User Guide to Thresholds and Classification - Environmental ...

46User Guide for Thresholds and ClassificationsMeasuring the flammability of liquidsThe classification criteria require the flashpoint to be determined using a closed cup method. There are anumber of internationally recognised closed cup test methods, of which several are specified in section 2.3.3of the UN Model Regulations.These test methods are acceptable means of determining the classification criteria, because the regulationsmade under the HSNO Act do not specify a particular means. However, the EPA generally expectsflashpoints to be determined by one of the following methods:Pensky Martens Closed Cup test method (ASTM D93, British Standard (BS) EN 22719, BS 2000 Part404, IP 404, International Organization for Standardization (ISO) 2719, Australia Standard/New ZealandStandard (AS/NZS) 2106);Abel Closed Cup test method (BS 2000 Part 170, IP 170, AS/NZS 2106);Abel-Pensky test method (DIN 51755);Tag Closed Cup test method (ASTM D56); orSetaflash Closed Cup test method (ASTM D3278).Closed cup flashpoints may be able to be estimated from open cup measurements. The UN ModelRegulations (para 2.3.1.2) give the UN class 3 Packing Group III limit of 60.5°C, closed cup, as beingequivalent to an open cup value of 65.6°C.The difference between open cup and closed cup values for a substance increases as the flashpointincreases, due to the nature of the two test methods. Therefore, it can be assumed that open cup flashpointvalues of greater than 103°C are correlated with closed cup values in excess of the threshold level of 93°C.Flashpoint limitThe threshold criterion of a flashpoint ≤ 93°C originates from an August 1996 proposal of the UNCETDGsubcommittee advising the IOMC co-ordinating group on flammability to modify the UN Model Regulationscriteria to make it applicable to other aspects of the lifecycle. This was subsequently adopted under theGlobally Harmonized System for Classification and Labelling of Chemicals (United Nations, 2007)Viscous substancesThe UN Model Regulations exempt some specific types of viscous flammable substances from land transportcontrols, but the exemption does not apply to sea and air transport. (See section 2.3.2.5, UN ModelRegulations.)Accordingly, no exemptions are provided in the HSNO Act classification system by reason of viscosity,although, as with other hazards, a substance above the threshold is captured for assessment rather thanautomatically having controls imposed.Screening procedures for mixtures that may be flammable liquidsScreening procedures, involving a theoretical appraisal, can be used to identify the hazard potential ofmixtures that are suspected of having flammable properties instead of experimental determination.January 2012 EPA0109