scope:

Specifies methods for the calculation of the superior calorific value, inferior calorific value, density, relative density and Wobbe index of dry natural gases, natural gas substitutes and other combustible gaseous fuels, when the composition of the gas by mole fraction is known. The methods prodive a means of calculating the properties of the gas mixture at commonly used metric reference conditions. The methods of calculation require values for various physical properties of the pure components; these values are provided in tables and their sources are identified. Methods are given for estimating the precision of calculated properties. The methods of calculation of the values of properties on either a molar or mass basis are applicable to any dry natural gas, natural gas substitute or other combustible fuel which is normally gaseous. For the calculation of the values of properties on a volumetric basis, the methods are restricted to gases consisting preponderantly of methane (not less than 0,5 mole fraction).