COURSE NAME: Industrial Safety and Hazards Mitigation (3-0-0)
COURSE CODE: (CH257) (3-0-0) (3 Credits)
For B.Tech II Yr II Semester
Prerequisites subjects: CRE, TD, PDPE
COURSE OBJECTIVE:
To introduce the basic concepts of safety precaution to be taken in
in the workplace of the chemical plant. Safety precautions are
taken for accidental fire, explosion etc. Students are also required
to learn the various hazard control and mitigation methods.
COURSE OUTCOME:
Students could able to identify the hazards substance, and the
preventive measures. Also can able to identify the best methods
for prevention of fire explosion.
Types of chemical plants
Bulk chemical
Fine chemical
Specialty chemical
Ex. Ethylene, Acetone,
Sulfuric acid, Nitrogen,
Oxygen etc.
Ex. Dimethyl formamide,
N-butyric acid,
Chloropropylene etc.
Ex. Pesticides, Perfumes,
Pharmaceutical, flavoring
Production: large volume,
High investment, normal
Operating cost
Production: Small volume
Low investment,
low operational cost
Production: Low volume
Low investment,
low operational cost
3
Control: Keep the flammable material in a close chamber to avoid air contact. Insulate
the chamber as much as possible.
Types of Fire
Class A
( burning
ordinary solid)
Class B
(Burning
Liquid and gas)
Class C
Class D
(Consume metal)
(They burn
class A and
Class B in presence
of live electric circuit)
4
Syllabus
Introduction and Industrial hygiene: Safety programs, Engineering ethics, Accident and loss Statistics,
Acceptable risk, Public perceptions, Nature of the accident process, Inherent safety, Anticipation and
identification, Hygiene evaluation and control.
Fires and Explosions and concepts to prevent fires and explosions: Fire triangle, Distinction
between fires and explosions, Flammability characteristics of liquids and vapors, Limiting oxygen
concentration and inerting, Flammability diagram, Inerting, Controlling static electricity, Explosionproof equipment and instruments, Ventilation, Sprinkler systems.
Introduction to reliefs: Relief concepts, location of reliefs, relief types, relief scenarios, Data for sizing
reliefs, relief systems.
Hazards Identification: Process hazards checklists, Hazards surveys, Hazards and Operability studies,
safety reviews.
Safety procedures and designs: Process safety Hierarchy, Managing safety, Best practices,
procedures- operating, Procedures-permits, Procedures- safety reviews and accident investigations,
Designs for process safety.
Text Books:
1. Chemical process safety (Fundamentals with Applications) D.A.Crowl and J.F
Louvar, Prentice Hall, 2013, 3rd Edition.
Reference Books:
1. Chemical Engineering, Volume 6, John Metcalf Coulson, John Francis
Richardson, R.K.SinnottButterwoth-Heinemann 1999.
2. Safety in the process Industries, Rulph king, Butterworth-Heinemann, 1990.
Method of Evaluation
ClassTest – 1 / Surprise test
10 Marks
Class Test – 2 / Assignment /
Surprise test
10 Marks
Mid-Semester Examination
20 Marks
Class Test - 3 / Assignment /
Seminar
10 Marks
ClassTest – 4 / Assignment /
Surprise test
10 Marks
End Semester Examination
40 Marks
Total
100 Marks
Introduction and Industrial hygiene
Safety programs, Engineering ethics, Accident and loss Statistics, Acceptable
risk, Public perceptions, Nature of the accident process, Inherent safety,
Anticipation and identification, Hygiene evaluation and control.
What is safety Programs
Specific training
Survey
Safety Programs
Training
Implementation
Why safety program?
 Reduces accidental injuries and health illness in the work place
 Reduce compensation cost of the company due to injuries
 Eliminate or control hazard in timely manner
 Improve productivity of the worker
 Create healthy environment in the work place
Engineering ethics
The word “Ethics” originates from the Greek word “ethos” meaning “character”. Ethics
are a set of rules or principles that are generally considered as standards or good and bad
or right and wrong, which are usually imposed by an external group or a society or a
profession or so.
