause increased aches and pains.
o Slow down if you are doing a lot of heavy, repetitive lifting; take it
slowly if you can. Allow yourself more recovery time between lift,
as well.
o Don't overdo it.
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Listen to Your Body! Be Careful!
o Feeling discomfort or pain is an indication that something is wrong.
o Heed the signs...Combinations of awkward posture, force,
repetitions, and insufficient rest periods are a setup for injury.
o Take more frequent breaks before you become too fatigued.
o Stand up and stretch your back, neck, or arms.
o Become aware of mounting stresses, aches, and pains.
o Handle materials carefully.
Principles to Reduce the Risk of Back Injury
If you have to move or lift a load, you must think about your back. Following
the procedure below can help you reduce the risk of back injury.
Assess
Ask these questions: is the task absolutely necessary? Is the load very heavy
or unstable?
Plan
Think about these: How are you going to lift the load? Do you need help or
equipment? Is there enough room for a safe move?
Prepare
Explain to anyone helping what you intend to do. Remove any obstacles from
the environment.
Posture
Keep your spine in line, feet apart, elbows in, knees and hips bent, get close
to the load, and avoid twisting.
Perform
One person should coordinate the move -- "ready, set, go." Aim for a smooth,
flowing movement.
Evaluate
Reflect: Did everything go according to plan? Is there anything that could have
been done to make the move safer?
Checklist:
Before performing any kind of lift, you should assess the situation and
ask yourself these questions...
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Is the load big, bulky, and heavy?
Do you need help? Avoid lifting materials that exceed 1/3-1/2 of
your body weight. GET HELP!
Can you slide it instead of lifting it? PUSH, DON'T PULL!
Must you twist or stretch to get it? Readjust the load or your
position before you lift. Again, GET HELP!
Do you need equipment (e.g., hand truck, forklift, dolly) to help
move it?
Have you stretched your muscles or warmed up before lifting? A
few simple stretches before beginning the task will warm up your
muscles and increase your range of motion and ease of
movements. Stretch again to cool down and decrease potential
stiffness after completing the task. Stretch periodically throughout
the day.
Are you wearing slip-resistant shoes?
Have you cleared a pathway before you move the item?
Is the design of this lifting and handling task ergonomically
correct?
Assisted Lifting
In some cases, there will be no way to reduce the load. When this is the case
and it is not possible to reduce the load or prevent heavy lifting, you should
follow these procedures:
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Use a hoist, crane, or forklift system to assist in the lift and
movement of heavy objects.
Use overhead hoists to pull an object from one location to another.
Provide sufficient time to avoid sudden, jerking motions by the
operator. It is not uncommon for a hoist operator to become injured
by attempting to stop an uncontrolled swinging motion of an object
supported by the hoist.
Use lifting aides such as a rope sling, grappling hooks, suction cups,
and move objects with the help of pneumatic or electric devices.
Use roller conveyors or powered conveyors that pull objects closer to
the body before lifting.
Use gravity-fed slides and shelves.
Moving Loads
Here are some less stressful ways of moving loads:
1. Push/pull using carts, trolleys, or wheelbarrows.
• This is hazardous if an object is too heavy.
• Pulling is more strenuous on the lower back than pushing loads.
• Do not exceed hand force requirements of 50 pounds when hands
can be at hip and waist level.
2. If you have a cart or wheelbarrow:
• Use handles that can be grasped at various points.
• Use large rubber tires and good bearings that do not hang up on
irregular surfaces.
• Use wheels that pivot easily.
• Make sure the cart is designed to handle the intended load.
• Wear shoes with good traction.
• Make sure the floor surface or ground is free of debris.
• When applying force to move the cart or wheelbarrow, place one
foot back to use the large muscles of the legs and back to move
the load, not the arms.
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If moving a high load, make sure the overhead area is clear.
If the load cannot be moved, get help from a coworker.
When carrying a load, is it all right to turn or twist my body as long as I turn
with my torso? No. You should try to minimize any turning or twisting; but if
you must turn while carrying the load, turn using your feet.
Topic Summary
Please take a moment to review these points before you continue with the
next topic.
• When you lift, there are things you should and should not do. Make sure
you follow all the required steps.
• When you have to move or lift a load, you must consider the following
principles:
o Assess
o Plan
o Prepare
o Posture
o Perform
o Evaluate
• When there is no way to reduce the load, you should consider using a
hoist, crane, forklift system, lifting aides, roller conveyor, or gravity-fed
slides and shelves.
• Pushing/pulling using carts, trolleys, or wheelbarrows is a less stressful
way of moving loads.
Topic 4: Controlling Hazards
In this topic you will learn about how to control hazards to the back. Upon
completing this topic, you will be able to:
• Explain OSHA recommendations for controlling common back hazards
• Demonstrate exercises to strengthen muscles
Administrative and Engineering controls can be utilized to eliminate manual
lifting hazards prior to the beginning of operations. Personal protective
equipment (PPE) as a protection device is your last line of defense and this
protects you from manual lifting hazards.
Specific Engineering Controls
Engineering controls can directly involve redesigning the workstation, adapting
equipment, and minimizing awkward movement. Through the use of
engineering controls, one attempts to ergonomically redesign a job to fit the
worker so that tasks such as lifting or bending become less hazardous.
OSHA suggests the following engineering controls:
1. A
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reduction in the size or weight of the object lifted
Maximum allowable weights for a given set of task requirements
The compactness of the objects/materials to be lifted
The presence of handles and the stability of the material being
handled
2. Adjusting the height of the pallet or shelf to bring the object to be lifted
to the proper lifting level, (i.e., above the knee, below the shoulders)
3. Installation of mechanical aids such as pneumatic lifts, conveyors,
and/or automated materials-handling equipment
Specific Administrative Controls
In conjunction with engineering controls, back strain prevention can also be
targeted through administrative controls. These controls focus on minimizing
worker exposure to unsafe conditions through careful training and education
about the mechanics and constraints of the body. Emphasizing physical fitness
and training workers that avoiding loads that exceed their capacities will
prevent the risk of back injury.
However, in some jobs such as construction, police work, and firefighting, it is
difficult to control the ergonomic environment. In these instances OSHA
suggest reliance on administrative controls -- in particular, extensive training
of workers so they can safely perform lifting tasks.
Checklist: Click here to see what supervisors need to do to reduce employees'
back injuries.
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Let employees know that you are concerned about workplace safety and
their health.
Let them know that your expectation is to eliminate job-related
accidents and illnesses.
Be responsive to employees' suggestions, safety committee
recommendations, and other input regarding workplace safety.
Provide ongoing training programs for old and new employees.
Involve your employees in developing a training program for back injury
prevention.
Allow your employees input concerning production and company goals
and some measure of control over the pace of their work.
Have a hand-written return-to-work program.
Contact injured employees as soon as possible following an injury to let
them know you care and to ensure them of their job will be waiting.
Companies that institute return-to-work programs have demonstrated
significant reductions in the number of time-loss claims filed.
Have a written drug and alcohol policy and follow it.
Follow good personnel management regarding hiring, firing, new
employee orientation and performance coaching, and ensure that your
safety results and practices are integrated into these areas.
Make your workplace a positive environment.
Exercises to Strengthen Your Muscles
The following is exercises for strengthening your muscles. Exercise whenever
you are able. If you wish, click the Word icon to print these steps.
Wall
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slides (to strengthen back, hip, and leg muscles):
Stand with your back against the wall and feet shoulder-width apart.
Slide down into a crouch with the knees bent about 90 degrees.
Count to five and slide back up the wall.
Repeat 5 times.
Leg raises to strengthen back and hip muscles:
• Lie on your stomach.
• Tighten the muscles in one leg and raise it from the floor.
• Hold your leg up for the count of 10 and return it to the floor.
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Do the same for the other leg.
Repeat five times on each leg.
Leg raises to strengthen the stomach and hip muscles:
• Lie on your back with your arms at your sides.
• Lift your leg off the floor and hold it up for the count of 10, then return it
to the floor.
• Do the same with the other leg
• Repeat five times on each leg.
Partial sit-up to strengthen stomach muscles:
• Lie on your back with your knees bent and your feet flat on the floor.
• Slowly raise your head and shoulders off the floor and reach with both
hands toward your knees.
• Count to 10 and repeat five times.
Back
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leg swing to strengthen hip and back muscles:
Stand behind a chair with your hands on the back of the chair.
Lift one leg back and up while keeping the knee straight.
Return slowly.
Raise the other leg and return.
Repeat five times with each leg.
Exercises to decrease the strain on your back:
• Lie on your back with your knees bent and your feet flat on the floor.
• Raise your knees toward your chest.
• Place your hands behind your knees and gently pull your knees as close
to your chest as possible.
• Do not raise your head.
• Do not straighten your knees as you lower them.
• Start with five repetitions, several times a day.
Back
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extensions:
Stand with your feet slightly apart.
Place your hands in the small of your back.
Keep your knees straight.
Bend backwards at the waist as far as possible and hold the position for
one or two seconds.
Topic Summary
Please take a moment to review these points before you continue with the
next topic.
• OSHA suggests the following engineering controls:
o A reduction in the size or weight of the object lifted
o Adjusting the height of the pallet or shelf to bring the object to be
lifted to the proper lifting level
o Installation of mechanical aids such as pneumatic lifts, conveyors,
and/or automated materials-handling equipment
• In some jobs, such as construction, police work, and firefighting, it is
difficult to control the ergonomic environment. In these instances OSHA
suggests reliance on administrative controls -- in particular, extensive
training of workers so they can safely perform lifting tasks.
Lesson Summary
This lesson contains information and instruction about manual lifting. By
completing this lesson, you should have the knowledge to discuss the following
topics. Take a moment to see if you can do the following:
• Describe the anatomy of the back
• Identify causes of back pain and five risk factors for back injuries
• Demonstrate proper lifting techniques
• State specific engineering and administrative controls that OSHA
suggests
Tools
Introduction
Two employees were engaged in remodeling construction work.
One of the workers was killed when the tool operator, while attempting to
anchor plywood to a 2" x 4" stud, fired a nail from a powder-actuated tool and
struck him. The nail penetrated the stud and the plywood partition before
striking the victim.
As a result of its investigation, OSHA issued citations for three serious
violations. Had employees been trained in the use of powder-actuated tools
and taken precautions to prevent the nail from passing through the wall, the
accident probably would not have occurred.
Lesson Overview
This lesson introduces construction tools and their hazards and controls. You
will learn how to select, use, and maintain a variety of tools safely.
Upon completing this lesson, you will be able to:
• Recognize tool hazards and apply the control hierarchy principles
• Identify and demonstrate safe practices for using hand and power tools
• Control a variety of power-operated tools effectively and safely
• Practice safety measures using these specific tools: portable circular
saws, portable drills, sanders, cordless power tools, woodworking tools,
and jacks
Why Learn This Lesson?
Tools are such a common part of our lives that it is difficult to remember that
they may pose hazards. All tools are manufactured with safety in mind, but a
serious accident often occurs before steps are taken to search out and avoid or
eliminate tool-related hazards.
In the process of removing or avoiding the hazards, workers must learn to
recognize the hazards associated with the different types of tools and the
safety precautions that prevent those hazards.
The large variety of hand and portable power tools available on the market
today is mind-boggling. These tools allow us to work faster and increase the
number of different jobs that we can accomplish. However, if used improperly,
hand and power tools can cause injury.
The information in the lesson will help you control and manage the hazards of
hand and power tools effectively.
Topic 1: Hazards & Controls
This topic introduces a control methodology for safe operation of hand and
power tools. Upon completing this topic, you will be able to:
• Recognize the need for tool safety
• Discuss engineering, administrative, and personal protective equipment
as the preferred order of controlling the proper use of tools
• Identify the safety materials recommended for personal protective
equipment
• Apply the five basic safety rules when using tools
Hazard Recognition
Tools are such a common part of our lives that it is easy to forget that they
pose hazards. All tools are manufactured with safety in mind but, tragically, a
serious incident often occurs before steps are taken to search out and avoid or
eliminate tool-related hazards.
To remove or avoid hazards, workers must learn to recognize the hazards
associated with the different types of tools and the safety precautions
necessary to prevent those hazards.
Hazard Prevention
Reducing the risks associated with construction work is very important. To
meet this goal, there is a hierarchy, or preferred order, of control. These
controls are not mutually exclusive, and there may be occasions when more
than one control must be used to reduce a risk. However, prevention is best
served by implementing your hierarchy or control methodology before you
start any construction operation.
1. Engineering controls
2. Administrative controls
3. Personal protective equipment
By using controls, including protective equipment and proper work practices,
you can operate hand and power tools safely and with confidence.
Administrative and engineering controls can be used to eliminate fall hazards
prior to the beginning of operations. Personal protective equipment (PPE) as a
protection device is your last line of defense and protects you from fall
hazards.
Engineering Controls
Engineering controls, which attempt to eliminate hazards, do not necessarily
require an engineer to design them. Engineering controls can be very simple.
To the extent feasible, the work environment and the job itself should be
designed to eliminate or reduce exposure to hazards based on the following
principles:
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If feasible, design the job site, equipment, or process to remove the
hazard or substitute something that is not hazardous or is less
hazardous.
If removal is not feasible, enclose the hazard to prevent exposure in
normal operations.
Where complete enclosure is not feasible, establish barriers to reduce
exposure to the hazard in normal operations.
Administrative Controls
Administrative controls normally are used in conjunction with other controls
that more directly prevent or control exposure to hazards. They include
lengthened rest breaks, additional relief workers, exercise breaks to vary body
motions, and rotation of workers through different jobs to reduce stress or
repetitive motions on one part of the body. Administrative controls also include
work practices that reduce risk by:
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Limiting the amount of time a person is exposed to a particular hazard
Implementing and documenting safe working procedures for all
hazardous tasks
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Training and instructing all personnel
Identifying hazards prior to starting work
Personal Protective Equipment
The last method of control is the use of personal protective equipment (PPE),
and it should be considered only when other control measures are not
practicable or to increase a person's protection as an additional measure. PPE
includes:
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Hard hats
Eye protection
Fall-arrest harnesses and lanyards
Foot protection
Hand protection
Respirators
Hearing protection
Personal Protective Equipment
Personal protective equipment as a protection device is your last line of
defense to protect you from tool hazards.
Power tools present more hazards than hand tools due to the speed at which
they operate. Although similarities exist, there are distinct differences between
the PPE suggested for use with hand tools and the PPE recommended for safe
power tool use. The type of PPE you need when using hand tools depends on
the tool being used.
Head Protection
A protective helmet is required when working in an area where there is a
potential for injury from falling objects and/or electrical shock.
Eye Protection
At a minimum, eye protection in the form of safety glasses or goggles must be
worn at all times. Others working around the area where power tools are used
should wear protective eyewear also.
Eye protection is especially important when using power tools. The speed in
which drills, saws, grinders, sanders, and routers operate can propel small
particles much faster and farther than can hand tools.
Certain power tools may require using a face shield in addition to safety
glasses or goggles. For example, a face shield is recommended while using a
grinder, due to the amount of hot metal particles generated. The simple act of
snipping copper wire with side-cutting pliers, striking a nail with a hammer, or
sawing wood can propel small pieces of debris into the air.
Hand Protection
It is also important to protect your hands from cuts, abrasion, and repeated
impact. Standard cotton or leather work gloves can protect your hands from
wood splinters, skin abrasions, and minor scrapes and cuts when handling
lumber. Unfortunately, cut-resistant gloves are not designed for, or even
capable of, providing protection against a moving blade or bit. Cut-resistant
gloves made of Kevlar(r), Spectra(r), or stainless steel can help protect
against a misplaced blade.
The best way to prevent injury from moving parts is to keep your hands on
the tool's handles and keep all guards in place. On jobs that require long
periods of hammering, anti-vibration gloves minimize the vibration created by
hammerdrills and rotary hammerdrills. Impact-resistant gloves with gel or
rubber palms can reduce vibration also.
Foot Protection
Safety shoes with a reinforced toe help protect your feet from injury caused by
a dropped tool. Safety footwear comes in a variety of styles and is widely
available.
Choose footwear that offers adequate traction for your work site. Safety
footwear is recommended when using power tools, because power tools are
heavy and they can cut. Safety shoes with a nonslip, insulated sole and a steel
toe protect against dropped objects and misdirected electricity.
Hearing Protection
The sound generated by some power tools, especially if used over extended
periods of time, may require the use of earplugs or earmuffs. Each situation
must be analyzed to determine the type of PPE that is required for the safe
use of each type of power tool.
Clothing
Along with PPE, proper attire is also important while using power tools. Avoid
loose clothing to avoid being caught in moving blades. Also, long hair should
be tied back or covered for the same reason; remove all jewelry as well.
Respirator Protection
Any operation that generates harmful airborne levels of dusts, fumes, sprays,
mists, fogs, smokes, vapors, or gases or that may involve oxygen-deficient
atmospheres requires the use of either an atmosphere-supply respirator or an
air-purifying respirator.
General Safety Precautions
Employees who use hand and power tools and who are exposed to the hazards
of falling, flying, abrasive, or splashing objects or harmful dusts, fumes, mists,
vapors, or gases must be provided with the personal equipment necessary to
protect them from the hazard.
All hazards involved in the use of tools can be prevented by following five
basic safety rules:
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Keep all tools in good condition with regular maintenance
Use the right tool for the job
Examine each tool for damage before use
Operate according to the manufacturer's instructions
Provide and use the proper protective equipment
Employees and employers have a responsibility to work together to establish
safe working procedures. If a hazardous situation is encountered, it should be
brought to the attention of the supervisor immediately.
Topic Summary
Please take a moment to review these major points before you continue with
the next topic.
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Workers must learn to recognize and prevent the hazards associated
with using different tools.
The hierarchy of controls is (1) engineering controls, (2) administrative
controls, and (3) personal protective equipment.
Depending on the tools being used, workers may be required to use a
variety of personal protective equipment.
There are five basic tool safety rules:
o Keep all tools in good condition with regular maintenance.
o Use the right tool for the job.
o Examine each tool for damage before use.
o Operate according to the manufacturer's instructions.
o Provide and use the proper protective equipment.
Topic 2: Hand and Power Tool Safety
Although it is important to recognize the hazards of misusing tools and how to
apply the control hierarchy, it is imperative that you demonstrate safe tool use
to prevent accidents. In this topic you will learn the specific safety practices
for hand and power tools, including the proper use of their accessories. Upon
completing this topic, you will be able to:
• Recognize the safe use and maintenance of hand tools
• Recognize the safe use and maintenance of power tools
• Describe the safeguards for using accessories, tool guards, and safety
switches
• Utilize the training checklist to evaluate your safety compliance
Hand Tools
Hand tools are non-powered. They include anything from axes to wrenches.
The employer is responsible for the safe condition of tools and equipment used
by employees, but the employees have the responsibility for properly using
and maintaining tools. Here are general guidelines:
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Employers should caution employees to direct saw blades, knives, or
other tools away from aisle areas and other employees working in close
proximity.
Knives and scissors must be sharp. Dull tools can be more hazardous
than sharp ones.
Appropriate personal protective equipment (e.g., safety goggles, gloves,
etc.) should be worn due to hazards that may be encountered while
using portable power tools and hand tools.
Safety requires that floors be kept as clean and dry as possible to
prevent accidental slips with or around dangerous hand tools.
Around flammable substances, sparks produced by iron and steel hand
tools can be a dangerous ignition source. Where this hazard exists,
spark-resistant tools made from brass, plastic, aluminum, or wood will
provide for safety.
What are some examples of using tools incorrectly?
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Using a screwdriver as a chisel may cause the tip of the screwdriver to
break and fly, hitting the user or other employees.
If a wooden handle on a tool such as a hammer or an axe is loose,
splintered, or cracked, the head of the tool may fly off and strike the
user or another worker.
A wrench must not be used if its jaws are sprung, because it might slip.
Impact tools such as chisels, wedges, or drift pins are unsafe if they
have mushroomed heads. The heads might shatter on impact, sending
sharp fragments flying.
Hand Tool Safety
As described, the greatest hazards posed by hand tools result from misuse and
improper maintenance. Select each tool on the pegboard to review its safety
dos and don'ts.
Screwdrivers
Screwdrivers are intended for turning a variety of threaded fasteners, such as
machine or wood screws, in or out of materials. Screwdriver tips come in a
variety of different shapes and sizes. The slotted and Phillips(r) tips are the
most common; however, torx, hex, square, and various others are used also.
As with any tool, it is important to match the screwdriver to the job you're
doing.
Dos
• Use a screwdriver tip that properly fits the slot of the screw.
• Throw away screwdrivers with broken or worn handles.
• Turn power off and use electrically insulated screwdrivers when
working on or around electrical components.
• Straighten tips or redress rounded edges with a file.
• Use magnetic or screw-holding screwdrivers to start fasteners in tight
areas.
• Use both hands when using a screwdriver -- one to guide the tip and
the other to turn the handle.
• Use both hands on the screwdriver handle for final tightening.
• Use nonsparking screwdrivers in the presence of flammable vapors or
dusts.
Don'ts
• Never use a screwdriver as a pry bar, chisel, punch, stirrer, or
scraper.
• Never expose screwdrivers to temperatures that could reduce tip
hardness.
• Never use pliers on a screwdriver for extra leverage. Use a wrench
only on screwdrivers specifically designed to accept them.
Wrenches
Wrenches come in an endless variety of styles, such as socket, open-end,
combination, adjustable, and torque, just to name a few. Wrenches are
designed to turn or hold bolts, nuts, or multiple-threaded fasteners. They are
sized to keep the leverage and load in an acceptable balance.
Dos
• Choose a wrench that properly fits the fastener you wish to turn. Use
metric wrenches for metric bolts and American inch wrenches for
inch-sized bolts. By using the correct size, the wrench is less prone to
slip or round off the fastener corners.
• Apply penetrating oil on frozen fasteners before using a striking face
box, socket, or heavy-duty box wrench.
• Pull on a wrench (instead of pushing) in case the fastener loosens.
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Adjustable wrenches must be adjusted tightly to the fasteners and
then pulled, putting the force on the fixed end.
Turn power off and use electrically insulated wrenches when working
on or around electrical components.
Inspect wrenches periodically for damage, such as cracking, severe
wear, or distortion.
Use nonsparking wrenches around flammable vapors or dust.
Don'ts
• Do not expose a wrench to temperatures that could weaken tool
hardness.
• Never alter a wrench.
• Do not over-torque a fastener. Use a torque wrench to tighten the
fastener to the exact torque required.
• Do not use open-end or adjustable wrenches for final tightening or for
loosening frozen fasteners. These wrenches do not have the strength of
a box-end or socket wrench.
• Avoid using an extension to improve the leverage of a wrench.
PLIERS
Pliers come in all shapes and sizes, such as lineman, diagonal cutting, needle
nose, slip joint, locking tongue and groove. Pliers' uses include gripping,
cutting, turning, and bending. Pliers are a versatile tool, but they must be
used according to how they are designed.
Dos
• Cut hardened wire only with pliers designed for that purpose.
• Be sure the pliers' jaws can grasp properly when bending rigid wire.
• Cut wire at right angles without bending wire back and forth against
the cutting edge of the pliers.
• Use non-sparking pliers around flammable vapors or dust.
Don'ts
• Do not hammer with pair of pliers.
• Do not substitute pliers for a wrench when turning nuts and bolts.
• Do not increase a pliers' handle length to gain more leverage;
instead, choose larger pliers.
• Never subject pliers to temperatures that could decrease tool
hardness.
HAMMERS AND STRIKING TOOLS
Hammers are one of the most used tools in our toolboxes (unfortunately, they
are also the most abused tools). Nail, soft-face, ball-peen, chipping, sledge,
and setting are just a few of the hammers we use in the workplace and home.
Many hammer types are specific to a particular industry, such as bricklaying,
machining, and logging. Each kind of hammer has a head that is tailored to
work best for a particular application. Recently, even hammer handles have
been improved to be stronger and ergonomically shaped to transmit less shock
to the user.
Dos
• Use a hammer of the proper weight and size for the task.
• Use a hammer face that is 3/8" larger in diameter than the striking tool.
• Remove from service any hammer exhibiting signs of excessive wear,
cracks, mushrooming, or chips.
• Use non-sparking hammers around flammable vapors or dust.
Don'ts
• Do not use one hammer to strike another.
• Do not use the wrong hammer for the job; match the hammer to the
task it is designed to perform.
• Do not strike the surface at an angle. The hammer face should contact
the striking surface squarely, so the two are parallel.
• Do not use a hammer if the handle is damaged or loose.
• Never weld, heat, or regrind a hammer head.
Power Tools
Today's power tools offer more power, adaptability, and dependability than
ever before. Portable power tools are designed for a wide variety of uses.
Circular saws, jigsaws, drills, hammerdrills, sanders, grinders, routers, and
numerous other power tools save us time and effort on the job.
But along with enhanced tool performance comes the responsibility to address
power tool safety issues. Power tools can be hazardous when improperly used.
Workers responsible for specifying and using power tools also have a
responsibility to check out a tool's safety features. Supervisors must also
ensure that manufacturer safety precautions and common sense are followed
at all times.
The information in this section offers general safety guidelines for power tools,
as well as guidelines for specific tools. They are not an absolute or complete
presentation of safety measures and procedures that relate to use of power
tools. The manuals that manufacturers ship with tools and accessories are
always recommended as a best source for proper procedures for specific tool
use.
Know the Power Tool
Operators must select a tool based on the task it is designed to do and read
and understand the owner's manual on that tool. Know tool applications and
limitations. Labels affixed to the tool or included in the shipping container
must be read and understood.
• Use only attachments specifically recommended for your power tools and
ensure their proper installation.
• Avoid excessive force to make cutting tools cut faster.
• Avoid accidental starting. The worker should not hold a finger on the
switch button while carrying a plugged-in tool.
• Secure work with clamps or a vise, freeing both hands to operate the
tool.
Ground All Tools Unless Double Insulated
Where a tool is equipped with a three-prong plug, it must be plugged into a
three-hole electric receptacle known to be grounded. If an adapter is used to
accommodate a two-hole receptacle, attach the adapter with a screw to a
known ground.
Avoid Dangerous Environments
• Do not use power tools in a damp, wet, or explosive atmosphere; avoid
fumes, dust, or flammable materials.
• Protect yourself from electric shock by ensuring that your tools are
properly grounded; use a ground fault circuit interrupter for corded
tools.
• Keep observers at a safe distance from the work area or provide shields
to stop flying debris and other distractions.
Be Aware of Mechanical Hazards
Be aware of all power lines and electrical circuits, water pipes, and other
mechanical hazards in your work area, particularly those below the work
surface and hidden from the operator's view. In addition, inspect tools for
damage, including the cord, presence of guards, correct alignment, binding of
components, or any condition that would affect the operation of the tool.
Maintain Tool Control
When using power tools, keep a tight grip on the tool and maintain your
balance; plus, do not overreach. Also, do not operate a power tool if you are
under the influence of medications or alcohol or if you are tired or distracted.
Plug/Unplug Cords Safely
• Disconnect tools when not in use, before servicing, and when changing
accessories such as blades, bits, and cutters.
• Never carry a tool by the cord or hose.
• Never yank the cord or the hose to disconnect it from the receptacle.
• Tighten and remove any adjustment keys before use.
Wear Proper Apparel
Do not wear loose clothing, dangling objects, or jewelry. Long hair must be
pulled back. Gloves should not be worn when operating certain power tools.
Check appropriate tool manuals.
Maintain Tools With Care
• Tools should be maintained with care. They should be kept sharp and
clean for the best performance. Follow instructions in the user's manual
for lubricating and changing accessories.
• If a tool is damaged, or a condition develops while a tool is in use, have
the tool fixed before putting it back into service.
• All portable electric tools that are damaged shall be removed from use
and tagged "Do Not Use."
Accessories, Guards, Switches
A variety of accessories, tool guards, and safety switches are available to use
on or with power tools. Caution must be exercised when selecting any of these
tool aids. Selecting the wrong aid or using it improperly may result in serious
injury.
You should not use any power tool accessory or attachment unless:
• The power tool manufacturer recommends its use on the product
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The accessory limitations and specifications -- such as speed, size,
mounting, and guarding requirements, etc. -- match the limitations and
specifications of the power tool as shown in the owner/operator's manual
The accessory does not require the removal of or defeating of any
guards, barriers, or other safety-related devices on the power tool,
unless other appropriate guards or protective devices replace them
Also, unplug tools before installing, adjusting, and changing any
accessory or attachment of any kind.
TOOL GUARDS
Hazardous moving parts of a power tool need to be safeguarded. For example,
belts, gears, shafts, pulleys, sprockets, spindles, drums, fly wheels, chains, or
other reciprocating, rotating, or moving parts must be guarded if such parts
are exposed to contact by employees.
Guards, as necessary, should be provided to protect the operator and others
from the following:
• Point of operation
• In-running nip points
• Rotating parts
• Flying chips and sparks
Safety guards must never be removed when a tool is being used. For example,
portable circular saws must be equipped with guards. An upper guard must
cover the entire blade of the saw. A retractable lower guard must cover the
teeth of the saw, except when it makes contact with the work material. The
lower guard must return to the covering position automatically when the tool
is withdrawn from the work.
There are some specific guarding requirements for individual tools that will be
covered later in this lesson.
SAFETY SWITCHES - Momentary
The following hand-held power tools must be equipped with a momentary
contact "on-off" control switch:
• Drills
• Tappers
• Fastener drivers
• Horizontal, vertical, and angle grinders with wheels larger than two
inches in diameter
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Disc and belt sanders
Reciprocating saws
Saber saws
These tools also may be equipped with a lock-on control, provided that a
single motion of the same finger or fingers that turn it on can accomplish
turnoff.
SAFETY SWITCHES- Positive
The following hand-held power tools may be equipped with only a positive "onoff" control switch:
• Platen sanders
• Disc sanders with discs two inches or less in diameter
• Grinders with wheels two inches or less in diameter
• Routers
• Planers
• Laminate trimmers
• Nibblers
• Shears
• Scroll saws
• Jigsaws with blade shanks 1/4-inch wide or less
Other hand-held power tools, such as circular saws having a blade diameter
greater than 2 inches, chain saws, and percussion tools without positive
accessory holding means, must be equipped with a constant pressure switch
that will shut off the power when the pressure is released.
Topic Summary
Please take a moment to review these key points before you continue with the
next topic.
• Manufacturers' manuals are the best source for proper procedures for
specific tool use.
• Eight common safety rules apply to all power tools:
o Know the power tool
o Ground all tools unless double insulated
o Avoid dangerous environments
o Be aware of mechanical hazards
o Maintain tool control
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o Unplug/plug cords safely
o Wear proper apparel
o Maintain tools with care
Give careful consideration to safety requirements when selecting
accessories/attachments, tool guards, and safety switches.
Always use the training checklist to verify your tool safety compliance.
Topic 3: Types of Tools
This topic explains the different types of power-operated tools. From electrical
to powder-actuated, you will learn the chief hazards and preventions for
working with all power-operated tools on the job site. In addition, you will
learn specific safety usage of common tools used on construction sites. Upon
completing this topic, you will be able to:
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Control a variety of power-operated tools effectively and safely
Identity the specific hazards and safety practices for common tools
Power-Operated Tools
ELECTRIC TOOLS
Hazards
Employees using electric tools must be aware of several dangers, the most
serious of which is the possibility of electrocution.
Among the chief hazards of electric-powered tools are burns and slight shocks,
which can lead to injuries or even heart failure. Under certain conditions, even
a small amount of current can result in fibrillation of the heart and eventual
death. A shock also can cause the user to fall off a ladder or other elevated
work surface.
Control
To protect the user from shock, tools must be grounded by a three-wire cord,
be double insulated, or be powered by a low-voltage isolation transformer.
Three-wire cords contain two current-carrying conductors and a grounding
conductor. One end of the grounding conductor connects to the tool's metal
housing. The other end is grounded through a prong on the plug. Any time an
adapter is used to accommodate a two-hole receptacle, the adapter wire must
be attached to a known ground. The third prong should never be removed
from the plug.
Double insulation is more convenient. The user and the tools are protected in
two ways: by normal insulation on the wires inside, and by a housing that
cannot conduct electricity to the operator in the event of a malfunction.
These general practices should be followed when using electric tools:
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Electric tools should be operated within their design limitations.
Gloves and safety footwear are recommended during use of electric
tools.
When not in use, tools should be stored in a dry place.
Electric tools should not be used in damp or wet locations.
Work areas should be well lighted.
POWERED ABRASIVE WHEEL TOOLS
Hazards
Powered abrasive grinding, cutting, polishing, and wire buffing wheels create
special safety problems because they may throw off fragments.
Control
Inspecting Wheels
Before an abrasive wheel is mounted, it should be inspected closely and
sound- or ring-tested to be sure that it is free from cracks or defects. To test,
wheels should be tapped gently with a light non-metallic instrument. If they
sound cracked or dead, they could fly apart in operation and so must not be
used. A sound and undamaged wheel will give a clear metallic tone or "ring."
Wheel Maintenance
To prevent the wheel from cracking, the user should be sure it fits freely on
the spindle. The spindle nut must be tight enough to hold the wheel in place
without distorting the flange. Follow the manufacturer's recommendations.
Care must be taken to assure that the spindle wheel will not exceed the
abrasive wheel specifications.
Because of the possibility of a wheel disintegrating (exploding) during startup, the employee should never stand directly in front of the wheel as it
accelerates to full operating speed.
Grinding Tools
Portable grinding tools need to be equipped with safety guards to protect
workers not only from the moving wheel surface, but also from flying
fragments in case of breakage. In addition, when using a powered grinder:
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Always use eye protection
Turn off the power when not in use
Never clamp a hand-held grinder in a vise
PNEUMATIC TOOLS
Hazards
Pneumatic tools are powered by compressed air and include chippers, drills,
hammers, and sanders.
There are several dangers encountered in the use of pneumatic tools. The
main one is the danger of being hit by one of the tool's attachments or by
some kind of fastener the worker is using with the tool. Noise is another
hazard. Working with noisy tools such as jackhammers requires proper,
effective hearing protection.
Control
* Eye protection is required and face protection is recommended for
employees working with pneumatic tools.
* When using pneumatic tools, employees must check to see that they are
fastened securely to the hose to prevent them from becoming disconnected.
* A short wire or positive locking device attaching the air hose to the tool will
serve as an added safeguard.
* A safety clip or retainer must be installed to prevent attachments, such as
chisels on a chipping hammer, from being shot from the barrel unintentionally.
* Screens must be set up to protect nearby workers from being struck by
flying fragments around chippers, riveting guns, staplers, or air drills.
* Compressed air guns should never be pointed toward anyone. Users should
never "dead-end" it against themselves or anyone else.
FUEL-POWERED TOOLS
Hazard
The use of fuel-powered tools exposes the employee to hazardous vapors.
There is also the risk of fire, explosion, or hazardous chemical spills.
Control
All fuel-powered tools must be stopped while being refueled, serviced, or
maintained, and fuel must be transported, handled, and stored in accordance
with OSHA regulations.
When fuel-powered tools are used in enclosed spaces, follow the applicable
requirements for concentrations of toxic gases and use of personal protective
equipment.
HYDRAULIC POWER TOOLS
Hazards
There is a serious hazard of fire and explosion when hydraulic powered tools
are used.
Control
The fluid used in hydraulic powered tools must be approved, fire-resistant
fluids and must retain its operating characteristics at the most extreme
temperatures to which it will be exposed.
The manufacturer's safe operating pressures for hoses, valves, pipes, filters,
and other fittings must not be exceeded.
PNEUMATIC POWER TOOLS
Hazards
There is a hazardous exposure that can result from disconnection, expelling
hoses and whips. In addition, the discharge can create flying particles.
Control
Secure Devices
* Pneumatic power tools must be secured to the hose or whip by some
positive means to prevent the tool from becoming accidentally disconnected.
* Safety clips or retainers must be securely installed and maintained on
pneumatic impact (percussion) tools to prevent attachments from being
accidentally expelled.
* All pneumatically driven nailers, staplers, and other similar equipment
provided with automatic fastener feed, and which operate at more than 100
pounds per square inch (psi) at the tool, must have a safety device on the
muzzle to prevent the tool from ejecting fasteners, unless the muzzle is in
contact with the work surface.
Compressed Air
* Compressed air must not be used for cleaning purposes except where
reduced to less than 30 psi, and then only with effective chip guarding and
personal protective equipment that meets OSHA requirements.
* The 30 psi requirement does not apply to concrete form, mill scale, and
similar cleaning purposes.
* The manufacturer's safe operating pressure for hoses, pipes, valves, filters,
and other fittings must not be exceeded.
* The use of hoses for hoisting or lowering tools must not be permitted.
* All hoses exceeding 1/2-inch inside diameter must have a safety device at
the source of supply or branch line to reduce pressure in case of hose failure.
Airless Spray Guns
* Airless spray guns that atomize paints and fluids at high pressures (1,000
pounds or more per square inch) must be equipped with automatic or visible
manual safety devices that will prevent release of the paint or fluid until the
safety device is manually released.
* In lieu of the above, a diffuser nut, which will prevent high pressure, high
velocity release while the nozzle tip is removed, plus a nozzle tip guard that
will prevent the tip from coming into contact with the operator, or other
equivalent protection, must be provided.
* Abrasive blast cleaning nozzles must be equipped with an operating valve,
which must be held open manually.
* A support shall be provided on which the nozzle may be mounted when it is
not in use.
POWDER-ACTUATED TOOLS
Hazards
Powder-actuated tools operate like a loaded gun and should be treated with
the same respect and precautions. In fact, they are so dangerous that only
specially trained employees must operate them.
Control
Maintenance
* Before using the tool, the worker should inspect it to determine that it is
clean, that all moving parts operate freely, and that the barrel is free from
obstructions.
* Any tool found not in proper working order, or that develops a defect during
use, must be removed from service immediately.
Operations
* Only employees who have been trained in the operation of the particular tool
in use must be allowed to operate a powder-actuated tool.
* To prevent the tool from firing accidentally, two separate motions are
required for firing: one to bring the tool into position, and another to pull the
trigger.
* Tools must not be loaded until just prior to the intended firing time, and
neither loaded nor empty tools are to be pointed at any employees.
* The tools must not be able to operate until they are pressed against the
work surface with a force of at least 5 pounds greater than the total weight of
the tool.
* If a powder-actuated tool misfires, the employee should wait at least 30
seconds, then try firing it again. If it still will not fire, the user should wait
another 30 seconds so that the faulty cartridge is less likely to explode, and
then carefully remove the load. The bad cartridge should be put in water.
* All tools must be used with the correct shield, guard, or attachment
recommended by the manufacturer.
* Driving into materials easily penetrated must be avoided unless such
materials are backed by a substance that will prevent the pin or fastener from
passing completely through and creating a flying missile hazard on the other
side.
Precautions
* Suitable eye and face protection is essential when using a powder-actuated
tool.
* The muzzle end of the tool must have a protective shield or guard centered
perpendicular to the barrel to confine any flying fragments or particles that
might otherwise create a hazard when the tool is fired.
* The tool must be designed so that it will not fire unless it has this kind of
safety device.
* All powder-actuated tools must be designed for varying powder charges so
that the user can select a powder level necessary to do the work without
excessive force.
* Loaded tools must not be left unattended, especially where it would be
available to unauthorized persons.
Fasteners
* Fasteners must not be driven into very hard or brittle materials including,
but not limited to, cast iron, glazed tile, surface-hardened steel, glass block,
live rock, face brick, or hollow tile.
* No fastener must be driven into a spalled area caused by an unsatisfactory
fastening.
Topic Summary
Please take a moment to review these key points before you continue with the
next topic.
• When using electrical tools, always wear PPE and work in a dry place.
• Powered abrasive wheel tools should be safeguarded against flying
fragments.
• Protect yourself from being hit by an attachment or fastener when using
pneumatic tools.
• When using fuel-powered tools, consider the concentration of toxic
gases.
• The fluid in hydraulic powered tools must be an approved, fire-resistant
fluid.
• Secure pneumatic power tools to the hose and whip to prevent
accidentally disconnecting.
• Only specially trained employees can operate powder-actuated tools,
because these tools are as dangerous as a loaded gun.
PORTABLE CIRCULAR SAWS
In the construction industry, the circular saw is probably one of the most
commonly used power tools and perhaps the most commonly abused.
Familiarity should not breed carelessness.
The following are specific safety musts when using any portable circular saws.
Protection
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Always wear safety goggles or safety glasses with side shields that
comply with the current national standard and a full-face shield when
needed. Use a dust mask in dusty work conditions. Wear hearing
protection during extended periods of operation.
Don't wear loose clothing, jewelry, or dangling objects, including long
hair that may catch in rotating parts or accessories.
Operations
• Don't use a circular saw that is too heavy for you to easily control.
• Be sure the switch actuates properly. It should turn the tool on and
return to the off position after release.
• For maximum control, hold the saw firmly with both hands after securing
the work piece. Clamp work pieces. Check frequently to be sure clamps
remain secure.
• Before starting a circular saw, be sure the power cord and extension
cord are out of the blade path and are long enough to complete the cut
freely. Keep aware of the cord location. A sudden jerk or pulling on the
cord can cause loss of control of the saw and a serious accident.
• When you start the saw, allow the blade to reach full speed before
contacting the work piece.
Blades
• Use sharp blades. Dull blades cause binding, stalling, and possible
kickback. They also waste power and reduce motor and switch life.
• Use the correct blade for the application. Check this carefully. Does it
have the proper size and shape arbor hole? Is the speed marked on the
blade at least as high as the no-load RPM on the saw's nameplate?
• Is the blade guard working? Check for proper operation before each cut.
Check often to ensure that guards return to their normal position
quickly. If a guard seems slow to return or hangs up, repair or adjust it
immediately. Never defeat the guard to expose the blade by, for
example, tying it back or removing it.
Cutting
• Avoid cutting small pieces that can't be properly secured and material on
which the saw shoe can't properly rest.
• When making a partial cut, or if power is interrupted, release the trigger
immediately and don't remove the saw until the blade has come to a
complete stop.
PORTABLE DRILLS
Available in a variety of types and capacities, portable power drills are
undoubtedly the most used power tools. Because of their handiness and
application to a wide range of jobs, drills often receive heavy use. For this
reason, you'll need to check your drill's capacity limitations and accessory
recommendations with care. For example:
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Check carefully for loose power cord connections and frays or damage to
the cord. Replace damaged tool and extension cords immediately.
Be sure the chuck is secured tightly to the spindle. This is especially
important on reversible drills.
Tighten the bit securely as prescribed by the owner/operator's manual.
The chuck key must be removed from the chuck before starting the drill.
A flying key can be an injury-inflicting missile.
Check auxiliary handles if part of the tool. Be sure they are securely
installed. Always use the auxiliary drill handle when provided. It gives
you more control of the drill, especially if stalls occur. Grasp the drill
firmly by insulated surfaces.
Always hold or brace the tool securely. Brace against stationary objects
for maximum control. If drilling in a clockwise (forward) direction, brace
the drill to prevent a counterclockwise reaction.
Don't force a drill. Apply enough pressure to keep the drill bit cutting
smoothly. If the drill slows down, relieve the pressure. Forcing the drill
can cause the motor to overheat, damage the bit, and reduce operator
control.
SANDERS
Sanding is often a prolonged operation, so to make sure that the working
environment is correct. Consider these safety points:
• Stationary sanders may incorporate belt and disc sanding features.
Portable sanders are normally single-feature sanders -- disc, pad, or
belt. Use caution and be alert to avoid injuries that result from
contacting the sanding medium or other moving parts.
• Always wear safety goggles or safety glasses with side shields complying
with the current national standard and a full-face shield when needed.
Use a dust mask in dusty work areas. Sanding dust may affect your
breathing and overcome you if you are not protected against it,
particularly when working with many of the exotic hardwoods.
• Adequate ventilation of your work area is very important when using any
type of sander. The use of exhaust type systems or bag collection is also
recommended. Dust can explode if the concentration becomes too great.
MITER BOX SAWS AND CHOP SAWS
• Because of the saw's downward cutting motion, keep hands and fingers
away from the blade's path.
• Be sure all guards are in place and working. If a guard seems slow to
return to its normal position, adjust or repair it immediately.
• Use only recommended size and RPM-rated blades.
• When installing or changing a blade, be sure the blade and related
washers and fasteners are correctly positioned and secured on the saw
arbor.
CORDLESS POWER TOOLS
Cordless tools get their power from batteries, but they require the same
amount of precaution that corded tools receive.
The following recommendations do not apply to the cordless tools themselves,
but do apply to their chargers.
• If a cordless tool is connected to its recharge unit, both pieces of
equipment must conform strictly with electrical recommendations in the
manufacturer's instruction manual.
• Perform charging in a dry location, away from combustible materials.
• If the battery of the tool no longer charges properly with its specified
recharge unit, return the tool and the charger to your distributor service
center as listed in the Yellow Pages or your tool's instruction manual.
• Do not operate cordless tools in or near flammable liquids or in gaseous
or explosive atmospheres. Motors in these tools normally spark, and the
sparks may ignite fumes.
• Always recharge a cordless tool and its battery with its own specified
charging unit. Never attempt to recharge a cordless tool in a recharging
unit not specifically recommended by the manufacturer for that tool or
battery pack.
• Be aware that a cordless tool can always be in an operating condition
because it does not have to be plugged into an electrical outlet. Unless
batteries are removed, the tool can function any time the switch is on.
• Do not expose the battery cartridge to moisture, frost, or temperature
extremes over 100 C degrees or under -20 C.
WOODWORKING TOOLS
All power-driven woodworking tools must be provided with a disconnect switch
that either can be locked or tagged in the off position.
The operating speed must be etched or otherwise permanently marked on all
circular saws over 20 inches in diameter or operating at over 10,000
peripheral feet per minute.
Any saw so marked must not be operated at a speed other than that marked
on the blade. When a marked saw is retensioned for a different speed, the
marking must be corrected to show the new speed.
Automatic feeding devices must be installed on machines whenever the nature
of the work will permit. Feeder attachments must have the feed rolls or other
moving parts covered or guarded to protect the operator from hazardous
points.
All portable, power-driven circular saws must be equipped with guards above
and below the base plate or shoe. The upper guard must cover the saw to the
depth of the teeth, except for the minimum arc required to permit the base to
be tilted for bevel cuts. The lower guard must cover the saw to the depth of
the teeth, except for the minimum arc required to allow proper retraction and
contact with the work. When the tool is withdrawn from the work, the lower
guard must automatically and instantly return to the covering position.
JACKS
When working with jacks, you must consider the following.
* Use a device that stops jacks from jacking up too high.
* Never use jacks to support a lifted load. Once the load has been lifted, it
must be blocked up immediately.
* The manufacturer's rated capacity must be marked legibly.
* Use a positive stop to prevent over-travel.
* Block or crib the base of the jack when it is necessary to provide a firm
foundation.
* A wood block must be placed between the cap and the load of a jack when
there is a possibility that the metal cap of the jack will slip.
* Inspect jacks before each use and lubricate regularly. If a jack is subjected
to an abnormal load or shock, it should be examined thoroughly to make sure
it has not been damaged.
* Tag out-of-order jacks.
* Fill hydraulic jacks exposed to freezing temperatures with an adequate
antifreeze liquid.
Lesson Summary
This lesson contained information and instruction about tool safety. By
completing this lesson, you should have the knowledge to discuss the following
topics. Take a moment to see if you can do the following:
• Recognize tool hazards and apply the control hierarchy principles
• Identify and demonstrate safe practices for using hand and power tools
• Control a variety of power-operated tools effectively and safely
• Practice safety measures using these specific tools: portable circular
saws, portable drills, sanders, cordless power tools, woodworking tools,
and jacks
Welding and Cutting
Introduction
Because more than 500,000 workers in various industries are involved in welding and
cutting activities that pose a unique combination of safety and health risks, the level
of risk for fatal injury is moderately high. The actual count is more than four deaths
per thousand workers over a working lifetime. The good news is that a considerable
amount is known about control technology to reduce risk.
Welding is the most common method of joining metals in industry today. When
welded, two pieces of similar metals are fused (melted) together.
General hazards of welding include impact, penetration, harmful dust, smoke, fumes,
heat and light radiation. Proper personal protective equipment can protect you from
these hazards.
An estimated 562,000 employees are at risk for exposure to chemical and physical
hazards of welding and cutting.
In a typical year:
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Fifty-eight deaths from welding and cutting incidents, including explosions,
electrocutions, asphyxiation, falls and crushing injuries occur.
In the construction industry, welders flash (burn to the eyes) accounts for
5.6% of all construction eye injuries.
Welders represent 21% of the workers compensation claims for eye injuries.
OSHA's current standard for welding and cutting in construction is based on the 1967
American National Standards Institute (ANSI) standard Z49.1.
Lesson Overview
This lesson describes the history of welding and how welding fires start. Also covered
are the health hazards in this industry and the various safety precautions available.
Finally, this lesson describes what measures should be undertaken to assure proper
ventilation in areas where welding is being done. Upon completing this lesson, you
will be able to:
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Describe the three most frequently cited OSHA violations related to welding
Define the general welding hazards that PPE should reduce or eliminate
Describe ventilation methods used in welding and cutting work
Describe general precautions for assuring safe handling of oxyfuel welding
equipment
Differentiate between plasma arc welding, air carbon arc welding, and gas
shielded arc welding
Describe the five variables that can account for the amount of metal fumes and
gases and risk to which a welder is exposed
Why Learn This Lesson?
The lesson is designed to help the learner understand the importance of good safety
practices while working with and around welding and cutting operations.
The learner will review the hazards associated with welding and cutting operations
and the control measures to help reduce or eliminate these hazards. This information
should help the leaner recognize hazardous practices and participate in their control.
Topic 1: Welding Health Hazards
This topic introduces the numerous health hazards associated with exposure to
fumes, gases, and ionizing radiation formed or released during welding, cutting, and
brazing. These risks vary, depending upon the type of welding materials and welding
surfaces, but include heavy metal poisoning, lung cancer, metal fume fever, flash
burns, and others.
It also introduces the health hazards found in welding and cutting operations. Upon
completing this topic, you will be able to:
• Define the three primary elements in welding operations that cause fires
• Describe the three most frequently cited OSHA violations related to welding
• Explain the primary control measures to prevent welding fires
History
Bronze Age
If we define welding in its broadest sense as the achievement of a metallic bond, then
we can find examples in the Bronze Age city of Ur around 3,000 B.C. when swords
were joined by hammering and jewelry produced by hard soldering. However, it took
nearly 5,000 years for welding to become accepted as a suitable industrial process.
Iron Age
During the Iron Age, forge welding came into favor. By applying pressure and heat
two metals could be fused together (blacksmith welding), although a fully fused joint
could not be guaranteed; success depended on the operator's skill and experience.
1800s
During the 19th century the use of cast iron and steel for structural and mechanical
engineering increased. Cast iron ships such as the S.S. Great Britain built by Brunel in
1845 showed the extent of construction until large-scale steel production superseded
cast iron. Problems with riveting, such as weight and overlap, demanded a more
improved method of joining.
The basic principles of modern welding processes were discovered in 1724 (pressure
welding), 1820s (electric arc), and 1856 (resistance butt).
1900s
In the early 1900s the struggle began between riveting and welding, since the main
advantages of welding were its improvement in structural design and savings in
weight and cost/time. During the 1930s, welding was applied to the construction of
German pocket battleships to keep the weight within the treaty limit of 10,000 tons.
World War II forced many manufacturers to use the developing processes to increase
productivity and reduce costs; this in turn accelerated welding technology to such an
extent that welding is now regarded as a separate industry.
Welding Fires
0ne of the worst factory fires in history was started by sparks from a portable welding
outfit, which ignited liquid in a conveyor drip pan. The French liner Normandie was
being refitted to carry troops during World War II when welding sparks fell into waste
wood and excelsior, causing the fire that destroyed the ship. An aircraft carrier fire in
the Brooklyn Navy Yard in 1960 started when welding sparks and slag fell into spilled
motor fuel.
In each case, there either was inadequate protection or no protection of the
flammable material from flame and sparks. The ships were steel but were filled with
flammable material. The factory was steel, concrete, and glass, but contained
flammable fixtures, stock, and process material. Practically anything can burn and be
damaged if it gets hot enough. On any construction site, there's plenty of oil, grease,
and other combustible material such as lumber and scrap. How Welding Fires Start
Fires from welding operations are started by sparks, hot slag, and flame from the
torch. Sparks often drop or are carried long distances by the wind. Slag falls on
surfaces or materials below and a welding torch flame can ignite many substances
within a radius of several feet.
Workers must become familiar with the standard safety rules for welding so they can
spot, report, and help eliminate any problems.
Hierarchy of Controls
Reducing the risks associated with construction work is very important. To meet this
goal, there is a hierarchy or preferred order of control. These controls are not
mutually exclusive. There may be occasions when more than one control must be
used to reduce a risk. However, prevention would be best served by implementing
your hierarchy or control methodology before you start any construction operation.
The preferred order is presented in the graphic.
Engineering Controls
Engineering controls, which attempt to eliminate hazards, do not necessarily require
an engineer to design them. Engineering controls can be very simple. The work
environment and the job itself should be designed to eliminate or reduce exposure to
hazards based on the following principles:
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If feasible, design the job site, equipment, or process to remove the hazard or
substitute something that is not hazardous or is less hazardous.
If removal is not feasible, enclose the hazard to prevent exposure in normal
operations.
Where complete enclosure is not feasible, establish barriers to reduce exposure
to the hazard in normal operations.
Administrative Controls
Administrative controls are normally used in conjunction with other controls that more
directly prevent or control exposure to hazards. They include lengthened rest breaks,
additional relief workers, exercise breaks to vary body motions, and rotating workers
through different jobs to reduce stress or repetitive motions on one part of the body.
Administrative controls also includes introducing work practices that reduce the risk,
by means including the following:
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Limiting the amount of time a person is exposed to a particular hazard
Implementing and documenting safe working procedures for all hazardous
tasks
Training and instructing all personnel
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Identifying hazards prior to work commencing
Personal Protective Equipment
The last method of control is the use of PPE and it should only be considered
When other control measures are not practicable or to increase a person's protection
as an additional measure. PPE includes:
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Hard Hats
Eye Protection
Fall-arrest harnesses and lanyards
Foot Protection
Hand Protection
Respirators
Hearing protection
Administrative and Engineering controls can be utilized to eliminate welding and
cutting hazards prior to the beginning of operations. Personal protective equipment
(PPE) as a protection device is your last line of defense and this protects you from
welding and cutting hazards.
Training
The employer should make use of the safety and health training programs the
Secretary provides. The attached checklist provides a summary of what training must
cover.
OSHA Citations
What are the most frequently cited serious welding violations?
1. Arc welding cables improperly spliced or in need of repair (electric shock
hazard)
2. Inadequate ventilation while welding within a confined space (explosion or
respiratory hazard)
3. Regulators and gauges on compressed gas cylinders not in proper working
order (danger of uncontrolled release of compressed gases)
What effective measures can be used to control these hazards?
1. Inspect welding cables daily before use and repair or replace, if needed. All
cable splicing must maintain the insulated protection with no exposed metal
parts. Cables needing repair must not be used until they are in safe,
serviceable condition.
2. Confined spaces must be adequately ventilated while welding is underway to
control hazardous welding fumes. Sections 1926.353 and 1926.350 provide
additional specific criteria.
3. Regulators and gauges should be inspected daily before welding or cutting
begins. Cylinders with defective regulators or gauges should not be used until
the defective equipment is replaced or repaired. Section 1926.350 lists specific
criteria.
Topic Summary
Please take a moment to review these major points before you continue with the next
topic.
• Welding fires usually can be attributed to inadequate protection or no
protection of the flammable material from flame and sparks.
• Fires from welding operations are started by sparks, hot slag, and flame from
the torch.
• Arc welding cables improperly spliced or in need of repair are an electric shock
hazard.
• Inadequate ventilation while welding within a confined space is an explosion or
respiratory hazard.
• Regulators and gauges on compressed gas cylinders not in proper working
order are a danger from the uncontrolled release of compressed gases.
• Effective measures to control welding hazards include: --fix audio too.
• Inspect welding cables daily before use and repair or replace, if needed. All
cable splicing must maintain the insulated protection with no exposed metal
parts. Cables needing repair must not be used until they are in safe serviceable
condition.
• Confined spaces must be adequately ventilated while welding is underway to
control hazardous welding fumes.
• Follow the OSHA standard that mandates that combustible materials must be
located 35 feet from the worksite. Until they can be moved to that safe
distance, cover them with a flameproof material.
Topic 2: Precautions for General Safety, Fire and PPE
This topic contains information on general safety measures, fire safety and protection,
and PPE for the welding industry.
Upon
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completing this topic, you will be able to:
Discuss the general safety practices for welding and cutting
Define the general welding hazards that PPE should reduce or eliminate
List PPE devices that are recommending for use in welding
Describe fire safety precautions for this work
General Safety Precautions
To prevent injury to personnel, exercise extreme caution when using any type of
welding equipment. Injury can result from fire, explosions, electric shock, or harmful
agents. Workers who weld or cut metals must strictly observe both the general and
specific safety precautions in this lesson.
General precautions to prevent welding incidents include:
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Do not permit unauthorized persons to use welding or cutting equipment.
Do not weld in a building with wooden floors, unless the floors are protected
from hot metal by fire-resistant fabric and/or other fireproof material. Be sure
that hot sparks or hot metal will not fall on the operator or on any welding
equipment components.
Remove all flammable material, such as cotton, oil, gasoline, etc. from the
vicinity of welding.
Before welding or cutting, warn those in close proximity to wear proper clothing
or goggles.
Remove any assembled parts from the component being welded that may
become warped or damaged by the welding process.
Remove hot rejected electrode stubs, steel scrap, or tools from the floor or
near the welding equipment to prevent accidents and/or fires.
Keep a suitable fire extinguisher nearby at all times. Ensure the fire
extinguisher is in operable condition.
Mark all hot metal after welding operations are completed. Soapstone is
commonly used for this purpose.
First aid guidelines include:
First aid equipment must be available at all times. On every shift of welding
operations, there should be personnel present who are trained to render first
aid.
All injuries should be reported as soon as possible for medical attention. First
aid should be rendered until medical attention can be provided.
Fire Hazards and Safety
Fire prevention is the responsibility of welders, cutters, and supervisors. Portable
cutting and welding equipment and welding activities done in areas not specifically
designated for such work cause approximately six percent of industrial plant fires.
Details of basic precautions to be taken for fire prevention during welding or cutting
are found in the Standard for Fire Prevention in Use of Cutting and Welding
Processes, National Fire Protection Association Standard 51B, 1962.
Fire Safety
Fire safety is important consideration for workers who perform welding and cutting
operations.
Some of the basic safety precautions for fire prevention in welding or cutting work are
listed here:
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Sparks and molten spatter formed during welding and cutting operations can
sometimes fly considerable distances. Sparks also have fallen through cracks,
pipe holes, or other small openings in floors and partitions, starting fires in
areas that temporarily may go unnoticed. For these reasons, welding or cutting
should not be performed near flammable materials unless every precaution is
taken to prevent ignition.
Hot pieces of base metal may come in contact with combustible materials and
start fires. Fires and explosions also have been caused when heat is
transmitted through walls of containers to flammable atmospheres or to
combustibles within containers. Anything combustible or flammable is
susceptible to ignition by cutting and welding.
No welding, cutting, or heating should be done where the application of
flammable paints, the presence of other flammable compounds, or heavy dust
concentrations creates a hazard.
When welding, cutting, or heating is performed on walls, floors, and ceilings,
the same precautions must be taken on the opposite side as are taken on the
side on which the welding is being performed, since direct penetration of
sparks or heat transfer may introduce a fire hazard to an adjacent area.
To eliminate possible fire in enclosed spaces from gas escaping through leaking
or improperly closed torch valves, positively shut off the gas supply to the
torch outside the enclosed space whenever the torch is not to be used or is left
unattended for a substantial period of time, such as during the lunch period.
Hazard Removal
• When welding or cutting parts of vehicles, the oil pan, gasoline tank, and other
parts of the vehicle considered fire hazards must be removed or effectively
shielded from sparks, slag, and molten metal.
• Whenever possible, remove flammable materials attached to or near
equipment requiring welding, brazing, or cutting. If removal is not practical,
use a suitable shield of heat-resistant material to protect the flammable
material. Fire extinguishing equipment, for any type of fire that may be
encountered, must be present.
• When practical, move objects to be welded, cut, or heated to a designated safe
location; if these objects cannot readily be moved, all movable fire hazards in
the vicinity must be taken to a safe place or otherwise protected. Positive
means must be taken to confine the heat, sparks, and slag, and to protect the
immovable fire hazards from them.
Fire Equipment and Personnel
• Suitable fire extinguishing equipment must be immediately available in the
work area and must be maintained in a state or readiness for instant use.
• When normal fire prevention precautions are not sufficient, additional
personnel must be assigned to guard against fire while the actual welding,
cutting, or heating operation is being performed and for a sufficient period of
time after completing work to ensure that no possibility of fire exists.
• Such personnel must be instructed on the specific anticipated fire hazards and
how firefighting equipment provided is to be used.
• Equipment Removal
• The torch and hose must be removed from the confined space overnight and at
the change of shifts.
• Open-end fuel gas and oxygen hoses must be immediately removed from
enclosed spaces when disconnected from the torch or other gas-consuming
device.
• Drums, Pails, and Containers
• Drums, pails, and other containers that contain or have contained flammable
liquids must be kept closed except when the contents are being removed or
transferred. Empty containers must be moved to a safe area apart from hot
work operations or open flames.
• Before welding, cutting, or heating begins on drums, containers, or hollow
structures that have contained toxic or flammable substances, either fill the
containers with water or thoroughly clean, ventilate, and test them for such
substances.
• Before applying heat to a drum, container, or hollow structure, provide a vent
or opening for the release of any built-up pressure during the application of
heat.
Personal Protective Equipment
Protective clothing and equipment must be worn during all welding operations
because the electric arc is a very powerful source of light, including visible,
ultraviolet, and infrared light.
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•
During all oxyacetylene welding and cutting processes, operators must use
safety goggles to protect the eyes from heat, glare, and flying fragments of hot
metals.
During all electric welding processes, operators must use safety goggles and a
hand shield or helmet equipped with a suitable filter glass to protect against
the intense ultraviolet and infrared rays.
Helmets and Shields
Welding arcs are intensely brilliant lights. They contain a proportion of ultraviolet light
that may cause eye damage. For this reason, the arc should never be viewed with the
naked eye within a distance of 50 feet (15.2 meters). The brilliance, exact spectrum,
and the danger of the light are determined by the welding process, the metals in the
arc, the arc atmosphere, the length of the arc, and the welding current.
Operators, fitters, and those working nearby need protection against arc radiation.
The intensity of the light from the arc increases with increasing current and arc
voltage. Arc radiation, like all light radiation, decreases as the distance from the light
increases.
Processes that produce smoke surrounding the arc have a less bright arc since the
smoke acts as a filter. The spectrum of the welding arc is similar to that of the sun,
and exposure of the skin and eyes to the arc is the same as exposure to the sun.
Click each picture to learn more.
Helmets
Being closest, the welder needs a helmet to protect his eyes and face from harmful
light and particles of hot metal. The welding helmet generally is constructed of a
pressed fiber-insulating material. It has an adjustable headband that makes it usable
by persons with different head sizes. To minimize reflection and glare produced by
the intense light, the helmet is dull black in color. It fits over the head and can be
swung upward when not welding. The chief advantage of the helmet is that it leaves
both hands free, making it possible to hold the work and weld at the same time.
Shield
The hand-held shield provides the same protection as the helmet, but is held in
position by the handle. An observer or a person who welds for a short period of time
frequently uses this type of shield.
Do not weld with cracked or defective shields because penetrating rays from the arc
may cause serious burns.
Lens Holders
The protective welding helmet has lens holders that grip the cover glass and the filter
glass or plate. Standard size for the filter plate is 2 x 4 1/4 inches. In some helmets,
lens holders open or flip upward.
Lenses
• Lenses are designed to prevent flash burns and eye damage by absorbing the
infrared and ultraviolet rays produced by the arc. The filter glasses or plates
come in various optical densities to filter out various light intensities,
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depending on the welding process, type of base metal, and the welding
current.
The color of the lens, usually green, blue, or brown, is an added protection
against the intensity of white light or glare.
Colored lenses make it possible to see the metal clearly and weld.
[Insert Nice to Know Button] [Insert popup Table 2-1 This table lists the proper
filter shades to be used.
A magnifier lens placed behind the filter glass sometimes is used to provide
clear vision.
A cover plate should be placed outside the filter glass to protect it from weld
spatter.
The filter glass must be tempered to prevent breaking if hit by flying weld
spatter.
Filter glasses must be marked showing the manufacturer, the shade number,
and the letter H indicating it has been treated for impact resistance.
Gas metal-arc (MIG) welding requires darker filter lenses than shielded metalarc (stick) welding. The intensity of the ultraviolet radiation emitted during gas
metal-arc welding ranges from 5 to 30 times brighter than welding with
covered electrodes.
Gas metal arc (MIG) welding requires darker filter lenses than shielded metal
arc (stick) welding. The intensity of the ultraviolet radiation emitted during gas
metal arc welding ranges from 5 to 30 times brighter than welding with
covered electrodes.
Colored Glass Plates
Be sure that the colored glass plates are the proper shade for arc welding. Protect the
colored glass plate from molten metal spatter by using a cover glass. Replace the
cover glass when damaged or spotted by molten metal spatter.
Lens Shades for Welding and Cutting
Welding or Cutting Electrode Size
Operation
Metal Thickness or
Welding Current
Torch soldering
Torch brazing
Oxygen cutting
Light
Medium
Heavy
Gas welding
Light
Medium
Under 1 in (25 mm)
1-6 in (25-150 mm)
Over 6 in (150 mm)
Under 1/8 in (3 mm)
1/8-1/2 in (3-12 mm)
Filter Shade
Number
2
3 or 4
3 or 4
4 or 5
5 or 6
4 or 5
5 or 6
Heavy
Over 1/2 in (12 mm)
6 or 8
Shielded metal arc
Under 5/32 in (4 mm)
Welding (stick)
5/32-1/4 in (4-6.4 mm)
Electrodes
Over 1/4 in (6.4 mm)
Gas metal arc welding (MIG)
Nonferrous base metal
Ferrous base metal
Gas tungsten arc welding (TIG) All
Atomic hydrogen welding
Carbon arc welding
All
Plasma arc welding
All
10
12
14
All
All
11
12
12
All
Carbon arc air gouging
Light
Heavy
Plasma arc cutting
Light
Under 300 Amp
Medium
300-400 Amp
Heavy
Over 400 Amp
12
12
12
12
12
14
9
12
14
Safety Goggles
During all electric welding processes, operators must wear safety goggles to protect
their eyes from weld spatter that occasionally gets inside the helmet. These clear
goggles also protect the eyes from slag particles when chipping and hot sparks when
grinding. Tinted safety glasses with side shields are recommended, especially when
welders are chipping or grinding. Those working around welders should also wear
tinted safety glasses with side shields.
The OSHA policy regarding the wearing of contact lens in industry is consistent with
the attached position set forth by the National Society for the Prevention of Blindness
(Secretariat for the ANSI Z87.1 - Committee).
If properly protected in accordance with the OSHA Standards applicable to eye
protection (ANSI Z87.1), the use of contact lenses is acceptable during the welding
operation. The exception to this would be where the welding process may produce
gas or vapors that could be harmful to employees wearing contact lenses.
Protective Clothing
Personnel exposed to the hazards created by welding, cutting, or brazing operations
must be protected by personal protective equipment in accordance with OSHA
standards. Welders should wear work or shop clothes without openings or gaps, to
prevent arc rays from contacting the skin. Those working close to arc welding also
should wear protective clothing. The appropriate protective clothing required for any
welding operation will vary with the size, nature, and location of the work to be
performed. Clothing always should be kept dry, including gloves.
Woolen clothing should be worn instead of cotton, since wool is not easily burned or
damaged by weld spatter and helps protect the welder from changes in temperature.
Cotton clothing, if used, should be chemically treated to reduce its combustibility. All
other clothing, such as jumpers or overalls, should be reasonably free from oil or
grease.
Review this partial list of recommendations for clothing used in welding and cutting:
• Flameproof aprons or jackets made of leather, fire resistant material, or other
suitable material should be worn for protection against spatter of molten metal,
radiated heat, and sparks.
• Capes or shoulder covers made of leather or other suitable materials should be
worn during overhead welding or cutting operations.
• Leather skull caps may be worn under helmets to prevent head burns. Sparks
may lodge in rolled-up sleeves, pockets of clothing, or cuffs of overalls and
trousers. Therefore, sleeves and collars should be kept buttoned and pockets
should be eliminated from the front of overalls and aprons. Trousers and
overalls should not be turned up on the outside. For heavy work, fire-resistant
leggings, high boots, or other equivalent means should be used. In production
work, a sheet metal screen in front of the worker's legs can provide further
protection against sparks and molten metal in cutting operations.
• Flameproof gauntlet gloves, preferably of leather, should be worn to protect
the hands and arms from rays of the arc, molten metal spatter, sparks, and hot
metal. Leather gloves should be of sufficient thickness so that they will not
shrivel from the heat, burn through, or wear out quickly. Leather gloves should
not be used to pick up hot items since this causes the leather to become stiff
and crack. Do not allow oil or grease to come in contact with gloves because
this reduces their flame resistance and causes them to be readily ignited or
charred.
Respiratory Protection
Construction employees can be exposed to a variety of respiratory hazards that
include vapors, fumes, and particles. Welding operations release gases and fumes
filled with metals and other toxins. The solvents used in many operations give off
harmful vapors. Also, particles released as dust are generated during grinding
operations and placement of insulation materials such as fiberglass.
What types of hazards require respiratory protection?
Gaseous Contaminants
Gaseous contaminants add harmful, invisible gases or vapors to the air. Chemicals
can be gases at room temperature but become solids or liquids at low temperatures
or high pressure. Carbon dioxide is a gas at room temperature. At low temperatures
it becomes solid dry ice. Under pressure in cylinders it is a liquid. Vapors are like
gases except that they are formed by the evaporation of liquid substances. Examples
include acetone and trichloroethylene, which ordinarily exist as liquids.
Particulate Contaminants
Particulate contaminants are tiny particles or droplets of hazardous material in the
air. They are classified as dusts, mists, and fumes. Dusts are solid and can be created
by grinding, crushing, sanding, or mixing operations. Examples include sand and
plaster dust. Mists are liquid droplets and are given off by the spraying or mixing of
liquids. Fumes are very small metal particles given off as metals are heated. Welding,
brazing, soldering, and other molten metal processes produce fumes.
Gaseous and particulate contaminants often occur together. Spray painting operations
produce particulates in the form of paint mists and solvent vapors that are gaseous
contaminants.
Atmospheres Immediately Dangerous to Life or Health (IDLH)
IDLH are conditions that can result in severe injury or death in a short time or have
serious delayed effects. Carbon monoxide or hydrogen sulfide exposures can result in
death even within a short period. Radioactive materials or cancer-causing chemicals
can have serious delayed effects.
Oxygen-Deficient Atmospheres
Oxygen-deficient atmospheres are areas that do not have a safe level of oxygen in
the air. These areas are classified as Immediately Dangerous to Life or Health (IDLH).
However, not all IDLH are oxygen-deficient atmospheres (e.g., radioactive materials
or cancer-causing chemicals). Exposure to these atmospheres can cause brain
damage and death. Low levels of oxygen are frequently found in confined and poorly
ventilated spaces such as silos and storage tanks. Oxygen can be used up by
chemical reactions or moved away by other gases when leaks occur. Fire is a common
chemical reaction that uses up oxygen.
Protective Equipment
In confined spaces where there is exposure to sharp or heavy falling objects or a
hazard of bumping, hard hats or head protectors must be used. For welding and
cutting overhead or in confined spaces, steel-toed boots and ear protection also must
be used.
When welding in any area:
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The operation should be adequately screened to protect nearby workers or
passers-by from the glare of welding.
Screens should be arranged to prevent serious restriction of ventilation.
Screens should be mounted so they are about two feet above the floor, unless
the work is performed at such a low level that the screen must be extended
closer to the floor to protect adjacent workers from the glare of welding
The height of the screen is normally 6 feet but may be higher depending upon
the situation.
The screen and surrounding areas must be painted with special paints that
absorb ultraviolet radiation yet do not create high contrast between the bright
and dark areas. Light pastel colors of a zinc or titanium dioxide base paint are
recommended. Black paint should not be used.
When welding must be performed in a space entirely screened on all sides, the
screens must be arranged so that no serious restriction of ventilation exists.
Topic Summary
Please take a moment to review these key points before you continue with the next
topic.
• Do not permit unauthorized persons to use welding or cutting equipment.
• Do not weld in a building with wooden floors, unless the floors are protected
from hot metal by fire-resistant fabric and/or other fireproof material. Be sure
that hot sparks or hot metal will not fall on the operator or on any welding
equipment components.
