Structure of Human Errors in Tasks of Operators Working in the Control Room of an Oil Refinery Unit

In the present research, human errors existed in tasks of operators working in two control rooms (Northern and Southern control rooms) in the Tehran oil refinery are identified and evaluated. Then, corrective strategies and actions are advised to decrease errors. At first, using hierarchical task analysis (HTA) method, four positions including shift controller, head operators, control room's operators, and outside operators are analyzed. Afterwards, human errors in the considered positions are identified and assessed using technique for retrospective and predictive analysis of cognitive errors (TRACEr). Results present 670 internal errors and 738 external errors in the Northern sector while 661 internal errors and 744 external errors in the Southern sector. In two sectors, this number of errors was identified for 27 major tasks and 108 minor tasks. Action errors are the most repeated errors among the internal errors while violation errors are the least. In addition, most of external errors are related to communication errors while the least errors are related to time and sequence errors. According to results of applying psychological error mechanism (PEM) in the considered positions, people's distraction is the main factor causing errors. Performance shaping factors (PFS) identifies lack of training as the major factor for errors. Using TRACEr, all external and internal errors, psychological error mechanism, and primary factors of errors in the control room can be detected.