Step 1 FMEA Number : This should be a log controlled number for tracking the document.

Step 2 Part number/process step : FMEA can be done for a particular part or a process. While doing it for a process, we need to do for each step in that process. This needs to be captured in the 1st column of FMEA sheet.

Step 3 Potential Failure Mode : Now the critical steps will start and first we need to understand what is potential failure mode for a process step or a part:

How can the process / task fail to meet specification ?

What would a customer consider as failure/rejection? (End User, Subsequent operation, Service)

Manner in which process could potentially fail to meet the process requirements and / or client’s intent

Step 4 Potential causes of failure : Describe in terms of something that can be corrected or controlled. Be specific. Try identify the causes that directly impact the failure mode, i.e., root causes.

Step 5 Potential Effects of failure : Describe effects of failure in terms of what customer(s) might notice or experience, customer here could be the subsequent operations. We can understand this with an example – suppose there is a failure mode in terms of leak from a clamp, the effect could be wet floor.

Step 6 Current control : In this step capture current controls to prevent or detect the failure mode, based on this we have to assign the Detection rating.





Severity (S): Severity rating is the effect of the failure on the rest of the system if the failure occurs. These values are often indexed from 1 to 10 (Low to high severity). A value of 1 means the user will be unlikely to notice and with a 10 meaning that the safety of the user is in jeopardy.

**Important Note : Once we bring in more controls the occurrence will reduce and Detection rating will also improve but Severity rating will remain the same.

Occurrence (O) : Values for this index generally index from 1 to 10 with 1 being virtually no chance and 10 being near certainty of occurrence. Only occurrence resulting in failure mode to be considered and If available please use statistical data to determine occurrence ranking.

Detection (D): D is the measure of the effectiveness of the current controls in place to identify the potential weakness or failure prior to release to production. This index may also range from 1 to 10. A value of 1 means this will certainly be caught whereas a value of 10 indicates the design weakness would certainly make it to the production without detection.

Calculation of RPN

Risk Priority Number (RPN): Once you have given ratings to “S”, “O” and “D” then it is very easy to calculate RPN for that particular row item(part/process step).

RPN = S*O*D

Now identify Failure modes with highest RPN values, next step would be to review and update the current control plan so that risks go down. This will help you to reduce Occurrence and improve Detection.

Things to remember: