4. Characteristics of domino effects

The main elements to characterize a domino effect are :

• a primary or initial event in a primary accident scenario that initiates and triggers the domino effect accident sequence;

• the propagation effect following the initial main event, due to the effect of escalation vectors caused by the primary event;

• one or more secondary accident scenarios, affecting the same unit or other target units of an industrial facility;

• intensification or worsening of the consequences of a primary event, due to the effects of secondary scenarios.

The MADS hazard model can be used to schematically illustrate the process and characteristics of domino effects, as shown in the simplified example in figure