Flash Point Testing Methods ASTM D56 and ASTM D93
By: Dana Mladin, Sr. Laboratory Technician & Regulatory Affairs Specialist, email
Consumer chemicals such as glass cleaners, hand sanitizers or surface cleaners containing alcohol (eg. ethanol or IPA), or workplace chemicals such as lubricants, or solvents. Often these products contain one or more chemicals that are flammable and the test will determine if the overall mixture is flammable. This test is designed for substances and mixtures with an expected flash point lower than 93.3°C.
- ASTM D56 – Standard Test Method for Flash Point by Tag Closed Cup Tester and,
- ASTM D93 – Standard Test Methods for Flash Point by Pensky-Martens Closed Cup Tester
Why This Test:
This test determines the lowest temperature at which a solvent will produce an ignitable mixture near its surface. The product flash point is required to determine the chemical classification for shipping and labeling (both workplace labels and retail chemical products labels).
The test report will provide the flash point of a product. Flash point is required for a flammable liquid classification as required under The Globally Harmonized System of Classification and Labeling of Chemicals (GHS) and Consumer Chemicals and Containers Regulations (CCCR).
Flash point is the lowest temperature (corrected to a standard pressure of 101.3 kPa) at which the application of an ignition source causes the vapours of a liquid to ignite under specified test conditions.
Chemical Retail Labels: Consumer Chemicals and Containers Regulations (CCCR) Sections 50 to 52 prescribe ASTM D56 method for solids, paste or gels and liquids with viscosity lower than 5.8 mm2/s at 37.8 C and ASTM D93 for liquids with viscosity higher than 5.8 mm2/s at 37.8 C.
Chemical Workplace Labels: The Globally Harmonized System of Classification and Labeling of Chemicals (GHS) requires that the Flashpoint to be determined by using closed-cup test method.
Two of the methods listed in the GHS purple book are ASTM D56 – Standard Test Method for Flash Point by Tag Closed Cup Tester and ASTM D93 – Standard Test Methods for Flash Point by Pensky-Martens Closed Cup Tester.
ASTM D56 test method covers the determination of the flash point using a Tag Closed Cup Tester (see picture below), of a liquid with a low viscosity.
Using a graduated cylinder, 50 mL of the liquid sample is placed in the cup of the tester Both cylinder and sample being precooled, if necessary, making sure that the sample temperature at the start of the testing is 27 ± 5°C or at least 10°C bellow the expected flash point, whichever is the lowest. The sample is heated at a slow constant rate. The ignition source is applied at specified intervals and the flash point is the lowest temperature at which application of the ignitions source causes the vapour above the specimen to ignite. The sample is deemed to have flashed when a large flame appears and instantaneously propagates itself over the entire surface of the test specimen. The observed flash point shall be corrected for barometric pressure.
The ASTM D93 test method covers the determination of the flash point using a Pensky-Martens Closed Cup Tester (see picture below), of a liquid with a high viscosity or a liquid with tendency to form a surface film under the test conditions.
The procedure is the same as ASTM D56 with few important differences:
- The test uses 75 mL instead 50 mL of sample
- The sample is stirred at specified rates (90 – 120 r/minute for procedure A and 250 r/min ± 10 r/min) and the stirring is stopped only to apply the ignition source
- The starting temperature of the sample shall be 18°C bellow the expected flash point
Determination of an accurate flash point is important for a compliant classification. A flash point erroneously low can trigger supplementary costs related to packaging, shipping and storage. A flash point erroneously high can determine an incorrect less hazardous classification and implicitly wrong or missing hazards warnings making the product very dangerous for everybody involved in manufacturing, shipping, storing and using the product.
If you would like more information about shipping for Transportation of Dangerous Goods (TDG) or Department of Transportation (DOT) or GHS requirements in Canada or the USA, or help choosing the appropriate test method to classify your product, please contact Dell Tech Laboratories for further details. Dell Tech Laboratories is equipped and the staff is trained to perform both ASTM D56 and ASTM D93. Our lab is ISO 17025 accredited. We can help you test and classify your products for GHS, CCCR, or CPSC.
Joe McCarthy, Lab Services Manager