Modelling Failure Modes and Effects Analysis

Presents a critical review of the method of FMEA and in particular of the risk priority number (RPN) used for ranking failure modes. Though the method itself is of great use, the calculation of the RPN lacks a proper model as a base and is thus internally inconsistent and potentially misleading. Proposes an alternative procedure, based on a simple model and using expected costs as the basis for ranking failure modes.