1. ERT 312
LECTURE 2
Accident & Loss Statistics

2. Accident & Loss Statistics
A measure of the effectiveness of the safety programs
An indicator whether a process is safe or SOP is working correctly
Taken by average, thus not reflect for single events involving substantial losses

3. 3 ALS Systems: OSHA Incidence Rate Fatal Accident Rate (FAR)
Fatality Rate, or Death per Person per Year

4. OSHA Incidence Rate Based on cases/100 worker years
A standard worker year = 2000 hours
50 weeks/year x 40 hours/week
Therefore, OSHA IR is based on 200,000 hours of worker exposure to a hazard
100 worker years x 2000 hours

5. Injury and illness (Equation 1)
Lost workdays (Equation 2)
Number of lost workdays

6. Question 1.9 (Crowl & Louvar, 2002)
A university has 1200 full-time employees. In a particular year this university had 38 reportable lost-time injuries and 274 lost workdays. Compute the OSHA IR based on injuries and lost workdays. Assume an employee works for 8hr, 250 days/year

7. Answers: OSHA IR (Injury and Illness) = 3.17
OSHA IR (Lost workdays) = 22.83

8. FAR British chemical industry
Based on 1000 employees working their entire lifetime
Total working years/employee = 50 years
Therefore, FAR is based on 108 working hours

9. Equation 3

10. Question 1.3 (Crowl & Louvar, 2002)
Assuming that a car travels at an average speed of 50 km/h, how many kilometres must be driven before a fatality is expected?
Assume FAR for travelling by car=57 deaths/108

11. Answer:
Refer to table 1.4, FAR travelling by car is 57 deaths/108 hours.
Speed = 50 km/h
A death will occur every 108/57 = 1.75 x 106 hours.
Therefore, distance before a death occur = 87.5 x 106 miles

12. Fatality Rate Independent of the number of hours actually worked
Based on the general population
FAR Fatality rate

13. Question 1.5 (Crowl & Louvar, 2002)
A plant employs 1500 full-time workers in a process with a FAR of 5. How many industrial related deaths are expected per year?

14. Answer:
Expected industrial related death per year = 0.15

15. NATURE OF ACCIDENT PROCESS & SEQUENCE

16. Table 1: Common Chemical Plant Accidents (Crowl & Louvar, 2002)
Type of Accident
Probability of Occurrence
Potential for Fatalities
Potential for Economic Loss
Fire
High
Low
Intermediate
Explosion
Toxic Release

17. Causes of Losses Mechanical failure Operator error Process upsets
Natural hazards
Design Flaw
Sabotage/Arson
Unknown ???

18. Accident 3-Step Sequence
Initiation
Propagation
Termination

19. Initiation The event that starts the accident Example:
Mr. A threw away a burned cigarette bud into dried bushes

20. Propagation The event or events that maintain or expand the accident
Example:
A portion of dried bushes ignited, releasing thick smoke and hot flame. Fire starts to progress to another part of bushes

21. Termination
The event or events that stop the accident or diminish it in size.
Example:
Consumption of combustible materials in process, fire extinguisher.
More example: refer to Table 1.7, Page 19 (Crowl & Louvar, 2002)