This International Standard specifies a method for the determination of the gross calorific value of a solid fuel at constant volume in an adiabatic, an isothermal, or a static bomb calor imeter.
The result obtained by this method is the gross calorific value of the analysis sample at constant volume, the water of the combustion products being condensed to liquid at the calorimeter temperature. In practice, fuel is burned at constant (atmospheric) pressure and the water is not condensed but is removed, as vapour, with the flue gases. Under these conditions, the operative heat of combustion is the net calorific value of the fuel at constant pressure The net calorific value at constant volume may also be used, tormulae for calculating both values are given.