ASTM D3278-21 Standard Test Methods for Flash Point of Liquids by Small-Scale Closed-Cup Apparatus

The American Society for Testing and Materials (ASTM) standard "ASTM D3278-21 Standard test methods for flash point of liquids by small-scale closed-cup apparatus" describes test methods that use a small-scale closed-cup apparatus to determine whether a material flashes at a specified temperature (Method A flash/no flash) or the lowest terminal temperature at which a material flashes (Method B). These test methods are applicable to paints, enamels, lacquers, varnishes, solvents, and related products having a flash point between 0 degrees and 110 degrees and a viscosity of less than 25 mm15.000/s at 2 degrees.

Testing at higher or lower temperatures is possible but the sensitivity has not been determined. More viscous materials may be tested in accordance with the annex of the standard (Annex A4). Organic peroxides may be tested in accordance with the annex of the standard describing the applicable safety precautions (Annex A59.

The U.S. Department of Labor (OSHA, Hazard Communications), the U.S. Department of Transportation, and the U.S. Environmental Protection Agency (EPA) accept the ASTM D3278-21 standard in their published regulations as one of several acceptable methods for determining the flash point of liquids.

For the purposes of this standard, the following terms and definitions apply:

• Equilibrium, in flash point test methods, refers to the condition in which the vapour above the test sample and the test sample are at the same temperature when the ignition source is applied. This condition may not be fully achieved in practice, as the temperature may not be uniform across the test sample and the test cover and shutter on the apparatus may be colder or hotter.
• The flash point is adjusted in test methods to account for changes in atmospheric pressure from 101,3 kPa, the lowest temperature of the test sample at which application of an ignition source under specified test conditions will cause the vapours of the test sample to ignite.

When performing Method A (flash/no flash testing), a 2 mL test sample is introduced with a syringe into the test vessel of the selected device, which has been set and maintained at the specified test temperature. After one minute, an ignition source is applied and a determination is made as to whether a flash has occurred.

When Method B (finite or true flash point test) is applied, this method essentially repeats Method A several times and determines the flash point iteratively by changing the test temperature and test sample several times. A 2 mL test sample is introduced into the test vessel of the selected device held at the expected flash point. After one minute, an ignition source is applied and a determination is made whether a flash has occurred. The test sample is removed from the test vessel, the test vessel and lid are cleaned, and the test temperature is set 5 degrees lower or higher, depending on whether a flash has previously occurred. A new test sample is introduced and tested. This procedure is repeated until the flash point is determined to within 5 degrees. The procedure is then repeated at 0,5 degree intervals until the flash point is determined to the nearest 0,5 degree. A second determination is made in this manner and the average of the two determinations is recorded as the flash point.

Flash point measures the response of a test sample to heat and an ignition source under controlled laboratory conditions. It is only one of a number of properties that must be considered when assessing the overall flammability hazard of a material. Flash point is used by regulatory bodies to identify and classify flammable and combustible materials in transportation and safety regulations. The specific regulation should be consulted for precise definitions of these classes. Flash point may indicate the possible presence of highly volatile and flammable impurities or contaminants in a given liquid, such as the presence of residual solvents in solvent-refined drying oils.

These equilibrium flash point test methods use a smaller sample (56 mL) and a shorter test time (22 minute) than traditional non-equilibrium test methods, such as the test methods described in “ASTM D93-20 Standard test method for flash point with label-closed tester” and “ASTM D2-1 Standard test methods for flash point with Pensky-Martens closed-cup tester.”

The test methods described in “ASTM D3828-07 Standard test methods for flash point by small-scale closed-cup tester”, “ASTM D8174-18 Standard test method for determining finite flash point of liquid wastes by small-scale closed-cup tester” and “ISO 3679 Determination of flash point - Flash-nonflash and flash point method by small-scale closed-cup tester” are similar and use the same apparatus.

Our organization has a strong staff that closely follows the developments in the world in the field of science and technology and constantly improves itself. Among the numerous test, measurement, analysis and evaluation studies provided for businesses in various sectors, there are also test services in accordance with the standard "ASTM D3278-21 Standard test methods for flash point of liquids with small-scale closed container apparatus".