• Remove all flammable material, such as cotton, oil, gasoline, etc. from the
vicinity of welding.
• Before welding or cutting, warn those in close proximity to wear proper clothing
or goggles.
• Remove any assembled parts from the component being welded that may
become warped or damaged by the welding process.
• Remove hot rejected electrode stubs, steel scrap, or tools from the floor or
near the welding equipment to prevent accidents and/or fires.
• Keep a suitable fire extinguisher nearby at all times. Ensure the fire
extinguisher is in operable condition.
• Mark all hot metal after welding operations are completed.
• The welding arc should never be viewed with the naked eye within a distance
of 50 feet.
• Operators, fitters, and those working nearby need protection against arc
radiation. The intensity of the light from the arc increases with increasing
current and arc voltage.
• The chief advantage of the helmet is that it leaves both hands free, making it
possible to hold the work and weld at the same time.
• Protective clothing and other PPE should be used by anyone near the welding
site.
•
Clothing worn by those in the welding area should follow clothing guidelines to
avoid burns, flammable substances, and flying or dropping debris that can
ignite the material.
Topic 3: Health Protection and Ventilation
Ventilation refers to changing room air as often as necessary to prevent welders and
other workers from breathing high levels of airborne contaminants. Ventilation
provides adequate breathing air that is required for all welding, cutting, brazing, and
related operations. Proper ventilation can be obtained either naturally or
mechanically. Adequate ventilation depends on:
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Volume and configuration of the space where welding operations occur
Number and type of operations generating contaminants
Natural airflow rate where operations are taking place
Locations of the welders' and other workers' breathing zones in relation to the
contaminants or sources of room air.
General Information
Monitoring instruments should be used to detect harmful atmospheres. Where it is
impossible to provide adequate ventilation, air-supplied respirators or hose masks
approved for this purpose must be used. All welding and thermal cutting operations in
confined spaces must be adequately ventilated to prevent the accumulation of toxic
materials, combustible gases, or possible oxygen deficiency. In these situations,
lookouts must be used on the outside of the confined space to ensure the safety of
those working within.
Established requirements for arc and gas welding and cutting mandate:
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The amount of contamination to which welders may be exposed
Dimensions of the area where the welding process occurs especially the ceiling
height
Number of welders in the room
Possible development of hazardous fumes, gases, or dust from the metals
involved
Location of welder's breathing zone with respect to rising plume of fumes
In specific cases, other factors involved mandate that respirator protective devices
(ventilation) should be provided to meet the equivalent requirements. They include:
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Atmospheric conditions
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Generated heat
Presence of volatile solvents
In all cases, the required health protection, ventilation standards, and standard
operating procedures for new and old welding operations should be coordinated and
cleared through the safety inspector and the industrial hygienist responsible for the
safety and health aspects of the work area.
What is a fume plume?
The fume plume is the clearly visible column of fume which rises directly from the
spot of welding or cutting. Welders and cutters should take precautions to avoid
breathing this area directly. Ventilation can direct the plume away from the face.
Fume removal is most effective when the air flow is directed across the face of the
welder, rather than from behind.
Respiratory Protective Equipment
Individual respiratory protective equipment must be well maintained. Only respiratory
protective equipment approved by the U.S. Bureau of Mines, National Institute of
Occupational Safety and Health, or other government-approved testing agency must
be used. Guidance for selection, care, and maintenance of respiratory protective
equipment is given in Practices for Respiratory Protection, American National
Standard Institute Standard 788.2 and TB MED 223.
Precautionary Labels
A number of potentially hazardous materials are used in flux coatings, coverings, and
filler metals. These materials, when used in welding and cutting operations, become
hazardous to the welder as they are released into the atmosphere. These include but
are not limited to fluorine compounds, zinc, lead, beryllium, cadmium, and mercury.
The suppliers of welding materials must determine the hazard, if any, associated with
using their materials in welding, cutting, etc.
All filler metals and fusible granular materials must carry the following notice, as a
minimum, on tags, boxes, or other containers:
CAUTION
Welding may produce fumes and gases hazardous to health. Avoid breathing these
fumes and gases. Use adequate ventilation. See American National Standards
Institute Standard Z49.1-1973, Safety in Welding and Cutting published by the
American Welding Society.
Brazing (welding) filler metals containing cadmium in significant amounts must carry
the following notice on tags, boxes, or other containers:
WARNING
CONTAINS CADMIUM - POISONOUS FUMES MAY BE FORMED ON HEATING
Do not breathe fumes. Use only with adequate ventilation, such as fume collectors,
exhaust ventilators, or air-supplied respirators. See American National Standards
Institute Standard Z49.1-1973. If chest pain, cough, or fever develops after use, call
physician immediately.
Brazing and gas welding fluxes containing fluorine compounds must have a
cautionary wording. One such wording recommended by the American Welding
Society for brazing and gas welding fluxes reads:
CAUTION
CONTAINS FLUORIDES
This flux, when heated, gives off fumes that may irritate eyes, nose, and throat.
Avoid fumes - use only in well-ventilated spaces.
Avoid contact of flux with eyes or skin.
Do not take internally.
Concentration of Toxic Substances
Local exhaust or general ventilating systems must be provided and arranged to keep
the amount of toxic frees, gas, or dusts below the acceptable concentrations as set by
the American National Standard Institute Standard 7.37; the latest Threshold Limit
Values (TLV) of the American Conference of Governmental Industrial Hygienists; or
the exposure limits as established by OSHA. Compliance must be determined by
sampling the atmosphere. Samples collected must reflect the exposure of the persons
involved. When a helmet is worn, the samples must be collected under the helmet.
NOTE: Where welding operations are incidental to general operations, it is
considered good practice to apply local exhaust ventilation to prevent
contamination of the general work area.
Natural Ventilation
Natural ventilation is considered sufficient for welding and brazing operations if the
present work area meets these requirements:
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Provide more than 10,000 square feet. of space per welder.
The ceiling height is more than 16 feet.
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Welding is not done in a confined space.
Welding space does not contain partitions, balconies, or structural barriers that
obstruct cross-ventilation.
If a specific operation does not fall within these guidelines, mechanical ventilation is
required.
Mechanical Ventilation
Mechanical ventilation must be provided when welding or cutting is done on metals
under the following conditions:
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In a space of less than 10,000 cubic feet per welder
In a room having a ceiling height of less than 16 feet
In confined spaces or where the welding space contains partitions, balconies, or
other structural barriers that significantly obstruct cross-ventilation
Ventilation must be at the minimum rate of 200 cubic feet per minute per welder,
except where local exhaust hoods or airline respirators approved by the U.S. Bureau
of Mines, National Institute of Occupational Safety and Health, or other governmentapproved testing agency, are used.
Welding booth equipped with mechanical ventilation sufficient for one welder.
Local Exhaust Ventilation
Mechanical local exhaust ventilation may be obtained by using hoods or fixed
enclosures:
Hoods: Freely movable hoods or ducts should be placed as near as practical to the
work being welded. These devices provide an airflow in the direction of the hood that
is sufficient to maintain a velocity of 100 linear feet/minute in the welding zone. This
table shows ventilation rates required to accomplish this control velocity using a
three-inch flanged suction opening.
Fixed enclosure:
• A fixed enclosure with a top and two or more sides surrounding the welding or
cutting operations must have a rate of airflow sufficient to maintain a velocity
away from the welder of not less than 100 linear feet/minute.
• Downdraft ventilation tables require 150 cubic feet per minute/square foot of
surface area. This rate of exhausted air must be uniform across the face of the
grille.
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A low-volume, high-density fume exhaust device attached to the welding gun
collects the fumes as close as possible to the point of origin or at the arc. This
method of fume exhaust has become quite popular for semiautomatic
processes, particularly the flux-cored arc welding process.
Smoke exhaust systems incorporated in semiautomatic guns provide the most
economical exhaust system. Because they exhaust much less air, they
eliminate the need for massive air makeup units to provide heated or cooled air
to replace the air exhausted.
Local ventilation should have a rate of airflow sufficient to maintain a velocity
away from the welder of not less than 100 feet per minute. Air velocity is
measured using a velometer or airflow meter. These two systems can be
extremely difficult to use when welding other than small weldments. Downdraft
welding work tables, popular in Europe, are used to a limited degree in North
America.
Required Exhaust Ventilation
Welding zone
(Inches from arc or torch)
4-6
6-8
8-10
10-12
Minimum airflow
(Cubic feet/minute)
150
275
425
600
Duct diameter
(In inches)
3
3 1/2
4 1/2
6 1/2
Ventilation in Confined Spaces
A confined space means a relatively small or restricted workspace such as a tank,
boiler, pressure vessel, or small compartment of a ship or tank. Ventilation is a
prerequisite to work in confined spaces. To prevent the accumulation of toxic
materials or possible oxygen deficiency in the welder, helpers, and other personnel in
the immediate vicinity, all welding and cutting operations require ventilation.
In circumstances where it is impossible to provide adequate ventilation in a confined
area, airline respirators or hose masks approved by the National Institute of
Occupational Safety and Health should be used. The air should meet the OSHA
standards.
In areas immediately hazardous to life, hose masks with blowers or self-contained
breathing equipment should be used. All breathing equipment should be approved by
the National Institute of Occupational Safety and Health (NIOSH).
Where welding operations are carried on in confined spaces and where welders and
helpers are provided with hose masks, hose masks with blowers, or self-contained
breathing equipment, a worker must be stationed outside such confined spaces to
ensure the safety of those working within.
NOTE: Oxygen must never be used for ventilation.
In addition to ventilation requirements, other welding safety requirements are
involved in confined space work. Click here to see the general requirements.
Confined Space Welding Safety Requirements
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When welding or cutting in any confined space, leave the gas cylinders and
welding machines on the outside.
Before operations begin, securely block heavy portable equipment mounted on
wheels to prevent accidental movement.
Where a welder must enter a confined space through a manhole or other
opening, provide a means for quickly removing him in case of an emergency.
Station an attendant with a preplanned rescue procedure outside to observe
the welder at all times. The attendant should be capable of putting rescue
operations into effect.
Safety harnesses and lifelines used for rescue operations must be attached to
the welder's body so that he cannot be jammed in a small exit opening.
When arc welding is suspended for any substantial period of time, such as
during lunch or overnight, remove all electrodes from the holders and carefully
locate the holders so that accidental contact cannot occur.
Disconnect welding machines from the power source.
To eliminate the possibility of gas escaping through leaks or improperly closed valves
when gas welding or cutting:
• Close gas and oxygen supply valves
• Release regulators
• Bleed gas and oxygen lines
• Shut off torch valves when equipment is not used for a substantial period of
time
• Remove torch and hose from confined space, where practical
• After completing welding operations, welder must mark hot metal or provide
some other means of warning other workers
Protection From Various Elements
Fluorine Compounds
In confined spaces, welding or cutting involving fluxes, coverings, or other materials
with fluorine compounds must meet the requirements for confined space ventilation.
A fluorine compound is one that contains fluorine as an element in chemical
combination, not as a free gas.
Individual circumstances determine the need for local exhaust ventilation or airline
respirators for welding or cutting in other than confined spaces. However, experience
has shown that such protection is desirable for fixed-location production welding and
for all production welding on stainless steels. When air samples taken at the welding
location indicate that the fluorides liberated are below the maximum allowable
concentration, such protection is not necessary.
Zinc
In confined spaces, welding or cutting involving zinc-bearing filler metals or metals
coated with zinc-bearing materials must be done according to the requirements for
ventilation in confined spaces.
Indoors, welding or cutting involving zinc-bearing metals or filler metals coated with
zinc-bearing materials must be done according to the requirements for local exhaust
ventilation.
Lead
In confined spaces, welding involving lead-based metals (erroneously called leadburning) must be according to the requirements for ventilation in confined spaces. In
confined spaces or indoors, welding or cutting involving metals containing lead or
metals coated with lead-bearing materials, including paint, must be done using local
exhaust ventilation or airline respirators.
Outdoors, such operations must be done using respirator protective equipment
approved by the National Institute of Occupational Safety and Health. In all cases,
workers in the immediate vicinity of the cutting or welding operation must be
protected as necessary by local exhaust ventilation or airline respirators.
Indoors, welding involving lead-based metals must be done in accordance with the
requirements for local exhaust ventilation.
Beryllium
Welding or cutting indoors, outdoors, or in confined spaces involving berylliumbearing material or filler metals should be done using local exhaust ventilation and
airline respirators. This must be performed without exception unless atmospheric
tests under the most adverse conditions have established that the workers' exposure
is within the acceptable concentrations of the latest Threshold Limit Values (TLV) of
the American Conference of Governmental Industrial Hygienists or the exposure limits
established by OSHA. In all cases, workers in the immediate vicinity of the welding or
cutting operations must be protected as necessary by local exhaust ventilation or
airline respirators.
Cadmium
Welding or cutting indoors or in confined spaces involving cadmium-bearing or
cadmium-coated base metals will be done using local exhaust ventilation or airline
respirators. Outdoors, such operations must be done using respiratory protective
equipment such as fume respirators, approved by the National Institute of
Occupational Safety and Health.
Welding (brazing) involving cadmium-bearing filler metals must be done using
ventilation as prescribed in the requirements for local exhaust ventilation, and
ventilation in confined spaces, if the work is to be done in a confined space.
NOTE: Cadmium-free rods are available and can be used in most instances with
satisfactory results.
Mercury
Welding or cutting indoors or in a confined space involving metals coated with
mercury-bearing materials, including paint, must be done using local exhaust
ventilation or airline respirators. Outdoors, such operations should be done using
respiratory protective equipment approved by the National Institute of Occupational
Safety and Health.
Stainless Steels
Oxygen cutting, using either a chemical flux or iron powder, or gas-shielded arc
cutting of stainless steel should be done using mechanical ventilation adequate to
remove the fumes generated.
Topic Summary
Please take a moment to review these key points before you continue with the next
topic.
• Ventilation is done to prevent the accumulation of toxic materials, combustible
gases, or possible oxygen deficiency.
• Monitoring instruments should be used to detect harmful atmospheres.
• Where it is impossible to provide adequate ventilation, air-supplied respirators
or hose masks approved for this purpose must be used. I
• In these situations, lookouts must be used on the outside of the confined space
to ensure the safety of those working within the confined space
• Arc and gas welding and cutting requirements govern the amount of
contamination to which welders may be exposed:
• In all cases, the required health protection, ventilation standards, and standard
operating procedures for new and old welding operations should be coordinated
and cleared through the safety inspector and the industrial hygienist
responsible for the safety and health aspects of the work area.
• When a helmet is worn during welding, samples must be collected under the
helmet.
• Respiratory protective equipment must not be transferred from one individual
to another without being disinfected.
• The suppliers of welding materials must determine the hazard associated with
using their materials in welding, cutting, etc.
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Smoke exhaust systems incorporated in semiautomatic guns provide the most
economical exhaust system.
Mechanical ventilation must be provided when welding or cutting is done on
metals:
o In a space of less than 10,000 cubic feet per welder
o A ceiling height of less than 16 feet
o In confined spaces or where the welding space contains partitions,
balconies, or other structural barriers that significantly obstruct crossventilation
Topic 4: Safety Precautions In Oxyfuel Welding
This topic describes the general and specific safety precautions in oxyfuel welding and
the proper steps for lighting and extinguishing torches. The topic also describes the
proper use and storage of four types of cylinders and hazards and proper care of
hoses.
Upon completing this topic, you will be able to:
• Describe general precautions for assuring safe handling of oxyfuel welding
equipment
• Define the characteristics of the four gases that determine how they can be
used in welding
General Precautions
In oxygen cutting, a gas flame heats the metal and an oxygen jet does the cutting. In
addition to the safety information listed in previous topics of this lesson, when
engaging in oxyfuel welding these safety precautions must be observed:
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Do not experiment with torches or regulators in any way.
Do not use oxygen regulators with acetylene cylinders.
Do not use any lubricants on regulators or tanks.
Always use the proper tip or nozzle, and always operate it at the proper
pressure for the particular work involved. The correct information is available
on worksheets or tables supplied with the equipment.
When not in use, make sure the torch is not burning, release the regulators,
bleed the hoses, and tightly close the valves. Do not hang the torch with its
hose on the regulator or cylinder valves.
Do not light a torch with a match or hot metal, or in a confined space. The
explosive mixture of acetylene and oxygen might cause personal injury or
property damage when ignited. Use friction lighters or stationary pilot flames.
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When working in confined spaces, provide adequate ventilation to dissipate
explosive gases that may be generated. For ventilation standards, refer to the
requirements listed in the topic "Ventilation in Confined Spaces."
Keep a clear space between the cylinder and the work so the cylinder valves
can be reached easily and quickly.
Use cylinders in the order received. Store full and empty cylinders separately
and mark the empty ones with "MT."
Compressed gas cylinders owned by commercial companies should not be
painted regulation Army olive drab.
Never use cylinders for rollers, supports, or any purpose other than that for
which they are intended.
Always wear protective clothing suitable for welding or flame cutting.
Keep work area clean and free from hazardous materials. When flame cutting,
sparks can travel 30-40 feet (9-12 meters). Do not allow flare-cut sparks to hit
hoses, regulators, or cylinders.
Use oxygen and acetylene or other fuel gases with the appropriate torches only
for the purpose intended.
Treat regulators with respect. Do not use force to turn the valve handle.
Where should oxygen not be used and why?
Oxygen should not be used as a substitute for compressed air. It should not be used
in pneumatic tools, in oil preheating burners, to start internal combustion engines, to
blow out pipelines, to dust clothing or work, or to create pressure for ventilation or
similar applications. Oxygen should not be used as described due to the possibility of
a raging oxygen-fed fire occurring. Oxygen is not flammable, but vigorously supports
combustion. Oxygen can be absorbed by clothing. A slight spark can result in severe
burns.
Lighting and Extinguishing Torches
To Light a Torch
Always use the following sequence and technique for lighting a torch:
1. Open acetylene cylinder valve.
2. Open acetylene torch valve one-quarter turn.
3. Screw in acetylene regulator, adjusting valve handle to working pressure.
4. Turn off the acetylene torch valve. (This purges the acetylene line.)
5. Slowly open oxygen cylinder valve all the way.
6. Open oxygen torch valve one-quarter turn.
7. Screw in oxygen regulator screw to working pressure.
8. Turn off oxygen torch valve. (This purges the oxygen line.)
9. Open acetylene torch valve one-quarter turn and light with lighter.
10.Open oxygen torch valve one-quarter turn.
11.Adjust to neutral flame.
To Shut off a Torch
Always use the following sequence and technique for shutting off a torch:
1. Close acetylene torch valve first, then oxygen valve.
2. Close acetylene cylinder valve, then oxygen cylinder valve.
3. Open torch acetylene and oxygen valves to release pressure in the regulator
and hose.
4. Back off regulator adjusting valve handle until no spring tension is left.
5. Close torch valves.
6. Use mechanical exhaust at the point of welding when welding or cutting lead,
cadmium, chromium, manganese, brass, bronze, zinc, or galvanized steel.
7. Do not weld or flame cut containers that have held combustibles without taking
special precautions.
8. Do not weld or flame cut into sealed container or compartment without
providing vents and taking special precautions.
9. Do not weld or cut in a confined space without taking special precautions.
Acetylene Cylinders
Acetylene is a compound of carbon and hydrogen, produced by the reaction of water
and calcium carbide. It is a highly combustible fuel gas and great care should be
taken to keep sparks, flames, and heat away from the cylinders. Acetylene is very
different from city or furnace gas. Always refer to acetylene by its full name and not
by the word gas alone. Acetylene is nontoxic; however, it is an anesthetic and if
present in great enough concentrations, is an asphyxiant and can produce
suffocation.
CAUTION
If acetylene cylinders have been stored or transported horizontally (on their sides),
stand cylinders vertically (upright) for 45 minutes prior to (before) use.
Proper Maintenance and Storage
Acetylene cylinders must be handled with care to avoid damage to the valves or the
safety fuse plug. The cylinders must be stored upright in a well ventilated, well
protected, dry location at least 20 feet from highly combustible materials such as oil,
paint, or excelsior.
• Always keep valve protection caps be in place, handtight, except when
cylinders are in use.
• Do not store the cylinders near radiators, furnaces, or in any area with above
normal temperatures. In tropical climates, take care not to store acetylene
where the temperature exceeds 137°F. Heat increases the pressure in the
cylinder, which may cause the safety fuse plug to blow out.
• Locate storage areas away from elevators, gangways, or other places where
there is danger of cylinders being knocked over or damaged by falling objects.
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Keep cylinders at a safe distance from the welding operation to reduce the
possibility of sparks, hot slag, or flames reaching them.
Keep cylinders away from radiators, piping systems, layout tables, etc., which
may be used for grounding electrical circuits.
Use nonsparking tools when changing fittings on cylinders of flammable gases.
Use a suitable truck, chain, or strap to prevent cylinders from falling or being
knocked over while in use.
Store compressed gas cylinders in a safe place with good ventilation. Acetylene
cylinders and oxygen cylinders should be kept apart.
Proper Use
Never use acetylene without reducing the pressure with a suitable pressurereducing regulator.
Never use acetylene at pressures exceeding 15 psi. Higher pressure can cause
an explosion.
Before attaching pressure regulators, open each acetylene cylinder valve for an
instant to blow dirt out of the nozzles.
Wipe the connection seat with a clean cloth.
Do not stand in front of valves when opening them.
Be sure the regulator tension screw is released before opening the cylinder
valve.
Always open the valve slowly to avoid strain on the regulator gauge that
records the cylinder pressure.
Do not open the valve more than one and one-half turns. Usually, one-half turn
is sufficient.
Always use the special T-wrench provided for the acetylene cylinder valve.
Leave this wrench on the stem of the valve while the cylinder is in use so the
acetylene can be quickly turned off in an emergency.
Never open an acetylene cylinder valve near other welding or cutting work.
Thaw outlet valves with warm water if they become clogged with ice. Do not
use scalding water or an open flame.
Proper Testing
• Never test for an acetylene leak with an open flame; test all joints with soapy
water. If a leak occurs around the valve stem of the cylinder, close the valve
and tighten the packing nut.
• Cylinders leaking around the safety fuse plug should be taken outdoors, away
from all fires and sparks. Once outside, open the valve slightly to permit the
contents to escape.
• If an acetylene cylinder catches fire, it usually can be extinguished with a wet
blanket. A burlap bag wet with calcium chloride solution is effective for such an
emergency. If these options fail, spray a stream of water on the cylinder to
keep it cool.
• Equipment Handling
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Never interchange acetylene regulators, hoses, or other apparatus with similar
equipment intended for oxygen.
Always turn the acetylene cylinder so the valve outlet points away from the
oxygen cylinder.
When returning empty cylinders, make certain the valves are closed to prevent
residual acetylene or acetone solvent from escaping and screw on protecting
caps.
Make sure that all gas apparatus is installed properly, is in good working
condition, and shows UL or FM approval.
Handle all compressed gas with extreme care and keep cylinder caps on when
not in use.
Make sure that all compressed gas cylinders are secured to the wall or other
structural supports. Keep acetylene cylinders in a vertical position.
Oxygen Cylinders
Always refer to oxygen by its full name and not by the word air alone. Oxygen should
never be used as air in any way.
WARNING
Do not substitute oxygen for compressed air in pneumatic tools. Do not use oxygen to
blow out pipe lines, test radiators, purge tanks or containers, or to "dust" clothing or
work.
Proper Storage and Handling
1. Do not store oxygen cylinders near highly combustible material. This warning
applies especially to oil and grease, reserve stocks of carbide and acetylene or
other fuel gas cylinders, any other substance likely to cause or accelerate fire;
or in an acetylene generator compartment.
2. Use a noncombustible partition to separate oxygen cylinders stored in outside
generator houses from the generator or carbide storage rooms. The partition
must have a fire resistance rating of at least one hour, have no openings, and
be gastight.
3. Separate stored oxygen cylinders from fuel gas cylinders or combustible
materials (especially oil or grease) by a minimum distance of 20 feet or by a
noncombustible barrier at least 5 feet high with a fire-resistance rating of at
least one-half hour.
4. Where a liquid oxygen system supplies gaseous oxygen for welding or cutting
and is combined with a bulk storage system, it must comply with the provisions
of the Standard for Bulk Oxygen Systems at Consumer Sites, NFPA No. 5661965, National Fire Protection Association.
5. Do not handle oxygen cylinders roughly; take care when using or moving
oxygen cylinders to avoid dropping, knocking over, or striking the cylinders
with heavy objects.
6. Set aside all oxygen cylinders with leaky valves or safety fuse plugs and discs
and mark them for the supplier's attention. Do not tamper with or attempt to
repair oxygen cylinder valves. Do not use a hammer or wrench to open valves.
WARNING
Oil or grease in the presence of oxygen will ignite violently, especially in an enclosed
pressurized area.
Proper Use:
1. Before attaching the pressure regulators, open each oxygen cylinder valve for
an instant to blow out dirt and foreign matter from the nozzle. Wipe the
connection seat with a clean cloth. Do not stand in front of the valve when
opening it.
2. Open the oxygen cylinder valve slowly to prevent damage to regulator highpressure gauge mechanism. Be sure that the regulator tension screw is
released the before opening the valve. When not in use, close the cylinder
valve and screw on the protecting caps to prevent damage to the valve.
3. When the oxygen cylinder is in use, open the valve to the full limit to prevent
leakage around the valve stem.
4. Always use regulators on oxygen cylinders to reduce the cylinder pressure to a
low working pressure. High cylinder pressure will burst the hose.
5. Never interchange oxygen regulators, hoses, or other apparatus with similar
equipment intended for other gases.
MAPP Gas Cylinders
MAPP gas is a mixture of stabilized methylacetylene and propadiene. This product was
developed as a fuel for welding, brazing, cutting, flame hardening, and metallizing
operations. It has many of the physical properties of acetylene, but lacks its shock
sensitivity and therefore can be stored and shipped in lighter containers. MAPP gas
vaporizes when the valve is opened and is difficult to detect visually. However, MAPP
gas has an obnoxious odor detectable at 100 parts per million, a concentration
1/340th of its lower explosive limit in air.
Repair any leaks in MAPP gas cylinders immediately. If repaired when detected, leaks
pose little or no danger. Even though MAPP gas toxicity is rated very slight, high
concentrations (5000 part per million) may have an anesthetic affect if leaks are
ignored.
Store liquid MAPP gas around 70°F and under 94 psig pressure. Proper clothing must
be worn to prevent injury to personnel. Once released into the open air, liquid MAPP
gas boils at -36 to -4°F. This causes frost-like burns when the gas contacts the skin.
MAPP gas has some safety advantages that should be considered when choosing a
process fuel gas. These advantages include:
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2.
3.
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6.
MAPP gas cylinders do not detonate when dented, dropped, or incinerated.
MAPP gas can be used safely at the full cylinder pressure of 94 psig.
Liquified fuel is insensitive to shock.
Explosive limits of MAPP gas are low compared to acetylene.
Leaks can be detected easily by the strong smell of MAPP gas.
MAPP cylinders are easy to handle because of their light weight.
Fuel Gas Cylinders
Although acetylene is the most familiar fuel gas used for cutting and welding,
propane, natural gas, and propylene also are used.
Proper Storage and Handling
The major hazard of compressed gas is the possibility of sudden release of the gas by
removing or breaking off the valve. Escaping gas under high pressure will cause the
cylinder to act as a rocket, smashing into people and property. Proper storage and
handling will help to eliminate some of the hazards that can cause serious incidents to
occur.
Some guidelines for storage and handling include the following:
• Handle cylinders with respect. Do not drop, strike, or use cylinders as rollers.
• An arc strike on a cylinder will damage the cylinder, possibly fracture it, and
require the cylinder to be condemned and discarded from service.
• Store fuel gas cylinders vertically in a specified, cool, well-ventilated area or
outdoors. The cylinder's temperature should never be allowed to exceed 130°F.
• Store fuel gas cylinders separate from oxygen cylinders and separate from
combustible materials.
• All cylinders must have their caps on, and cylinders, whether filled or empty,
should have the valve closed. Do not use hammers or wrenches to open
cylinder valves fitted with hand wheels.
• Take care to protect the valve from damage or deterioration.
• Mark cylinders empty (as "MT") and close the valves to prohibit contamination
from entering.
• Attach a regulator when gas cylinders are used and secure the cylinder by
chains or clamps to prevent falling.
• Securely mount cylinders for portable apparatuses in specially designed
cylinder trucks.
• Never use electromagnetic cranes to move cylinders. They should never be in
an electric circuit so that the welding current could pass through them.
Fire Safety Precautions
Escaping fuel gas also can be a fire or explosion hazard. In a fire, special precautions
should be taken for acetylene cylinders. All acetylene cylinders are equipped with one
or more safety relief devices filled with a low melting point metal. This fusible metal
melts at about the boiling point of water (212°F). If fire occurs on or near an
acetylene cylinder, the fuse plug will melt. The escaping acetylene may ignite and will
burn with a roaring sound.
In case of fire:
• Immediately evacuate all people from the area. It is difficult to put out such a
fire.
• The best action is to put water on the cylinder to keep it cool and to keep all
other acetylene cylinders in the area cool.
• Attempt to remove the burning cylinder from close proximity to other acetylene
cylinders, from flammable or hazardous materials, or from combustible
buildings.
• It is best to allow the gas to burn inside the cylinder rather than to allow
acetylene to escape, mix with air, and possibly explode.
Consider these guidelines for small flame fires:
• If the fire on a cylinder is a small flame around the hose connection, the valve
stem, or the fuse plug, try to put it out as quickly as possible.
• A wet glove, wet heavy cloth, or mud slapped on the flame will frequently
extinguish it.
• Thoroughly wetting the gloves and clothing will help protect the person
approaching the cylinder.
• Avoid getting in line with the fuse plug that might melt at any time.
Hoses
In the United States, the color green is used for oxygen hoses, red for acetylene or
fuel gas, and black for inert gas or compressed air. The international standard calls
for blue for oxygen and orange for fuel gas.
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Use only approved gas hoses for flame cutting or welding with oxyfuel gas
equipment. Single lines, double vulcanized, or double multiple stranded lines
are available.
Do not use new or stored hose lengths without first blowing them out with
compressed air to eliminate talc or accumulated foreign matter which might
enter and clog the torch parts.
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Do not allow hoses to come in contact with oil or grease because these
chemicals penetrate and deteriorate rubber and constitute a hazard with
oxygen.
Always protect hoses from being walked on or run over. Avoid kinks and
tangles. Do not leave hoses where anyone can trip over them and result in
personal injury, damaged connections, or cylinders being knocked over. Do not
work with hoses placed over the shoulder, around the legs, or tied to the waist.
Protect hoses from hot slag, flying sparks, and open flames. Never force hose
connections that do not fit. Do not use white lead, oil, grease, or other pipefitting compounds for connections on hose, torch, or other equipment.
Never crimp hose to shut off gases.
Inspection and Repair
• Hoses should be periodically inspected for burns, worn places, or leaks at the
connections.
• Hoses must be kept in good repair and should be no longer than necessary.
• Examine all hoses periodically for leaks by immersing them in water while
under pressure. Do not use matches to check for leaks in acetylene hose.
Repair leaks by cutting the hose and inserting a brass splice. Do not use tape
for mending. Replace hoses, if necessary.
• Make sure that hoses are securely attached to torches and regulators before
using.
• The size of hose should match the connectors, regulators, and torches.
• Connections on hoses are right-handed for inert gases and oxygen, and lefthanded for fuel gases.
• The nuts on fuel gas hoses are identified by a groove machined in the center of
the nuts.
Topic Summary
Please take a moment to review these major points before you continue with the next
topic.
• Acetylene cylinders must be stored upright in a well-ventilated, well-protected,
dry location at least 20 feet from highly combustible materials such as oil,
paint, or excelsior.
• Never use acetylene at pressures in excess of 15 psi. Higher pressure can
cause an explosion.
• Never test for an acetylene leak with an open flame; test all joints with soapy
water.
• Never interchange acetylene regulators, hose, or other apparatus with similar
equipment intended for oxygen.
• If an acetylene cylinder should catch fire, it usually can be extinguished with a
wet blanket. A burlap bag wet with calcium chloride solution is effective for
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such an emergency. If these fail, spray a stream of water on the cylinder to
keep it cool.
Oxygen cylinders in storage must be separated from fuel gas cylinders or
combustible materials (especially oil or grease) by a minimum distance of 20
feet or by a noncombustible barrier at least 5 feet high and having a fireresistance rating of at least one-half hour.
MAPP gas is a mixture of stabilized methylacetylene and propadiene. Store
liquid MAPP gas around 70°F and under 94 psig pressure.
Escaping fuel gas can be a fire or explosion hazard.
A wet glove, wet heavy cloth, or mud slapped on the flame will frequently
extinguish a fire on a cylinder if it is a small flame around the hose connection,
the valve stem, or the fuse plug.
MAPP gas has advantages which include:
1. Cylinders will not detonate when dented, dropped, or incinerated.
2. It can be used safely at the full cylinder pressure of 94 psig.
3. Liquified fuel is insensitive to shock.
4. Explosive limits of MAPP gas are low compared to acetylene.
5. The strong smell of MAPP gas makes detecting leaks easy.
Cylinders are lightweight and easy to handle.
Topic 6: Safety Precautions in Arc Welding and Gas Shielded Arc
Welding
In the arc cutting process, intense heat of the electric arc melts away the metal. This
topic explains safety precautions in arc welding and cutting by covering hazards in
electric currents, welding machines, and the use of protective screens. This topic also
covers plasma arc cutting and welding and air carbon arc cutting and welding.
After completing this topic, you will be able to:
• Describe plasma arc welding, air carbon arc welding and gas shielded arc
welding
• List the three causes of hazardous radiation and light in welding
• Define hazard evaluation and control methods for physical agents
• Describe the five variables that can account for the amount of metal fumes and
gases and risk to which a welder is exposed
Electric Circuits
A shock hazard is associated with all electrical equipment, including extension lights,
electric hand tools, and all types of electrically powered machinery. Ordinary
household voltage (115 V) is higher than the output voltage of a conventional arcwelding machine.
WARNING
Welding machine, Model 301, AC/DC, Heliarc with inert gas attachment, NSN 343100-235-4728, may cause electrical shock if not properly grounded.
If one is being used, contact Castolin Institute, 4462 York St. Denver, Colorado
80216.
Although the AC and DC open circuit voltages are low compared to voltages used for
lighting circuits and motor-driven shop tools, these voltages can cause severe shock,
particularly in hot weather when the welder is sweating. Consequently, the following
precautions should always be observed:
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Check the welding equipment to make certain that electrode connections and
insulation on holders and cables are in good condition.
Keep hands and body insulated from both the work and the metal electrode
holder.
Avoid standing on wet floors or coming in contact with grounded surfaces.
Perform all welding operations within the rated capacity of the welding cables.
Excessive heating will impair the insulation and damage the cable leads.
Inspect the cables periodically for looseness at the joints, defects due to wear,
or other damage. Defective or loose cables are a fire hazard. Defective
electrode holders should be replaced and connections to the holder tightened.
Locate or shield welding generators to prevent dust, water, or other foreign
matter from entering the electrical windings or bearings.
Use disconnect switches with all power sources so they can be disconnected
from the main lines for maintenance.
Welding Machines
Metal cutting in welding is the severing or removing metal by a flame or arc. The
most common cutting processes are:
• Arc cutting in which intense heat of electric arc melts away the metal.
• Oxygen cutting in which metal is heated by gas flame and an oxygen jet does
the cutting.
Motor generator welding machines
Motor generator welding machines feature complete separation of the primary power
and the welding circuit since the generator is mechanically connected to the electric
rotor. A motor generator-type arc welding machine must have a power ground on the
machine. Metal frames and cases of motor generators must be grounded since the
high voltage from the main line does come into the case. Stray current may cause a
severe shock to the operator if he should contact the machine and a good ground.
When electric generators powered by internal combustion engines are used inside
buildings or in confined areas, the engine exhaust must be vented to the outside
atmosphere.
With the machine off or unplugged, check welding equipment to make sure the
electrode connections and the insulation on holders and cables are in good condition.
A trained electrician should investigate all serious trouble.
Transformer- and rectifier-type welding machines
In transformer- and rectifier-type welding machines, the metal frame and cases must
be grounded to the earth. The work terminal of the welding machine should not be
grounded to the earth.
When large weldments, like ships, buildings, or structural parts are involved, it is
normal to have the work terminal of many welding machines connected to it.
Phase and polarity
Machines should be connected to the proper phase and have the same polarity.
Corrections must be made before welding begins. Check by measuring the voltage
between the electrode holders of the different machines. Phases of a three-phase
power line must be accurately identified when paralleling transformer welding
machines to ensure that the machines are on the same phase and in phase with one
another. To check, connect the work leads together and measure the voltage between
the electrode holders of the two machines. This voltage should be practically zero. If
it is double the normal open circuit voltage, it means that either the primary or
secondary connections are reversed. If the voltage is approximately one and one-half
times the normal open circuit voltage, it means the machines are connected to
different phases of the three-phase power line.
The situation also can occur in direct current power sources when they are connected
to a common weldment. If one machine is connected for straight polarity and one for
reverse polarity, the voltage between the electrode holders will be double the normal
open circuit voltage. Precautions should be taken to see that all machines are of the
same polarity when connected to a common weldment.
Remember these important rules:
• Do not operate the polarity switch while the machine is operating under
welding current load. Consequent arcing at the switch will damage the contact
surfaces, and the flash may burn the person operating the switch.
• Do not operate the rotary switch for current settings while the machine is
operating under welding current load. Severe burning of the switch contact
surfaces will result. Operate the rotary switch while the machine is idling.
• Disconnect welding machines from the power supply when they are left
unattended.
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The work clamp must be securely attached to the work before the start of the
welding operation.
Place welding machines where they have adequate ventilation and ventilation
ports are not obstructed.
Holders
The welding electrode holders must be connected to machines with flexible cables for
welding application. Use only insulated electrode holders and cables. There can be no
splices in the electrode cable within 10 feet of the electrode holder. Splices, if used in
work or electrode leads, must be insulated. Wear dry, protective covering on hands
and body.
Partially used electrodes should be removed from the holders when not in use. A
place should be provided to hang up or lay down the holder where it cannot come in
contact with people or conducting objects.
Protective Screens
When welding is done near other personnel, portable screens should be used to
protect their eyes from the arc or reflected glare. Additionally, screens should be
used, when necessary, to prevent drafts of air from interfering with the stability of
the arc.
Arc welding operations give off an intense light. Use snap-on light-proof screens to
cover the windows of the welding truck to provide protection when welding at night.
Radiation and Light
Ultraviolet radiation (UV) is generated by the electric arc in the welding process. Skin
exposure to UV can result in severe burns, in many cases without warning. UV
radiation also can damage the lens of the eye. Many arc welders are aware of the
condition known as "arc-eye," a sensation of sand in the eyes. This condition is
caused by excessive eye exposure to UV. Exposure to ultraviolet rays also may
increase the skin effects of some industrial exposure to infrared radiation (IR)
produced by the electric arc and other flame cutting equipment may heat the skin
surface and the tissues immediately below the surface. Except for this effect, which
can progress to thermal burns in some situations, infrared radiation is not dangerous
to welders. Most welders protect themselves from IR and UV radiation with a welder's
helmet (or glasses) and protective clothing
Exposure of the human eye to intense visible light can produce adaptation, pupillary
reflex, and shading of the eyes. Such actions are protective mechanisms to prevent
excessive light from being focused on the retina. In the arc welding process, the
welder's helmet prevents most exposure of the eyes to intense visible light. However,
some individuals have sustained retinal damage due to careless "viewing" of the arc.
The arc should never be observed without eye protection.
Plasma Arc Cutting and Welding
Plasma arc welding is a process in which coalescence (blending of materials) is
produced by heating with a constricted arc between an electrode and the work piece
(transfer arc) or the electrode and the constricting nozzle (nontransfer arc). Shielding
comes from the hot ionized gas issuing from the orifice, which may be supplemented
by an auxiliary source of shielding gas. Shielding gas may be an inert gas or a
mixture of gases, pressure may or may not be used, and filler metal may or may not
be supplied. Because plasma welding is similar in many ways to the tungsten arc
process, the safety considerations for plasma arc welding are the same as for gas
tungsten arc welding.
The plasma arc welding process requires adequate ventilation because the brightness
of the plasma arc causes air to break down into ozone. The bright arc rays also cause
fumes from the hydrochlorinated cleaning materials or decreasing agents to break
down and form phosgene gas. For this reason, cleaning operations with these
materials should be shielded from the arc rays of the plasma arc.
Use these guidelines for PPE:
• Use normal precautions for protection against arc flash and heat burns when a
pilot arc is operated continuously.
• Wear suitable clothing to protect exposed skin from arc radiation.
• Use adequate eye protection when observing a high-frequency discharge to
center the electrode.
Power and Ventilation Guidelines
Follow these rules when using the equipment in arc welding and cutting:
• Ground accessory equipment, such as wire feeders, arc voltage heads, and
oscillators. If not grounded, insulation breakdown may cause these units to
become electrically "hot" with respect to ground.
• Turn off welding power before electrodes are adjusted or replaced.
• Use adequate ventilation, particularly when welding metals with high copper,
lead, zinc, or beryllium contents.
Air Carbon Arc Cutting and Welding
Air carbon arc cutting is an arc cutting process in which metals to be cut are melted
by the heat of a carbon arc and the molten metal removed by a blast of air. A highvelocity air jet traveling parallel to the carbon electrode strikes the molten metal
puddle just behind the arc and blows the molten metal out of the immediate area.
The area of the cut is small and, since the metal is melted and removed quickly, the
surrounding area does not reach high temperatures.
The air carbon arc cutting process is used for cutting metal, gouging out defective
metal, removing old or inferior welds, root gouging full penetration welds, preparing
joints, and preparing grooves for welding.
This process also is used when slightly ragged edges are not objectionable. It is not
recommended for weld preparation for stainless steel, titanium, zirconium, and other
similar metals without subsequent cleaning. This cleaning, usually by grinding, must
remove all surface carbonized material adjacent to the cut. The process can be used
to cut these materials for scrap for remelting.
What are the Power Requirements for Air carbon cutting and welding?
Conventional welding machines with constant current are normally used with this
process. When using a constant voltage (CV) power source, the machine should be
operated within its rated output of current and duty cycle. For special applications,
alternating current power sources with conventional drooping characteristics can also
be used, but AC type carbon electrodes must be used.
Special heavy-duty high current machines are made specifically for the air carbon arc
process because of extremely high currents used for the large size carbon electrodes.
Air pressure must range from 80 to 100 psi. The volume of compressed air required
ranges from as low as 5 cubic feet/minute up to 50 cubic feet/minute for the largestsize carbon electrodes.
The air blast of air carbon arc welding will cause the molten metal to travel a very
long distance. Metal deflection plates should be placed in front of the gouging
operation, and all combustible materials should be moved away from the work area.
At high-current levels, the mass of molten metal removed is quite large and will
become a fire hazard if not properly contained.
A high noise level is associated with air carbon arc welding. At high currents with high
air pressure, a very loud noise occurs. Arc cutters must wear ear protection, earmuffs
or earplugs.
The process is widely used for back gouging, preparing joints, and removing defective
metal.
This reduces the tendency toward distortion and cracking. The air carbon arc can be
used for cutting or gouging most common metals
Gas Shielded Arc Welding
Welding processes should be shielded from the air to obtain a high molten puddle of
metal for a quality weld deposit. In shielded metal arc welding, shielding is
accomplished by gases produced from the disintegration of the coating in the arc.
Shielding occurs by surrounding the arc area with a localized gaseous atmosphere
throughout the welding operation at the molten puddle area.
Gas shielded arc welding processes have certain dangers associated with them. These
hazards, which are either peculiar to or increased by gas shielded arc welding, include
arc gases, radiant energy, radioactivity from thoriated tungsten electrodes, and metal
fumes.
Ozone
Ozone concentration increases with the type of electrodes used, amperage, extension
of arc tine, and increased argon flow. If welding is carried out in confined spaces and
poorly ventilated areas, the ozone concentration may increase to harmful levels. The
exposure level to ozone is reduced through good welding practices and properly
designed ventilation systems.
Nitrogen Oxides
Natural ventilation may be sufficient to reduce the hazard of exposure to nitrogen
oxides during welding operations, provided all three ventilation criteria are satisfied.
Nitrogen oxide concentrations will be very high when performing gas tungsten-arc
cutting of stainless steel using a 90 percent nitrogen-10 percent argon mixture. Also,
high concentrations have been found during experimental use of nitrogen as a shield
gas. Good industrial hygiene practices dictate that mechanical ventilation be used
during welding or cutting of metals.
Carbon Dioxide and Carbon Monoxide
Carbon dioxide is disassociated by the heat of the arc to form carbon monoxide. The
hazard from inhalation of these gases will be minimal if ventilation requirements are
satisfied.
WARNING
The vapors from some chlorinated solvents (e.g., carbon tetrachloride,
trichloroethylene, and perchloroethylene) break down under the ultra-violet
of an electric arc and forma toxic gas. Avoid welding where such vapors are
Furthermore, these solvents vaporize easily and prolonged inhalation of the
be hazardous. These organic vapors should be removed from the work area
radiation
present.
vapor can
before
welding is begun. Ventilation must be provided for control of fumes and vapors in the
work area.
Vapors of Chlorinated Solvents
Ultraviolet radiation from the welding or cutting arc can decompose the vapors of
chlorinated hydrocarbons, such as perchloroethylene, carbon tetrachloride, and
trichloroethylene, to form highly toxic substances. Eye, nose, and throat irritation can
result when the welder is exposed to these substances. Sources of the vapors can be
wiping rags, vapor degreasers, or open containers of the solvent. Since this
decomposition can occur even at a considerable distance from the arc, the source of
the chlorinated solvents should be located so that no solvent vapor reaches the
welding or cutting area.
Radiant Energy
Electric arcs, as well as gas flames, produce ultraviolet and infrared rays that can
have a harmful effect on the eyes and skin upon continued or repeated exposure. The
usual effect of ultraviolet rays is to "sunburn" the surface of the eye, which is painful
and disabling but generally temporary. Ultraviolet radiation may also produce the
same effects on the skin as a severe sunburn. The production of ultraviolet radiation
doubles when gas shielded arc welding is performed. Infrared radiation has the effect
of heating the tissue with which it comes in contact. Therefore, if the heat is not
sufficient to cause an ordinary thermal burn, the exposure is minimal. Leather and
wool clothing is preferable to cotton clothing during gas shielded arc welding. Cotton
clothing disintegrates in one day to two weeks, presumably because of the high
ultraviolet radiation from arc welding and cutting.
Radioactivity From Thoriated Tungsten Electrodes
Gas tungsten arc welding using these electrodes may be employed with no significant
hazard to the welder or other room occupants. Generally, special ventilation or
protective equipment other than that previously specified is not needed for protection
from exposure hazards associated with welding with thoriated tungsten electrodes.
Metal Fumes
The physiological response from exposure to metal fumes varies depending upon the
metal being welded. Ventilation and personal protective equipment must be employed
to prevent hazardous exposure.
Hazards
Welding and cutting may produce metal fumes and gases that can make you very
sick. The degree of risk you face from these activities depends on:
• The welding method (such as MIG, TIG, or stick)
• What the welding rod (electrode) is made of
• Filler metals and base metals (such as mild steel and stainless steel)
•
•
Paints and other coatings on the metals being welded
Ventilation
Metals
• Stainless steel contains nickel and chromium. Nickel can cause asthma. Nickel
and chromium can cause cancer. Chromium can cause sinus problems and
"holes" between the nostrils.
• Mild steel (red iron) and carbon steel contain manganese. Manganese can
cause Parkinson's disease, which cripples the nerves and muscles.
• Zinc in galvanized metal or in paint (on welded surfaces) can cause metal fume
fever. It feels like the flu and goes away in a few hours or days after exposure
ends.
Coatings and Residues
• Lead (in some paints) can cause lead poisoning - headaches, sore muscles and
joints, nausea, stomach cramps, irritability, memory loss, anemia, and kidney
and nervous system damage. If lead dust goes home on work clothes/shoes, it
can make your family sick, most of all your children.
• Cadmium (in some paints and fillers) can cause kidney problems and cancer.
Solvents
Welding through or near some solvents can produce phosgene, a poisonous gas. The
gas can cause fluid in the lungs. You may not notice the problem until hours after you
quit welding. But fluid in your lungs can kill you.
Gases
• When carbon dioxide is used for shielding, carbon monoxide can form and kill
you.
• The welding arc can form ozone and nitrous oxides from the air. MIG and TIG
welding make the most ozone, most of all when aluminum is welded. These
fumes irritate the eyes, ears, nose, throat, and lungs and can damage the
lungs.
• Nitrous oxides can cause fluid in the lungs.
Controls
Methods to evaluate hazards include air sampling for detecting metal fumes, flux
components, and evolved gases. Control methods for welding and cutting include
general and local ventilation, but OSHA specifies other requirements:
•
You must have good ventilation.
•
•
•
•
•
•
•
•
You must remove all paint and solvents before welding or torch cutting. Follow
written instructions. Make sure all residues are removed.
Use the safest welding method for the job. Stick welding makes much less
fume than flux core welding.
Use welding rods that produce a low fume, as 90 percent of the fume can come
from the rod. Welding guns that extract fumes can capture 95 percent of the
fume.
In a confined space, follow all the OSHA confined-space rules like air
monitoring, not storing torches in the space, and ventilation.
Use local-exhaust ventilation to remove fumes and gases at their source in still
air. Keep the exhaust hood four to six inches from the fume source.
Use air blowers to blow fumes away from you when you are outdoors and it's
windy.
Keep your face far from the welding plume.
If the ventilation is not good, use a respirator. If respirators are used, your
employer must have a full respiratory protection program. This means proper
selection and fitting of respirators, medical screening to be sure a worker can
wear a respirator, and worker training. Correct respirator storage and cleaning
and an evaluation of the program are needed.
OSHA has limits for exposure to metals, gases, and total fumes during welding, but
these limits may not protect you enough because they are out of date. The National
Institute for Occupational Safety and Health (NIOSH) says welding fumes may cause
cancer, so keep the fume levels as low as possible.
Topic Summary
Please take a moment to review these key points before you continue with the next
topic.
• Metal cutting in welding is the severing or removing of metal by a flame or arc.
The most common cutting processes are:
• Arc cutting in which intense heat of electric arc melts away the metal.
• Oxygen cutting in which metal is heated by gas flame and an oxygen jet does
the cutting.
• Screens can be used to:
• Protect eyes of other personnel from the arc or reflected glare.
• Prevent drafts of air from interfering with the stability of the arc.
• Cover the windows of the welding truck to provide protection when welding at
night.
• The output voltage of a conventional arc welding machine is lower than
ordinary household voltage (115 V).
• Plasma arc welding is a process in which coalescence is produced by heating
with a constricted arc between an electrode and the work piece (transfer arc)
or the electrode and the constricting nozzle (nontransfer arc).
•
•
•
•
•
•
•
•
•
Air carbon arc cutting is an arc cutting process in which metals to be cut are
melted by the heat of a carbon arc and the molten metal removed by a blast of
air. The process is widely used for back gouging, preparing joints, and
removing defective metal.
In shielded metal arc welding, shielding from the air is accomplished by gases
produced by the disintegration of the coating in the arc.
With gas shielded arc welding, shielding from the air is accomplished by
surrounding the arc area with a localized gaseous atmosphere throughout the
welding operation at the molten puddle area.
Gas shielded arc welding is associated with certain dangers, including:
o Arc gases
o Radiant energy
o Radioactivity from thoriated tungsten electrodes
o Metal fumes
Welding and cutting may produce metal fumes and gases that can make you
very sick. The risk depends on: the welding method (such as MIG, TIG, or
stick); what the welding rod (electrode) is made of; filler metals and base
metals (such as mild steel and stainless steel); paints and other coatings on
the metals being welded, and ventilation.
Most welders protect themselves from IR and UV radiation with a welder's
helmet (or glasses) and protective clothing.
To avoid retinal damage, never observe the welding arc without eye protection.
OSHA has limits for exposure to metals, gases, and total fumes during welding,
but these limits may not protect you enough, because they are out of date.
NIOSH says welding fumes may cause cancer, so selecting fume reduction
methods is important to your health.
Stick welding makes much less fume than flux core welding.
Lesson Summary
This lesson contains information and instruction about welding and cutting. By
completing this lesson, you should have the knowledge to discuss the following
topics. Take a moment to see if you can do the following:
•
•
•
•
Describe the three most frequently cited OSHA violations related to welding.
Define the general welding hazards that PPE should reduce or eliminate.
Describe ventilation methods used in welding and cutting work.
Describe general precautions for assuring safe handling of oxyfuel welding
equipment
•
•
Describe plasma arc welding, air carbon arc welding and gas shielded arc
welding
Describe the five variables that can account for the amount of metal fumes and
gases and risk to which a welder is exposed
Electrical Part I
Introduction
Every day, four construction workers die on the job in this country. Think about
construction fatalities, and the first things that come to mind are probably trenching
or falls. However, one of the leading causes of worker deaths in construction is
electrocution.
Many workers are unaware of the potential electrical hazards in their work
environment, making them more vulnerable to the danger of electrocution.
Sometimes, it is just a matter of not knowing the environment or not being aware of
all energized power sources, from overhead and underground power lines to damaged
receptacles and connectors. People need to increase their awareness of electrical
hazards in construction.
Remember this: Treat electricity with the respect it demands, and it will serve you
efficiently and effectively.
Lesson Overview
Welcome to the "Electrical Part 1" lesson of the Turner OSHA Certification course.
This lesson introduces electrical hazards, one of the easily overlooked hazards that
are common in the construction industry. In this lesson, you will learn how electricity
works and the effects that electricity has on the human body. You will also learn
about common electrical hazards and general OSHA requirements.
Upon completing this lesson, you will be able to:
•
•
•
•
•
Explain how electricity works and define the fundamental concepts of electricity
Describe the effects of electricity on the human body including shocks, burns,
and other injuries
Recognize common electrical hazards
State OSHA requirements on installation safety concerning examination and
installation of equipment, guarding, overcurrent protection, and grounding
State OSHA requirements for electricity, including safety-related work
practices, safety-related maintenance and environmental considerations, and
safety requirements for special equipment
Why Learn This Lesson?
Working in the construction industry requires extra attention to safety. Working
conditions change from minute to minute and from day to day because of the nature
of the construction industry. Even as hazards are recognized and eliminated, new
hazards arise that may be in plain view. One of the leading hazards is electricity,
which is common to every construction job site.
According to the Bureau of Labor Statistics, electrocutions dropped below 300 for the
first time in five years in 1999. Unfortunately, construction workers still represent 45
percent of job site electrocution deaths.
"Training and education are key to increasing awareness about electrical hazards in
construction," says Bruce Swanson, director of OSHA's construction directorate. "If
we want to reduce the fatality rate, we need to make sure employers and workers are
better trained in OSHA requirements and safety work practices."
The information in this lesson will help you effectively control and manage the
hazards associated with working with and around temporary and permanent
electricity.
Topic 1: General Information
What Is Electricity - The History of Exploration
Electricity has been around since the beginning of time in the forms of lightning and
static electricity. In 600 B.C. in Greece, it was observed that amber rubbed with wool
would attract light objects such as straw, feathers, and bits of wood. For centuries
this strange, inexplicable property was thought to be unique to amber.
16th Century
Two thousand years later, in the 16th century, William Gilbert proved that many
other substances are electric (from electron, the Greek word for amber) and that they
have two electrical effects. Amber, when rubbed with fur, acquires resinous
electricity, while glass, when rubbed with silk, acquires vitreous electricity. Electricity
repels the same kind of electricity and attracts the opposite kind. Scientists thought
that the friction actually created the electricity (their word for charge). They did not
realize that an equal amount of opposite electricity remained on the fur or silk.
18th Century
In 1747, Benjamin Franklin in America and William Watson (1715-87) in England
independently reached the same conclusion: all materials possess a single kind of
electrical "fluid" that can penetrate matter freely but that can be neither created nor
destroyed. The action of rubbing merely transfers the "fluid" from one body to
another, electrifying both. Franklin and Watson originated the principle of
conservation of charge: the total quantity of electricity in an insulated system is
constant.
Franklin defined the fluid, which corresponded to vitreous electricity, as positive and
the lack of fluid as negative. Therefore, according to Franklin, the direction of flow
was from positive to negative -- the opposite of what is now known to be true. A
subsequent two-fluid theory was developed, according to which samples of the same
type attract, whereas those of opposite types repel.
Now we know that electricity is a form of energy, a phenomenon that is a result of
the existence of electrical charge. The theory of electricity and its inseparable effect,
magnetism, is probably the most accurate and complete of all scientific theories. The
understanding of electricity has led to the invention of motors, generators,
telephones, radio and television, X-ray devices, computers, and nuclear energy
systems. Electricity is a necessity to modern civilization.
How Electricity Works
Operating an electrical switch is like turning on a water faucet. Behind the faucet (or
switch) there is a source of water (or electricity), a way to transport it, and pressure
to make it flow. The faucet's water source is a reservoir or pumping station. A pump
provides enough pressure for the water to travel through the pipes. The switch's
electrical source is a power generating station. A generator provides the pressure for
the electrical current to travel through electrical conductors, or wires.
There are two basic rules of electrical action:
• Electricity isn't "live" until current flows.
• Electrical current won't flow until there is a complete loop out from and back to
the power source.
Conductors vs. Insulators
Three factors determine the resistance of a substance to the flow of electricity.
•
•
•
What it is made of
Its size
Its temperature
Substances with very little resistance to the flow of electrical current are called
conductors. Examples are metals.
Substances with such a high resistance that they can be used to prevent the flow of
electrical current are called insulators. Examples are glass, porcelain, plastic, and dry
wood.
Is water a conductor or an insulator?
Pure water is a poor conductor of electricity, but small amounts of impurities, such as
salt and acid (perspiration contains both), make it a ready conductor. Therefore,
although dry wood is a poor conductor, when saturated with water it becomes a ready
conductor. The same is true of human skin. When skin is dry, it is a poor conductor of
electrical current. When it is moist, it readily conducts electricity. Use extreme caution
when working with electricity where there is water in the environment or on the skin.
Qualified Personnel vs. Unqualified Personnel
Two basic terms used in electrical safety are a qualified person and an unqualified
person.
A qualified person is a person who has been trained to avoid electrical hazards when
working on or near exposed energized parts. A qualified person must be trained to
possess the following abilities:
•
•
•
•
Familiar with the safety related work practices required by OSHA
Able to distinguish exposed live parts of electrical equipment
Knowledgeable of the skills and techniques used to determine the nominal
voltages of exposed parts
Knowledgeable of the approach distances to which a qualified person will be
exposed
An unqualified person is someone who has little or no training regarding electrical
hazards. Even though unqualified persons may not be exposed to energized parts,
training should still be given. At a minimum, the unqualified person must be familiar
with any electrical-related safety practice that is necessary for his or her safety. This
could be as simple as telling an unqualified person to shut off a machine if there's a
problem and call a supervisor for assistance.
Topic Summary
Please take a moment to review these major points before you continue with the next
topic.
•
Two basic rules of electrical actions are:
Electricity isn't live until current flows
Electrical current won't flow until there is a complete loop out from and
back to the power source.
Substances with very little resistance to the flow of electrical current are called
conductors. Examples are metals.
Substances with such a high resistance that they can be used to prevent the
flow of electrical current are called insulators. Examples are glass, porcelain,
plastic, and dry wood.
A qualified person is a person who has been trained to avoid electrical hazards
when working on or near exposed energized parts.
An unqualified person is someone who has little or no training regarding
electrical hazards. However, at a minimum, the unqualified person must be
familiar with any electrical-related safety practice that is necessary for his or
her safety.
o
o
•
•
•
•
Topic 2: Effects of Electricity
This topic introduces the effects of electricity on the human body such as shocks,
burns, and other injuries. It also examines the factors that affect the severity of
electrical shocks. Upon completing this topic, you will be able to:
•
•
•
•
Explain how shocks occur
Describe the potential for electrical burns and other injuries
List the factors that affect the severity of electrical shocks
Explain how different degrees of amperes affect the human body
How Shocks Occur
Electricity travels in closed circuits, normally through a conductor. It seeks the easiest
path to the ground, trying to find a conductor, such as metal, wet wood, or water.
Humans are conductors, since 70 percent of the body is water. So if a person touches
an energized bare wire or faulty equipment while grounded, electricity will pass
through the body instantly to the ground, causing a harmful, potentially fatal, shock.
Shock results when the body becomes part of the electrical circuit: current enters the
body at one point and leaves at another.
Metallic parts of electric tools and machines can become energized if there is a break
in the insulation of their wiring. A low-resistance wire between the metallic case of
the tool/machine and the ground - an equipment grounding conductor - provides a
path for the unwanted current to pass directly to the ground. This greatly reduces the
amount of current passing through the body of the person in contact with the tool or
machine. Properly installed, the grounding conductor provides protection from electric
shock.
Shock-Related Injuries
Shock-related injuries include burns, internal injuries, and injuries due to involuntary
muscle contractions.
Electrical Burns
Electrical burns cause tissue damage and are the result of heat generated by the flow
of electric current through the body. Electrical burns are one of the most serious
injuries you can receive and should be given immediate attention.
Flash Burns
High temperatures near the body produced by an electric arc or explosion cause arc
or flash Burns. They should also be attended to promptly.
Thermal Contact Burns
Thermal contact burns occur when skin comes in contact with overheated electric
equipment or when clothing is ignited in an electrical incident.
Internal Injuries
Excessive electricity flowing through the human body can cause serious damage to
internal organs. Resulting medical problems include hemorrhage (or internal
bleeding), tissue destruction, and nerve or muscle damage. These internal injuries
may not be immediately apparent to the victim or observers; however, left untreated,
they can result in death.
Involuntary Muscle Contraction
Normal muscle contraction is caused by very small amounts of electricity that are
created within our bodies. Muscles contract violently when stimulated by excessive
amounts of electricity. These involuntary contractions can damage muscles, tendons,
and ligaments, and may even cause broken bones. If the victim is holding an
electrocuting object, hand muscles may contract, making it impossible to drop the
object and prolonging contact with the current. Also, injury or death may result when
violent muscle contractions cause workers to fall from ladders and scaffolds or
inadvertently strike other objects.
Factors That Affect the Severity of Shocks
Three primary factors affect the severity of the shock a person receives when he or
she is a part of an electrical circuit:
•
•
•
Amount of current flowing through the body (measured in amperes and
determined by voltage and resistance)
Path of the current through the body
Length of time the body is in the circuit
Effects can range from a barely perceptible tingle to severe burns and immediate
cardiac arrest.
What other factors may affect the severity of an electrical shock?
Other factors that may affect the severity of the shock are:
• The voltage of the current
• The presence of moisture in the environment
• The phase of the heart cycle when the shock occurs
• The general health of the person prior to the shock
Degrees of Amperes
Although the exact injuries that result from any given amperage (a unit of electrical
current) are not known, the following table demonstrates this general relationship for
a 60-cycle, hand-to-foot shock of one second's duration.
Current level (in milliamperes)
Probable effect on human body
1 mA
Perception level. Slight tingling sensation.
Still dangerous under certain conditions
(for example, wet conditions).
5 mA
Slight shock felt; not painful but
disturbing. Average individual can let go.
However, strong involuntary reactions to
shocks in this range may lead to injuries.
6-30 mA
Painful shock; muscular control is lost.
This is called the freezing current or "letgo" range.
50-150 mA
Extreme pain, respiratory arrest, severe
muscular contractions. Individual cannot
let go. Death is possible.
1000-4300 mA
Ventricular fibrillation (the rhythmic
pumping action of the heart ceases).
Muscular contraction and nerve damage
occur. Death is most likely.
10,000 mA
Cardiac arrest, severe burns, and
probable death.
Other Factors
In addition to amperes, there are other factors that affect the severity of shocks as
well.
Wet Conditions
Wet conditions are usually the cause of low-voltage electrocutions. Under dry
conditions, human skin is very resistant. Wet skin dramatically drops the body's
resistance.
Dry Conditions: Current = Volts/Ohms = 120/100,000 = 1mA
A barely perceptible level of current
Wet conditions: Current = Volts/Ohms = 120/1,000 = 120mA
Sufficient current to cause ventricular fibrillation
Length of Time the Body Is in the Circuit
When muscular contraction caused by stimulation does not allow the victim to free
himself from the circuit, even relatively low voltages can be extremely dangerous,
because the degree of injury increases with the length of time the body is in the
circuit. Low voltage does not imply low hazard!
100mA for 3 seconds = 900mA for .03 seconds in causing fibrillation
Note that a difference of less than 100 milliamperes exists between a current that is
barely perceptible and one that can kill.
Voltage of the Current
High-voltage electrical energy greatly reduces the body's resistance by quickly
breaking down human skin. Once the skin is punctured, the lowered resistance results
in massive current flow. Ohm's law is used to demonstrate the action.
At 1,000 volts, Current = Volts/Ohms = 1,000/500 = 2 Amps,
which can cause cardiac standstill and serious damage to internal organs.
Topic Summary
Please take a moment to review these key points before you continue with the next
topic.
•
Shock results when the body becomes part of the electrical circuit -- current
enters the body at one point and leaves at another. It occurs in following
situations:
o Touching both wires of an electrical circuit; i.e., a person contacts both
wires of an energized circuit.
o Touching one energized wire and a ground conductor; i.e., a person
contacts one wire of an energized circuit and the ground.
Touching the case of a faulted or short-circuited appliance or machine;
i.e., a metallic part comes into contact with an energized wire while a
person is also in contact with the ground.
Effects of shocks can range from a barely perceptible tingle to severe burns
and immediate cardiac arrest.
Shock-related injuries include burns, internal injuries, and injuries due to
involuntary muscle contractions.
Three primary factors affect the severity of the shock a person receives when
he or she is a part of an electrical circuit:
Amount of current flowing through the body (measured in amperes and
determined by voltage and resistance)
Path of the current through the body
Length of time the body is in the circuit
o
•
•
•
o
o
o
Topic 3: Electrical Hazards
This topic introduces common electrical hazards. Upon completing this lesson, you will
be able to:
• List four common electrical hazards
• Explain why those electrical hazards are dangerous
Electrical Safety
The major causes of electrocutions in the United States fall into one of these areas:
• Contact with power lines
• Path to ground missing or disconnected
• Equipment not used in manner prescribed
• Improper use of extension and flexible cords
Contact With Power Lines
Overhead and buried power lines at your site are especially hazardous because they
carry extremely high voltage. Fatal electrocution is the main risk, but burns and falls
from elevation are also hazards. Using tools and equipment that can contact power
lines increases the risk.
Examples of Equipment That Can Contact Power Lines
• Aluminum paint rollers
• Backhoes
• Concrete pumper trucks
•
•
•
•
•
•
Cranes
Long-handled cement finishing floats
Metal building materials
Metal ladders
Raised dump truck beds
Scaffolds
Sample Incidents
Deaths Due to Contact With Power Lines
Seven employees of a masonry company were erecting a brick wall from a tubular,
welded-frame scaffold approximately 24 feet high. The scaffold had been
constructed only 21 horizontal inches across from a 7,620-volt power line. A
laborer carried a piece of wire reinforcement (10 feet long by 8 inches wide) along
the top section of the scaffold and touched the power line with it. The laborer, who
was wearing leather gloves, received an electric shock and dropped the wire
reinforcement, which fell across the power line and simultaneously contacted the
metal rail of the scaffold, energizing the entire scaffold. A 20-year-old bricklayer
standing on the work platform in contact with the main scaffold was electrocuted.
Crane Boom Too Close to Power Line
A 56-year-old construction laborer was removing forms from a concrete wall
poured several days earlier. As he removed the forms, he wrapped them with a
length of cable called a choker, which was to be attached to a crane. The victim
signaled the operator of the crane to extend the boom and lower the hoist cable.
Both the operator and the victim failed to notice that the boom had contacted a
2,400-volt overhead power line. When the victim reached down to connect the
choker to the hoist cable, he suddenly collapsed. Co-workers provided CPR but
were unable to revive the victim. Only after a rescue squad arrived about four
minutes later did anyone realize that the crane was in contact with a power line -all those present had assumed that the victim had suffered a heart attack.
Crane Boom Swung Into Power Line
A 29-year-old worker was electrocuted when he pushed a crane cable into a
7,200-volt power line. The victim was part of a crew that was constructing a
concrete wall. Before work began, the company safety director made sure that
insulated line hoses were placed over sections of the power line near the job site
and that a safety clearance zone was marked off for arriving cement trucks. After
the wall was poured, one driver cleaned the loading chute of his cement truck with
a water hose mounted on the truck. As he began to pull away, the crew supervisor
yelled to him, asking if the crew could use his water hose to wash out their cement
bucket suspended from the crane. The driver stopped the truck under the power
line, and the victim, not realizing that the truck had moved, swung the boom to
position the bucket behind the truck. When he grasped the handle of the bucket to
pull it down, the crane cable came into contact with the overhead line. The victim
provided a path to ground and was electrocuted.
Path to Ground Missing or Disconnected
If the power supply to the electrical equipment at your site is not grounded or the
path has been broken, fault current may travel through a worker's body, causing
electrical burns or death. Even when the power system is properly grounded,
electrical equipment can change from safe to hazardous instantly because of extreme
conditions and rough treatment.
What is grounding?
The term ground refers to a conductive body, usually the earth. "Grounding" a tool or
electrical system means intentionally creating a low-resistance path to the earth.
When properly done, current from a short or from lightning follows this path, thus
preventing the buildup of voltages that would otherwise result in electrical shock,
injury, or even death.
Sample Incidents
Ground Wire Not Attached
A fan connected to a 120-volt electrical system via an extension cord provided
ventilation for a worker performing a chipping operation from an aluminum
stepladder. The insulation on the extension cord was cut through and exposed
bare, energized conductors that made contact with the ladder. The ground wire
was not attached on the male end of the cord's plug. When the energized
conductor made contact with the ladder, the path to ground included the
worker's body, resulting in death.
Adapter for Three-Prong Cord Not Grounded to Outlet
Two workers were using a 110-volt auger to install tie-down rods for a
manufactured home. The auger had a one-quarter horsepower motor encased
in a metal housing with two handles. One handle had a deadman's switch.
Electricity to the auger was supplied by a series of 50-foot extension cords
running to an adjacent property. Since the outlet at the adjacent property had
no socket for a ground prong, the extension cords were plugged into the outlet
using an adapter, but the ground wire of the adapter was not grounded. Two
of the extension cords had no ground prongs, and some of them were repaired
with electrical tape. The workers had removed their shirts and were sweating.
One worker, holding the deadman's switch, received a shock from a ground
fault in the auger and was knocked back from the machine. The auger then fell
across the other worker, the 24-year-old victim. The first worker knocked the
auger off the victim, but saw that the electric cord was wrapped around the
victim's thigh. He yelled for his co-workers to disconnect the power, which they
did. The workers administered CPR to the victim, but to no avail.
Short in Power Saw/Ungrounded Temporary Power Supply
A 22-year-old carpenter was working at the construction site of large
apartment complex, using a portable electric saw to construct the wooden
framework of a laundry building. Electricity to operate portable power tools was
supplied by a temporary service pole 50 feet away. The pole had not been
inspected by the city and was not in compliance with code requirements (it was
not grounded). The victim used two extension cords to supply power: a
homemade cord plugged into an ungrounded receptacle on the pole, and a ULapproved cord extending from the homemade cord to the saw. The accident
site was wet; also, humidity was high and the victim was sweating. Reportedly,
he had been shocked throughout the morning and had replaced one of the
extension cords in an effort to eliminate the shocks. The source of the shocks - the saw -- was not replaced. As the victim climbed down a makeshift ladder,
he shifted the saw from his right hand to his left, and was shocked. This caused
him to fall from the ladder and land in a puddle of water, still holding the saw.
Apparently, his hand contracted and he was "locked" to the saw. A co-worker
disconnected the power cord to the saw, too late to save the victim.
Equipment Not Used in Prescribed Manner
If electrical equipment is used in ways for which it was not designed, you can no
longer depend on safety features built in by the manufacturer. This may damage your
equipment and cause employee injuries.
Common Examples of Misused Equipment
• Using multi-receptacle boxes designed to be mounted by fitting them with a
power cord and placing them on the floor
• Fabricating extension cords with ROMEX(r) wire
• Using equipment outdoors that is labeled for use only in dry, indoor locations
• Attaching ungrounded, two-prong adapter plugs to three-prong cords and tools
• Using circuit breakers or fuses with the wrong rating for overcurrent protection;
e.g. using a 30-amp breaker in a system with 15- or 20-amp receptacles
(Protection is lost because it will not trip when the system's load has been
exceeded.)
• Using modified cords or tools; e.g., removing ground prongs, face plates,
insulation, etc.
