Risk Based Safety Assurance: towards a defensible and practical methodology

Edwards, C.B.H. and Westcott, M.

The estimation of safety assurance for complex systems using risk based methodologies requires ranking of accident risk and (implicitly) the estimation of acceptable residual risk following system deployment. The paper describes a methodology for estimating and comparing risks, based on combining the derived Probability Density Function (PDF) of accident probability (Likelihood) with actual accident result (Outcome). The paper also suggests a method for calculating the residual risk after the completion of hazard mitigation activities, together with a possible methodology for implementing this approach. The effect of uncertainty on risk estimates, the importance of risk interpretation and the difference between risk and safety targets are also discussed.

Cite as: Edwards, C.B.H. and Westcott, M. (2012). Risk Based Safety Assurance: towards a defensible and practical methodology. In Proc. Australian System Safety Conference 2012 (ASSC 2012) Brisbane, Australia. CRPIT, 145. Cant, T. Eds., ACS. 55-68

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