ISO 1928:2020

Overview

ISO 1928:2020 - "Coal and coke - Determination of gross calorific value" specifies a laboratory method for measuring the gross calorific value (higher heating value) of solid mineral fuels using a combustion-vessel calorimeter. The procedure determines the gross calorific value at constant volume and at the reference temperature of 25 °C, with the calorimeter calibrated by combustion of certified benzoic acid. The standard also provides formulae to calculate net calorific values (operative heat of combustion) and guidance for converting results to different bases.

Key technical topics and requirements

• Scope and principle: Measurement of gross calorific value of coal and coke in a calibrated combustion vessel at constant volume (25 °C reference).
• Calibration: Use of certified benzoic acid as the calibrant; determination of the calorimeter’s effective heat capacity and valid working range.
• Apparatus and reagents: Requirements for calorimeters, thermometers and reagents used in the determination.
• Sample preparation: Procedures for preparing representative analysis samples of solid fuels.
• Measurement procedure: Instructions for assembling the calorimeter, performing combustions, recording temperature rises, and analysing combustion products.
• Calculations: Formulae for gross calorific value at constant volume and for converting to net calorific value at constant pressure or volume.
• Precision and reporting: Repeatability and reproducibility considerations and mandatory test report content.
• Instrument-specific guidance: Annexes A–C describe adiabatic, isoperibol/static-jacket, and automated calorimeters; Annex D offers checklists; Annex E gives worked calculation examples; Annex F provides safety, maintenance and testing guidance for combustion vessels.

Practical applications

• Quality control and specification of coal and coke used in power generation, metallurgy and industrial heating.
• Contract verification of energy content for fuel procurement and trade.
• Fuel characterization for process optimization in power plants, coking plants, and industrial boilers.
• Laboratory accreditation and regulatory compliance where standardized calorific-value measurement is required.
• Research and development on solid fuel performance, combustion efficiency, and emissions modelling.

Who should use ISO 1928:2020

• Analytical laboratories performing calorific-value testing.
• Coal and coke producers and traders verifying product energy content.
• Power utilities, steel and cement plants assessing fuel quality.
• QA/QC engineers, procurement specialists, and regulatory agencies requiring standardized test methods.

Related standards

ISO 1928:2020 references other ISO standards for thermometers, sampling and moisture determination (e.g., ISO 651, ISO 13909‑4, ISO 17247). Users should consult these related documents for complementary requirements in sampling, moisture analysis and thermometer specifications.

Keywords: ISO 1928:2020, gross calorific value, coal, coke, calorimetry, combustion vessel calorimeter, benzoic acid calibration, net calorific value, solid mineral fuels, calorimeter calibration.