• Using cords or tools with worn insulation or exposed wires
Sample Incidents
Damaged Extension Cord Leaves Arc Welder Ungrounded
A 29-year-old welder attempted to connect a portable arc welder to an electrical
outlet using an extension cord. The power switch on the welder was already in the
"on" position, and the female end of the extension cord, which was spring-loaded,
had apparently been dropped and broken. As a result, the ground prong of the
welder plug did not insert into the ground terminal of the cord, so that as soon as
a connection was made, the outside metal case of the welder became energized,
electrocuting the victim. An examination revealed that the spring, cover plate, and
part of the melamine casing were missing from the face of the female connector
(the spring and some melamine fragments were found at the accident site). The
victim was totally deaf in one ear and suffered diminished hearing in the other. He
may have dropped the extension cord at the site and not heard the connector
break.
Handling Damaged Extension Cord When Energized
A 19-year-old construction laborer was working with his foreman and another
laborer to construct a waterfront bulkhead for a lakeside residence. Electricity for
power tools was supplied from an exterior 120-volt, grounded AC receptacle
located at the back of the residence. On the day of the incident, the victim
plugged in a damaged extension cord and laid it out toward the bulkhead. There
were no eyewitnesses to the accident, but evidence suggests that while the victim
was handling the damaged and energized extension cord, he provided a "path to
ground" and was electrocuted. The victim collapsed into the lake and sank 4-1/2
feet to the bottom.
Electrical Equipment in Poor Condition
An 18-year-old worker at a construction site was electrocuted when he touched a
light fixture while descending from a scaffold for his afternoon break. The source
of the electricity was apparently a short in a receptacle, but examination revealed
that the electrical equipment used by the contractor was in such poor condition
that it was impossible to make a certain determination of the source of the short.
Extension cords had poor splices, no grounds, and reversed polarity. One hand
drill was not grounded, and the other had no safety plate. Out of several possible
scenarios, the most likely was contact between the exposed wires of an extension
cord and a screw that protruded from the receptacle, which had its faceplate
removed. The light fixture, which served as a ground, was known to be faulty for
at least five months before the incident.
Improper Modification of Plugs
An employee was texturing a wall using an air compressor. The plug of the
compressor and an extension cord had been modified to fit a wall outlet for a
common household clothes dryer (220 V). While attempting to unplug the
compressor from the extension cord, the employee was fatally shocked. The
modification of the plug was not an intended use or prescribed by the
manufacturer.
Improper Use of Extension and Flexible Cords
The normal wear and tear on extension and flexible cords at your site can loosen or
expose wires, creating hazardous conditions. Cords that are not three-wire type, not
designed for hard usage, or that have been modified increase your risk of contacting
electrical current.
Sample Incidents
Flexible Cord Not Three-Wire, Hard Service Variety
A worker received a fatal shock when he was cutting drywall with a metal
casing router. The router's three-wire power cord was spliced to a two-wire
cord and plug set which was not rated for hard service. A fault occurred, and
with no grounding and no GFCI protection, the worker was electrocuted.
No Strain Relief
A worker was operating a 3/4" electric chisel when an electrical fault occurred
in the casing of the tool, causing him to be fatally electrocuted. An OSHA
inspection revealed that the tool's original power cord had been replaced with a
flat cord, which was not designated for hard service, and that strain relief was
not provided at the point where the cord entered the tool. Additionally, the
ground prong was missing and there was no GFCI protection.
Topic Summary
Please take a moment to review these major points before you continue with the next
topic.
• Overhead power lines are uninsulated and can carry tens of thousands of volts,
making them extremely dangerous to employees who work in their vicinity.
Using tools and equipment that can contact power lines increases the risk.
• If the power supply to the electrical equipment at your site is not grounded or
the path has been broken, fault current may travel through a worker's body,
causing electrical burns or death.
• If electrical equipment is used in ways for which it is not designed, you can no
longer depend on safety features built in by the manufacturer. This may
damage your equipment and cause employee injuries.
• The normal wear and tear on extension and flexible cords at your site can
loosen or expose wires, creating hazardous conditions. Cords that are not
three-wire type, not designed for hard usage, or that have been modified
increase your risk of contacting electrical current.
Topic 4: OSHA Requirements
Fall protection, scaffold, steel erection, hazard communication, lockout/tagout and
confined spaces are normally thought of first when discussing occupational health and
safety issues, while electrical safety often goes overlooked. OSHA, however, has
dedicated a large section of the Code of Federal Regulations to electrical safety.
Electrical safety must be a critical part of your company's safety and health program.
This topic introduces those OSHA requirements. Note that the OSHA standard is very
comprehensive. Only some of the major topics and brief summaries of these
requirements are included in this topic. Upon completing this topic, you will be able
to:
• Describe the installation safety requirements
• State safety-related work practices
• Describe safety-related maintenance and environmental considerations
• Describe safety requirements for special equipment
NEC and OSHA Standards
With the ever-expanding use of electricity, the need was recognized for a national
standard to regulate electrical installations nationwide. The National Electrical Code
(NEC) came into being in 1897. It is the electrical standard for the United States and
other foreign countries, including Mexico.
Experts in electrical safety traditionally have looked toward this widely used NEC for
help in the practical safeguarding of persons from these hazards. The Occupational
Safety and Health Administration (OSHA) recognized the important role of the NEC in
defining basic requirements for safety in electrical installations by including the entire
1971 NEC by reference in the Construction Safety and Health Standards.
The NEC provisions directly related to employee safety are included in the body of the
standard itself, making it unnecessary to continue the adoption by reference of the
NEC.
Installation Safety Requirements
This section contains installation safety requirements for electrical equipment and
installations used to provide electric power and light at the job site. The requirements
apply to installations, both temporary and permanent, used on the job site, but they
do not apply to existing permanent installations that were in place before the
construction activity commenced.
Key Point: The electrical conductors and equipment used by the employer must be
approved.
The structure of this topic is as follows:
• Installation Safety Requirements
o Examination and Installation Equipment
o Guarding
o Overcurrent Protection
o Grounding of Equipment Connected by Cord and Plug
• Safety-Related Work Practices
• Safety-Related Maintenance and Environmental Considerations
• Safety Requirements for Special Equipment
• Other Requirements
• OSHA Requirements on Wiring Methods and Equipment for General Use
Examination and Installation of Equipment
Examination of Equipment
The employer must ensure that electrical equipment is free from recognized hazards
that are likely to cause death or serious physical harm to employees.
Safety of equipment should be determined by the following:
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•
Suitability for installation and use in conformity with the provisions of the
standard. Suitability of equipment for an identified purpose may be evidenced
by a listing, by labeling, or by certification for that identified purpose.
Mechanical strength and durability. For parts designed to enclose and protect
other equipment, this includes the adequacy of the protection thus provided.
Electrical insulation
Heating effects under conditions of use
Arcing effects
Classification by type, size, voltage, current capacity, and specific use
Other factors that contribute to the practical safeguarding of employees who
use or are likely to come in contact with the equipment
Installation of Equipment
Listed or labeled equipment should be used or installed in accordance with any
instructions included in the listing or labeling.
Guarding
Live parts of electric equipment operating at 50 volts or more must be guarded
against accidental contact.
Guarding of live parts must be accomplished as follows:
• Location in a cabinet, room, vault, or similar enclosure accessible only to
qualified persons
• Use of permanent, substantial partitions or screens to exclude unqualified
persons
• Location on a suitable balcony, gallery, or platform elevated and arranged to
exclude unqualified persons
• Elevation of eight feet or more above the floor
Entrance to rooms and other guarded locations containing exposed live parts must be
marked with conspicuous warning signs forbidding unqualified persons to enter.
Electric installations that are over 600 volts and that are open to unqualified persons
must be made with metal-enclosed equipment or enclosed in a vault or area
controlled by a lock. In addition, equipment must be marked with appropriate caution
signs.
Overcurrent Protection
Basically, overcurrent protections are circuit breakers, fuses, and so on. The following
requirements apply to overcurrent protection of circuits rated 600 volts, nominal, or
less.
• Conductors and equipment must be protected from overcurrent in accordance
with their ability to safely conduct current, and the conductors must have
sufficient current-carrying capacity to carry the load.
• Overcurrent devices must not interrupt the continuity of the grounded
conductor unless all conductors of the circuit are opened simultaneously,
except for motor-running overload protection.
• Overcurrent devices must be readily accessible and not located where they
could create an employee safety hazard by being exposed to physical damage
or located in the vicinity of easily ignitable material.
• Fuses and circuit breakers must be so located or shielded that employees will
not be burned or otherwise injured by their operation (e.g., arcing).
Grounding of Equipment Connected by Cord and Plug
Exposed noncurrent-carrying metal parts of cord- and plug-connected equipment that
may become energized must be grounded in the following situations:
•
•
•
When in a hazardous (classified) location
When operated at over 150 volts to ground, except for guarded motors and
metal frames of electrically heated appliances if the appliance frames are
permanently and effectively insulated from ground
When one of the types of equipment listed below (See Item 6 for exemption.)
1. Hand-held motor-operated tools.
2. Cord- and plug-connected equipment used in damp or wet locations or
by employees standing on the ground or on metal floors or working
inside metal tanks or boilers
3. Portable and mobile X-ray and associated equipment
4. Tools likely to be used in wet and/or conductive locations
5. Portable hand lamps
6. Exemption: Tools likely to be used in wet and/or conductive locations
need not be grounded if supplied through an isolating transformer with
an ungrounded secondary of not over 50 volts, or if they are protected
by a double insulation system
Safety-Related Work Practices
Safety-related work practices prevent electrical shock or similar injuries by keeping
workers away from energized equipment or circuits.
Passageways and Open Spaces
The employer must provide barriers or other means of guarding to ensure that
workspace for electrical equipment will not be used as a passageway during the time
when energized parts of electrical equipment are exposed. Walkways and similar
working spaces must be kept clear of electric cords.
Lockout and Tagging of Circuits
Tags must be placed on controls that are to be deactivated during the course of work
on energized or de-energized equipment or circuits. Equipment or circuits that are deenergized must be rendered inoperative and have tags attached at all points where
such equipment or circuits can be energized.
What needs to be done before an unqualified person can work on or near energized
equipment?
Live parts must be de-energized before an unqualified person can work on or near
them.
In order to de-energize, the electrical energy source(s) must be disconnected from
the equipment. Merely using the controls to shut down the equipment (i.e., push
buttons, switches, or interlocks) does not qualify as de-energizing equipment or
circuits - the entire unit must be properly disconnected.
After the equipment has the electrical power disconnected, a qualified person then
verifies that the equipment is de-energized, doing so first by operating the controls,
verifying that the equipment will not restart, and second, by using test equipment to
monitor the electrical parts to which employees will be exposed, verifying that they
too are de-energized.
As stated in the standard, if the circuit is over 600V the test equipment must be
checked for proper operation before and immediately after the verification test. (Test
equipment should be checked before and after whatever the voltage to ensure
readings are accurate.) If these procedures are not completed, the equipment must
still be considered "energized." After de-energizing takes place, you may then follow
the remaining procedures as required by your facility's lockout/tagout program.
If exposed live parts are not de-energized (due to increased hazard or infeasibility),
additional safety-related work practices must be used. Only qualified persons are
allowed to work on electrical equipment that has not been de-energized. In addition,
qualified personnel must be familiar with special precautionary techniques, personal
protective equipment, insulating materials, and insulated tools.
Work practices needed for protection against electrical hazards:
• Maintain a ten-foot-minimum clearance from overhead power lines.
• Use barriers or other forms of guarding when live parts of electric equipment
and circuits are exposed.
• Maintain electric equipment in good condition.
• Lock out and tag electric circuits that are to be de-energized.
Safety-Related Maintenance and Environmental Considerations
Maintenance of Equipment
The employer must ensure that all wiring components and utilization equipment in
hazardous locations is maintained in a dust-tight, dust-ignition-proof, or explosionproof condition without loose or missing screws, gaskets, threaded connections, seals,
or other impairments to a tight condition.
Environmental Deterioration of Equipment
Unless identified for use in the operating environment, no conductors or equipment
can be located:
• In damp or wet locations
• Where exposed to gases, fumes, vapors, liquids, or other agents having a
deteriorating effect on the conductors or equipment
• Where exposed to excessive temperatures
•
Control equipment, utilization equipment, and busways approved for use in dry
locations only must be protected against damage from the weather during
building construction.
For protection against corrosion, metal raceways, cable armor, boxes, cable
sheathing, cabinets, elbows, couplings, fittings, supports, and support hardware must
be of materials appropriate for the environment in which they are installed.
Safety Requirements for Special Equipment
Batteries
Batteries of the unsealed type must be located in enclosures with outside vents or in
well-ventilated rooms arranged to prevent the escape of fumes, gases, or electrolyte
spray into other areas. Other provisions include the following:
• Ventilation - to ensure diffusion of the gases from the battery and to prevent
the accumulation of an explosive mixture
• Racks and trays - treated to make them resistant to the electrolyte
• Floors - acid-resistant construction unless protected from acid accumulations
• Face shields, aprons, and rubber gloves - for workers handling acids or
batteries
• Facilities for quick drenching of the eyes and body - within 25 feet of batteryhandling areas
• Facilities - for flushing and neutralizing spilled electrolytes and for fire
protection
Battery Charging
Battery charging installations must be located in areas designated for that purpose.
When batteries are being charged, vent caps must be maintained in functioning
condition and kept in place to avoid electrolyte spray. Also, charging apparatus must
be protected from damage by trucks.
Other Requirements
PRE-PLANNING
Survey your job site to find overhead power lines, poles, and guy wires. Look for
power lines that may be hidden by trees or buildings. Conditions can change easily,
so check the site daily.
ONE CALL
Call your underground utility locator service before you move earth in any way. The
locator will arrange to mark the underground power lines and other utilities so you
can keep a safe distance from them.
CLEARANCE
Use tape, signs, or barricades to help keep yourself, others, and your equipment a
safe distance from overhead power lines.
Federal law requires at least ten feet of clearance from high-voltage power lines.
Your state or local laws may be even more restrictive.
SPOTTERS
As the equipment operator, it's difficult to judge the distance from your equipment to
overhead power lines. Plus, lines may become hard to see in certain lighting or
weather conditions.
A spotter on the ground has a much better view. Work with a spotter whose only
responsibility is to keep you and your equipment a safe distance from overhead
power lines and other hazards.
TAG LINES
If a crane or other equipment hits an overhead power line, electricity can travel
through the tag line and through you.
Don't try to do double duty by guiding a load and spotting. Rely on a designated
spotter to help keep you clear of power lines.
Topic Summary
Please take a moment to review these key points before you continue with the next
topic.
• The employer must ensure that electrical equipment is free from recognized
hazards that are likely to cause death or serious physical harm to employees.
• Listed or labeled equipment should be used or installed in accordance with any
instructions included in the listing or labeling.
• Live parts of electric equipment operating at 50 volts or more must be guarded
against accidental contact.
• Overcurrent devices must be readily accessible and not located where they
could create an employee safety hazard.
• Exposed non-current-carrying metal parts of cord- and plug-connected
equipment that may become energized must be grounded in most situations.
• The employer must provide barriers or other means of guarding to ensure that
a workspace for electrical equipment will not be used as a passageway during
the time when energized parts of electrical equipment are exposed.
• Tags must be placed on controls that are to be deactivated during the course of
work on energized or de-energized equipment or circuits.
• The employer must ensure that all wiring components and utilization
equipment in hazardous locations are maintained in a dust-tight, dust-ignition-
•
•
proof, or explosion-proof condition without loose or missing screws, gaskets,
threaded connections, seals, or other impairments to a tight condition.
Batteries of the unsealed type must be located in enclosures with outside vents
or in well-ventilated rooms arranged to prevent the escape of fumes, gases, or
electrolyte spray into other areas.
Battery-charging installations must be located in areas designated for that
purpose.
Lesson Summary
This lesson contained information and instruction about electricity. By completing this
lesson, you should have the knowledge to discuss the following topics. Take a
moment to see if you can do the following:
• Explain how electricity works and define the fundamental concepts of electricity
• Describe the effects of electricity on the human body, including shocks, burns,
and other injuries
• Recognize common electrical hazards
• State OSHA requirements on installation safety concerning examination and
installation of equipment, guarding, overcurrent protection, and grounding
• State OSHA requirements for electricity, including safety-related work
practices, safety-related maintenance and environmental considerations, and
safety requirements for special equipment
Electrical Part II
Lesson Overview
Welcome to the "Electrical Part II" lesson of the Turner OSHA Certification course.
This lesson examines the controls for electrical hazards. In this lesson, you will learn
about effective controls for common electrical hazards and OSHA requirements on
wiring methods and equipment for general use. You will also learn about ground-fault
circuit interrupters (GFCI) and detailed grounding requirements.
Upon
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•
completing this lesson, you will be able to:
Identify the effective controls for common electrical hazards
Describe two means of preventing electrical injuries: insulation and grounding
Define ground-fault circuit interrupter (GFCI)
Explain the importance of testing a GFCI and how to test it
Why Learn This Lesson?
According to the Bureau of Labor Statistics, electrocutions dropped below 300 for the
first time in five years in 1999. Unfortunately, construction workers still represent 45
percent of job site electrocution deaths.
Certain types of jobs also put some at a higher risk: supervisors, electricians,
painters, machine operators, and welders, just to name a few. No matter what your
job is or the type of job site at which you work, electrical hazards must be evaluated.
By developing and implementing a strong, well-defined electrical program, you can
minimize the risks of electrical hazards.
The information in this lesson will help you control and manage effectively the
hazards associated with working with and around temporary and permanent
electricity.
Topic 1: Electrical Hazard Controls
This topic addresses controls for common electrical hazards. Upon completing this
lesson, you will be able to:
• Determine the effective control measures over most frequently cited serious
violations
• Describe how to avoid the following common electrical hazards:
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Contact with power lines
Path to ground missing or disconnected
Equipment not used in manner prescribed
Improper use of extension and flexible cords
Effective Controls to Common Electrical Hazards
What effective control measures can be used to control the violation of the
requirements listed below?
•
Electric equipment must be approved by an OSHA-accepted laboratory or
agency.
Make sure that electric equipment is listed or labeled by an agency or testing
laboratory acceptable to OSHA.
•
Electric equipment must be free from recognized hazards and used in
accordance with manufacturers' and approval agency instructions.
Use electric equipment in accordance with the manufacturer's instructions.
Install electric equipment with exposed live parts inside approved enclosures,
or install exposed live parts in such a manner that unqualified employees
cannot readily gain access to them (for example, by installation at a height of
eight feet or more above the floor).
•
Live parts of electric equipment operating at more than 50 volts must be
guarded from contact by an approved enclosure or by other approved means.
Make sure that all non-double-insulated electric equipment is equipped with a
grounding conductor. Maintain the equipment grounding conductor in good,
operable condition.
•
Employers must provide either ground-fault circuit interrupters or an assured
equipment grounding conductor program.
Provide either ground-fault circuit interrupters or an assured equipment
grounding conductor program (which includes the regular testing of all
equipment grounding conductors) to protect employees from ground faults.
Effective Controls to Common Electrical Hazards Cont.
•
Extension cord sets used with portable tools and appliances must be of the
three-wire, grounding type, and flexible cords must be designed for hard or
extra-hard usage.
Use only three-wire extension cords sets, which provide an equipment
grounding conductor. (This applies regardless of whether they are used "only"
with double-insulated tools and equipment.) Use flexible cords and cables that
are marked with one of the following types: S, SC, SCE, SCT, SE, SEO, SEOO,
SJ, SJE, SJEO, SJEOO, SJO, SJT, SJTO, SJTOO, SO, SOO, ST, STO, STOO, G,
PPE, or W.
•
Flexible cords must be provided with strain relief.
Provide strain relief where flexible cords are connected to devices and fittings
to prevent pull from being applied directly to joints or terminal screws.
•
The employer must determine the location of electric circuits that might be
contacted during the course of work and must implement measures to protect
employees from accidental contact.
Determine, by direct observation, inquiry, or the use of instruments, whether
energized electric circuits are present in a work area where they might be
contacted by employees. De-energize and ground the circuits or guard them,
or use insulation to protect employees. Inform employees of the presence and
location of these circuits.
•
Worn or frayed electric cords and cables may not be used.
Inspect flexible cords for damage and discard or repair any that are worn or
frayed or that have damaged insulation.
Controls for Contact With Power Lines
Overhead and buried power lines at your site are especially hazardous, because they
carry extremely high voltage. Fatal electrocution is the main risk, but burns and falls
from elevation are also hazards. Using tools and equipment that can contact power
lines increases the risk.
How to avoid the hazard:
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Look for overhead power lines and buried power line indicators. Post warning
signs.
Contact utilities for buried power line locations.
Stay at least ten feet away from overhead power lines.
Unless you know otherwise, assume that overhead lines are energized.
De-energize and ground lines when working near them. Other protective
measures include guarding or insulating the lines.
Use non-conductive wood or fiberglass ladders when working near power lines.
If you are operating heavy equipment that contacts a power line, take these steps:
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If you can do so safely, move the equipment away from the line.
Stay on the equipment until rescue workers say it is safe to get out.
Warn others to stay away. Anyone on the ground who touches the equipment
may be injured or killed.
Have someone call 911 and the local electrical utility immediately.
If fire or other danger forces you out or off of the equipment, jump clear
without touching the ground and the equipment at the same time.
Take small shuffling steps, always keeping both feet on the ground, or hop
away on two feet, keeping your feet together.
Controls for Path to Ground Missing or Disconnected
If the power supply to the electrical equipment at your site is not grounded or the
path has been broken, electrical current may travel through a worker's body, causing
electrical burns or death. Even when the power system is properly grounded,
electrical equipment can change from safe to hazardous instantly because of extreme
conditions and rough treatment.
How to avoid the hazard:
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Ground all power supply systems, electrical circuits, and electrical equipment.
Frequently inspect electrical systems to ensure that the path to ground is
continuous.
Visually inspect all electrical equipment before use. Take any defective
equipment out of service.
Do not remove ground prongs from cord- and plug-connected equipment or
extension cords.
Use double-insulated tools.
Ground all exposed metal parts of equipment.
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Ground metal parts of the following non-electrical equipment, as specified by
the OSHA standard:
o Frames and tracks of electrically operated cranes
o Frames of non-electrically driven elevator cars to which electric
conductors are attached
o Hand-operated metal shifting ropes or cables of electric elevators
o Metal partitions, grill work, and similar metal enclosures around
equipment of over 1kV between conductors
Controls for Equipment Not Used in Prescribed Manner
If electrical equipment is used in ways for which it is not designed, you can no longer
depend on safety features built in by the manufacturer. This may damage your
equipment and cause employee injuries.
How to avoid the hazard:
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Use only equipment that is approved to meet OSHA standards.
Use all equipment according to the manufacturer's instructions.
Do not modify cords or use them incorrectly.
Be sure equipment that has been shop-fabricated or altered is in compliance.
Controls for Improper Use of Extension and Flexible Cords
The normal wear and tear on extension and flexible cords at your site can loosen or
expose wires, creating hazardous conditions. Cords that are not the three-wire type,
are not designed for hard usage, or that have been modified increase your risk of
contacting electrical current.
How to avoid the hazard:
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Use factory-assembled cord sets.
Inspect cords before each use.
Be sure plug and receptacle have proper mating configuration.
Don't use nails, staples, screws, etc., to attach or fasten a cord or plug.
Two-conductor cords are illegal.
Use only extension cords that are the three-wire type.
Use only extension cords that are marked with a designation code for hard or
extra-hard usage.
Use only cords, connection devices, and fittings that are equipped with strain
relief.
Ensure enough slack to prevent strain on plug or receptacle.
A plug receptacle should have at least eight ounces of contact tension.
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Cords should be kept clean and free of kinks and insulation breaks.
Cords crossing vehicular or personnel passageways should be protected,
posted, and used temporarily or in an emergency.
Cords should be of continuous length and without splices.
Remove cords from receptacles by pulling on the plugs, not the cords.
Continually audit cords on site. Any cords found not to be marked for hard or
extra-hard use, or which have been modified, must be taken out of service
immediately.
Topic Summary
Please take a moment to review these major points before you continue with the next
topic.
• Maintain at least ten feet clearance from overhead power lines.
• Make sure all equipment is properly grounded.
• Use all equipment according to the manufacturer's instructions.
• Inspect cords before each use.
Topic 2: Insulation and Grounding
This topic addresses two recognized means of preventing injury during electrical
equipment operation: insulation and grounding. Upon completing this topic, you will
be able to:
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Define the class and type of insulated equipment
Define grounding, including system grounding and equipment grounding
Describe the assured equipment grounding conductor program
Determine if equipment needs to be grounded given a situation
Two Means of Preventing Electrical Injuries
Insulation and grounding are two recognized means of preventing injury during
electrical equipment operation.
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Insulations: Conductor insulation may be provided by placing nonconductive
material such as plastic around the conductor.
Grounding: Grounding may be achieved through the use of a direct connection
to a known ground, such as a metal cold-water pipe.
Insulated Tools
Insulated tools must be used when a qualified person is working on or near exposed
energized live conductors. Only insulated tools that comply with the International
Electrotechnical Commission Standard 900 (IEC 900) and marked with the
international 1000V rating symbol should be used. Not all tools with a plastic coating
or plastic handles provide protection from electrical shock. That's why it's important
to inspect your tools before performing electrical work. Also, if insulated tools become
damaged or worn, the tool must be removed from service and destroyed.
In addition to wearing insulated rubber gloves, protector gloves, usually made of
leather, are to be worn over the rubber gloves. There are two exceptions to this rule.
Protector gloves are not required for either:
• Class 0 gloves where high finger dexterity is required
• In a case when a person uses a glove one class higher than required in a
situation where there's minimal chance of damage (The drawback of doing this
is that the insulated glove may not be used again at that higher voltage rate
until it has been retested and certified.)
Electrical Protective Equipment
Electrical protective equipment, also known as insulated equipment, includes items
such as insulated blankets, matting, covers, line hose, gloves, and sleeves. Blankets,
gloves, and sleeves are clearly marked with class and type.
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The class refers to the maximum use voltage. Insulating equipment must not
exceed maximum use voltages.
The type marking refers to its ozone resistance. Type I is not ozone resistant;
Type II is ozone resistant.
Insulated equipment must be inspected before each day's use and immediately
following an incident that may have caused damage. When insulated equipment is
removed from service, it may not be used again until it has been retested and
certified. All electrically-insulated equipment must also be retested and certified
periodically. The retesting period depends on each type of equipment
With what kind of defects should insulated equipment to be removed from service?
Insulated equipment must not be used if it is found to have any of the following
defects:
• Holes, tears, punctures, cuts
• Ozone cutting or checking
• Embedded foreign object(s)
• Swelling, softening, hardening, loss of elasticity, or stickiness
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Any other defect
Commonly Asked Questions
Q. Does insulated equipment need to be approved or certified?
A. Insulated equipment must be certified by the manufacturer to be suitable-given
the proper usage-for the specified conditions to which they are exposed. The
certificate identifies the equipment and the date it was tested.
Q.
Is there an expiration date for insulated equipment after which it must be
destroyed?
A.
No. As long as the insulated equipment is in a safe, reliable condition and
retested periodically as required by 29 CFR 1910.137, it may continue to be used.
What Is Grounding?
The term ground refers to a conductive body, usually the earth. "Grounding" a tool or
electrical system means intentionally creating a low-resistance path to the earth.
When properly done, current from a short or from lightning follows this path, thus
preventing the buildup of voltages that would otherwise result in electrical shock,
injury, or even death.
There are two kinds of grounds (both grounds are required by the OSHA construction
standard):
• System or service ground: In this type of ground, a wire called "the neutral
conductor" is grounded at the transformer, and again at the service entrance to
the building. This is primarily designed to protect machines, tools, and
insulation against damage.
• Equipment ground: This is intended to offer enhanced protection to the workers
themselves. If a malfunction causes the metal frame of a tool to become
energized, the equipment ground provides another path for the current to flow
through the tool to the ground.
Summary of Grounding Requirements
The following is a summary of OSHA's grounding requirements.
• Ground all electrical systems.
• The path to ground from circuits, equipment, and enclosures must be
permanent and continuous.
• Ground all supports and enclosures for conductors.
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Ground all metal enclosures for service equipment.
Ground all exposed, non-current-carrying metal parts of fixed equipment.
Ground exposed, non-current-carrying metal parts of tools and equipment
connected by cord and plug.
Ground the metal parts of the following non-electrical equipment:
o Frames and tracks of electrically operated cranes
o Frames of non-electrically driven elevator cars to which electric
conductors are attached
o Hand-operated metal shifting ropes or cables of electric elevators
o Metal partitions, grill work, and similar metal enclosures around
equipment of over 1kV between conductors
Assured Equipment Grounding Conductor Program
The assured equipment grounding conductor program covers all cord sets,
receptacles which are not a part of the permanent wiring of the building or structure,
and equipment connected by cord and plug which is used (or is available for use) by
employees.
OSHA requires that a written description of the employer's assured equipment
grounding conductor program, including the specific procedures adopted, be kept at
the job site. This program should outline the employer's specific procedures for the
required equipment inspections, tests, and test schedule.
The required tests must be recorded, and the record maintained until replaced by a
more-current record. The written program description and the recorded tests must be
made available, at the job site, to OSHA and to any affected employee upon request.
The employer is required to designate one or more competent persons to implement
the program.
Electrical equipment noted in the assured equipment grounding conductor program
must be inspected visually for damage or defects before each day's use. Any
damaged or defective equipment must not be used by the employee until repaired.
What tests does OSHA require?
Two tests are required by OSHA:
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One is a continuity test to ensure that the equipment grounding conductor is
electrically continuous. It must be performed on all cord sets, receptacles which
are not part of the permanent wiring of the building or structure, and on cordand plug-connected equipment which is required to be grounded. This test may
be performed using a simple continuity tester, such as a lamp and battery, a
bell and battery, an ohmmeter, or a receptacle tester.
•
The other test must be performed on receptacles and plugs to ensure that the
equipment grounding conductor is connected to its proper terminal. This test
can be performed with the same equipment used in the first test.
These tests are required before first use, after any repairs, after damage is
suspected to have occurred, and at three-month intervals. Cord sets and
receptacles that essentially are fixed and not exposed to damage must be tested
at regular intervals not to exceed six months. Any equipment that fails the
required tests shall not be made available to or be used by employees.
Other OSHA Requirements for Grounding
The following is a list of additional OSHA requirements for grounding.
Supports and enclosures for conductors
Metal cable trays, metal raceways, and metal enclosures for conductors must be
grounded, with these exceptions:
• Metal enclosures such as sleeves that are used to protect cable assemblies
from physical damage need not be grounded.
• Metal enclosures for conductors added to existing installations of open wire,
knob-and-tube wiring, and nonmetallic sheathed cable need not be grounded if
all of the following conditions are met:
o Runs are less than 25 feet
o Enclosures are free from probable contact with ground, grounded metal,
metal laths, or other conductive materials
o Enclosures are guarded against employee contact
Service equipment enclosures
Metal enclosures for service equipment must be grounded.
Exposed non-current-carrying metal parts of fixed equipment which may become
energized must be grounded under any of the following conditions:
• If within eight feet vertically or five feet horizontally of ground or grounded
metal objects and subject to employee contact
• If located in a wet or damp location and subject to employee contact
• If in electrical contact with metal
• If in a hazardous (classified) location
• If supplied by a metal-clad, metal-sheathed, or grounded metal raceway wiring
method
• If equipment operates with any terminal at over 150 volts to ground; however,
the following need not be grounded:
o Enclosures for switches or circuit breakers used for other than service
equipment and accessible to qualified persons only
o Metal frames of electrically heated appliances which are permanently
and effectively insulated from ground
o
The cases of distribution apparatus such as transformers and capacitors
mounted on wooden poles at a height exceeding eight feet above ground
or grade level
Exposed non-current-carrying metal parts of cord- and plug-connected equipment
which may become energized must be grounded:
• If in a hazardous (classified) location
• If operated at over 150 volts to ground, except for guarded motors and metal
frames of electrically heated appliances if the appliance frames are
permanently and effectively insulated from ground
• If the equipment is one of the types listed below:
o Hand-held motor-operated tools
o Cord- and plug-connected equipment used in damp or wet locations or
by employees standing on the ground or on metal floors or working
inside of metal tanks or boilers
o Portable and mobile X-ray and associated equipment
o Tools likely to be used in wet and/or conductive locations
o Portable hand lamps
Tools likely to be used in wet and/or conductive locations need not be grounded if
supplied through an isolating transformer with an ungrounded secondary of not over
50 volts. Listed or labeled portable tools and appliances protected by a system of
double insulation or its equivalent need not be grounded. If such a system is
employed, the equipment must be marked distinctively to indicate that the tool or
appliance utilizes a system of double insulation.
Nonelectrical equipment
The metal parts of the following nonelectrical equipment must be grounded:
• Frames and tracks of electrically operated cranes
• Frames of non-electrically driven elevator cars to which electric conductors are
attached
• Hand-operated metal shifting ropes or cables of electric elevators, and metal
partitions, grill work, and similar metal enclosures around equipment of over
1kV between conductors
Grounding of systems supplying portable or mobile equipment
Systems supplying portable or mobile high-voltage equipment, other than substations
installed on a temporary basis, must comply with the following:
• Portable and mobile high-voltage equipment must be supplied from a system
having its neutral grounded through an impedance. If a delta-connected high
voltage system is used to supply the equipment, a system neutral must be
derived.
• Exposed non-current-carrying metal parts of portable and mobile equipment
must be connected by an equipment grounding conductor to the point at which
the system neutral impedance is grounded.
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Ground-fault detection and relaying must be provided to automatically deenergize any high-voltage system component that has developed a ground
fault. The continuity of the equipment grounding conductor must be monitored
continuously so as to de-energize the high-voltage feeder to the portable
equipment automatically upon loss of continuity of the equipment grounding
conductor.
The grounding electrode to which the portable or mobile equipment system
neutral impedance is connected must be isolated from and separated in the
ground by at least 20 feet from any other system or equipment grounding
electrode, and there must be no direct connection between the grounding
electrodes, such as buried pipe, fence, or like objects.
All non-current-carrying metal parts of portable equipment and fixed equipment,
including their associated fences, housings, enclosures, and supporting structures,
must be grounded. However, equipment which is guarded by location and isolated
from ground need not be grounded. Additionally, pole-mounted distribution apparatus
at a height exceeding eight feet above ground or grade level need not be grounded.
Topic Summary
Please take a moment to review these key points before you continue with the next
topic.
• Insulated tools must be used when a qualified person is working on or near
exposed energized live conductors.
• Electrical protective equipment, also known as insulated equipment, includes
items such as insulated blankets, matting, covers, line hose, gloves, and
sleeves.
• Insulated equipment must be inspected before each day's use and immediately
following an incident that may have caused damage.
• "Grounding" a tool or electrical system means intentionally creating a lowresistance path to the earth.
• There are two kinds of grounds: system or service ground and equipment
ground. Both are required by the OSHA construction standard.
• Metal cable trays, metal raceways, and metal enclosures for conductors must
be grounded.
• Exposed non-current-carrying metal parts of fixed equipment that may become
energized must be grounded.
• Exposed non-current-carrying metal parts of cord- and plug-connected
equipment that may become energized must be grounded.
• The metal parts of the following non-electrical equipment must be grounded:
o Frames and tracks of electrically operated cranes
o Frames of non-electrically driven elevator cars to which electric
conductors are attached
Hand-operated metal shifting ropes or cables of electric elevators, and
metal partitions, grill work, and similar metal enclosures around
equipment of over 1kV between conductors.
The assured equipment grounding conductor program covers all cord sets,
receptacles which are not a part of the permanent wiring of the building or
structure, and equipment connected by cord and plug which is available for use
(or is used) by employees.
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Topic 3: Ground-Fault Circuit Interrupter (GFCI)
This topic covers ground fault circuit interrupters (GFCI). Upon completing this topic,
you will be able to:
• Define GFCI
• Describe the importance of testing GFCI
• State two important steps to ensure GFCI functions well
Need for GFCIs
Insulation and grounding are two recognized means of preventing injury during
electrical equipment operation. However, there are deficiencies associated with
insulation and grounding.
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For grounding, a break in the grounding system may occur without the user's
knowledge.
For insulation, insulation may be damaged by hard usage on the job or simply
by aging. If this damage causes the conductors to become exposed, the
hazards of shocks, burns, and fire will exist.
The use of a ground-fault circuit interrupter (GFCI) is one method used to overcome
grounding and insulation deficiencies.
What Is a GFCI?
The ground-fault circuit interrupter (GFCI) is a fast-acting circuit breaker that senses
small imbalances in the circuit caused by current leakage to ground and, in a fraction
of a second, shuts off the electricity. The GFCI continually matches the amount of
current going to an electrical device against the amount of current returning from the
device along the electrical path. Whenever the amount "going" differs from the
amount "returning" by approximately 5 milliamps, the GFCI interrupts the electric
power within as little as 1/40 of a second.
If the current flowing in the black (ungrounded) wire is within 5 ((1) milliamperes of
the current flowing in the white (grounded) wire at any given instant, the circuitry
considers the situation normal. All the current is flowing in the normal path. If,
however, the current flow in the two wires differs by more than 5 mA, the GFCI will
quickly open the circuit.
Note: GFCI will not protect the employee from line-to-line contact hazards (such as a
person holding two "hot" wires or a hot and a neutral wire in each hand). It does
provide protection against the most common form of electrical shock hazard -- the
ground fault. It also provides protection against fires, overheating, and destruction of
insulation on wiring.
Sample Incident
Death Due to Lack of Ground-Fault Protection - No GFCI
A journeyman HVAC worker was installing metal ductwork using a double-insulated
drill connected to a drop light cord. Power was supplied through two extension cords
from a nearby residence. The individual's perspiration-soaked clothing/body contacted
bare exposed conductors on one of the cords, causing an electrocution. No GFCIs
were used. Additionally, the ground prongs were missing from the two cords.
Testing GFCIs
We take for granted that our GFCIs are providing protection if we can operate a tool,
hair dryer, or other item through them. Yet this is not always the case. While the
device will allow current to flow through it, the monitoring of the current may not be
taking place.
Built into the device is a metal oxide varistor (MOV) used as a surge suppressor. The
MOV absorbs the voltage surge and converts it into heat. Repeated surges can
degrade the MOV, still allowing current to flow but not providing the protection
required. Voltage surges such as lightning strikes in the area can cause a surge, as
can utility company switching.
Some parts of the country are more susceptible to lightning strikes than others. This
is a primary cause of GFCI failures. According to an inspecting survey done by the
American Society of Home Inspectors, in parts of Florida, up to 58 percent of the
GFCI circuit breakers and 33 percent of the receptacles were defective.
The Bottom Line for Safety
If you follow just these two steps, whether at home or at work, you can help ensure
that your GFCIs function as life-protecting devices.
1. Test them monthly as required.
2. When a GFCI trips, reset and then trip it using either a GFCI tester or test
button on the device. Reset and use the circuit!
In the event a GFCI trips out, is reset, and power restored, you should go a step
further and test the GFCI. The test is a very simple procedure where you press the
test button on the device to ensure that it does trip open to break the circuit. This
test button creates a difference of 5 milliamperes between the hot and neutral
through a resistor built into the device. If the device will not trip open, or if it trips
and current continues to flow, the device is defective and must be replaced.
Employers' Responsibility
It is the employer's responsibility to provide either:
• Ground-fault circuit interrupters on construction sites for receptacle outlets in
use that are not part of the permanent wiring of the building or structure
• A scheduled and recorded assured equipment grounding conductor program on
construction sites, covering all cord sets, receptacles which are not part of the
permanent wiring of the building or structure, and equipment connected by
cord and plug which is available for use (or is used) by employees.
Topic Summary
Please take a moment to review these key points before you continue with the next
topic.
• The ground-fault circuit interrupter (GFCI) is a fast-acting circuit breaker that
senses small imbalances in the circuit caused by current leakage to ground
and, in a fraction of a second, shuts off the electricity.
• You can help ensure that your GFCIs function as life-protecting devices by
testing them monthly or as required.
• When a GFCI trips, reset and then trip it using either a GFCI tester or test
buttons on the device. Reset and use the circuit!
• It is the employer's responsibility to provide GFCIs on construction sites for
receptacle outlets in use that are not part of the permanent wiring of the
building or structure.
Lesson Summary
This lesson contains information and instruction about electricity. By completing this
lesson, you should have the knowledge to discuss the following topics. Take a
moment to see if you can do the following:
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Identify the effective controls for common electrical hazards
Describe two means of preventing electrical injuries: insulation and grounding
Define ground-fault circuit interrupter (GFCI)
Explain the importance of testing a GFCI and how to test it
Scaffolds
Introduction
Identifying the hazards of working with scaffolds is an important responsibility
of all construction workers. OSHA confirms that employees using scaffolds are
exposed to a significant risk of harm. Specifically, scaffold-related fatalities
account for approximately 9 percent of fatalities in the construction industry.
Lesson Overview
This lesson explains OSHA's requirements for using scaffold systems. You will
learn about the different types and proper use of scaffolds. You also will learn
more about OSHA standards and the general obligations of employers and
employees to meet them. In addition this lesson addresses specific safety
requirements for the many types of scaffolds that are used in the construction
industry. It also will discuss safety requirements for the aerial and scissor lifts.
Upon
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completing this lesson, you will be able to:
Describe the general safety requirements for scaffolds
Identify the different types and components of scaffolds
Implement the proper safety precautions and uses of scaffolds
Define supported, suspended, and special use scaffolds and define aerial
and scissor lifts
State specific safety requirements of various types of supported
scaffolds
Describe specific safety requirements of various types of suspended
scaffolds
Apply specific safety requirements of various types of special use
scaffolds in your work
State specific safety requirements of aerial and scissor lifts
Why Learn This Lesson?
There is little doubt that scaffolding makes a job site more hazardous. Falls,
falling objects, and structural instability are all potential dangers at a scaffold
work site.
Of the 510,000 injuries and illnesses reported in the construction industry, an
estimated 9,750 are related to scaffolds. Similarly, of the estimated 1,000plus occupational fatalities occurring annually among construction employees,
at least 79 are associated with work on scaffolds.
Scaffolding has a wide variety of uses in the construction industry, including
new construction, alteration, routine maintenance, renovation, painting,
repairing, and removal activities. When properly used, scaffold systems offer a
safer and more comfortable working posture compared to leaning over edges,
stretching overhead, or even working from a ladder.
Scaffolding incidents mainly involve worker falls and falling materials.
Equipment failure, incorrect operating procedures for the type of scaffold being
used, and overloading of scaffolds usually cause these incidents.
This lesson will provide you with the specific safety requirements for the many
types of scaffolds used in the construction industry.
Topic 1: Scaffold Requirements
All employers and employees using scaffolds must become familiar with OSHA
specifications.
Who uses scaffolds?
Workers from every trade in the construction industry may work on, below, or
near a scaffold. Erectors and dismantlers, however, are workers whose
principal activity is assembling and disassembling scaffolding before, during,
and after work has been completed.
Although OSHA provides employers with flexibility in the design of scaffolds
and the selection of fall protection, a competent person is required to
supervise these workers. This person has the training, experience, and
authority to take the corrective action necessary to determine the scaffold's
fall protection, integrity, and safety. OSHA recognizes that an employer may
have more than one competent person on the work site to deal with different
aspects of scaffolding.
Note: OSHA recognizes that an employer may have more than one
competent person on the work site to deal with different aspects of
scaffolding.
What is a scaffold?
A scaffold is an elevated, temporary work platform. There are three basic
types of scaffolds: supported, suspended, and forms of manlifts. These types
will be discussed in a separate topic.
When do hazards exist?
Common hazardous scaffold areas are:
• Access
• Collapse
• Electrical
• Falls
• Instability
• Struck-by
Where do you find the safety standards for scaffolds?
The OSHA standards are covered in Subpart L of the OSHA Standards for
Construction. Some of the areas covered in the OSHA safety standards for
scaffolds include:
• Types of scaffolds
• Falling object protection
• Training
• Ladders
• Weather conditions
• Aerial lifts
Scaffold General Requirements
OSHA requires that all employees and employers who work on, under, or near
scaffolding and aerial lifts be protected from hazards. Therefore, workers using
scaffolds in the construction industry must become familiar with these and
other safety requirements for scaffolds. Click each topic to review its safety
standards.
CAPACITY
Each scaffold and scaffold component must be able to support its own weight
and at least four times the maximum intended load that it will be expected to
carry. The scaffold's intended load is required to:
• Not exceed its maximum intended load or capacity rating
• Include all personnel, equipment, and supply loads
• Be less than the rated load but never exceed the rated load unless
approved by an engineer and the manufacturer
• Use a minimum of 1,500 lb-f/in2 construction-grade lumbers when
carried by timber members
PLATFORM CONSTRUCTION
Each platform on a scaffold must be planked and decked as fully as possible,
and the work area should be free of clutter and debris. The platform
construction requirements involve distances and components.
Distances
• The space between the platform and the uprights of the scaffold should
not be more than one inch wide.
• The gap resulting from use of side brackets and an odd-shaped structure
should not exceed nine and half inches.
• Each scaffold platform and walkway must be at least at 18 inches wide.
Components
• The intermixing or modification of scaffold components must be done
under the supervision of a competent person who will determine that the
integrity of the scaffolding is maintained.
• Scaffold components made of dissimilar metals must not be used
together unless a competent person has determined that galvanic action
will not reduce the strength of any component to below the
requirements of OSHA.
SCAFFOLD PLANKING
To meet the safety requirements for planking:
• Scaffold planking must be able to support its own weight and at least
four times the intended load.
• Solid wood, fabricated planks, and fabricated platforms all can be used
as scaffold planking provided the recommendations of the manufacturer
are followed.
ACCESS
Access is required on all scaffolds based on these distances:
• The platform is more than two feet above or below the point of access.
• Direct access to scaffolds is permitted when the scaffold is not more
than 14 inches horizontally and 24 inches vertically from the other
surfaces.
Several types of access are permitted:
• Ladders (portable, hook-on, attachable, and stairway)
• Stair towers
• Ramps and walkways
• Integral prefabricated frames
Note: The use of cross bracing as a means of access is prohibited.
Training
Prior to 1996, it was estimated that more than 70 percent of workers received
only on-the-job scaffold safety training, and 25 percent received no training at
all. Today OSHA requires all employees who work on scaffolds to receive
training in the following areas:
• The nature of any electrical hazards, fall hazards, and falling object
hazards in the work area
• The correct procedures for dealing with electrical hazards and for
erecting, maintaining, and disassembling the fall protection systems and
falling object protection systems
• The proper use of the scaffold and the proper handling of materials on
the scaffold
• The maximum intended load and the load-carrying capacities of the
scaffolds used
Construction can be a safe occupation when workers are aware of the hazards
and an effective safety and health program is used.
Who Will Train?
All employees who work on scaffolds must be trained by a person who is
qualified to recognize the hazards associated with the type of scaffold being
used and to understand the procedures to control or minimize those hazards.
OSHA defines a qualified person as an individual who, by possession of a
recognized degree, certificate, or professional standing, or who by extensive
knowledge, training, and experience, has successfully demonstrated his or her
ability to solve or resolve problems relating to the subject matter, the work, or
the project.
How will I be confident in my selection and use of proper fall arrest systems?
Careless or improper use of the equipment can result in serious injury or
death. Thorough employee training in the selection and use of personal fall
arrest systems is imperative.
Employees must be trained in the safe use of the system. This should include
the following:
• Application limits
• Proper anchoring and tie-off techniques
• Estimation of free fall distance, including determination of deceleration
distance and total fall distance to prevent striking a lower level
• Methods of use
• Inspection and storage of the system
• Manufacturer's recommendation
Any employee involved in the erecting, disassembling, moving, operating,
repairing, maintaining, or inspecting of a scaffold must be trained by a
competent person to recognize any hazards associated with the work in
question.
The training will include the following topics, as applicable:
• The nature of scaffold hazards
• The correct procedures for erecting, disassembling, moving, operating,
repairing, inspecting, and maintaining the type of scaffold in question
• The design criteria, maximum intended load-carrying capacity, and
intended use of the scaffold
• General overview of scaffolding
• Regulations and standards
• Erection/dismantling planning
• PPE and proper procedures
• Fall protection
• Materials handling
• Access
• Working platforms
• Foundations
•
Guys, ties, and braces
Scaffold erectors and dismantlers all should receive the general overview, and,
in addition, specific training for the type of scaffold being erected or
dismantled.
Topic Summary
Please take a moment to review these key points before you continue with the
next topic.
• Each scaffold and scaffold component must be able to support its own
weight and at least four times the maximum intended load that it will be
expected to carry.
• Each platform on a scaffold must be planked and decked as fully as
possible.
• Mixing scaffold components produced by different manufacturers is not
recommended.
• Permitted types of access for scaffolds include ladders, stair towers,
ramps and walkways, and integral prefabricated frames. Cross bracing
for access is prohibited.
• Employees are required to receive training in the correct procedures for
dealing with electrical conditions, fall protection, material use, and load
capacities.
Topic 2: Scaffold Types
While there are many safety requirements developed by the manufacturers of
scaffolds, all employees must be protected from hazards under OSHA
standards. This topic will explain the different types of scaffold systems and
their components so that you can:
• Identify the types, components, and proper use of supported scaffolds
• Identify the types, components, and proper use of suspension scaffolds
Supported Scaffold
Supported scaffolds are platforms that are supported by legs, outrigger
beams, brackets, poles, uprights, posts, frames, or some type of similar rigid
support. The structural members of supported scaffolds must be plumb and
properly braced to prevent swaying and displacement.
Types
There is a variety of support scaffold available to the industry. Here is a short
list of descriptions:
• Frame Scaffold or Fabricated Frame: platform(s) supported on fabricated
end frames with integral posts, horizontal bearers, and intermediate
members
• Manually Propelled Mobile: unpowered, portable, caster or wheelmounted supported scaffold
• Pump Jack: platform supported by vertical poles and movable support
brackets
• Ladder Jack: platform resting on brackets attached to ladders
• Tube and Coupler: platform(s) supported by tubing, erected with
coupling devices connecting uprights, braces, bearers, and runners
• System: Posts with fixed connection points that accept runners, bearers,
and diagonals that can be interconnected at predetermined levels
Tipping
Supported scaffolds with a height-to-base width ratio of more than 4:1 must
be prevented from tipping by using restraint devices, such as guying, tying, or
bracing. When using any of these systems, it is best to follow the
manufacturer's recommendations.
In the absence of the manufacturer requirements, the following placements
should be used:
1. Install guys, ties, or braces at the closest horizontal member to the 4:1
height and repeat vertically with the top restraint no further than the 4:1
height from the top.
2. Vertically - space restraint devices every 20 feet or less for scaffolds less
than three feet wide, and every 26 feet or less for scaffolds more than
three feet wide.
3. Horizontally - space restraint devices at each end and at intervals not to
exceed 30 feet from one end.
Foundations
To prevent collapse or tipping, place all supported scaffold poles, legs, posts,
frames, and uprights on base plates and mud sills or other adequate firm
foundation. Unstable objects cannot be used to support scaffolds or platform
units. A concrete slab would be considered a firm foundation; therefore, mud
sills would not be necessary.
Other Equipment
1. Front-end loaders and similar pieces of equipment can be used to
support scaffold platforms only when the manufacturer specifically
designs the equipment for this purpose.
2. Forklifts may be used only if the entire platform is attached to the forks
and the forklift does not move horizontally when workers are on the
platform. "Attached" does not mean merely placing the platform on the
forks. A positive means of attachment, such as bolting, must be present.
3. When either forklifts or front-end loaders are used to support scaffolds,
all other requirements of the scaffolding standards (capacity,
construction, access, use and fall protection, etc.) must be met.
NOTE: These types of equipment are not considered aerial lifts unless they
are designed and used primarily to position personnel and meet all other
requirements for aerial lifts.
Erection/Dismantling
During scaffold and erection and dismantling operations employers must
determine where safe access and fall protection can be provided. The following
requirements must be met:
• The employer has the responsibility to evaluate whether providing
access for employees is feasible and safer (i.e., does not create a
greater hazard).
• A competent person who has the knowledge and experience necessary
must make the appropriate determination.
• Hook-on or attachable ladders must be installed as soon as scaffold
erection has progressed to a point that permits safe installation and use.
• When erecting or dismantling frame scaffolds, the end frames can be
used for climbing if they are more than 22 inches apart and provide
good hand hold and foot space. Cross braces, however, cannot be used.
Suspension Scaffolds
A suspension scaffold contains one or more platforms supported by ropes or
other non-rigid means from an overhead structure. The following are examples
of suspension scaffolds:
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•
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•
Single-point
Multi-point
Multi-level
Two-point Adjustable
Boatswain's chair
Catenary
Chimney hoist
Continuous run
Elevator false car
Go-devils
Interior hung
Mason's
Stone setter's
Suspension Requirements
When used properly, suspension scaffolds are safe to use at a job site. A
competent person/employer is required to:
Train employees to recognize the hazards associated with the different types
of scaffolds
Secure support devices by resting them on surfaces capable of supporting at
least four times the load imposed on them by the scaffold when operating at
the rated load of the hoist (or at least one-and-a-half times the load imposed
on them by the scaffold at the stall capacity of the hoist, whichever is greater)
Evaluate all direct connections prior to use to confirm that the supporting
surfaces are able to support the imposed load
Tie or otherwise secure scaffolds to prevent them from swaying
Protect employees from falling when they are working more than 10 feet
above a lower level by using guardrails, a personal fall arrest system, or both
Inspect ropes for defects prior to each work shift and after every occurrence
that could affect a rope's integrity
Use access, ladders, ramps, walkways, or similar surfaces when scaffold
platforms are more than 24 inches above or below a point of. When using
direct access, the surface must not be more than 24 inches above or 14 inches
horizontally from the surface
Require additional independent support lines (equal in number and strength to
the suspension lines and having automatic locking devices) when lanyards are
connected to horizontal lifelines or structural members on single-point or twopoint adjustable scaffolds
Ensure that no materials or devices can be used to increase the working height
on a suspension scaffold (This includes ladders, boxes, and barrels.)
Do not use emergency escape and rescue devices as working platforms unless
designed to function as suspension scaffolds and emergency systems
Suspension Components
Suspension scaffolds use several components to help make the system sturdy
and secure. Click each component to understand its use.
COUNTERWEIGHTS
Counterweights balance adjustable suspension in scaffolds. They must be
secured by mechanical means to the outrigger beams. The counterweight
must resist at least four times the tipping moment imposed by the scaffold
operating at either the rated load of the hoist, or one-and-a-half (minimum)
times the tipping moment imposed by the scaffold operating at the stall load
of the hoist, whichever is greater.
Within scaffolds, use only those items specifically designed as counterweights;
that is, solid materials that cannot be dislocated. The chart below list
examples of unacceptable counterweights.
Unacceptable Counterweights:
• Masonry units
• Rolls of roofing felt
• Sandbags
• Water buckets
OUTRIGGER BEAMS
Outrigger beams (thrustouts) are the structural members of a suspension or
outrigger scaffold that provide support. With regards to scaffolds:
Place outrigger beams perpendicular to their bearing support.
Secure tiebacks for outrigger beams to a structurally sound anchorage on the
building or structure. (Sound anchorages do not include standpipes, vents,
other piping systems, or electrical conduit.)
Install a single tieback perpendicular to the face of the building or structure.
Install two tiebacks at opposing angles when a perpendicular tieback cannot
be installed.
ROPES
The requirements for using suspension ropes include the following:
The suspension ropes must be long enough to allow the scaffold to be lowered
to the level below without the rope passing through the hoist, or the end of
the rope must be configured to prevent the end from passing through the
hoist.
OSHA prohibits the use of repaired wire.
Drum hoists must contain no fewer than four wraps of the rope at the lowest
point.
Suspension ropes supporting adjustable suspension scaffolds must be a
diameter large enough to provide sufficient surface area for the functioning of
brake and hoist mechanisms.
Suspension ropes also must be shielded from heat-producing processes.
Employers must replace wire rope when any of the following conditions exist:
• Kinks
• Six randomly broken wires in one rope lay or three broken wires in one
strand in one lay
• One-third of the original diameter of the outside wires is lost
• Heat damage
•
•
Evidence that the secondary brake has engaged the rope
Any other physical damage that impairs the function and strength of the
rope
POWER-OPERATED HOISTS
When using suspension scaffolds with power-operated hoists, workers are
required to observe the following rules:
Power-operated hoists used to raise or lower a suspended scaffold must be
tested and listed by a qualified testing laboratory.
The stall load is the load at which the prime mover (motor or engine) of a
power-operated hoist stalls or the power to the prime mover is automatically
disconnected. It must not exceed three times its rated load on any suspended
scaffold.
Gasoline power-operated hoists or equipment are not permitted, and drum
hoists must contain no fewer than four wraps of suspension rope at the lowest
point of scaffold travel.
Gears and brakes must be enclosed, and an automatic braking and locking
device, in addition to the operating brake, must engage when a hoist makes
an instantaneous change in momentum or an accelerated overspeed.
Suspension Welding
Welding can be done from suspended scaffolds when all of the following
requirements are met:
A grounding conductor is connected from the scaffold to the structure and is at
least the size of the welding lead.
The grounding conductor is not attached in series with the welding process or
the work piece.
An insulating material covers the suspension wire rope and extends at least
four feet above the hoist.
Insulated protective covers cover the hoist.
The tail line is guided, retained, or both so that it does not become grounded.
Each suspension rope is attached to an insulated thimble.
Each suspension rope and any other independent lines are insulated from
grounding.
Topic Summary
Please take a moment to review these key points about support and
suspension scaffolds before you continue with the next topic.
Support scaffolds are platforms that are supported by legs, outrigger beams,
brackets, poles, uprights, or some other type of rigid support to prevent
swaying and displacement.
Several of the key OSHA requirements are:
• Supported scaffolds with a height-to-base width ratio of more than 4:1
must be prevented from tipping by using restraint devices, such as
guying, tying, or bracing. In addition, a firm foundation is maintained by
placing scaffolds on base plates and mud sills.
• Employers are required to determine at each stage of erection and
dismantling if safe access and fall protection can be provided.
• Front-end loaders and similar pieces of equipment can be used to
support scaffold platforms only when the manufacturer designs the
equipment specifically for this purpose.
• Forklifts may be used only if the entire platform is attached to the forks
and the forklift does not move horizontally when workers are on the
platform.
Suspension scaffolds contain one or more platforms supported from an
overhead structure by ropes or other non-rigid means. Two specific safety
requirements are:
• Inspect ropes for defects prior to each work shift and after every
occurrence that could affect a rope's integrity.
• Use access ladders, ramps, walkways, or similar surfaces when scaffold
platforms are more than 24 inches above or below a point of access.
When using direct access, the surface must not be more than 24 inches
above or 14 inches horizontally from the surface.
Topic 3: Proper Use of Scaffolds
While you learned the general safety requirements for and types of scaffolds
here, this topic covers the proper use of scaffolds on construction sites to
ensure fall protection.
You will learn to:
• Identify safety requirements for fall protection systems -- especially the
use of guardrail systems
• Recognize safety procedures for erecting and dismantling scaffolds
• Determine the safety needs for personal fall arrest systems, falling
object protection, and inspections
• Specify safety measures presented by the weather, power lines, and
manufacturers, suppliers, and vendors
Fall Protection
OSHA has established that fall protection must be provided for employees any
time they are working on scaffolding 10 feet or more above a lower level.
A guardrail system is one of the most common forms of fall protection in the
construction industry. It is comprised mostly of toprails, midrails, and
toeboards, which are constructed from wood, pipe, structural steel, or wire
rope.
Guardrail systems must meet the following general criteria:
• The systems must be surfaced to protect employees from punctures or
lacerations and prevent clothing from being snagged
• Terminal posts should not overhang, creating a projection hazard
Toprails
As part of a guardrail system, there are several structural and material
specifications for secure toprails.
Structural
• 42 inches plus or minus 3 inches above a walking/working surface
• When employees are using stilts, the top edge height of the toprail must
increase an amount equal to the height of the stilts.
• Capable of withstanding a force of at least 200 pounds applied within
two inches in any downward or outward direction (When the test is
applied in a downward direction, the toprail must not deflect to a
distance less than 39 inches above the walking/working surface.)
Materials
• Flag at not more than six-foot intervals with high-visibility material
• At least 1/4 inch nominal diameter or thickness to prevent cuts and
lacerations
• Inspected as frequently as necessary to ensure strength and stability
(These may be a least desirable because they have to be inspected often
and may deteriorate rapidly.)
• Steel and plastic banding cannot be used as toprails
Hoisting
• When a guardrail system is used at a hoisting area, a chain, gate, or
removable guardrail section must be placed across the hoist access
opening when hoisting operations are not taking place.
Midrails
As part of a guardrail system, there are structural, material, and installation
stipulations for midrails.
Structural
• Midrails must be at least 1/4 inch nominal diameter or thickness to
prevent cuts and lacerations.
• Midrails, screens, mesh, intermediate vertical members, or equivalent
intermediate structural components must be capable of withstanding a
force of a least 150 pounds in any downward or outward direction at any
point along the midrail or other member.
Materials
• Inspect manila, plastic, or synthetic rope as frequently as necessary to
ensure strength and stability. (These may be a least desirable because
they have to be inspected often and may deteriorate rapidly.)
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•
•
Screens and mesh must extend from the toprail to the walking/working
surface and along the entire opening between the toprail vertical
supports.
Steel and plastic banding cannot be used as midrails.
Intermediate members such as balusters, when used between posts,
must not be more than 19 inches apart.
Installation
• Midrails, screens, mesh, intermediate vertical members, or equivalent
intermediate structural members must be installed between the toprail
and the walking/working surface when there are no walls or parapet
walls at least 21 inches high.
• Midrails must be installed midway between the toprail and the
walking/working surface.
Toeboards
As part of a guardrail system, the primary function of the toeboard is to
provide falling object protection.
Toeboards must be:
• Capable of withstanding a force of a least 50 pounds in any downward or
outward direction at any point along the toeboard.
• At least 3 1/2 inches in height from their top edge to the
walking/working surface.
Toeboards cannot:
• Be more than 1/4 inch above the walking/working surface.
• Have openings that are greater than 1 inch.
Where tools, equipment, or materials are piled higher than the top edge of the
toeboard, paneling or screening must be erected from the walking/working
surface to the toprail or midrail, whichever is sufficient to protect workers
below.
Holes
Here are safety measures for using guardrail holes to pass material and to
access points.
To pass material
• When holes are used to pass material, the hole cannot have more than
two sides that are removable. It must be covered or provided with
guardrails on all sides when it is not in use.
To access
• When holes are used for access points for ladders or stairways, gates
must be used, or the point of access must be offset to prevent
employees from walking into the hole.
• If guardrails are used on unprotected sides or edges of ramps, runways
or other walkways, holes must be erected on each side or edge.
Other Considerations
You now understand how to use guardrails responsibly. Others were not so
fortunate.
OSHA Case
The following case reports are of falls investigated by OSHA:
• A contract employee was taking measurements from an unguarded
scaffold inside a reactor vessel when he either lost his balance or
stepped backwards, fell 14 1/2 feet, and died.
• An employee was installing overhead boards from a scaffold platform
consisting of two 2" x 10" boards with no guardrails. He lost his balance,
fell 7 1/2 feet to the floor, and died.
Supporting Scaffolds
The prior OSHA standard did not require that employers provide safe access
and fall protection during erection or dismantling operations. Here is a list of
current standards:
• OSHA recognizes that compliance may not be feasible during certain
scaffold erection and dismantling operations. However, employers will be
required to determine at each stage of erection and dismantling if safe
access and fall protection can be provided and, if so, to comply with the
pertinent requirements.
• The employer is responsible for evaluating whether providing access and
fall protection for employees is feasible and safer (i.e., does not create a
greater hazard.)
• A competent person who has the knowledge and experience necessary
must make the appropriate determination.
•
This evaluation shall include a determination whether, alternatively,
partial compliance may be feasible and safer under the circumstances.
Personal Fall Arrest Systems
Personal fall arrest systems can be used on scaffolding when there are no
guardrail systems in place. A personal fall arrest system consists of a body
harness, components of the harness such as Dee-rings and snaphooks,
lanyards, lifelines, and anchorage points.
Personal fall arrest systems should be used on the following types of scaffolds:
• Boatswain's Chair
• Catenary
• Float
• Needle Beam
• Ladder
• Pump Jack
Either vertical or horizontal lifelines can be used. Lifelines must be
independent of support lines and suspension ropes, and they cannot be
attached to the same anchorage point.
When using a personal fall arrest system on an aerial lift, attach the system to
the boom or basket.
Personal fall arrest systems must be used in conjunction with guardrails when
employees are working on single-point and two-point adjustable suspension
scaffolds and self-contained adjustable scaffolds that are supported by ropes.
Falling Object Protection
Employers must protect employees from falling hand tools, debris, and other
small objects. Here is a list of special precautions:
• A hard hat must be worn.
• A guardrail system including a toeboard can be used as falling object
protection.
• No material or equipment excluding mortar and masonry can be stored
within four feet of working edges.
• Excess mortar, broken or scattered masonry units, and all other
materials and debris must be removed from the working area at regular
intervals.
• You can also use canopies strong enough to prevent collapse or
penetration by any object that may fall onto them.
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Barricade the area on which objects could fall and prohibit employees
from entering the barricaded area.
When objects are too large, heavy, or massive to be contained or
deflected by any of the above-listed measures, the employer must place
such potential falling objects away from the edge of the surface from
which they could fall and secure the materials to prevent their falling.
Topic 4: Proper Use Of Scaffolds
In addition to fall protection, other important safety challenges and issues
affect employees working with scaffolds. Click each issue for a briefing on its
safety measures.
The following is a list of basic requirements for the use of scaffolds on
construction sites.
Dos
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Have a competent person inspect for visible defects before each work
shift and after any occurrence that could affect a scaffold's structural
integrity.
Repair, replace, brace, or remove from service immediately any part of a
scaffold that has been damaged or unacceptably weakened.
Implement a job site housekeeping program to avoid tripping hazards.
Don'ts
• Don't load scaffolds in excess of their maximum intended loads or rated
capacities, whichever is less.
• Don't use shore or lean-to scaffolds.
• Don't move scaffolds horizontally while employees are working on them.
• Don't allow debris to accumulate.
WEATHER
The following is a list of several weather requirements when using scaffolds:
• Working on scaffolds is prohibited during lightning storms, high winds, or
inclement weather unless (1) a competent person has determined that it
is safe for employees to be on the scaffold and (2) the employees are
protected by a personal fall arrest system or wind screens.
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Windscreens cannot be used unless the scaffold is secured against the
anticipated wind forces that are to be imposed on the scaffold system.
Employees are not allowed to work on scaffolds covered with snow, ice,
or other slippery material except to remove such materials.
ENERGIZED POWER LINES
Scaffolds near energized power lines cannot be erected, used, dismantled,
altered, or moved closer than the distances stated below.
However, scaffolds can be moved closer if it is necessary for the performance
of work, providing the power lines are either de-energized or protective
coverings are installed to prevent contact.
MANUFACTURERS, SUPPLIERS, AND VENDORS
Before purchasing or putting into use a scaffold system, an employer should
obtain information about the system from the supplier.
Not all systems may need to be individually tested. The performance of some
systems may be based on data and calculations derived from testing of similar
systems, provided that enough information is available to demonstrate
similarity of function and design.
Employers should obtain comprehensive instructions from the supplier on the
proper use of the scaffold system, including:
• The force measured during the sample force test
• Caution statements on critical-use limitations
• Application limits
• Methods of inspection, use, cleaning, and storage
LADDERS
Ladders are not to be used on scaffolds to increase the working height of
employees except on large area scaffolds where employers have satisfied the
following criteria:
• The ladder is placed against a structure (not part of the scaffold) and the
scaffold is secured against the sideways thrust exerted by the ladder.
•
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The platform units are secured to the scaffold to prevent their
movement.
The ladder legs are on the same platform and are secured to prevent
them from slipping or being pushed off the platform.
Topic Summary
Please take a moment to review these major points before you continue to the
next topic.
• Guardrail systems must follow OSHA's criteria for use of toprails,
midrails, toeboards, hoisting, and holes.
• At each stage of erecting and dismantling a scaffold, OHSA requires safe
access and fall protection.
• Consider all OHSA regulations for personal fall arrest systems before
using the fall protections devices on a job site.
• The OSHA standards cover special precautions for protecting workers
from falling objects.
• A competent person must consider safety measures for unsafe
conditions caused by bad weather, energized power lines, and the
manufacturer's safeguard recommendations.
Topic 5: Specific Types of Scaffolds
There are many types of scaffolds that can be grouped into three major
categories. Click each category to see a short description.
* Supported scaffolds: A supported scaffold is a platform that is supported by
legs, outrigger beams, brackets, poles, uprights, posts, frames, or some type
of similar rigid support.
* Suspended scaffolds: A suspension scaffold contains one or more platforms
supported by ropes or other non-rigid means from an overhead structure.
* Special use scaffolds: A special use scaffold is an assembly designed for a
specific purpose where other scaffold systems might be more difficult to use.
Types of Lifts
There are two types of lifts: aerial lifts and scissor lifts, both called aerial work
platforms. These aerial work platforms, if used correctly, provide quick and
safe access to work areas that at one time could be reached only from
scaffolding or a crane's manbasket. As with any tool, however, there are right
and wrong ways to use them.
Aerial lifts: Aerial lifts can move in more than a single direction, increasing the
risk of mishaps.
Scissor lifts: Scissor lifts are efficient one-direction lifts. They provide a solid
surface from which to work.
Topic Summary
Please take a moment to review these points before you continue with the
next topic.
• The three major categories of scaffolds are supported scaffolds,
suspension scaffolds, and special use scaffolds.
• The two types of lifts that provide quick and safe access to work areas
are aerial lifts and scissor lifts.
• The largest number of violation issued by OSHA occurred in scaffolds
more than 10 feet above the ground.
Topic 6: Supported Scaffolds
Here you will learn about the specific safety requirements for various types of
supported scaffolds. Upon completing this topic, you will be able to:
• Describe safety requirements of fabricated frame scaffolds
• Describe safety requirements of tube and coupler scaffolds
• Describe safety requirements of mobile scaffolds
• Describe safety requirements of pole scaffolds
Fabricated Frame Scaffolds
Take a moment to look at the following specific requirements that you need to
be cautious about when working with fabricated frame scaffolds.
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•
In order to prevent creating unnecessary fall hazards when moving
platforms to the next level on fabricated frame scaffolds, the existing
platform must be left in place until the new end frames have been set in
place and braced.
All frames and panels have to be braced by cross, horizontal, or diagonal
braces, or a combination of these that secures the vertical members
together laterally. The cross braces must be long enough to
automatically square and align the vertical members so that the erected
scaffold is always plumb, level, and square. All of the bracing
connections must be secured.
Key Point: A registered professional engineer must design scaffolds that
are higher than 125 feet above their base plates. These scaffolds must
be constructed and loaded in accordance with such design.
What are the other safety requirements for fabricated frame scaffolds?
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Frames and panels are to be joined together vertically by using coupling
or stacking pins. In addition, at any time where uplift can occur that
would displace the scaffold's end frames or panels, they must be locked
together.
Brackets that are used to support cantilevered loads on supported
scaffolds must meet the following requirements:
They must be placed so that the side brackets are parallel to the frames
and the end brackets are at a 90-degree angle to the frame
They cannot be bent or twisted from their normal positions
They can be used only to support workers, unless a qualified engineer
has designed the scaffold for other loads and built it to withstand the
tipping forces caused by those other loads being placed on the bracketsupported section of the scaffold.
Tube and Coupler Scaffolds
Do you know about the specific safety requirements for working with tube and
coupler scaffolds?
• Whenever scaffold platforms are being moved to the next level, the
existing platform has to be left in place until the new bearers have been
set and braced.
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You must install transverse bracing (forming an "X" across the width of
the scaffold) at the scaffold ends, at least at every third set of posts
horizontally (measured from only one end), and every fourth runner
vertically. This bracing must extend diagonally from the inner or outer
posts or runners upward to the next outer or inner posts or runners, and
ties need to be installed at the bearer levels between the bracing.
On straight-run scaffolds, longitudinal bracing across the inner and outer
rows of posts has to be installed diagonally in both directions. It must
extend from the base of the end posts upward to the top of the scaffold
at approximately a 45-degree angle. Bracing must be installed as close
as possible to the intersection of the bearer and post or runner and post.
On scaffolds whose length is greater than their height, the bracing needs
to be repeated beginning at least at every fifth post.
On scaffolds whose length is less than their height, this bracing must be
installed from the base of the end posts upward to the opposite end
posts, and then in alternating directions until reaching the top of the
scaffold.
What are the other safety requirements when working with tube and coupler
scaffolds?
• Where conditions do not allow the bracing to be attached to the posts, it
should be attached to the runners as close to the post as possible.
