Equipment vulnerability assessment (EVA) and pre-control of domino effects using a five-level hierarchical framework (FLHF)

The primary event, damage vector, escalation scenario and escalation network are the fundamental components of any domino effect, and in literature, quantitative risk assessment (QRA) is the main topic of investigation for such escalating accidents. However, a QRA's implementation and application are complicated, and its results are currently not very useful in industrial practice for implementing prevention, protection and control measures. In this paper, the use of an equipment vulnerability assessment (EVA) focusing on the probability of escalation scenario occurrence is suggested, which could provide a deep understanding at the elemental level, while QRA is used at the system level. Specifically, the outline, methods and programme for EVA are discussed. In addition, a five-level hierarchical framework (FLHF) is proposed to prevent and control domino effects comprehensively and systematically, which includes Level 1-Prevention of loss of containment (LOC); Level 2-Safety distance, safety inventory and layout optimization; Level 3-EVA and safety design, safety improvement; Level 4-Reengineering of layer-of-protection analysis (LOPA); and Level 5-QRA of the domino effect. The quantification and implementation of each level are also discussed in detail.