DIN EN ISO 18125:2017-08

This document has been prepared by Technical Committee ISO/TC 238 "Solid biofuels" in collaboration with Technical Committee CEN/TC 335 "Solid biofuels", the secretariat of which is held by SIS. This document specifies a method for the determination of the gross calorific value of a solid biofuel at constant volume and at a reference temperature 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. The responsible German standardization committee is Working Committee NA 062-05-82 AA "Biogene Festbrennstoffe" ("Solid biofuels") at DIN Standards Committee Materials Testing (NMP).