• Bearers are to be installed transversely between posts and, when
coupled to the posts, must have the inboard coupler bear directly on the
runner coupler. When the bearers are coupled to the runners, the
couplers must be as close to the posts as possible.
• Bearers must extend beyond the posts and runners and provide full
contact with the coupler.
• Runners have to be installed along the length of the scaffold, located on
both the inside and outside posts at level heights. (When tube and
coupler guardrails and midrails are used on outside posts, they may be
used in lieu of outside runners.)
• Runners have to be interlocked on straight runs to form continuous
lengths and be coupled to each post. The bottom runners and bearers
should be located as close to the base as possible.
• Couplers must be made of structural metal, such as dropforged steel,
malleable iron, or structural-grade aluminum. The use of gray cast iron
is prohibited.
•
Tube and coupler scaffolds over 125 feet high must be designed by a
registered professional engineer and be constructed and loaded in
accordance with such design.
Mobile Scaffolds
You can ride on a mobile scaffold only when all of the following conditions
exist.
1. The surface on which the mobile scaffold is being moved is within three
degrees of level and free of pits, holes, and obstructions
2. The height-to-base width ratio of the scaffold during movement is twoto-one or less
3. Outrigger frames, when used, are installed on both sides of the scaffold
4. When power systems are used, the propelling force is applied directly to
the wheels and does not produce a speed in excess of one foot per
second
5. No employee is on any part of the mobile scaffold that extends outward
beyond the wheels, casters, or other supports
Key Point: Scaffold casters and wheels must be locked to prevent
movement of the scaffold while the scaffold is used in a stationary manner.
This can be accomplished with positive wheel and/or wheel and swivel
locks.
What other safety requirements do you need to know when working with
mobile scaffolds?
• Mobile scaffolds must be braced by cross, horizontal, or diagonal braces,
or any combination of these, in order to prevent racking or collapse of
the scaffold. In addition, the bracing will secure vertical members
together laterally so that they are automatically squared and aligned.
• Manual force used to move the mobile scaffold must be applied as close
to the base as practicable, but not more than five feet above the
supporting surface.
• Power systems used to propel mobile scaffolds have to be designed for
such use. Forklifts, trucks, similar motor vehicles or add-on motors are
not to be used to propel scaffolds unless the mobile scaffold is designed
for such systems.
• Mobile scaffolds must be stabilized to prevent tipping during movement.
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Platforms must not extend outward beyond the base supports of the
scaffold unless outrigger frames or equivalent devices are used to
ensure stability.
Where leveling of the scaffold is necessary, screw jacks should be used.
Caster stems and wheel stems must be secured in scaffold legs or
adjustment screws.
Before a scaffold is moved, each employee on the scaffold must be made
aware of the move.
Pole Scaffolds
The fourth type of supported scaffold is a pole scaffold. Read the following
requirements you must consider when working with pole scaffolds.
• Whenever scaffold platforms are being moved to the next level, the
existing platform has to be left in place until the new bearers have been
set and braced.
• Crossbracing must be installed between the inner and outer sets of poles
on double-pole scaffolds.
• Diagonal bracing in both directions has to be installed across the entire
inside face of double-pole scaffolds.
• Diagonal bracing in both directions must be installed across the entire
outside face of all double- and single-pole scaffolds.
• Runners and bearers must be installed on edge and bearers will extend a
minimum of three inches over the outside edges of runners.
• Runners must extend over a minimum of two poles and be supported by
bearing blocks securely attached to the poles.
• Braces, bearers, and runners are not to be spliced between poles.
• When wooden poles are spliced, the ends have to be squared and the
upper section must rest squarely on the lower section. Wood splice
plates must be provided on at least two adjacent sides and extend at
least two feet on either side of the splice, overlap the abutted ends
equally, and have at least the same cross-sectional areas as the pole.
• Pole scaffolds over 60 feet high must be designed by a registered
professional engineer and be constructed and loaded in accordance with
that design.
Topic Summary
Please take a moment to review these points before you continue with the
next topic.
• The types of supported scaffolds include:
o Fabricated frame scaffolds
o Tube and coupler scaffolds
o Mobile scaffolds
o Pole scaffolds
• In order to prevent fall hazards when moving platforms to the next level
on fabricated frame scaffolds, the existing platform must be left in place
until the new end frames have been set in place and braced.
• All frames and panels on fabricated frame scaffolds have to be braced by
cross, horizontal, or diagonal braces, or a combination of these that
secures the vertical members together laterally.
• A registered professional engineer must design fabricated frame
scaffolds that are higher than 125 feet above their base plates. These
scaffolds must be constructed and loaded in accordance with such
design.
• Scaffold casters and wheels must be locked to prevent movement of the
mobile scaffold while the scaffold is used in a stationary manner. This
can be accomplished with positive wheel and/or wheel and swivel locks.
Topic 7: Suspended Scaffolds
Here you will learn about the specific safety requirements for various types of
suspended scaffolds. Upon completing this topic, you will be able to:
• Describe safety requirements of single-point adjustable suspension
scaffolds (boatswain's chair)
• Describe safety requirements of two-point adjustable suspension
scaffolds (swing stages)
• Describe safety requirements of multi-point adjustable suspension
scaffolds
• Describe safety requirements of multi-level suspended scaffolds
• Describe safety requirements of catenary scaffolds
• Describe safety requirements of float (ship) scaffolds
• Describe safety requirements of interior hung scaffolds
• Describe safety requirements of needle beam scaffolds
Single-Point Adjustable Suspension Scaffolds
Take a moment to look at the following specific requirements for working with
single-point adjustable suspension scaffolds.
• The supporting rope between the scaffold and the suspension device
must be kept vertical unless all of the following conditions are met:
o A qualified person has designed the rigging.
o The scaffold is accessible to rescuers.
o The supporting rope is protected to ensure that it will not chafe at
any point where a change in direction occurs.
o The scaffold is positioned so that swinging cannot bring the
scaffold into contact with another surface.
• Boatswain's chair tackle must consist of the correct size ball bearings or
bushed blocks containing safety hooks and properly "eye-spliced"
minimum 5/8-inch diameter first-grade manila rope, or other rope that
will satisfy the criteria (e.g., strength and durability) of manila rope.
• Boatswain's chair seat slings must be reeved through four corner holes
in the seat. They must cross each other on the underside of the seat and
be rigged to prevent slippage that could cause an out-of-level condition.
• Boatswain's chair seat slings must be made from a minimum of 5/8-inch
diameter fiber, synthetic, or other rope that will satisfy the criteria (e.g.,
strength, slip resistance, durability, etc.) of first-grade manila rope.
• When a heat-producing process such as gas or arc welding is being
conducted, boatswain's chair seat slings must use a minimum of 3/8inch wire rope.
• Non-cross-laminated wood boatswain's chairs must be reinforced on
their undersides by cleats securely fastened to prevent the boards from
splitting.
Two-Point Adjustable Suspension Scaffolds
When working with two-point adjustable suspension scaffolds, the following
additional requirements must apply.
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Platforms must be 20-36 inches wide unless designed by a qualified
person to prevent unstable conditions. Platforms must be the laddertype, plank-type, beam-type, or light-metal type.
The platform must be securely fastened to hangers (stirrups), most
commonly by U-bolts.
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The blocks for fiber or synthetic ropes must consist of at least one
double and one single block, and the sheaves of all blocks must fit the
size of the rope used.
Two-point scaffolds cannot be bridged or otherwise connected to one
another during raising and lowering operations unless the bridge
connections are articulated (attached), and the hoists are the proper
capacity.
Passage can be made from one platform to another only when the
platforms are at the same height, are abutting, and walk-through
stirrups specifically designed for this purpose are used.
Multi-Point Adjustable Suspension Scaffolds
What criteria must be met when working with multi-point adjustable
suspension scaffolds?
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When two or more scaffolds are used, they must be bridged to one
another if they are designed to be bridged. The bridge connections must
be articulated and the hoists properly sized.
If bridges are not used then passage may be made from one platform to
another only when the platforms are at the same height and abutting.
Scaffolds must be suspended from metal outriggers, brackets, wire rope
slings, hooks, or means that are equivalent in strength and durability.
Multi-Level Suspended Scaffolds
When working with multi-level adjustable suspension scaffolds, the following
requirements apply:
• Scaffolds must be equipped with additional independent support lines,
equal in number to the number of points supported, of equivalent
strength to the suspension ropes, and rigged to support the scaffold in
the event the suspension rope(s) fail.
• Independent support lines and suspension ropes must not be attached to
the same points of anchorage.
• Supports for platforms must be attached directly to the support stirrup
and not to any other platform.
Catenary Scaffolds
Take a moment to look at the following requirements for working with
catenary scaffolds:
• No more than one platform can be placed between consecutive vertical
pickups, and no more than two platforms can be used on a catenary
scaffold.
• Platforms supported by wire ropes must have hook-shaped stops on
each end of the platforms to prevent them from slipping off the wire
ropes. These hooks have to be placed so that they will prevent the
platform from falling if one of the horizontal wire ropes breaks.
• Wire ropes must not be tightened to the extent that the application of a
scaffold load will overstress them.
• Wire ropes must be continuous and without any splices between the
anchors.
Float (Ship) Scaffolds
When working with float (ship) scaffolds, the following additional requirements
apply:
• The platform must be supported by a minimum of two bearers, each of
which must project a minimum of six inches beyond the platform on
both sides. Each bearer must be securely fastened to the platform.
• Rope connections must be made so that the platform cannot shift or slip.
• When only two ropes are used with each float:
• They must be arranged to provide four ends that are securely fastened
to overhead supports.
• Each supporting rope must be hitched around one end of the bearer and
pass under the platform to the other end of the bearer where it is
hitched again, leaving sufficient rope at each end for the supporting ties.
Interior Hung Scaffolds
What about interior hung scaffolds? What would be the proper place(s) to
suspend the interior hung scaffolds?
• Scaffolds must be suspended only from the roof structure or other
structural member such as ceiling beams.
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Overhead supporting members (roof structure, ceiling beams, or other
structural members) must be inspected and checked for strength before
the scaffold is erected.
Suspension ropes and cables must be connected to the overhead
supporting members by shackles, clips, thimbles, or other means with
the appropriate strength and durability.
Needle Beam Scaffolds
Take a look at other requirements for working with needle beam scaffolds.
• Scaffold support beams must be installed on edge.
• Ropes or hangers must be used for supports, except that one end of a
needle beam scaffold may be supported by a permanent structural
member.
• The ropes must be securely attached to the needle beams.
• The support connection must be arranged to prevent the needle beam
from rolling or becoming displaced.
• Platform units must be securely attached to the needle beams by bolts
or equivalent means. Cleats and overhang are not adequate means of
attachment.
Topic Summary
Please take a moment to review these points before you continue with the
next topic.
• A suspension scaffold contains one or more platforms supported by
ropes or other non-rigid means from an overhead structure. Following
are different types of suspended scaffolds:
o Single-point adjustable suspension scaffolds (boatswain's chair)
o Two-point adjustable suspension scaffolds (swing stages)
o Multi-point adjustable suspension scaffolds
o Multi-level suspended scaffolds
o Catenary scaffolds
o Float (ship) scaffolds
o Interior hung scaffolds
o Needle beam scaffolds
Topic 8: Special Use Scaffolds
In this topic, you will learn about various types of special use scaffolds. A
special use scaffold is an assembly designed for a specific purpose where other
scaffold systems might be more difficult to use. Upon completing this topic,
you will be able to:
• Describe specific safety requirements of Form scaffolds and carpenter's
bracket scaffolds
• Describe specific safety requirements of roof bracket scaffolds
• Describe specific safety requirements of outrigger scaffolds
• Describe specific safety requirements of pump jack scaffolds
• Describe specific safety requirements of ladder jack scaffolds
• Describe specific safety requirements of window jack scaffolds
• Describe specific safety requirements of horse scaffolds
• Describe specific safety requirements of crawling boards (chicken
ladders)
• Describe specific safety requirements of step, platform, and trestle
ladder scaffolds
Form Scaffolds and Carpenter's Bracket Scaffolds
When working with form scaffolds and carpenter's bracket scaffolds, this
requirement applies.
• Each bracket, except those for wooden bracket-form scaffolds, must be
attached to the supporting formwork or structure by means of one or
more of the following:
o Nails
o A metal stud attachment device
o Welding
o Hooking over a secured structural supporting member, with the
form wales either bolted to the form or secured by snap ties or tie
bolts extending through the form and securely anchored
o For carpenter's bracket scaffolds only, by a bolt extending through
to the opposite side of the structure's wall
• Wooden bracket-form scaffolds must be an integral part of the form
panel.
• Folding type metal brackets, when extended for use, must be either
bolted or secured with a locking-type pin.
Roof Bracket Scaffolds
What do you need to be cautious about when you are working with roof
bracket scaffolds?
• First, scaffold brackets must be constructed to fit the pitch of the roof
and must provide a level support for the platform.
• Second, brackets (including those provided with pointed metal
projections) must be anchored in place by nails unless it is impractical to
use nails. When nails are not used, brackets must be secured in place
with first-grade manila rope of at least 3/4-inch diameter or the
equivalent.
Outrigger Scaffolds
The inboard end of outrigger beams, measured from the fulcrum point to the
extreme point of anchorage, must be not less than one and one-half times the
outboard end in length.
The following requirements should also be met when working with outrigger
scaffolds:
• Outrigger beams fabricated in the shape of an I-beam or channel must
be placed so that the web section is vertical.
• The fulcrum point of outrigger beams must rest on secure bearings at
least six inches in each horizontal dimension.
• Outrigger beams must be secured in place against movement and
securely braced at the fulcrum point against tipping.
• The inboard ends of outrigger beams must be securely anchored either
by means of braced struts bearing against sills in contact with the
overhead beams or ceiling, or by means of tension members secured to
the floor joists underfoot, or by both.
• The entire supporting structure must be securely braced to prevent any
horizontal movement.
• To prevent displacement, platform units must be secured to outriggers.
• Scaffolds and scaffold components must be designed by a registered
professional engineer and constructed and loaded in accordance with
such design.
Pump Jack Scaffolds
Take a look at the following requirements for pump jack scaffolds.
• Each pump jack bracket must have two positive gripping mechanisms to
prevent any failure or slippage.
• Pump jack brackets, braces, and accessories must be fabricated from
metal plates and angles.
• Poles must be secured to the structure by rigid triangular bracing or
equivalent at the bottom, top, and other points as necessary. When the
pump jack has to pass bracing already installed, an additional brace
must be installed approximately four feet above the brace to be passed
and left in place until the pump jack has been moved and the original
brace reinstalled. Click here to see what this means.
• When guardrails are used for fall protection, a workbench may be used
as the top rail only if it meets all the requirements of a guardrail. Click
here to see what this means.
• Workbenches must not be used as scaffold platforms.
• When poles are made of wood, the pole lumber must be straight-grained
and free of shakes, large loose or dead knots, and other defects that
might impair strength.
• When wood poles are constructed of two continuous lengths, they must
be joined together with the seam parallel to the bracket. Click here to
see what this means.
• When two-by-fours are spliced to make a pole, mending plates must be
installed at all splices to develop the full strength of the member. Click
here to see a violation to this requirement.
Key Point: Each pump jack bracket must have two positive gripping
mechanisms to prevent any failure or slippage.
Ladder Jack Scaffolds
When working with ladder jack scaffolds, the following requirements apply:
• Platforms must not exceed a height of 20 feet.
• All ladders used to support ladder jack scaffolds must meet the
requirements of OSHA standards for ladders.
• Job-made ladders must not be used to support ladder jack scaffolds.
Click here to see an example.
• The ladder jack must be designed and constructed so that it will bear on
the side rails and ladder rungs or on the ladder rungs alone. If bearing
on rungs only, the bearing area must include a length of at least 10
inches on each rung.
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Ladders used to support ladder jacks must be placed, fastened, or
equipped with devices to prevent slipping. Click here to see an example.
Scaffold platforms must not be bridged one to another. Click here to see
an example.
Window Jack Scaffolds
Window jack scaffolds must be used only for the purpose of working at the
window opening through which the jack is placed. Other requirements are:
• Scaffolds must be securely attached to the window opening.
• Window jacks must not be used to support planks placed between one
window jack and another, or for other elements of scaffolding.
Horse Scaffolds
When working with horse scaffolds, the following requirements must be met:
• Scaffolds must not be constructed or arranged more than two tiers or,
10 feet high, whichever is less.
• When horses are arranged in tiers:
• Each horse must be placed directly over the horse in the tier below.
• The legs of each horse must be nailed down or otherwise secured to
prevent displacement.
• Each tier must be cross-braced.
Crawling Boards (Chicken Ladders)
There are two requirements you should remember when working with crawling
boards:
• Crawling boards must extend from the roof peak to the eaves when used
in connection with roof construction, repair, or maintenance.
• Crawling boards must be secured to the roof by ridge hooks or by means
that meet equivalent criteria (e.g., strength and durability).
Step, Platform, and Trestle Ladder Scaffolds
Here are the safety requirements:
• Scaffold platforms must not be placed any higher than the second
highest rung or step of the ladder supporting the platform.
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Job-made ladders must not be used to support such scaffolds.
Ladders used to support step, platform, and trestle ladder scaffolds must
be placed, fastened, or equipped with devices to prevent slipping.
Scaffolds must not be bridged one to another.
Topic Summary
Please take a moment to review these points before you continue with the
next topic.
• Various types of special use scaffolds discussed in this topic were:
o Form scaffolds and carpenter's bracket scaffolds
o Roof bracket scaffolds
o Outrigger scaffolds
o Pump jack scaffolds
o Ladder jack scaffolds
o Window jack scaffolds
o Horse scaffolds
o Crawling boards (chicken ladders)
o Step, platform, and trestle ladder scaffolds
• When you use roof bracket scaffolds, scaffold brackets must be
constructed to fit the pitch of the roof and must provide a level support
for the platform.
• When you use pump jack scaffolds, each pump jack bracket must have
two positive gripping mechanisms to prevent any failure or slippage.
Topic 9: Aerial Work Platforms
Lifts, collectively called aerial work platforms, provide quick and safe access to
work areas that could only be reached from scaffolding or a crane's man
basket. In this topic you will learn about two types of lifts: aerial lifts and
scissor lifts.
Upon
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completing this topic, you will be able to:
Identify different types of aerial lifts
List unique hazards for aerial lifts
Describe safety requirements for scissor lifts
State safe operating procedures for aerial and scissor lifts
Aerial Lifts
Aerial lifts can move in more than a single direction. Different types of aerial
lifts used to elevate personnel to job sites above ground. They are:
• Extensible boom platforms
• Aerial ladders
• Articulating boom platforms
• Vertical towers
Key Point: Remember before operating any aerial work platform to always
read and follow the manufacturer's safety and operation manual! This
information must be kept on the rig and can usually be found in a container
tied to the machine's frame or rails.
Aerial lifts can move in more than a single direction, increasing the risk of
mishaps, so it's important to remember the following:
• Whenever working out of an aerial lift, a full-body harness must be worn
and properly attached to the basket. A sudden jolt has thrown people
from aerial lifts before they could react.
• Never drive the aerial lift when it is elevated above the limit the
manufacturer considers safe. Each piece of equipment will state what
the maximum extension can be while being driven.
• Always maintain a safe distance from debris piles, drop-offs, floor
openings, etc.
Scissor Lifts
Scissor lifts are efficient one-direction lifts. They provide a solid surface to
work from, but always remember:
Key Point: A worker in a scissor lift need be protected from falling by a
properly designed and maintained guardrail system. However, if the
guardrail system is less than adequate, or the worker leaves the safety
of the work platform, an additional fall protection device would be
required, such as a body harness and lanyard.
Other requirements for scissor lifts include the following:
• Guardrail, midrails, and toe boards must be in place. The toe board can
be omitted at the door.
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The platform must be equipped with a mechanical parking brake that will
hold the unit securely on any slope it is capable of climbing. The brake
should be tested periodically.
Never use the lift's rails, planks across the rails, or a ladder, to gain
additional height.
Safe Operating Procedures
Take a moment to see the safe operating procedures required for aerial and
scissor lifts.
Key Point: Only trained and authorized people should operate the lift. A
qualified instructor must make sure that every operator reads and\or
understands the equipment's safety and operating instructions. This
includes all of the warning decals and labels mounted on the machine.
Other requirements for scissor lifts include the following:
• Always check for overhead obstructions before driving or elevating the
platform.
• Refuel tanks only when the unit is turned off. If battery powered, the
batteries should be charged only in a well-ventilated area, away from
any open flame.
• Prior to each shift the operator should perform a safety inspection; this
includes both a visual inspection and a function test. If a problem is
found, get the lift repaired.
• Elevate the platform only when it is on a firm, level surface. Although
many lifts look like rough terrain pieces of equipment, they are not.
Their large tires do allow the equipment to access somewhat difficult
areas, but once in position they are designed to be out of level only five
degrees while in operation. This amounts to 10 inches in a 10-foot wheel
span. In addition, the lift must have a tilt alarm that activates when the
machine is more than five degrees out of level.
Topic Summary
Please take a moment to review these points before you continue with the
next topic.
• Whenever working out of an aerial lift, a full-body harness must be worn
and be properly attached to the basket.
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Never drive the aerial lift when it is elevated above the limit the
manufacturer considers safe.
A worker in a scissor lift need be protected from falling only by a
properly designed and maintained guardrail system. However, if the
guardrail system is less than adequate, or the worker leaves the safety
of the work platform, an additional fall protection device would be
required.
Only trained and authorized people should operate the lift. A qualified
instructor must make sure that every operator reads and\or understands
the equipment's safety and operating instructions. This includes all of
the warning decals and labels mounted on the machine.
Lesson Summary
This lesson contained information and instruction about using scaffolds. By
completing this lesson, you should have the knowledge to discuss the following
topics. Take a moment to see if you can do the following:
• Determine the general safety requirements for scaffolds
• Identify the different types and components of scaffolds
• Recognize the proper safety precautions and use of scaffolds
• Define supported, suspended, and special use scaffolds and define aerial
and scissor lifts
• State specific safety requirements of various types of supported
scaffolds
• Describe specific safety requirements of various types of suspended
scaffolds
• Apply specific safety requirements for various types of special use
scaffolds in your work
• State specific safety requirements of aerial and scissor lifts
Fall Protection
Introduction
The importance of fall protection can be summed up in one word: gravity. It is
a scientific fact that if you fall from an elevation you will continue to fall until
something breaks your fall, often with catastrophic results. Yet on the
construction site when fall protection is mentioned, you often hear that "It
can't be done!" However, everyone knows that "It should be done." The
questions that should be asked are "How can we provide fall protection?" and
"When are we supposed to provide it?" The current loss data associated with
falls is staggering, as hundreds die every year and hundreds of thousands are
injured.
An OSHA study involving 99 fall-related fatalities suggests that virtually all of
those deaths could have been prevented by the use of guardrails, body belts,
body harnesses, safety nets, covers, or other means, which would have
reduced employee exposure to the fall hazard.
Many employees believe that there will be time to regain their balance before
they fall; this is not always true.
Lesson Overview
This lesson provides you with an overview of the elements of a fall protection
program. The lesson introduces OSHA's compliance regulations for employer
requirements, coverage, and training. This lesson also covers the different
types of fall protection systems available and how and when to use them
properly. You also will learn about fall protection planning and training
requirements.
Upon completing this lesson, you will be able to:
• Define OSHA's fall protection rule and explain the employer's
responsibility to provide fall protection
• Outline OSHA's fall protection training program requirements
• Identify the potential risks and activities where fall protection is needed
• Select applicable prevention method for specific fall hazards
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Explain hierarchy of control and identify fall protection system options
Describe components of personal fall arrest systems and how to inspect,
wear, and care for the systems
Describe components of a guardrail system and the types of guardrails
Distinguish when and how to use positioning device systems, warning
lines systems, and covers
Determine when and how to use safety monitoring systems, controlled
access zone, and safety nets
State the fall protection plan requirements, including falling object
protection plans
State fall protection training requirements, topics, and requirements for
a certification. Identify situations where you need to provide fall
protection training.
Why Learn This Lesson?
OSHA recognizes that incidents are, generally, complex events involving a
combination of factors. Accordingly, the agency notes that a number of human
and equipment-related issues must be addressed to protect employees from
fall hazards.
Among those issues are the following:
• The need to know where protection is required
• The selection of fall protection systems appropriate for given situations
• The proper construction and installation of safety systems
• The proper supervision of employees
• The implementation of safe work procedures
• The proper training in the selection, use, and maintenance of fall
protection systems
Falls continue to be the leading killer of construction workers. This lesson will
help you understand how to prevent falls in daily construction operations.
Topic 1: OSHA's Fall Protection Standards
The Rule
OSHA's fall protection standards are covered by a rule. The rule requires that
whenever construction workers are exposed to a fall hazard of six feet or
more, employers must take action to protect their workers from falling. This
rule applies to all construction activities unless another construction standard
specifically addresses fall protection, such as steel erection of buildings,
scaffolding, and stairways/ladders.
OSHA recognizes that accidents involving falls generally are complex events
often involving a variety of factors. Consequently, the standard for fall
protection deals with both the human and equipment-related issues in
protecting workers from fall hazards.
Among those issues are the following:
• The need to know situations in which protection is required
• Selection of fall protection systems appropriate for given situations
• Construction and installation of safety systems
• Supervision of employees
• Implementation of safe work procedures
• Training in the selection, use, and maintenance of fall protection
systems
Employers' Requirements
The OSHA rule clarifies what an employer must do to provide fall protection for
employees, such as identifying and evaluating fall hazards and providing
specific training.
Requirements to provide fall protection for workers on scaffolds and ladders
and for workers engaged in steel erection of buildings are covered in other
OSHA regulations.
Employers are given many options on protecting employees from fall hazards,
including:
• Safety monitoring systems
• Controlled access zones
• Safety nets
• Guardrails
• Personal fall arrest systems
• Warning lines
• Positioning device systems
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Fall protection plans
Employers' Steps
OSHA outlines three basic steps for employers to effectively assess their fall
protection plan.
1. The first thing an employer must do when addressing fall protection is to
assess the workplace and determine if the walking or working surfaces
on which employees are to work have the strength and structural
integrity to safely support them.
2. The employer needs to select a specific fall protection method.
Employees are not permitted to work there until it is determined that the
work surface will support the workers. Once employers have determined
that the surface is safe for employees to work on, the employer then has
to select one of the methods of fall protection if a fall hazard is present.
For example, if an employee is exposed to falling six feet or more from
an unprotected side or edge, the employer must select a guardrail
system, safety net system, or a personal fall arrest system to protect
the worker.
3. Employers must consider special occupations. Fall protection is
applicable to all workplaces, but employers must take into account
special considerations for different occupations. Work on electric utility
lines, for instance, differs from work on communication towers that are
sometimes as high as 1,000 feet, which again is quite different from
working on a residential roof. The use of the correct equipment for the
specific condition is extremely important.
Training
OSHA states that employers must provide a training program for employees
who are exposed to a fall hazard. The program must enable employees to
recognize the hazards of falling and must train them in the procedures for
minimizing hazards.
The employer must be sure that each employee has been trained by a
competent person in the following areas:
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Knowledge of Fall:
o Hazards
o Protection
o Physics
Employee Roles in:
o Safety monitoring systems
o Fall protection plan
o Employee supervision
Performance to:
o Select fall protection systems that are appropriate for the specific
job
o Implement and enforce safe work procedures/practices, enabling a
trainee to understand the different types of equipment available
and how to properly inspect the equipment on a daily basis
Procedure to:
o Erect, maintain, disassemble, and inspect fall protection systems
o Identify limitations on the use of mechanical equipment during the
performance of roofing work
o Handle and store equipment and materials
o Erect overhead protection
Retraining
OSHA also requires the retraining of employees if they do not have the proper
understanding and skills after initial training.
Other circumstances requiring retraining include:
Changes in the Workplace
If your job changes to:
• Working at an elevation as opposed to ground level
• Working around electrical hazards (power lines)
• Working with other trades both above and below you
Changes in the Use of Systems and Equipment
If your job changes to:
• Now using a positioning device instead of PFAS
• Now using guardrails as opposed to covers or PFAS
• Now using a fall protection plan or CAZ
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Now using a safety monitor instead of fall protection systems
Popups
Topic Summary
Please take a moment to review these major points before you continue with
the next topic.
• OSHA's rule states that employers must initiate a safety procedure when
workers are exposed to a fall hazard of six feet or more.
• The rule deals with both human and equipment-related issues such as
the need to know when protection is required and the proper installation
of safety systems.
• Safety monitoring systems, guardrails, warning lines, and safety nets
are a few of the many options employers have for protecting employees.
• Employers' steps to provide a fall protection plan are to (1) assess the
workplace, (2) select a method, and (3) consider special occupations.
• The goal of OSHA training is to enable employees to recognize and
minimize hazards.
• Fall protection training covers these areas: knowledge, performance,
procedures, and roles.
Topic 2: Fall Protection Coverage
Falls from elevation hazards are present at most every jobsite. Many workers
are exposed to these hazards daily. Any walking/working surface could be a
potential fall hazard. An unprotected side or edge, which is six feet or more
above a lower level should be protected from falling by the use of. These
hazardous exposures exist in many forms, and can be as seemingly innocuous
as a changing a light bulb form a step ladder to something as high-risk as
connecting bolt on high steel at 200 feet in the air.
Remember: Fall Protection strategies are required when workers are exposed
to a fall hazard of six feet or more above lower levels.
Risk Survey
You are aware that falls from elevations occur in all industries, in all
occupations, and in a myriad of work environments. From the ironworker
connecting steel columns 200 ft in the air, to the laborer washing windows
from a suspended scaffold 60 feet from the ground, to the stock clerk
retrieving goods from a shelf using a 4-ft stepladder, all workers performing
duties at an elevation are at risk to falls.
What else can contribute to fall risks?
There are many contributing factors for employees being at risk to falls.
It is important to recognizing that there are many risks, which are
contingent to the specific characteristics of each individual job-site.
Here are some other contributing factors:
• Lack of coordination of work tasks between contractors
• Rapid physical changes in the work environment
• Worker inexperience
• Deviation from standard operating procedures
• Lack of adherence to safety standards
• Employers lack of written task-specific work procedures
Topic Summary
Please take a moment to review this key point before you continue with the
next topic:
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Constant awareness of and respect for fall risks is important for all
workers exposed to working at an elevation.
OSHA has designated specific areas or activities where fall protection is
needed. These include, but are not limited to:
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Ramps, runways, and other walkways
Unprotected sides and edges
Excavations
Overhand bricklaying and related work
Hoist areas
Roofing work
Dangerous equipment
Precast concrete erection
Holes
Wall openings
Formwork and reinforcing steel
Residential construction
Leading-edge work
Other walking/working surfaces
Topic 3: Overview
Employers are required to provide fall protection for employees when they are
exposed to a fall of six feet or more to a walking or working surface.
Employers also are required to provide and install fall protection systems
before an employee begins any work that requires fall protection.
Hierarchy of Control
Reducing the risks associated with construction work is very important. To
meet this goal, there is a hierarchy or preferred order of control. These
controls are not mutually exclusive. There may be occasions when more than
one control must be used to reduce a risk. However, prevention would be best
served by implementing your hierarchy or control methodology before you
start any construction operation. The preferred order is presented in the
graphic.
Engineering Controls
Engineering controls, which attempt to eliminate hazards, do not necessarily
require an engineer to design them. Engineering controls can be very simple
To the extent feasible, the work environment and the job itself should be
designed to eliminate or reduce exposure to hazards based on the following
principles:
• If feasible, design the job site, equipment, or process to remove the
hazard or substitute something that is not hazardous or is less
hazardous.
• If removal is not feasible, enclose the hazard to prevent exposure in
normal operations.
• Where complete enclosure is not feasible, establish barriers to reduce
exposure to the hazard in normal operations.
Administrative Controls
Administrative controls are normally used in conjunction with other controls
that more directly prevent or control exposure to hazards. They include
lengthened rest breaks, additional relief workers, exercise breaks to vary body
motions, and rotating workers through different jobs to reduce stress or
repetitive motions on one part of the body. Administrative controls also include
introducing work practices that reduce the risk, by means including the
following:
• Limiting the amount of time a person is exposed to a particular hazard
• Implementing and documenting safe working procedures for all
hazardous tasks
• Training and instructing all personnel
• Identifying hazards prior to commencing work
Personal Protective Equipment
The last method of control is the use of PPE and should be considered only
when other control measures are not practicable or to increase a person's
protection as an additional measure. PPE includes:
• Hardhats
• Eye protection
• Fall-arrest harnesses and lanyards
• Foot protection
• Hand protection
• Respirators
• Hearing protection
Administrative and engineering controls can be used to eliminate fall hazards
before beginning operations. Personal protective equipment (PPE) as a
protection device is your last line of defense and protects you from fall
hazards.
Types of Fall Protection Systems
The selection of a fall protection system should match the particular work
situation. The types of fall protection options available for protecting
employees from fall hazards include:
• Personal fall arrest systems
• Guardrails
• Positioning device systems
• Warning lines
• Covers
• Safety monitoring systems
• Controlled access zones
• Safety nets
The kind of fall protection system selected should match the particular work
situation, and any possible free-fall distance should be kept to a minimum.
The employer should evaluate the work conditions and environment, including
the weather, before selecting the appropriate fall protection system.
You should also consider the particular work environment. If lanyards,
connectors, lifelines, or any fall protection system components are subject to
damage by work operations such as welding, chemical cleaning, and
sandblasting, the components should be protected.
Once in use, any type of fall protection system that you select to protect
employees from fall hazards needs to be monitored on a regular basis.
How do you protect falls to the same level? Housekeeping will do it.
Falls to the same level still cause a great number of incidents each year in the
construction industry. Such falls are caused primarily by the presence of
tripping hazards on the walking and working surfaces where employers are
performing their jobs.
While it is not commonly listed as a method of fall protection, the best way to
avoid, reduce, or eliminate tripping hazards is by implementing a job site
housekeeping program.
Topic Summary
Please take a moment to review these points before you continue with the
next topic.
• To reduce the risks associated with fall hazards engineering controls,
administrative controls, and PPE should be considered and used.
• The types of fall protection options available for protecting employees
from fall hazards include:
o Personal fall arrest systems
o Guardrails
o Positioning device systems
o Warning lines
o Covers
o Safety monitoring systems
o Controlled access zones
o Safety nets
Topic 4: Personal Fall Arrest Systems
Components of a Personal Fall Arrest System
The PFAS is designed to limit a free fall distance to six feet. The PFAS consists
of an anchorage point, a connector, lanyards, and a body harness.
Anchorage Points
Anchorage points must meet all the following criteria:
Independent of anchorages being used to support or suspend platforms
• Capable of supporting at least 5,000 pounds per employee
• Designed, installed, and used under the supervision of a qualified person
as part of a complete personal fall arrest system which maintains a
safety factor of at least two.
Note. Safety Factor: The ratio of the ultimate breaking strength of a
member or piece of material or equipment to the actual working stress or
safe load when in use
Body Harness
A body harness is a series of straps, which may be secured around an
employee in a manner that will distribute fall arrest forces over the thighs,
pelvis, waist, chest, and shoulders. Ropes and straps used in a body harness
must be made from synthetic fibers. The attachment point for a body harness
must be located in the center of the wearer's back near shoulder level.
A body harness and components used for employee protection are not to be
used to hoist materials. A PFAS should not be attached to hoists unless
specifically designed for that application.
Connector
The connector must meet the following criteria:
• Must be drop-forged, pressed, or formed steel, or made of equivalent
materials
• Must have a corrosion-resistant finish, and all surfaces and edges must
be smooth to prevent damage to interfacing parts of the PFAS
Lanyards
• Lanyards must have a minimum breaking strength of 5,000 pounds.
• They must automatically limit a free fall to two feet or less.
• They must be capable of sustaining a minimum tensile load of 3,000
pounds applied to the device with the lanyard in the fully extended
position.
• Lanyards that do not limit a free fall distance to 2 feet or less must be
capable of sustaining a minimum tensile load of 5,000 pounds applied to
the device with the lifeline in the fully extended position.
• Ropes and straps used in lanyards must be made of synthetic fibers.
What are the criteria for a PFAS used for fall protection?
The following is the criteria for a PFAS used for fall protection:
• Limit the maximum arresting force on an employee to 1,800 pounds
when used with a body harness
• Be rigged so that an employee can neither free fall more than six feet
nor contact any lower level
• Bring an employee to a complete stop and limit maximum deceleration
distance an employee travels to 3.5 feet
• Have sufficient strength to withstand twice the potential impact energy
of an employee free-falling a distance of six feet or the free-fall distance
permitted by the system, whichever is less
Other Components of a PFAS
A PFAS also may consist of a deceleration device, lifeline, or suitable
combination. A PFAS is not just one type of system. It can be composed of
different combinations depending on where it is being used and under what
circumstances.
Lifeline
A lifeline is a component consisting of a flexible line for connection to an
anchorage at one end to hang vertically (vertical lifeline), or for connection to
anchorages at both ends to stretch horizontally (horizontal lifeline). It serves
as a means for connecting other components of a personal fall arrest system
to the anchorage point.
The following are requirements for lifelines:
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Must have a minimum breaking strength of 5,000 pounds
Must be protected against being cut or abraded
Wire rope should not be used where an electrical hazard is anticipated.
Horizontal lifelines to be designed, installed, and used under supervision
of a qualified person
Horizontal lifelines as part of a complete personal fall arrest system
maintaining a safety factor of two
Each employee attached to a separate lifeline except when vertical
lifelines are used
On suspended scaffolds or similar work platforms with horizontal
lifelines, which may become vertical lifelines, devices used to connect a
horizontal lifeline must be capable of locking in both directions of the
lifeline
Ropes and straps used in lifelines must be made of synthetic fibers
Self-Retracting Lifelines
A self-retracting lifeline is a specific lifeline that:
• Automatically limits a free fall to two feet or less
• Must be capable of sustaining a minimum tensile load of 3,000 pounds
applied to the device with the lifeline in the fully extended position
• Self-retracting lifelines which DO NOT limit a free fall distance to 2 feet
or less must be capable of sustaining a minimum tensile load of 5,000
pounds applied to the device with the lifeline in the fully extended
position
Snaphooks
Locking snaphooks incorporate a positive locking mechanism in addition to the
spring-loaded keeper, which will not allow the keeper to open under moderate
pressure without someone first releasing the mechanism. Such a feature,
properly designed, effectively prevents roll-out.
The following connections must be avoided (unless properly designed locking
snaphooks are used) because they are conditions that can result in roll-out
when a nonlocking snaphook is used:
• Direct connection of a snaphook to a horizontal lifeline
• Two (or more) snaphooks connected to one D-ring
• Two snaphooks connected to each other
• A snaphook connected back on its integral lanyard
• A snaphook connected to a webbing loop or webbing lanyard
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Improper dimensions of the D-ring, rebar, or other connection point in
relation to the snaphook dimensions which would allow the snaphook
keeper to be depressed by a turning motion of the snaphook
Note: When sized to be compatible with the member to which they are
connected, to prevent unintentional disengagement or rollout, connections
is to be safe. Only locking-type snaphooks are permitted.
Body Belts
Body belts had been used like a body harness until January 1998 when the
use of a body belt as part of personal fall arrest system became prohibited.
However, body belts still can be used as part of a position device system if
allowed by OSHA.
Functional Categories of PFASs
The components of a PFAS have many functions to be used for fall arrest
system, positioning, and fall restraint system.
Fall Arrest
A fall arrest system is required if any risk exists that a worker may fall from an
elevated position. As a general rule, the fall arrest system should be used any
time a working height of six feet or more is reached. Working height is the
distance from the walking/working surface to a grade or lower level. A fall
arrest system will come into service only should a fall occur. A full-body
harness with a shock-absorbing lanyard or a retractable lifeline is the only
product recommended. A full-body harness distributes the forces throughout
the body, and the shock-absorbing lanyard decreases the total fall-arresting
forces.
Positioning
This system holds you in place while leaving your hands free to work.
Whenever the worker leans back, the system is activated. However, the
personal positioning system is not specifically designed for fall arrest
purposes.
Fall Restraint
A fall restraint system physically restricts or stops the employee before he or
she falls. A fall restraint system must meet the same requirements of both the
positioning and personal fall arrest systems.
PFAS Compliance
If an employee having a combined person and tool weight of less than 310
pounds is using the PFAS, the system will be considered to be in compliance.
If an employee having a combined person and tool weight of 310 pounds or
more is using the PFAS, the employer must modify the PFAS to meet the
criteria set by OSHA for protection for the heavier weight, or the PFAS will not
be deemed in compliance. In this case the competent person will provide for
or ask the PFAS manufacturer or supplier to provide a PFAS with
higher/greater weighted strength.
PFAS User Training
Careless or improper use of the equipment can result in serious injury or
death. Thorough employee training in the selection and use of personal fall
arrest systems is imperative.
Employees must be trained in the safe use of the system. This should include
the following:
• Application limits
• Proper anchoring and tie-off techniques
• Inspection and storage of the system
It is important for the employer and employee to know and understand the
reduction in strength caused by certain tie-offs (such as using knots, tying
around sharp edges, etc.). In addition to a determination of deceleration
distance and total fall distance to prevent striking a lower level, the employer
must know:
• Methods of use
• Estimation of free-fall distance
Employers and employees should become familiar with the manufacturer's
recommendations before using any system.
Inspection PFAS Equipment
A personal fall arrest system must be inspected prior to each use for wear
damage and other deterioration. For example, the presence of acids, dirt,
moisture, oil, grease, etc., and their effect on the system should be evaluated.
Hot or cold environments also may have an adverse effect on the system. Wire
rope should not be used where an electrical hazard is anticipated.
Key Point: A PFAS that has been subject to an impact load must be
immediately removed from service and not used for employee protection
until inspected and determined by a competent person to be undamaged
and suitable to reuse.
Body
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Harness Inspection
Begin at one end
Hold the body side of the belt toward you
Grasp the belt with your hands six to eight inches apart.
Bend the belt in an inverted "U."
Watch for frayed edges, broken fibers, pulled stitches, cuts, or chemical
damage.
Check D-rings and D-ring metal wear pads for distortion, cracks, breaks,
and rough or sharp edges.
Check that the D-ring bar should be at a 90-degree angle with the long
axis of the belt and should pivot freely.
Note any unusual wear, frayed or cut fibers, or distortion of the buckles.
Inspect frayed or broken strands. Broken webbing strands generally
appear as tufts on the webbing surface. Any broken, cut, or burnt
stitches will be readily seen.
Lanyard Inspection
When inspecting lanyards, begin at one end and work to the opposite end.
Slowly rotate the lanyard so that the entire circumference is visible. Spliced
ends require particular attention. Hardware should be examined under
procedures detailed below.
• Steel Lanyards: While rotating a steel lanyard, watch for cuts, frayed
areas, or unusual wear patterns on the wire. The use of steel lanyards
for fall protection without a shock-absorbing device is not recommended.
Wire rope should not be used where an electrical hazard is anticipated.
• Web Lanyard: While bending webbing over a piece of pipe, observe each
side of the webbed lanyard. This will reveal any cuts or breaks. Due to
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the limited elasticity of the web lanyard, fall protection without the use
of a shock absorber is not recommended.
Rope Lanyard: Rotation of the rope lanyard while inspecting from end to
end will bring to light any fuzzy, worn, broken, or cut fibers. Weakened
areas from extreme loads will appear as a noticeable change in original
diameter. The rope diameter should be uniform throughout, following a
short break-in period. When a rope lanyard is used for fall protection, a
shock-absorbing system should be included.
Shock-Absorbing Packs: The outer portion of the shock-absorbing pack
should be examined for burn holes and tears. Stitching on areas where
the pack is sewn to the D-ring, belt, or lanyard should be examined for
loose strands, rips, and deterioration.
Damage to Lanyards
• Chemical: Change in color usually appears as a brownish smear or
smudge. Transverse cracks appear when belt is bent over tightly. Such
cracks cause a loss of elasticity in the belt.
• Heat: In excessive heat, nylon becomes brittle and has a shriveled,
brownish appearance. Fibers will break when flexed and should not be
used above 180 degrees Fahrenheit.
• Molten Metal or Flame: Webbing and rope strands may be fused
together by molten metal or flame. Watch for hard, shiny spots or a
hard and brittle feel. Webbing will not support combustion while nylon
will.
• Paint and Solvents: Paint will penetrate and dry, restricting movement
of fibers. Drying agents and solvents in some paints will appear as
chemical damage.
• Ultraviolet Rays: Do not store webbing and rope lanyards in direct
sunlight, because ultraviolet rays can reduce the strength of some
material.
Care of PFASs
Basic care for fall protection safety equipment will prolong the life of the
equipment and contribute to the performance of its vital safety function.
Proper storage and maintenance after use is as important as cleaning the
equipment of dirt, corrosives, or contaminants. The storage area should be
clean, dry, and free of exposure to fumes or corrosive elements.
PFAS Components Made of Nylon and Polyester
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Wipe off all surface dirt with a sponge dampened in plain water
Squeeze the sponge dry
Dip the sponge in a mild solution of water and commercial soap or
detergent
Work up a thick lather with a vigorous back and forth motion
ipe the belt dry with a clean cloth
Hang freely to dry but away from excessive heat.
Drying
Harness, belts, and other equipments should be dried thoroughly without
exposure to heat, steam or long periods of sunlight.
How To Wear a PFAS
One of the most important aspects of a complete fall protection program is
properly donning a body harness and its components.
1. Hold harness by back D-ring. Shake harness to allow all straps to fall
into place.
2. In chest, leg and/or waist straps are buckled, release straps and
unbuckle at this time.
3. Slip straps over shoulders so D-ring is located in middle of back between
shoulder blades.
4. Pull leg strap between legs and connect to the opposite end. Repeat with
second leg strap. If belted harness, connect waist strap after leg straps.
Waist strap should be tight, but not binding.
5. Connect chest strap and position in mid-chest area. Tighten to keep
shoulder straps taut.
6. After all straps have been buckled, tighten all buckles so that the
harness fits snug but allows full excess strap through loop keepers.
Planning the System
One of the most important aspects of personal fall protection systems is fully
planning the system before it is put into use. A PFAS is not fool-proof there are
a number of potential hazards, such as the following:
Proper clearance/Swing
The location of the anchorage point also should consider the hazard of
obstructions in the potential fall path of the employee. Anchorage points,
which minimize the possibilities of exaggerated swinging, also should be
considered.
Obstructions that might interfere with the free fall should be avoided or a
severe injury could occur. A swing fall can be as harmful as falling to the
ground.
PFAS not Properly Worn
If you don't wear PFAS properly it can be as bad as not wearing PFAS at all. All
PFAS are designed to protect the wearer if they fall. If you wear the PFAS too
loose there is the potential for additional stress and strain on the PFAS and the
wearer if the system is to be used. In addition, there is the potential to get
caught on something be torn or damaged which may create an additional fall
hazard. If you wear the PFAS too tight it can create circulation problems,
which can lead to premature muscle fatigue and the potential for slips or falls.
Mixing Components/Roll-Out
A PFAS is designed, tested, and supplied as a complete system. However it is
common practice for lanyards, connectors, lifelines, deceleration devices, and
body harnesses to be interchanged because some components wear out
sooner than others.
Components from different manufacturers can create a numbers of hazards
including roll-out wear a single action snap hook is improperly mated to an
attachment point or another component, allowing an opportunity for the snap
hook to be opened by the attachment or component, thus allowing the PFAS to
be disengaged and exposing the wearer to an unprotected fall.
No component of a PFAS should be substituted or changes unless fully
evaluated and tested by a competent person or equipment manufacturer.
Prolonged Suspension
As part of a comprehensive fall protection program the employer must develop
a system of rescue or retrieval even if it is self-rescue or retrieval. An
individual that has falling while wearing a PFAS must be removed from the
system immediately to prevent any further bodily damage. The PFAS is
designed to reduce the force on the body as the fall is arrested but the system
is not designed for a prolonged stay after the fall.
The body harness as part of a PFAS helps to eliminate some of the issues
associated being suspended by spreading the force of a fall across the body.
Previously, the body harness was used extensively in the construction
industry. The problem with the body harness was if the wearer did fall the
body harness would create a great deal of force on the wearers' mid section
thus creating secondary injuries to the back and internal organs from the fall.
Tripping/Entanglement
Some individuals get used to wearing a PFAS immediately while others
struggle with getting used to it. A PFAS is a system that has numerous
components, which may change from day to day, or job to job and depending
upon the situation or circumstances it is being used for. Regardless how you
feel about wearing a PFAS, there is always a potential for tripping or
entanglement. Being too worried about the PFAS tends to take the wearer's
mind off the job at hand always watching or minding his/her PFAS while an
individual who is too comfortable with the PFAS may tend to complacent and
forgets the environment the PFAS components are being exposed to such as,
sharp edges and other individuals PFAS or equipment.
Planning for suitable anchorage points
Probably the most overlooked component is planning for suitable anchorage
points. Such planning ideally should be done before the structure or building is
constructed so that anchorage points can be incorporated during construction
for use later in window cleaning or other building maintenance. If properly
planned, these anchorage points may be used during construction, as well as
afterwards.
Topic Summary
Please take a moment to review these points before you continue with the
next topic.
• A PFAS consists of an anchorage point, a connector, and a body harness
and may also consist of a deceleration device, lifeline (pop-up), or
suitable combinations thereof.
• The components of a PFAS have many functions to be used for fall arrest
system, positioning, and fall restraint system.
• If an employee with a combined person and tool weight of 310 pounds
or more is using the PFAS, the employer must modify the PFAS to meet
the criteria set by OSHA for protection for the heavier weight.
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A PFAS that has been subject to an impact load must be immediately
removed from service and not used for employee protection until
inspected and determined by a competent person to be undamaged and
suitable to reuse.
Proper storage and maintenance of a PFAS after use is as important as
cleaning the equipment of dirt, corrosives, or contaminants. The storage
area should be clean, dry, and free of exposure to fumes or corrosive
elements.
The location of the anchorage point also should consider the hazard of
obstructions in the potential fall path of the employee.
When mixing components, the employer and employee should realize
that not all components are interchangeable.
Topic 5: Guardrail Systems
In this topic you will learn about guardrail systems. A guardrail system is one
of the most common forms of fall protection in the construction industry. Upon
completing this topic, you will be able to:
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Describe specifications of a guardrail system including toprail, midrail,
and toeboard
Recall criteria required for guardrail systems
Explain special guardrail provisions
List different types of guardrails and describe their requirements
Components of Guardrail Systems
A guardrail system is one of the most common forms of fall protection in the
construction industry.
A guardrail system is comprised of a toprail and a midrail. Where there is
potential for falling objects, a toeboard also is required as part of the guardrail
system.
Toprail
• The top edge height of toprails must be 42 inches 3 inches above a
walking/working surface.
• When employees are using stilts, the top edge height of the toprail must
increase an equal amount to the height of the stilts
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The toprail must be capable of withstanding a force of at least 200
pounds applied within 2 inches in any downward or outward direction.
When the test is applied in a downward direction, the toprail must not
deflect to a distance less than 39 inches above the walking/working
surface.
Midrails
• Midrails should be halfway between the top edge of the guardrail and
the walking/working surface. The only exception to using a midrail is
when a wall or parapet comes up at least 21 inches next to the
guardrail; then the wall provides the necessary protection.
• Midrails, screens, mesh, intermediate vertical members, or equivalent
intermediate structural members must be installed between the
toprail and the walking/working surface when there are no walls or
parapet walls at least 21 inches high.
• When screens and mesh are used, they must extend from the toprail
to the walking/working surface and along the entire opening between
the toprail vertical supports.
• Intermediate members such as balusters, when used between posts,
must not be more than 19 inches apart.
• Midrails, screens, mesh, intermediate vertical members, or equivalent
intermediate structures must be capable of withstanding a force of a
least 150 pounds in any downward or outward direction at any point
along the midrail or other member.
Toeboards
• As part of a guardrail system, the primary function of toeboard is to
provide protection from falling objects.
• Toeboards must be capable of withstanding a force of a least 50 pounds
in any downward or outward direction at any point along the toeboard.
• Toeboards must be at least 31/2 inches high from their top edge to the
walking/working surface. Toeboards cannot be more than 1/4 inch above
the walking/working surface. Toeboards cannot have openings greater
than 1 inch at their largest dimension.
• Where tools, equipment, or materials are piled higher than the top edge
of the toeboard, paneling or screening must be erected from the
walking/working surface to the toprail or midrail, whichever is sufficient
to protect employees below.
What are the criteria that guardrail systems must meet?
1. Use materials with a smooth surface that won't cause cuts or snag
clothing and possibly cause a fall.
2. Guardrails should be strong enough to withstand a force of up to 200
pounds applied in any outward or downward direction.
3. Steel and plastic banding cannot be used as toprails or midrails.
4. Manila, plastic, or synthetic rope used for toprails or midrails must be
inspected as frequently as necessary to ensure strength and stability.
These may be the least desirable because they have to be inspected
often and may deteriorate rapidly.
5. Guardrail systems must not overhang their terminal posts and create a
projection hazard.
6. Wood, pipe, structural steel, and cable (wire rope) are all good materials
for constructing guardrails.
Note: Where possible, you should first consider installing guardrails or
barriers. They provide a high degree of protection once installed properly. In
the construction industry, however, installing guardrails or barriers is not
always practical; in that instance you will need personal fall protection
equipment.
Special Guardrail Provisions
When a guardrail system is used at a hoisting area, a chain, gate, or
removable guardrail section must be placed across the hoist access opening
when hoisting operations are not taking place.
When a guardrail system is used around holes, the system must be set up on
all unprotected sides. When holes are used to pass material, the hole cannot
have more than two sides that are removable. When the hole is not in use it
must be covered or provided with guardrails on all sides. When holes are used
for access points for ladders or stairways, gates must be used or the point of
access must be offset to prevent employees from walking into the hole.
If guardrails are used on unprotected sides or edges of ramps, runways, or
other walkways, they must be erected on each side or edge.
Types of Guardrails
There are different types of guardrails based on the material used. Click each
image to see its requirements.
Wood Guardrails
When using wood, choose stress-grade construction lumber. The following
requirements must apply:
1. Posts are at least 2-inch by 4-inch lumber, spaced not more than 8 feet
apart on centers.
2. Toprails are at least 2-inch by 4-inch lumber.
3. Intermediate rails are at least 1-inch by 6-inch lumber.
Pipe Guardrails
Pipe components are required to meet the following criteria:
1. Posts are at least 11/2 inches in nominal diameter (schedule 40 pipe),
spaced not more than 8 feet apart on centers.
2. Toprails are at least 11/2 inches nominal diameter (schedule 40 pipe).
3. Intermediate railings are at least 11/2 inches nominal diameter
(schedule 40 pipe).
Structural Steel Guardrails
Structural steel components are required to meet the following criteria:
1. Posts are at least 2-inch by 2-inch by 3/8-inch angles, with posts spaced
not more than 8 feet apart on center.
2. Toprails are at least 2-inch by 2-inch by 3/8-inch angles.
3. Intermediate rails are at least 2-inch by 2-inch by 3/8-inch angles.
Wire Rope Guardrails
1. Wire rope guardrails have no requirement that terminal supports be
maintained at 8 feet on center, but when tested in the center with the
200-pound force the toprails must not deflect below 39 inches from the
walking/working surface.
2. Toprails and midrails of a guardrail system must be at least 1/4 inch
nominal diameter or thickness to prevent cuts and lacerations.
3. If wire rope is used for toprails, it must be flagged with high-visibility
material at intervals not more than 6 feet.
Topic Summary
Please take a moment to review these points before you continue with the
next topic.
• A guardrail system is composed of a toprail and a midrail. Where there is
potential for falling objects, a toeboard also is required as part of the
guardrail system.
• Guardrails should be strong enough to withstand a force of up to 200
pounds applied in any outward or downward direction.
• When a guardrail system is used at a hoisting area, a chain, gate, or
removable guardrail section must be placed across the hoist access
opening when hoisting operations are not taking place.
• Four different types of guardrails based on the material used are wood
guardrails, pipe guardrails, structural steel guardrails, and wire rope
guardrails.
Topic 6: Positioning Device Systems, Warning Lines Systems, and
Covers
In this topic you will learn about warning lines systems, positioning device
systems, and covers. A warning line system is a barrier that is erected to warn
employees that they are approaching an unprotected roof side or edge. A
positioning device system allows you to be supported on an elevated vertical
surface. Employees must be protected from falling into or through holes by
hole covers.
Upon
•
•
•
completing this topic, you will be able to:
State the requirements for warning lines systems
Describe requirements for positioning device systems
List criteria required for covers for holes in floors, roofs, and other
walking/working surfaces
Positioning Device Systems
A positioning device system is a body belt or body harness system rigged to
allow an employee to be supported on an elevated vertical surface, such as a
wall, and to work with both hands free while leaning.
Body Belts
Since January 1998, the use of a body belt as part of PFAS has been
prohibited. However, body belts still can be used as part of a position device
system if allowed by OSHA. Body belts are prohibited because the body
harness was shown in studies to limit the trauma on the body during a fall. A
body belt focuses all of the force on the center of the body, while a body
harness disperses the energy throughout the torso area. For this reason,
OSHA concluded that body harnesses provided a higher level of protection.
Ropes and straps used in body belts must be made of synthetic fibers. Body
belts must be at least 1 5/8 inches wide. The attachment point for a body belt
must be in the center of the wearer's back.
A body harness or body belt as part of a positioning device system is to be
installed so an employee can free fall no farther than two feet (two feet for a
positioning device vs. six feet for a PFAS, due to the fact that it is only a
positioning device not made for any other function within construction
operations).
The positioning device system's anchorage point must be capable of
supporting at least twice the potential impact load of an employee's fall or
3,000 pounds, whichever is greater. A positioning device is to stop your fall
within two feet, so this allows the anchorage point to be reduced to 3,000
pounds as opposed to 5,000 pounds for a PFAS.
Note. The components of a PFAS are also some of the same components
of restraint systems and positioning systems. Some components are
being used for a different function.
Requirements for Positioning Device Systems
All positioning device system components including snaphooks and d-rings
must meet the same criteria as personal fall arrest systems. Among those
criteria:
• Connecting assemblies have a tensile strength of 5,000 pounds
• Positioning device systems must be drop-forged, pressed, or formed
steel, or made of equivalent materials
• Systems must have a corrosion-resistant finish, and all surfaces and
edges must be smooth to prevent damage to interfacing parts of the
PFAS
•
•
•
D-rings and snaphooks must be proof-tested to a minimum tensile load
of 3,600 without cracking, breaking, or taking permanent deformation
Snaphooks must be sized to be compatible with the member to which
they are connected to prevent roll-out, or a locking type snaphook must
be designed and used to prevent disengagement of the snaphook.
Body harnesses, body belts, and components must not be used to hoist
materials
Key Point: Positioning device systems must be inspected prior to each use for
wear, damage, and other deterioration, and defective components must be
removed from service.
Warning Lines Systems
A warning line system is a barrier that is erected to warn employees that they
are approaching an unprotected roof side or edge. It designates an area in
which roofing work may take place without the use of guardrail, body belt, or
safety net systems to protect employees in the area.
Warning lines systems must meet the following criteria:
1. A warning line will be erected around all sides of the roof work area.
2. When mechanical equipment is not being used, warning lines will be not
less than six feet from the roof edge.
3. When mechanical equipment is being used, warning lines will not be less
than 6 feet from the roof edge parallel to the direction of mechanical
equipment operations, and not less than 10 feet from the roof edge
perpendicular to direction of mechanical operations.
4. Points of access, materials handling areas, storage areas, and hoisting
areas will be connected to the work area by an access path formed by
two warning lines.
5. When the path to a point of access is not in use, a rope, wire, chain, or
other barricade equivalent in strength and height to the warning line is
placed across path at the point where the path intersects the warning
line erected around work area, or the path is offset so a person cannot
walk directly into the work area.
What are the criteria for the warning line?
1. Rope, wire, or chain flagged at not more than 6-foot intervals with highvisibility material
2. Rigged and supported so the lowest point is not less than 34 inches and
the highest point not more than 39 inches from the walking/working
surface
3. With lines attached, stanchions must be capable of resisting, without
tipping over, a force of at least 16 pounds applied horizontally against
the stanchion, 30 inches above walking/working surface, perpendicular
to warning line, and in the direction of floor, roof, or platform edge
4. Rope, wire, or chain must have a minimum tensile strength of 500
pounds
5. Lines attached at each stanchion in such a way that pulling on one
section of line between stanchions will not result in the slack being taken
up in adjacent sections before the stanchion tips over
6. Wire rope not used where an electrical hazard is anticipated
Covers
Employees must be protected from falling into or through holes, including
skylights that are six feet or more above lower levels. One way to guard
against this hazard is the placement of hole covers.
Covers for holes in floors, roofs, and other walking/working surfaces should
meet the following criteria:
• Covers located in roadways and vehicular aisles must be able to support
at least twice the maximum axle load of the largest vehicle to which the
cover might be subjected.
• All other covers must be able to support at least twice the weight of the
employee, equipment, and materials that may be imposed on the cover
at any time.
• To prevent incidental displacement resulting from wind, equipment, or
employee activity, all covers must be secured.
• All covers should be color-coded or bear the marking "HOLE" or "COVER"
to provide warning of the hazard.
• If plywood is used to cover holes, it should be at least 3/4 of an inch
thick.
• Install the covers so as to eliminate any tripping hazards.
Topic Summary
Please take a moment to review these points before you continue with the
next topic.
• A warning line system is a barrier erected to warn employees that they
are approaching an unprotected roof side or edge. It designates an area
in which roofing work may take place without the use of guardrail, body
belt, or safety net systems to protect employees in the area.
• A positioning device system is a body belt or body harness system
rigged to allow an employee to be supported on an elevated vertical
surface, such as a wall, and work with both hands free while leaning.
• Employees must be protected from falling into or through holes by
placing hole covers. Covers should support at least twice the weight of
the employee, equipment, materials, and the maximum axle load of the
largest vehicle to which the cover might be subjected.
Topic 7: Safety Monitoring Systems, CAZ, and Safety Nets
In this topic, you will learn about safety monitoring systems, controlled access
zone, and safety nets. A safety monitoring system is a passive safety system
where the competent person is responsible for recognizing and warning
employees of fall hazards. A controlled access zone (CAZ) is an area in which
certain work may take place without use of guardrail systems, personal fall
arrest systems, or safety nets. Safety nets are another conventional fall
protection system that employers may use to protect employees from falls.
Upon completing this topic, you will be able to:
• Explain how safety monitoring systems can protect you from falling
• Describe requirements for the control lines and controlled access zone,
including areas where overhand bricklaying operations are taking place
• State the requirements for controlled access zone
• State the requirements for safety nets
• Explain how to test safety nets
A safety monitoring system is a passive safety system where the competent
person is responsible for recognizing and warning employees of fall hazards.
Workers are not protected by other fall protection systems when using a
safety monitor. The safety monitor works on the same level as the employees
who have to be protected and provides verbal warnings to those employees
whenever they are approaching the area of a hazard.
When using a safety monitoring system, the following requirements apply:
• A competent person is designated to monitor the safety of other
employees. The safety monitor must be competent to recognize fall
hazards.
• The safety monitor will warn employees when it appears the employees
are unaware of a fall hazard or they are acting unsafely.
• The safety monitor will be on the same surface within visual sighting
distance of employees being monitored.
• The safety monitor will be close enough to communicate orally with
employees.
• The safety monitor will not have any other responsibilities that could
take the monitor's attention away from monitoring.
Controlled Access Zone
A controlled access zone (CAZ) is an area in which certain work may take
place without the use of guardrail systems, personal fall arrest systems, or
safety net systems. Access to the zone is controlled.
Controlled access zones are often used in conjunction with a safety monitoring
system.
When a controlled access zone is in use, the following requirements have to be
met:
• When used to control access to areas where leading edge and other
operations are taking place, the controlled access zone must be defined
by a control line or other means that restrict access.
• Control lines must be between 6 feet and 25 feet from the unprotected
or leading edge, except when erecting precast concrete members.
• When erecting precast concrete members, control lines can be erected
not less than 6 feet nor more than 60 feet or half the length of the
member being erected, whichever is less, from the leading edge.
• Control lines are to be extended along the entire length of the
unprotected or leading edge, approximately parallel to the unprotected
or leading edge.
• Control lines are connected on each side to a guardrail system or a wall.
What are the criteria for the control line?
The control lines used to designate controlled access zones can consist of
ropes, wires, tapes, or equivalent materials and supporting stanchions that
meet the following requirements:
• Lines are flagged or clearly marked at six-foot intervals with highvisibility material.
• Each line is rigged and supported so that it is not less than 39 inches
and not more than 45 inches from the walking/working surface.
• Each line is rigged and supported so that it is not less than 39 inches
and not more than 50 inches from the walking /working surface when
overhand bricklaying operations are being performed.
• Each line must have a minimum breaking strength of 200 pounds.
CAZ With Overhand Bricklaying Operations
When a CAZ is used to control access to areas where overhand bricklaying and
related work are taking place, the following requirements must apply:
• The controlled access zone is defined by a control line erected not less
than 10 feet nor more than 15 feet from the working edge.
• Control lines must extend to enclose all employees performing overhand
bricklaying and related work at the working edge and should be parallel
to the working edge.
• Additional control lines are to be erected at each end to enclose the
controlled access zone.
• Only employees engaged in overhand bricklaying or related work are
permitted in the controlled access zone.
On floors and roofs where guardrail systems are not in place prior to beginning
of overhand bricklaying operations, the controlled access zones must be
enlarged to enclose all points of access, material handling areas, and storage
areas.
On floors and roofs where guardrail systems are in place but need to be
removed to allow for overhand bricklaying work or leading edge work, only the
portion of the guardrail necessary to accomplish that day's work may be
removed.
Safety Nets
A safety net system is another conventional fall protection system employers
may use to protect employees from falls.
The following requirements apply to the use of safety nets:
• Safety nets must be installed as close as possible under the
walking/working surface on which employees are working and never
more than 30 feet below this level.
• Safety net systems must extend outward from their outermost
projection.
• Safety net systems must be installed with sufficient clearance to prevent
contact with surface or structures below when subjected to an impact
force.
• The maximum size of each safety net mesh opening cannot exceed 36
square inches; nor can it be longer than 6 inches on any side.
• All mesh crossings must be secured to prevent enlargement of the
openings.
• Each safety net system must have a broader rope for webbing with a
minimum breaking strength of 5,000 pounds.
• Connections between safety net panels must be as strong as the integral
net components and cannot be spaced more than six inches apart.
In addition to these requirements, the employer must be sure that materials,
scrap pieces, equipment, and tools that have fallen into a safety net are
removed as soon as possible and at least before the next work shift.
Safety nets and their installation must be drop-tested:
• After initial installation
• Before initial use as fall protection
• Whenever relocated
• After a major repair
• At six-month intervals if left in one place
Safety nets must be tested with a 400-pound bag of sand (30 2 inches in
diameter) dropped into the net from the highest walking/working surface from
which an employee can fall.
The drop test must never be performed from less than 42 inches.
When it is unreasonable to perform the drop test, the employer or designated
competent person must certify the net is capable of providing worker
protection.
The most recent certification record for each safety net system must be
available at the job site.
Other requirements include:
• Safety nets systems must be inspected at least once a week for wear,
damage, and other deterioration.
• Defective nets must not be used.
• Defective components must be removed from service.
• Safety net systems also will be inspected after any occurrence that could
affect their integrity.
Topic Summary
Please take a moment to review these points before you continue with the
next topic.
• The safety monitor works on the same level as the employees who have
to be protected and provides oral warnings to those employees
whenever they are approaching the area of a hazard.
• A controlled access zone (CAZ) is an area in which certain work may
take place without use of guardrail systems, personal fall arrest
systems, or safety net systems.
• The controlled access zone is defined by a control line.
• Safety nets must be installed as close as possible under the
walking/working surface on which employees are working and never
more than 30 feet below this level.
• Safety net testing is required in the following situations:
o After initial installation
o Before initial use as fall protection
o Whenever relocated
o After a major repair
o At six-month intervals if left in one place
Topic 8: Fall Protection Plans
Remember the following criteria for situations in which a fall protection plan is
implemented:
1.
Fall protection plans are prepared and developed by a qualified
person specifically for the site where leading edge work, precast
concrete work, and residential construction are being performed.
2.
The fall protection plan must be kept up to date.
3.
A qualified person approves changes to the fall protection plan.
4.
A copy of the fall protection plan with approved changes is
maintained at the job site.
5.
Implementation of the fall protection plan is under the supervision of
a competent person.
6.
Fall protection plans must document the reasons why use of
conventional fall protection systems (guardrails systems, personal fall
arrest systems, or safety net systems) are infeasible or why their use
would create a greater hazard.
7.
The plan must include a written discussion of other measures to be
taken to reduce or eliminate fall hazards for employees who cannot
be provided with protection from conventional fall protection systems.
8.
The plan must identify each location where convention fall protection
methods cannot be used. These locations are classified as controlled
access zones (CAZ).
9.
The plan must include a statement that provides the name or other
method of identification for each employee designated to work in
controlled access zones. No other employee may enter controlled
access zones.
10. Where no other alternative measure has been implemented, the
employer must implement a safety monitoring system.
11. In the event an employee falls or some other related, serious incident
occurs (near-miss), the employer will investigate the circumstances
of the fall or other incident to determine if the fall protection plan
needs to be changed (new practices, procedures, or training) and
must implement those changes to prevent similar types of falls or
incidents.
Falling Object Protection Plans
Remember the following criteria for situations in which fall protection must be
considered to protect workers from overhead hazards:
• A hardhat must be worn.
•
•
•
•
•
•
•
A guardrail system including a toeboard can be used as falling object
protection.
No material or equipment, excluding mortar and masonry, can be stored
within four feet of working edges.
Excess mortar, broken or scattered masonry units, and all other
materials and debris must be kept clear of the working area by removal
at regular intervals.
During roofing operations, materials and equipment cannot be stored
within six feet of a roof edge unless guardrails are erected at the roof
edge.
Roofing materials piled, grouped, or stacked near a roof edge must be
stable and self-supporting.
You also can use canopies strong enough to resist collapse and resist
penetration by any object that may fall onto them.
Barricade the area to which objects could fall and prohibit employees
from entering the barricaded area.
Topic Summary
Please take a moment to review these points before you continue with the
next topic.
• The fall protection plan should be prepared, developed, and approved by
a qualified person.
• Implementation of the fall protection plan is under the supervision of a
competent person.
• Fall protection plans must document the reasons why use of
conventional fall protection systems are infeasible or why their use
would create a greater hazard.
• Where no other alternative measure has been implemented, the
employer must implement a safety monitoring system.
• A hardhat must be worn and a guardrail system including a toeboard can
be used as protection against falling objects.
• Barricade the area to which objects could fall and prohibit employees
from entering the barricaded area.
Topic 9: Fall Protection Training Program
This topic covers training program specifications required for fall protection.
Upon completing this topic, the student will be able to:
• Describe training requirements and training topics
• State what should be included in a certification of training
• Identify when to take a fall protection training
Training Requirements, Topics, Certification, and Frequency
There are things you need to know about fall protection training.
Training Requirements
Training requirements for fall protection training programs are:
• The employer has to provide a training program for each employee who
might be exposed to fall hazards.
• The training program must enable each employee to recognize the
hazards of falling.
• The training program must train each employee on procedures that will
help minimize fall hazards.
• The training program has to be conducted by a competent person.
• The training program must take into account the bilingual workforce.
Training Topics
The following list includes topics covered in the fall protection training
program:
• Nature of fall hazards
• Correct procedures to select, erect, maintain, disassemble, and inspect
fall protection systems
• Proper use of fall protection systems
• The use and operation of guardrail systems, personal fall arrest systems,
safety net systems, warning line systems, safety monitoring systems,
controlled access zones, and other protection
• Limitations of fall protection systems
• Procedures for proper handling and storage of fall protection systems
• Job site-specific issues like anchorage points, clearance, and
identification of the competent person
Certification of Training
Fall protection training requires a certification, which includes the following:
• Employees name
• Date of training
•
Signature of trainer
Training Frequency
A fall protection training program requires training in any of the following
situations:
• Initial employment
• Changes in the workplace
• Changes in the type of fall protection system used
• Inadequate previous training
Topic Summary
Please take a moment to review these points before you continue with the
next topic.
• The employer has to provide a training program for each employee who
might be exposed to fall hazards.
• The training program must train each employee on procedures that will
help minimize fall hazards.
• Fall protection training requires a certification, which includes the
employee's name, date of training, and signature of trainer.
• Training should take place when initial employment begins, with changes
in the workplace or in the type of fall protection system used, and when
previous training has been inadequate.
