(71ar) Integrating Alarm Management into Your PHA and LOPA Processes

Operator response to alarms is a commonly used layer of protection to reduce risk and to prevent an upset from escalating into an incident. When alarms are used as independent protection layers (IPL), they must follow the applicable standards, guidelines, and regulations for both alarm management (ISA-18.2) and process safety (IEC-61511 and OSHA PSM). This paper will discuss how to integrate the work processes of alarm rationalization, process hazard analysis (PHA), and layer of protection analysis (LOPA) to effectively bring together the alarm management and process safety lifecycles.

Integration of these work processes can deliver significant benefits including enhanced traceability and seamless management of change, as well as a more effective design – ensuring that the operator’s response to alarm provides the expected level of risk reduction. Appropriate characterization of the alarm layer of protection also helps to ensure that other layers of protection (such as a Safety Instrumented System) are neither over-designed nor under-designed.

Specific topics include:

• Integration of alarm management into the overall on-going PSM work process

• Properly accounting for the consequences of deviation (mitigated vs. unmitigated)

• Analyzing operator response time in relation to process safety time and safe operating limits

• Analyzing alarm system performance to determine actual demand rate and initiating frequency

• Determining alarm proof test frequency and testing requirements

• Effective operator training

• Setting the alarm priority to indicate the criticality of the alarm in relation to others

• Use of alarm response procedures to help operators respond quickly and effectively

• How tools for PHA, LOPA and alarm rationalization can exchange information seamlessly facilitating the overall PSM work process