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IND320 Safety for Engineers
Safety Engineering:
An Introduction
Prof. Dr. Salaheddine BENDAK
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Importance of Occupational Safety
ILO/WHO statistics reveal that:
• 2,780,000 people die annually due to work
related causes.
• 86.3% die due to occupational diseases and
13.7% die due to occupational accidents.
• Top three occupational diseases:
1. Circulatory diseases 31%
2. Malignant neoplasms 26%
3. Respiratory diseases 13%
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Texas City Refinery
Accident
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Piper Alpha Accident
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Deepwater Horizon Accident
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Sayano Sheshenskaya Accident
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Definitions
• Safety: Freedom from harm! (vs. accepting low
risk).
• Hazard: any condition which has the potential
to harm the health or cause damage.
• Risk: The probability that a hazard will actually
result in an accident.
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Where is Safety?
Is Safety a
Science ?!
Do we expect
Safety to be
black & white
at all times ?!
Is Money the
Solution for
All Our Safety
Problems ?!
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Selecting the Best Approach
Decision Making Is A Biased Shot In The Dark
 Behavior-Based Programs
 Comprehensive Ergonomics
 Engineering Changes
 Group Problem Solving
 Government Action
 Management Audits
 Stress Management
 Poster Campaigns
 Personnel Selection
 “Near-miss” reporting
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Selecting the Best Approach
◆Superimpose a safety
program on the
organization.
◆We need “built-in” safety,
or integrated safety, and
not some artificially
introduced program.
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Cost of Safety
➢Registers as a net cost
and not a net profit
➢Pay Now or Pay Later
✓Direct Costs of
Accidents
✓Indirect Costs
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Direct costs of accidents include:
• cost of lost wages of injured or killed workers
• compensation paid
• medical costs
• cost of fixing damaged equipment and machines
• others
Indirect costs of accidents include:
 cost of wages paid for workers who were not injured
 cost of overtime paid for workers to make up for lost
time
 increased insurance premiums
 Cost of decreased productivity due to the accident and
the low morale of workers
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 Others
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Cost-Benefit Trade-off
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Production and Safety
Management should strike a balance between
Successful
Management
Health & Safety
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IS SAFETY FIRST?
•
•
•
•
•
The slogan of the National Safety Council was:
“safety first.”
Today we realize that we really do not want “safety
first” any more than we want “safety last”
Both slogans mean that safety is being considered as
something separate from other aspects of operations.
Safety must be an integral part of operations.
We want Safe Operations.
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Reactive Approach
Event / Accident
What went wrong?
Fix it, Create rules to stop it
happening again
Wait for next time
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Proactive Approach
Policy
Organize
Monitor
Implement
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Common Terms in Injury Statistics
Lost Time Injuries (LTI's)
It is the number of injuries that resulted in work time loss.
Frequency Rate (FR)
It identifies the number of injuries experienced or expected in a
period where one million person hours of exposure occurs.
# of LTI's X 1,000,000
FR = -----------------------------------Total person hours worked
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Example 1) if we have
• 46 LTI's per year.
• 500 workers.
• 1.15 million hours worked in one year.
Find the Frequency Rate (FR)? Explain?
46 X 1,000,000
FR = ----------------------- = 40
1,150,000
This means that 40 LTl's occurred per million person
hours worked.
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Example 2) Find the person hours worked in the
following case:
• 40 hr/week.
• 50 weeks/year
• 100 workers
Total person hours worked per year =
40x50x100=200,000.
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Average Time Lost Rate ( ATLR )
This rate indicates the severity of injuries
# of days lost
ATLR = ------------------# of LTI's
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Example 3) lf we have the following case; find ATLR.
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500 workers.
46 LTI's per year
10 LTI's resulted in 3 days each
8 LTI's resulted in 6 days each
12 LTI's resulted in 14 days each
4 LTI's resulted in 20 days each
10 LTI's resulted in 28 days each
2 LTI's resulted in 42 days each
# of LTI's = 10+8+12+4+10+2 = 46
# of days lost = (I0x3)+(8x6) +(12xI4)+(4x20)+(I0x28)+(2x42) = 690 days.
690
ATLR = ------- = 15 days.
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Incidence Rate (IR)
This rate calculates, in percentage terms, the number
of LTI's experienced by the work group.
# of LTI's X 100
IR = -----------------------------# of workers exposed
From previous example:
46 X 100
IR = -------------- = 9.2 % per year.
500
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SOURCES OF ACCIDENTS
• People: Mgrs, Employees & Public – People plan,
design, build, operate and maintain the plant system!
• Equipment: Fixed plant, machines, tools, protective
gear & vehicles.
• Material: Crude liquid or gas, process substances,
supplies, products may have physical & chemical
hazards affecting people, equipment & environment
• Environment: Surroundings e.g. buildings, surfaces &
sub-surfaces, atmosphere, lighting, noise, radiation,
heat or cold weather & social or economic conditions
which can affect safe performance of people,
equipment and materials.
