This test apparatus is used for the determination of the amount of carbon residue left after evaporation and pyrolysis of an oil, and it is intended to provide some indication of relative coke- forming propensity. This test method is generally applicable to relatively nonvolatile petroleum products which partially decompose on distillation at atmospheric pressure. This test method also covers the determination of carbon residue on 10% (V/V) distillation residues. The apparatus is specifically used for calculating carbon residue from the sample. The test is conducted in accordance with ASTM D 524 / IP 14/ IS 1448).