This document specifies a method for the determination of the gross calorific value of a solid biofuel at
constant volume and at the reference temperature 25 °C in a bomb calorimeter calibrated by combustion of
certified benzoic acid.
The result obtained is the gross calorific value of the analysis sample at constant volume with all the water of
the combustion products as liquid water. In practice, biofuels are burned at constant (atmospheric) pressure
and the water is either not condensed (removed as vapour with the flue gases) or condensed. Under both
conditions, the operative heat of combustion to be used is the net calorific value of the fuel at constant
pressure. The net calorific value at constant volume may also be used; formulae are given for calculating both
values.
General principles and procedures for the calibrations and the biofuel experiments are presented in the main
text, whereas those pertaining to the use of a particular type of calorimetric instrument are described in
Annexes A to C. Annex D contains checklists for performing calibration and fuel experiments using specified
types of calorimeters. Annex E gives examples to illustrate some of the calculations.