BS EN ISO 18125:2017 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.


Cross References:
ISO 1770
ISO 14780:2017
ISO 1771
ISO 652
ISO 651
ISO 16559:2014 ED1
ISO 16994:2016
ISO 18134-3:2015
ISO 18135:2017
ISO 16948:2015 ED1
ISO 18122:2015
ISO 1928:2009 Ed 3
ISO 18134-2:2017
ISO 10304-1:2007 Ed 2
ISO 18134-1:2015
ISO 17225-1:2014 ED1
ISO 16993:2016


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