In Failure Mode and Effects Analysis (FMEA), Risk Priority Number (RPN) is a measure of the potential risk associated with a particular failure mode. It is calculated by multiplying the likelihood of occurrence, the severity of the effect, and the detectability of the failure mode.
The likelihood of occurrence is a measure of how likely it is that the failure mode will occur, with a higher number indicating a higher likelihood of occurrence. The severity of the effect is a measure of the impact of the failure mode on the system or product, with a higher number indicating a more severe impact. The detectability of the failure mode is a measure of how easily the failure mode can be detected, with a higher number indicating that the failure mode is more easily detected.
The RPN is used to prioritize potential failure modes and determine which ones should be addressed first. Failure modes with a higher RPN are considered to be more risky and should be addressed as a priority. The RPN can also be used to track the effectiveness of corrective actions implemented to mitigate or eliminate the failure mode.