BS EN 60812:2006 describes failure mode and effects analysis (FMEA) and failure mode, effects and criticality analysis (FMECA), and gives guidance as to how these techniques may be applied to achieve various reliability programme objectives, by:
- outlining the basic principles
- identifying appropriate terms, assumptions, failure modes, and criticality measures
- providing the procedural steps necessary to perform an analysis
- providing examples of the typical forms used.
Failure is the loss of the ability of an item to provide its required function. By identifying the potential for system elements to fail, the designer may be able to eliminate the causes, or mitigate the failure effects to avoid undesirable consequences on the system. Failure mode and effect analysis (FMEA) is a logical process aimed at identifying the potential failure modes of the elements of a system; the respective causes of failures; and the failure effects, initially on that element and then on its particular part of the larger system. A failure effect at a lower level may then be a failure cause for an item in the next higher level, hence the end effect on the system as a whole may be identified.
Failure modes, effects and criticality analysis (FMECA) is an extension of FMEA, by including estimates of the likelihood and the severity of each failure mode. When these factors are combined, it provides a measure of its criticality, allowing for identification and prioritisation of countermeasures.
These analysis techniques are very versatile, being applicable to all types of processes and services, as well constructed or manufactured systems. They are most cost effective when performed early in the development cycle, being up-dated as the design develops.