ERT 312 LECTURE 2 Accident & Loss Statistics

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

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

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

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

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

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

Equation 3

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

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

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

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?

Answer: Expected industrial related death per year = 0.15

NATURE OF ACCIDENT PROCESS & SEQUENCE

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

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

Accident 3-Step Sequence Initiation Propagation Termination

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

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

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)