4. Quantified LOPA method

4.1 Principle

The quantified LOPA approach corresponds to a variation of the LOPA method in which :

1. frequencies of initiating events tend to be more representative of the configuration studied (use of sector-specific databases and/or analysis of feedback);

2. the failure probabilities of the safety barriers are estimated using a "computational" approach (where possible, depending on the type of barrier), taking into account :

• for instrumented barriers: equipment failure rates, architectures, test periods, etc,

• for human barriers: the main parameters influencing the probability of error or failure (level of training, level of stress, complexity of the action, etc.);...