A FMEA consists of breaking a system down into what can fail, how it can fail, and why it fails, and then determining the effects of those failures on your system. FMEAs can also include the analysis of criticality, and in this case, they are referred to as FMECAs (failure mode, effects, and criticality analysis).

FMEAs are typically performed based on published standards or guidelines. However, some organizations develop their own FMEA guidelines. The most common FMEA standards include MIL-STD-1629, various automotive standards, and SAE ARP5580.

The FMEA process is a bottom-up approach to system analysis. The analyst begins at the lowest level desired for analysis, such as a part or a step in a process, and ascertains the possible failure modes associated with this item. The next step is to establish, based on system knowledge, what the resulting effects of failure modes are. Along with each end effect, the analyst might determine the severity of this effect, its probability of occurrence, and how it could be detected.

This process continues up the system tree until overall system end effects are evaluated. Once this detailed analysis is complete, some type of ranking criteria is employed. The ranking is then used to determine how critical failures can be eliminated or the risks mitigated. The main objective of a FMEA is to evaluate all parts of your system or process to ensure that system reliability and safety objectives are met.

If you are unfamiliar with FMEAs and FMECAs and would like to learn more, the following selections are excellent references: