3. How do you classify dangerous goods whose characteristics are not well known?

When the characteristics of the material are not sufficiently known to determine its classification with certainty, additional laboratory tests must be carried out, in accordance with ADR § 2.2. To limit the number of tests to be carried out, the Manual of Tests and Criteria includes "pre-selection" tests for certain classes, to determine whether or not a material should be subjected to all the tests in the class.

The weight-of-class system described in § 2.1.3.5.3 and § 2.1.3.10 above can also be used to classify a mixture whose physico-chemical characteristics are unknown, but for which the classification of each component is known. In this case, only the classification of each of the materials in the mixture is taken into account, not their relative quantities.

In case of doubt, the most unfavorable classification, corresponding to the...