Probabilistic Evaluation of Conservatisms Used in Section III, Appendix G, of the ASME Code

In this paper the results of a probabilistic analysis for a pressure vessel are described in which the effects of various conservatisms used in Section III, Appendix G, of the ASME Boiler and Pressure Vessel Code are assessed. The methodology used is based on the introduction of probabilistic concepts into the deterministic calculations of Section III, Appendix G, so that the appropriate variability is reflected. By comparing the estimated probabilities of failure based on the various conservatisims, the approximate margin of safety in the design of a pressure vessel has been evaluated. From this analysis, it is concluded that this safety margin is considerable. Depending upon the conditions considered to be realistic in practice, the margin could be upwards of 10 or more orders of magnitude.