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RS ISO 1928: 2025
Coal and coke — Determination of gross calorific value

Abstract

This document specifies a method for the determination of the gross calorific value of coal and coke at
constant volume and at the reference temperature of 25 °C in a combustion vessel 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, 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 can also be used; formulae are given for calculating both values.
General principles and procedures for the calibrations and the fuel tests are specified 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 tests using specified types
of calorimeters. Annex E gives examples illustrating some of the calculations. Annex F provides guidance
around safe use, maintenance and testing of the calorimeter combustion vessel.
NOTE Descriptors: solid fuels, coal, coke, tests, determination, calorific value, rules of calculation, calorimetry.

General Information

Code	Classification	Theme	Pages	Publisher	Availability
RS ISO 1928: 2025	ADOPTED ISO STANDARDS	Chemical technology	69	Fifth Edition Jul 2026	Available