Risk priority number

With the calculation of the risk priority number (RPN), an attempt is made to create an order of risks.

The RPN is determined by multiplying the evaluation numbers S, O and D (RPN = S · O · D, so values between 1 and 1000 can be assumed. The prerequisite for existence is at least RPN. It is an RPN in comparison to other RPNs. In the same FMEA, a declaration of the best/worst direction is permitted, but is not generally observed according to DIN EN 60812. The purpose of the RPN is a countermeasure. It is a case of always assessing and questioning the severity of failures in the prioritization. DRBFM, the AMDEC system used by Toyota, completely ignores the definition of important metrics. Actions are only taken based on common sense or following group discussions. The risk priority number is increasingly being replaced by other evaluation methods, e.g. risk matrix.

Glossary Technical terms at a glance