Empirically evaluating and developing alarm rate standards for liquid pipeline control room operators

The liquid and gas pipeline community has recently been faced with the challenge of new governmental regulations set forth by congress which are being implemented by PHMSA (an arm of the DOT). These new governmental regulations need to understand the role of the human in the loop as part of alarm management systems. To investigate alarm rate standards a repeated measures design was developed that included a series of ten (10) simulated liquid pipeline operator scenarios utilizing high fidelity liquid pipeline simulation software (Stoner Pipeline Simulator). A total of 39 participants volunteered for this study. Participants completed two subsets of experiments, five were completed using an alarm display presenting alarms by time (chronological) and the remaining five experiments were completed using a categorical alarm display. Statistically significant differences were found to exist in participant response time, acknowledgement time, and accuracy of response given different alarm display types and alarm rates. Use of the categorical alarm display resulted in significantly reduced alarm acknowledgement and response times. Also, a severe operator performance reduction with regard to alarm handling was observed when the alarm rate was increased from ten alarms per ten minutes (10-alarms/10-minutes) to twenty alarms per ten minutes (20-alarms/10-minutes)

Performance of control room operators in alarm management

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

Effect of different alarm interfaces on controller response

Pipelines transport millions of barrels of petroleum products every day. Oil and gas pipelines have become important assets of the economic development of almost any country. Government regulations or internal policies regulate the safety of the assets for the population and environment where these pipelines run. Various strategies and technologies have been introduced for monitoring pipelines, but the most common technology to protect pipelines from occasional hazardous incidents is Computational Pipeline Monitoring (CPM). This technique collects and gathers information from the field related to pressures, flows, and temperatures to estimate the hydraulic behavior of the product being transported. Using the gathered information CPM systems compare its values with standard values and provides a notification if any anomaly or unexpected situation occurs. The result is an alarm to an operator in a supervisory control room. According to Hollifield, it is becoming an increasing problem that there is no standard for plant operators yet, whereas improved design can lead to better performance (Hollifield et. al., 2007). So, the objective of this experiment was to explore the effect of different alarm interfaces on controller response at different alarm rates. A simulated liquid pipeline system was developed and a between subject experimental design was performed to evaluate three different types of alarm window interfaces (Categorical, Chronological, and Revised Categorical), two alarm rates (10 in 10 minutes and 20 in 10 minutes), and three levels of alarms (high, medium, and low). Thirty one participants participated in this research, and the performance of participants was measured in terms of acknowledgement time, response time and the accuracy of response. Results showed that the participants’ performance in terms of response time, acknowledgement time, and accuracy of response was significantly different between chronological, categorical, and revised categorical displays. Data analysis showed that the means were shorter in revised categorical display in terms of response time, acknowledgement time, and accuracy of response. This study will be useful in developing new standards for alarm display