Quantification of risk reduction due to the installation of different lightning protection solutions for large atmospheric storage tanks

In the past decades the impact of natural events in industrial plants have triggered a number of technological accidents. Accidents may be followed by the release of relevant quantities of hazardous substances, with relevant consequences for the population and for the environment. Technological accidents triggered by natural events are very common in the industrial facilities, although only recently their specificity was recognized and they are now indicated as Natech (natural-technological) events. In particular, lightning strikes are a recognized hazard that causes the loss of large quantities of product and compromise the safety for chemical and oil industries. Past accident analysis evidenced that the most vulnerable installations to lightning strike are oil tank terminals of oil refineries. Since there is general agreement that a total protection from lighting hazard is impossible, quantitative risk assessment is needed to assess the possibility of technological accidents caused by lightning strike. The aim of the present study was the development of a dedicated methodology for the quantitative assessment of risk due to technological accidents triggered by lightning strikes in chemical and process industries. In particular the accidental scenarios have been identified and the frequencies for every scenario have been calculated. The method developed was applied to assess the risk reduction that can be achieved by the installation of air terminals to protect storage tanks in lightning prone zones. Different solutions are compared in order to select the best protection system for different storage tanks and lay-outs. © Copyright 2014, AIDIC Servizi S.r.l.