Criteria for the escalation of fires and explosions

The escalation of fires and explosions in an industrial environment, also known as domino effects, may cause extremely severe accidental events. Nevertheless, conventional quantitative risk analysis (QRA) of process plants or industrial areas rarely includes these effects, or limits analysis to the use of threshold criteria for structural damage of equipment as directly linked to the possibility of escalation. Moreover, due to the great uncertainties in the technical literature, very conservative values are adopted to assess the possibility of propagation, thus leading to possible over-predictions of risk. The present study focuses on revision and improvement of the criteria for escalation assessment, based on updated models for fires and explosions and on recent advances in the prediction of damage to process equipment due to different escalation vectors, i.e. heat radiation, overpressure, fragment projection. Specific threshold values are identified for the primary scenarios usually considered in the risk assessment of industrial sites.