1. IE 419
Work Design:
Productivity and Safety
Dr. Andris Freivalds
Class #21
IE 419 1
2. Basics of Accident Prevention
(Heinrich, Petersen, Roos – Industrial Accident Prevention)
• Accident Prevention – direct control of
workers, machines, environment to
prevent accidents
• Safety Management - long range
planning, education, training to prevent
accidents
IE 419 2
3. Accident Prevention Process
Identify Problem
Collect Data
Analyze Data
Select Remedy
Monitor
Apply Remedy
IE 419 3
8. 3 E’s of Accident Prevention
• Engineering – redesign of job/workplace
• Education – training
• Enforcement – discipline, rules
Accident Causation Models →
IE 419 8
9. Life Change Unit Theory
• Accident probability
is situational
• Overload taxes
person’s capacity
• Leads to accidents
(or illness)
• >300 → 79% in 2 yrs
• >200 → 51% in 2 yrs
• >150 → 37% in 2 yrs
Rank Life Event Units
1 Death of
spouse
IE 419 9
100
2 Divorce 73
4 Jail term 63
6 Injury 53
27 End school 26
41 Vacation 13
13. Job Safety Analysis (JSA)
(Job Hazard Analysis, Methods Safety Analysis,
Critical Incident Technique, Failure Mode and Effects
Analysis (FMEA), Hazard and Operability Study (HAZOP))
1) Break down job into elements
2) List them in sequential order
3) Examine them critically
4) Focus on:
• Worker
• Method
• Machine
• Material
IE 419 13
15. Ex. #2 - JSA
Scenario: Two inspectors smashed their toes
when a stack of armor plate (36x24x⅜ in),
standing on end against workbench, slid to the
floor. They were stacked there because of
insufficient room to leave them on delivery
pallet, towed from Receiving. Since each piece
needed to Rockwell tested, the inspectors
stacked the plates on end rather than laying
them flat on the floor, which would require later
lifting (NIOSH!!). Similar accidents had occurred
earlier, but without injuries.
Typical Solution:
IE 419 15
18. Advantages of JSA
• Maps out all details
• Quick, simple, objective
• Compares old & new methods
• Examines effects on production
• Analyze safety before accident occurs
• Leads into Fault Tree Analysis
IE 419 18
21. Value Engineering - Safety
• Define Factors:
– Effect on safety
– Cost
– Morale
– Social/environment
• Choose Alternatives – depends
• Determine Weights – judgmental
• Rate each alternative by factor - relative
• Resulting Value (sum of products) selects
proper alternative
IE 419 21
22. Risk Analysis – Basics
• Basic premise/approach
– All risks can not be eliminated
– However, can reduce potential loss
– Go for max cost effectiveness
• Risk of loss increases with:
– ↑ probability that hazard will occur
– ↑ exposure to the hazard
– ↑ consequences of hazardous event
IE 419 22
23. Risk Analysis - Procedure
• Assign numerical values to factors
• Multiply factors → overall risk score
• Risk score is a numerical value
• Good for relative comparison (not
absolute)
IE 419 23
29. Apply Remedy and Monitor
• Who applies remedy
– Safety specialist/engineer
– Line supervisors
– Workers
• Monitor effectiveness of
accident prevention
– Close the feedback loop
– Variety of statistical
approaches
Monitor
IE 419 29
Identify
Problem
Collect
Data
Analyze
Data
Select
Remedy
Apply
Remedy
30. Accident and Injury Statistics
• Incidence (frequency) rate
IR = # incidents x 200,000
# hrs exposure
• Severity rate
SR = # days lost x 200,000
# hrs exposure
IE 419 30
31. Chi-Square Analysis
• χ2 = Σ (Ei – Oi)2/ Ei Ei = HixOT/HT
• M = # areas Ei = expected
• Oi = observed OT = Total observed
• Hi = hours worked in area i
• HT = total hours worked ν = m -1
IE 419 31
32. Ex. #6 - Chi-Square Analysis
Dept. # CTD # Hours IR Ei
A 22 900,000
B 4 600,000 1.3 7.4
C 10 1,400,000 1.4 17.4
Total 36 2,900,000 2.5 36
χ2 = Σ (Ei – Oi)2/ Ei
IE 419 32
