Abstract
The increasing degree of automation and complexity of process plants raises the requirements on operators in monitoring and controlling process flow. Unfortunately the fast developments of automations are often not accompanied by understanding and consideration of the operators’ capabilities. Therefore the number of accidents particularly caused by wrong decisions of operators is increasing. A concrete example is given by the explosion at Texaco Milford Haven refinery. Key factors that emerged from the Health and Safety Executive‘s (HSE‘s) investigation are that the control room displays did not help the operators to understand what was happening and there were too many alarms and they were poorly prioritized (HSE, 1997). Common problems that had caused disasters are equipment failures or software faults, insufficient knowledge of the operator about the process and system design failure due to the ignorance or misunderstanding reaction to the displayed information (Kletz et al., 1995). While the safety analysis methods focus on the errors caused by the components, there are currently no methods that are focusing on finding possible causes of errors in the system that lead to operator‘s failure.
In previous researches by the author, a specific analysis method was developed. By means of the method, the relationship between alarms, their causes and consequences can be recognized, so that control systems and control rooms can be designed accordingly to better understand operators’ requirements in performing remedial actions (Löwe et al., 2010). This new developed method includes a technique to identify the Performance Influencing Factors (PIFs). The PIFs evaluation allows us to quantify how significant a specific factor affects the operator’s performance during their work. This paper shows the determination of PIFs global weight (for the process industry) on several facilities of a refinery in Germany. The quantification of PIFs enables the identification of sources of errors and the implementation of accurate improvements in the system.