Lesson Summary
This lesson contains information and instruction about fall protection. By
completing this lesson, you should have the knowledge to discuss the following
topics. Take a moment to see if you can do the following:
• Discuss the historical progression of fall protection safety in the
workplace
• Define OSHA's fall protection rule and explain the employer's
responsibility to provide fall protection
• Outline OSHA's fall protection training program requirements
• Recognize the risks at working at elevations
• Identify activities for which fall protection is needed and select applicable
safeguards
• Explain hierarchy of control and identify fall protection system options
•
•
•
•
•
•
Describe components of personal fall arrest systems and how to inspect,
wear, and care for the systems
Describe components of a guardrail system and the types of guardrails
Distinguish when and how to use positioning device systems, warning
lines systems, and covers
Determine when and how to use safety monitoring systems, controlled
access zone, and safety nets
State the fall protection plan requirements, including falling object
protection plans
State fall protection training requirements, topics, and requirements for
a certification. Identify situations where you need to provide fall
protection training
Cranes
Introduction
Today's skylines are constantly changing, and the masts of cranes are always part of
the picture.
There are approximately 125,000 cranes in operation today in the construction
industry, as well as an additional 80,000-100,000 in general and maritime industries.
More than 250,000 crane operators and a very large but undetermined number of
other workers and the general public are at risk of serious and often fatal injury due
to accidents involving cranes, derricks, hoists, and hoisting accessories.
OSHA reports that cranes are involved in 25 to 33 percent of fatal injuries, an
average of 71 fatalities each year.
Lesson Overview
Welcome to the "Cranes" lesson of the Turner OSHA Certification course. Upon
completing this lesson, you will be able to:
• Identify general information and requirements when working with cranes
• Identify the different types of cranes and derricks, and implement safe work
practices
• Explain the four principles of crane lifting and describe crane operating
standards
• Determine the safety precautions for using all associated lifting equipment
Why Learn This Lesson?
OSHA has identified the major causes of crane accidents to include boom or crane
contact with energized power lines (nearly 45 percent of the cases), under-the-hook
lifting device, overturned cranes, dropped loads, boom collapse, crushing by the
counterweight, outrigger use, falls, and rigging failures.
Some cranes are neither maintained properly nor inspected regularly to ensure safe
operation. Many crane operators do not have the necessary qualifications to operate
each piece of equipment safely, and the operator qualifications required in the
existing regulations may not provide adequate guidance to employers. The table
below listing a typical employer's annual cited violations reflects the need to
continually examine crane safety.
This lesson is important because cranes and associated lifting machinery can be one
of the most dangerous types of equipment on the job site. OSHA, employers, and
their employees all must be aware of the precautions necessary to work with cranes
safely.
Topic 1: General Information
This topic introduces general information and requirements for working with cranes.
You will review OSHA standards, the hierarchy of control principles, and the
Preplanning Checklist.
Upon completing this topic, you will be able to do the following:
•
•
•
Identify OSHA's standards for crane use at the workplace
Implement the hierarchy of control principles within your work environment
Use the Preplanning Checklist to discuss safety requirements prior to the lift
Standards
Crane and lifting incidents are costly not only financially but also emotionally. An
obvious first step in preventing fatalities and serious injuries is to ensure that all such
operations be done only in at least minimal compliance with existing OSHA standards.
The primary areas of concern for which OSHA is reviewing include:
•
•
•
•
•
Criteria for operator qualifications
Standard update
Clarification of use
Inspection and maintenance of cranes
Certification or qualifications of riggers and signal persons
In addition to OSHA standards, many employers adopt standards from these agencies
to reduce safety risks:
• American National Standards Institute (ANSI)
• American Society of Mechanical Engineers (ASME)
• Specialized Carriers and Riggers Association (SC&RA)
• Crane and Hoist Safety
Crane and Hoist Safety
Crane and Hoist Safety sets criteria for designation as an OSHA priority. The very
serious nature of the hazard, the magnitude of the risk (high rate of fatalities and
serious injuries relative to the number of workers exposed), the potential for
catastrophic accidents, and the considerable knowledge about effective protective
measures clearly demonstrate the need for action to address crane and hoist safety
Preplanning
Each crane's operating procedures must be reviewed, discussed, and communicated
well in advance of the actual lift.
Preplanning Checklist
• Timing of equipment delivery
• Staging and setup
• Rubber or outriggers
• Retracted or extended
• Rubber of stabilizers
• Ground stability
• Previously disturbed
• Trenches and excavations
• Backfilled
• Soil conditions
• Outriggers
• Pads
• Pinning
• Blocking
• Materials
• Size
• Direction
• Ground pressure
• Leveling
• Setting up
• Side loading
• Rigging
• Inspections
• Equipment
• Wire rope
• Nylon slings
• Chokers
• Clamps
• Spreaders
• Reeving
•
•
•
2-Part
4-Part
Anti-Two Block Device
Topic Summary
Please take a moment to review these major points before you continue with the next
topic.
• OSHA's primary concerns in establishing crane standards include:
o Criteria for operator qualifications
o Standard update
o Clarification of use
o Inspection and maintenance of cranes
o Certification or qualifications of riggers and signal persons
•
•
•
In addition to OSHA standards, employers adopt crane standards developed
by:
o American National Standards Institute (ANSI)
o American Society of Mechanical Engineers (ASME)
o Specialized Carriers and Riggers Association (SC&RA)
o Crane and Hoist Safety
The preferred order of control is (1) engineering, (2) administration, and (3)
personal protective equipment.
Prior to a lift, use the Preplanning Checklist to confirm the proper operating
procedures.
Topic 2: Types of Cranes
Overview
This topic describes the different types of cranes, derricks, and helicopters and lists
OSHA's requirements for their safe use. Upon completing this topic, you will be able
to:
•
•
•
•
List the six different types of cranes and give examples of each
State the safety requirements for floating cranes and derricks
Explain the regulations applying to operating helicopter cranes
Comply with the five general requirements for working with cranes and derricks
Cranes
Moving large, heavy loads is crucial to today's construction industry. Much technology
has been developed for these operations, as well as careful training and extensive
workplace precautions. There are significant safety issues to be considered, both for
operators of the diverse lifting devices and for workers in proximity to them. First you
will identify the different types of cranes and derricks, and then you will read about
OSHA's requirements for crane safety.
There are six standard types of machines for hoisting heavy objects.
•
•
•
•
•
•
Hoisting Machines
Boom Trucks (Threscopine Boom and Articulating Boom)
Truck Cranes (Lattice Boom and Telescopic)
Crawlers Cranes (Lattice Boom and Telescopic)
Rough Terrain Cranes (Fixed Lab and Rotting Cab)
Mobile Tower Cranes (Crawler Mounted and Carrier Mounted, Heavy Lift Cranes
and Rolling Ring and Crawler)
The six types of cranes described are categorized by three functions: mobile, fixed,
and overhead cranes.
Crawler, Locomotive, and Truck Cranes
•
All jibs must have positive stops to prevent their movement of more than 5°
above the straight line of the jib and boom on conventional crane booms.
•
The use of cable type belly slings is not permitted.
•
There must be a certification record, which includes the date the crane items
were inspected; the signature of the person who inspected the crane items;
and a serial number, or other identifier, for the crane inspected.
•
The most recent certification record must be maintained on file until a new one
is prepared.
Tower Cranes
•
Adequate clearance must be maintained between moving and rotating
structures of the crane and fixed objects to allow the passage of employees
without harm.
•
Each employee required to perform duties on the horizontal boom of
hammerhead tower cranes must be protected against falling by guardrails or
by a personal fall arrest system that meets the requirements of the OSHA Fall
Protection Standard.
•
Buffers must be provided at both ends of travel of the trolley.
•
Cranes mounted on rail tracks must be equipped with limit switches limiting the
travel of the crane on the track and stops or buffers at each end of the tracks.
•
All tower cranes in use must meet the applicable requirements for design,
construction, installation, testing, maintenance, inspection, and operation as
prescribed by the manufacturer.
Overhead and Gantry Cranes
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The rated load of the crane must be plainly marked on each side of the crane.
If the crane has more than one hoisting unit, each hoist must have its rated
load marked on it or its load block, and this marking must be clearly legible
from the ground or floor.
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Bridge trucks must be equipped with sweeps which extend below the top of the
rail and project in front of the truck wheels.
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Except for floor-operated cranes, a gong or other effective audible warning
signal must be provided for each crane equipped with a power traveling
mechanism.
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All overhead and gantry cranes in use must meet the applicable requirements
for design, construction, installation, testing, maintenance, inspection, and
operation as prescribed by ANSI.
Derricks
Derricks also are used to move heavy loads. A derrick is a device consisting of a mast
held at the head by guys or braces. The equipment may or may not have a boom and
is used with a hoisting mechanism and operating ropes. Most derricks have a tall
framework over a drilled hole, especially when used on a barge as part of an oil well
There are A-frame derricks and basket derricks. An A-frame derrick has a boom
hinged from a cross member that is highly secured. On the other hand, a basket
derrick works without a boom with its base supported by attached ropes that raise
and lower the loads.
All derricks in use must meet the applicable requirements for design, construction,
installation, inspection, testing, maintenance, and operation as prescribed in
American National Standards Institute B30.6, Safety Code for Derricks.
Mobile Cranes Mounted on Barges
• When a mobile crane is mounted on a barge, the rated load of the crane must
not exceed the original capacity specified by the manufacturer.
• A load rating chart, with clearly legible letters and figures, must be provided
with each crane and securely fixed at a location easily visible to the operator.
• When load ratings are reduced to stay within the limits for list of the barge with
a crane mounted on it, a new load rating chart must be provided.
• Mobile cranes on barges must be positively secured.
Permanently Mounted Floating Cranes and Derricks
• When cranes and derricks are permanently installed on a barge, the capacity
and limitations of use must be based on competent design criteria.
• A load rating chart with clearly legible letters and figures must be provided and
securely fixed at a location easily visible to the operator.
• Floating cranes and floating derricks in use must meet the applicable
requirements for design, construction, installation, testing, maintenance, and
operation as prescribed by the manufacturer.
Protection of Employees Working on Barges
• The employer must comply with the applicable requirements for protection of
employees working onboard marine vessels as specified by OSHA.
Helicopter Cranes
Helicopter cranes provide a cost-effective alternative to more traditional construction
methods. Helicopter cranes can pour concrete and erect steel structures in areas
where ground-based cranes are not suitable. Such locations as soft or swampy
ground, steep mountain terrain, environmentally protected areas, and offshore
islands are easily accessed by helicopter cranes for delivery and placement of
construction materials and equipment.
Helicopter cranes must be inspected to comply with any applicable regulations of the
Federal Aviation Administration.
Helicopter Equipment
Operator Responsibility
The helicopter operator must be responsible for the size, weight, and manner in which
loads are connected to the helicopter. If, for any reason, the helicopter operator
believes the lift cannot be made safely, the lift must not be made.
Slings and Tag Lines
The load must be properly slung. Tag lines must be of a length that will not allow
them to be drawn up into rotors.
Pressed sleeves, swedged eyes, or equivalent means must be used for all freely
suspended loads to prevent hand splices from spinning open or cable clamps from
loosening.
Static Charge
Static charge on the suspended load must be dissipated with a grounding device
before ground personnel touch the suspended load, or protective rubber gloves must
be worn by all ground personnel touching the suspended load.
Weight Limitation
The weight of an external load must not exceed the manufacturer's rating.
Ground Lines
Hoist wires or other gear, except for pulling lines or conductors that are allowed to
"pay out" from a container or roll off a reel, must not be attached to any fixed ground
structure or allowed to foul on any fixed structure.
Operating Helicopters
Hooking and Unhooking Loads
When employees are required to perform work under hovering craft, a safe means of
access must be provided for employees to reach the hoist line hook and engage or
disengage cargo slings.
Employees must not perform work under hovering craft except when necessary to
hook or unhook loads.
Visibility
When visibility is reduced by dust or other conditions, ground personnel must
exercise special caution to keep clear of main and stabilizing rotors. Precautions also
must be taken by the employer to eliminate reduced visibility as far as practical.
Signal Systems
Signal systems between air crew and ground personnel must be understood and
checked in advance of hoisting the load. This applies to either radio or hand signal
systems.
Approach Distance
No unauthorized person must be allowed to approach within 50 feet of the helicopter
when the rotor blades are turning.
Approaching Helicopter
Whenever approaching or leaving a helicopter with blades rotating, all employees
must remain in full view of the pilot and keep in a crouched position. Employees must
avoid the area from the cockpit or cabin rearward unless authorized by the helicopter
operator to work there.
Working with Competent and Qualified Personnel
When using cranes and other lifting equipment always work with a manufacturer or
vender that has experience with your type of lift and jobsite situation. Working with
the appropriate competent and qualified professionals when lifting is as critical as the
lift itself.
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Competent person - means one who is capable of identifying existing and
predictable hazards in the surroundings or working conditions which are
unsanitary, hazardous, or dangerous to employees, and who has
authorization to take prompt corrective measures to eliminate them.
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Qualified person - means one who, by possession of a recognized degree,
certificate, or professional standing, or who by extensive knowledge,
training, and experience, has successfully demonstrated his ability to solve
or resolve problems relating to the subject matter, the work, or the project.
Helicopter General Safety
Briefing
A briefing must be conducted prior to each day's operation. This briefing must set
forth the plan of operation for the pilot and ground personnel.
Personal Protective Equipment
Personal protective equipment for employees receiving the load must consist of
complete eye protection and hard hats secured by chin straps.
Loose clothing likely to flap in the downwash, and thus be snagged on hoist line, must
not be worn.
Loose Gear and Objects
Every practical precaution must be taken to provide to protect employees from flying
objects in the rotor downwash. All loose gear within 100 feet of the place of lifting the
load, depositing the load, and all other areas susceptible to rotor downwash must be
secured or removed.
Housekeeping
Good housekeeping must be maintained in all helicopter loading and unloading areas.
Personnel
Sufficient ground personnel must be provided when required for safe helicopter
loading and unloading operations.
Communications
There must be constant reliable communication between the pilot and a designated
employee of the ground crew who acts as a signalman during the period of loading
and unloading. This signalman must be distinctly recognizable from other ground
personnel.
Fires
Open fires must not be permitted in an area where such fires could be spread by the
rotor downwash.
General Requirements
There are several general requirements for working with cranes. These safety
standards involve crane operations, equipment inspection, and fire and electrical
safety.
The employer must comply with the manufacturer's specifications and limitations
applicable to the operation of any and all cranes and derricks. Where manufacturer's
specifications are not available, the limitations assigned to the equipment must be
based on the determinations of a qualified engineer competent in this field and be
appropriately documented and recorded. Attachments used with cranes must not
exceed the capacity, rating, or scope recommended by the manufacturer.
Basic Operation
Rated load capacities, recommended operating speeds, and special hazard warnings
or instruction must be conspicuously posted on all equipment. Instructions or
warnings must be visible to operators while they are at their control stations.
Hand signals to crane and derrick operators must be those prescribed by the
applicable ANSI standard for the type of crane in use. An illustration of the signals
must be posted at the job site. The employer must designate a competent person
who must inspect all machinery and equipment prior to each use, and during use, to
make sure it is in safe operating condition. Any deficiencies must be repaired, or
defective parts replaced, before continued use.
Basic Inspection Requirements For Equipment
A thorough, annual inspection of the hoisting machinery must be made by a
competent person, or by a government or private agency recognized by the U.S.
Department of Labor. The employer must maintain a record of the dates and results
of inspections for each hoisting machine and piece of equipment.
Wire rope must be taken out of service when any of the following conditions exist:
• In running ropes, six randomly distributed broken wires in one lay or three
broken wires in one strand in one lay
• Wear of one-third the original diameter of outside individual wires
• Kinking, crushing, bird caging, or any other damage resulting in distortion of
the rope structure
• Evidence of any heat damage from any cause
• Reductions from nominal diameter of more than 1/64 inch for diameters up to
and including 5/16 inch, 1/32 inch for diameters 3/8 inch to and including 1/2
inch, 3/64 inch for diameters 9/16 inch to and including 3/4 inch, 1/16 inch for
diameters 7/8 inch to 1 inch inclusive, 3/32 inch for diameters 1 1/4 to 1 1/2
inches inclusive
• In standing ropes, more than two broken wires in one lay in sections beyond
end connections or more than one broken wire at an end connection
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Wire rope safety factors must be in accordance with American National
Standards Institute B30.5 or SAE J959.
Basic OSHA Requirements
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Belts, gears, shafts, pulleys, sprockets, spindles, drums, fly wheels, chains, or
other reciprocating, rotating, or other moving parts or equipment must be
guarded if such parts are exposed to contact by employees or otherwise create
a hazard.
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Accessible areas within the swing radius of the rear of the rotating
superstructure of the crane, either permanently or temporarily mounted, must
be barricaded to prevent an employee from being struck or crushed by the
crane.
All exhaust pipes must be guarded or insulated in areas where contact by
employees is possible in the performance of normal duties.
Whenever equipment powered by an internal combustion engine exhausts in
enclosed spaces, tests must be made and recorded to see that employees are
not exposed to unsafe concentrations of toxic gases or oxygen-deficient
atmospheres.
All windows in cabs must be made of safety glass or equivalent material that
does not visibly distort the view and interfere with the safe operation of the
machine.
Where necessary for rigging or service requirements, a ladder or steps must be
provided to give access to a cab roof. Guardrails, handholds, and steps must be
provided on cranes for easy access to the car and cab, conforming to American
National Standards Institute B30.5.
Platforms and walkways must have anti-skid surfaces.
No modifications or additions that affect the capacity or safe operation of the
equipment must be made by the employer without the manufacturer's written
approval. If such modifications or changes are made, the capacity, operation,
and maintenance instruction plates, tags, or decals, must be changed
accordingly. In no case must the original safety factor of the equipment be
reduced.
All employees must be kept clear of loads about to be lifted and of suspended
loads.
Basic Fire Protection on Cranes
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Fuel tank filler pipe must be located in such a position or protected in such a
manner that will not allow a spill or overflow to run onto the engine, exhaust,
or electrical equipment of any machine being fueled.
An accessible fire extinguisher of 5BC rating or higher must be available at all
operator stations or in cabs of equipment.
All fuels must be transported, stored, and handled to meet the OSHA
requirements. When fuel is transported by vehicles on public highways,
Department of Transportation rules contained in 49 CFR Parts 177 and 393
concerning such vehicular transportation are considered applicable.
Basic Electrical Safety on Cranes
Except where electrical distribution and transmission lines have been de-energized
and visibly grounded at point of work or where insulating barriers have been erected
to prevent physical contact with the lines, equipment or machines near power lines
must be operated only in accordance with the following:
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For lines rated 50kV or below, minimum clearance between the lines and any
part of the crane or load must be 10 feet.
For lines rated over 50kV, minimum clearance between the lines and any part
of the crane or load must be 10 feet plus 0.4 inch for each 1kV over 50kV or
twice the length of the line insulator, but never less than 10 feet.
In transit with no load and boom lowered, the equipment clearance must be a
minimum of 4 feet for voltages less than 50kV and 10 feet for voltages over
50kV, up to and including 345kV, and 16 feet for voltages up to and including
750kV.
A person must be designated to observe clearance of the equipment and give
timely warning for all operations where it is difficult for the operator to
maintain the desired clearance by visual means.
Cage-type boom guards, insulating links, or proximity warning devices may be
used on cranes, but the use of such devices must not alter the requirements of
any other regulation of this part even if such device is required by law or
regulation.
Any overhead wire must be considered to be an energized line unless and until
the person owning such line or the electric utility authorities indicate that it is
not an energized line and it has been visibly grounded.
Prior to work near transmitter towers where an electrical charge can be induced in the
equipment or materials being handled, the transmitter must be de-energized or tests
must be made to determine if electrical charge is induced on the crane. All of the
following precautions must be taken when necessary to dissipate induced voltages:
• The equipment must be provided with an electrical ground directly to the upper
rotating structure supporting the boom.
• Ground jumper cables must be attached to materials being handled by boom
equipment when an electrical charge is induced while working near energized
transmitters. Crews must be provided with nonconductive poles having large
alligator clips or other similar protection to attach the ground cable to the load.
• Combustible and flammable materials must be removed from the immediate
area prior to operations.
Topic Summary
Please take a moment to review these key points before you continue with the next
topic.
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There are six types of cranes: boom trucks, truck, crawlers, rough terrain,
mobile tower, and heavy lifting. Each has unique OSHA requirements.
The six types of cranes are categorized as mobile, fixed, or overhead. Each
category has its own set of safety specifications.
Derricks are lifting devices with or without booms used with a hoisting
mechanism and operating ropes.
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General requirements for helicopter crane safety are categorized as general,
operating, or equipment.
Topic 3: Crane Principles and Operations
Overview
This topic will review the basic lifting principles and operational practices for lifting or
moving heavy loads. Upon completing this topic, you will be able to:
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Identify the three main reasons why working with cranes can be hazardous
Discuss the four basic lifting principles that govern a crane's mobility and
safety during operation
Identify crane capabilities, limitations, and job site restrictions for safe
operations
Describe special operational considerations for cranes powered by internal
combustion engines or electric motors
Crane Failures
Cranes may fail because of poor structure, stability, rigging, and other reasons.
Please note these areas of crane use likely to be dangerous.
1. Structural
• Outrigger failure
• Two-blocking
• Boom buckling
2. Stability
• Side pull
• Upset/overturn
• Oversteer/crabbing
3. Rigging
• Killer hooks (without a throat latch) rigging
4. Combination Stability/Structure
• Overloading
• Unintentional turntable turning
5. Electrical
• Power-line contact
Lifting Principles
There are four basic lifting principles that govern a crane's mobility and safety during
lifting operations.
1. Center of Gravity
The center of gravity of any object is the point in the object where its weight
can be assumed to be concentrated; stated another way, it is the point in the
object around which its weight is evenly distributed. The location of the center
of gravity of a mobile crane depends primarily on the weight and location of its
heaviest components (boom, carrier, upperworks, and counterweight).
2. Leverage
Cranes use the principle of leverage to lift loads. Rotation of the upperworks
(cab, boom, counterweight, load) changes the location of the crane's center of
gravity, its leverage point or fulcrum.
As the upperworks rotates, the leverage of a mobile crane fluctuates. This
rotation causes the crane's center of gravity to change and causes the distance
between the crane's center of gravity and its tipping axis also to change.
Stability can be affected by the fluctuating leverage the crane exerts on the
load as it swings. Therefore, the crane's rated capacity is altered in the load
chart to compensate for those changes in leverage.
Provided the ground is capable of supporting the load, a crane can be
mademore stable by moving the tipping axis farther away from its center of
gravity.
The extra stability gained by moving the tipping axis can then be used to carry
larger/heavier loads.
3. Stability
Stability is the relationship of the load weight, angle of the boom, and its radius
(distance from the crane's center of rotation to the center of the load) to the
center of gravity of the load. The stability of a crane could also be affected by
the support on which the crane is resting. A crane's load rating generally is
developed for operation under ideal conditions, i.e., a level, firm surface.
Therefore, unlevel surfaces or soft ground must be avoided. In areas where
soft ground poses a support problem for stability, mats and/or blocking should
be used to distribute a crane's load and maintain a level, stable condition.
In addition to overturning (stability failure), cranes can fail structurally if
overloaded enough. Structural failure may occur before there is any sign of
tipping. In other words, a mobile crane's structure may fail long before it tips.
Structural failure is not limited to total fracture; it includes all permanent
damage such as overstressing, bending, and twisting of any of the
components. When a crane is overstressed, the damage may not be apparent.
Nevertheless, a structural failure has occurred, and overstressed components
are then subject to catastrophic failure at some future time.
4. Structural Integrity
The crane's mainframe, crawler track, and/or outrigger supports, boom
sections, and attachments are all considered part of the structural integrity of
lifting. In addition, all wire ropes, including stationary supports or attachment
points, help determine lifting capacity and are part of the overall structural
integrity of a crane's lifting capacity. The following elements also may affect
structural integrity:
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The load chart capacity in relationship to stability
The boom angle limitations which affect stability and capacity
The knowledge of the length of boom and radius in determining capacity
Stability failures are foreseeable, but in structural failure it is almost impossible
to predict which component will fail at any given time. No matter what the
cause, if the crane is overloaded, structural failure can occur.
Operating Considerations
Cranes are carefully designed, tested, and manufactured for safe operation. When
used properly they can provide safe, reliable service to lift or move loads. Crane
operators and personnel working with cranes need to be knowledgeable about basic
crane capacities, limitations, and specific job site restrictions, such as location of
overhead electric power lines, unstable soil, or high winds.
Crane and Derrick Operations
The OSHA rule prohibits hoisting personnel by crane or derrick except when no
safe alternative is possible.
OSHA stresses that employee safety - not practicality or convenience - must be
the basis for the employer's choice of method.
Cranes and derricks used to hoist personnel must be placed on a firm
foundation, and the crane operator must always be at the controls when the
crane engine is running and the personnel platform occupied.
Wire rope used for personnel lifting must have a minimum safety factor of
seven. (This means it must be capable of supporting seven times the maximum
intended load.) Rotation-resistant rope must have a minimum safety factor of
10.
When the occupied personnel platform is in a stationary position, all brakes and
locking devices on the crane or derrick must be set.
Instruments and Components
Cranes and derricks with variable angle booms must have a boom angle
indicator that is visible to the operator.
Cranes with telescoping booms must be equipped with a device to clearly
indicate the boom's extended length, or an accurate determination of the load
radius to be used during the lift must be made prior to hoisting personnel.
Cranes and derricks also must be equipped with (1) an anti-two-blocking
device that prevents contact between the load block and overhaul ball and the
boom tip or (2) a two-block damage-prevention feature that deactivates the
hoisting action before damage occurs.
Personnel Platforms
Platforms used for lifting personnel must be designed by a qualified person with
a minimum safety factor of five. The suspension system must be designed to
minimize tipping due to personnel movement on the platform.
Each personnel platform must be provided with a standard guardrail system
that is enclosed from the toe board to the midrail to keep tools, materials, and
equipment from falling on employees below. The platform also must have an
inside grab rail, adequate headroom for employees, and a plate or other
permanent marking that clearly indicates the platform's weight and rated load
capacity or maximum intended load.
Loading
The personnel platform must not be loaded in excess of its rated load capacity
or its minimum intended load.
Only personnel instructed in the requirements of the standard and the task to
be performed - along with their tools, equipment, and materials needed for the
job - are allowed on the platform. Materials and tools must be secured and
evenly distributed to balance the load while the platform is in motion.
Rigging
When a wire rope bridle is used to connect the platform to the load line, the
bridle legs must be connected to a master link or shackle so the load is evenly
positioned among the bridle legs. Bridles and associated rigging for attaching
the personnel platform to the hoist line must not be used for any other
purpose.
Attachment assemblies such as hooks must be closed and locked to eliminate
the hook throat opening; an alloy anchor-type shackle with a bolt, nut, and
retaining pin may be used as an alternative. "Mousing" (wrapping wire around
a hook to cover the hook opening) is not permitted.
Prelift Meeting
The employer must hold a meeting with all employees involved in personnel
hoisting operations (crane or derrick operator, signal person(s), employees to
be lifted, and the person responsible for the hoisting operation) to review the
OSHA requirements and the procedures to be followed before any lift
operations are performed.
This meeting must be held before the trial lift at each new work site and must
be repeated for any employees newly assigned to the operation.
Inspecting And Testing
A trial lift of the unoccupied personnel platform must be made before any
employees can be hoisted. The trial lift must be performed immediately prior to
placing personnel on the platform. If a crane or derrick is moved to a new
location or returned to a previously used one, the trial lift must be repeated
before hoisting personnel.
The crane or derrick operator must check all systems, controls, and safety
devices to ensure the following:
• They are functioning properly.
• There are no interferences.
After the trial lift, the personnel platform must be hoisted a few inches and
inspected to ensure that it remains secured and is properly balanced. Before
employees are hoisted, a check must be made to ensure the following:
• Hoist ropes are free of kinks.
• Multiple part lines are not twisted around each other.
• The primary attachment is centered over the platform.
• There is no slack in the wire rope.
• All ropes are properly seated on drums and in sheaves.
Any defects found during inspections must be corrected before hoisting
personnel. The platform and rigging must be proof-tested to 125 percent of the
platform's rated capacity, and then a competent person must inspect the
platform and rigging for defects. If any problems are detected, they must be
corrected and another proof test must be conducted. Personnel hoisting must
not be conducted until the proof-testing requirements are satisfied.
Safe Work Practices
Employees, too, can contribute to safe personnel hoisting operations and help
reduce the number of accidents and injuries associated with personnel hoisting
operations.
Employees must follow these safe work practices:
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Use tag lines unless their use creates an unsafe condition.
Keep all body parts inside the platform during raising, lowering, and
positioning.
Make sure a platform is secured to the structure where work is to be
performed before entering or exiting it, unless such securing would
create an unsafe condition.
Wear a body belt or body harness system with a lanyard.
The lanyard must be attached to the lower load block or overhaul ball or
to a structural member within the personnel platform. If the hoisting
operation is performed over water, OSHA requirements must apply.
Stay in view of, or in direct communication with, the operator or signal
person.
Crane and derrick operators must follow these safe work practices:
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Never leave crane or derrick controls when the engine is running or
when the platform is occupied.
Stop all hoisting operations if there are indications of any dangerous
weather conditions or other impending danger.
Do not make any lifts on another load line of a crane or derrick that is
being used to hoist personnel.
Movement of Cranes
Personnel hoisting is prohibited while the crane is traveling except when the
employer demonstrates that this is the least hazardous way to accomplish the
task or when portal, tower, or locomotive cranes are used.
When
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cranes are moving while hoisting personnel, the following rules apply:
Travel must be restricted to a fixed track or runway.
Travel also must be limited to the radius of the boom during the lift.
The boom must be parallel to the direction of travel.
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There must be a complete trial run before employees occupy the
platform.
If the crane has rubber tires, the condition and air pressure of the tires
must be checked and the chart capacity for lifts applied to remain under
the 50-percent limit of the hoist's rated capacity. Outriggers may be
partially retracted as necessary for travel.
Compliance with the common-sense requirements of the OSHA standard and
the determination that no other safe method is available should greatly reduce
or eliminate the injuries and accidents that occur too frequently during
personnel hoisting operations.
Load Chart Considerations
Factors to be considered when calculating a crane's load capacity include the
following:
• Load Radius: the horizontal distance between the center of the crane
rotation to center of the load
• Boom length: including the jib, swing away extension, or any other
attachments that may increase length of the boom
• Parts of line:
• Quadrant of operation: the area of operation in which the lift is being
made (Note that different quadrants usually have lower lifting
capacities.)
• Boom angle: the angle formed between the horizontal plane of rotation
and centerline of the boom
• Weight of any attachments: jib, lattice extension, or auxiliary boom point
• Weight of handling devices: ball, block, and/or any necessary rigging
Critical Lifts
Any pick that meets any of the following criteria is considered a critical lift and
requires additional safety measures prior to commencing the lift.
• Tandem picks
• Net weight of load exceeding 25 tons
• Value of load exceeding $50,000
• Replacement time for damaged load exceeding two months
• Gross load weight exceeding 85 percent of crane's rated capacity
Special Operating Considerations
This section applies to crawler cranes, locomotive cranes, wheel-mounted cranes of
both truck and self-propelled wheel type, and any other moving crane types. These
are cranes powered by internal combustion engines or electric motors that use drums
and ropes. Cranes designed for railway and automobile wreck clearances are
excepted. These requirements apply only to machines when used as lifting cranes.
Nine standard hand signals provide safety for working around moving cranes.
1. Hoist: With forearm vertical, forefinger pointing up, move hand in small circles
2. Lower: With arm extended downward, forefinger pointing down, move the hand in
small horizontal circles.
3. Bridge Travel: Arm extended forward, hand open and slightly raised, make a
pushing motion in the direction of travel.
4. Trolley Travel: Palm up, fingers closed, thumb pointing in direction of motion, jerk
the hand horizontally.
5. Stop: Arm extended, palm down, move the arm back and forth horizontally.
6. Emergency Stop: Both arms extended, palms down, move arms back and forth
horizontally.
7. Multiple Trolleys: Hold up one finger for the block marked "1" and two fingers for
the block marked "2." Regular signals follow.
8. Move Slowly: Use one hand to give any motion signal and place other hand
motionless in front of the hand giving the motion signal.
9. Magnet Is Disconnected: Crane operator spreads both hands apart with the palms
up.
CASE STUDY
A 33-year-old well driller was electrocuted when a metal pipe lifted by a truckmounted crane contacted a 12,000-volt overhead power line. The victim and a
coworker were repairing a submersible pump for a water well at a private residence.
The well was located in a pasture with three parallel power lines overhead. One of the
power lines passed directly over the well (32 feet above the ground). On the day of
the incident, the victim positioned the truck-mounted crane beneath the power line.
Using a handheld remote-control pendant, the victim fully extended the end of the
boom 36 feet above the ground. The crane cable was attached to a one-inch-diameter
galvanized pipe that ran to the pump inside the well. As the victim raised the pipe, it
contacted the power line directly above the well, energizing the crane and the
handheld remote-control pendant. The victim provided a path to ground and was
electrocuted.
CASE STUDY
A 37-year-old construction laborer was electrocuted while pulling a wire rope attached
to a crane cable toward a load. The choker was to be connected to a steel roof joist
that was to be lifted 150 feet across the roof of a one-story school and set in place.
The cab of the crane was positioned 11 feet 6 inches from a 7200-volt power line.
After a previous roof joist had been set in place, the crane operator swung the crane
boom and cable back toward the victim, who grabbed the choker in his left hand.
With his right hand, he held onto a steel rod that had been driven into the ground
nearby. At this point, the momentum of the swinging crane apparently caused the
crane cable to contact the power line. The electrical current passed across the victim's
chest and through the steel rod to ground, causing his electrocution.
Topic Summary
Please take a moment to review these key points before you continue with the next
topic.
• Cranes are at risk because of their structure, stability, and rigging.
• The four basic lifting principles are the center of gravity, leverage, stability, and
structural integrity.
• There are nine standard hand signals that provide directional safety for working
around moving cranes.
• Crane operational considerations were outlined in these areas:
o Crane and derrick operations
o Instruments and components
o Personnel platforms
o Loading
o Rigging
o Inspecting and testing
o Prelifting meeting
o Safe work practices
o Movement of cranes
o Load chart considerations
o Critical lifts
o Working with competent and qualified personnel
Topic 4: Associated Lifting Equipment
This topic covers the specifications and limitations applicable to working with hoists
and elevators. Upon completing this lesson, you will be able to:
• Identify the risks and standards for working with different types of hoists
• Identify requirements for the use of conveyors
General Requirements
The employer must comply with the manufacturer's specifications and limitations
applicable to the operation of all hoists and elevators. Where manufacturer's
specifications are not available, the limitations assigned to the equipment must be
based on the determinations of a professional engineer competent in the field.
The specifications relate to the use of ropes, booms, and belt-type manlifts. Please
examine the following general requirements for hoists.
Rated load capacities, recommended operating speeds, and special hazard warnings
or instructions must be posted on cars and platforms.
Wire rope must be removed from service when any of the following conditions exist:
• In hoisting ropes, six randomly distributed broken wires in one rope lay or
three broken wires in one strand in one rope lay
• Abrasion, scrubbing, flattening, or peeling, causing loss of more than one-third
of the original diameter of the outside
• Evidence of any heat damage resulting from a torch or any damage caused by
contact with electrical wires
• Reduction from nominal diameter of more than 3/64 inch for diameters up to
and including 3/4 inch, 1/16 inch for diameters 7/8 to 1 inch, and 3/32 inch for
diameters 1 1/4 to 1 1/2 inches
Hoisting ropes must be installed in accordance with the wire rope manufacturers'
recommendations.
The installation of live booms on hoists is prohibited.
The use of endless belt-type manlifts on construction is prohibited.
Material Hoists
All material hoists must conform to the requirements of ANSI A10.5, Safety
Requirements for Material Hoists. Click each specification to learn more about it.
Operating
Operating rules must be established and posted at the operator's station of the hoist.
Such rules must include signal system and allowable line speed for various loads.
Rules and notices must be posted on the car frame or crosshead in a conspicuous
location, including the statement "No Riders Allowed." In addition, no person must be
allowed to ride on material hoists except for the purposes of inspection and
maintenance.
Hoistways
Protect entrances with gates or bars (not less than 2- by 4-inch wooden bars or the
equivalent) with latching devices that guard the full width of the landing entrance.
Position the bars 2 feet from the hoistway line not less than 36 inches nor more than
42 inches above the floor. The bars and gates should be painted with diagonal
contrasting colors, such as black and yellow strips.
Overhead Protection
Overhead protective covering of 2-inch planking, 3/4-inch plywood, or other solid
material of equivalent strength must be provided on the top of every material hoist
cage or platform.
The operator's station of a hoisting machine must be provided with overhead
protection equivalent to tight planking not less than two inches thick. The support for
the overhead protection must be of equal strength.
Hoist Towers
A licensed professional engineer must design the hoist tower. Hoist towers may be
used with or without an enclosure on all sides. However, whichever alternative is
chosen, the following applicable conditions must be met:
Enclosed
It must be enclosed on all sides for its entire height with a screen enclosure of
1/2-inch mesh of No. 18 U.S. gauge wire or equivalent, except for landing
access.
Not Enclosed
The hoist platform or car must be totally enclosed (caged) on all sides for the
full height between the floor and the overhead protective covering with 1/2inch mesh of No. 14 U.S. gauge wire or equivalent. The hoist platform
enclosure must include the required gates for loading and unloading. A six-foot
high enclosure must be provided on the unused sides of the hoist tower at
ground level. Car-arresting devices must be installed to function in case of rope
failure.
Personnel Hoists
All personnel hoists used by employees must be constructed of materials and
components that meet the specifications for materials, construction, safety devices,
assembly, and structural integrity as stated in the American National Standard
Institute A10.4, Safety Requirements for Workmen's Hoists. The requirements of this
lesson do not apply to cantilever-type personnel hoists.
Towers
Outside Structure
Hoist towers outside the structure must be enclosed for the full height on the
side or sides used for entrance and exit to the structure. At the lowest landing,
the enclosure on the sides not used for exit or entrance to the structure must
be enclosed to a height of at least 10 feet. Other sides of the tower adjacent to
floors or scaffold platforms must be enclosed to a height of 10 feet above the
level of such floors or scaffolds.
Inside Structure
Towers inside structures must be enclosed on all four sides throughout the full
height.
Towers must be anchored to the structure at intervals not exceeding 25 feet. In
addition to tie-ins, a series of guys must be installed. Where tie-ins are not practical,
the tower must be anchored by means of guys made of wire rope at least 1/2 inch in
diameter, securely fastened to anchorage to ensure stability.
Hoistway
Hoistway doors or gates must be not less than six feet six inches high and must be
provided with mechanical locks that cannot be operated from the landing side,
accessible only to persons on the car.
Cars must be permanently enclosed on all sides and the top, except sides used for
entrance and exit that have car gates or doors. A door or gate must be provided at
each entrance to the car, which must protect the full width and height of the car
entrance opening. Doors or gates must be provided with electric contacts that do not
allow movement of the hoist when door or gate is open.
Overhead protective covering of 2-inch planking, 3/4-inch plywood, or other solid
material of equivalent strength must be provided on the top of every personnel hoist.
Safeties must be capable of stopping and holding the car and rated load when
traveling at governor-tripping speed.
Cars must be provided with a capacity and data plate secured in a conspicuous place
on the car or crosshead. Internal combustion engines must not be permitted for direct
drive. Normal and final terminal stopping devices must be provided. An emergency
stop switch must be provided in the car and be marked "Stop."
The minimum number of hoisting ropes used must be three for traction hoists and
two for drum-type hoists. The minimum diameter of hoisting and counterweight wire
ropes must be 1/2 inch. OSHA provides minimum safety factors for suspension wire
ropes.
Inspection
Following assembly and erection of hoists, and before being put into service, an
inspection and test of all functions and safety devices must be made under the
supervision of a competent person. A similar inspection and test is required following
major alteration of an existing installation.
All hoists must be inspected and tested at not more than three-month intervals. The
employer must prepare a certification record that includes the date the inspection and
test of all functions and safety devices was performed; the signature of the person
who performed the inspection and test; and a serial number, or other identifier, for
the hoist that was inspected and tested. The most recent certification record must be
maintained on file.
Other Equipment
These other hoisting methods must meet applicable requirements for their design.
Click each image to learn more about its particular safety precautions.
Base-Mounted Drum Hoists
Exposed moving parts such as gears, projecting screws, setscrews, chain, cables,
chain sprockets, and reciprocating or rotating parts must be guarded to avoid
hazards. Plus, all controls used during the normal operation cycle must be located
within easy reach of the operator's station.
Electric motor-operated hoists must be provided with:
• A device to disconnect all motors from the line upon power failure and not
permit any motor to be restarted until the controller handle is brought to the
"off" position
• Where applicable, an overspeed preventive device
• A means whereby remotely operated hoists stop when any control is ineffective
All base-mounted drum hoists in use must meet the applicable requirements for
design, construction, installation, testing, inspection, maintenance, and operations, as
prescribed by the manufacturer.
Overhead Hoists
For an overhead hoist to work safely, care should be given to its structure and
support and its installation only in locations that will permit the operator to stand
clear of the load at all times.
The supporting structure of the hoist must have a safe working load equal to that of
the hoist. The support must be arranged to provide for free movement of the hoist
and must not restrict the hoist from lining itself up with the load. The safe working
load of the overhead hoist, as determined by the manufacturer, must be indicated on
the hoist.
Air hoists must be connected to an air supply of sufficient capacity and pressure to
safely operate the hoist. All air hoses supplying air must be positively connected to
prevent their becoming disconnected during use.
All overhead hoists in use must meet the applicable requirements for construction,
design, installation, testing, inspection, maintenance, and operation, as prescribed by
the manufacturer.
Conveyors
Conveyors are a common device used with cranes for transporting and carrying
materials. This list provides several safety requirements for working with conveyors:
• A means for stopping the motor or engine must be provided at the operator's
station. Conveyor systems must be equipped with an audible warning signal to
be sounded immediately before starting up the conveyor.
• If the operator's station is at a remote point, similar provisions for stopping the
motor or engine must be provided at the motor or engine location.
• Emergency stop switches must be arranged so the conveyor cannot be started
again until the actuating stop switch has been reset to the running or "on"
position.
• Screw conveyors must be guarded to prevent employee contact with turning
flights.
• Where a conveyor passes over work areas, aisles, or thoroughfares, suitable
guards must be provided to protect employees required to work below the
conveyors.
• All crossovers, aisles, and passageways must be conspicuously marked by
suitable signs, as required by OSHA.
• Conveyors must be locked out or otherwise rendered inoperable and tagged
out with a "Do Not Operate" tag during repairs and when operation is
hazardous to employees performing maintenance work.
• All conveyors in use must meet the applicable requirements for design,
construction, inspection, testing, maintenance, and operation, as prescribed in
ANSI B20.1.
Topic Summary
Please take a moment to review these key points before you continue with the next
topic.
• General requirements for the use of hoists, elevators, and conveyors involve
ropes, booms, and belt-type manlifts.
• Operating specifications for material hoists include requirements for hoistways,
hoist towers, and overhead protection.
• Operating specifications for personnel hoists include towers, hoistways, cars,
and inspection.
Lesson Summary
This lesson contains information and instruction about cranes. By completing this
lesson, you should have the knowledge to discuss the following topics. Take a
moment to see if you can do the following:
• Identify general information and requirements for working with cranes
• Identify the different types of cranes and derricks and the related safe work
practices.
• Explain the four principles of crane lifting and describe crane operating
standards
• Determine the safety precautions for using all associated lifting equipment
Motor Vehicles
Introduction
Recently, the Pennsylvania Department of Transportation began a campaign
called "My Mommy Works Here" to try to slow traffic in road construction
areas. This campaign addresses the more than 2,000 deaths from occupational
motor vehicle incidents. These deaths annually account for more than 30
percent of all fatalities from occupational injuries and include:
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Driver and passenger deaths in highway crashes
Farm equipment incidents
Industrial vehicle incidents
Pedestrian fatalities
The National Safety Council (NSC) estimates 200,000 disabling injuries and
more than $4 billion in economic costs result from workplace motor vehicle
incidents.
The underlying causes of these fatalities and injuries vary widely, from
mechanical failure, to poor highway and vehicle design, to driver error.
Lesson Overview
This lesson presents information on the types of vehicles used in and around
construction job sites, the hazards associated with their use, and control
methods to reduce and/or eliminate these hazards.
Upon completing this lesson, you will be able to:
• Describe general safety requirements for all motor vehicle construction
equipment
• Explain the role of the Manual on Uniform Traffic Control Devices in
occupational safety
• List the dos and don'ts for safe entry and exit of a loader
• Describe areas of testing and licensing required for commercial motor
vehicle drivers
Why Learn This Lesson?
Anyone on a construction site can list many potential hazards in this work.
This lesson explores the additional hazards incurred by the presence of large
motor vehicles in and around the area.
The size of construction vehicles makes them a formidable force. Public
vehicles driving the roads that border or pass through these sites bring into
the picture drivers who are untrained to watch for the mix of men and
machines doing their jobs.
This lesson discusses the types of vehicles used in and around construction job
sites, the hazards associated with their use, and the control methods
established to reduce and/or eliminate death and injury to workers.
The learner will have an opportunity to view several types of equipment
common to all construction sites, powered industrial truck standards, and
rollover protection standards (ROPS). A description of the importance of the
Manual on Uniform Traffic Controls Devices (MUTCD), its purpose, and its
importance will also be given.
Topic 1: OSHA's General Provisions
The Occupational Safety and Health Administration (OSHA) has established
numerous requirements for safe use of equipment and motor vehicles on a
construction site. This topic reviews OSHA's general requirements for all motor
vehicle construction equipment.
Upon completing this topic, you will be able to:
• Describe general requirements for all construction equipment
• List six items on a construction vehicle intended for non-road use that
are regulated by OSHA
• Specify some of the parts common to construction vehicles that should
be checked prior to each shift
• Specify examples of materials-handling equipment
General Requirements for All Equipment
No specific OSHA standards concern workplace motor vehicle safety; however,
most occupational fatalities occur on public highways where there are seat belt
requirements and traffic laws. OSHA and NIOSH are currently working with the
National Highway Traffic Safety Administration (NHTSA) to extract better data
from existing databases on the underlying causes of vehicle-related
occupational injuries.
Each piece of equipment used on the worksite can have specific requirements
for maintaining safe operation and special precautions to avoid injury, but
there are general statements that apply to all motor vehicles used in the
construction industry.
General Requirements
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Equipment left unattended at night must have appropriate lights or
reflectors, or barricades with appropriate lights or reflectors must be
erected to identify the location of the equipment.
Parked equipment must have the parking brake set. When equipment is
parked on inclines, the wheels must be chocked.
A safety tire rack or cage must be provided and used when inflating,
mounting, or dismounting tires installed on split rims or rims equipped
with locking rings or similar devices.
Equipment must be substantially blocked or cribbed to prevent falling or
shifting before employees are permitted to work under or between any
heavy machinery or equipment suspended or held aloft by slings, hoists,
or jacks.
When bulldozer and scraper blades, end-loader buckets, dump bodies,
and similar equipment are being repaired or are not in use, they must be
fully lowered or blocked. Additionally, all controls must be in a neutral
position, with motors stopped and brakes set, unless the work being
performed requires otherwise.
Safety glass with no visible distortion that would affect the safe
operation of the machine must be used for all cab glass.
Motor Vehicles
Motor vehicle requirements apply to vehicles that operate within an offhighway job site that is not open to public traffic. These requirements do not
apply to equipment used for material handling, which will be covered in the
next topic.
Vehicles must be equipped with:
1. An operable service brake system, emergency brake system, and
parking brake system
2. At least two headlights, two taillights, and brake lights
3. A working audible warning device
4. Powered wipers and windshields that are not cracked
5. Seat belts
6. Defogging or defrosting devices when operating in areas or under
conditions that cause windshield fogging or frosting
Shift Requirements
At the beginning of each shift, all vehicles in use must be checked to assure
that the following parts, equipment, and accessories are in safe operating
condition and free of apparent damage that could cause failure while in use:
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Service brakes, including trailer brake connections
Parking system (hand brake)
Emergency stopping system (brakes)
Tires
Horn
Steering mechanism
Coupling devices
Seat belts
Operating controls
Safety devices
Special purpose vehicles have other requirements:
All haulage vehicles, whose payload is loaded by cranes, power shovels,
loaders, or similar equipment, must have a cab shield and/or a canopy that is
adequate to protect the operator. Operating levers that control the hoisting or
dumping devices on haulage bodies must be equipped with a latch or other
device to prevent accidental starting or tripping of the mechanism.
Employee transport vehicles must have enough firmly secured seats for the
number of employees to be carried. Tools and materials must be secured to
prevent movement when being transported in the same compartment with
employees.
Trucks with dump bodies must be equipped with a positive, permanently
attached means of support. This support should be locked in position to
prevent the accidental lowering of the body while performing any maintenance
or inspection work. Trip handles for dump truck tailgates must be located so
that the operator is in the clear during dumping.
Motor vehicle equipment should not be used when there is an obstructed rear
view unless either:
• The vehicle has a reverse signal alarm audible above the surrounding
noise level
• The vehicle is backed up only when an observer signals that it is safe to
do so
Earthmoving Equipment
Earthmoving equipment includes vehicles such as:
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Scrapers
Loaders
Crawlers or wheel tractors
Bulldozers
Off-highway trucks
Graders
Agricultural and industrial tractors
Similar equipment
The specifications for this equipment state that:
1. Every emergency access ramp and berm that is used must be
constructed to restrain and control runaway vehicles.
2. All earthmoving equipment must have a service braking system that is
capable of stopping and holding fully loaded equipment.
3. All bi-directional machines, such as rollers, compacters, front-end
loaders, bulldozers, and similar equipment must be equipped with a horn
in good working order that is distinguishable from the surrounding noise
level.
4. Earthmoving or compacting equipment that has an obstructed rear view
cannot be used in reverse gear unless it has a reverse signal alarm in
operation that is distinguishable from the surrounding noise level or if an
employee signals that it is safe to back up.--Dup
5. Scissor points on all front-end loaders must be guarded, because they
constitute a hazard to the operator during normal operation.
6. Seat belts must be provided on all equipment listed in this topic.
Exceptions: Seat belts are not required on equipment designed only for
standup operation and equipment that does not have a rollover protective
structure (ROPS) or adequate canopy protection.
Construction equipment or vehicles cannot be moved onto any access roadway
or grade unless it is constructed and maintained to safely accommodate the
movement of the equipment and vehicles involved.
Powered Industrial Trucks
Powered industrial trucks must meet the following general requirements:
• Lift trucks, stackers, etc., must have the rated capacity clearly posted on
the vehicle, and these ratings must not be exceeded.
• Modifications or additions affecting the capacity or safe operation of the
equipment cannot be made without the manufacturer's written approval.
• If two or more trucks lift a load by working in unison, the proportion of
the total load carried by any one truck must not exceed its capacity.
• Steering or spinner knobs must not be attached to the steering wheel.
An exception would be in a case where the steering mechanism prevents
road reactions from causing the steering handwheel to spin. When used,
the steering knob must be mounted within the periphery of the wheel.
• Unauthorized personnel must not be permitted to ride on powered
industrial trucks. Where riding of trucks is authorized, a safe place to
ride must be provided.
Pile Driving Equipment
Piles consist of natural materials or pre-manufactured structural shapes built
to precise tolerances utilizing high-strength materials and reliable quality
control. Piles are selected to meet the specific needs of the structure and site
conditions and can be steel, concrete, or timber.
Driven piles are usually installed in a manner that produces no spoils for
removal and therefore no exposure to or disposal problems with potentially
hazardous or contaminated materials.
Equipment Guidelines:
• Overhead protection, equivalent to two-inch planking or other solid
material of equivalent strength, which will not obscure the vision of the
operator while pile driving equipment is in operation
• Stop blocks for the leads to prevent the hammer from being raised
against the head block
• A blocking device capable of safely supporting the weight of the hammer
(This device is placed in the leads under the hammer at all times while
employees are working under the hammer.)
• Guards across the top of the head block to prevent the cable from
jumping out of the sheaves
• Stabilizing the leads when they must be inclined in the driving of batter
piles
• Attaching a steam hose leading to a steam hammer or jet pipe securely
to the hammer with an adequate length of at least 1/4-inch diameter
chain or cable (This will prevent whipping if the joint at the hammer is
broken. Air hammer hoses must be provided with this same protection.)
• Steam line controls consisting of two shutoff valves, one of which must
be a quick-acting lever type within easy reach of the hammer operator
• Requiring guys, outriggers, thrustouts, or counterbalances as necessary
to maintain stability of pile driver rigs
• Suspending pile-driving operations when it is necessary to cut off the
tops of driven piles (An exception exists where cutting operations are
located at least twice the length of the longest pile from the driver.)
Employee Guidelines:
• Maintaining employees well beyond the range of falling materials when
steel tube piles are being "blown out"
• Having engineers and winchmen accept signals only from the designated
signalmen
• Keeping all employees clear when piling is being hoisted into the leads
Site Clearing
Employees engaged in site clearing must be protected from irritant and toxic
plant hazards and suitably instructed in the first aid treatment available.
All equipment used in site-clearing operations must be equipped with rollover
guards. In addition, rider-operated equipment must be equipped with an
overhead and rear canopy guard meeting the following requirements:
• The overhead covering on the canopy structure must be of not less than
1/8-inch steel plate or 1/4-inch woven wire mesh with no openings
greater than 1 inch, or equivalent.
• The opening in the rear of the canopy structure must be covered with
not less than 1/4-inch woven wire mesh with openings no greater than 1
inch.
Topic Summary
Please take a moment to review these major points before you continue with
the next topic.
• At the beginning of each shift, all vehicles used on the job site must be
checked for safe operating condition and for damage that could cause
failure while in use.
• Earth movement vehicle specifications cover:
1. Emergency access ramp and berms constructed to restrain and
control runaway vehicles
2. Service braking systems capable of stopping and holding fully
loaded equipment
3. Horns distinguishable from the surrounding noise level for all bidirectional machines, such as rollers, compacters, front-end
loaders, bulldozers, and similar equipment
4. Reverse signal alarms distinguishable from the surrounding noise
level, or an employee signaling safe conditions before earthmoving
or compacting equipment with an obstructed rear view is used in
reverse gear
5. Guarded scissor points on all front-end loaders to protect the
operator during normal operation
6. Seat belts on all equipment listed in this topic
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Powered industrial trucks must meet the following general requirements:
o The rated capacity clearly posted on the vehicle and not exceeded
o Manufacturer's written approval before modifying or adding
affecting anything that affects the capacity or safe operation of the
equipment
o If two or more trucks lift a load by working in unison, the
proportion of the total load carried by any one truck not exceeding
its capacity
o Steering or spinner knobs not attached to the steering wheel
unless the steering mechanism prevents road reactions from
causing the steering handwheel to spin
o A safe place to ride provided where riding of trucks is authorized
o Rollover guards on all site-clearing vehicles and rider-operated
equipment equipped with overhead and rear canopy guards as
specified in this topic
Topic 2: Manual on Uniform Traffic Control Devices
Vehicles and equipment operating in and around the work zone are involved in
over half of the worker fatalities in this industry.
This lesson addresses the OSHA safety requirements for operating vehicles
and equipment within an off-highway job site not open to public traffic.
However, since OSHA does not cover machinery types or safety equipment
exhaustively (nor does it address work practices, traffic control plans, or shift
work), another source must be consulted.
The Manual on Uniform Traffic Control Devices (MUTCD) more clearly defines
applicable standards in these OSHA-omitted areas. By following these
combined specifications, the industry believes it can minimize the confusion of
motorists passing through the work zone and limit collisions involving
motorists and workplace vehicles.
Upon completing this topic, you will be able to:
• Explain the purpose of the MUTCD
• Name the two primary causes of death and injury on roadway
construction sites
• Describe the types of measures the MUTCD addresses concerning:
o Work zone layout
o Temporary traffic control devices
o Motorist education and speed enforcement
o Flaggers
o High-visibility apparel
Defining the Hazards
Each year, more than 100 workers are killed and over 20,000 are injured in
the highway and street construction industry.
Highway and street construction workers risk fatal and serious nonfatal injury
when working in the vicinity of passing motorists, construction vehicles, and
Historically, efforts to reduce vehicle-related worker injuries have focused on
improving traffic control devices and work zone configurations to minimize
confusion of motorists passing through the work zone and to limit collisions
involving motorists. The premise was that, by minimizing traffic collisions in
work zones, worker injuries would be minimized. However, fatality data
indicate that workers struck by motorists passing through work zones account
for only half the vehicle-related fatalities among highway workers.
Workers in highway work zones are exposed to risk of injury from the
movement of construction vehicles and equipment within the work zones, as
well as from passing motor vehicle traffic. Recent data from the Census of
Fatal Occupational Injuries (CFOI) indicate that of the 841 work-related
fatalities in the U.S. highway construction industry, 465 (55 percent) were
vehicle- or equipment-related incidents that occurred inside a work zone.
How Are Workers Exposed?
Highway workers routinely work near construction vehicles and motor vehicle
traffic. Flaggers and other workers on foot are exposed to the risk of being
struck by traffic vehicles or construction equipment if they are not visible to
motorists or equipment operators. Workers who operate construction vehicles
or equipment risk injury due to overturn, collision, or being caught in running
equipment. Highway workers, regardless of their assigned task, work in
conditions of low lighting, low visibility, and inclement weather and may work
in congested areas with exposure to high traffic volume and speeds.
What Is Being Done?
The Federal Highway Administration has developed and maintained the Manual
on Uniform Traffic Control Devices (MUTCD), which provides standards for
uniform design and setup of highway work zones. The primary focus of Part 6
of the MUTCD is the interaction between the road user and the work zone. The
MUTCD contains exhaustive specifications for signage, pavement and curb
markings, traffic signals, and marking of school zones, bicycle facilities, and
highway-rail crossings. It also prescribes temporary traffic control measures
for numerous scenarios involving lane closures, lane shifts, detours, shoulder
work, median crossovers, mobile operations, and blasting. The MUTCD
addresses topics such as training, personal protective equipment, speed
reduction, barriers, and lighting as they apply to highway construction.
Flagging and signaling practices are discussed in general terms in Subpart G,
which covers signs, signals, and barricades. Subpart G defers to the MUTCD on
matters relating to hand signals, barricades, and traffic control devices.
Construction contractors, contracting agencies, and others responsible for
work zone safety face the challenge of providing a safe workplace while
ensuring the safe movement of the public through the work zone. Highway
and street construction presents a complex work situation in which workers
face multiple injury risks under conditions that may change without warning.
Incidents
Hazards that face highway workers rise as bad weather, night work, and speed
combine.
Highway workers risk injury from passing traffic vehicles.
An 18-year-old flagger, outfitted in full reflective vest, pants, and hard hat,
was directing traffic at one end of a bridge approach during a night milling
operation. The work zone was correctly marked with cones and signs, and the
entire bridge was illuminated with streetlights. The flagger was standing under
portable floodlights in the opposing traffic lane close to the centerline, facing
oncoming traffic. A pickup truck traveling in the wrong lane at an estimated 55
to 60 miles per hour struck the flagger head on and carried him approximately
200 feet. He died at the scene of multiple traumatic injuries.]
Injury from construction equipment operating inside the work zone.
A 33-year-old construction laborer was working at a gravel-unloading
operation at a highway construction site. Usually he operated the generator for
the conveyor system that moved gravel unloaded from belly dump trailers. A
dump truck driver on the site was having difficulty opening the gates of his
belly dump trailer. Attempting to assist the driver, the laborer went under the
trailer to open the gates manually. The driver, not realizing the laborer was
under the trailer, pulled away from the unloading platform and ran over him
with the rear dual tires of the trailer. The laborer was pronounced dead at the
scene.
Injury from construction vehicles entering and leaving the work zone.
An 11-person construction crew was paving the northbound side of a six-lane
interstate highway. The far left and middle lanes of the highway were closed to
traffic, with two pavers operating simultaneously in staggered positions. Hot
asphalt was delivered to the site in tractor-trailers that queued on the left
shoulder while waiting to back up to the pavers. A 34-year-old construction
laborer was positioned adjacent to the far left lane, approximately 12 feet
behind the paver's work area, shoveling old asphalt from around a catch basin.
A tractor-trailer pulled away from the paver in the middle lane and began
backing. The driver stopped when he heard other workers yelling. Exiting the
vehicle, he found the laborer run over by the four left rear wheels. The laborer
was pronounced dead at the scene.
Regulations for Worker Protection
To combat the hazards just described, the Manual on Uniform Traffic Control
Devices (MUTCD) provides for uniform design and setup of highway work
zones nationwide and includes guidance for developing temporary traffic
control plans (TCPs) that determine the flow of traffic through work zones.
Compliance with the MUTCD and OSHA regulations is a necessary first step in
providing a safe work environment. However, these sources, taken together,
do not provide comprehensive guidance to ensure worker safety in highway
work zones.
The following list shows items that are not covered by either set of
regulations:
• Safety of all workers on foot around traffic vehicles
• Safe operation of construction vehicles and equipment in highway work
zones
• Planning for safe operations within work zones
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Special safety issues associated with night work in highway construction
Safety on highway work sites is a concern for all involved. Click the
forward arrow to see what steps can be taken by the various groups on
site.
Work Zone Layout
The Manual on Uniform Traffic Control Devices specifies the responsibilities of
those involved in assuring the safety of the work zone layout.
Road builders and maintainers can:
• Assign a traffic control supervisor who is knowledgeable in traffic control
principles overall and is responsible for the safety of the work zone setup
• Include employees in the walk- or drive-through as a training tool and to
emphasize that safety is a continuous priority
• Authorize the traffic control supervisor to temporarily halt work until
unsafe conditions related to temporary traffic control have been
eliminated
• Document work zone setup and changes throughout the course of the
project and retain these records in a "job file" as a reference for future
jobs
• To the extent practical, keep the length of the work zone appropriate to
the work in progress so that motorists do not increase speed after
passing through a long stretch with no sign of work activity
Contracting agencies can:
• Establish a streamlined process for reviewing and approving changes in
the work zone setup that are necessitated by safety concerns
• Close the road completely and reroute traffic where feasible
• Provide alternative transportation modes and alternative routes for road
users
• Minimize worker exposure to traffic hazards on interstate and similar
roadway systems by forcing traffic moving in both directions onto one
side of the road and completely closing off the work space
• Specify the use of temporary pavement markings to move the traffic
lane laterally away from the workspace on projects lasting less than two
weeks
• For night work, specify:
o Increased taper length
o Low-level transitional lighting installation in advance warning areas
and termination areas to ease motorists' adjustment to changing
lighting conditions.
Road builders, maintainers and contracting agencies can:
Cooperate to design and implement traffic control plans according to safety
management principles that call for a hierarchical approach to preventing
worker injuries:
• Reduce worker exposure to injury to the extent possible.
• Where worker exposure to traffic cannot be completely eliminated, use
positive protective barriers to shield workers from intrusion by traffic.
• Where installing temporary traffic barriers is impractical or creates a
greater hazard, install channelizing devices such as traffic cones and
barrels to delineate the work zone.
• Consider additional measures such as sensors, handheld radios, and
intrusion alarms, but do not rely on them as a primary protection
against injury.
Temporary Traffic Control Devices
Traffic control devices are important because they optimize traffic
performance, promote uniformity throughout the country, and help improve
safety by reducing the number and severity of traffic crashes.
Road builders and maintainers can:
• Use temporary traffic control devices, such as signage, warning devices,
paddles, and concrete barriers, in a consistent manner throughout the
work zone
• Set up temporary traffic control within a reasonable time prior to
construction so that motorists do not become complacent and ignore
warning signs and devices when work begins
• Provide flaggers with devices that increase their visibility to passing
motorists and construction vehicles (One effective field-tested example
is the flashing slow/stop paddle, a standard paddle with a strobe light
mounted on its face.)
• Keep channelizing devices clean and properly maintained to preserve
their reflective intensity and visibility
• Ensure that all traffic control devices are operating properly and in place
at all times (Missing traffic control devices create the potential for
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motorists to inadvertently enter the workspace or exit the highway in
the wrong place.)
For night work:
o Reduce spacing between channelizing devices to compensate for
reduced driver visibility
o Ensure arrow panels are set at nighttime levels; daytime settings
used at night produce blinding light
o Increase the size of traffic control devices, reflective material, and
lettering to improve driver recognition
Contracting agencies can:
• To better delineate highway exits in work zones, consider specifying a
different color for channelizing devices and signs intended to guide
motorists off the exit ramp
• Create positive separation between the traveling public and workers by
specifying:
o Use of temporary traffic barriers whenever possible -- paint
barriers a color that contrasts with the background and install
reflectors, lights, or light tubes on barriers to further enhance
delineation
o Use of truck-mounted attenuators (TMAs) for a wider range of
work zone safety applications -- TMAs can be placed on the
upstream, lateral, or downstream sides of traffic flow to physically
isolate the work space and may be particularly useful in moving
work zones, where they can move forward as work progresses to
protect workers from being struck from behind by traffic vehicles
Motorist Education and Speed Enforcement
Motorists may be more cautious of speed and hazards ahead if they are
informed of up-to-date worksite locations and are offered alternative travel
advice.
Road builders, maintainers, and contracting agencies can:
• Give motorists plenty of advance warning of upcoming work zones
• Ensure that motorists have real-time information in signage and in
traveler's advisory radio broadcasts
• Install warning signs that provide estimated time of delay and other road
closure information so that drivers have sufficient opportunity to exit
and take a different route
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Use a combination of traffic queue detection equipment and dynamic
message signs to vary messages as traffic conditions change
Keep warning sign messages simple and brief
Cover or take down warning signs when workers are not present
Remove channelizing devices when they are no longer needed
Additionally contracting agencies can:
• Follow the MUTCD recommendation that zoning for reduced speed
should be avoided as much as practical
• In highly vulnerable situations that threaten worker safety, consider
reducing speed by requesting that appropriate municipal authorities
authorize the area for reduced speed in the construction zone. Use
police, funneling, lane reduction, flashing lights, or flaggers. (Speed
reductions should be applied incrementally to maintain uniform traffic
flow. Normal speed limits should be restored when work is no longer in
progress, when workers are no longer at the job site, or when hazards
have been removed or protected.)
• Use an advance media campaign to advise the public of upcoming road
work
Flaggers
The job of a flagger is very hazardous, so flaggers should not be the primary
solution to traffic management problems on the worksite. To manage these
hazards, it is very important that all involved follow these guidelines.
Road builders and maintainers can:
• Use alternative traffic management systems such as lane shifts, portable
traffic signals, or remote signaling devices operated by workers away
from the flow of traffic
• Use alternatives to flaggers when traffic control is required under
hazardous conditions such as high traffic speeds, inclement weather,
night work, and other conditions that limit visibility
• When flaggers are used, train them all according to their level of
responsibility and work zone conditions; flaggers should know the traffic
flow, the work zone setup, and proper placement of channelizing devices
• Assign each flagger the responsibility for monitoring operations in his or
her immediate work area
• Authorize flaggers to recommend temporarily halting worksite operations
to the traffic control supervisor when they see a hazard threatening the
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safe movement of traffic through the workzone and authorize them to
notify the supervisor when the hazard is corrected
Authorize flaggers to halt operations in the event a hazard arises and
the traffic control supervisor is not in the immediate area
Train flaggers to maintain sufficient distance from other highway
workers, so that passing motorists can identify workers
When multiple flaggers are required, ensure they have the appropriate
sight distance or two-way radios to communicate effectively
Avoid using flaggers whenever possible.
High-Visibility Apparel
Retroreflective material reflects vehicle headlights so that signs, safety
clothing, and other safety devices appear more visible to drivers at night.
Fluorescent materials and colors that do not blend into the background are
standard for anyone working on road and highway areas.
Road builders and maintainers can:
• Require all workers on foot to wear high-visibility safety apparel
• Inspect high-visibility clothing regularly to ensure that color has not
faded and that retroreflective properties have not been lost
• Consider seasonal variations in landscape and foliage when choosing
colors for worker apparel, preventing workers from blending into the
background and decreasing the threat from motorists, other workers,
and worksite vehicles
• Consider using fluorescent garments with retroreflective material when
working under poor lighting conditions
• Consider increasing visibility by using high-visibility armbands and hats
and vests with strobes
Contracting agencies can:
Require fluorescent and retroreflective materials on headgear and on flaggers'
gloves.
Topic Summary
Please take a moment to review these major points before you continue with
the next topic.
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The two primary sources of death and injury to highway construction
workers are from highway motorist vehicles and other construction
vehicles.
Low visibility increases the risk to flaggers and other workers on foot
being struck by traffic vehicles or construction equipment.
Workers who operate construction vehicles or equipment risk injury due
to overturn, collision, or being caught in running equipment.
The Manual on Uniform Traffic Control Devices (MUTCD) provides for
uniform design and setup of highway work zones nationwide and
includes guidance for developing temporary traffic control plans (TCPs)
that determine the flow of traffic through work zones.
Safety to highway construction site workers can be improved by
following government regulations on work zone layout, temporary traffic
control devices, motorist education and speed enforcement, safe
conditions for flaggers, and high-visibility apparel summarized in this
topic from the MUTCD.
Topic 3: Special Equipment
This topic covers the requirements for the safe operation and training for
operators of skidsteer loaders and powered industrial trucks.
Upon
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completing this topic, you will be able to:
Define regulations covering a skidsteer loader
Define regulations covering powered industrial trucks
List the dos and don'ts for safe entry and exit of a loader
Define the term interlocked controls
List the components of ROPS devices on special equipment such as
loaders
• Describe the three ways seat belts protect operators
Skidsteer Loaders
Skidsteer loaders put workers at risk of rollover and runover incidents.
Additionally, workers are exposed to other risks of injury from some of the
features of this equipment. The compact nature of the machine places the
operator close to the zone of movement for the liftarms.
For example, the operator's seat and controls are between the liftarms and in
front of the liftarm pivot points. This design requires operators of skidsteer
loaders to enter and exit the loader through the front of the machine and over
the bucket. A worker who does not enter or exit properly can activate a foot or
hand control and may cause movement of the liftarms, bucket, or other
attachment. Such an incident can cause death or serious injury.
Loaders
The SAE, however, has developed a manufacturers' standard for the American
National Standards Institute (ANSI) addressing skidsteer loaders. The SAE
standard SAE J1388 contains design guidelines that address machine rollovers
and the hazards of pinning between the liftarms and frame and between the
bucket and frame.
To conform with this recommended practice, manufacturers must:
• Provide warnings, operator instructions, and service procedures
• Equip the machine with seat belts
• Provide a means to prevent the liftarms from lowering when the
operator is entering or exiting the machine
• Provide handholds and steps to facilitate entry to and exit from the
loader
• Provide ROPS with side screens
• Provide two openings for emergency exit
• Provide safety signs and instructions to warn of hazards during normal
operations and servicing
Construction workers and their employers can reference these standards to
verify that equipment used on the worksite is maintained according to ANSI
requirements.
To keep workers from unintentionally activating controls, manufacturers of
skidsteer loaders began to equip them with interlocked control systems in the
early 1980s. These interlocked controls require that a nonoperational control
or fixture (such as a seat belt or restraint bar) be secured or activated before
operational controls can function. Some machines connect the liftarm control
to the seat belt to prevent movement of the liftarms unless the seat belt is
fastened. Other machines connect the liftarm control to a bar that must be
lowered in front of the operator or to a pressure switch in the seat. Recently
manufacturers have introduced electronic systems to perform the interlocking
function.
Skidsteer loaders now come equipped with rollover protective structures
(ROPS), side screens, and seat belts to protect the operator if the machine
turns over. The side screens prevent the operator from coming into contact
with moving liftarms.
Entering And Exiting Safely
Rules for entering:
• Enter only when the bucket or other attachment is flat on the ground or
when the lift-arm supports are in place. Use supports supplied or
recommended by the manufacturer.
• When entering the loader, face the seat and keep a three-point contact
with handholds and steps.
• Never use foot or hand controls for steps or handholds.
• Keep all walking and working surfaces clean and clear of debris.
Rules for exiting the operator's seat:
• Lower the bucket or other attachment flat to the ground.
• Set the parking brake.
• Turn off the engine.
If exiting through the front of the machine is not possible, use the emergency
exit through the roof or across the back.
Manufacturers' Safety Devices
All safety devices provided by manufacturers should be regularly inspected
and maintained. Here are tips for use and maintenance:
Liftarm supports: Use the liftarm supports provided by or recommended by
the manufacturer when working or moving around the machine with the
bucket in a raised position while the controls are unattended.
Currently manufactured machines now have either the pintype supports
(which can be operated from inside the operator's cab) or the strut-type
supports (which may also be operated from inside the cab or may require the
help of a co-worker).
If the machine is not equipped with liftarm supports, contact the equipment
dealer or manufacturer's representative for help in selecting proper support
procedures. Never use concrete blocks as supports. They can collapse under
even light loads. Hoists and jacks used for support must be free of defects
such as bent, cracked, or twisted parts or pinched, frayed, or twisted cable.
