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Human Error Analysis in a Permit to Work System: A Case Study in a Chemical Plant
Mehdi Jahangiri1, Naser Hoboubi2, Akbar Rostamabadi2
1Research Center for Health Sciences, Department of Occupational Health Engineering, School of Health, Shiraz University of Medical Sciences, Shiraz, Iran.
Safety and Health at Work
|March 26, 2016
Summary
Human error in permit to work (PTW) processes can cause accidents. This study estimated the human error probability in a chemical plant
Area of Science:
- Occupational Safety and Health
- Risk Management
- Chemical Engineering
Background:
- Permit to Work (PTW) systems are formal procedures to control hazardous work.
- Human error within PTW processes poses a significant risk for industrial accidents.
Purpose of the Study:
- To estimate the probability of human errors in Permit to Work (PTW) processes within a chemical plant.
- To identify specific tasks with high human error probabilities in PTW systems.
Main Methods:
- A cross-sectional, descriptive study utilizing Hierarchical Task Analysis (HTA) to dissect the PTW process.
- Application of the Standardized Plant Analysis Risk-Human (SPAR-H) reliability method for human error probability estimation.
Main Results:
- The mean probability of human error in the PTW system was calculated to be 0.11.
- Flammable gas testing emerged as the task with the highest human error probability, at 50.7%.
Conclusions:
- The SPAR-H method effectively quantifies human errors in PTW systems, aiding in the development of targeted risk reduction strategies.
- Recommendations include modifying performance shaping factors and task dependencies to minimize error likelihood.
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