The study of related questions about moral ideals, character, policies and relationships of
people and organizations involved in technological activity, can be termed as Engineering
ethics.
The ethical decisions and moral values of an engineer need to be
considered because the decisions of an engineer have an impact
the products and services
 Respecting others and ourselves.
 Respecting the rights of others.
 Avoiding unnecessary problems to others.
 Avoiding cheating and dishonesty.
 Showing gratitude towards others and encourage them to work.
Accident and loss Statistics
Bhopal gas tragedy was a chemical accident on the night of 2–3 December 1984 at the
Union Carbide India Limited (UCIL) pesticide plant in Bhopal, Madhya Pradesh, India.
574,366: No of people injured
Aprox. 16000: Died within two weeks
Compensation: In 1989, UCC paid $470 million
to settle litigation stemming from the disaster.
UCC: CEO of the company: Anderson
In June 2010, seven Indian nationals who were UCIL employees in 1984,
including the former UCIL chairman, were convicted in Bhopal of causing death
by negligence and sentenced to two years imprisonment and a fine of about $2,000
each, the maximum punishment allowed by Indian law.
All were released on bail after two years and also died before the final judgement.
In 2001, the UCC was owned by DOW company and all the cases were closed.
Acceptable risk:
The term "acceptable risk" describes the likelihood of an event whose probability
of occurrence is small, whose consequences are so slight.
All the process are designed by the engineers, hence, they must make every
effort to minimize the risk within economic constraints.
Table: Three types of chemical plants accidents
Public perception:
 General public has great difficulty with the concept of acceptable risk
 The major objection is due to the involuntary nature of acceptable risk
 The chemical plant designer who specify the acceptable risk assume that
this risk are satisfactory to the civilian living near the plant.
 Most of the time these civilian are not aware about the risk.
Nature of the accident process:
 Chemical plant follow typical pattern
 It is important to study these pattern in order to anticipate the type of accident
that will occurs.
 Fire are most common followed by explosion and toxic released in the
chemical plant.
 With respect to the fatality, the toxic release having the greatest potential of
fatality
 Economic loss is consistently high for accidents involving explosions.
 The most damaging type of explosion is an unconfined vapor cloud explosion,
where a large cloud of volatile and flammable vapor is released and dispersed
throughout the plant site followed by ignition and explosion of the cloud
An analysis of largest chemical plant accident based on world wide accident is
shown below
 Toxic release typically results in little damage to capital equipment. Personnel
injuries, employee losses, legal compensation, and cleanup liabilities can be
significant.
 largest cause of loss in a chemical plant is due to mechanical failure. Failures
of this type are usually due to a problem with maintenance. Pumps, valves, and
control equipment will fail if not properly maintained.
 The second largest cause is operator error. For example, valves are not opened
or closed in the proper sequence.
 Human error is frequently used to describe a cause of losses. Almost all
accidents, except those caused by natural hazards, can be attributed to human
error. For instance, mechanical failures could be due to human error as a result
of improper maintenance or inspection.
Inherent safety:
 Inherently safer plants are tolerant of errors and are often the most cost
effective.
 A process that does not require complex safety interlocks and elaborate
procedures is simpler, easier to operate, and more reliable.
 Smaller equipment, operated at less severe temperatures and pressures, has
lower capital and operating costs
 In general, the safety of a process relies on multiple layers of protection. The
first layer of protection is the process design features. Subsequent layers
include control systems, interlocks, safety shutdown systems, protective
systems, alarms, and emergency response plans.
 Inherent safety is a part of all layers of protection; however, it is especially
directed toward process design features.
 An inherently safer plant is more tolerant of operator errors and abnormal
conditions.
 Although a process or plant can be modified to increase inherent safety at any time in
its life cycle, the potential for major improvements is the greatest at the earliest stages
of process development.
