This standard specifies the method principles and basic requirements for the measurement of carbon, hydrogen and nitrogen elements in fuels by the high-temperature combustion-infrared and thermal conductivity combined determination method and the high-temperature combustion-adsorption analysis-thermal conductivity method. This standard is applicable to the rapid instrumental determination of carbon, hydrogen, and nitrogen elements and the calculation of oxygen elements in solid mineral fuels (including coal, semi-coke, petroleum coke, etc.) and biomass fuels (including straw, tree branches, straw, etc.). Instrumental rapid determination of carbon, hydrogen, and nitrogen elements in liquid fuels can also refer to this standard.