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CAUSES OF LOSSES
Domino Effect:
a. Loss: Injury – human sufferings and economic
aspects of loss costs & work delays or Property
Damage vary from Minor to Major. A loss is the effect
of an:
b. Incident: Undesired event could result in loss –
injury &/or property damage &/or production upset
(Contd. Next Slide)
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THE CAUSES OF LOSSES
c. Unsafe Acts & Conditions: Causes of Loss Incidents -
Substandard Practices:
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
Operating Equipment without authority
Failure to Warn
Failure to Secure
Operating at an Improper Speed
Making Safety Device Inoperable
Removing Safety Devices
Using Defective Equipment
Using Equipment Improperly
Failure to Use PPE
Improper Loading
Improper Placement
Improper Lifting
Improper Position for Task
Servicing Equipment in Operation
Horseplay
Under Influence of Drugs (Contd. Next Slide)
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THE CAUSES OF LOSSES
Common Substandard Conditions:
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
Inadequate Guards or Barriers
Inadequate or Improper Protective Equipment
Defective Tools, Equipment or Materials
Congestion or Restricted Movement
Inadequate Warning System
Fire & Explosion Hazards
Poor Housekeeping; disorder
Hazardous Environment: gases, dusts, smokes, fumes,
vapors, lack of oxygen
Noise Exposure
Vibration Exposure
Radiation Exposure
High or Low Temp. Exposure
Inadequate or Excess Illumination
Inadequate Ventilation (Contd. Next Slide)
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CAUSES OF LOSSES
Unsafe Conditions & Practices are the effects of:
d. Existence of Environmental & Personal Factors: Basic
indirect causes of losses e.g.:
Environmental Factors:
1.
Inadequate Design Standards
2.
Inadequate Purchasing Standards
3.
Inadequate Maintenance Standards
4.
Inadequate Work Standards
5.
Normal Wear & Tear
6.
Abnormal Use rate or Method
Personal Factors:
1.
Lack of Knowledge
2.
Lack of Skill or Proficiency
3.
Improper or Inadequate Motivation
4.
Physical incapacities
5.
Mental Incapacities
6.
Stress
(Contd. Next Slide)
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CAUSES OF LOSSES
Environmental or Personal Factors are the effects of:
e. Inadequate Management:
1.
Inadequate Loss Prevention Program: Program
does not include enough of the Principles &
Practices for the Risks
2.
Inadequate Program Standards: Standards are
vague or incomplete
3.
Inadequate Compliance with Standards: Lack of
employee education, compliance with requirements,
motivation & enforcement.
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CAUSES OF ACCIDENTS
Root causes by analysis of accident records:
1.
2.
3.
4.
5.
6.
7.
Design Failure
Operational Error
Equipment Failure
Maintenance & Inspection Deficiencies
Inadequate Supervision & Training
Natural Phenomena
External Influences
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Design Failure
• Operating conditions not adequately
foreseen – Temp & Pressure excursions
• Codes & Standards not followed
• Improper Metallurgy (welds etc)
• Lack of Emergency Shutdown/isolation (BP
Refinery - TX)
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OPERATIONAL ERROR
• Instructions not clear or not understood
• Misinterpretation of instrument readings
• Equipment inadequately marked/labeled
• Poor work environment – extreme weather
conditions, noise, access, housekeeping
• Anxiety or stress under abnormal situations
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EQUIPMENT FAILURE
• Defective manufacture or construction
• Engineering faults not detected
• Vibrations (Gas Plant Disaster)
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MAINTENANCE & INSPECTION DEFICIENCIES
• Inadequate or deferred equipment
e.g. tanks & pressure vessels,
corrosion rates
• Poor mechanical, instrument &
electrical maintenance (US Refineries)
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INADEQUATE SUPERVISION & TRAINING
• Failure to enforce procedures & regulations e.g. Work
Permits, Emergency Instrumentation
• Operating manuals & flow diagrams not maintained
• Lack conducting emergency simulated exercises
• Lack holding meaningful safety meetings
• Lack providing clear written instructions
• Lack providing refresher training
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SUMMARY - CAUSES OF ACCIDENTS
Nature of Cause
%
• Design, process or equipment failure
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• Maintenance & Inspection Deficiencies
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• Inadequate Supervision, Training
or Plant Operations
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• Natural Phenomena
or External influences
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100
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SUMMARY & CONCLUSIONS
• Unsafe acts do not ALWAYS cause an accident
• Many accidents result in NO injury or damage
• FEW accidents result in minor injury or damage
• Cannot tell WHICH unsafe act will cause a serious
injury or fatality
• Unsafe acts will EVENTUALLY result in a serious injury
Thank you!
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