1.1 This test method covers the determination of the amount of carbon residue (see Note 1) formed after evaporation and pyrolysis of petroleum materials under certain conditions and is intended to provide some indication of the relative coke forming tendency of such materials. 1.2 The test results are equivalent to the Conradson Carbon Residue test (see Test Method D 189). This procedure is a modification of the original method and apparatus for carbon residue of petroleum materials, w