They must also be capable of supporting the load.
Interlocked controls: Regularly inspect and maintain interlocked controls in
proper operating condition.
These systems require the operator to be properly positioned and restrained
before the loader can be used. Make sure that the seat belt is always securely
fastened around the operator when the loader is in operation. Always use
restraint bars if they are provided.
Never bypass or defeat interlocked controls.
Although workers and employers may perceive safety features such as
interlocked controls and seat belts as obstacles to efficient machine operation,
bypassing these devices increases the risk of death or serious injury.
Seat belts: Make sure that the seat belt is secured around the operator
whenever the seat is occupied. The seat belt protects the operator in several
ways:
• If seat belts are part of the interlocked control system, they protect
workers from being caught and crushed between the liftarms and frame.
• During rollovers, the seat belt keeps the operator within the protective
envelope of the ROPS.
• The seat belt can also protect the operator from leaning or being jostled
into the operating zone of the liftarms and bucket.
Retrofit packages: If side screens, interlocks, ROPS, and seat belts are not
present, contact the equipment dealer or manufacturer's representative about
the availability of retrofit packages or replacement parts.]
Maintaining Safe Operating Conditions
Follow the manufacturer's instructions for maintaining the loader. Keep the
foot controls and the operator's compartment free of mud, ice, snow, and
debris.
Before servicing the loader:
• Set the parking brake.
• Lower the bucket or other attachment flat to the ground.
• Turn off the engine.
• Remove the key from the switch.
If the machine cannot be serviced with the bucket on the ground, use the
liftarm supports recommended or provided by the manufacturer. If the
machine is not equipped with liftarm supports, contact the equipment dealer
or manufacturer's representative for help in selecting proper supports.
Never work on the machine with the engine running unless directed to do so
by the operator's manual. Follow the manufacturer's safety recommendations
to complete the task. If the adjustments require that the engine be in
operation, use two persons to perform the task.
Loader Training
Operators and workers who service the loaders must be trained to read and
follow the manufacturer's operating and service procedures given in the
operator's manuals and on the loader's warning signs. For help with such
training, contact the equipment manufacturer. Obtain manuals, instructional
videos, and operator training courses from the equipment dealer or
manufacturer.
If you are an employer, make sure that your workers understand all
manufacturers' warnings and instructions before they operate skidsteer
loaders. Train workers to use the following safe operating procedures:
• Operate the loader from the operator's compartment, never from the
outside.
• Stay seated when operating the loader controls.
• Work with the seat belt fastened and the restraint bar in place.
• Keep your arms, legs, and head inside the cab while operating the
loader.
• When possible, plan to load, unload, and turn on level ground.
• For maximum stability, travel and turn with the bucket in the lowest
position possible.
• Never exceed the manufacturer's recommended load capacity for the
machine.
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Operate on stable surfaces only.
Avoid traveling across slopes; travel straight up or down with the heavy
end of the machine pointed uphill.
Always face the direction of travel.
Keep bystanders away from the work area.
NEVER modify or bypass safety devices.
Forklifts
The American Society of Mechanical Engineers (ASME) defines a powered
industrial truck as a mobile, power-propelled truck used to carry, push, pull,
lift, stack, or tier materials. Powered industrial trucks, more commonly known
as pallet trucks, rider trucks, forktrucks, or lifttrucks, can be ridden or
controlled by a walking operator. They can be powered through electric or
combustion engines and are designed for a variety of applications.
American industry currently has more than 998,000 powered industrial trucks.
OSHA estimates that industrial truck incidents cause roughly 101 fatalities and
94,570 injuries annually.
Training Program Implementation
Individuals who have the knowledge, training, and experience to train and
evaluate potential operators must conduct all operator training and evaluation.
Training will include a combination of formal instruction, demonstrations, and
practical exercises performed by the trainee, and an evaluation of the
operator's performance. Practical exercises must be performed under the
direct supervision of trainers in a location where the practical training does not
endanger the trainee or other employees.
A training program for forklift operators must give initial instruction in these
truck-related and workplace-related topics:
Truck-Related
• Operating instructions, warnings, and precautions for the type of truck
• Similarities to and differences from automobiles
• Control and instrumentation location and use
• Engine or motor operation
• Steering and maneuvering
• Visibility
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Fork and attachment limitations and use
Vehicle capacity
Vehicle stability
Vehicle inspection and maintenance
Refueling or charging batteries
Operating limitations
Other operating instructions, warnings, or precautions listed in the
operator's manual
Workplace-Related
• Surface conditions where the truck is used
• Load composition and stability
• Load stacking, unstacking, and transport
• Pedestrian traffic
• Narrow aisle and restricted area operation
• Operation in hazardous locations
• Ramp and sloped surface operation
• Unique or potentially hazardous conditions
• Operating the vehicle in closed environments
Training must be specific to the operating characteristics of the specific
powered industrial truck (same manufacturer and model) the employee will be
using.
Expectations of Training
The employer must ensure that every powered industrial truck operator is
competent in the operation of that truck prior to operating it. Proof of
competence is the successful completion of the required training.
Each powered industrial truck operator must have his performance evaluated
every three years. Refresher training should be conducted so employees retain
the ability to safely operate an industrial truck. Retraining should also be used
if it is believed that unsafe acts have been committed, an accident or near
miss occurs, an evaluation reveals a deficiency, the operator is assigned to a
different type of truck, or a workplace condition changes that would affect
truck operation.
Certification: The employer must certify that every operator has received
appropriate training, has been evaluated, and has demonstrated competency
in performing the operator's duties. Certification includes the name of the
trainee, date of training, and signature of the designated evaluator
When Training Is Unnecessary: If a current or new truck operator has been
trained in any of the required training elements and is authorized to operate a
specific truck in a specific environment, the operator does not need to be
retrained in these elements if the employer certifies the operator is competent.
What is the stability triangle?
The majority of counterbalanced industrial trucks have their weight supported
on three points. Even on a four-wheeled truck, the front two drive wheels are
two points on the stability triangle, while the back two steering wheels (which
are connected on a central pivot) support the weight at the rear and make the
third point. When these three points are connected with imaginary lines, the
stability triangle is formed.
The stability triangle is useful in explaining the stability of a powered industrial
truck. An unloaded truck on a level surface will have a center of gravity in the
middle of the stability triangle. As a load is added to the truck, or when the
truck is on an inclined surface, the center of gravity will move within the
stability triangle. If the center of gravity moves outside of the stability
triangle, the truck will tip over.
Rollover Protective Structures (ROPS)
Some material handling equipment by its design is susceptible to rollover
incidents. Special structures are provided on such equipment to protect the
occupant from injuries in these incidents. The following devices generally have
these structures:
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All rubber-tired, self-propelled scrapers
Rubber-tired front-end loaders
Rubber-tired dozers
Wheel-type agricultural and industrial tractors
Crawler tractors
Crawler-type loaders
Motor graders, with and without attachments
OSHA standards provide that material handling machinery equipment
manufactured on or after September 1, 1972, must be equipped with rollover
protective structures (ROPS) that meet the minimum performance standards
prescribed by OSHA, as applicable. All material handling equipment
manufactured or placed in service (which means owned or operated by the
employer) prior to September 1, 1972, must be fitted with ROPS.
If a rollover protection structure is removed for any reason, it must be
remounted with equal or better quality bolts or welding as required for the
original mounting.
Each ROPS must have the following information permanently affixed to the
structure:
• Manufacturer or fabricator's name and address
• ROPS model number, if any
• Machine make, model, or series number that the structure is designed to
fit
Topic Summary
Please take a moment to review these major points before you continue with
the next topic.
• Skidsteer loaders put workers at risk of rollover and runover incidents.
• Skidsteer loaders have required interlocked controls since the early
1980s. These controls specify that a nonoperational control or fixture
(such as a seat belt or restraint bar) be secured or activated before
operational controls can function.
• Manufacturers now have electronic systems to perform the interlocking
function. Skidsteer loaders are now equipped with rollover protective
structures (ROPS), side screens, and seat belts to protect the operator if
the machine turns over.
• Never use concrete blocks as liftarm supports on loaders.
• Never bypass or defeat interlocked controls.
• When entering a loader:
o The bucket or other attachment should be flat on the ground or the
liftarm supports in place.
o Use supports supplied or recommended by the manufacturer.
o Face the seat and keep a three-point contact with handholds and
steps.
o Never use foot or hand controls for steps or handholds.
o Keep all walking and working surfaces clean and clear of debris.
• When exiting the operator's seat:
o Lower the bucket or other attachment flat to the ground.
o Set the parking brake.
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o Turn off the engine.
• Before servicing the loader:
o Follow manufacturer's recommendations.
o Set the parking brake.
o Lower the bucket or other attachment flat to the ground.
o Turn off the engine.
o Remove the key from the switch.
Seat belts as part of the interlocked control system can protect workers
from being caught and crushed between the liftarms and frame; keep the
operator within the ROPS during rollovers and protect the operator from
leaning or being jostled into the operating zone of the liftarms and bucket.
Forklift training and certification is required for all operators.
Each ROPS must have the manufacturer's or fabricator's name and address,
model number, machine make, model, or series number that the structure
is designed to fit permanently affixed to the structure.
Topic 4: Commercial Driver's License
This topic introduces areas of training for the operation of motor vehicles
needed in the construction industry. Upon completing this lesson, you will be
able to:
• Describe areas of testing and licensing commercial motor vehicle drivers
require
• Explain the five types of training each hazmat employee must receive
CDL Policies
The Federal Highway Administration develops, issues, and evaluates national
standards for testing and licensing commercial motor vehicle drivers. These
standards require states to issue a commercial driver's license only after
drivers pass knowledge and skill tests that pertain to the type of vehicle
operated. States are audited every three years to monitor compliance with
federal standards; noncompliance could result in loss of federal funding.
An important element for commercial drivers in the construction industry is
the regulations involved in working with and transporting hazardous materials.
Hazardous Materials Transport
Congress gives the U.S. Department of Transportation (DOT) the authority to
"...issue regulations for the safe transportation of hazardous materials in
intrastate, interstate and foreign commerce." This authority was granted in the
Hazardous Materials Transportation Act (HMTA), first adopted in 1974 and
amended in November, 1990, as the Hazardous Materials Transportation
Uniform Safety Act of 1990 (HMTUSA).
In response to this mandate, the DOT now has compiled a body of rules called
the Hazardous Materials Regulations (HMR), maintained by the Research and
Special Projects Administration (RSPA).
To better understand the provisions of these regulations, it is important to
understand the meaning of the definitions specified in the act.
What is training?
Training, as defined in the Hazardous Materials Transportation Act
(HMTA), is a systematic program that ensures a hazmat employee:
• Is familiar with the general provisions of the Hazardous Materials
Regulations (HMR)
• Is able to recognize and identify hazardous materials
• Has knowledge of specific requirements of these hazardous materials
regulations applicable to the functions performed by the employee
• Has knowledge of emergency response information, self-protection
measures, and incident prevention methods and procedures
Who is a hazmat employer?
A hazmat employer is a person (including a business or organization) that
uses one or more of its employees in connection with:
• Transporting hazardous materials in commerce
• Causing hazardous materials to be transported or shipped in commerce
• Representing, reconditioning, marking, testing, certifying, repairing,
selling, modifying, or offering containers, drums, or packaging to qualify
them for use in the transportation of hazardous materials
Who is a hazmat employee?
A hazmat employee is a person employed by a hazmat employer and who, in
the course of employment, directly affects hazardous materials' transportation
safety.
General Training Requirements
General awareness/familiarization training
General awareness/familiarization training is designed to provide familiarity
with DOT regulations for shippers, transporters, and manufacturers and to
enable the employee to recognize and identify hazardous materials consistent
with the hazard communication standards of the DOT regulations.
Function-specific training
Function-specific training relates to the requirements of DOT regulations for
shippers, transporters, and manufacturers that are specifically applicable to
the functions the employee performs.
Safety training
Safety training must cover:
• Emergency response information required by 49 CFR Part 172, Subpart
G-Emergency Response Information
• Measures to protect the individual employee from the hazardous
materials to which he or she may be exposed in the workplace
• Specific measures the hazmat employer has implemented to protect
employees from exposure
• Methods and procedures for avoiding incidents, such as the proper
procedures for handling packages containing hazardous materials
• Testing of each of the employer's hazmat employees by appropriate
means
Initial and Recurrent Training
A new hazmat employee or a hazmat employee who changes job functions
must complete training for the new job function(s) within 90 days. However,
the employee may perform new hazardous materials job functions prior to the
completion of training if the employee performs those functions under the
supervision of a properly trained and knowledgeable hazmat employee.
Hazmat employees must receive the required training at least once every
three years.
Driver Training and Record Keeping
In addition to the generalized training, drivers of hazardous materials are
required by 49CFR 177.816 regulations that ..."no carrier may transport, or
cause to be transported, a hazardous material unless each hazmat employee
who will operate a motor vehicle has been trained in the applicable
requirements of 49CFR Parts 383, 387, 390-399 and the procedures necessary
for the safe operation of that motor vehicle."
Training Records
Each hazmat employer must create and retain a record of current training for
each hazmat employee. The record must include information for at least the
last three years. This record must be retained for as long as that employee
works as a hazmat employee and for 90 days thereafter.
The training records must include the following information:
• Hazmat employee's name
• Most recent training completion date
• Description, copy of, or location of training materials used
• Name and address of the person providing the training
• Certification that the hazmat employee has been trained and tested as
required
Hazard communication training required by the OSHA may be used to satisfy
the DOT safety training requirements if the training addresses the DOT safety
training elements. The hazmat employer or certain other public or private
sources can provide the required training.
Which employees require hazmat training?
Employees who:
• Determine if a material is a hazardous material
• Design, produce, and/or sell packaging for hazardous materials
• Determine proper packaging for hazardous materials
• Put hazardous materials into packaging
• Mark and/or label hazardous materials packages
• Fill out shipping papers for hazardous materials
• Load or unload hazardous materials
• Operate vehicles that transport hazardous materials
Topic Summary
Please take a moment to review these major points before you continue with
the next topic.
• A hazmat employee is a person employed by a hazmat employer and
who, in the course of employment, directly affects hazardous materials'
transportation safety.
• Training required by the Hazardous Materials Transportation Act (HMTA)
is a systematic program that ensures a hazmat employee:
o Is familiar with the general provisions of the Hazardous Materials
Regulations (HMR)
o Is able to recognize and identify hazardous materials
o Has knowledge of specific requirements of these hazardous
materials regulations applicable to the functions performed by the
employee
o Has knowledge of emergency response information, self-protection
measures, and accident prevention methods and procedures
• A hazmat employer is a person (including a business or organization)
that uses one or more of its employees in connection with:
o Transporting hazardous materials in commerce
o Causing hazardous materials to be transported or shipped in
commerce
o Representing, reconditioning, marking, testing, certifying,
repairing, selling, modifying or offering containers, drums, or
packaging to qualify them for use in the transportation of
hazardous materials
• Hazmat training record must include information for at least the last
three years and be kept for as long as that employee works as a hazmat
employee and for 90 days thereafter.
Lesson Summary
This lesson contained information and instruction about motor vehicles. By
completing this lesson, you should have the knowledge to discuss the following
topics. Take a moment to see if you can do the following:
• Describe general safety requirements for all motor vehicle construction
equipment
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Explain the role of the Manual on Uniform Traffic Control Devices in
occupational safety
List the dos and don'ts for safe entry and exit of a loader
Describe areas of testing and licensing required for commercial motor
vehicle drivers
Excavation
Introduction
Excavation and trenching procedures are performed thousands of times a day across
the United States. This illustration contains hazardous situations.
OSHA estimates that about 60 people are killed in trenching accidents each year, and
6,400 workers are seriously injured in trench cave-ins.
Before you take the first step in digging, be sure to review the crucial safety
guidelines covered in this lesson. That's why you need to understand trench hazards
and know how to prevent cave-ins.
Lesson Overview
This lesson highlights the requirements in the updated standard for excavation and
trenching operations, provides methods for protecting employees against cave-ins,
and describes safe work practices for employees. Upon completing this lesson, the
learner will be able to:
• Identify and minimize excavation hazards
• Outline OSHA's requirements and support systems for trenches and excavation
• Manage controls and other procedures and protective systems designed to
protect workers in or around an excavation
• Prevent other types of common surface and trench incidents
• Plan and train the work force in the recognition, identification, evaluation, and
control of excavation hazards
Why Learn This Lesson?
Excavating is one of the most hazardous construction operations. OSHA's Subpart P,
Excavations, of 29 CFR 1926 was developed to make the standard easier to
understand, permit the use of performance criteria where possible, and provide
construction employers with options when classifying soil and selecting employee
protection methods.
Excavation and trenching procedures are performed thousands of times a day across
the United States. Unfortunately, about 60 people are killed in trenching accidents
each year. Contractors and workers should understand the laws and regulations
applicable to excavation and trenching occupations. These statutes are in effect for
the express purpose of protecting those who work in excavation and trenching
situations.
Excavations do not have to be large or deep to create life-threatening hazards.
Recognizing these hazards is the first step in eliminating or controlling them.
This lesson will help your workers fully understand the dangers and present simple
safety steps that can be taken to keep your job site from becoming one of the
statistics.
Topic 1: Hazards
Excavation and trenching are extremely hazardous operations that expose workers to
the possibility of serious injury or death. This topic covers common excavation
hazards and will help employers and workers prevent incidents on the job. Upon
completing this topic, you will be able to:
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•
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Recognize excavations as extremely hazardous operations
Categorize the three types of soil
Identify the contributing factors to cave-ins
Explain the characteristics of soil mechanics
Cave-Ins
The greatest hazard associated with trenching is the cave-in of the surrounding soil
on workers in the trench, the result often being fatal. Other hazards involved in
trenching include falls, confined spaces, and exposure to underground utilities such as
gas, steam, and electricity. Employees involved in excavation operations should know
how to minimize these hazards.
Most workers caught in cave-ins are seriously hurt. A cubic yard of hard, compact soil
is extremely heavy and can weigh as much as 4,200 pounds. Many victims are
suffocated after being buried in a cave-in. Survivors often receive severe crushing
injuries. Once a trench or excavation begins to cave in, workers may have only
seconds to escape. This is why careful planning and worker training is so important.
Soil mechanics and physics tell you that, eventually, every excavation and trench will
collapse. Unfortunately, no one can predict when. The factors relating to cave-ins as
shown in the graphic above, vary from site to site, but include:
• Soil type
• Moisture content
• Depth of the excavation or trench and length of time left open
• Vibration
• Adjacent buildings and structures
• Adjacent weight (surcharge)
• Previous disturbances of the soil
•
Weather
Soil Type
The first factor is soil type. The type of soil helps determine how stable the walls of
the excavation or trench will be. The occupational health and safety regulations divide
soil into four types, from Type A (very dense and hard) to Type C (very soft and
loose) and stable rock.
Never count on the soil type alone to protect you, unless it is sound and stable rock.
Soil types may be mixed. Seams of gravel or debris may lie behind seemingly solid
trench walls. The employer and supervisors must therefore assess the soil conditions
carefully before beginning work and take appropriate precautions. If soils are mixed,
always base precautions on the most unstable soil type that could be present -assume the worst.
•
Type A - clay, silty clay, and hardpan (resists penetration). No soil is Type A if
it is fissured, is subject to vibration of any type, has previously been disturbed,
or has seeping water.
•
Type B - medium stability; silt, sandy loam, medium clay, and unstable dry
rock; previously disturbed soils unless otherwise classified as Type C; soils that
meet the requirements of Type A soil but are fissured or subject to vibration.
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Type C - least stable: gravel, loamy sand, soft clay, submerged soil or dense,
heavy unstable rock, and soil from which water is freely seeping.
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Stable Rock - most stable: natural solid mineral material that can be excavated
with vertical sides and will remain intact while exposed. Unstable rock is
considered to be stable when the rock material on the side or sides of the
excavation is secured against caving in or movement by rock bolts or by
another protective system that has been designed by a registered professional
engineer.
•
Layered geological strata - where soils are configured in layers. The soil must
be classified on the basis of the weakest soil layer. Each layer may be classified
individually if a more stable layer lies below a less stable layer; i.e., where a
Type C soil rests on top of stable rock.
Soil Factors
Several other factors contribute to trench cave-ins. In the spring, unshored trench
walls, heavy from rain, can become unstable. Also, when damp soil is exposed to air
during excavation, it can dry out and lose the ability to stand on its own, increasing
the risk that it will slide into the trench. Other factors, such as proximity to highways,
large machinery, backfilled areas, or existing structures can affect soil stability as
well.
Moisture Content
Moisture reduces soil strength. Once a trench or excavation is opened, the walls are
exposed to the elements. Moisture content and soil stability can change rapidly.
Adjacent Weight (Surcharge)
Surcharge is a large weight or load that affects the strength of the trench walls. For
example, spoil piles (excavated earth), mobile equipment, and supplies placed near
the trench put pressure on the walls. Keep surcharges as far away from the
excavation or trench as reasonably practicable.
Vibration and Pressure Reduce Soil Stability
Vibration from compaction activities, equipment operations, nearby traffic, trains, and
so forth often weakens soil stability. The effects increase if the soil is wet or loose.
Previous Disturbances of the Soil
Weather
Rain, melting snow, freezing, flooding, and heat from the sun reduce soil cohesion
quickly.
Other Risks
In addition to soil stability factors presented, there are four more risk issues to
examine.
No Protective Systems
All excavations are hazardous because they are inherently unstable. If they are
restricted spaces, they present the additional risks of oxygen depletion, toxic fumes,
and water accumulation. If you are not using protective systems or equipment while
working in trenches or excavations at your site, you are in danger of suffocating,
inhaling toxic materials, fire, drowning, or being crushed by a cave-in.
Failure to Inspect Trench and Protective System
If trenches and excavations at your site are not inspected daily for evidence of
possible cave-ins, hazardous atmospheres, failure of protective systems, or other
unsafe conditions, you are in danger.
Unsafe Spoil-Pile Placement
Excavated material (spoils) at your site is hazardous if it is set too close to the edge
of a trench/excavation. The weight of the spoils can cause a cave-in, or spoils and
equipment can roll back on top of workers, causing serious injuries or death.
Unsafe Access/Egress
To avoid fall injuries during normal entry and exit of a trench or excavation at your
job site, ladders, stairways, or ramps are required. In some circumstances, when
conditions in a trench or excavation become hazardous, survival may depend on how
quickly you can climb out.
Soil Mechanics
Now that you know soil conditions are a severe cave-in threat when working with
excavation, you will learn the mechanics of soil stability. Let's answer a few basic
questions first.
What is soil?
In excavation and trenching practices, "soil" is defined as any material removed from
the ground to form a hole, trench, or cavity for the purpose of working below the
earth's surface. This material is most often weathered rock and humus known as
clays, silts, and loams, but also can be gravel, sand, and rock. It is necessary to know
the characteristics of the soil at the particular job site.
Who Identifies soil?
Contractors and engineers, who are trained to identify the proper safety protective
devices or procedures needed for each situation, use soils information. OSHA stresses
the need for a "competent person" to be in charge of all excavation and trenching
activities at a job site. Soil scientists and geotechnical specialists can be helpful in
identifying and characterizing soil materials.
What kind of material is soil?
Soil is an extremely heavy material and may weigh more than 100 pounds per cubic
foot. A cubic yard of soil (27 cubic feet of material) may weigh more than 2,700
pounds. That is nearly one and a half tons (the equivalent weight of a car) in a space
less than the size of the average office desk. Furthermore, wet soil, rocky soil, or rock
is usually heavier. The human body cannot support such heavy loads without being
injured.
What are the mechanics of soil?
From a soil mechanics point of view, one can visualize the soil as a series of multiple
columns of soil blocks, with the blocks piled one on top of the other.
In the soil column shown in the picture, each soil block measures one foot square,
weighs approximately 100 lbs, and supports the weight of all of the blocks above.
This means that a block sitting at a five-foot depth supports its own weight and the
combined weight of the four blocks resting on it. The combined weight of this column
is 500 lbs spread over a one-square-foot area. This five-block column constitutes a
500-pound force exerted vertically on whatever lies below.
Forces exerted by a column of soil.
A column of soil exerts not only a vertical force, but also a horizontal force in all
outward directions. The outward force is equal to one-half the vertical force.
For example, the five-block column illustrated in the picture has a downward vertical
force of 500 lbs at the base of soil block number five. The horizontal force pushing out
from the base of that same block is half of 500 lbs, or 250 lbs, in outward directions.
As the weight of the column increases, the soil blocks at the bottom of the column
theoretically have a tendency to compress and spread outward.
In undisturbed soil conditions, this process is stopped by the presence of the
surrounding columns pushing back with equal pressure. These hypothetical columns
press against each other, maintaining equilibrium. Therefore, the horizontal pressures
of all the columns are balanced, producing a stable relationship.
Cave-In Mechanics
An open excavation is an unnatural situation. The average landscape shows no
vertical or near-vertical slopes.
Undisturbed soil may be visualized as an infinite number of columns of soil adjoining
and supporting one another. The system is in equilibrium and is perfectly stable.
When an excavation is cut, the system is disturbed. Lateral stresses that existed on
the excavation wall are removed as the excavation is done. The soil in the excavation
wall immediately begins to move, however slowly, into the excavation.
At the same time the surface of the ground next to the excavation subsides, creating
an unnatural situation. The surface of the ground is in tension, and some of the
weight of the soil in the excavation wall is transferred to the soil back away from the
wall face by a phenomenon called shear.
The combination of tension in the ground surface and shear stress causes cracks to
form from the edge of the excavation. Cracks occur to near the depth of the
excavation back from its edge.
If an excavation 10 feet deep is dug, the cracks may be found somewhere between
three to seven feet back from the excavation edge. There may be several cracks.
They are usually vertical and may be half the depth of the excavation.
When cracks develop, the weight of the soil in the excavation wall is no longer partly
carried by the soil back from the excavation's face.
Then the lower part of the excavation wall fails under the great stress from the
weight of the soil above it. There is no lateral stress to prevent the failure.
When the bottom of the excavation fails, or "kicks," into the excavation, the support
for the upper part of the excavation wall is now essentially hanging only by shear and
tension forces. Failure occurs.
A third cave-in quickly follows. Soil, like concrete, is normally strong in compression,
but not at all strong in tension. Reinforced concrete makes use of the compressive
strength of concrete and the tensile strength of steel. There is no steel in the soil.
Cave-ins generally come in multiples. If the first one doesn't get you, the second one
may, and the third is always a possibility.
This example of the mechanics of a cave-in has offered a discussion of some of the
forces involved in such accidents. It has by no means considered all of the forces that
may be involved in such an occurrence. Weathering, water, vibration, and
superimposed loads may add to the hazardous conditions leading to cave-ins.
Hazards
Some employers and contractors believe that proper safety procedures waste
valuable time and money, and that faster work creates larger profit margins.
However, incidents that occur because safety precautions are not taken can be costly.
In addition to the loss of human life, the possible financial costs of a trenching
accident include:
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Work stoppage to rescue the victim
Additional time and labor to re-excavate the collapsed trench
Workers' compensation costs and increased insurance premiums
Additional paperwork resulting from the investigation of the incident
Topic Summary
Please take a moment to review these major points before you continue with the next
topic.
• Excavations and trenching are extremely hazardous operations that expose
workers to possibly of serious injury and death.
• Soil is divided into four types: Type A, Type B, Type C, and solid rock.
• Factors contributing to cave-ins include soil type, moisture content, depth,
vibration, adjacent structures and weight, previous disturbances, and weather.
• Not planning for protective and inspection systems and unsafe spoil-pile
placement and access present hazardous conditions.
•
Excavation incidents may create large financial losses due to workers'
compensation, insurance premiums, work stoppage, and re-excavation.
Topic 2: OSHA's Requirements
OSHA requires that workers in trenches and excavations be protected and that safety
and health programs address the variety of hazards they face. Upon completing this
topic, learners will be able to:
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Identifying safety precautions for excavations and trenches and requirements
for the competent person
Describe visual and manual testing methods
Explain these three protective systems: slope slides to angle, tabulated data
use, and the trench box
Define OSHA's requirements for temporary and permanent spoils
Discuss OSHA's requirements for benching, sloping, shoring, and shielding
support systems
Explain the employer's responsibility when installing support systems, using
protective equipment, and providing access
Identifying Excavations and Trenches
Cave-ins are perhaps the most feared excavation hazard. But other potentially fatal
hazards exist, including asphyxiation due to lack of oxygen in a confined space,
inhalation of toxic fumes, drowning, etc. Electrocution or explosions can occur when
workers contact underground utilities.
OSHA requires that workers in trenches and excavations be protected and that safety
and health programs address the variety of hazards they face.
Trenches
Exposed trench faces more than five feet high must be stabilized by either shoring,
sloping the face of the wall back to a stable slope, or by some equivalent method to
prevent cave-ins. If the trench is excavated in hard, compact soil materials more than
five feet in depth, the wall must be supported. If the walls of a trench are less than
five feet deep and in soft or unstable soil materials, then trench boxes, shoring,
sheeting, bracing, sloping, or other equivalent methods are required to prevent the
trench wall from collapsing. Trench walls above five feet in height may be sloped
instead of shored.
Materials used for trench boxes, sheeting, sheet piling, bracing, shoring, and
underpinning should be in good condition and should be installed so that they provide
support that is effective to the bottom of the trench. Timber must be sound and free
from large or loose knots. Vertical planks in the bracing system should be extended to
an elevation no less than one foot above the top of the trench face.
When employees are required to be in trenches that are four feet or more in depth,
an adequate means of exit, such as a ladder or steps, must be provided and located
so that no more than 25 feet of lateral travel is required for a person to reach the exit
structure. The trench should be braced and shored during excavation and before
personnel are allowed entry. Cross braces and trench jacks should be secured in true
horizontal positions and spaced vertically in order to prevent trench wall material
from sliding, falling, or otherwise moving into the trench. Portable trench boxes (also
called sliding trench shields) or safety cages may be used instead of shoring or
bracing to protect employees. When in use, these devices must be designed,
constructed, and maintained in a manner that will provide at least as much protection
as shoring or bracing and extended to a height of no less than six inches above the
vertical face of the trench.
During the backfill operation, backfill and remove trench supports together, beginning
at the bottom of the trench. Release jacks or braces slowly and, in unstable soil
materials, use ropes to pull them from above after employees have left the trench.
Excavations
Excavation safety requirements are quite similar to trenching requirements. For
excavations in which employees may be exposed to unstable ground, qualified
personnel using practices that are compatible with standards required by a registered
architect, a registered professional engineer, or other duly licensed or recognized
authority will design support systems such as piling, cribbing, bracing, and shoring
that meet accepted engineering requirements to contain the walls. Excavations with
conditions such as water, silty materials, loose boulders, erosion, deep frost action, or
earth fracture planes require that the slope of the earth adjacent to the excavation be
lessened. Scaling, benching, barricading, rock bolting, wire meshing or other equally
effective means of excavation support must meet accepted engineering requirements
for all sides, slopes, and faces of excavations. Materials used to support excavations
should be maintained in good condition.
Never excavate below the level of the base of the footing or retaining wall, except in
hard rock, unless the wall is underpinned and appropriate precautions are taken to
ensure the stability of adjacent walls. If it is necessary to place or operate power
shovels, derricks, trucks, materials, or other heavy objects on a level above and
adjacent to an excavation, the side of the excavation must be sheet-piled, shored,
braced, or sloped as necessary to resist the additional pressure resulting from such
loads. Install substantial stop logs or barricades when using mobile equipment on or
near an excavation, grade away from the excavation, and provide walkways or
bridges with standard guardrails for employees or equipment to cross over
excavations.
Competent Person
A competent person is one who is capable of identifying existing and predictable
hazards in the surroundings or working conditions that are unsanitary, hazardous, or
dangerous to employees, and who has authorization to take prompt corrective
measures to eliminate them. A competent person should have and be able to
demonstrate the following:
1. Training, experience, and knowledge of:
- Soil analysis
- Use of protective systems
- Requirements of 29 CFR 1926 Subpart P
2. Ability to detect:
- Conditions that could result in cave-ins
- Failures in protective systems
- Hazardous atmospheres
- Other hazards, including those associated with confined spaces
3. Authority to take prompt corrective measures to eliminate existing and
predictable hazards and to stop work when required
Certain activities or safety procedures at a construction site require design,
inspection, or supervision by a competent person. The OSHA Construction Standard
defines a competent person as someone who is:
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Capable of identifying existing and predictable hazards in the surroundings
Capable of identifying working conditions that are unsanitary, hazardous, or
dangerous to employees
Authorized to take prompt corrective measures to eliminate hazards
Excavation and trenching work is dependent on these specialized employees because
its highly technical nature, as well as its inherent hazards, require a greater level of
training and experience than a normal worker would possess.
Testing Methods
The competent person in charge of the excavation must be responsible for
determining the soil type and its stability. If the competent person wants to classify
the soil as Type C, he or she does not need to do any tests. However, tests must be
conducted to determine if the soil can be classified as Type A, B, or solid rock. To do
this, the competent person must use a visual test coupled with one or more manual
tests.
Visual test
In addition to checking the items on the trench inspection form, the competent
person should perform a visual test to evaluate the conditions around the site. In a
visual test, the entire excavation site is observed, including the soil adjacent to the
site and the soil being excavated. The competent person also checks for any signs of
vibration.
During the visual test, the competent person should check for crack-line openings
along the failure zone that would indicate tension cracks; look for existing utilities
that indicate that the soil has been previously disturbed, and, if so, what sort of
backfill was used; and observe the open side of the excavation for indications of
layered geologic structuring.
This person should also look for signs of bulging, boiling, or sloughing, as well as for
signs of surface water seeping from the sides of the excavation or from the water
table.
In addition, the area adjacent to the excavation should be checked for signs of
foundations or other intrusions into the failure zone, and the evaluator should check
for surcharging and the spoil distance from the edge of the excavation.
Manual Tests
Thumb Penetration Test
Attempt to press the thumb firmly into the soil in question. If the thumb penetrates
no further than the length of the nail, it is probably Type B soil. If the thumb
penetrates the full length of the thumb, it is Type C. It should be noted that the
thumb penetration test is the least accurate testing method.
Dry Strength Test
Take a sample of dry soil. If it crumbles freely or with moderate pressure into
individual grains it is considered granular (Type C). Dry soil that falls into clumps that
subsequently break into smaller clumps (and the smaller clumps can be broken only
with difficulty), it is probably clay in combination with gravel, sand, or silt (Type B).
Plasticity or Wet Thread Test
Take a moist sample of the soil. Mold it into a ball and then attempt to roll it into a
thin thread approximately 1/8 inch in diameter by two inches in length. If the soil
sample does not break when held by one end, it may be considered Type B.
Instrumentation Test
A pocket penetrometer, shearvane, or torvane also may be used to determine the
unconfined compression strength of soils.
Protective Systems
Excavation workers are exposed to many hazards, but the chief hazard is cave-ins.
OSHA requires that in all excavations, employees exposed to potential cave-ins be
protected by sloping or benching the sides of the excavation, supporting the sides of
the excavation, or placing a shield between the side of the excavation and the work
area.
Designing a protective system can be complex because of the number of factors
involved: soil classification, depth of cut, water content of soil, changes due to
weather and climate, or other operations in the vicinity. The standard, however,
provides several different methods and approaches (four for sloping and four for
shoring, including the use of shields) for designing protective systems that can be
used to provide the required level of protection against cave-ins.
The employer is free to choose the most practical design approach for any particular
circumstance. Once an approach has been selected, however, the required
performance criteria must be met by that system.
The standard does not require the installation and use of a protective system when an
excavation is either:
1. Made entirely in stable rock
2. Less than five feet deep, and a competent person has examined the ground
and found no indication of a potential cave-in
One method of ensuring the safety and health of workers in an excavation is to slope
the sides to an angle not steeper than one and one-half horizontal to one vertical (34
degrees measured from the horizontal). These slopes must be excavated to form
configurations that are in accordance with those for Type C soil found in Appendix B
of the standard. A slope of this gradation or less is considered safe for any type of
soil.
A second design method, which can be applied for both sloping and shoring, involves
using tabulated data, such as tables and charts, approved by a registered
professional engineer. These data must be in writing and must include sufficient
explanatory information to enable the user to make a selection, including the criteria
for determining the selection and the limits on the use of the data.
At least one copy of the information, including the identity of the registered
professional engineer who approved the data, must be kept at the worksite during
construction of the protective system. Upon completion of the system, the data may
be stored away from the job site, but a copy must be made available, upon request,
to the Assistant Secretary of Labor for OSHA.
Contractors also may use a trench box or shield that is either designed or approved
by a registered professional engineer or is based on tabulated data prepared or
approved by a registered professional engineer. Timber, aluminum, or other suitable
materials may also be used. OSHA standards permit the use of a trench shield (also
known as a welder's hut) as long as the protection it provides is equal to or greater
than the protection that would be provided by the appropriate shoring system.
Spoil Piles
As explained earlier, surcharge is a large weight that affects the strength of the
trench walls. Spoil piles affect cave-ins. OSHA requires the following of placement of
materials and spoil piles.
Temporary spoil must be placed no closer than two feet from the surface edge of the
excavation, measured from the nearest base of the spoil to the cut. This distance
should not be measured from the crown of the spoil deposit. This distance
requirement ensures that loose rock or soil from the temporary spoil will not fall on
employees in the trench. Other soil considerations include:
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Spoil should be placed so that it channels rainwater and other run-off water
away from the excavation.
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Spoil should be placed so that it cannot accidentally run, slide, or fall back into
the excavation.
Permanent spoil should be placed some distance from the excavation.
Protective System Options
OSHA also requires the employer to provide support systems such as shoring,
bracing, or underpinning to ensure the stability of adjacent structures such as
buildings, walls, sidewalks, or pavements. Here are some basic guidelines:
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All excavations or trenches four feet or greater in depth must be appropriately
benched, shored, or sloped according to the procedures and requirements set
forth in OSHA's Excavation standard.
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Excavations or trenches 20 feet deep or greater must have a protective system
designed by a registered professional engineer.
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Excavations under the base of footing of a foundation or wall require a support
system designed by a registered professional engineer.
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Sidewalks and pavement must not be undermined unless a support system or
other method of protection is provided to protect employees from their possible
collapse.
Sloping
Maximum allowable slopes for excavations less than 20 feet based on soil type and
angle to the horizontal are as follows:
Soil Type
Stable Rock
Type A
Type B
Type C
Height/Depth Ratio
Vertical
3/4:1
1:1
1 1/2:1
Slope Angle
90 degrees
53 degrees
45 degrees
34 degrees
A 10-foot-deep trench in Type B soil would have to be sloped to a 45-degree angle, or
sloped 10 feet back in both directions. Total distance across a 10-foot-deep trench
would be 20 feet, plus the width of the bottom of the trench itself. In Type C soil, the
trench would be sloped at a 34-degree angle, or 15 feet back in both directions for at
least 30 feet across, plus the width of the bottom of the trench itself.
Benching
There are two basic types of benching, single and multiple, which can be used in
conjunction with sloping.
In Type B soil, the vertical height of the benches must not exceed 4 feet. Benches
must be below the maximum allowable slope for that soil type. In other words, a 10foot deep trench in Type B soil must be benched back 10 feet in each direction, with
the maximum of a 45-degree angle. Benching is not allowed in Type C soil.
Shoring
Shoring or shielding is used when the location or depth of the cut makes sloping back
to the maximum allowable slope impractical. There are two basic types of shoring:
timber and aluminum hydraulic.
Hydraulic shoring provides a critical safety advantage over timber shoring because
workers do not have to enter the trench to install them. They are also light enough to
be installed by one worker; they are gauge-regulated to ensure even distribution of
pressure along the trench line; and they can be adapted easily to various trench
depths and widths.
All shoring must be installed from the top down and removed from the bottom up.
Hydraulic shoring must be checked at least once per shift for leaking hoses and/or
cylinders, broken connections, cracked nipples, bent bases, and any other damaged
or defective parts.
The top cylinder of hydraulic shoring must be no more than 18 inches below the top
of the excavation.
The bottom of the cylinder must be no higher than four feet from the bottom of the
excavation. (Two feet of trench wall may be exposed beneath the bottom of the rail
or plywood sheeting, if used.)
Three vertical shores, evenly spaced, must be used to form a system.
Wales are installed no more than two feet from the top, no more than four feet from
the bottom, and no more than four feet apart, vertically.
Hydraulic shores must be installed in accordance with Table D - 1.2 and Table D - 1.3
in Type B soil.
Hydraulic shores must be installed with sheeting in accordance with Table D - 1.4 in
Type C soil.
Here are some typical installations of aluminum hydraulic shoring:
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The standard prohibits excavation below the level of the base or footing of any
foundation or retaining wall unless (1) a support system such as underpinning
is provided, (2) the excavation is in stable rock, or (3) a registered professional
engineer determines that the structure is sufficiently removed from the
excavation and that excavation will not pose a hazard to employees.
•
Excavations under sidewalks and pavements are also prohibited unless an
appropriately designed support system is provided or another effective method
is used.
Shielding
Trench boxes are different from shoring because, instead of shoring up or otherwise
supporting the trench face, they are intended primarily to protect workers from caveins and similar incidents.
The excavated area between the outside of the trench box and the face of the trench
should be as small as possible. The space between the trench box and the excavation
side must be backfilled to prevent lateral movement of the box. Shields may not be
subjected to loads exceeding those the system was designed to withstand.
Trench boxes generally are used in open areas, but they also may be used in
combination with sloping and benching.
The box must extend at least 18 inches above the surrounding area if there is sloping
toward the excavation. This can be accomplished by providing a benched area
adjacent to the box.
Any modifications to the shields must be approved by the manufacturer.
Shields may ride two feet above the bottom of an excavation, provided they are
calculated to support the full depth of the excavation and there is no caving under or
behind the shield.
Workers must enter and leave the shield in a protected manner, such as by a ladder
or ramp.
Workers may not remain in the shield while it is being moved.
Other Requirements
OSHA also requires the employer to provide safety management for protective
systems, materials and equipment, and access.
Installation and Removal of Protective Systems
The standard requires the following procedures for the protection of employees when
installing support systems:
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Securely connect members of support systems
Safely install support systems
Never overload members of support systems
Install other structural members to carry loads imposed on the support system
when temporary removal of individual members is necessary
In addition, the standard permits excavation of two feet or less below the bottom of
the members of a support or shield system of a trench if (1) the system is designed
to resist the forces calculated for the full depth of the trench, and (2) there are no
indications, while the trench is open, of a possible cave-in below the bottom of the
support system.
Also, the installation of support systems must be closely coordinated with the
excavation of trenches.
As soon as work is completed, the excavation should be backfilled as the protective
system is dismantled. After the excavation has been cleared, workers should slowly
remove the protective system from the bottom up, taking care to release members
slowly.
Materials and Equipment
The employer is responsible for the safe condition of materials and equipment used
for protective systems. Defective and damaged materials and equipment can result in
the failure of a protective system and cause excavation hazards.
To avoid possible failure of a protective system, the employer must ensure that (1)
materials and equipment are free from damage or defects, (2) manufactured
materials and equipment are used and maintained in a manner consistent with the
recommendations of the manufacturer and in a way that will prevent employee
exposure to hazards, and (3) while in operation, damaged materials and equipment
are examined by a competent person to determine if they are suitable for continued
use. If materials and equipment are not safe for use, they must be removed from
service. These materials cannot be returned to service without the evaluation and
approval of a registered professional engineer.
Access and Egress
Under the standard, the employer must provide safe access to and egress from all
excavations. According to OSHA regulations, when employees are required to be in
trench excavations 4-feet deep or more, adequate means of exit, such as ladders,
steps, ramps, or other safe means of egress must be provided and be within 25 feet
of lateral travel. If structural ramps are used as a means of access or egress, they
must be designed by a competent person (if used for employee access or egress) or
by a competent person qualified in structural design (if used by vehicles). Also,
structural members used for ramps or runways must be uniform in thickness and
joined in a manner to prevent tripping or displacement.
Excavation and trenching work presents serious risks to all workers involved. The
greatest risk, and one of primary concern, is that of a cave-in. Furthermore, when
cave-in accidents occur, they are much more likely to result in worker fatalities than
other excavation-related accidents. Strict compliance, however, with all sections of
the standard will prevent or greatly reduce the risk of cave-ins as well as other
excavation-related accidents.
Topic Summary
Please take a moment to review these key points before you continue with the next
topic.
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OSHA requires that workers in trenches and excavations be protected, and that
safety and health programs address the variety of hazards they face.
A competent person specializing in cave-in hazards requires a great level of
training.
A competent person determines the soil type and its stability by performing a
visual test and one or more of the manual tests.
An excavation protective system is designed by (1) sloping sides to angle, (2)
using tabulated data, or (3) employing a trench box or shield.
Temporary and permanent spoils prevent fallback into the excavation and have
distance requirements.
OSHA has very specific requirements for these protective system options:
benching, sloping, shoring, and shielding.
OSHA requires the employer to provide safety management for protective
systems, materials and equipment, and access during excavation operations.
Topic 3: Controls
OSHA requires employers to take extensive precautions to protect workers. This topic
covers a number of procedures and protective systems designed to protect workers in
or around an excavation. Upon completing this topic, you will be able to:
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Determine the hierarchy of control measures and preplanning strategy
Identify precautions for surface crossing and exposure to vehicles and falling
loads
Explain safety precautions for water accumulation, hazardous atmospheres,
and confined spaces
Manage a safe excavation by following the preplanning specifications
Identify the requirements for a comprehensive excavation training program
and emergency action plan
Reducing the risks associated with construction work is very important. To meet this
goal, there is a hierarchy, or preferred order, of control. These controls are not
mutually exclusive, and there may be occasions when more than one control must be
used to reduce a risk. However, prevention is best served by implementing your
hierarchy or control methodology before you start any construction operation. The
preferred order is presented in the graphic.
By using controls, including protective equipment and proper work practices, you can
operate hand and power tools safely and with confidence.
Administrative and engineering controls can be used to eliminate fall hazards prior to
the beginning of operations. Personal protective equipment (PPE) as a protection
device is your last line of defense and protects you from fall hazards.
Preplanning
Many on-the-job accidents are a direct result of inadequate initial planning. Correcting
mistakes in shoring and/or sloping after work has begun slows down the operation,
adds to the cost, and increases the possibility of an excavation failure. The contractor
should build safety into the pre-bid planning in the same way all other pre-bid factors
are considered.
It is a good idea for contractors to develop safety checklists before preparing a bid to
make certain there is adequate information about the job site and all needed items
are on hand.
These checklists should incorporate elements of the relevant OSHA standards as well
as other information necessary for safe operations.
Before preparing a bid, what specific site conditions should be
considered? :
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Traffic
Proximity of structures and their conditions
Soil
Surface and ground water
The water table
Overhead and underground utilities
Weather
These and other conditions can be determined by job site studies,
observations, test borings for soil type or conditions, and consultations
with local officials and utility companies.
Before any excavation actually begins, the standard requires the employer to
determine the estimated location of utility installations -- sewer, telephone, fuel,
electric, water lines, or any other underground installations -- that may be
encountered during digging. Also, before starting the excavation, the contractor must
contact the utility companies or owners involved and inform them, within established
or customary local response times, of the proposed work. The contractor must also
ask the utility companies or owners to find the exact location of the underground
installations. If they cannot respond within 24 hours (unless the period required by
state or local law is longer), or if they cannot find the exact location of the utility
installations, the contractor may proceed with caution. To find the exact location of
underground installations, workers must use safe and acceptable means. If
underground installations are exposed, OSHA regulations also require that they be
removed, protected, or properly supported.
Preplanning Outline
There are a number of procedures and protective systems designed for preplanning to
protect workers in or around an excavation before the job, on-the job, and during
inspections. Click each plan to learn more about it.
Before Beginning the Job
It is important, before beginning the job, for the contractor to establish and maintain
a safety and health program for the work site that provides adequate policies,
procedures, and practices to protect employees from, and allow them to recognize,
job-related safety and health hazards.
An effective program includes provisions for the systematic identification, evaluation,
and prevention or control of general workplace hazards, specific job hazards, and
potential hazards that may arise from foreseeable conditions.
To be sure safety policies are implemented effectively, there must be cooperation
among supervisors, employee groups (including unions), and individual employees.
Each supervisor must understand the degree of responsibility and authority he or she
holds in a particular area.
It is also important, before beginning work, for employers to provide employees who
are exposed to public vehicular traffic with warning vests or other suitable garments
marked with or made of reflective or high-visibility material and ensure that they
wear them. Workers must also be instructed to remove or neutralize surface
encumbrances that may create a hazard.
In addition, no employee should operate a piece of equipment without first being
trained to handle it properly and fully alerted to its potential hazards.
In the training and in the site safety and health program, it also is important to
incorporate procedures for fast reporting and investigation of incidents.
On-the-Job Evaluation
The standard requires that a competent person inspect, on a daily basis, excavations
and the adjacent areas for possible cave-ins, failures of protective systems and
equipment, hazardous atmospheres, or other hazardous conditions. If these
conditions are encountered, exposed employees must be removed from the
hazardous area until the necessary safety precautions have been taken. Inspections
are also required after natural (e.g., heavy rains) or man-made events (such as
blasting) that may increase the potential for hazards.
Larger and more complex operations should have a full-time safety official who makes
recommendations to improve the implementation of the safety plan. In a smaller
operation, the safety official may be part-time and usually will be a supervisor.
Supervisors are the contractor's representatives on the job. Supervisors should
conduct inspections, investigate accidents, and anticipate hazards. They should
ensure that employees receive on-the-job safety and health training. They should
also review and strengthen overall safety and health precautions to guard against
potential hazards, get the necessary worker cooperation in safety matters, and make
frequent reports to the contractor.
It is important that managers and supervisors set the example for safety at the job
site. It is essential that when visiting the job site, all managers, regardless of status,
wear the prescribed personal protective equipment such as safety shoes, safety
glasses, hard hats, and other necessary gear. Employees must also take an active
role in job safety. The contractor and supervisor should make certain that workers
have been properly trained in the use and fit of the prescribed protective gear and
equipment, that they are wearing and using the equipment correctly, and that they
are using safe work practices.
Inspections
The competent person must conduct inspections at these times:
• Daily and before the start of each shift
• As dictated by the work being done in the trench throughout the work shift
• After every rainstorm
• After other events that could increase hazards, such as snowstorms,
windstorms, thaws, earthquakes, dramatic changes in weather, etc.
• When fissures, tension cracks, sloughing, undercutting, water seepage, bulging
at the bottom, or other similar conditions occur
• When there is a change in the size, location, or placement of the spoil pile
• When there is any indication of change, movement or vibration in adjacent
structures
Inspections must include, at a minimum, review of:
• Surface encumbrances
• Underground installations
• Access and egress
• Exposure to vehicular traffic
• Falling loads
• Mobile equipment warning systems
• Water accumulation
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Adjacent structure
Stability
Loose rock or soil
Fall protection
Hazardous atmospheres
PrePlanning
To prevent cave-ins and additional worker fatalities, OSHA requires that one or more
of the following precautions be taken when working with trenches:
• Utilize a shield or trench box system designed to protect workers in
excavations.
• Shore sides of excavations with timber or other materials to ensure that the
earth does not collapse on workers who must enter them.
• Slope the sides of excavations to reduce the "overburden" (weight and
pressure exerted by large amounts of soil on the sides).
• Secure sides by equivalent means, such as engineer-designed sheeting or
bracing.
Identify the soil characteristics at the work site, and use this information to provide a
safe workplace for construction laborers.
Use prescribed methods of wall retention, piling, cribbing, sloping, shoring, trench
boxing, and sheeting to maintain trench and excavation walls. For each trenching or
excavation situation, you should employ the proper sloping, shoring and bracing
structures and measures designed specifically for the particular situation.
Trench failures often occur in multiples, starting with a movement of soil material
near the bottom of the trench wall. After the failure of the base, the support of the
wall will quickly erode and the wall will collapse. The collapsing soil is extremely
heavy and can weigh one and a half tons per cubic yard, producing a tremendous
crushing force.
Proper design, construction and placement of support structures will allow employees
to work in a safe environment.
Prior to excavation, the location of underground installations (e.g., sewer, telephone,
electrical, fuel, natural gas, water and other lines, and underground tanks) must be
identified and marked.
Excavations more than twenty feet deep must be designed by a registered
professional engineer.
A daily inspection of the excavation, adjacent areas, and protective systems by a
competent person is required. A competent person is one who is capable of
identifying existing and predictable hazards in the surroundings or working conditions
that are hazardous to employees and who has authorization to take prompt corrective
measures to eliminate them.
Workers must be protected from cave-ins by an adequate protective system, except
when excavations are made entirely in stable rock or when the excavations are less
than five feet in depth and examination of the ground by a competent person
provides no indication of a potential cave-in.
When used, sloping must be adequate for the type of soil, as determined by a
competent person.
Trench boxes or shields must be used in accordance with the manufacturer's
recommendations or as designed and approved by a registered professional engineer.
Ramps, runways, ladders, or stairs used as access must be within 25 feet of a work
area if the trench is greater than four feet deep.
A warning system for pedestrian and vehicular traffic must be in place around all
excavations. The warning system must consist of barricades, hand or mechanical
signals, or stop logs and flashing lights at night.
All surface encumbrances that may create a hazard to workers must be removed or
supported.
Adequate protection from hazards associated with water accumulation must be in
place before working in excavations.
Employees exposed to public vehicular traffic must be provided with and wear
reflective warning vests.
Any material or equipment that could fall or roll into an excavation must be placed at
least two feet from the edge of the excavation.
Where workers or equipment are expected to cross over an excavation, walkways
with standard guardrails must be provided.
All employers who work in or around excavations must provide employees with
training in the recognition and avoidance of unsafe conditions and designate a
competent person who must conduct excavation safety inspections and who has the
authority to take corrective action.
Every excavation five feet or greater in depth must be protected from cave-in.
Excavations of less than five feet must also have a protective system or design if
inspection reveals a cave-in hazard.
Exposure Controls
Surface Crossing of Trenches
Surface crossing of trenches should not be made unless absolutely necessary.
However, if necessary, they are only permitted under the following conditions:
Vehicle crossings must be designed by and installed under the supervision of a
registered professional engineer.
Walkways or bridges must:
• Have a minimum clear width of 20 inches
• Be fitted with standard rails
• Extend a minimum of 24 inches past the surface edge of the trench
Exposure to Vehicles
Employees exposed to vehicular traffic must be provided with and required to wear
reflective vests or other suitable garments marked with or made of reflective or highvisibility materials.
Trained flag persons, signs, signals, and barricades must be used when necessary.
Exposure to Falling Loads
• All employees on an excavation site must wear hard hats.
• Employees are not allowed to work under raised loads.
• Employees are not allowed to work under loads being lifted or moved by heavy
equipment used for digging or lifting.
• Employees are required to stand away from equipment that is being loaded or
unloaded to avoid being struck by falling materials or spillage.
• Equipment operators or truck drivers may remain in their equipment during
loading and unloading if the equipment is properly equipped with a cab shield
or adequate canopy.
Environmental Controls
Water Accumulation
Methods for controlling standing water and water accumulation must be provided and
should consist of the following if employees must work in the excavation:
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Use of special support or shield systems approved by a registered professional
engineer
Water removal equipment, such as pumps, used and monitored by a
competent person
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Employees removed from the trench during rainstorms
Trenches carefully inspected by a competent person after each rain and before
employees are permitted to re-enter the trench
The standard prohibits employees from working in excavations where water has
accumulated or is accumulating unless adequate protection has been taken. If water
removal equipment is used to control or prevent water from accumulating, a
competent person must monitor the equipment and operations of the equipment to
ensure proper use.
OSHA standards also require that diversion ditches, dikes, or other suitable means be
used to prevent surface water from entering an excavation and to provide adequate
drainage of the area adjacent to the excavation. Also, a competent person must
inspect excavations subject to runoffs from heavy rains.
Hazardous Atmospheres and Confined Spaces
Under this provision, a competent person must test, before an employee enters,
excavations greater than four feet in depth as well as ones where oxygen deficiency
or a hazardous atmosphere exists or could reasonably be expected to exist. If
hazardous conditions exist, controls such as proper respiratory protection or
ventilation must be provided. Also, controls used to reduce atmospheric contaminants
to acceptable levels must be tested regularly.
Where adverse atmospheric conditions may exist or develop in an excavation, the
employer also must provide and ensure that emergency rescue equipment, (e.g.,
breathing apparatus, a safety harness and line, basket stretcher, etc.) is readily
available. This equipment must be attended when used.
When an employee enters bell-bottom pier holes and similar deep and confined
footing excavations, the employee must wear a harness with a lifeline. The lifeline
must be securely attached to the harness and must be separate from any line used to
handle materials. Also, while the employee wearing the lifeline is in the excavation,
an observer must be present to ensure that the lifeline is working properly and to
maintain communication with the employee.
Training Requirements
Another way to help ensure safe excavation operations is to train the work force
properly in the recognition, identification, evaluation, and control of excavation
hazards.
All employees working on, in, or around an excavation should receive excavation
safety training and must be familiar with the company's safety and health program as
well as those issued by OSHA.
As with all training, the training should be documented, signed by the workers and
the trainer only after comprehension has be verified.
Retraining should occur after an incident and if there are signs of reduced
effectiveness of previous training.
Topic Summary
Please take a moment to review these key points before you continue with the next
topic.
• Determine control measures in this order: engineering, administrative, and
personal protective systems.
• OSHA regulates employees' exposure to surface crossing, vehicles, and falling
loads.
• OSHA has strict standards for controlling water and atmospheric hazards.
• OSHA outlines a comprehensive training program in the recognition,
identification, and evaluation and control of excavation hazards.
Topic 4: Other Issues
This section describes how the employer can prevent other types of common
accidents in the industry.
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Manage an excavation site for fallbacks, equipment mishaps, and slips, trip,
and falls
Identify protection for both underground and above-ground utilities
Maintain good housekeeping to prevent incidents
Demonstrate awareness of reducing public liability when working in or around
excavation
Incidents
There is more to running a safe trenching operation than simply getting in and out of
the excavation alive. For example, falls account for many serious injuries around
excavations. The employer can go a long way to maintain a safe worksite by
controlling what happens on the surface as well as in the trench.
Falling Objects and Material
If excavated material must be placed near the excavation or trench, ensure effective
barricades are in place to prevent fallback. Heavy tarpaulins, sheeted barricades and
built-up board barricades can help keep excavated material out of work areas.
Barriers can help keep tools and workers from falling onto other workers in the
excavation or trench. If the trench or excavation must stay open for a long time,
barricades, fences, and so forth are necessary. Guard the site at night with flashing
lights or security fences. Keep workers out of the operating radius of backhoes and
other equipment.
Equipment Mishaps
To prevent heavy mobile equipment accidents:
• Maintain the safety features, such as rollover protective structures
• Provide systematic inspection, maintenance and repair programs
• Make sure operators and repair personnel are competent
• Require workers to use three-point contacts and avoid jumping when getting
on or off equipment
• Do not allow passengers to ride outside of equipment cabs
Equipment operations should be planned and managed carefully. Workers can easily
be struck by mobile equipment in construction areas, particularly when machines are
backing up. Backing alarms are required on all mobile equipment in areas where
workers are at risk of being struck.
In crowded work areas, have a signaler direct traffic and warn workers of moving
equipment. Each signaler should wear a high-visibility vest when directing traffic.
A standard set of signals should always be used, and the signaler should stay in the
view of drivers at all times.
Workers should be warned to keep away from excavators, backhoes, and similar
equipment. When appropriate, danger zones around this equipment should be
barricaded or roped off to keep workers out. Operators should be informed before any
worker enters. Operators should keep workers in the danger zone in sight at all
times. Equipment should not be operated while workers are present.
Slips, Trips, and Falls
Make sure that ladders extend at least three feet above the trench wall. When using a
ladder, workers should be instructed to hold both side rails and have one foot on a
rung at all times (three-point contact). Use ropes to lower materials and tools into the
trench. Do not carry them up and down ladders or throw them into or out of the
trench.
Where ladders rest on the edges of cut pavement, make sure the pavement's
undersurface does not crumble and cause workers on the ladders to fall or be struck
by debris.
Make sure fences and barriers at the trench surface are secure and will protect
workers when needed. Remember to keep fences and barriers far enough away from
the edge of the trench to prevent workers or bystanders from slipping or falling into
the opening.
Provide fall protection to workers working on the edge of the trench.
Warning Systems for Mobile Equipment
The following steps should be taken to prevent vehicles from accidentally falling into
the trench:
• Barricades must be installed where necessary.
• Hand or mechanical signals must be used as required.
• Trenches left open overnight must be fenced and barricaded.
In addition to cave-in hazards and secondary hazards related to cave-ins, there are
other hazards from which workers must be protected during excavation-related work.
These hazards include exposure to falls, falling loads, and mobile equipment. To
protect employees from these hazards, OSHA requires the employer to take the
following precautions:
• Keep materials or equipment that might fall or roll into an excavation at least
two feet from the edge of excavations, or have retaining devices, or both.
• Provide warning systems such as mobile equipment, barricades, hand or
mechanical signals, or stop logs to alert operators of the edge of an excavation.
If possible, keep the grade away from the excavation.
• Provide scaling to remove loose rock or soil or install protective barricades and
other equivalent protection to protect employees against falling rock, soil, or
materials.
• Prohibit employees from working on faces of sloped or benched excavations at
levels above other employees unless employees at lower levels are adequately
protected from the hazard of falling, rolling, or sliding material or equipment.
• Prohibit employees under loads that are handled by lifting or digging
equipment. To avoid being struck by any spillage or falling materials, require
employees to stand away from vehicles being loaded or unloaded. If cabs of
vehicles provide adequate protection from falling loads during loading and
unloading operations, the operators may remain in them.
Utilities
Take steps to protect both underground and above-ground utilities, which include but
are not limited to water, sewer, gas, and/or overhead power lines by themselves or in
multiple configurations.
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Contact the utility owner's one call.
Aggressively research the area to be excavated.
Develop a site map.
Utilize a recognized marking system.
Require hand digging.
Keep and maintain proper distance.
Require an excavation permit.
Check for overhead services, such as power and phone lines. If overhead lines could
be hazardous, consult the owner of the service.
Color Code for Marking Underground Utility Lines
Public Liability
The public has always been intrigued with construction projects, and an excavation or
trench is no exception; in fact, it may create greater interest among the public. With
greater interest also comes greater risk. Contractors and contractor employees must
always be aware to protect excavations and trenches for each other but also to
reduce or eliminate the risk to the public. Here is a list of precautions:
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Notify the affected public
Plan excavation and backfill timing
Utilize sufficient barricading, fencing, or other protection devices
Establish clear traffic routes for both vehicles and pedestrians
Kids of all ages love excavations. It is hard for them to resist playing around
construction sites and exploring trenches and excavations. Adventurous youngsters
also enjoy digging holes and tunnels for hideouts and clubhouses.
Unfortunately, these are dangerous games. Construction areas present a number of
hazards, including the possibility of an excavation collapsing and burying a child. As
for the pits and tunnels youngsters like to dig, these are also dangerous.
Parents must be alert to these activities and put a stop to them. Before the
neighborhood clubhouse starts turning into an underground village, it is time to step
in.
Without engineering preparation and proper shoring, excavations, pits, or tunnels dug
by children can become death traps. Children and all passersby must stay well away
from excavations in the neighborhood, along the roads and in the workplace. Know
where your kids are and don't let them play in these danger zones.
The hazards are not confined to children. Not long ago an adult was killed at a beach
when the large pit he had dug collapsed on him.
Housekeeping
Housekeeping is a very important part of your job. It improves the overall appearance
of your work area. Here are some reasons to keep your work area clean:
1. To reduce trip and fall hazards
2. To increase production (You won't have to waste time looking for a misplaced
tool. You will always know where your tools are when you put them where they
belong after you use them.)
3. To reduce a potential fire hazard by removing unneeded combustibles from the
work area
OSHA has the requirements for housekeeping:
• Form and scrap lumber with protruding nails, and all other debris, must be kept
cleared from work areas, passageways, and stairs in and around buildings or
other structures.
• Combustible scrap and debris must be removed at regular intervals during the
course of construction.
• Containers must be provided for the collection and separation of waste, trash,
oily and used rags, and other refuse.
• Containers used for garbage and other oily, flammable, or hazardous wastes,
such as caustics, acids, harmful dusts, etc., must be equipped with covers.
• Garbage and other waste must be disposed of at frequent and regular
intervals.
Tips to Maintain a Clean Work Area
• Plan the job. Make a list of the needed tools/materials. This will help to
minimize unnecessary clutter around your work area.
• Develop a routine for cleaning up at the end of the shift or periodically during
the shift.
• Do not allow employees to eat, drink, or smoke in the work area, not only
because of litter problems but also because of hygiene concerns.
If your housekeeping habits are poor, the result may be employee injuries or even
death, citations by OSHA (or another regulatory agency), and even difficulty in
securing future work. How can such a "minor" issue have such serious consequences?
Here are some results of poor housekeeping practices:
• Injuries when employees trip, fall, strike, or are struck by out-of-place objects
• Injuries from using improper tools because the correct tool can't be found
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Lowered production because of the time spent maneuvering over and around
someone else's mess and time spent looking for proper tools and materials
Time spent investigating and reporting incidents tha
Topic Summary
Take a moment to review these major points before you continue with the next topic.
• Contractors and contractor employees must always be aware to protect
excavation and trenches to reduce the risk of public liability.
• Consult the owners of water, sewer, gas, and power lines if utilities could be
hazardous.
• Protect yourself from falling objects, equipment mishaps, and slips, trips, and
falls by following OSHA's guidelines.
Lesson Summary
This lesson contained information and instruction about excavation. By completing
this lesson, you should have the knowledge to discuss the following topics. Take a
moment to see if you can do the following:
• Identify and minimize excavation hazards
• Outline OSHA's requirements and support systems for in trenches and
excavation
• Manage controls and other procedures and protective systems designed to
protect workers in or around an excavation
• Prevent other types of common surface and trench incidents
• Plan and train the workforce in the recognition, identification, evaluation, and
control of excavation hazards
Concrete and Masonry
Introduction
Concrete and masonry construction is part of everyday life worldwide, from small
projects to large ones, from general building to residential and highway construction,
and from bricks to blocks.
Unfortunately, OSHA recorded many injuries and fatalities that occurred during
concrete and masonry work.
Case Report:
An employee was struck by a collapsed concrete wall when he was checking
the bracing on the 20 feet high by 8 inch wide by 45 feet long concrete block
masonry wall. The top 8 feet section of the wall was blown over during a
windstorm. He died of a head injury.
To prevent the injuries, you must be fully aware of the types of hazards as well as the
safety precautions when doing concrete and masonry work.
OSHA has established requirements to help protect workers from the hazards
associated with concrete and masonry work at construction, demolition, alteration, or
repair worksites.
Lesson Overview
This lesson reviews OSHA requirements for concrete and masonry operations.
Upon completing this lesson, you will be able to:
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Explain what concrete is and describe OSHA general provisions for concrete
and masonry
Describe OSHA requirements for cast-in-place concrete
List the hazards associated with concrete and masonry use and discuss the
various control methods
Explain why silica is hazardous and list good work practices for reducing silica
exposure and preventing silicosis
Why Learn This Lesson?
This lesson will help you learn more about the hazards associated with concrete and
masonry work. It will offer you an opportunity to better understand the control
methods available to reduce or eliminate these hazards.
Concrete and masonry work is a specific area within the construction practice. The
better you understand the hazards and controls associated with this work, the more
likely you are to go home well at the end of the work day.
Topic 1: General Information
This topic reviews the general safety provisions for concrete and masonry. Upon
completing this topic, you should be able to:
•
Describe OSHA general safety requirements for concrete and masonry in these
areas: construction loads, reinforcing steel, post-tensioning operations,
concrete buckets, working under loads, personal protective equipment, and
equipment and tools
OSHA General Provisions
OSHA has established some general requirements for concrete and masonry in the
following areas.
Construction loads
Construction loads must not be placed on a concrete structure or portion of a
concrete structure unless it has been determined by a qualified person (in structural
design) that the structure or portion of the structure is capable of supporting the
intended loads.
Reinforcing steel
If there is any protruding reinforcing steel that workers could either fall onto or into,
it must be guarded to eliminate the hazard of impalement.
Post-tensioning operations
Employees (except those essential to the post-tensioning operations) are not
permitted to be behind the jack during tensioning operations.
Signs and barriers must be erected to limit employee access to the post-tensioning
area during tensioning operations.
Concrete buckets
Employees must not be permitted to ride concrete buckets during work operations.
What's an employer's responsibility?
Employers must comply with OSHA requirements to protect construction
workers from incidents and injuries resulting from:
o The premature removal of formwork
o The failure to brace masonry walls
o The failure to support precast panels
o The inadvertent operation of equipment
o The failure to guard reinforcing steel
Working under loads
Employees are not permitted to work under concrete buckets while the buckets are
being elevated or lowered into position.
As much as is practical on the site, elevated concrete buckets must be routed so that
no employee or the fewest employees possible are exposed to the hazards associated
with falling concrete buckets.
Personal protective equipment
Employees are not permitted to apply a cement, sand, and water mixture through a
pneumatic hose unless they are wearing protective head and face equipment.
Employees are not permitted to place or tie reinforcing steel more than six feet above
any adjacent working surfaces unless they are protected by the use of fall protection
meeting OSHA standards.
Equipment and tools
The standards also include requirements for the following equipment and operations:
• Bulk cement storage
• Concrete mixers
• Power concrete trowels
• Concrete buggies
• Concrete pumping systems
• Concrete buckets
• Tremies
• Bull floats
• Masonry saws
• Lockout/tag out procedures
Topic Summary
Please take a moment to review these major points before you continue with the next
topic.
• Construction loads must not be placed on a concrete structure or portion of a
concrete structure unless it has been determined by a qualified person (in
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structural design) that the structure or portion of the structure is capable of
supporting the intended loads.
If there is any protruding reinforcing steel that workers could either fall onto or
into, it must be guarded to eliminate the hazard of impalement.
Employees (except those essential to the post-tensioning operations) are not
permitted to be behind the jack during tensioning operations.
Employees must not be permitted to ride concrete buckets during work
operations.
Employees are not permitted to work under concrete buckets while the buckets
are being elevated or lowered into position.
Employees are not permitted to apply a cement, sand, and water mixture
through a pneumatic hose unless they are wearing protective head and face
equipment.
Topic 2: Safety Requirements for Cast-In-Place Concrete
This topic addresses the safety requirements for cast-in-place concrete. Upon
completing this topic, you should be able to:
• Describe safety requirements for shoring and reshoring
• Describe safety requirements for vertical slip forms
• Describe safety requirements for removal of formwork
• Describe safety requirements for precast concrete
• Describe safety requirements for lift-slab operations
• Describe safety requirements for masonry construction
General Requirements
General Requirements for Formwork
Formwork must be designed, fabricated, erected, supported, braced, and maintained
so that it will be capable of supporting without failure all vertical and lateral loads that
might be applied to the formwork.
Drawings or Plans
Drawings and plans, including all revisions for the jack layout, formwork (including
shoring equipment), and working decks and scaffolds must be available at the job
site.
Shoring and Reshoring
All shoring equipment (including equipment used in reshoring operations) must be
inspected prior to erection to determine that the equipment meets the requirements
specified in the formwork drawings.
Damaged shoring equipment must not be used for shoring. Erected shoring
equipment must be inspected immediately prior to, during, and immediately after
concrete placement. Shoring equipment that is found to be damaged or weakened
after erection must be reinforced immediately.
If single-post shores are used one on top of another (tiered), then additional shoring
requirements must be met.
Adjustment of single-post shores to raise formwork must not be made after the
placement of concrete.
Reshoring must be erected, as the original forms and shores are removed, whenever
the concrete is required to support loads in excess of its capacity.
What are the additional requirements for single-post shores that are used on
top of another shore?
If single-post shores are used one on top of another (tiered), then additional
shoring requirements must be met. The shores must be as follows:
• Designed by a qualified designer and the erected shoring inspected by an
engineer qualified in structural design
• Vertically aligned
• Spliced to prevent misalignment
• Adequately braced in two mutually perpendicular directions at the splice
level (Each tier also must be diagonally braced in the same two
directions.)
Vertical Slip Forms
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The steel rods or pipes on which jacks climb or by which the forms are lifted
must be designed specifically for that purpose and adequately braced where
not encased in concrete.
Forms must be designed to prevent excessive distortion of the structure during
the jacking operation.
Jacks and vertical supports must be positioned in such a manner that the loads
do not exceed the rated capacity of the jacks.
The jacks or other lifting devices must be provided with mechanical dogs or
other automatic holding devices to support the slip forms whenever failure of
the power supply or lifting mechanisms occurs.
The form structure must be maintained within all design tolerances specified
for plumpness during the jacking operation.
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The predetermined safe rate of a lift must not be exceeded.
All vertical slip forms must be provided with scaffolds or work platforms where
employees are required to work or pass.
