Numerical Simulation of Seismic Risk and Loss Propagation Effects in Process Plants: An Oil Refinery Case Study

Process plants are vulnerable to natural hazards and, in particular, to earthquakes. Nevertheless, the quantitative assessment of seismic risk of process plants is a complex task because available methodologies developed in the field of civil and nuclear engineering are not readily applicable to process plants, while technical standards and regulations do not establish any procedure for the overall seismic risk assessment of industrial process plants located in earthquake-prone areas. This paper details the results of a case study performing a seismic risk assessment of an Italian refinery having a 85,000 barrels per day production capacity, and a storage capacity of over 1,500,000 m³. The analysis has been carried out resorting to a novel quantitative methodology developed in the framework of a European Union research program (INDUSE 2 SAFETY). The method is able to systematically generate potential starting scenarios, deriving from simultaneous interactions of the earthquake with each separate equipment, and to account for propagation of effects between distinct equipment (i.e. Domino effects) keeping track of multiple simultaneous and possibly interacting chains of accidents. In the paper the methodology, already described elsewhere, is briefly resumed, and numerical results are presented showing relevant accident chains and expected economic loss, demonstrating the capabilities of the developed tool.