FMEA Q and A
A reader is having difficulty seeing the difference between a detection control and a recommended action, and sees them as interchangeable. This has repercussions for the linkage between the Design FMEA and Design Verification Plan, and is the subject of this FMEA Q and A article.
“The art and science of asking questions is the source of all knowledge.”
What is the difference between prevention controls, detection controls, and recommended actions? I can discern between prevention and detection controls pretty well, such as following a design-engineering standard (prevention control) versus conducting a prescribed test (detection control). I am having a hard time discerning a detection control versus a recommended action. To me, they seem interchangeable. I need to get a good understanding of this, because this will dictate how data is brought into the DVP&R, which leads me to a very similar topic.
Answer to Reader’s Question
That is a very good question. The primary difference between controls (both prevention-type and detection-type) and recommended actions is whether the task/method is “currently planned or in place.” If the task/method is currently planned or in place, it should be in the controls column. If it is not currently planned or in place, it should be in the recommended actions column. The reason for this has to do with the objective of controls versus the objective or recommended actions. Controls are used in the FMEA to support the risk ranking for occurrence (prevention-type controls) or detection (detection-type controls). They are also useful in developing the Design Verification Plan. Any task/method that is not currently planned or in place will not be part of the occurrence or detection risk assessment. The objective of recommended actions is to identify all actions that are needed to reduce risk to an acceptable level. The recommended actions are changes to current designs or tests or other changes that reduce risk. They are assigned a person to implement, and given other project management enablers, such as target completion date.
The Design FMEA inputs to the Verification Plan (DVP) in two ways. First, the detection-type controls in the DFMEA are usually part of the DVP. Second, when the FMEA team wishes to add or modify certain DVP procedures, they should enter recommended actions in the DFMEA that specifically add or modify the corresponding tests in the DVP. For example, if the FMEA team wishes to include test ABC in the DVP, the FMEA Recommended Action should say, “Add test ABC to DVP.”
Have you ever been in an FMEA meeting where the team did not agree on severity risk rating? Understanding and correctly applying severity risk is an important part of FMEA application. The next article discusses the subject of severity risk, including examples for design and process FMEAs, and offers a tip on what to do when the team does not agree on the severity risk rating.