A quantitative risk assessment framework for domino accidents caused by double pool fires

Fires spreading at limited distances one to the other can cause changes in burning rates and flame shapes due to synergistic effects. These may result in more severe consequences and in the generation of specific and more intense escalation vectors, causing a higher probability of domino scenarios. In this study, a specific approach was developed to consider synergistic effects of double pool fires in a quantitative risk assessment (QRA) framework aiming at the assessment of domino accident scenarios. The double pool fire synergy (DPFS) model developed was validated against experimental results obtained using different fuels. A comprehensive framework was developed to address the quantitative risk assessment of escalation leading to domino scenarios, combining the DPFS model, escalation probability estimation for domino accident, and Bayesian network analysis. Three case studies were carried out to analyze the impact of synergistic effects on escalation probability. The results show that synergistic effect of simultaneous multiple pool fires significantly increase the intensity of the escalation vector, and the escalation probability increases up to three orders of magnitude. Furthermore, the inclusion of synergistic effect in the analysis of posterior probability improves the accuracy of identifying the critical units in domino scenarios, contributing to a better selection of the emergency response targets.