Definition and Analysis of a New Risk Priority Number Concept

  • Jens Braband


Risk Priority Numbers (RPNs) are a powerful qualitative method for discovering and prioritising critical issues in early design phases. They have become very popular in particular as a tool in automotive or software Failure Modes, Effects, and Criticality Analysis (FMECA). However, it has been shown that the existing RPN concept is seriously flawed. This paper presents a theoretical approach towards a new RPN concept, called the Improved Risk Priority Number (IRPN), which is based on a sound model of risk and can be used with equal ease, but does not suffer from the shortcomings of the existing RPN concept. A particular example from a railway application is discussed.


Failure Mode Risk Priority Number Judgement Error Early Design Phase Potential Failure Mode 
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  1. 1.
    Bowles, J.: Failure Modes, Effects, And Criticality Analysis: What It Is And How To Use It, Tutorial, RAMS 1999Google Scholar
  2. 2.
    “Potential Failure Mode and Effects Analysis In Design (Design FMEA) and Potential Failure Mode and Effects Analysis In Manufacturing and Assembly Processes (Process FMEA) Reference Manual”, Society of Automotive Engineers, Surface Vehicle Recommended Practice, J1739, July 1994.Google Scholar
  3. 3.
    Analysis techniques for system reliability — Procedure for failure mode and effects analysis (FMEA), IEC 60812Google Scholar
  4. 4.
    Bowles, J.: An Assessment of RPN Prioritization in a Failure Modes Effects and Criticality Analysis, Proc. RAMS2003, Tampa, January 2003Google Scholar

Copyright information

© Springer-Verlag London 2004

Authors and Affiliations

  • Jens Braband
    • 1
  1. 1.Siemens AG -Transportation SystemsBraunschweigGermany

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