A methodology for alarm classification and prioritisation

Concerns the prioritisation of process alarms. The classification of instrumented protective functions using the IEC 61508 risk graph method assesses the consequences that would arise from a trip failing to operate on demand, where risk is a combination of probability of occurrence and the degree of hazard arising from the consequences. A similar process has been developed for setting alarm priorities, with adaptations to match it to the circumstances that usually surround alarms rather than trips. The classification of alarms is biased more towards consequences because the regularity of the alarm occurrence has no bearing on its priority