The present study aimed at the development of a quantitative approach for the assessment of safety barrier performance in the prevention of fire escalation leading to domino accidents. In order to obtain a synthetic evaluation of the protection barriers performance, specific key performance indicators (KPIs) were defined, incorporating the results of probabilistic assessment of barrier performance. The results confirmed the important role of safety barriers performance in controlling the expected frequency of domino scenarios. The KPI analysis allowed determining the performance of different barrier types accounting for specific site factors. The results allowed a more detailed assessment of the expected frequency of secondary mitigated and unmitigated scenarios in the assessment of risk due to domino effect. (C) 2016 Elsevier Ltd. All rights reserved.