User Guide to Thresholds and Classification - Environmental ...

35User Guide for Thresholds and ClassificationsTermUN Model RegulationsUN PG I, II, and IIIDefinitionEleventh revised edition of the Recommendations on the Transport of DangerousGoods Model Regulations (United Nations, 1999b).United Nations Packing Groups I, II, and III. Following the UN Model Regulations,they relate to packaging with a high level of ability to contain the contents through topackaging with a lesser ability to contain the contents. They are used to refer to someclassification categories as having a high degree of hazard through to a lesser degreeof hazard respectively.3.3. Threshold tests for substances with flammable propertiesTests for flammability include finding the temperature at which a substance ignites, and testing the rate atwhich a substance burns. For example, the threshold test for flammable liquids is the determination of itsflashpoint.The approach taken to defining tests and criteria for thresholds for flammable substances is as follows.a. In some cases, because of the sensitivity and degree of hazard of the substance and for the sake ofconsistency in results, the criteria depend on precise testing procedures being followed. In these cases,the Hazardous Substances (Classification) Regulations 2001 specify the specific testing procedures inone of two ways:i. A narrative description of the test method (this allows equivalent tests to be performed); orii. The reference to a particular test is specified in the regulations, in which case only that test will beaccepted.b. When the criteria have a well-defined and universally understood meaning (for example, the closed cupflashpoint test), the regulations are limited to specifying the criteria, enabling any appropriate test to beused. This approach also permits calculation or estimation methods to be considered (for example, formixtures).This document gives some guidance about the test protocols or methods recognised as acceptable tests forthe specified threshold criteria. In general, the test protocols or methods that are acceptable are specified inthe:UN Model Regulations (United Nations, 1999b (11th revised edition)); orUN Manual of Tests and Criteria (United Nations, 1999a (3rd revised edition)).3.4. Technical description of the elements of the flammable propertythresholds and classification systemIf a substance meets any one of the threshold criteria described in the following sections, it is considered aflammable substance within the meaning of the HSNO Act. These criteria are contained in Schedule 2 to theHazardous Substances (Minimum Degrees of Hazard) Regulations 2001.January 2012 EPA0109