Classification of flammable liquids under CHIP 4, CLP or UN Recommendations on the Transportation of Dangerous Goods, may allow certain substances to be downrated if they do not sustain combustion.
In the sustained combustibility test, a metal block with a concave depression is heated to 60.5oC. A specified volume of sample is added to the cup and, after a specified time to allow the test substance to heat up, its ability to sustain combustion after application and removal of an ignition source (test flame) is noted.
The test is carried out 3 times using fresh sample and, if sustained combustion is not found, the whole sequence is repeated at a test temperature of 75oC.
Substances that are a mixture of highly flammable and non-flammable components - for example, ethanol and water - may benefit from being tested for sustained combustibility.
