1. Example definition. Modeling

We will take as an example a propane unloading installation supplying workshops, shown in figure 1 .

There are many ways of segmenting the context, but it should be noted that for a given division defining the system to be analyzed, the rest of the context is found in the system's environment. So, whatever the situation of the boundary chosen between the system and its environment, the sum of the two always gives the whole context.

The most dangerous system in this context is the propane depot. It will therefore be the focus of the analysis (figure 2 ).