ISO 2950:2025

Brown coals and lignites - Classification by types on the basis of total moisture mass fraction and tar yield

This document establishes a classification of brown coals and lignites by types on the basis of total moisture mass fraction and tar yield.

Charbons bruns et lignites — Classification en types, d'après la fraction massique d'humidité totale et le rendement en goudron

General Information

• Status: Published
• Publication Date: 22-Oct-2025
• ICS: 73.040 - Coals
• Technical Committee: ISO/TC 27/SC 5 - Methods of analysis
• Drafting Committee: ISO/TC 27/SC 5/WG 7 - Brown coals and lignites
• Current Stage: 6060 - International Standard published
• Start Date: 23-Oct-2025
• Due Date: 21-Aug-2026
• Completion Date: 23-Oct-2025

Relations

• Revises: ISO 2950:1974 - Brown coals and lignites - Classification by types on the basis of total moisture content and tar yield
• Effective Date: 24-Aug-2024

Overview

ISO 2950:2025 - Brown coals and lignites - Classification by types on the basis of total moisture mass fraction and tar yield establishes a standardized system to classify brown coals and lignites by two measured properties: total moisture mass fraction (ash‑free basis) and tar yield (dry, ash‑free basis). The document defines classes and groups, prescribes a two‑digit coding system for types, and references the test methods required to determine the classification indices.

Key topics

• Classification principle: Types are defined by the combination of total moisture (ash‑free) and tar yield (dry, ash‑free).
• Class division (moisture): Six classes based on total moisture mass fraction on the ash‑free basis:
  • Class 1: ≤ 20 %
  • Class 2: > 20 to 30 %
  • Class 3: > 30 to 40 %
  • Class 4: > 40 to 50 %
  • Class 5: > 50 to 60 %
  • Class 6: > 60 to 70 %
• Group division (tar yield): Five groups based on tar yield on the dry, ash‑free basis:
  • Group 0: ≤ 10 %
  • Group 1: > 10 to 15 %
  • Group 2: > 15 to 20 %
  • Group 3: > 20 to 25 %
  • Group 4: > 25 %
• Coding system: A two‑digit code identifies type - first digit = class (moisture), second digit = group (tar). Example: code 34 indicates class 3, group 4.
• Testing methods (normative references):
  • ISO 5068-1 for total moisture (run‑of‑mine coal)
  • ISO 647 for tar yield (low temperature distillation)
  • ISO 1171 for ash determination
  • ISO 5068-2 for moisture in analysis samples

Applications

ISO 2950:2025 is practical for organizations that need a consistent, internationally recognized way to describe brown coal and lignite types. Typical users include:

• Coal producers and mine operators for product characterization and marketing
• Analytical laboratories performing coal quality testing and reporting
• Power plants, fuel preparers and industrial users assessing feedstock properties
• Regulators and commodity traders requiring standardized coal type descriptors
• Researchers and technical consultants working on coal utilization and combustion studies

The standard supports comparability of coal quality data, specification of supply contracts, and informed decisions on handling, drying, and utilization based on moisture and tar characteristics.

Related standards

• ISO 5068-1 - Brown coals and lignites - Determination of total moisture (indirect gravimetric)
• ISO 5068-2 - Determination of moisture in the analysis sample
• ISO 647 - Determination of tar, water, gas and coke residue by low temperature distillation
• ISO 1171 - Coal and coke - Determination of ash

Keywords: ISO 2950:2025, brown coals, lignites, classification, total moisture mass fraction, tar yield, dry ash‑free, coal testing, ISO 5068, ISO 647, ISO 1171.

Standards Content (Sample)

International
Standard
ISO 2950
Second edition
Brown coals and lignites —
2025-10
Classification by types on the basis
of total moisture mass fraction and
tar yield
Charbons bruns et lignites — Classification en types, d'après la
fraction massique d'humidité totale et le rendement en goudron
Reference number
© ISO 2025
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
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Published in Switzerland
ii
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 1
5 Classification indices . 2
5.1 Division of brown coals and lignites into classes .2
5.2 Division of brown coals and lignites into groups .2
5.3 Code numbers .2
5.4 Classification of brown coals and lignites by types .2
6 Methods of testing . 3
6.1 Determination of total moisture mass fraction .3
6.2 Determination of tar yield .3
6.3 Determination of ash .3
6.4 Determination of moisture in the analysis sample .3

iii
Foreword
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