User Guide to Thresholds and Classification - Environmental ...

26User Guide for Thresholds and ClassificationsNote that substances that are accepted for classification into subclasses 1.1–1.6 are those that passthe threshold tests as given in the technical specifications above for defining the threshold forsubstances with an explosive property, but not including substances that show insufficient thermalstability by giving a positive result in test type 3(c), Test Series 3, in section 13.6, pp 117–119, of theUN Manual of Tests and Criteria, and articles, packaged articles, or packaged substances that showinsufficient thermal stability and/or impact resistance by giving a positive result in any of the testsdescribed in Test Series 4, section 14, pp 123–130, of the UN Manual of Tests and Criteria (these areitems considered too dangerous to transport).2.4.2. Categories for explosive substances and articlesExplosive substances are also divided into the categories (UN compatibility groups) A–H, J, K, L, N, and Sdescribed below. A substance or an article is classified as being in a particular category if it meets the criteriafor that category. The criteria for the categories for types of explosives and their properties are based on thepremise that substances within groups are unlikely to result in unintended detonation or deflagration when inproximity to each other, and are given in the Table 1 in Part 2 of Schedule 1 of the classification regulationsas follows.Category APrimary explosive substances that are very sensitive to heat, impact, or friction, or are able to transmitdetonation or deflagration to secondary explosive substances close to them, as measured by the impact,friction, and small-scale burn tests in test types 3(a), (b), and (d), Test Series 3, section 13, pp 67–122, ofthe UN Manual of Tests and Criteria. (The test criteria for these test types are in paras 13.4.1.4, 13.4.2.4,13.4.3.4, 13.4.4.4, 13.4.5.4, 13.4.6.4, 13.5.1.4, 13.5.2.4, 13.5.3.4, and 13.7.1.3 of the UN Manual of Testsand Criteria.)Category BArticles containing a primary explosive substance but not containing two or more effective protectivefeatures, or articles designed to be primers, detonators, or detonator assemblies for blasting.Category CPropellant explosive substances (deflagrating explosive used for propulsion) or other deflagrating explosivesubstances, and articles containing such explosive substances.Category DSecondary detonating explosive substances that are less sensitive than primary explosive substances andmore sensitive than substances falling into category N, or black powder, or articles containing suchsecondary detonating explosive substances; in each case without means of initiation and without a propellingcharge; or articles containing a primary explosive substance and two or more effective protective features.January 2012 EPA0109