Quantification of alarm chatter based on run length distributions

An alarm is a notification of an abnormal event that requires operator action. In the process industries, owing to inefficiencies in configuring alarms, an abnormal event is often not annunciated using a single alarm. Chattering alarms are the most common form of nuisance alarms. Chattering is a condition where an alarm is annunciated excessively within a short span of time. Quantification of alarm chatter is important to evaluate the performance of various alarm generating algorithms. In this work, the concept of run length is applied to alarm data and an index is proposed to quantify the degree of alarm chatter based on run length distributions. Prominent features of the proposed index are demonstrated using real industrial alarm data.