ISO 1928-2025 PDF

Full title and description

St ISO 1928-2025 — Coal and coke — Determination of gross calorific value. This standard specifies a laboratory method (bomb calorimetric) for determining the gross calorific value (higher heating value) of solid mineral fuels such as coal and coke, and gives the procedures and formulae required to calculate net calorific values and to report results.

Abstract

ISO 1928:2025 provides a standardized procedure for measuring the gross calorific value of coal and coke by combustion in a bomb calorimeter calibrated with certified benzoic acid. The document covers sample preparation, apparatus and reagent requirements, calibration and test procedures, corrections and calculations (including conversion to net calorific value), reporting, and informative annexes for instrument-specific guidance and safety.

General information

• Status: Published / Active.
• Publication date: 13 August 2025.
• Publisher: International Organization for Standardization (ISO).
• ICS / categories: 75.160.10 (Solid fuels).
• Edition / version: Edition 5.0 (ISO 1928:2025).
• Number of pages: 61.

Scope

This standard applies to the determination of the gross calorific value (higher heating value) of samples of coal and coke at constant volume using a bomb calorimeter calibrated by combustion of certified benzoic acid. It includes requirements for apparatus, reagents and sample preparation, description of calibration and measurement procedures, temperature corrections (reference temperature 25 °C), formulae to convert gross calorific value to net calorific value (constant-pressure and constant-volume bases), guidance on uncertainty and reporting, and informative annexes addressing different calorimeter types and safety/maintenance considerations.

Key topics and requirements

• Principle of measurement: determination of gross calorific value at constant volume using a bomb calorimeter.
• Calorimeter calibration using certified benzoic acid and calculation of effective heat capacity.
• Sample preparation, representative sampling and drying requirements for solid mineral fuels.
• Test procedure: charge preparation, ignition, temperature-rise measurement, corrections and repeat runs.
• Conversions and formulae to calculate net calorific value (constant pressure/volume) and reference-temperature adjustments.
• Quality control: repeatability/reproducibility guidance, calibration checks and reporting requirements.
• Instrument-specific annexes: guidance for adiabatic, isoperibol and automated calorimeters; examples and checklists.
• Safety, maintenance and safe handling of the combustion vessel and oxygen supply (informative annex).

Typical use and users

Used by analytical and testing laboratories, coal and coke producers, utilities, fuel traders, research institutes and regulatory bodies to determine heating values for product specification, fuel quality control, commercial transactions, energy calculations and emissions/combustion modeling. Laboratories rely on the standard to ensure comparability of calorific-value determinations between organizations and across jurisdictions.

Related standards

ISO 1928:2025 revises and replaces earlier editions of ISO 1928 (for example ISO 1928:2009 which was withdrawn). Related and complementary documents include ISO standards for calorific-value determination of other fuel types (for example ISO 18125 for solid biofuels) and recognized alternative test methods such as ASTM D5865 (gross calorific value of coal and coke).

Keywords

ISO 1928, calorific value, gross calorific value, higher heating value, net calorific value, bomb calorimeter, coal, coke, solid fuels, fuel testing, calorimetry, sample preparation, calibration.

FAQ

Q: What is this standard?

A: ISO 1928:2025 is the international standard that specifies the laboratory method for determining the gross calorific value of coal and coke using a bomb calorimeter, and for calculating net calorific values.

Q: What does it cover?

A: It covers apparatus and reagent requirements, calibration procedures (benzoic acid calibration), sample preparation, the measurement procedure, corrections and calculations to convert gross to net calorific values, uncertainty and reporting guidance, and informative annexes for different calorimeter types and safety issues.

Q: Who typically uses it?

A: Analytical laboratories, coal and coke producers, utilities and power plants, fuel traders, research organizations and regulators use the standard for product specification, quality control, commercial measurement and energy accounting.

Q: Is it current or superseded?

A: ISO 1928:2025 is the current published edition that supersedes earlier editions (for example the 2009 edition which was withdrawn).

Q: Is it part of a series?

A: ISO 1928 is part of the body of ISO and national standards covering methods of analysis for solid fuels (work of ISO/TC 27/SC 5). Other related ISO standards cover calorific-value measurement for different fuel types and complementary test methods.

Q: What are the key keywords?

A: Key keywords are: gross calorific value, higher heating value (GCV/HHV), net calorific value (NCV), bomb calorimeter, coal, coke, fuel testing, calibration, benzoic acid, ISO 1928.