Glossary · Risk estimation methods
Failure Modes and Effects Analysis (FMEA)
Also known as: FMEA, FMECA
German: Fehlermöglichkeits- und Einflussanalyse (FMEA)
In reliability and safety engineering, Failure Modes and Effects Analysis (FMEA) is a systematic, inductive method for identifying the failure modes of items, their effects, causes and existing controls, and for prioritizing actions. When criticality is assessed as well, it is called FMECA.
- Machine safety
- Risk assessment
In one sentence
Failure Modes and Effects Analysis (FMEA) works bottom-up from component failures to their effects, to find weak points and prioritize improvements.
Example
An FMEA of a press safety circuit examines what happens if a contactor welds, a position switch sticks or a cable breaks, and whether diagnostics detect each failure.
How it applies
- Risk analysis: FMEA is inductive: it starts with each item and asks how it can fail and what follows. It complements top-down methods such as fault tree analysis.
- Functional safety: FMEA is a common way to support diagnostic coverage estimates and to find faults in safety-related parts of control systems. It covers single failures well; combined failures and common-cause failures need extra attention.
- Prioritization: IEC 60812 describes several ways to rank failure modes, including the risk priority number and criticality matrices. Document the chosen scheme and its limits.
- Technical documentation: Keep FMEA worksheets under change control and link them to design items, hazards and verification tests. An FMEA that is not updated after design changes quickly misleads.
FMEA vs. FTA
FMEA works bottom-up from failure modes to effects. FTA works top-down from an undesired event to its causes. Using both gives better coverage than either alone.