Risk Matrix and Event Tree Based Half Quantitative Alarm Priority Analysis for Alarm Systems

Abstract

For chemical process normal operation, alarm systems play a critical role in industry to meet the demands of safety, quality and efficiency. However, a serious problem exists in industry: too many alarms raising shortly need to be handled by the operator. In this situation, appropriate alarm priority is extremely important, that is, the more important alarms at any given time are obvious to the operator, and this helps the operator to decide which alarms to deal with when several occur at the same time. Typically, the method to prioritize alarms is based on the severity of the consequences and the time available for the alarm, which depend on the operator’s experiences highly. Herein, a half quantitative alarm priority analysis is proposed to make alarm priorities more reliable and effective. Event tree analysis (ETA) is used to assess the risk consequence when an alarm occurs. ETA is one of quantified risk assessment techniques and is used for identifying and evaluating the sequence of events in a potential accident scenario following the occurrence of an initialing event. Finally, a case study is given to prioritize alarms using the algorithm that we introduce above, and illustrates the advantages of this algorithm through an example of an industrial application.