User Guide to Thresholds and Classification - Environmental ...

94User Guide for Thresholds and ClassificationsTechnical description of the classification criteria for subclass 5.2 organic peroxidesA substance that meets the qualifying threshold criteria for a capacity to oxidise and is an organic peroxide isassigned a general classification of subclass 5.2.The classification of an organic peroxide is based on its capacity to cause or contribute to combustion by therelease of chemical energy or compounds that may cause or contribute to fire, explosion, or chemicaldecomposition. The classification also specifies the degree to which these effects occur by assigning acategory from A to G, as determined and evaluated by the methods described in Part II of the UN Manual ofTests and Criteria. The sequence of hazard, category A to G, is from high hazard to low hazard.Where a substance or mixture is not listed in the UN Model Regulations, the organic peroxide is assigned aclassification category using the following procedure (and set out in Figure 7.1).Preliminary tests to ascertain the potential for fire, explosive effects, or decomposition to occur are basedon the:effects of ignition sources, using any test method that will identify those materials that will reactviolently under little or no confinement;sensitivity of the substance to impact and to friction, using the tests described in Test Series 3 forexplosive potential in the UN Manual of Tests and Criteria (pp 67–122); andthermal stability and sensitivity to exothermic decomposition of the substance, using an appropriatecalorimetric test method such as differential scanning calorimetry or adiabatic calorimetry.Based on the results of the preliminary tests, the organic peroxide‘s capacity to oxidise can bedetermined by its response to one or more of the following tests.The self-accelerating decomposition temperature (SADT), determined as described in Test Series H.The degree of heating under confinement, determined as described in Test Series E. If the test resultis a ‗violent reaction‘, the degree of thermal explosive power of the substance is determined asdescribed in Test Series G.The degree of mass hazard explosive power, determined as prescribed in Test Series F. Test SeriesF may also be used as a preliminary test to determine sensitivity to propagate detonations.The degree of propagation of deflagration determined as prescribed in Test Series C. If the testresult is ‗positive‘, the degree of deflagration when confined is determined as prescribed in TestSeries D.The degree of propagation of detonation determined as prescribed in Test Series A. If the test resultis a ‗positive‘, the degree of detonation when confined is determined as prescribed in Test Series B.However, Test Series A is not required if the result of Test Series E is ‗no‘ and the Test Series Fresult is ‗low‘ or ‗no‘.Tests Series B, D, or G is used to establish the degree to which the effects of the organic peroxide may berelated to mass or confinement in a container or package.Test Series A–H refer to the tests for organic peroxides and self-reactive substances in sections 21–28,respectively, of the UN Manual of Tests and Criteria.January 2012 EPA0109