“Closing the Holes in the Swiss Cheese Model”
Layers of protection for abnormal event management can be modeled as slices of swiss cheese according to James Reason. An operator’s response to an alarm is one of the first layers of protection to prevent a hazard from escalating to an incident. This presentation discusses a two-part approach to maximizing the operator’s reliability when responding to abnormal situations (“closing the holes in the swiss cheese layer”).
The first part focuses on following the best practices in the alarm management standards ANSI/ISA-18.2-2016 and IEC 62682. Examples include alarm rationalization to ensure all alarms are meaningful and to capture “tribal knowledge”, prioritization to help operators determine which alarms are most critical, alarm classification, monitoring of alarm system performance metrics, and creation of alarm response procedures. The second part addresses the impact of human factors on operator performance; including how nuisance alarms and alarm floods can lead to errant mental models, attention tunneling, misplaced salience and overall loss of situation awareness. We will also discuss how often “operator error” is really the underlying cause of alarm management incidents.