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RPN Value in FMEA


In FMEA the Risk Priority Number(RPN) is calculated by using folowing formula

RPN = Severity of the Effect X Probability of Occurence of the cause X Probability of the Detection

490 = 7 X 7 X 10

Now the problem is Probability of detection value is taking default as 10 even thought the valuation proposal is 8.where as Effect(7) and cause(7)values are taking from valuation which are correct .

Please anyone can guide me how to prevent default value considaration of detection.




Vineeth -

You can see the calculated RPN value of individual items of a Failure Mode (defect), at cause level, detection level and at the failure mode level. At the head level of the FMEA - in the result tab, the system will display the highest RPN value of all Failure modes. For example, in your FMEA you have 3 defects with RPN values 120, 280 and 400, at the header level 400 will be displayed once you click on valuate in the results tab, against this value system will do rating of FMEA based on your rating profile assigned and overall assessment. The same logic applicable to defect also. The defect can have multiple causes and detection action, but will have only one effect. As RPN is cause * detection * effect, it's calculated at individual casue level and the highest value is displayed at defect level.

The detection value you have entered in the detection will be visible at the casue basic data in detection and also at the defect level under relevant cause tab. What do you mean by basic screen - are you refering to cause or defect basic screen?

Your next question - the preventive action is tied to the casue, cause is tied to the defect. As I said before, one defect can have multiple causes.The preventive action valuation is not considered for RPN but it will give you the prev.valuation based on the previuos cause valuation and you can set your target valuation. Preventive action is simiar to the mistake proofing activities in place in the standard manufacturing companies.

RPL will be calculated if you check the box valuation entered in the basic data of the cause and effect.And also couple of OSS notes are there, please apply them and see.If you give your valuation correctly and check valuation enetered, I dont think you will face issues in cal. RPN. Let me know if you need any additional help on this.



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