Conducting a Failure Modes and Effects Analysis

FMEA is simply an analysis tool that identifies all the ways a particular component can fail and what its effects would be at the subsystem level and ultimately on the system. FMEA is vastly different from fault tree analysis. Fault tree analysis is a top-down analysis of faults in a system. FMEA is a bottom-up analysis that identifies failures (not necessarily faults) in the system. The fault tree starts with the top-level or system-level concern (top event) and then works down to the events that lead to that top event. FMEA does exactly the opposite it starts with the components in the system and analyzes failures and how they impact the subsystan in which it is housed and what are the propagated effects across the syston. 

FMEA is a very methodical tool that looks at every component in the system (or subsystem) under study and then identifies the ways the component can fail (failure modes). Each failure mode is further analyzed to determine what would be the effects of that particular failure mode on the system. Results are posted in tabular form (very similar to the hazard analysis worksheet). 

Construct functional block diagrams that indicate how the different system indenture levels are related. 

Assess each functional block (at the block level) and determine if its failure would affect the rest of the system. If it would not, then ignore the block. If its failure would affect the rest of the system, go down another indenture level and perform the following scheme. Continue down to the level of relevance. 

The real analysis starts here this is where the bottom-up approach commences. In each functional area where failures could adversely affect the system, look at the component failures. List the modes or ways that the component can fail. Be sure to mention what component parts would fail. 

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Conduct a failure mode and effects analysis (FMECA)... 

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