Removal of Formwork
Forms and shores (except those used for slabs on grade and slip forms) must not be
removed until the employer determines that the concrete has gained sufficient
strength to support its weight and superimposed loads. Such determination must be
based on compliance with one of the following two requirements:
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The plans and specifications stipulate conditions for removal of forms and
shores, and such conditions have been followed.
The concrete has been properly tested with an appropriate ASTM standard test
method indicating that the concrete has gained sufficient strength to support
its weight and superimposed loads.
Reshoring must not be removed until the concrete being supported has attained
adequate strength to support its weight and all loads in place upon it.
Precast Concrete
Precast concrete wall units, structural framing, and tilt-up wall panels must be
adequately supported to prevent overturning and collapse until permanent
connections are completed.
Lifting inserts that are embedded or otherwise attached to tilt-up wall panels must be
capable of supporting at least two times the maximum intended load applied or
transmitted to them; lifting inserts for other precast members must be capable of
supporting four times the load.
Only essential employees are permitted near precast concrete that is being lifted or
tilted into position.
Lift-Slab Operations
Lift-slab operations must be designed and planned by a registered professional
engineer who has experience in lift-slab construction. Such plans and designs must be
implemented by the employer and must include detailed instructions and sketches
indicating the prescribed method of erection. The plans and designs also must include
provisions for ensuring lateral stability of the building/structure during construction.
Jacking equipment must be capable of supporting at least two and a half times the
load. For the purpose of this provision, jacking equipment includes any load-bearing
component that is used to carry out the lifting operation(s). Such equipment includes,
but is not limited to, the following: threaded rods, lifting attachments, lifting nuts,
hook-up collars, T-caps, shearheads, columns, and footings.
No employee, except those essential to the jacking operation, should be permitted in
the building/structure while any jacking operation is taking place unless the
building/structure has been reinforced sufficiently to ensure its integrity during
erection. The phrase "reinforced sufficiently to ensure its integrity" used in this
paragraph means that a registered professional engineer, independent of the
engineer who designed and planned the lifting operation, has determined from the
plans that if there is a loss of support at any jack location, that loss will be confined to
that location and the structure as a whole will remain stable.
Under no circumstances must any employee who is not essential to the jacking
operation be permitted beneath a slab while it is being lifted.
Masonry Construction
Whenever a masonry wall is being constructed, employers must establish a limited
access zone prior to the start of construction. The limited access zone must be:
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Equal to the height of the wall to be constructed plus four feet, and must run
the entire length of the wall
On the side of the wall that will be without scaffolding
Restricted to entry only by employees actively engaged in constructing the wall
Kept in place until the wall is adequately supported to prevent overturning and
collapse, unless the height of wall is more than eight feet and unsupported. In
that case, it must be braced. The bracing must remain in place until permanent
supporting elements of the structure are in place.
Constructing concrete and masonry walls is especially dangerous because of the
tremendous loads that need to be supported. There are risks of major accidents, and
even death, when jacks or lifting equipment are used to position slabs and walls, or
when shoring is required until structures can support themselves.
Topic Summary
Please take a moment to review these key points before you continue with the next
topic.
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Formwork must be designed, fabricated, erected, supported, braced, and
maintained so that it will be capable of supporting without failure all vertical
and lateral loads that might be applied to the formwork.
Drawings and plans, including all revisions for the jack layout, formwork
(including shoring equipment), and working decks and scaffolds must be
available at the job site.
All shoring equipment (including equipment used in reshoring operations) must
be inspected prior to erection to determine that the equipment meets the
requirements specified in the formwork drawings.
Reshoring must be erected, as the original forms and shores are removed,
whenever the concrete is required to support loads in excess of its capacity.
All vertical slip forms must be provided with scaffolds or work platforms where
employees are required to work or pass.
Forms and shores (except those used for slabs on grade and slip forms) must
not be removed until the employer determines that the concrete has gained
sufficient strength to support its weight and superimposed loads.
Only essential employees are permitted near precast concrete that is being
lifted or tilted into position.
Lift-slab operations must be designed and planned by a registered professional
engineer who has experience in lift-slab construction.
No employee, except those essential to the jacking operation, should be
permitted in the building/structure while any jacking operation is taking place
unless the building/structure has been reinforced sufficiently to ensure its
integrity during erection.
Whenever a masonry wall is being constructed, employers must establish a
limited access zone prior to the start of construction.
Topic 3: Hazards and Controls
This topic examines the health hazards associated with concrete and masonry and the
controls that should be implemented to protect workers. Upon completing this topic,
you should be able to:
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List the hazards associated with concrete and masonry
Describe the engineer controls for concrete and masonry hazards
Describe the administrative controls for concrete and masonry hazards
Describe the PPE controls for concrete and masonry hazards
Hazards
Common hazards associated with concrete and masonry include:
• Chemicals
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Falls
Noise
Lifting
Slips
Crushing
Struck-by
Electrical
The following case reports of accidents investigated by OSHA illustrate how seemingly
innocent workplace activities can have deadly consequences.
Case Reports
• In inclement weather, a 34-year-old worker was positioning vertical and
horizontal rebar for a cap tie beam to be poured the next day. Strong, gusting
winds caused a free-standing masonry block wall to collapse, fatally injuring
the employee. Bracing and shoring could have prevented the collapse or
lessened the impact.
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Three concrete finishers were working in the basement of a home under
construction, placing cement for the basement floor. A cement truck was
parked two feet away from the west wall, unloading six yards of cement into
the basement. The two-foot area around the foundation had been backfilled
about an hour and a half before the cement finishers began their work. One of
the employees directed the cement chute, starting at the northwest corner of
the building. By the time he got to the southwest corner, the truck was empty.
Suddenly, the west wall collapsed, crushing him to death. The other two
employees were able to escape with only minor injuries.
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An employee and two co-workers were erecting 8'x35' pre-stressed concrete
wall panels. They would set the panel, then anchor the bottom, and then
unhook the panels from the crane. Three panels had already been set, and the
victim was atop the panels waiting for the welder to finish anchoring the
bottom of the third panel. The panels began to tip outward and slowly fall, and
the victim fell or jumped, landing in the path of the falling panels. He died from
the head injuries he sustained.
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The victim was a member of a crew that was erecting tilt-up wall panels around
the perimeter of the slab floor of a one-story warehouse. The last three wall
slabs were being hoisted into place with two 12-foot nylon web slings in a
basket hitch. While the second panel was suspended in preparation for being
set, it tilted in the sling and slid slightly, cutting through one sling and partially
through the other. The erection crew scattered as it dropped, but the victim
stopped momentarily to look back as he fled the building. Just then, the upper
edge of a previously set panel, which had been dislodged by the falling panel,
fell on him. He was crushed and killed.
Work Practices
The following are good work practices for the use of concrete and masonry:
• Do not place construction loads on a concrete structure until a qualified person
indicates that it can support the load.
• Adequately shore or brace structures until permanent supporting elements are
in place or concrete has been tested to assure sufficient strength.
• Allow only those who are essential to and actively engaged in construction or
lifting operations to enter the work area.
• Take measures to prevent unrolled wire mesh from recoiling, such as securing
each end or turning the roll over.
• Do not load lifting devices beyond their capacities.
• Use automatic holding devices to support forms in case a lifting mechanism
fails.
PPE
Personal protective equipment must be provided, used, and maintained in a sanitary
and reliable condition. PPE refers to many different protective devices, but OSHA PPE
standard specifically talks about eye, face, head, and extremity protection.
Even though it is not required by this standard, a hazard assessment of all work areas
should be conducted so that proper protective equipment can be selected. When
choosing PPE, you should consider such hazards as heat, impact, chemicals,
compression, electrical, light/radiation, punctures, and dust.
Rebar Protection
Exposure to impalement is always a consideration when employees are working
above rebar or other sharp protrusions. The critical element when evaluating any job
activity is the recognition or identification of impalement hazards and the exposure to
employees. As you know, construction activities constantly change and contractors
must remain aware of and provide protection from or alternate work practices to
eliminate impalement hazards.
When employees are working at any height above exposed rebar, fall
protection/prevention is the first line of defense against impalement.
Fall protection/prevention also is applicable when the rebar is below grade, e.g.,
footings or other excavations, where a fall into a trench would present an impalement
hazard.
When work is at grade, impalement exposure is dependent upon numerous situations
and conditions such as proximity of rebar to the worker, height of rebar, and so on.
Rebar caps/covers are appropriate to prevent cuts, abrasions, or other minor injuries
when working at grade and there is no impalement hazard.
Topic Summary
Please take a moment to review these key points before you continue with the next
topic.
• Common hazards associated with concrete and masonry include: chemicals,
falls, noise, ergonomics, slips, crushing, struck-by, and electrical.
• Remember these good work practices to prevent concrete and masonry
hazards:
o Do not place construction loads on a concrete structure until a qualified
person indicates that it can support the load.
o Adequately shore or brace structures until permanent supporting
elements are in place or concrete has been tested to assure sufficient
strength.
o Allow only those who are essential to and actively engaged in
construction or lifting operations to enter the work area.
o Take measures to prevent unrolled wire mesh from recoiling, such as
securing each end or turning the roll over.
o Do not load lifting devices beyond their capacities.
o Use automatic holding devices to support forms in case a lifting
mechanism fails.
• Protective equipment must be provided and used when working with or around
concrete and masonry.
Topic 4: Silica
This topic reviews the common situations where construction workers are likely to be
exposed to silica hazards, the deadly results of silicosis, and how to prevent it. Upon
completing this topic, you should be able to:
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Identify common situations where you could be exposed to silica
List good work practices for reducing silica exposure and preventing silicosis
Exposure to Silica
In construction, workers can easily be exposed to silica when using rock containing
silica or concrete and masonry products that contain silica sand. Exposure to
crystalline silica can occur in the following construction activities:
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Chipping, hammering, and drilling in rock or concrete or brick
Crushing, loading, hauling, and dumping of rock and concrete
Abrasive blasting using silica sand or from the materials being blasted
(concrete)
Sawing, hammering, drilling, grinding, and/or chipping on masonry or concrete
Demolition of brick, concrete, or masonry
Dry-sweeping concrete, sand, or rock dust
Trenching and excavation
Tile and grout work
Remember that even materials containing small amounts of crystalline silica may be
hazardous if they are used in ways that produce high dust concentrations.
Silicosis
Exposure to respirable crystalline silica dust during construction activities can cause
silicosis - a scarring and hardening of lung tissue. The disease can be progressively
debilitating and fatal.
According to OSHA Enforcement Information for Construction, 11 percent of the
workplace deaths due to silicosis, where silicosis was identified on the death
certificates, were in the construction industry.
Of all OSHA samples collected in construction for crystalline silica, 26 percent exceed
the OSHA PEL (Permissible Exposure Level).
Recent case examples in construction:
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A 39-year-old sandblaster diagnosed with silicosis and tuberculosis after 22
years of abrasive blasting. He began noticing gradual shortness of breath,
wheezing, and chest discomfort. Lung tissue samples showed extensive fibrosis
(silicosis).
A 49-year-old man diagnosed with silicosis, emphysema, and asthma after 21
years of work as a tile installer where he was exposed to dust from cutting,
drilling, and working with grout. He was a nonsmoker.
A brick mason diagnosed with silicosis, emphysema, and lung cancer at age 70
after working 41 years laying brick. He was a nonsmoker.
A 47-year-old man diagnosed with severe silicosis after working 22 years as a
rock driller
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A 69-year-old male died of silicosis after working two years as a tunnel
construction worker. Previous to that he had been a nurse. He did not wear a
respirator, nor did he know of the need to wear one.
A 55-year-old man was diagnosed with simple silicosis after working 30 years
as a building renovation mason. A lung biopsy revealed silica nodules, but he
was still working. He periodically was involved with sandblasting and using a
masonry saw.
A Texas physician reported on three individuals with silicosis who sandblasted
pipes in the oil fields. One of the workers, a 34-year-old male later died from
silicosis. A later investigation found 10 workers with silicosis who did
construction sandblasting. Nine of the workers worked for the same company.
Seven were under the age of 30.
At a New England site where the employer was using Black Beauty to blast
concrete, overexposure to crystalline silica was 1.4 times the PEL. Employees
chipping on concrete had levels greater than 6 times the PEL. (The silica in the
samples was 19-21 percent.) It also was found that employer was aware of the
hazards of silica, had not provided information and training, and that workers
with beards wore unapproved respirators. A consultant also found that workers
wearing abrasive blasting hoods were overexposed inside the blast helmets.
On another construction site, workers doing abrasive blasting were exposed to
up to 90 percent silica and were found at 80 times the PEL.
Inspection of an employer in Cleveland was initiated from an employee
complaint. . The worker has silicosis and only recently stopped working. OSHA
issued a citation of willful violations for silica used in abrasive blasting to that
employer.
Prevent Silicosis
Employers and workers can take practical steps to reduce exposures and lower risks.
NIOSH recommends the following measures to reduce exposures to respirable
crystalline silica in the workplace and to prevent silicosis and deaths among
construction workers:
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Recognize when silica dust may be generated and plan ahead to eliminate or
control the dust at the source. Awareness and planning are the keys to
preventing silicosis.
Do not use silica sand or other substances containing more than one percent
crystalline silica as abrasive blasting materials. Substitute less hazardous
materials.
Use engineering controls and containment methods such as blast-cleaning
machines and cabinets, wet drilling, or wet sawing of silica-containing materials
to control the hazard and protect adjacent workers from exposure.
Routinely maintain dust control systems to keep them in good working order.
Wear disposable or washable protective clothes at the worksite.
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Shower (if possible) and change into clean clothes before leaving the worksite
to prevent contamination of cars, homes, and other work areas.
Conduct air monitoring to measure worker exposures and ensure that controls
are providing adequate protection for workers.
Use adequate respiratory protection when source controls cannot keep silica
exposures below the NIOSH PEL.
Provide periodic medical examinations for all workers who may be exposed to
respirable crystalline silica.
Post warning signs to mark the boundaries of work areas contaminated with
respirable crystalline silica.
Provide workers with training that includes information about health effects,
work practices, and protective equipment for respirable crystalline silica.
Key point: The key to silicosis prevention is keeping silica dust out of the air. OSHA
requires dust to be controlled whenever possible.
Topic Summary
Please take a moment to review these key points before you continue with the next
topic.
• In construction, workers can be easily exposed to silica when using rock
containing silica or concrete and masonry products containing silica sand. Even
materials containing small amounts of crystalline silica may be hazardous if
they are used in ways that produce high dust concentrations.
• Exposure to respirable crystalline silica dust during construction activities can
cause silicosis - a scarring and hardening of lung tissue. The disease can be
progressively debilitating and fatal.
• Employers and workers can take practical steps to reduce exposures and lower
risks.
• Recognize when silica dust may be generated and plan ahead to eliminate or
control the dust at the source. Awareness and planning are keys to preventing
silicosis.
Lesson Summary
This lesson contains information and instruction about concrete and masonry. By
completing this lesson, you should have the knowledge to discuss the following
topics. Take a moment to see if you can do the following:
• Explain what concrete is and describe OSHA general provisions for concrete
and masonry
• Describe OSHA requirements for cast-in-place concrete
• List the hazards associated with concrete and masonry use and discuss the
various control methods
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Explain why silica is hazardous and list good work practices for reducing silica
exposure and preventing silicosis
Steel Erection
Introduction
Incidents during steel erection continue to cause injuries and fatalities at
construction sites. Fatalities associated with steel erection generally have been
caused by the following hazards:
• Collapses while landing or placing a load as a result of placing loads on
unsecured or unbridged joists
• Collapses while connecting joists or trusses as a result of prematurely
disconnecting the crane before the piece was secure
• Workers struck by objects during miscellaneous activities as a result of
walking or working under a load
• Improper use or failure of fall protection as a result of workers' failure to
use available fall protection systems
• Unsecured or unstable decking, such as stepping onto or working on
unsecured decking that slipped out of place when fall protection was not
provided or used
• Other falls during decking activities, such as stepping off the metal
decking onto insulation (and then falling to the ground) during roofing
operations where fall protection was not provided or used
• Walking/standing on the beam/joist (i.e., moving point-to-point), such
as slips or falls where fall protection was not provided or used
Lesson Overview
In this lesson, you will learn about common steel erection activities and
OSHA's requirements for those activities. You also will learn more about the
open web steel joists and the systems-engineered metal buildings. Finally, you
will have a chance to review fall protection for steel erection activities.
Upon completing this lesson, you will be able to:
• List common steel erection activities and explain the importance of
preplanning in steel erection
• Describe OSHA's requirements for these common steel erection
activities: rigging and hoisting, structural steel assembly, column
stability, and beams and columns
• Describe OSHA requirements for open web steel joints
• Describe OSHA requirements for systems-engineered metal buildings
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Summarize the fall protection requirements in steel erection including
requirements for connectors and CWZ
Why Learn This Lesson?
Every year, an average of 35 workers die during steel erection activities and
2,300 more suffer lost workdays due to injuries. This lesson will provide the
learner with the proper procedures and requirements to help prevent fatalities
and injuries.
This lesson addresses the hazards that have been identified as the major
causes of injuries and fatalities in the steel erection industry.
Topic 1: Steel Erection and Preplanning
This topic reviews where steel erection may occur, common steel erection
activity, and the importance of preplanning in steel erection. Upon completing
this topic, you should be able to:
• List steel erection activities that OSHA covers
• Describe what needs to be considered when planning steel erection
Where Steel Erection May Occur
Some examples of structures where steel erection may occur include:
• Single and multi-story buildings
• Systems-engineered metal buildings
• Lift slab/tilt-up structures
• Energy exploration structures
• Energy production, transfer and storage structures and facilities
• Auditoriums
• Malls
• Amphitheaters
• Stadiums
• Power plants
• Mills
• Chemical process structures
• Bridges
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Trestles
Overpasses
Monorails
Metal roofs
Industrial structures
Water process and water containment structures
Amusement park structures and rides
Artistic and monumental structures
This list is just a sample of the many types of projects where steel erection
operations are in place.
Steel Erection Activities
We just looked at the types of job sites where steel erection occurs, but what
activities on these sites does OSHA cover with its safety requirements?
These are the steel erection activities that OSHA covers:
• Hoisting, laying out, placing, connecting, welding, burning, guying,
bracing, bolting, plumbing, and rigging structural steel, steel joists, and
metal buildings
• Installing metal decking, curtain walls, window walls, siding systems,
miscellaneous metals, ornamental iron, and similar materials
• Moving point-to-point while performing these activities
Preplanning
OSHA has recognized that under current practices in the industry, erection
decisions are often made in the field when the steel arrives. OSHA believes
that preplanning and coordination are not occurring to the extent they should
be and has, therefore, established certain criteria.
Site Layout Preplanning
Prior to engaging in any steel erection activities there are certain requirements
that the controlling contractor must meet in regard to the layout of the site.
These requirements include making sure the following are provided and
maintained:
• Adequate access roads into and through the site for the safe delivery
and movement of derricks, cranes, trucks, other necessary equipment,
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and the material to be erected and means and methods for pedestrian
and vehicular control. Exception: This requirement does not apply to
roads outside the construction site.
A firm, properly graded, drained area, readily accessible to the work and
with adequate space for the safe storage of materials and the safe
operation of the erector's equipment
Preplanning of Overhead Hoisting Operations
All hoisting operations that are to take place during steel erection operations
must be planned in advance and be in compliance with the OSHA requirements
for hoisting.
Training Requirements
Employers must provide adequate training on steel erection to address the
hazards presented in this lesson.
Fall hazard training
The employer must provide a training program for all employees exposed to
fall hazards. The program must include training and instruction in the following
areas:
• The recognition and identification of fall hazards in the work area
• The use and operation of guardrail systems (including perimeter safety
cable systems), personal fall arrest systems, positioning device systems,
fall restraint systems, safety net systems, and other protection to be
used
• The correct procedures for erecting, maintaining, disassembling, and
inspecting the fall protection systems to be used
• The procedures to be followed to prevent falls to lower levels and
through or into holes and openings in walking/working surfaces and
walls
• The fall protection requirements of this subpart
Special training programs
In addition, the employer must provide special training to employees engaged
in the following activities:
• Multiple lift rigging procedure: The employer must ensure that each
employee who performs multiple lift rigging has been provided training
in the following two areas:
o The nature of the hazards associated with multiple lifts
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o The proper procedures and equipment to perform multiple lifts
Connector procedures: The employer must ensure that each connector
has been provided training in the following two areas:
o The nature of the hazards associated with connecting
o The establishment, access, and proper connecting techniques and
work practices
Controlled Decking Zone (CDZ) Procedures: Where CDZs are being used,
the employer must ensure that each employee has been provided
training in the following two areas:
o The nature of the hazards associated with work within a controlled
decking zone
o The establishment, access, and proper installation techniques and
work practices
Topic Summary
Please take a moment to review these major points before you continue with
the next topic.
• OSHA covers the following steel erection activities:
o Hoisting, laying out, placing, connecting, welding, burning, guying,
bracing, bolting, plumbing, and rigging structural steel, steel
joists, and metal buildings
o Installing metal decking, curtain walls, window walls, siding
systems, miscellaneous metals, ornamental iron and similar
materials
o Moving point-to-point while performing these activities
• Under current practices in the industry, erection decisions are often
made in the field when the steel arrives. OSHA believes that preplanning
and coordination should be carried out before any steel erection
activities and has made the following requirements:
o The controlling contractor must follow OSHA requirements in
regard to the site layout prior to steel erection activities.
o All hoisting operations that are to take place during steel erection
operations must be planned in advance and be in compliance with
the OSHA requirements for hoisting.
Topic 2: OSHA Requirements
This topic reviews OSHA requirements for some common steel erection
activities. Upon completing this topic, you should be able to:
• Describe OSHA requirements for rigging and hoisting steel members and
materials
• Describe OSHA requirements for structural steel assembly
• Describe OSHA requirements for column stability
• Describe OSHA requirements for beams and columns
Rigging and Hoisting - General Requirements
Rigging and hoisting of steel members and materials are essential activities in
the steel erection process. Defects in hoisting equipment can harm steel
erection workers in many ways. This section sets safety requirements to
address the hazards associated with these activities.
A competent person must visually inspect cranes that are being used in steel
erection activities prior to each shift, and the inspection must include
observation for deficiencies during operation. This person might be the
operator or oiler of the hoisting equipment being used or, on a large project,
the master mechanic who checks each crane.
If any deficiency is identified, an immediate determination must be made by
the competent person as to whether the deficiency constitutes a hazard. If the
deficiency is determined to constitute a hazard, then the hoisting equipment
will be removed from service until the deficiency has been corrected.
During steel erection operations the crane operator is responsible for those
operations that are under the operator's direct control. Whenever there is any
doubt as to safety, the operator has the authority to stop and refuse to handle
loads until safety has been assured. A qualified rigger (a rigger who also is a
qualified person) must inspect the rigging prior to each shift.
Safety latches on hooks are not to be deactivated or made inoperable except:
• When a qualified rigger has determined that the hoisting and placing of
purlins and single joists can be performed more safely by doing so, or
• When equivalent protection is provided in a site-specific erection plan.
What is a Qualified Rigger?
A qualified rigger is defined as a "qualified person" who is performing the
inspection of the rigging equipment. Based on the definition of a "qualified
person," a qualified rigger must have demonstrated the ability to solve or
resolve rigging problems. Since there are no degree or certification programs
for "riggers," they must have extensive experience to support this
demonstration.
Competent Person
A competent person must visually inspect cranes that are being used in steel
erection activities prior to each shift, and the inspection must include
observation for deficiencies during operation. At a minimum this inspection will
include the following:
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All control mechanisms for maladjustments
Control and drive mechanism for excessive wear of components and
contamination by lubricants, water, or other foreign matter
Safety devices, including but not limited to boom angle indicators, boom
stops, boom kick-out devices, anti-two block devices, and load moment
indicators where required
Air, hydraulic, and other pressurized lines for deterioration or leakage,
particularly those that flex in normal operation
Hooks and latches for deformation, chemical damage, cracks, or wear
Wire rope reeving for compliance with hoisting equipment
manufacturer's specifications
Electrical apparatus for malfunctioning, signs of excessive deterioration,
dirt, or moisture accumulation
Hydraulic system for proper fluid level
Tires for proper inflation and condition
Ground conditions around the hoisting equipment for proper support,
including ground settling under and around outriggers, ground water
accumulation, or similar conditions
The hoisting equipment for level position
The hoisting equipment for level position after each move and setup
Rigging and Hoisting - Working Under Loads
During steel erection activities, the routes for suspended loads must be
preplanned to ensure that no employee is required to work directly below a
suspended load except for employees who are engaged in the initial
connection of the steel or who are involved in hooking or unhooking the load.
When working under suspended loads, the following criteria must be met:
• Materials being hoisted must be rigged to prevent unintentional
displacement.
• Hooks with self-closing safety latches must be used to prevent
components from slipping out of the hook.
• All loads must be rigged by a qualified rigger.
Rigging and Hoisting - Multiple Lift Rigging Procedure
The multiple lift rigging procedure (also known as Christmas treeing, multiple
lifting, or tandem loading) can present significant hazards to workers.
A multiple lift can be performed only if the following criteria are met:
• A multiple lift rigging assembly is used.
• No more than five members are hoisted per lift.
• Only beams and similar structural members are lifted.
• All employees engaged in the multiple lift have been trained in these
procedures.
Key Point: No crane may be used for a multiple lift if its use would go
against the manufacturer's specifications and limitations.
Components of the multiple lift rigging assembly must be specifically designed
and assembled with a maximum capacity for total assembly and for each
individual attachment point. This capacity, certified by the manufacturer or a
qualified rigger, must be based on the manufacturer's specifications with a 5
to 1 safety factor for all components. The total load must not exceed:
• The rated capacity of the hoisting equipment specified in the hoisting
equipment load charts
• The rigging capacity specified in the rigging rating chart
What is the correct use of a multiple lift rigging assembly?
The multiple lift rigging assembly must be rigged with members:
• Attached at their centers of gravity and maintained reasonably level
• Rigged from top down
• Rigged at least 7 feet apart
The members on the multiple lift rigging assembly must be set from the
bottom up, and controlled load lowering must be used whenever the load is
over the connectors.
Structural Steel Assembly - General Requirements
It is vital that structural stability be maintained at all times during the erection
process. This section describes the requirements for the assembly of structural
steel around three areas:
• Walking/Working Surfaces
• Plumbing-Up
• Metal Decking
What additional requirements apply to multi-story structures?
The following requirements apply to multi-story structures:
• The permanent floors must be installed as the erection of structural
members progresses, and there must be no more than eight stories
between the erection floor and the uppermost permanent floor, except
where the structural integrity is maintained as a result of the design
• At no time can there be more than 4 floors or 48 feet, whichever is less,
of unfinished bolting or welding above the foundation or uppermost
permanently secured floor, except where the structural integrity is
maintained as a result of the design.
• A fully planked or decked floor or nets must be maintained within two
stories or 30 feet, whichever is less, directly under any erection work
being performed.
Structural Steel Assembly - Walking/Working Surfaces
In order to prevent tripping hazards, shear connectors must not be attached to
the top flanges of beams, joists, or beam attachments so that they project
vertically from or horizontally across the top flange until after the metal
decking or other surface has been installed.
Shear connectors include headed steel studs, steel bars or steel lugs,
reinforcing bars, deformed anchors, and threaded studs.
When shear connectors are used in the construction of composite floors, roofs,
and bridge decks, the proper procedure is for the employees to lay out and
install the shear connectors after the metal decking has been installed, using
the metal decking as a working platform.
Shear connectors must not be installed from within a controlled decking zone
(CDZ).
Structural Steel Assembly - Plumbing-Up
The competent person may determine that plumbing-up equipment has to be
installed in conjunction with the steel erection process to ensure the stability
of the structure.
When it is to be used, the plumbing-up equipment must be in place and
properly installed before the structure is loaded with construction material
such as loads of joists, bundles of decking, or bundles of bridging. Only the
competent person can approve the removal of any plumbing-up equipment
that has been installed.
Structural Steel Assembly - Metal Decking
During steel erection operations involving metal decking, bundle packaging
and strapping must not be used for hoisting unless it has been designed
specifically for this purpose.
Sometimes, to expedite unloading and hoisting, items such as dunnage or
flashing will be sent up with the bundle to help support it on the structure and
to protect the decking that has already been installed. Hoisting loose items (or
piggybacking) is not permitted unless the items are secured to prevent them
from falling off the bundle in the event that it catches on the structure and
tilts.
When hoisting the metal decking bundles, they must be landed on framing
members so that enough support is provided to allow the bundles to be
unbanded without dislodging the bundles from the supports. At the end of
each shift or at any time when environmental or job site conditions might
require it, the metal decking must be secured against displacement.
Roof and floor holes and openings
During steel erection operations, any metal decking around roof and floor
holes and openings must be installed using the following work practices:
Framed metal deck openings must have structural members turned down to
allow for continuous deck installation except in instances where this would not
be possible due to structural design constraints or constructibility.
Roof and floor holes and openings must be decked over. Where the large size,
configuration, or other structural design does not allow openings to be decked
over (such as elevator shafts, stairwells, etc.), employees must be protected
from fall hazards by guardrail systems, safety net systems, personal fall arrest
systems, positioning device systems, or fall restraint systems.
Metal decking holes and openings must not be cut until immediately prior to
being permanently filled with the equipment or structure needed or intended
to fulfill its specific use.
Covering roof and floor openings
When covers are going to be use for roof and floor openings, they must be
capable of supporting, without failure, twice the weight of the employees,
equipment, and materials that will be placed on them at any one time.
All covers must be secured in place after they have been installed in order to
prevent accidental displacement by wind, equipment, or employees. In
addition, covers must be painted with high-visibility paint or marked with the
word HOLE or COVER to provide employees with a visual warning of the
hazard.
Smoke dome or skylight fixtures that have been installed typically do not meet
the necessary strength requirements are not considered covers unless they
can meet the strength requirements.
Decking gaps around columns, Installation of metal decking, and Derrick floors
Decking gaps around columns
In order to eliminate fall hazards, wire mesh or exterior plywood must be
installed around columns where planks or metal decking do not fit tightly. The
materials used must be of sufficient strength to provide fall protection for
personnel and to prevent objects from falling through.
Installation of metal decking
Metal decking must be laid tightly and secured immediately upon placement to
prevent accidental movement or displacement, and the metal decking panels
must be placed to ensure full support by structural members.
Derrick floors
A derrick floor must be fully decked and/or planked and the steel member
connections completed to support the intended floor loading. Any temporary
load that is placed on a derrick floor must be distributed over the underlying
support members to prevent the local overloading of the deck material.
Column Anchorage - General Requirements
This section addresses the hazards associated with column stability and,
specifically, the proper use of anchor rods (anchor bolts) to ensure column
stability.
Inadequate anchor rod (anchor bolt) installation has been identified as a
contributing factor in structural collapses. Collapses due to poor footings and
anchor bolts are currently the primary cause of connector incidents. It is
important to ensure that columns are adequately stabilized during their
erection to withstand construction loads.
The general requirements for erection stability are:
• All columns must be anchored by a minimum of four anchor rods
(anchor bolts). In addition, the columns must be set on level finished
floors, pregrouted leveling plates, leveling nuts, or shim packs that are
adequate to transfer the construction loads.
• All columns must be evaluated by a competent person to determine if
guying or bracing is needed. Where it is determined by the competent
person that guying or bracing is needed, it must be installed to ensure
stability.
Column Stability - Anchor Rods Maintenance
OSHA has specified the following requirements for the repair, replacement, or
field modification of anchor rods (anchor bolts):
• Anchor rods (anchor bolts) may not be repaired, replaced, or fieldmodified without the prior approval of the project structural engineer.
•
Prior to the erection of a column, the controlling contractor must provide
written notification to the steel erector if there has been any repair,
replacement, or modification of the anchor rods (anchor bolts) of that
column.
Connecting Beams and Columns - General Requirements
This section describes the requirements for connections of beams and columns
to minimize the hazard of structural collapse during the early stages of the
steel erection process.
Recognizing that inappropriate or inadequate connections of beams and
columns is hazardous and can lead to collapses and worker fatalities, OSHA
has established requirements to address these hazards. The general
requirements are:
• During the final placing of solid web structural members, the load must
not be released from the hoisting line until the members are secured
with at least two bolts per connection that are the same size and
strength as shown in the erection drawings. The bolts must be drawn up
wrench-tight.
• A competent person must determine if more than two bolts are
necessary to ensure the stability of cantilevered members. If so,
additional bolts must be installed prior to release from the hoisting line.
Beams and Columns - Double Connections
The following requirements apply to double connections at columns and/or at
beam webs over a column:
• When two structural members are connected and share common
connection holes, at least one bolt must remain connected to the first
member unless a seat or equivalent connection device is supplied to
secure the first member and prevent the column from being displaced.
• If a seat or equivalent device is used, the seat (or device) must be
designed to support the load during the double connection process. It
must be adequately bolted or welded to both a supporting member and
the first member before the nuts on the shared bolts are removed to
make the double connection.
Key Point: Solid web structural members that are used as diagonal bracing
have to be secured by at least one bolt per connection.
Beams and Columns - Perimeter Columns
During steel erection activities, perimeter columns must not be erected unless:
• The perimeter columns extend a minimum of 48 inches above the
finished floor to permit installation of perimeter safety cables prior to
erection of the next tier.
• The perimeter columns have holes or other devices in or attached to
perimeter columns at 42-45 inches above the finished floor and the
midpoint between the finished floor and the top cable to permit
installation of perimeter safety.
Topic Summary
Please take a moment to review these key points before you continue with the
next topic.
• A competent person must visually inspect cranes that are being used in
steel erection activities prior to each shift, and the inspection must
include observation for deficiencies during operation.
• During steel erection activities, the routes for suspended loads must be
preplanned to ensure that no employee is required to work directly
below a suspended load, except for employees who are engaged in the
initial connection of the steel or who are involved in hooking or
unhooking the load.
• No crane may be used for a multiple lift if its use would go against the
manufacturer's specifications and limitations.
• It is vital that structural stability be maintained at all times during the
erection process. OSHA has set up requirements for the assembly of
structural steel around three areas:
o Walking/Working Surfaces
o Plumbing-Up
o Metal Decking
• Inadequate anchor rod (anchor bolt) installation has been identified as a
contributing factor to structural collapses. It is important to ensure that
columns are adequately stabilized during their erection to withstand
construction loads:
•
o All columns must be anchored by a minimum of four anchor rods
(anchor bolts). In addition, the columns must be set on level
finished floors, pregrouted leveling plates, leveling nuts, or shim
packs that are adequate to transfer the construction loads.
o All columns must be evaluated by a competent person to
determine if guying or bracing is needed. Where it is determined
by the competent person that guying or bracing is needed, it must
be installed to ensure stability.
Inappropriate or inadequate connections of beams and columns is
hazardous and can lead to collapses and worker fatalities. Remember
these two general requirements:
o During the final placing of solid web structural members, the load
must not be released from the hoisting line until the members are
secured with at least two bolts per connection that are the same
size and strength as shown in the erection drawings. The bolts
must be drawn up wrench-tight.
o A competent person must determine if more than two bolts are
necessary to ensure the stability of cantilevered members. If so,
additional bolts must be installed prior to release from the hoisting
line.
Topic 3: Open Web Steel Joists
Some of the most serious risks facing employees engaged in steel erection are
encountered during the erection of open web steel joists, particularly landing
loads on unbridged joists and improperly placing loads on joists. Based on an
analysis of fatalities from January 1984 to December 1990, OSHA determined
that of the approximately 40 fatalities caused by collapse, more than half were
related to the erection of steel joists.
OSHA has developed the combination of specification and performance
requirements to provide more comprehensive protection to workers engaged
in these activities. This topic presents these requirements. Upon completing
this topic, you should be able to:
• Describe OSHA requirements for working with/around open web steel
joists
General Requirement
During construction operations where steel joists are used and columns are
not framed in at least two directions with solid web structural steel members,
a steel joist must be field-bolted at the column to provide lateral stability to
the column during erection. For the installation of this joist, the following
requirements must be met:
• A vertical stabilizer plate must be provided on each column for steel
joists. The plate must be a minimum of 6 inches by 6 inches and must
extend at least 3 inches below the bottom chord of the joist, with a
13/16-inch hole to provide an attachment point for guying or plumbing
cables.
• The bottom chords of steel joists at columns must be stabilized to
prevent rotation during erection.
• Hoisting cables must not be released until the seat at each end of the
steel joist is field-bolted and each end of the bottom chord restrained by
the column stabilizer plate.
In some instances constructibility does not allow a steel joist to be installed at
the column. When this situation occurs, the following requirements must be
followed:
• An alternate means of stabilizing joists must be installed on both sides
near the column and must:
o Provide stability
o Be designed by a qualified person
o Be shop-installed
o Be included in the erection drawings
• Hoisting cables must not be released until the seat at each end of the
steel joist is field-bolted and the joist is stabilized.
In situations where the steel joists that are located at or near columns
spanning 60 feet or less, the joist must be designed to be strong enough to
allow one employee to release the hoisting cable without the need for erection
bridging. If the span is more than 60 feet, the joists must be set in tandem
with all bridging installed unless there is an alternative method of erection that
provides equivalent stability to the steel joist and a qualified person has
designed it. Such an alternative method must be included in the site-specific
erection plan.
In open web operations, a steel joist or steel joist girder must not be placed
on any support structure unless the structure has been stabilized. When steel
joists are landed on a structure, they must be secured to prevent any
unintentional displacement prior to installation.
Key Point: Under no circumstances can a modification that affects the
strength of a steel joist or steel joist girder be made without the
approval of the project structural engineer.
Attachment of Steel Joists and Steel Joist Girders
During steel erection operations, each end of "K" series steel joists must be
attached to the support structure with a minimum of two one-eighth-inch fillet
welds one inch long or with two one-half-inch bolts.
Each end of "LH" and "DLH" series steel joists and steel joist girders must be
attached to the support structure with a minimum of two one-quarter-inch
fillet welds two inches long, or with two three-quarter-inch bolts.
Each steel joist must be attached to the support structure, at least at one end
on both sides of the seat, immediately upon placement in the final erection
position and before additional joists are placed. In addition, panels that have
been pre-assembled from steel joists with bridging must be attached to the
structure at each corner before the hoisting cables are released.
Steel Joists Erection
During the erection of steel joists, both sides of the seat of one end of each
steel joist that requires bridging must be attached to the support structure
before hoisting cables are released.
For joists that are over 60 feet, both ends of the joist must be attached before
the hoisting cables are released.
On steel joists that do not require erection bridging, only one employee is
allowed on the joist until all bridging is installed and anchored. Employees
must not be allowed on steel joists where the span of the steel joist is equal to
or greater than the span shown in Tables A and B.
When permanent bridging terminus points cannot be used during erection,
additional temporary bridging terminus points are required to provide stability.
Steel Erection Bridging
When the span of the steel joists is in different ranges, different requirements
for bridging apply.
Where the span of the steel joist is equal to or greater than the span shown in
Tables A and B, the following must apply:
• A row of bolted diagonal erection bridging must be installed near the
midspan of the steel joist.
• Hoisting cables must not be released until this bolted diagonal erection
bridging is installed and anchored.
• No more than one employee is allowed on these spans until all other
bridging is installed and anchored.
Where the span of the steel joist is between 60-100 feet, the following must
apply:
• All rows of bridging must be bolted diagonal bridging.
• Two rows of bolted diagonal erection bridging must be installed near the
third points of the steel joist.
• Hoisting cables must not be released until this bolted diagonal erection
bridging is installed and anchored.
• No more than two employees are allowed on these spans until all other
bridging is installed and anchored.
Where the span of the steel joist is between 100-144 feet, the following must
apply:
• All rows of bridging must be bolted diagonal bridging.
• Hoisting cables must not be released until all bridging is installed and
anchored.
• No more than two employees are allowed on these spans until all
bridging is installed and anchored.
For steel members spanning more than 144 feet, the erection methods used
must be the same as those for beams and columns.
Where any steel joist specified in is a bottom chord-bearing joist, a row of
bolted diagonal bridging must be provided near the supports. This bridging
must be installed and anchored before the hoisting cable is released.
When bolted diagonal erection bridging is required, the following requirements
apply:
• The bridging must be indicated on the erection drawing.
• The erection drawing must be the exclusive indicator of the proper
placement of this bridging.
• Shop-installed bridging clips, or functional equivalents, must be used
where the bridging bolts to the steel joists.
• When two pieces of bridging are attached to the steel joist by a common
bolt, the nut that secures the first piece of bridging must not be
removed from the bolt for the attachment of the second.
• Bridging attachments must not protrude above the top chord of the steel
joist.
Landing and Placing Loads
The following requirements apply to landing and placing loads:
When placing a load on steel joists during construction, you must ensure that
the load is distributed so that it will not exceed the carrying capacity of any
steel joist.
No construction loads are allowed on the steel joists until all bridging is
installed and anchored and all joist-bearing ends are attached.
The weight of a bundle of joist bridging must not exceed a total of 1,000
pounds and the bundle must be placed on a minimum of three steel joists that
are secured at one end with the edge of the bridging bundle positioned within
one foot of the secured end.
The edge of the construction load must be placed within one foot of the
bearing surface of the joist end.
No construction loads are allowed on the steel joists until all bridging is
installed and anchored and all joist-bearing ends attached. However, there is
an exception when all of the following conditions are met:
• The employer has first determined from a qualified person and
documented in a site-specific erection plan that the structure or portion
of the structure is capable of supporting the load.
• The bundle of decking is placed on a minimum of three steel joists.
• The joists supporting the bundle of decking are attached at both ends.
• At least one row of bridging is installed and anchored.
• The total weight of the bundle of decking does not exceed 4,000 pounds.
• Placement of the bundle of decking must be in accordance with OSHA
Topic Summary
Please take a moment to review these key points before you continue with the
next topic.
• During construction operations where steel joists are used and columns
are not framed in at least two directions with solid web structural steel
members, a steel joist must be field-bolted at the column to provide
lateral stability to the column during erection.
o A vertical stabilizer plate must be provided on each column for
steel joists. The plate must be a minimum of 6 inches by 6 inches
and must extend at least 3 inches below the bottom chord of the
joist with a 13/16-inch hole to provide an attachment point for
guying or plumbing cables.
o The bottom chords of steel joists at columns must be stabilized to
prevent rotation during erection.
o Hoisting cables must not be released until the seat at each end of
the steel joist is field-bolted and each end of the bottom chord
restrained by the column stabilizer plate.
• During the erection of steel joists, both sides of the seat of one end of
each steel joist that requires bridging must be attached to the support
structure before hoisting cables are released.
• There are different safety requirements for bridging that apply to
different ranges of spans.
• When placing a load on steel joists during construction, you must ensure
that the load is distributed so that it will not exceed the carrying
capacity of any steel joist.
Topic 4: Systems-Engineered Metal Buildings
If you look at steel erection activities, those associated with systemsengineered metal buildings are different from those associated with
conventional steel erection. Now, over 50 percent of industrial buildings in
steel erection are systems-engineered.
This topic reviews safety requirements to erect systems-engineered metal
buildings safely. Upon completing this topic, you should be able to:
• Describe OSHA requirements for systems-engineered metal buildings
Systems-Engineered Metal Buildings
Systems-engineered metal buildings include structures ranging from small
sheds to larger structures such as warehouses, gymnasiums, churches,
airplane hangars, and arenas. They frequently have lighter, cold-formed
members such as girts, eave struts, and purlins. Larger members in this type
of construction are called rigid frames, a term not used in conventional steel
erection.
The erection of systems-engineered metal structures presents certain unique
hazards. Although some of the hazards are similar to general steel erection,
other hazards, such as those associated with anchor bolts, construction loads,
and double connections, are different.
There are a large number of small, specialized steel erectors who perform
systems-engineered metal building erection exclusively.
Erection of Systems-Engineered Metal Buildings
The following requirements apply to the erection of systems-engineered metal
buildings:
• Each structural column must be anchored by a minimum of four anchor
rods (anchor bolts).
• Rigid frames must have 50 percent of their bolts or the number of bolts
specified by the manufacturer (whichever is greater) installed and
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tightened on both sides of the web adjacent to each flange before the
hoisting equipment is released.
Construction loads must not be placed on any structural steel framework
unless such framework is safely bolted, welded, or otherwise adequately
secured.
In girt and eave strut-to-frame connections that share common
connection holes, at least one bolt must remain connected to the first
member unless a manufacturer-supplied, field-attached seat or similar
connection device is present so that the girt or eave strut is always
secured against displacement.
Both ends of all steel joists or cold-formed joists must be fully bolted
and/or welded to the support structure before releasing the hoisting
cables, allowing an employee on the joists, or allowing any construction
loads on the joists.
Purlins and girts must not be used as an anchorage point for a fall arrest
system unless written approval is obtained from a qualified person.
Purlins may be used as a walking/working surface only when installing
safety systems, after all permanent bridging has been installed and fall
protection provided.
Construction loads may be placed only within a zone that is within eight
feet of the centerline of the primary support member.
Topic Summary
Please take a moment to review these key points before you continue with the
next topic.
• Each structural column must be anchored by a minimum of four anchor
rods (anchor bolts).
• Both ends of all steel joists or cold-formed joists must be fully bolted
and/or welded to the support structure before releasing the hoisting
cables, allowing an employee on the joists, or allowing any construction
loads on the joists.
• Construction loads may be placed only within a zone that is within eight
feet of the centerline of the primary support member.
Topic 5: Fall Protection In Steel Erection
This topic reviews fall protection in steel erection. Upon completing this topic,
you should be able to:
• Describe general requirements for fall protection in steel erection
• Describe the fall protection requirements for connectors
• Define a controlled decking zone (CDZ)
General Requirements
Except for connectors, each employee engaged in a steel erection activity who
is on a walking/working surface with an unprotected side or edge more than
15 feet above a lower level must be protected from fall hazards by guardrail
systems, safety net systems, personal fall arrest systems, positioning device
systems, or fall restraint systems.
On multi-story structures, perimeter safety cables must be installed at the
final interior and exterior perimeters of the floors as soon as the metal decking
has been installed.
Steel joists and steel joist girders must not be used as anchorage points for a
fall arrest system unless written approval to do so is obtained from a qualified
person.
Fall Protection Requirements for Connectors
There are specific fall protection requirements for employees who are
connectors:
• A connector must be protected from fall hazards of more than 2 stories
or 30 feet above a lower level, whichever is less. The methods of fall
protection include guardrail systems, safety net systems, personal fall
arrest systems, positioning device systems, or fall restraint systems.
• A connector must have completed connector training.
• When a controlled decking zone is not in use, at heights over 15 and up
to 30 feet above a lower level, a connector must be provided with a
personal fall arrest system, positioning device system, or fall restraint
system and wear the equipment necessary to be tied off.
Controlled Decking Zone (CDZ)
A controlled decking zone may be established for the area of the structure that
is over 15 feet and up to 30 feet above a lower level where metal decking is
initially being installed and forms the leading edge of a work area.
In each CDZ, the following must apply:
• Each employee working at the leading edge in a CDZ must be protected
from fall hazards of more than 2 stories or 30 feet, whichever is less.
• Access to a CDZ must be limited to only those employees engaged in
leading edge work.
• The boundaries of a CDZ must be designated and clearly marked. The
CDZ must not be more than 90 feet wide and 90 feet deep from any
leading edge.
• The CDZ must be marked by the use of control lines or the equivalent.
• Each employee working in a CDZ must have completed CDZ training.
• Unsecured decking in a CDZ must not exceed 3,000 square feet.
• Safety deck attachments must be performed in the CDZ from the leading
edge back to the control line and must have at least two attachments for
each metal decking panel.
• Final deck attachments and installation of shear connectors must not be
performed in the CDZ.
Criteria for Fall Protection Equipment
Guardrail systems, safety net systems, personal fall arrest systems,
positioning device systems, and their components must conform to the criteria
established in OSHA Fall Protection standard (Subpart M).
Fall arrest system components must be used in fall restraint systems and must
conform to OSHA requirements. Either body belts or body harnesses must be
used in fall restraint systems.
Perimeter safety cables must meet the criteria for guardrail systems.
Falling Object Protection
The following falling object protection needs to be in place in steel erection:
• Securing loose items aloft: All materials, equipment, and tools not in use
while aloft must be secured against accidental displacement.
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Protection from falling objects other than materials being hoisted:
Construction processes below steel erection are prohibited unless
overhead protection is provided for the employees below.
Topic Summary
Please take a moment to review these key points before you continue with the
next topic.
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Except for connectors, each employee engaged in a steel erection
activity who is on a walking/working surface with an unprotected side or
edge more than 15 feet above a lower level must be protected from fall
hazards by guardrail systems, safety net systems, personal fall arrest
systems, positioning device systems, or fall restraint systems.
A connector must be protected from fall hazards of more than 2 stories
or 30 feet above a lower level, whichever is less, by guardrail systems,
safety net systems, personal fall arrest systems, positioning device
systems, or fall restraint systems.
A controlled decking zone may be established in that area of the
structure over 15 feet and up to 30 feet above a lower level where metal
decking is initially being installed and forms the leading edge of a work
area.
Guardrail systems, safety net systems, personal fall arrest systems,
positioning device systems, and their components must conform to the
criteria established in the OSHA Fall Protection standard.
Lesson Summary
This lesson contains information and instruction about steel erection. By
completing this lesson, you should have the knowledge to discuss the following
topics. Take a moment to see if you can do the following:
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List common steel erection activities and explain the importance of
preplanning in steel erection
Describe OSHA requirements for these common steel erection activities:
rigging and hoisting, structural steel assembly, column stability, and
beams and columns
Describe OSHA requirements for open web steel joints
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Describe OSHA requirements for systems-engineered metal buildings
Summarize the fall protection requirements in steel erection, including
requirements for connectors and CDZ
Demolition
Introduction
Ductwork Crushes Construction Worker
An employee was demolishing a suspended plaster ceiling, above which was a
massive section of HVAC ductwork. He was directly below the ductwork,
removing the support pipe for an air-handling unit that was obstructing his
demolition activities. The ductwork collapsed, killing him. The employee had
not performed or reviewed an engineering survey to determine the structural
integrity of the ductwork before beginning work.
Distance Fails to Protect Worker
A demolition worker was watering down a building during its demolition from
approximately 50 feet back. He failed to see a pipe coming at him. The 3-inch
diameter, 17-foot pipe, weighing approximately 100 pounds, struck him in the
chest and killed him.
Demolition doesn't just mean destroying a structure; it implies planning for
predictable, controllable results that protect people and uninvolved property.
Lesson Overview
Welcome to the "Demolition" lesson of the Turner OSHA Certification course. This
lesson describes the basics of demolition and the specific OSHA requirements for
demolition work. You will also learn more about preparing for demolition, the
equipment used in these activities, hazards of special structure demolition, and
procedures for ensuring safe blasting.
Upon completing this lesson, you will be able to:
• Define the need for a survey prior to beginning any demolition job
• List particular areas of structures that are regulated by OSHA requirements
when demotion is being done
• Describe demolition equipment used to bring down structures without
explosives
• List some of the hazards that exist in special structures demolition
• Discuss safe blasting procedures and the hazards that exist on worksites
Why Learn This Lesson?
This lesson addresses demolition information specific to the construction industry.
In demolition work, unknown factors compound the many hazards associated with
general construction work. Hazards may arise if, during initial construction, deviations
from the structure's design were introduced and subsequent modifications made.
Additionally, materials hidden within structural members and unknown strengths or
weaknesses of construction materials come into play when removing the structures.
To counter these unknowns, this lesson offers information valuable to make all
personnel involved in a demolition project fully aware of the hazards and safety
precautions needed in demolition work.
Topic 1: Preparing for Demolition
Beginning any type of demolition project without everyone involved knowing every
aspect of the plan is an invitation for something to go wrong. Planning for a
demolition job is more important than actually doing the demolition. Why? Because a
good, thorough plan is necessary to achieve a safe, successful demolition project. For
this reason, a competent person experienced in all phases of the demolition work to
be performed should complete all planning work.
OSHA mandates that a competent person conduct an engineering survey prior to
beginning a demolition project. This survey should determine the condition of the
overall structure and the possibility of unplanned collapse of any portion of the
structure. Safe floor loads should be determined to prevent overloading as demolition
work progresses.
Before beginning every demolition job, the demolition contractor should take a
number of steps to safeguard the health and safety of workers at the job site.
In this topic, you will learn what these preparatory operations require including the:
• Overall planning of the demolition job, such as the methods to be used to bring
down the structure
• Equipment necessary to do the job
• Measures to perform the work safely
The American National Standards Institute (ANSI), in its ANSI A10.6-1983 - Safety
Requirements for Demolition Operations, states:
"No employee shall be permitted in any area that can be adversely affected
when demolition operations are being performed. Only those employees
necessary for the performance of the operations shall be permitted in these
areas."
Engineering Survey
Prior to beginning all demolition operations, OSHA requires that a competent person
conduct an engineering survey of the structure.
The purpose of this survey is to determine the condition of the framing, floors, and
walls so that necessary measures can be taken to prevent the premature collapse of
any portion of the structure.
It is also advisable to similarly check any adjacent structure or improvements.
Photographing existing damage in neighboring structures is advisable.
The demolition contractor must maintain a written copy of this survey.
Planning the Job
The engineering survey provides the demolition contractor with the opportunity to
evaluate the entire job. The contractor should plan for:
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Wrecking the structure
Equipment to do the work
Manpower requirements
Safety of all workers on the job site
Safety equipment needs
Potential hazards such as fires, cave-ins, and injuries
Locating the nearest hospital, infirmary, clinic, or physician
Protection of the public
If the structure to be demolished has been damaged by fire, flood, explosion, or some
other cause, appropriate measures, including bracing and shoring of walls and floors,
should be taken to protect workers and any adjacent structures. The history of any
type of hazardous chemicals, gases, explosives, flammable material, or similar
dangerous substances used or stored on-site should be determined. If the nature of a
substance cannot easily be defined, samples should be taken and analyzed by a
qualified person prior to demolition.
During the planning stage of the job, all safety equipment needs should be
determined. The required number and type of respirators, lifelines, warning signs,
safety nets, special face and eye protection, hearing protection, and other worker
protection devices should be established as the engineering survey is prepared.
A comprehensive plan is necessary for any confined space entry.
Utility Location
One of the most important elements of pre-job planning is locating all utility services.
All electric, gas, water, steam, sewer, and other services lines should be shut off,
capped, or otherwise controlled at or outside the building before demolition work
starts.
In each case, any utility company involved should be notified in advance, and any
approval or services needed should be obtained.
If it is necessary to maintain any power, water, or other utilities during demolition,
such lines should be temporarily relocated as necessary and/or protected.
The location of all overhead power sources should also be determined, as they can be
especially hazardous during any machine demolition. All workers should be informed
of the location of any existing or relocated utility service.
Medical Services and First Aid
Think, plan, and provide for prompt medical attention in case of serious injury prior to
the start of demolition by:
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Locating the nearest hospital, infirmary, clinic, or physician as part of the
engineering survey
Providing the job supervisor with the most direct route to medical facilities
Providing proper equipment for prompt transportation of an injured worker
Providing an available communication system to contact any necessary
ambulance service at the job site -- conspicuously post the telephone numbers
of hospitals, physicians, or ambulances
If there is no infirmary, clinic, hospital, or physician reasonably accessible to the
worksite, a person with a valid certificate in first aid training from the U.S. Bureau of
Mines, the American Red Cross, or equivalent training should be available at the
worksite to give first aid.
A properly stocked first aid kit, as determined by an occupational physician, must be
available at the job site. The first aid kit should contain:
• Approved supplies in a weatherproof container
• Individual sealed packages for each type of item
• Rubber gloves to prevent the transfer of infectious diseases
• Provisions to provide for quick drenching or flushing of the eyes if anyone is
working around corrosive materials
• Water containing no additives for eye flushing
The contents of the kit should be checked before being sent out on each job and rechecked at least weekly to ensure the expended items are replaced.
Police And Fire Contact
The telephone numbers of the local police, ambulance, and fire departments should
be available at each job site. This information can prove useful to the job supervisor
in the event of any traffic problems, such as the movement of equipment to the job,
uncontrolled fires, or other police/fire matters. The police number may also be used
to report any vandalism, unlawful entry to the job site, or incidents requiring police
assistance.
Fire Prevention And Protection
A fire plan should be established prior to beginning a demolition job. This plan should
outline the assignments of key personnel in the event of a fire and provide an
evacuation plan for workers on the site.
Common sense should be the general rule in all fire prevention planning and should
include:
Preparation, Evaluation, and Correction
• Evaluating and taking necessary corrective measures for all potential sources of
ignition
• Installing and regular inspection by a competent person of electrical wiring and
equipment for providing light, heat, or power
• Locating sufficient firefighting equipment near any flammable or combustible
liquid storage area
• Using only approved containers and portable tanks to store and handle
flammable and combustible liquids
• Shutting down all internal combustion equipment prior to refueling and storing
fuel for this equipment in a safe location
• Evaluating and taking necessary corrective measures for all potential sources of
ignition
• Prohibiting smoking at or in the vicinity of hazardous operations or materials
and, where smoking is permitted, providing safe receptacles for smoking
materials
Physical Proximity to Hazards
• Maintaining clearance of at least six inches between piping and combustible
material when the exhausts are piped outside the building
• Locating equipment powered by an internal combustion engine so that the
exhausts discharge well away from combustible materials and from workers
• Situating heating devices so they are not likely to overturn, installing them
according to their listing, and including clearance to combustible material or
equipment -- competent personnel should maintain any temporary heating
equipment used
Access
• Maintaining roadways free from accumulation of rubbish, equipment, or other
materials. Roadways between and around combustible storage piles should be
at least 15 feet wide. When storing debris or combustible material inside a
structure, such storage should not obstruct or adversely affect the means of
exit.
• Establishing a suitable job site location provided with plans, emergency
information, and equipment needed. Ensure access for heavy fire-fighting
equipment on the immediate jobsite at the start of the job and maintain it until
the job is completed.
• Providing and maintaining free access from the street to fire hydrants and to
outside connections for standpipes, sprinklers, or other fire extinguishing
equipment, whether permanent or temporary, at all times. This means:
1. Pedestrian walkways should not impede access to hydrants.
2. No material or construction should interfere with access to hydrants,
Siamese connections, or fire-extinguishing equipment.
Firefighting resources
• Making available a temporary or permanent water supply of volume, duration,
and pressure sufficient to operate the fire-fighting equipment properly
• Providing standpipes with outlets on large multi-story buildings to provide for
fire protection on upper levels and, if the water pressure is insufficient,
providing a pump
• Providing an ample number of fully charged portable fire extinguishers
throughout the operation. All motor-driven mobile equipment should be
equipped with an approved fire extinguisher.
• Establishing an alarm system (telephone system, siren, two-way radio, etc.) so
that employees on the site and the local fire department can be alerted in case
of an emergency. Conspicuously post the alarm code and reporting
instructions. The alarm system should be serviceable at the job site during the
demolition. Retain fire cutoffs in the buildings undergoing alterations or
demolition until operations necessitate their removal.
Topic Summary
Please take a moment to review these major points before you continue with the next
topic.
• An engineering survey should be performed before any demolition project
begins, and a written copy must be maintained by the demolition contractor
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This survey should determine the condition of the framing, floors, and walls to
take any measures necessary to prevent premature collapse of any portion of
the structure.
The contractor should plan for:
o Wrecking the structure
o Equipment to do the work
o Manpower requirements
o Safety of all workers on the job site
o Safety equipment needs
o Potential hazards such as fires, cave-ins, and injuries
o Locating the nearest hospital, infirmary, clinic, or physician
o Protecting the public
Final preparations include locating and controlling all utility services and
providing medical services and fire and police protection.
Topic 2: Specific OSHA Requirements
OSHA has specific requirements for the various members within a structure. This
topic covers the requirements for stairwells and chutes when demolition work is
planned in a structure. It also covers regulations that govern specialized removal of
walls, chimneys, and masonry sections; the manual and mechanical removal of
construction members in demolition work; as well as removal of materials through
floor openings.
After completing this topic, you should be able to:
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Describe important safety precautions for stairs and ladders in demolition work
Define guidelines for removing materials through floor openings
Describe hazards incurred in removing special structures
Define hazards to avoid in mechanical demolition
Access
During demolition operations, only the stairways, passageways, and ladders that have
been designated as a means of access to the building can be used. Other access ways
must be entirely closed at all times.
In a multi-story building, when a stairwell is being used, it must be properly
illuminated by either natural or artificial means. The stairwell also must be completely
covered over to prevent access at a point not less than two floors below the floor
where work is being performed.
Access to the floor where the work is in progress must be through a properly lighted,
protected, and separate passageway.
Chutes
No material can be dropped to any point outside the exterior walls of the structure
unless the area is effectively protected.
Chutes must be designed and constructed so that they are strong enough to eliminate
the hazard of failure from the impact of materials or debris loaded into them.
All materials chutes or their sections set at an angle of more than 45 degrees must be
entirely enclosed, except for openings equipped with closures at the floor level for the
insertion of materials. These openings cannot exceed 48 inches and must be kept
closed when not in use.
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A substantial gate must be installed in each chute near the discharge end, and
a competent person must be assigned to control the operation of the gate and
the backing and loading of trucks.
• When operations are not in progress, the area surrounding the discharge end
of a chute must be securely closed off.
• A standard guardrail must be installed to protect any chute opening into which
workmen may dump debris. Any space between the chute and the edge of floor
openings through which it passes must be solidly covered.
• Where the material is dumped from mechanical equipment or wheelbarrows, a
toeboard or bumper must be provided at each chute opening.
Removing Materials Through Floor Openings
Any openings cut in a floor to be used for material disposal cannot be larger than 25
percent of the total floor area, unless the lateral supports of the removed flooring
remain in place.
Floors weakened or made unsafe by demolition operations must be shored so they
can carry the intended imposed load from demolition operations safely.
Removing Walls, Masonry Sections, and Chimneys
These practices are required by OSHA when removing specified structure members:
• When removing masonry walls or other sections of masonry, do not permit
them to fall on the building floors in masses that would exceed the safe
carrying capacities of the floors.
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No wall section more than one story in height can stand alone without lateral
bracing, unless the wall was designed to stand without lateral support and is
safe enough to be self-supporting.
Leave all walls in a stable condition at the end of each shift.
Employees are not permitted to work on the top of a wall when weather
conditions constitute a hazard.
Do not cut or remove structural or load-supporting members on any floor until
all stories above that floor are demolished and removed.
Floor openings within ten feet of any wall being demolished must be planked
solid except when employees are kept out of the area below.
In buildings of "skeleton-steel" construction, the steel framing may be left in
place during the demolition of masonry. When this is done, all steel beams,
girders, and similar structural supports must be cleared of all loose material as
the masonry demolition progresses downward.
Provide walkways or ladders to enable employees to have safe access to any
scaffold or wall.
Do not demolish walls serving as retaining walls to support earth or adjoining
structures until the earth is properly braced or adjoining structures are properly
underpinned.
Do not use walls as retaining walls to pile debris against unless they are
capable of supporting the imposed load.
Manual and Mechanical Floor Removal
Openings cut in a floor must extend the full span of the arch between the supports.
Do not begin demolition of floor arches until they, and the surrounding floor area for a
distance of 20 feet, have been cleared of debris and any other unnecessary materials.
Do not allow employees in the area directly underneath a floor arch when arches are
being removed, and barricade the area to prevent access to it.
Employees must stand on 2 x 10 full-size undressed planks while breaking down floor
arches between beams. These planks must be located in a way that provides safe
support for the workmen if the arch between the beams were to collapse. The open
space between planks cannot exceed 16 inches.
Provide safe walkways of at least 18 inches width for use by workmen when they
must reach any point without walking upon exposed beams.
Install stringers of ample strength to support the flooring planks, and support the
ends of the stringers by floor beams or girders, and not by floor arches alone.
Do not use mechanical equipment on floors or working surfaces unless the floors or
surfaces are of sufficient strength to support the imposed load.
Floor openings must have curbs or stop-logs to prevent equipment from running over
the edge.
Removing Steel Construction
Steel construction must be dismantled column length by column length and tier by
tier. Columns may be in two-story lengths.
When floor arches have been removed, planking must be provided for the workers
engaged in razing the steel framing.
Any structural member being dismembered cannot be overstressed.
Cranes, derricks, and other hoisting equipment used must meet OSHA requirements.
Mechanical Demolition
When mechanical devices are used in demolition work, the following OSHA standards
should be followed:
• Do not permit any workers in any area that can be adversely affected by
demolition operations when balling or clamming is being performed. Only
workers necessary to perform the operations should be allowed in the area at
any other time. [add to definition list]
• The weight of the demolition ball must not exceed 50 percent of the crane's
rated load or must not exceed 25 percent of the nominal breaking strength of
the line by which it is suspended, whichever results in a lesser value.
• The crane boom and loadline must be as short as possible. The ball must be
attached to the loadline with a swivel-type connection to prevent twisting of
the loadline and must be attached by positive means in such a manner that the
weight cannot become accidentally disconnected.
• Cut free all steel affected members before pulling over walls. Remove all roof
cornices or other such ornamental stonework prior to pulling over walls.
• A competent person must continue inspections as the work progresses to
detect hazards from weakened or deteriorated floors, walls, or loosened
material.
• Do not permit any employee to work where such hazards exist until they are
corrected by shoring, bracing, or other effective means.
Topic Summary
Please take a moment to review these major points before you continue with the next
topic.
• During demolition operations, only the stairways, passageways, and ladders
that have been designated as a means of access to the building can be used.
• Any openings cut in a floor to be used for material disposal cannot be larger
than 25 percent of the total floor area, unless the lateral supports of the
removed flooring remain in place.
• All walls should be left in a stable condition at the end of each shift.
• No material can be dropped to any point lying outside the exterior walls of the
structure unless the area is effectively protected.
• Chute openings cannot exceed 48 inches and must be kept closed when not in
use.
• Chutes must be strong enough to eliminate the hazard of failure from the
impact of materials or debris loaded into them.
• Employees must stand on 2 x 10 full-size undressed planks while breaking
down floor arches between beams located in a way that provides safe support
for the workmen if the arch between the beams were to collapse.
Topic 3: Demolition Equipment
Often buildings being demolished are very old, making it hard to predict precise
reactions. Recently, demolition equipment such as shears, hammers, and crane
attachments have become safer to use, but the fear of falling and flying debris still
exists, thereby demanding workers to wear head and eye protection at all times.
This topic describes the equipment used in demolition work, applicable chemical
agents, and proper clothing and dress tips to ensure safety. Safety requirements and
control of hazards involved in the use of this equipment are also covered.
Upon
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completing this topic, you will be able to:
Describe the equipment used in demolition
Explain how various devices function in demolition activities
List the factors that may cause environmental equipment violations
Booms, Breakers and Buckets
Booms
A demolition boom pushes and pulls down parts of structures. A claw attachment that
is telescopically extendable is attached to the end portion of the boom, and the whole
assembly can be mounted on a hydraulic excavator. The boom is particularly suitable
for the demolition of comparatively light structures, such as houses. However, not
every hydraulic excavator can be equipped with a demolition boom.
Controlling Hazards
Noise emission from this demolition technique is low and determined
substantially by the machine employed. Considerable dust formation may
occur, especially when demolition work on a structure is carried out at
relatively great height. Spraying water during the operations can reduce dust,
but completely wetting the member before its demolition is more effective.
Proper knowledge of the construction and behavior of the structures to be
demolished can avoid undesirable collapses and control the direction of falling.
There should be a clear understanding of just where to apply the pulling or
pushing force and in what sequence to bring down various parts of a structure.
The person in charge should be able to judge whether additional arrangements,
such as removal and installation of certain features, are needed before
demolition proceeds.
Breakers
Breaking up is generally done with straight or curved teeth moving in a straight line
or an arc. The teeth are mounted on a concrete breaker or excavator bucket or
individually mounted on an excavator. Teeth should be made of a material with
maximum resistance to wear and must be capable of transmitting forces without
breaking. In this activity, the exerting of a sufficiently large pressure or bending force
on one or both sides of the material causes disintegration or breakup. Normally,
pressure is exerted at right angles to the longitudinal direction of the component.
Most breakers can break reinforced concrete easily. The reinforcement may be cut
with the knives inside the teeth or otherwise. In most cases, rotating the breaker by
the bucket cylinder raises the material to be broken. It receives its required hydraulic
oil and pressure from the hydraulic system of the excavator or another auxiliary
machine. The breaker has movable teeth, and these teeth are sometimes combined
with fixed teeth. The breaker can work toward the excavator and away from it.
The design of most breakers supports suspension from the bucket arm and cylinder of
a hydraulic excavator, in the so-called bucket position. However, parallelogram
suspension is often used for optimal breaking force. In this configuration, the bucket
cylinder is mounted parallel to the bucket arm but on the inside of the arm.
Safety Requirements and Controlling Hazards
Several types of breakers have been developed to meet the noise and dust
restrictions in many demolition jobs. Breaking up is not a noisy operation, and
the machines used determine the noise volume. Dust formation is also very
slight, resulting partly from the relatively slow rate of work. Dust can be
formed by falling material if collapses occur.
General construction site safety requirements and those associated with
hydraulic machines apply here too. Breaking and breaking up do not impose
any additional safety requirements, but if there is any possibility of material
falling, the cab of the machine must be protected against it.
Buckets
A rock bucket is a specially constructed bucket mounted on a hydraulic excavator. It
can be used for heavy breakup work and for shifting materials. The bucket may be
fitted with a cast steel or steel plate element at its leading edge, usually made of
high-grade, wear-resistant material, and may be fitted with fixed or interchangeable
knife and teeth. For breaking up, the bucket can be moved in a straight line or an arc.
The teeth exert the maximum breaking force when the bucket is supported on the
ground and moved in an arc.
Rubble shovel buckets are used for lighter breakup work and can also be used both
for breaking and shifting materials, as they can move horizontally and in an arc.
While various designs of rubble buckets are available, rubble shovel buckets are rakeshaped and made of bent pipe or bent rectangular steel profile. Each part is fitted
with a fixed tooth. The bucket can also be equipped with a knife at the front. This
blade is usually fitted with interchangeable teeth.
Controlling Hazards
Working with a bucket as narrow as possible is generally desirable to minimize
the torsion forces in the arm of the hydraulic crane.
Cranes
Cranes are available in many versions, types, and makes for use in conjunction with
demolition techniques. One type is fully mobile, mounted on a truck (road vehicle)
framework for independent travel. These mobile cranes are set up on site and are
usually equipped with hydraulic outriggers for extra stability. Moving the crane while
carrying a load suspended from the jib is possible only with light hoist loads. Larger,
crawler-mounted mobile cranes must be dismantled for road transport. These cranes
are better suited for on-site travel movement while carrying a hoist load suspended
from the jib.
In general, cranes do not require modification or adaptation for demolition duties, but
special lifting or fixing attachments may be required. A dragline can be used as a
crane if it has the appropriate winching equipment. In particular, a crawler-mounted
dragline can fulfill crane duties when applying certain demolition techniques.
Floating cranes are used in certain demolition techniques on or in water. Two
categories of floating cranes can be distinguished:
1. Cranes designed with limited dimensions often work on relatively narrow and
inaccessible waterways because their widths suit the width of bridges. Some of
these cranes are designed so that their jibs can be completely lowered for
passing under bridges. They may be fitted on the worksite with detachable side
buoyancy chambers to increase lifting capacity.
2. Large floating cranes can operate only on major waterways with easier access.
The jibs of these big cranes, too, can usually be lowered.
Safety Requirements and Controlling Hazards
• The noise levels that demolition plants and equipment may produce are
regulated by statutory standards. Cranes in particular have to comply with
numerous regulations. To comply, the machines are noise-suppressed and
fitted with silencers. There are compressors so fully silenced that they emit
no noise at all. A floating plant is environmentally innocuous, emitting little
or no objectionable noise to the surroundings.
• For safety reasons, positioning cranes is of major importance. No one is
allowed to be present inside the slewing circle of a hydraulic crane, a
dragline, or in a demolition plant that can travel forward as well as in
reverse, so that reversing can occur in a safe, unimpeded manner.
• When demolition equipment powered by internal combustion engines is
operated in enclosed spaces, measures such as afterburners, which deal
with exhaust gases, must be used.
• A plant engaged in demolition operations involving a risk of falling material
requires a driver's cab protected against this hazard. Crawler-mounted
cranes require that appropriate arrangements be made to travel and stand
on level surfaces. If necessary, use mats to provide support for machines on
soft ground. When employing cranes with outriggers, take care to ensure
that the outriggers cannot sink into the ground during load handling.
• Ear protectors are required when working with a crane in concrete-walled
spaces or in other such situations.
• Crane operators and crew members may be electrocuted when they work
near overhead power lines.
• To protect yourself from electrocution when operating or working around
cranes near overhead power lines, take the following precautions:
1. Operate cranes only if you have been trained in safe
operating procedures and the OSHA safety requirements.
