Deriving major accident failure frequencies with a storybuilder analysis of reportable accidents


  • This article was originally presented at the 8th Global Congress on Process Safety, Houston, Texas, April 1–4, 2012.


Quantitative risk analysis (QRA) is used in the Netherlands and the United Kingdom for site permitting and land-use planning around industries with dangerous substances. For example, individual risk contours resulting from a QRA determine where houses and other types of constructions may exist or be built. Therefore, both industry and regulators ask for models and data that are up to date. Data used for input include the failure frequency of failure scenarios. In the past, updating frequencies required was undertaken through costly single snapshot investigations. As major hazard accidents are investigated by the Labor Inspectorate by decree, a possibility arises to use this accident investigation data for a progressive updating scheme. Recent major accidents in the United Kingdom and in the Netherlands were analyzed with the Storybuilder method. Underlying failure causes at operational and management levels were investigated and stored in a structured database. The amount of equipment present at plants was explored using various paths. This demonstrated that failure scenarios and frequencies can be updated on a regular basis by combining the accident data with the equipment data. © 2012 American Institute of Chemical Engineers Process Saf Prog, 2012