5. Our advice

5.1 Develop other examples

The simple example of the "Flammable Liquids" class has been presented, and the link between physico-chemical criteria and the choice of hazard category is well understood.

As other simple examples to develop, we recommend the following classes:

• "Flammable gases": the criteria are the lower and upper explosion limits (LEL, UEL, respectively), which are easy-to-understand concepts;

• "Flammable solids": the criteria are the speed and duration of combustion, and whether or not wetting the substance stops the spread of flames; these tests are easy to represent and relate to the substance's "dangerousness";

• "Acute toxicity",...