There appears to be a disconnect between the definition of an explosive, the classification criteria for other substances, and the explosives test scheme in the UN Manual. At issue is that the UN testing scheme does not exempt substances that are not intended as explosives and that do not function as such by the extreme rapid release of gas and heat from testing even though the definition of explosive does exclude them. If you approach classification from a definitional perspective (i.e., the perspective of whether a substance functions in a similar manner to that of an explosive) you could reach one conclusion (i.e., nonexplosive) whereas if you apply the test scheme in the UN manual without considering the explosives definition you may arrive at a different classification conclusion, leading some substances to be reclassified as explosives, even though the only hazard may be that they burn. How is safety enhanced by classification as an explosive when the flammability hazard is more effectively communicated by a Division 4.1 classification? Within the international OECD-IGUS forum and the UN explosives working group, there has been some discussion of solving the problem by raising one or more test thresholds. That may help some; but will it solve the disconnect between the definition of an explosive and the test criteria in the UN Manual? It would seem that even if the test bar were raised, there will continue to be the testing of substances that do not by chemical reaction function by the extreme rapid release of gas and heat. To make the explosive definition and the test requirements consistent, the right approach may be to only subject substances not intended to function as an explosive to explosive screening testing when considered to function by extremely rapid release of gas and heat (i.e., detonate) by a chemical reaction within itself. The UN Manual text in paragraph 1.1.7 makes clear it is not a "cookbook" for classification when it states that it "is not a concise formulation of testing that will unerringly lead to proper classification. It therefore assumes technical competence on the part of the testing body." It gives competent authorities discretion "to obtain a reliable and realistic assessment of the hazard of a product."
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