 At these early stages process engineers and chemists have the maximum degree of
freedom in the plant and process specifications, and they are free to consider basic
process alternatives, such as changes to the fundamental chemistry and technology.
 The major approach to inherently safer process designs is divided into the
following categories:
 intensification
 substitution
 attenuation
 limitation of effects
 simplification/error tolerance
Terms and definitions
Inherent safety technique:
The design of an inherently safe and simple piping system minimizing the use of sight
glasses, flexible connectors, and bellows, using welded pipes for flammable and toxic
chemicals. There are some accident occurred through out the globe, discussed below.
Flixborough, England
 It happened in England in the year 1974
 It was designed to produce caprolactam, basic raw material for nylon production
along with cyclohexane (similar to gasoline).
 There was a leakage in the reactor,
 Upon rupture of the bypass, an estimated 30 tons of cyclohexane volatilized and
formed a large vapor cloud
 28 people died and 36 got injured.
Seveso, Italy
 It is a small town in Italy. The plant was owned by the Icmesa Chemical Company.
 The product was hexachlorophene, a bactericide, with trichlorophenol produced as an
intermediate. During normal operation TCDD (2,3,7,8tetrachlorodibenzoparadioxin) is produces as the undesirable side-product .
 It is a toxic substance, small dose of 10⁻⁹ times the body weight can cause acne like
diseases and persist for long time.
 An estimated 2 kg of TCDD was released through a relief system in a white cloud
over Seveso. A subsequent heavy rain washed the TCDD into the soil. Approximately
10 square miles were contaminated. Nearly 2000 people were affected and 4 people
died.
Pasadena, Texas
 A massive explosion in Pasadena, Texas, on October 23, 1989, resulted in 23 fatalities,
314 injuries, and capital losses of over $715 million.
 This explosion occurred in a high-density polyethylene plant after the accidental
release of 85,000 pounds of a flammable mixture containing ethylene, isobutane,
hexane, and hydrogen.
 The release formed a large gas cloud instantaneously because the system was under
high pressure and temperature.
 The cloud was ignited about 2 minutes after the release by an unidentified ignition
source
Anticipation and identification
 When you anticipate hazards, you are taking a proactive approach to driving
instead of a reactive one where you simply wait until something attracts your
attention and demands your immediate action. In essence, you are predicting
the future and acting in. There are five ways to identify hazards.
 Collect existing information about workplace hazards.
 Inspect the workplace for safety and health hazards.
 Identify health-related hazards.
 Conduct incident investigations.
 Identify hazards associated with emergency situations.
Hygiene evaluation and control.
 Industrial hygiene has been defined as “that science and art devoted to the anticipation,
recognition, evaluation, and control of those environmental factors or stresses arising in
or from the workplace, which may cause sickness, impaired health and well-being, or
significant discomfort among workers or among the citizens of the community.”
 Industrial hygienists use environmental monitoring and analytical methods to detect the
extent of worker exposure and employ engineering, work practice controls, and other
methods to control potential health hazards
 Under the OSH Act, OSHA develops and sets mandatory occupational safety and health
requirements applicable to the more than 6 million workplaces in the U.S. OSHA relies
on, among many others, industrial hygienists to evaluate jobs for potential health
hazards.
 Developing
and
setting
mandatory
occupational
safety
and
health
standards
involves determining the extent of employee exposure to hazards and deciding what is
needed to control these hazards to protect workers.
 Industrial hygienists are trained to anticipate, recognize, evaluate, and recommend controls
for environmental and physical hazards that can affect the health and well-being of
workers.
 Industrial hygienists analyze, identify, and measure workplace hazards or stresses that
can cause sickness, impaired health, or significant discomfort in workers through
chemical, physical, ergonomic, or biological exposures.
 Two roles of the OSHA industrial hygienist are to spot those conditions and help eliminate
or control them through appropriate measures