This test method is intended for use in cases where an experimental determination of heat of combustion is not available and cannot be made conveniently, and where an estimate is considered satisfactory. It is not intended as a substitute for experimental measurement of heat of combustion.

1.1 This test method covers the estimation of the gross and net heat of combustion in SI units, megajoules per kilogram, of petroleum fuels from the fuel density, sulfur, water, and ash content.

Note 1—The equation for estimation of net and gross heat of combustion used in this method were originally published by the NIST Publication No. 97.

1.2 This test method is especially useful for estimating, using a minimum number of tests, the heat of combustion of burner and diesel fuels for which it is not usually critical to obtain very precise heat determinations.

Note 2—More accurate estimation methods are available for aviation fuels (Test Methods D1405, D4529,and D3338). However, those estimation methods require additional tests to those required in this test method.

1.3 This test method is purely empirical (Note 1). It is applicable only to liquid hydrocarbon fuels derived by normal refining processes from conventional crude oil that conform to the requirements of specifications for petroleum fuels as described in Note 3. This test method is valid for those fuels in the density range from 750 to 1000 kg/m³ and those that do not contain an unusually high aromatic content. High aromatic content fuels will not normally meet fuel specification criteria.