This standard is concerned with the determination of the amount of carbon residue in the range of 0.01% to 30% m/m, (carbonaceous residue) left after evaporation and pyrolysis of an oil, and is intended to provide some indication of relative coke-forming propensities. This test method is generally applicable to relatively nonvolatile petroleum products which partially decompose on distillation at atmospheric pressure. Petroleum products containing ash-forming constituents will have an erroneously high carbon residue, depending upon the amount of ash formed.