A methodology for the analysis of domino and cascading events in Oil & Gas facilities operating in harsh environments

The present study is aimed at defining a structured approach to the quantitative assessment of cascading events triggered by fire, accounting for the influence of harsh environmental conditions on the emergency response and on the performance of hardware safety barriers. A specific metric was defined in order to consider the external factors related to harsh environments on the determination of hardware and emergency safety barriers availability, with a specific focus on operations in extremely cold climates. The metric allows evaluating the time scale of emergency and the related efficiency of barriers in contrasting accident escalation. The values obtained for availability and effectiveness of barriers were input to a specific event tree analysis in order to support the quantitative assessment of accident frequency associated to cascading events. The approach is tested by its application to a case study, aimed at the assessment of the influence of extremely cold environmental conditions on the risk due to cascading events in an industrial site