Technological hazard analysis: FMECA

FMECA (Failure Mode, Effects and Criticality Analysis) is an analysis that is essentially based on the following concepts:

  • Failure: a situation where an element or system is no longer capable of fulfilling a required function.
  • Failure mode: effect through which a failure is observed on an element or system.
  • Cause of failure: events leading to the failure mode.
  • Effect of a failure mode: consequences associated with the loss of an element’s ability to fulfil a required function.
  • Criticality of failure: semi-quantitative evaluation of the causes (probability) and effects (severity).

FMECA is a suitable method of highlighting the failures of various types of equipment, such as instrumentation and important equipment for the safety of an installation, for example. This method can also integrate causes of failure that are internal and/or external to the system.

A certain amount of feedback on the equipment in question is required to conduct a relevant analysis (the starting point for constructing a failure tree of a given system, and for evaluating the SILs of a system’s safety features).

Finally, compared with a HAZOP review, FMECAs enable the origins of equipment failure (e.g. control loop) that could lead to a process deviation or an accident to be investigated in greater detail.