Performance of control room operators in alarm management

Abstract

Pipelines transport millions of barrels of petroleum products every day. These systems have significant safety concerns. The BP oil spill in the Gulf of Mexico, while concerned with oil and gas extraction rather than distribution, shares many of the same safety and reliability issues as distribution systems, and demonstrates the significant potential for major disasters in the pipeline industry. In this work, a research study is being conducted to further understanding of the role of operators in the management of alarm systems and to measure the performance of operators in handling abnormal situations like pressure loss, liquid inflow/outflow variation and alarm floods. In an Abnormal Situation Management (ASM) consortium traditional interface study, improving the human machine interaction (HMI) in designing the operator’s user interface resulted in 41% less time for the operators to deal with events like leaks, power failures, equipment malfunction and equipment failures in an unstable plant (Errington, 2005). To evaluate the impact of different alarm rates and interfaces on operator performance, a liquid pipeline simulation experiment of 1 hour was developed and the operators ran the experiment repeatedly at different alarm levels: chronological and categorical displays with the alarm rate of 15 alarms per 10 minutes (chronological display only), 20, 25 and 30 alarms per 10 minutes (the last rate with the categorical display only). Twenty five pipeline and refinery operators participated in this research, and the performance of operators was measured in terms of acknowledgement time, response time and the accuracy of response. Results showed that the operator’s performance in terms of response time was significantly different between 25 and 30 alarm rates. Experiments to compare the response times in both the alarm windows did not show significant difference statistically, but the means were better in categorical display. This study will be useful in developing new standards on operator performance.