This International Standard specifies a method for the determination of the gross heat of combustion (QPCS) of products at constant volume in a bomb calorimeter. This method is intended to be applied to solid products. Note: liquids shall be tested with similar equipment and using conditions described in ASTM D240 [1], as described in IEC 61039 [2] using ISO 1928 [3] test equipment Annex A describes the calculation of the net heat of combustion (QPCI) when required. Information on the precision of the test method is given in Annex B.