Qualitative and quantitative risk assesments caused by domino accidents in industry

The European directives known as "Seveso II" and "Seveso III", transposed into French law by Decrees 99-1220 of December 28, 1999, 2000-258 of March 20, 2000, 2014-284 and 285 of March 3, 2014, and Orders of May 10, 2000 and May 26, 2014, respectively, have introduced obligations linked to the consideration of the domino effect in the prevention of major accidents involving hazardous substances or preparations present in certain categories of installations classified for environmental protection (ICPE) subject to authorization. The directives therefore impose the need to examine the consequences of an accident on neighboring facilities (concept of domino effect), either through interaction between equipment or facilities within the same establishment, or through interaction between neighboring or nearby establishments. As a result, the contents of the hazard study must contain a good description and approach to possible domino effects.

This article begins with a review of some accidents involving domino effects. The definitions and characteristics of a domino effect are then presented. The notions of escalation vectors and damage threshold vectors are examined. Two practical qualitative methods based on effect distances are described. Finally, a quantitative method for estimating domino effect risks is described step by step.