Define the feared event at the top of the tree
Hazard studies: fault tree (ADR detailed risk analysis method)

Generally speaking, a dread event can be defined as an undesirable event.

Within the framework of risk analysis, the analysis of hazardous phenomena that can generate human, material or environmental damage begins with the identification of feared events.

In hazard studies, different types of dreaded events are studied:

• loss of containment for flammable and/or toxic liquids and gases;

• chemical reactions;

• product decomposition.

It is imperative to define the feared event precisely, so as to guide the working group in identifying the causes that may lead to its occurrence.

For example, if the risk analysis concerns a loss of containment, the dreaded event "equipment leak" is too generic; it is therefore preferable to associate a qualifier (small, medium or large leak) or, better still, a breach size....