1. Reminder of the Quantified Risk Analysis (QRA) method

1.1 Deterministic versus probabilistic approach

In the field of industrial safety, a risk can have two components:

• its probability of occurrence ;

• the severity of the damage (which can be assessed in terms of personal safety, property safety, environmental damage or damage to the company's reputation).

Generally speaking, in the oil, petrochemical and chemical industries, risk tolerability/acceptability criteria take these two components into account. A typical example is given in the table 1 .