2. Participate in all crane safety programs offered by your
employer or labor organization.
3. Know the location and voltage of all overhead power lines at
the job site before operating or working with any crane.
4. Assume that all power lines are energized and maintain the
minimum clearance required by OSHA at all times. These
OSHA standards require:
• At least ten feet for lines rated 50 kilovolts or below
• At least ten feet plus 0.4 inch for each kilovolt above 50
kilovolts (or maintain twice the length of the line
insulator, but never less than ten feet)
Crushers
Pile crushers are hydraulic breakers composed of a square steel frame with
chamfered (beveled or fluted) corners and a square central opening. These crushers
were developed to snap off the heads of concrete piles. A hydraulic power unit driven
by an internal combustion engine or an electric or pneumatic motor supplies the oil
under pressure for operating the machine. The appliance is equipped with eight
hydraulic cylinders that operate chisel blades, designed to thrust the concrete
upwards and away. With different blade settings, the reinforcing bars can be left
protruding undamaged from the beheaded piles.
Mobile crushing installations are use to reduce the size of concrete, masonry, natural
stone and other stone-like materials. The main crusher is nearly always a jaw
crusher. Secondary crushers are usually different types, such as gyratory crushers or
hammer mills.
In the simpler version, the installation generally includes a feed hopper, a vibratory
screen before the crusher, and a screen for separation into two size ranges, with belt
conveyors depositing the crushed product on a stockpile or loading it into road
vehicles, etc. In most cases, the installation consists of a single unit powered by an
internal combustion engine or an electric motor. Other installations have several units
with several crushers and more elaborate screening and washing systems. These
crushing installations are often electrically powered from their own diesel-driven
generating set, independent of external supplies of electricity. This more sophisticated
installation can attain higher product output rate and yield a better quality product
graded into several size fractions.
Chemical Agents
Quicklime seems to be the main ingredient used to cause expansion by a static
expansive agent. The chemicals harden when mixed with water and increase
considerably in volume as they harden. Several types of agents are used under
different conditions, based on the maximum temperature of the material to be
demolished. This pressure buildup is much lower than that obtained with explosives
and Cardox. However, even light reinforced concrete structures can be broken by any
of these agents.
For each variety, a certain maximum water temperature is necessary. Preparing the
mixture should follow the instructions entirely. General requirements specify to:
• Place the agents in completely dry surroundings
• Verify the holes are dry
• Achieve the desired pressure buildup, in general, by placing the mixture in predrilled holes of not less than 38 mm, nor more than 80 mm diameter, with a
distance between the holes of eight times the hole diameter
Safety Requirements and Controlling Hazards
Static expansive agents cause no sound, material ejection, dust formation, or
vibration and are an entirely environmentally acceptable technique.
The hardened chemical is, so far as is known, no longer aggressive and can be
removed from the site along with the demolished material, or it can be removed
separately.
When using static expansive agents, the aggressive character of this chemical
must be considered. It is necessary for all workers concerned to protect their faces
and hands and wear special clothing. Unauthorized access to the job should be
prevented during the chemical's active period. After the chemical has been placed,
the filled holes should not be visually inspected for the first six hours.
Hammers
Pneumatic Hammers
Pneumatic hammers allow compressed air to expand in the cylinder of the hammer,
driving the piston rapidly against the anvil and transmitting the released impact
energy to the chisel. This arrangement uses the ability of a gas (air) to be
compressed to produce movement upon expansion. The hammer works in association
with a compressor that supplies compressed air at the appropriate working pressure.
All pneumatic hammers can be used underwater. However, they must be pressurized
before they are submerged and must be kept under pressure until they have been
raised from the water. When working at greater depths, a loss of efficiency (power
loss) occurs from the counter pressure. Most types of hammers can be provided with
a mantle to suppress noise.
Hydraulic Hammers
In hydraulic hammers, the impact energy results from hydraulic oil supplied at a fairly
high pressure. Since hydraulic oil is an incompressible fluid, the pressure cannot be
converted into motion without an auxiliary medium. To make such motion possible,
hydraulic hammers are equipped with a nitrogen bulb or nitrogen chamber. The
compressible nitrogen is separated from the oil by a diaphragm and provides the
required conversion of pressure into motion. In this way the piston of the hammer
can be thrust rapidly against the anvil. The anvil transmits the released impact
energy to the chisel. The used oil is returned at low pressure to the oil reservoir. The
hydraulic hammer operates with a completely enclosed hydraulic system. Even so,
unlike the pneumatic hammer, the hydraulic hammer is not suitable for working
underwater unless its supply has been adapted for that purpose. However, the
hydraulic hammer can be switched on and off underwater, which is not possible with
the pneumatic hammer. Because this is a closed system, there is no pressure loss.
Long supply and return hoses do introduce a pressure loss, but this can be
compensated.
Electric Hammers
Although electric hammers are used for demolition work only occasionally, they can
be used to demolish both vertical and horizontal objects. In these hammers, the
stroke energy is obtained from an electric motor via an eccentric cam that produces a
reciprocating motion with a lower stroke energy than comparable pneumatic or
hydraulic hammers.
Gasoline-Powered Hammers
In gasoline-powered hammers, the stroke energy comes from the rotation of a
gasoline motor, which is converted to a reciprocating motion by an eccentric cam.
These hammers also give lower stroke energy than corresponding pneumatic or
hydraulic hammers and weigh from 10 to 40 kg. If the hammer is fitted with a
floatless carburetor it is also suitable for vertical demolition work.
Safety Requirements and Controlling Hazards
• Hand tools require gloves in demolition work, with goggles to protect the eyes
from flying materials.
• Fitting pneumatic hand hammers with suppressors can reduce the noise. In this
way the noise at a distance of 7 meters can be reduced to 80-90 dB. Noise
louder than 80 dB requires ear protection.
• Because of their large return stroke, hydraulic hand hammers are less suitable
for continuous work than pneumatic hammers or heavy mechanical hand
hammers. All mechanical hammers can give rise to some degree of vibration.
Whether vibration occurs depends on the size of the hammer, the material to
be demolished, and its mass. Vibrations from hand hammers can cause white
finger disease if air-filled grips are not used.
• Hand tools form very little dust, and pneumatic hammers disperse more dust
than hydraulic hammers because of the escaping air.
Saws
Handsaws for dealing with wood, wood-like materials, and metals are available in
many types and sizes, but those used in demolition work always have coarse teeth.
The chain saw, consisting of interconnected, movable parts with a handle at each
end, also belongs to the handsaw category. Power chain saws are manipulated by
hand, but the sawing action is mechanized with power provided by an internal
combustion engine or an electric, pneumatic, or hydraulic motor. All chain saws are
suitable only for wood or wood-like materials.
Bow saws are coarse-toothed instruments with a blade gripped in a bow-shaped
frame and are generally larger than handsaws. The crosscut saw has two handles,
one at each end.
There are sawing machines for horizontal or vertical demolition work. Both are
portable machines powered by an internal combustion engine or an electric,
pneumatic, or hydraulic motor. These devices generally are designed with most
operations such as feed, rotational speed, flushing, etc., automatically controlled.
These machines generally are equipped with a diamond saw, a metal saw blade
mounted with diamonds. The difference between the two is that the vertical saw uses
guides to aid in the vertical movement.
Safety Requirements and Controlling Hazards
• Sawing produces virtually no vibrations, but noise emissions range from low
to high levels, depending on the equipment used. Equipment powered by
internal combustion engines produces the most noise, and with diamond
sawing, noise may arise from the sawing operation itself.
• Dust formation varies by the tool used. Using grinding discs to form slots in
a relatively soft material produces substantial amounts of dust unless the
machine is equipped with a dust extraction system. Dust may also occur
from chain-sawing dry material. Water flushing provides for dust removal
and cooling. Water-flushed tools do not give rise to dust, and the water
itself hardly causes any nuisance. The limited speed of operation contributes
to making this an environmentally acceptable technique. For this reason, it
need not cause nuisance to adjacent residents or be detrimental to the
environment and is considered a safe technique.
• All tools, particularly electrically powered tools, must comply with the
statutory safety requirements. Hand tools generally require gloves, and face
protection is recommended with grinding machines. Power chain saw
operators should wear protective clothing, safety boots, helmets and ear
protectors.
• In enclosed or poorly ventilated spaces, use machines powered by internal
combustion engines only after providing arrangements for discharging
exhaust gases.
Shears
Hand Shears
Hand shears for reinforcing steel have two blades that move toward each other by the
lever action of the two arms linked to them. The arms move manually. Some shears
are equipped with interchangeable blades. Hydraulic hand shears for reinforcing steel
also have two blades, which move toward each other by a hydraulic cylinder. There
are several versions, such as electrically powered shears with their own hydraulic
system and shears supplied with hydraulic oil from a hydraulic power unit driven by
an internal combustion engine, electric motor, or pneumatic motor. Another version
exists which can generate oil pressure either manually or by an electric motor.
Hydraulic Shears Attachment
A hydraulic shears attachment is fitted to a hydraulic excavator. A shearing device of
this kind is much larger and considerably more powerful than the hand shears for
reinforcing steel. Because of its great weight, it is suitable only for mechanized
actuation and movement from one working position to another. This device has two
blades, but these move longitudinally in relation to each other. In this case, the
shears are mounted on the excavator's hydraulic system that supplies the power, and
a cylinder is fed with the necessary hydraulic oil under pressure from the hydraulic
system.
Hydraulic Shearing Frame
A hydraulic shearing frame has blades in a frame-shaped mounting. One blade is
fixed and the other moves parallel to the fixed blade. Two cylinders accommodated in
the frame power the blade movement, and a hydraulic excavator or a separate
hydraulic power unit supplies the necessary oil under pressure. Because of its
considerable weight, a mechanical means is needed to handle or move the shearing
frame from one working position to another.
Safety Requirements and Controlling Hazards
• No special safety measures other than compliance with the generally
applicable safety requirements is required when working with the tools
and equipment for this technique.
• The hydraulic shears attachment can operate at a considerable height
above ground level. When the demolished material dislodged by the
shears falls to the ground, appropriate precautions must be taken. In
such cases the driver's cab should be protected against falling material.
Wire Rope & Hardware
Steel wire ropes can be attached in demolition work to pull down structural members,
but the force applied must never exceed the permissible load for the rope. This
technique is virtually unrestricted based on the height of, or the distance from, the
member to be demolished.
There are various ways of applying the pull to the rope: using independent winches,
using the winches of draglines, or by traction. For example, the rope may be passed
through a double or triple pulley block to increase the pulling force. The arm of a
hydraulic excavator can also provide the required force on the rope. The advantage of
this arrangement is that the machine operates at a suitable distance from the
member to be demolished.
Wrecking Balls
Balls generally are made of cast steel and generally weigh not more than 5,000
kilograms. The suspension point of a ball is almost always made of steel. A steel chain
is often used as the first part of the suspension. The ball may be spherical,
rectangular, pear-shaped, or cylindrical. The advantage of the pear shape is that it
cannot roll away when dropped vertically. Cylindrical balls are often made of steel.
Types of Balls
There are three types of guided balls available: pestle balls guided by a tube;
cylindrical balls guided by a tube; and an arrow drop ram, a rectangular ball with two
U-shaped guides. The arrow drop ram is a fully automatic balling machine designed to
demolish horizontal objects such as roads, runways, floors and carriageways. It is
mounted on a driven chassis with four wheels and pneumatic tires. The rectangular
ball is suspended in two U-shaped guides. The entire suspension can be displaced
transversely across the width of the chassis. The automatic adjustments are the
height of fall, the number of blows and the speed at which the machine is displaced.
If required, the ball can be fitted with an impact tool in the form of a spike, knifeedge, or cylinder.
Auxiliary Machines
For demolition by balling, the auxiliary machine from which the ball is suspended
must permit the ball to perform two types of motion: free fall and a swinging or
ballistic motion.
The choice of auxiliary machine depends on the:
• Object to be demolished
• Direction of impact (horizontal or vertical)
• Size of ball required
• Distances involved, including the height
The most common auxiliary machine is the dragline. For demolition purposes it is
equipped with free-fall winches. This machine can drop the weight vertically, impart a
swinging motion to it in the longitudinal direction of the arm via the pulling cable,
and, by moving the arm sideways, impart an oscillatory motion perpendicular to the
arm.
Safety Requirements and Controlling Hazards
• To comply with safety requirements, the distance between the dragline
and the structures to be demolished must equal at least half of the
structure's height and must always be at least six meters high. It is
important to maintain the dragline stability. This rule does not apply to
balling horizontal structures such as roads, foundations, floors, etc., as
the dragline is often situated on the structure itself.
• If the demolition work is carried out above the level of the base of the
dragline, or if the work is being done with a swinging ball, the size of the
ball should preferably not exceed 50 percent of the permitted load of the
dragline at the operational jib length and span of the dragline.
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Balling produces vibrations. The extent of the vibrations depends on the
object to be shattered, the soil, and the ball range used. Every time an
object is to be demolished, check to ensure that the vibrations that arise
are permissible.
The demolition operator can minimize the vibrations by:
o Adjusting the ball
o Adjusting the speed of impact
o Adopting a suitable size of collapse
Isolating the portion of the object to be demolished can localize the
vibrations by separating the portion of the structure to be retained from
the portion to be demolished. Isolating an object can also considerably
reduce transmission of vibrations to neighboring objects. If the
demolition leads the structure to collapse, this may also produce
vibrations as the materials fall.
The impact itself does not create a lot of dust. Large or small amounts of
material falling during balling may create a lot or just a little dust,
depending upon the object. Cleaning or wetting the object beforehand
and keeping it wet during demolition work can minimize dust formation.
Clothing and Dress Tips
A large part of demolition safety involves wearing proper clothing and using
appropriate safety accessories, especially when using power tools. These guidelines
can help provide safe demolition:
• Do not wear loose clothing that can get caught in machinery.
• Pull back long hair and secure it. Remove any jewelry that can interfere with
safe machinery operation.
• Wear safety goggles or glasses with side protection.
• Use a facemask in dusty applications and earplugs when the site is especially
noisy or for extended periods of work.
• Wear heavy work gloves to protect against the steady vibration of power tools
and the heat that can be generated, especially in the bit.
• Wear steel-toed shoes or boots.
Topic Summary
Please take a moment to review these major points before you continue with the next
topic.
PPE safety precautions for working with demolition equipment include:
• Not wearing loose clothing that can get caught in machinery
• Pulling back long hair to secure it and removing any jewelry that can interfere
with safe machinery operation
• Wearing safety goggles or glasses with side protection
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Using a facemask in dusty applications and earplugs when the site is especially
noisy or for extended periods of work
Wearing heavy work gloves to protect against the steady vibration of power
tools and the heat that can be generated, especially in the bit
Wearing steel-toed shoes or boots
OSHA standards require:
Operating cranes only if you have been trained in safe operating procedures
and the OSHA safety requirements
Participating in all crane safety programs offered by your employer or labor
organization
Knowing the location and voltage of all overhead power lines at the job site
before operating or working with any crane
Assuming that all power lines are energized and maintaining the minimum
clearance required by OSHA at all times
Power line standards require:
At least ten feet for lines rated 50 kilovolts or below
At least ten feet plus 0.4 inch for each kilovolt above 50 kilovolts (or
maintaining twice the length of the line insulator, but never less than ten feet)
Cranes must comply with noise regulations that may include noise-suppressors
fitted with silencers.
Use mats when necessary to provide support for machines on soft ground.
When employing cranes with outriggers, take care to ensure that the
outriggers cannot sink into the ground during load handling.
The force applied by steel wire ropes attached to structural members to be
demolished must never exceed the permissible load for the rope.
Topic 4: Special Structures Demolition
This topic reviews procedures for ensuring safety when demolishing various types of
special structures such as towers, pre-stressed concrete construction, and confined
spaces. Upon completing this topic, you will be able to:
• Describe safe practices for demolishing special structures
• Explain the hazards in special structure demolition
Safe Work Practices
When planning demolition of special structures such as chimney stacks, silos, and
cooling towers, these guidelines should be followed:
• Carry out hand demolition from a working platform.
• During scaffold erection, a competent person should be present at all times.
• Install portable walkways to provide access to the top of scaffolds.
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Deck platforms solidly and bridge the area with a minimum of two-inch-thick
lumber from the work platform to the wall.
Install a back rail 42 inches above the platform with a midrail covered with
canvas or mesh around the perimeter of the platform to prevent injury to
workers below. Debris netting below the platform may also be installed.
When working on the platform, all personnel should wear hard hats, longsleeve shirts, eye and face protection (such as goggles and face shields),
respirators, and safety belts, as required.
Assign the proper number of workers to the task. Too many people on a small
work platform can lead to incidents.
An alternative to erecting a self-supporting tubular steel scaffold is to "climb"
the structure with a creeping bracket scaffold. A competent person should
carefully inspect the masonry and decide the safety of the climbing alternative.
Do not work in inclement weather conditions such as lightning or high wind.
Wet down the worksite, as needed, to control dust.
Safety When Demolishing Tower-Like Structures
When preparing to demolish any chimney, stack, silo, or cooling tower, the first step
must be a careful, detailed inspection of the structure by an experienced person. If
possible, architectural/engineering drawings should be consulted. Pay particular
attention to the condition of the chimney or stack. Workers should identify any
structural defects such as weak or acid-laden mortar joints and any cracks or
openings. The interior brickwork in some sections of industrial chimney shafts can be
extremely weak.
Follow these additional guidelines before demolition activities begin:
• If the stack has been banded with steel straps, remove these bands as the
work progresses from the top down.
• Consider sectioning the chimney by water.
• Chimney masonry must be in good enough condition to support the bracket
scaffold.
• Experienced personnel must install a self-supporting tubular scaffold,
suspended platform, or knee-braced scaffolding around the chimney. Pay
particular attention to the design, support, and tie-in (braces) of the scaffold.
• Adequate working clearance between the chimney and the work platform is
essential.
• Rope off, barricade, and secure the area around the chimney and post
appropriate warning signs. No unauthorized entry should be permitted to this
area. As a good practice, keep a supervisor, operating engineer, another
worker, or a "safety person" on the ground with communication capabilities to
the workers above.
• Pay special attention to weather conditions when working on a chimney.
Clearing Debris
Debris disposal guidelines should be considered when working in special structure
demolition.
• Do not allow excessive debris to accumulate inside or outside the chimney
shaft. Excess weight of the debris can impose pressure on the structure and
cause the shaft to collapse.
• The foreman should determine when debris is to be removed, halt all
demolition during debris removal, and make sure the area is clear of cleanup
workers before continuing demolition.
• Remove debris dropped inside the shaft through an opening in the chimney at
grade level.
• Keep the opening at grade relatively small so the structure is not weakened. If
a larger opening is desired, consult a professional engineer.
• Provide an overhead canopy of adequate strength when removing debris by
hand. If employing machines to remove debris, use proper overhead protection
for the operator.
Deliberate Collapse Demolition
Another method of demolishing a chimney or stack is to cause a deliberate collapse.
Deliberate collapse requires extensive planning and experienced personnel, and
should be used only when conditions are favorable.
Using explosives is one way of setting off deliberate collapse. Only qualified persons
should undertake this type of demolition. The entire work area should be cleared of
nonessential personnel before placing any explosives. Although the use of explosives
is a convenient method for bringing down a chimney or stack, there is a considerable
amount of vibration produced, and caution should be taken if there is any likelihood
of damage.
Requirements for deliberate collapse include:
• Providing a clear space for the fall of the structure of at least 45 degrees on
each side of the intended fall line and 11/2 times the total height of the
chimney
• Verifying that no sewers or underground services are on the line of the fall
because of the considerable vibration that may occur when the chimney falls
• Posting required lookouts and arranging for mandatory warning signals on the
site -- keep the public and other workers at the job site well back from the fall
area
Prestressed Concrete Structures Demolition
Different forms of construction used to build conventional structures during the last
few decades present a variety of problems when they are demolished. Prestressed
concrete structures fall in this general category. Before demolishing a prestressed
concrete structure, an engineering survey must be completed to determine if the
structure to be demolished contains any prestressed members.
If so, the demolition contractor must inform and instruct all workers on the demolition
job site of the:
• Presence of prestressed concrete members
• Work practice to perform the demolition safely
• Hazards of deviating from the prescribed procedures
• Importance of following their supervisor's instruction
Categories of Prestressed Construction
There are four main categories of prestressed construction. These categories should
be determined before attempting demolition, bearing in mind that any prestressed
structure may contain elements of more than one category.
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Category 1 contains members prestressed before the application of the
superimposed loads, and all cables or tendons are fully bonded in the concrete
or grouted within ducts.
Category 2 contains members like those in Category 1, but the tendons are left
ungrouted. This type of construction can sometimes be recognized from the
access points provided for inspection of the cables and anchors. More recently,
unbonded tendons were used in the construction of beams, slabs, and other
members. These tendons are protected by grease and surrounded by plastic
sheathing instead of the usual metal duct.
Category 3 members are prestressed progressively as building construction
proceeds, and the dead load increases using bonded tendons as in Category 1.
Category 4 members are like Category 3 but use unbonded tendons as in
Category 2.
Examples of construction using members of Categories 3 or 4 are relatively rare.
However, they may be found in places like the podium of a tall building or some types
of bridges and require particular care in demolition.
Pretensioned Members
Pretensioned members have wires embedded or bonded within the length of the
member and usually do not have any end anchors. Simple pretensioned beams and
slabs of spans up to about seven meters (23 feet) can be demolished in a manner
similar to ordinary reinforced concrete.
Pretensioned beams and slabs may be lifted and lowered to the ground as complete
units after removing any composite concrete covering to the tops and ends of the
units. To facilitate breaking up, members should be turned on their sides. Generally,
lifting from the structure should be done from points near the ends of the units or
from lifting point positions. Reusing lifting eyes, if in good condition, is recommended
whenever possible. When units are too large to be removed, consider temporary
supporting arrangements.
Precast Units Stressed Separately
In the demolition of any of the following prestressed structures, a professional
engineer experienced in prestressed work should be consulted prior to the start of
any demolition.
Before breaking up precast units stressed separately, lower units of this type to the
ground, if possible. This work is hazardous especially where there are ungrouted
tendons because, in general, grouting is not always 100 percent efficient.
After lowering, the units can be turned on their sides with the ends up on blocks after
any composite concrete is removed. This may be sufficient to break the unit and
release the prestress.
If not, erect a sandbag screen, timbers, or a blast mat as a screen around the ends.
Clear the area of any personnel before demolition commences. Remember, the end
blocks may be heavily reinforced and difficult to break up.
Monolithic Structures
Before attempting to expose any tendons or anchorages of structures with two or
more members stressed together on a single tower, seek the advice of a professional
engineer experienced in prestressed work. It is usually necessary to provide
temporary supports so the tendons and anchorage can be cautiously exposed.
In these circumstances it is essential not to make any indiscriminate attempts to
expose and destress the tendons and anchorages.
Progressively Prestressed Structures
With progressively prestressed structures, the structure must be demolished in strict
accordance with the engineer's method of demolition. The stored energy in this type
of structure is large. In some cases, the inherent properties of the stressed section
may delay failure for some time, but sudden and complete collapse with little warning
may occur because of the presence of these large prestressing forces.
Safe Work Practices In Confined Spaces
Demolition contractors often come in contact with confined spaces when demolishing
structures at industrial sites. These confined spaces generally can be categorized into
two major groups:
• Those with open tops and a depth that restricts the natural movement of air
• Enclosed spaces with very limited openings for entry
Examples of these spaces include storage tanks, vessels, degreasers, pits, vaults,
casings, and silos.
The hazards encountered when entering and working in confined spaces are capable
of causing bodily injury, illness, and death. Incidents occur among workers because of
failure to recognize that a confined space is a potential hazard.
Therefore, whenever such spaces are involved, consider that the most unfavorable
situation exists in every case and that the danger of explosion, poisoning, and
asphyxiation can be present at the onset of entry.
Topic Summary
Please take a moment to review these major points before you continue with the next
topic.
• Requirements for deliberate collapse include providing adequate space, posting
lookouts and using warning signals to protect workers and others, and verifying
that no sewers or underground services are on the line of the fall because of
the considerable vibration that may occur when the chimney falls.
• The foreman should determine when debris is to be removed, halt all
demolition during debris removal, and make sure the area is clear of cleanup
workers before continuing demolition.
• Remove debris dropped inside the shaft through an opening in the chimney at
grade level.
• Excess weight of the debris might cause a shaft to collapse.
• If the stack has been banded with steel straps, remove these bands as the
work progresses from the top down.
• Pay special attention to weather conditions when working on a chimney.
Topic 5: Safe Blasting Procedures
This topic introduces safe blasting procedures in demolition.
Upon completing this topic, you will be able to:
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Explain the fire precautions required near explosives
Define the measures to ensure vehicle safety when transporting explosives
Describe required record maintenance for stored explosives
Describe safety precautions for use and follow-up after blasting
Blasting Survey and Site Preparation
Prior to blasting any structure or part of a structure, a complete written survey must
be made by a qualified person of all adjacent improvements and underground
utilities. When there is a possibility of excessive vibration from blasting operations,
seismic or vibration tests should determine proper safety limits to prevent damage to
adjacent or nearby buildings, utilities, or other property.
Preparing a structure for demolition by explosives may require removing structural
columns, beams, or other building components. A structural engineer or a competent
person qualified to direct the removal of these structural elements should direct this
work. Extreme caution must be taken during this preparatory work to prevent the
weakening and premature collapse of the structure.
Using explosives to demolish smokestacks, silos, cooling towers, or similar structures
should be permitted only if either:
• There is a minimum of 90 feet of open space extended for at least 150 percent
of the height of the structure
• The explosives specialist can demonstrate consistent previous performance
with tighter constraints at the site
Personnel Selection
A blaster is a competent person who uses explosives. A blaster must be qualified by
training, knowledge, or experience in the field of transporting, storing, handling, and
using explosives. In addition, the blaster should have a working knowledge of state
and local regulations that pertain to explosives. Training courses are often available
from manufacturers of explosives. The Institute of Makers of Explosives (IME) and
other organizations offer blasting safety manuals.
Blasters are required to furnish satisfactory evidence of competency in handling
explosives and in safely performing the type of blasting required. A competent person
should always be in charge of explosives and should be held responsible for enforcing
all recommended safety precautions in connection with them.
Fire Precautions
The presence of fire near explosives presents a severe danger!
Every effort should be made to ensure that fires or sparks do not occur near explosive
materials.
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Smoking, matches, firearms, open flame lamps, and other fires, flames, or
heat-producing devices must be prohibited in or near explosive magazines or in
areas where explosives are being handled, transported, or used.
Persons working near explosives should not even carry matches, lighters, or
other sources of sparks or flame.
Open fires or flames should be prohibited within 100 feet of any explosive
materials.
If there is a fire in imminent danger of contact with explosives, all employees
must be removed to a safe area.
Radio frequency (RF) signal sources should be restricted from or near the
demolition site if electrical detonators are used. Electrical detonators can be
triggered inadvertently by stray RF signals from two-way radios.
Transportation of Explosives
Vehicles used for transporting explosives should be in good mechanical condition and
should be strong enough to carry the load without difficulty. All vehicles used to
transport explosives should have tight floors. Any exposed spark-producing metal on
the inside of the body should be covered with wood or some other non-sparking
material. Vehicles or conveyances transporting explosives should be driven by and
supervised by only a licensed driver familiar with the local, state, and federal
regulations governing the transportation of explosives. No passengers should be
allowed in any vehicle transporting explosives.
Additional specifications regarding handling of explosives include the following:
1. Do not transport explosives, blasting agents, and blasting supplies with other
materials or cargo.
2. Do not transport blasting caps in the same vehicle with other explosives.
3. If an open-bodied truck is used, completely cover the entire load with a fireand water-resistant tarpaulin to protect it from the elements.
4. Vehicles carrying explosives should not be loaded beyond the manufacturer's
safe capacity rating, and in no case should explosives be piled higher than the
closed sides and ends of the body.
5. Mark or placard with warning signs required by OSHA and the Department of
Transportation (DOT) every motor vehicle or conveyance used for transporting
explosives.
6. Equip each vehicle used for transportation of explosives minimally with at least
a 10-pound rated, serviceable ABC fire extinguisher.
7. Train all drivers in using extinguishers on their vehicles.
8. Avoid congested traffic and high-density population areas where possible when
transporting explosives and make no unnecessary stops.
9. Do not take any vehicle carrying explosives, blasting agents, or blasting
supplies inside a garage or shop for repairs or servicing.
10.Never leave a motor vehicle transporting explosives unattended.
Inventory Maintenance and Safe Handling
All explosives must be accounted for at all times, and all not being used must be kept
in a locked magazine. A complete detailed inventory of all explosives received, placed
in, removed from, and returned to the magazine should be maintained at all times.
Appropriate authorities must be notified of any loss, theft, or unauthorized entry into
a magazine.
Manufacturers' instructions for safe handling and storage of explosives are ordinarily
enclosed in each case of explosives. Refer to these instructions and the Institute of
Makers of Explosives (IME) manuals to learn the specifics of storage and handling.
Follow these instructions carefully.
Safe Handling
• Do not handle any package of explosives roughly.
• Do not use sparking metal tools to open wooden cases.
• You may use metal slitters for opening fiberboard cases, provided the slitter
does not come in contact with the metallic fasteners of the case.
• Always use the oldest stock first to minimize the chance of deterioration from
long storage.
• Because of the hazards involved, segregate and properly dispose of any loose
explosives or broken, defective, or leaking packages according to the specific
manufacturer's instructions.
• If the explosives are in good condition, it may be advisable to repack them. In
this case, contact the explosives supplier. Explosives cases should not be
opened or explosives packed or repacked while in a magazine.
Storage Conditions
Providing a dry, well-ventilated place for the storage of explosives is one of the most
important and effective safety measures. Exposure to weather damages most kinds of
explosives, especially dynamite and caps. Every precaution should be taken to keep
them dry and relatively cool. Dampness or excess humidity may cause misfires,
resulting in injury or loss of life. Explosives should be stored in properly constructed
fire- and bullet-resistant structures, located according to the IME American Table of
Distances Explosives should not be left, kept, or stored where children, unauthorized
persons, or animals have access to them, nor should they be stored in or near a
residence. Detonators should be stored in a separate magazine located according to
the IME American Table of Distances.
DETONATORS SHOULD NEVER BE STORED IN THE SAME MAGAZINE WITH ANY
OTHER KIND OF EXPLOSIVES
Ideally, make arrangements to have the supplier deliver a single day's supply of
explosives to the job site so that they will be used during the workday. Alternatively,
ask the supplier to return to pick up unused explosives. If it is necessary for the
contractor to store his explosives, he should be familiar with all local requirements for
such storage.
Proper Use of Explosives
Blasting operations should be conducted between sunup and sundown, whenever
possible. Adequate warning should be sounded to alert everyone in the area to the
hazard presented by blasting. Blasting mats or other containment should be used
where there is danger of rocks or other debris being thrown into the air or where
there are buildings or transportation systems nearby. Use care to make sure mats
and other protection materials do not disturb the connections to electrical blasting
caps.
Radio, television, and radar transmitters create fields of electrical energy that can,
under exceptional circumstances, detonate electric blasting caps. Certain precautions
must be taken to prevent incidental discharge of electric blasting caps from current
induced by radar, radio transmitters, lightning, adjacent power lines, dust storms, or
other sources of extraneous or static electricity.
Click here to see additional precautions.
These precautions should include:
• Ensuring that mobile radio transmitters on the job site that are less than 100
feet away from electric blasting caps, in other than original containers, are deenergized and effectively locked
• Prominently displaying adequate signs warning against the use of mobile radio
transmitters on all roads within 1,000 feet of the blasting operations
• Maintaining the minimum distances recommended by the IME between the
nearest transmitter and electric blasting caps
• Suspending all blasting operations and removing people from the blasting area
during the approach and progress of an electric storm
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Adopting standard signals to indicate that a blast is about to be fired and to
indicate a later all-clear signal -- it is important that everyone working in the
area be familiar with these signals and that they be strictly obeyed
After loading of explosives is completed, there should be as little delay as
possible before firing.
The blaster should directly supervise each blast fired.
The blaster should inspect all connections before firing and personally see that
all persons are in the clear before giving the order to fire.
Inspection and Disposal Procedures
Immediately after the blast has been fired:
• Disconnect and short-circuit the firing line from the blasting machine.
• Where power switches are used, they must be locked in the off position. Allow
sufficient time for dust, smoke, and fumes to leave the blasted area before
returning to the spot.
• The blaster should inspect the area and the surrounding rubble to determine if
all charges have been exploded before employees are allowed to return to the
operation.
• The blaster should trace all wires and search for unexploded cartridges.
Disposal of Explosives
• Do not use explosives, blasting agents, and blasting supplies that are obviously
deteriorated or damaged; they should be disposed of properly. Explosives
distributors will usually accept returns of old stock. Local fire marshals or
representatives of the United States Bureau of Mines may also arrange for
disposal of explosives.
• Do not abandon any explosives under any circumstances!
• Wood, paper, fiber, or other materials that have contained high explosives
should not be used again for any purpose. They should be burned at an
isolated outdoor location at a safe distance from thoroughfares, magazines,
and other structures. These materials should not be burned in a stove,
fireplace, or other confined space.
• It is important to check that the containers are entirely empty before burning.
During burning, the area should be protected adequately from intruders and all
persons kept at least 100 feet from the fire.
Topic Summary
Please take a moment to review these major points before you continue with the next
topic.
• A complete blasting survey by a qualified person of all adjacent improvements
and underground utilities is required, and if excessive vibration is possible,
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tests should be made to determine safety limits to prevent damage to nearby
property.
Use explosives to demolish tower-like structures only if there is a minimum of
90 feet of open space for at least 150 percent of the height of the structure or
the explosives specialist can demonstrate consistent previous performance with
tighter constraints at the site.
A blaster must be qualified in the field of transporting, storing, handling, and
using explosives as well as be familiar with state and local explosives
regulations.
Every effort should be made to ensure that fires and sparks do not occur near
explosive materials.
Vehicles for transporting explosives must carry at least a ten-pound-rated
serviceable ABC fire extinguisher, and drivers must be trained in its use.
Never leave a motor vehicle transporting explosives unattended.
Rotate explosives in stock to minimize deterioration.
Any loose, broken, defective, or leaking packages of explosives should be
segregated and disposed of according to manufacturer's instructions because of
the hazards involved.
Providing a dry, well-ventilated place for storing explosives is one of the most
important and effective safety measures.
Blasting should be suspended during the approach and progress of an electrical
storm, and all people should be removed from the area.
Signs warning against the use of mobile radio transmitters should be posted on
all roads within 1,000 feet of blasting operations.
Standard signals should be established to indicate before the start of blasting
and when blasting is completed, and personnel in the area should be familiar
with these signals.
Lesson Summary
This lesson contained information and instruction about demolition. By completing
this lesson, you should have the knowledge to discuss the following topics. Take a
moment to see if you can do the following:
• Define the need for a survey prior to beginning any demolition job
• List particular areas of structures that are regulated by OSHA requirements
when demolition is being done
• Describe demolition equipment used to bring down structures without
explosives
• List some of the hazards that exist in special structures demolition
• Discuss safe blasting procedures and the hazards that exist on worksites
• You can use the left navigation menu to go to any topic to study it again, or
you can go to the topic summary pages directly to review the key points.
Blasting
Introduction
This lesson will enhance your safety, knowledge, and skills regarding blasting
operations and help you communicate responsible behavior to other workers, who will
be directly affected by your activities. Upon completing this lesson, you will be able
to:
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Identify the importance of the role of the blasting agent and comply with
general blasting safety provisions on the job site
Implement an efficient planning strategy and an effecting blasting operation
Minimize blasting hazards and deploy safeguards for special blasting
circumstances
Why Learn This Lesson?
Of all the professions on earth, none demands a stricter commitment to safety,
proper training, and product education than that of the explosive engineer.
Those who place and detonate explosives have a great responsibility to conduct
themselves professionally. They must give the utmost consideration to the awesome
effect of explosives on life and property. That responsibility extends to themselves,
their customers, their fellow workers, and the general public.
In an occupation where blasting operations are performed, it is important to strive
continually to upgrade your professional skills and competence through education and
training. This lesson will make you more aware of the accepted safety standards and
proper blasting practices. You should carry these practices with you wherever you
may travel and be as professional and safety conscious as you possibly can in the
performance of your work.
Topic 1: General Provisions
This topic covers the proper training and qualifications for those engaged in blasting,
as well as safety practices involving the storage, handling, and transportation of
explosives. Upon completing this topic, you will be able to:
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List six safe blasting practices
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Identify the qualifications of explosive engineers
Exercise safety precautions for working around explosives
Apply safeguards for storing, handling, and transporting explosives
Use the American Table of Distances for the storage of explosives
Safety First
Blasting is inherently a dangerous activity. SAFETY MUST ALWAYS COME FIRST!
Never compromise safety for any reason. There are several keys to safe blasting
practices:
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Ongoing training for both new and experienced personnel
Correct procedures for the storage, transportation, loading, and detonation of
explosives that are consistently followed and frequently audited
Correct explosive product selection and use
Defining responsibility for the blast (blaster-in-charge)
Careful analysis of blast site conditions
Paying attention to details
General Safety Areas
With the hazards that are presented by blasting operations, there must be a strict
commitment to safety in these general areas.
Blaster Qualifications
In order to be qualified as a blaster, the individual must be:
• Able to understand and give written and oral orders
• In good physical condition and not be addicted to narcotics, intoxicants, or
similar types of drugs
• Qualified, by reason of training, knowledge, or experience, in the field of
transporting, storing, handling, and use of explosives, and have a working
knowledge of state and local laws and regulations that pertain to explosives
• Required to furnish satisfactory evidence of competency in handling explosives
and safely performing the type of blasting that will be required
• Knowledgeable and competent in the use of each type of blasting method used
Working Around Explosives
Only authorized and qualified persons are permitted to handle and use explosives,
and no person under the influence of intoxicating liquors, narcotics, or other
dangerous drugs is to handle or use explosives.
The following are prohibited in or near explosive magazines or while explosives are
being handled, transported, or used:
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Smoking
Other fires
Firearms
Flame or heat-producing devices
Matches
Sparks
Open flame lamps
The original containers, or Class II magazines, must be used to take detonators and
other explosives from the storage magazines to the blasting area.
Security
Explosives are extremely dangerous, and therefore, all explosives must be accounted
for at all times. The following requirements must be met:
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Keep unused explosives in a locked magazine so that they are unavailable to
any workers not authorized to handle them.
Document an inventory and record of use for all explosives.
There must be procedures in place to notify the appropriate authorities in the
event of any loss, theft, or unauthorized entry into a magazine.
Attend to explosives or blasting agents at all times and never abandon them.
Fire and Emergency Preparedness
You should not fight a fire where the fire is in imminent danger of contact with
explosives. In the event of a fire, all employees have to be removed to a safe area
and the fire area guarded against intruders.
Explosive Handling
Explosives need to be transported and stored with strict safety concerns in mind.
Click each image below to learn its handling requirements.
Surface Transportation of Explosives
Specific safety requirements apply to transportation of explosives by motor vehicle.
The following requirements are mandated by OSHA:
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A licensed driver who is physically fit and familiar with the local, state, and
federal regulations governing the transportation of explosives can transport
explosives by motor vehicles or conveyances.
Smoking is absolutely prohibited, and no person will even be permitted to carry
matches or any other flame-producing device while in or near a motor vehicle
or conveyance transporting explosives. The carrying of firearms or loaded
cartridges is also prohibited.
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Transporting vehicles must be rated for load factors, be in good mechanical
condition, and never be left unattended.
No other cargo or blasting caps can be transported on a vehicle with explosive
materials, and the car cannot to be taken inside a garage or shop for repairs or
servicing while the explosives are on board.
If the vehicle has an open body, a Class II magazine or original manufacturer's
container must be mounted securely on the bed to contain the cargo. The
vehicle must also be marked or placarded on both sides, the front, and the rear
with the word "Explosives" in red letters, not less than four inches in height, on
a white background.
A fully charged fire extinguisher must be on board the vehicle with a rating of
at least 10-ABC, and the driver must be trained in its use.
Underground Transportation of Explosives:
Whenever explosives or blasting agents are transported underground, they
must be taken to the place of use or storage without delay, and the following
safety requirements apply:
Take only the required quantity of explosives or blasting agents to any
underground loading area.
No one except the operator, his helper, and the powderman is permitted to ride
on a transport carrying explosives and blasting agents.
Check the truck's electrical system weekly. It is prohibited to install auxiliary
lights on truck beds that are powered by the truck's electrical system.
Explosives and blasting agents must be hoisted, lowered, or conveyed in a
powder car, and no other materials, supplies, or equipment are to be
transported at the same time. The car or conveyance containing explosives or
blasting agents should be pulled, not pushed, and it must bear a reflectorized
sign on each side with the word "Explosives" in letters not less than four inches
in height upon a background of sharply contrasting color.
If they are being transported in a shaft, then the hoist operator must be
notified prior to their being moved, and the explosives must never be left
unattended.
Detonators and other explosives are not to be transported at the same time in
any shaft conveyance, and explosives, blasting agents, or blasting supplies
cannot be transported with other materials.
Storage of Explosives and Blasting Agents
In order to maintain the maximum degree of safety, explosives and all related
materials have to be stored in approved facilities. When storing explosives, the
following requirements apply:
Blasting caps, electric blasting caps, detonating primers, and primed cartridges
must not be stored in the same magazine with other explosives or blasting
agents.
Smoking and open flames are not permitted within 50 feet of explosives and
the detonator storage magazine.
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No explosives or blasting agents can be permanently stored in any
underground operation until the operation has been developed to the point
where at least two modes of exit have been provided.
Permanent underground storage magazines must be at least 300 feet from any
shaft or active underground working area, and those containing detonators
cannot be located closer than 50 feet to any magazine containing other
explosives or blasting agents.
American Table of Distances
Use the American Table of Distance to determine the safe distance between
magazines to store explosives. There are three points to consider.
1. Applies to the manufacture and permanent storage of commercial explosive
materials. The distances specified are those measured from the explosive
materials storage facility to the inhabited building, highway, or passenger
railway, irrespective of property lines.
2. Covers all commercial explosive materials, including, but not limited to, high
explosives, blasting agents, detonators, initiating systems, and explosive
materials in process. The table is not designed to be altered or adjusted to
accommodate varying explosive characteristics such as blast effect, weight
strength, density, bulk strength, detonation velocity, etc.
3. Provides a guide for developing distances for the unconfined, open burning of
waste explosive materials where the probability of transition from burning to
high-order detonation is improbable. It should not be used to determine safe
distances for blasting work, the firing of explosive charges for testing or quality
control work, or the open detonation of waste explosive materials.
Topic Summary
Please take a moment to review these major points before you continue with the next
topic.
• In order to be qualified as a blaster, an individual must be able to communicate
orders, be in good physical condition, and be competent in blasting
methodology.
• Explosives are extremely dangerous, and safeguard policies for work activities,
security systems, and fire preparedness must be followed.
• Explosives are transported by motor vehicles and there are specific safety
requirements for their storage and handling.
Topic 2: Planning and Operating
Overview
When conducting blasting operations, workers must always keep safety in mind.
Construction activities often take place in areas that affect other operations. Planning
must occur to minimize personal and property risks. This topic introduces safety
planning and operating strategies. Upon completing this topic, you will be able to:
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Formulate a planning strategy for preventing accidental discharge, handling
explosives, securing areas and monitoring explosive shelf lives, and placing
detonators
Implement procedures for loading explosives safely and efficiently
Identify provisions for initiating electric and non-electric charges
General Safety Provisions
The blaster must take special precautions in the loading, delaying, initiation, and
confinement of each blast with mats or other methods to control the throw of
fragments and thus prevent bodily injury to employees.
Employees authorized to prepare explosive charges or conduct blasting operations
must use every reasonable precaution to ensure employee safety, including:
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Visible and audible warning signals
Flags
Barricades
Whenever possible, blasting operations above ground must be conducted during
daylight hours between sunup and sundown.
Preventing Accidental Discharge
Precautions have to be taken to prevent the accidental discharge of electric blasting
caps from current induced by radar, radio transmitters, lightning, adjacent power
lines, dust storms, or other sources of extraneous electricity. These precautions
include:
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Short-circuit detonators in holes that have been primed and shunted until wired
into the blasting circuit.
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Suspend all blasting operations and remove persons from the blasting area
during the approach and progress of an electric storm.
De-energize and effectively lock radio transmitters that are less than 100 feet
from electric blasting caps.
Display signs warning against the use of mobile radio transmitters on all roads
within 1,000 feet of blasting operations.
Handling Explosives
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All empty boxes, paper, and fiber packing materials that previously contained
high explosives are not to be used again for any purpose and must be
destroyed by burning at an approved location.
Explosives, blasting agents, and blasting supplies that are obviously
deteriorated or damaged are not to be used.
Delivery and issue of explosives is to be made by and to only authorized
persons and into authorized magazines or approved temporary storage or
handling areas. All loading and firing must be directed and supervised by a
competent person.
All blasts must be fired electrically with an electric blasting machine or properly
designed electric power source.
The use of black powder is prohibited.
Blasting Areas
Blasting operations in the proximity of overhead power lines, communication lines,
utility services, or other services and structures must not be conducted until the
operators and/or owners have been notified and measures for safe control have been
taken.
Buildings that are to be used for the mixing of blasting agents or water gels must be
made of noncombustible construction or sheet metal on wood studs. Floors in a
mixing plant are to be made of concrete or other nonabsorbent materials.
In areas where fuel oil is used, all fuel oil storage facilities must be separated from
the mixing plant and located so that, in the event of tank rupture, the oil will drain
away from the mixing plant building. Also:
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The building must be well ventilated.
Heating units that do not depend on combustion processes can be used in the
building. All direct sources of heat must be provided exclusively from units
located outside the mixing building.
All internal combustion engines used for electric power generation must be located
outside the mixing plant building or be properly ventilated and isolated by a firewall.
The exhaust systems on these engines must be located so that any spark emission
would not be a hazard to any materials in or adjacent to the plant.
Shelf Life of Explosive Materials
Explosive manufacturers want their products to function at full efficiency; therefore,
they advise distributors and/or consumers regarding the shelf life of the products and
make recommendations as to proper use and application.
Store explosive materials so that corresponding grades, brands, sizes and "DatePlant-Shift" codes are together, and rotate stocks so the oldest material in the
magazine is used first.
NOTE: Consult with the manufacturer to assure that accepted practices for the
use and storage of explosive materials are being followed.
Detonator and Booster Placement
Surface blasts are initiated electronically, depending upon local conditions and
operating requirements. Whichever system is employed, plan the delay sequence for
each blast before loading starts to ensure proper relief and control. Otherwise, fly
rock, excessive throw, cutoffs, and misfires may occur. Errors are most apt to happen
when:
• A large number of holes are being blasted
• The blast consists of multirows
• There are several crews loading the blast
• The blast pattern is irregular
• A combination of delay systems (electronic detonators, sequential blasting
machine, shock tube/delay primers, etc.) is being deployed
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To ensure that the designed delay pattern is being followed, the blaster-in-charge
normally "lays out" the pattern by placing the initiators and/or delay devices at the
collar of the hole prior to loading. This eliminates any possibility of the loading crews
selecting the wrong initiator or delay and allows the blaster-in-charge to effectively
monitor the loading operation.
Blasting Loading Procedures
Before loading starts, safe and efficient procedures for loading explosives are carried
out.
Drill and Check the Holes
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All drill holes must be sufficiently large to freely admit the insertion of the
cartridges of explosives.
Drilling must not be started until all remaining butts of old holes are examined
for unexploded charges, and if any are found, they must be refired before work
proceeds.
No person must be allowed to deepen drill holes that have contained explosives
or blasting agents.
Drill holes which have been sprung or chambered and which are not waterfilled must be allowed to cool before explosives are loaded.
Holes
Tamping must be done only with wood rods or plastic tamping poles without
exposed metal parts; however, nonsparking metal connectors may be used for
jointed poles. Violent tamping must be avoided, and the primer must never be
tamped.
No holes must be loaded except those that are to be fired in the next round of
blasting. After loading, all remaining explosives and detonators must be
returned to an authorized magazine immediately.
Holes must be checked prior to loading to determine depth and conditions.
Where a hole has been loaded with explosives but the explosives have failed to
detonate, there must be no drilling within 50 feet of the hole.
When loading a long line of holes with more than one loading crew, the crews
must be separated by practical distance consistent with efficient operation and
supervision of crews.
All blast holes in open work must be stemmed to the collar or to a point that
will confine the charge.
A borehole must never be sprung when it is adjacent to or near a hole that is
loaded. Flashlight batteries must not be used for springing holes.
No loaded holes must be left unattended or unprotected.
Equipment
• Machines and all tools not used for loading explosives into boreholes must be
removed from the immediate location of holes before explosives are delivered.
Equipment must not be operated within 50 feet of loaded holes.
• When loading blasting agents pneumatically over electric blasting caps,
semiconductive delivery hose must be used, and the equipment must be
bonded and grounded.
• Powerlines and portable electric cables for equipment being used must be kept
a safe distance from explosives or blasting agents being loaded into drill holes.
Cables in the proximity of the blast area must be deenergized and locked out
by the blaster.
The Blasting Area
• No activity of any nature other than that which is required for loading holes
with explosives must be permitted in a blast area.
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No explosive must be loaded or used underground in the presence of
combustible gases or combustible dusts.
No explosives or blasting agents must be left unattended at the blast site.
Warning signs indicating a blast area must be maintained at all approaches to
the blast area.
Electric Blasting
When initiating electric charges for electric blasting, care must be given to various
general provisions, underground operations, and blasting machines.
General Provisions
• Electric blasting caps must not be used where sources of extraneous electricity
make the use of electric blasting caps dangerous. Blasting cap leg wires must
be kept short-circuited (shunted) until they are connected into the circuit for
firing.
• Before adopting any system of electrical firing, the blaster must conduct a
thorough survey for extraneous currents, and all dangerous currents must be
eliminated before any holes are loaded.
• In any single blast using electric blasting caps, all caps must be of the same
style or function and of the same manufacture.
• Electric blasting must be carried out by using blasting circuits or power circuits
in accordance with the electric blasting cap manufacturer's recommendations
or with the approved contractor or his or her designated representative.
• When firing a circuit of electric blasting caps, care must be exercised to ensure
that an adequate quantity of delivered current is available in accordance with
the manufacturer's recommendations.
• Connecting wires and lead wires must be insulated, single solid wires of
sufficient current-carrying capacity.
• Bus wires must be solid single wires of sufficient current-carrying capacity.
• When firing electrically, the insulation on all firing lines must be adequate and
in good condition.
• A power circuit used for firing electric blasting caps must not be grounded.
Underground Operations
• In underground operations when firing from a power circuit, a safety switch
must be placed in the permanent firing line at intervals. This switch must be
made so it can be locked only in the "Off" position and must be provided with a
short-circuiting arrangement of the firing lines to the cap circuit.
• In underground operations, there must be a "lightning" gap of at least five feet
in the firing system ahead of the main firing switch; that is, between this
switch and the source of power. This gap must be bridged by a flexible jumper
cord just before firing the blast.
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When firing from a power circuit, the firing switch must be locked in the open
or "Off" position at all times, except when firing. It must be so designed that
the firing lines to the cap circuit are automatically short-circuited when the
switch is in the "Off" position. Keys to this switch must be entrusted only to the
blaster.
Blasting Machines
• Blasting machines must be in good condition, and the efficiency of the machine
must be tested periodically to make certain that it can deliver power at its
rated capacity.
• When firing with blasting machines, the connections must be made as
recommended by the manufacturer of the electric blasting caps used.
• The number of electric blasting caps connected to a blasting machine must
exceed its rated capacity. Furthermore, in primary blasting, a series circuit
must contain no more caps than the limits recommended by the manufacturer
of the electric blasting caps in use.
• The blaster must be in charge of the blasting machines, and no other person
must connect the leading wires to the machine.
• Blasting galvanometers are equipped with a silver chloride cell especially
designed for this purpose.
• Whenever the possibility exists that a leading line or blasting wire might be
thrown over a live power line by the force of an explosion, care must be taken
to see that the total length of wires is kept too short to hit the lines, or that the
wires are securely anchored to the ground. If neither of these requirements can
be satisfied, a non-electric system must be used.
• In electrical firing, only the person making leading wire connections must fire
the shot. All connections must be made from the borehole back to the source
of firing current, and the leading wires must remain shorted and not be
connected to the blasting machine or other source of current until the charge is
to be fired.
• After firing an electric blast from a blasting machine, the leading wires must be
disconnected from the machine immediately and short-circuited.
Non-Electric Blasting
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The selection and design of the initiation system should be under the
supervision of the blaster-in-charge.
The initiation system hookup must be used in accordance with the
maufacturer's recommendation.
The blaster-in-charge must conduct a visual check after blast hookup.
When using a system that can be checked for continuity, the blast layout must
be tested for continuity as recommended by the manufacturer.
Where judged necessary by the blaster-in-charge, a double trunkline or closedloop hookup must be used
When not using electrical charges to ignite the blast, the blasting system is comprised
of fuses, detonators, firing, and the final inspection. Click each system component to
learn about its safety processes.
Use of safety fuse
A safety fuse must be used only where sources of extraneous electricity make the use
of electric blasting caps dangerous. When a safety fuse is being used, the following
requirements must be followed:
• Use of a fuse that has been hammered or injured in any way must be
forbidden.
• The hanging of a fuse on nails or other projections which will cause a sharp
bend to be formed in the fuse is prohibited.
• Before capping a safety fuse, a short length must be cut from the end of the
supply reel to assure a fresh cut-end in each blasting cap.
• Only a cap crimper of approved design must be used for attaching blasting
caps to safety fuse. Crimpers must be kept in good repair and accessible for
use.
• No unused cap or short capped fuse must be placed in any hole to be blasted;
such unused detonators must be removed from the working place and
destroyed.
• No fuse must be capped, or primers made up, in any magazine or near any
possible source of ignition.
• No one must be permitted to carry detonators or primers of any kind on his
person.
• The minimum length of safety fuse to be used in blasting must be as required
by state law, but must not be less than 30 inches.
• At least two men must be present when multiple cap and fuse blasting is done
by hand lighting methods.
• Not more than 12 fuses must be lighted by each blaster when hand lighting
devices are used. However, when two or more safety fuses in a group are
lighted as one by means of igniter cord or other similar fuse-lighting devices,
they may be considered as one fuse.
• The so-called "drop fuse" method of dropping or pushing a primer or any
explosive with a lighted fuse attached is forbidden.
• Cap and fuse must not be used for firing mudcap charges unless charges are
separated sufficiently to prevent one charge from dislodging other shots in the
blast.
When blasting with safety fuses, consideration must be given to the length and
burning rate of the fuse. Sufficient time, with a margin of safety, must always be
provided for the blaster to reach a place of safety.
Use of Detonating Cord
Care must be taken to select a detonating cord consistent with the type and physical
condition of the borehole and stemming and the type of explosives used, and the
detonating cord must be handled and used with the same respect and care given
other explosives. The following requirements must be followed:
• The line of detonating cord extending out of a borehole or from a charge must
be cut from the supply spool before loading the remainder of the borehole or
placing additional charges.
• Detonating cord must be handled and used with care to avoid damaging or
severing the cord during and after loading and hooking up.
• Detonating cord connections must be competent and positive in accordance
with approved and recommended methods. Knot-type or other cord-to-cord
connections must be made only with detonating cord in which the explosive
core is dry.
• All detonating cord trunklines and branchlines must be free of loops, sharp
kinks, or angles that direct the cord back toward the oncoming line of
detonation.
• All detonating cord connections must be inspected before firing the blast.
• When detonating cord millisecond-delay connectors or short-interval-delay
electric blasting caps are used with detonating cord, the practice must conform
strictly to the manufacturer's recommendations.
• When connecting a blasting cap or an electric blasting cap to detonating cord,
the cap must be taped or otherwise attached securely along the side or the end
of the detonating cord, with the end of the cap containing the explosive charge
pointed in the direction in which the detonation is to proceed.
• Detonators for firing the trunk-line must not be brought to the loading area nor
attached to the detonating cord until everything else is in readiness for the
blast.
Firing the Blast
A code of blasting signals must be posted on one or more conspicuous places at the
operation, and all employees must familiarize themselves with suitable locations.
WARNING SIGNAL - A 1-minute series of long blasts 5 minutes prior to blast signal.
BLAST SIGNAL - A series of short blasts 1 minute prior to blast shot.
ALL CLEAR SIGNAL - A prolonged blast following the inspection of blast area.
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Before a blast is fired, a loud warning signal must be given by the blaster in
charge, who has made certain that all surplus explosives and all employees are
in a safe place and all employees, vehicles, and equipment are at a safe
distance or under sufficient cover.
Flagmen must be stationed safely on highways that pass through the danger
zone to stop traffic during blasting operations.
It must be the duty of the blaster to fix the time of blasting.
Before firing an underground blast, warning must be given, and all possible
entries into the blasting area, and any entrances to any working place where a
drift, raise, or other opening is about to hole through, must be carefully
guarded. The blaster must make sure that all employees are out of the blast
area before firing a blast.
Inspection After Blasting
Immediately after the blast has been fired, the firing line must be disconnected from
the blasting machine or, where power switches are used, they must be locked open or
in the off position.
Sufficient time (not less than 15 minutes in tunnels) must be allowed for the smoke
and fumes to leave the blasted area before returning to the shot. An inspection of the
area and the surrounding rubble must be made by the blaster (and, in tunnels, the
muck pile wetted down) to determine if all charges have been exploded before
employees are allowed to return to the operation.
Topic Summary
Please take a moment to review these key points before you continue with the next
topic.
• Formulate a planning strategy for preventing accidental discharge, handling
explosives, securing areas and monitoring explosive shelf lives, and placing
detonators.
• Safe and efficient explosive loading procedures are mandated for holes,
equipment, and areas.
• Provisions for initiating electric blasting include general, underground, and
machinery.
• Selection of a non-electric initiation system includes considering the fuse,
detonating cord, firing, and inspection.
Topic 3: Hazards and Special Circumstances
Overview
This topic makes you aware of blasting hazards and focuses on two special blasting
circumstances. Upon completing this topic, you will be able to:
• Identify hazards related to misfires, fumes, and underground and outdoor
blasting
• Identify special precautions required for underwater blasting and blasting in
excavation work under compressed air
Blasting Hazards
You have been presented with the precautions for safe blasting; however, blasting is
still a very dangerous activity.
Misfires
Misfires must be handled under the direction of the person in charge of the blasting.
If a misfire is found, the blaster must first provide proper safeguards for excluding all
nonessential employees from the danger zone then remove the hazard without before
starting any new work.
No attempt must be made to extract explosives from any charged or misfired hole; a
new primer must be put in and the hole re-blasted. If refiring of the misfired hole
presents a hazard, the explosives may be removed by washing out with water or,
where the misfire is under water, blown out with air.
If there are any misfires while using cap and fuse, all employees must remain away
from the charge for at least 1 hour. All wires must be carefully traced and a search
made for unexploded charges. In addition, no drilling, digging, or picking must be
permitted until all missed holes have been detonated or the authorized representative
has approved that work can proceed.
Fumes From Blasting Operations
Blasting operations produce toxic and nontoxic gases as a normal byproduct,
regardless of the types of explosive materials used. Normally, prevailing winds or air
currents readily dilute and dissipate to the atmosphere any gases generated in openpit blasting or outdoor construction blasting.
Underground Blasting
Special efforts, such as using low fume-producing products and providing fresh air
ventilation, minimize exposure to gases generated by underground blasting.
For underground blasting operations, explosive materials with Fume Class 1, 2, or 3
ratings can be ordered from an explosive supplier. Fume Class 1 explosives are
recommended for use in poorly ventilated areas such as dead headings and blindraises. Explosives complying with the requirements of Fume Class 2 and Fume Class 3
may be used if adequate ventilation has been provided.
No explosives other than those rated in Fume Class 1, 2, or 3 should be used
underground.
Outdoor Blasting
Blasters should be aware that under certain blasting or geologic conditions, gases
may migrate and collect in the basements of adjacent buildings or in nearby
underground locations such as manholes, sumps, or tunnels. Where necessary,
monitoring and/or venting practices to detect and eliminate entrapped gases should
be employed.
To minimize any hazardous exposure from the gases produced by outdoor blasting, it
is essential that the blaster:
1. Be aware that lack of ground displacement may prevent venting of the
blasted material and result in the entrapment of gases
2. Excavate blasted material as soon as possible after blasting
Excavation should start as close to the underground-enclosed space as possible
in order to provide for venting of any entrapped gases.
Additionally, it is recommended that the blaster:
1. Be aware of and look for geologic pathways for carbon monoxide (CO), such
as old trenches, horizontal partings, faults, joints, hillseams, unconsolidated
material, water, and voids that would allow movement of gas toward
underground-enclosed spaces.
2. Enclosed spaces and fractures caused by the detonation may create a
pathway for the gases.
3. Conduct a preblast survey to determine any possible problem areas when
blasting near inhabited buildings or underground facilities (tunnels, manholes,
etc.).
4. Monitor possible problem areas to determine if any gases have migrated
from the blasting operation. If gases are detected, use adequate and positive
ventilation.
5. Keep accurate and complete records of all blasts.
Drilling monitoring holes between the blasting operation and the inhabited building or
other area of concern can detect the movement of CO from the blast site. However,
these monitoring holes, even on close spacing, may not intersect the geologic
pathway and therefore may not allow detection of CO. These holes will not provide
adequate passive venting of migrating gases. If located too close to the blast, these
holes actually may create a hazard by allowing blast gases to rifle up them and create
flyrock.
One technique has removed migrated CO from the ground successfully and quickly.
This technique involved applying negative pressure to the earth and removing the CO
from the ground surrounding the underground-enclosed space. Even rudimentary
systems, involving placing a fan on top of a vertically buried large-diameter pipe with
holes drilled in the side, have worked.
Special Circumstances
Two types of blasting have there own unique requirements: blasting underwater and
using comprised air.
Underwater Blasting
A blaster must conduct all blasting operations, and no shot must be fired without his
approval.
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Loading tubes and casings of dissimilar metals must not be used because of
possible electric transient currents from galvanic action of the metals and
water.
Only water-resistant blasting caps and detonating cords must be used for all
marine blasting. Loading must be done through a non-sparking metal loading
tube when a tube is necessary.
No blast must be fired while any vessel underway is closer than 1,500 feet to
the blasting area. Those on board vessels or craft moored or anchored within
1,500 feet must be notified before a blast is fired.
No blast must be fired while any swimming or diving operations are in progress
in the vicinity of the blasting area. If such operations are in progress, signals
and arrangements must be agreed upon to ensure that no blast is fired while
any person is in the water.
Blasting flags must be displayed.
The storage and handling of explosives aboard vessels used in underwater
blasting operations must be according to provisions outlined herein on handling
and storing explosives.
When more than one charge is placed underwater, a float device must be
attached to an element of each charge in such a manner that it will be released
by the firing. Misfires must be handled in accordance with the requirements of
§1926.911.
Underground Blasting
• Detonators and explosives must not be stored or kept in tunnels, shafts, or
caissons. Detonators and explosives for each round must be taken directly from
the magazines to the blasting zone and loaded immediately. Detonators and
explosives left over after loading a round must be removed from the working
chamber before the connecting wires are connected.
• When detonators or explosives are brought into an airlock, no employee except
the powderman, blaster, lock tender, and the employees necessary for carrying
must be permitted to enter the air lock. No other material, supplies, or
equipment must be locked through with the explosives.
• Detonators and explosives must be taken separately into pressure working
chambers.
• The blaster or powderman must be responsible for the receipt, unloading,
storage, and on-site transportation of explosives and detonators.
• All metal pipes, rails, airlocks, and steel tunnel lining must be electrically
bonded and grounded at or near the portal or shaft and cross-bonded at not
less than 1,000-foot intervals throughout the length of the tunnel. In addition,
each low air supply pipe must be grounded at its delivery end.
• The explosives suitable for use in wet holes must be water-resistant and must
be Fume Class 1.
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When tunnel excavation in rock face is approaching mixed face, and when
tunnel excavation is in mixed face, blasting must be performed with light
charges and with light burden on each hole. Advance drilling must be
performed as tunnel excavation in rock face approaches mixed face to
determine the general nature and extent of rock cover and the remaining
distance ahead to soft ground as excavation advances.
Topic Summary
Please take a moment to review these key points before you continue with the next
topic.
• Misfires, fumes, and underground and outdoor blasting must be managed not
to cause hazards.
• Special safety efforts are required for underwater and excavation blasting.
Lesson Summary
This lesson contained information and instruction about blasting operations. By
completing this lesson, you should have the knowledge to discuss the following
topics. Take a moment to see if you can do the following:
• Identify the importance of the role of the blasting agent and comply with
general blasting safety provisions on the job site
• Implement an efficient planning strategy and an effecting blasting operation
• Minimize blasting hazards and deploy safeguards for special blasting
circumstances
Stairways and Ladders
Introduction
Many construction workers have probably thought, "Ladders and stairways are
so easy to use that there is no way people could get hurt using them."
Guess what? Stairways and ladders are a major source of injuries and
fatalities among construction workers. OSHA estimates that there are nearly
25,000 injuries and as many as 36 fatalities per year due to falls from
stairways and ladders used in construction. Nearly half of all of the injuries are
serious enough to require time off the job. When a fall occurs, the person who
falls usually gets hurt. In addition, others working around the ladders may also
be injured.
It is because abuse and misuse of ladders in the workplace is the rule rather
than the exception. Practically all falls from ladders can be traced to using
them in an unsafe manner.
So, what should you do to prevent injuries?
You must observe ladder safety rules for your own and other people's safety.
OSHA requires that safe equipment be furnished for use. However, it is the
responsibility of the user to use the safe equipment safely. Following the
correct safety procedures and complying with OSHA's requirements for the
safe use of ladders and stairways can prevent many of the injuries and
fatalities that occur each year.
Lesson Overview
In this lesson, you will learn about the OSHA regulations and training
requirements for stairways and ladders, the hazards associated with stairways
and ladders, and their safe use. You also will learn more about different types
of ladders and their safe use, care, and maintenance.
Upon completing this lesson, you will be able to:
• Describe the four general OSHA requirements for using stairways and
ladders
• Discuss the safe use of stairways
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Define the different types of ladders, including portable ladders vs. fixed
ladders, straight ladders vs. stepladders, and single ladders vs.
extension ladders
Discuss the safe use of portable ladders including straight ladders,
stepladders, and extension ladders
Summarize the proper care and inspection of ladders
Why Learn This Lesson?
Falls are a leading cause of death on the construction site. The incidents
include slipping on wet or icy surfaces, falling down stairs, falling off the roof,
and falling from ladders. In fact, more than 30,000 people are injured each
year by falls involving ladders.
A fall from a ladder can kill. It can disable a person for the rest of his or her
life. Or it can injure him so severely that his earning power is cut off for a long
time. None of these is a happy prospect.
Most stairways and ladder incidents are the result of careless or improper use.
They occur because the victims violate the basic rules of stairway and ladder
safety. This lesson will assist the learner with an overview of the Occupational
Safety & Health Administration (OSHA) standards for stairways and OSHA and
American National Standards Institute (ANSI) standards for ladders.
The lesson will offer tips for proper stairway and ladder usage on and off the
job. It also contains information that serves as a quick and easy reference for
employers and employees on the requirements of the OSHA regulations and
some common rules for the safe use of stairways and ladders.
Some of the hazards are:
• Loss of balance
• Slippery surface
• Overreaching
• Carelessness
• Reckless climbing
• Carrying equipment while climbing
• Electrical shock
• Unprotected bases
• Ladder not secured
• Falling objects
Topic 1: General Information
The use of differing methods to access a higher or lower level has been around
since the beginning of man. Over time, these means and methods have
developed into our current stairway and ladder systems.
Stairways and ladders are two of the most easy-to-use tools in the
construction industry. However, they are often misused or used in a careless
manner and, therefore, cause many injuries. This topic addresses the
coverage of OSHA standards on stairways and ladders, the general
requirements of using stairways and ladders, OSHA's training requirements,
and Turner's policy on using stairways and ladders. Upon completing this
topic, you should be able to:
• List the four general requirements for using stairways and ladders
• Describe OSHA training requirements
Coverage of OSHA Standards
OSHA's construction safety and health standards apply to all stairways and
ladders used in construction, alteration, repair (including painting and
decorating), and demolition operations. They also specify when stairways and
ladders must be provided.
The standards do not apply to ladders that are manufactured specifically for
scaffold access and egress. However, they do apply to job-made and
manufactured portable ladders intended for general purpose use which are
then used for scaffold access and egress.
General Requirements
The following are general OSHA requirements for using stairways and ladders:
• A stairway or ladder must be provided at all points of access where there
is a break in elevation of 19 inches (48 cm) or more, and no ramp,
runway, embankment, or personnel hoist is provided.
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When there is only one point of access between levels, it must be kept
clear to permit free passage by workers. If free passage becomes
restricted, a second point of access must be provided and used.
When there are more than two points of access between levels, at least
one point of access must be kept clear.
All stairway and ladder fall protection systems must be installed and all
duties required by the stairway and ladder rules must be performed
before employees begin to use stairways, ladders, and their respective
fall protection systems.
Training Requirements
Under OSHA provisions, employers must provide a training program to
employees on using stairways and ladders.
The training must enable each employee to recognize hazards related to
stairways and ladders and to use proper procedures to minimize them. This
training must be conducted by a competent person.
Employers must ensure that each employee is trained in the following areas,
as applicable:
• The nature of fall hazards in the work area
• The correct procedures for erecting, maintaining, and disassembling the
fall protection systems to be used
• The proper construction, use, placement, and care in handling of all
stairways and ladders
• The maximum intended load-carrying capacities of ladders used
In addition, retraining must be provided for each employee, as necessary, so
that the employee maintains the understanding and knowledge acquired.
Information From Suppliers
Before purchasing or putting into use stairway or ladder systems, employers
should obtain information about the systems from the supplier.
Not all systems may need to be individually tested. The performance of some
systems may be based on data and calculations derived from testing of similar
systems, provided that enough information is available to demonstrate
similarity of function and design.
Employers should obtain comprehensive instructions from the supplier as to
the system's proper use and application, including, where applicable:
• The force measured during the sample force test
• Caution statements on critical use limitations
• Application limits
• Methods of inspection, use, cleaning, and storage
Topic Summary
Please take a moment to review these major points before you continue with
the next topic.
• OSHA's construction safety and health standards apply to almost all
stairways and ladders used in construction.
• A stairway or ladder must be provided at all points of access where there
is a break in elevation of 19 inches (48 cm) or more, and no ramp,
runway, embankment, or personnel hoist is provided.
• All stairway and ladder fall protection systems required by OSHA
standards must be installed, and all duties required by the standards
must be performed before employees begin to use stairways, ladders,
and their respective fall protection systems.
• Under OSHA provisions, employers must provide a training program to
employees on using stairways and ladders. The training must enable
each employee to recognize hazards related to stairways and ladders,
and to use proper procedures to minimize them. A competent person
must conduct this training.
• Before purchasing or putting into use stairway or ladder systems,
employers should obtain comprehensive instructions from the supplier as
to the system's proper use and application.
Topic 2: Stairway Safety
Stairways, both permanent parts of the structure and those for temporary use,
are a common means of access to other elevations on the construction site.
This topic addresses safe stairway use in detail. Upon completing this topic,
you should be able to:
• Restate four general requirements of using stairways taught in this topic.
• List eight requirements for stair rails and handrails taught in this topic.
General Requirements
There are some general requirements that apply to all stairways used during
the process of construction.
Landings
If a stairway is not going to be a part of the permanent structure on which the
construction work is being performed, it must have landings every 12 feet of
rise or less. These landings must be at least 30 inches deep and 22 inches
wide.
Angle of Inclination
Stairways must be installed at least 30 degrees and no more than 50 degrees
from the horizontal.
Variations in Riser Height
Variations in riser height or stair tread depth must not exceed 1/4 inch in any
stairway system, including any foundation structure used as one or more
treads of the stairs.
Platform Near Doors or Gates
A platform must be provided wherever there are doors or gates that open
directly onto a stairway. The platform must extend at least 20 inches beyond
the swing of the door.
Others
• Metal pan landings and metal pan treads must be secured in place
before filling.
• All stairway parts must be free of dangerous projections such as
protruding nails.
• Slippery conditions on stairways must be corrected.
Temporary-Stairway Requirements
There are three main requirements that apply to stairs in temporary service
during construction.
• Except during construction of the actual stairway, stairways with metal
pan landings and treads must not be used where the treads and/or
landings have not been filled in with concrete or other material, unless
the pans of the stairs and/or landings are temporarily filled in with wood
or other material. All treads and landings must be replaced when worn
below the top edge of the pan.
• Except during construction of the actual stairway, skeleton metal frame
structures and steps must n