3. How to weight?

The main drawback of most databases is that they report "average" values, which may not be representative of the site being analyzed. Indeed, depending on the level of safety (number, nature, reliability and effectiveness of safety barriers), the probability of accidents occurring will be greater or lesser. Deviating upwards or downwards from the values reported in the databases is therefore necessary if we wish to carry out a risk analysis that takes into account the specific features of the site.

In practice, there are two possible approaches to weighting a leakage frequency from a bank.

• Approach no. 1: weighting the frequency of equipment leaks by taking into account the weight of the various causes and the performance of the prevention measures implemented.

• Approach no. 2: weighting...