ISO 1953
(Main)Coal — Size analysis by sieving
Coal — Size analysis by sieving
ISO 1953:2015 specifies reference methods for the size analysis of coal by manual sieving (wet or dry), using test sieves of aperture sizes between 125 mm and 45 μm. A guide to sampling is given in Annex A. This International Standard is applicable to all hard coals. It is not applicable to coke or other manufactured fuels. In the case of pulverized coal which has been ground so that a high proportion passes through the test sieve of smallest aperture size, the methods described in this International Standard will determine only the percentage oversize.
Charbon — Analyse granulométrique par tamisage
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Standards Content (Sample)
FINAL DRAFT
International
Standard
ISO/FDIS 1953
ISO/TC 27/SC 1
Coal — Size analysis by sieving
Secretariat: SA
Charbon — Analyse granulométrique par tamisage
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2025-07-09
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Reference number
ISO/FDIS 1953:2025(en) © ISO 2025
FINAL DRAFT
ISO/FDIS 1953:2025(en)
International
Standard
ISO/FDIS 1953
ISO/TC 27/SC 1
Coal — Size analysis by sieving
Secretariat: SA
Charbon — Analyse granulométrique par tamisage
Voting begins on:
Voting terminates on:
RECIPIENTS OF THIS DRAFT ARE INVITED TO SUBMIT,
WITH THEIR COMMENTS, NOTIFICATION OF ANY
RELEVANT PATENT RIGHTS OF WHICH THEY ARE AWARE
AND TO PROVIDE SUPPOR TING DOCUMENTATION.
© ISO 2025
IN ADDITION TO THEIR EVALUATION AS
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO
LOGICAL, COMMERCIAL AND USER PURPOSES, DRAFT
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
INTERNATIONAL STANDARDS MAY ON OCCASION HAVE
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TO BE CONSIDERED IN THE LIGHT OF THEIR POTENTIAL
or ISO’s member body in the country of the requester.
TO BECOME STAN DARDS TO WHICH REFERENCE MAY BE
MADE IN NATIONAL REGULATIONS.
ISO copyright office
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CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland Reference number
ISO/FDIS 1953:2025(en) © ISO 2025
ii
ISO/FDIS 1953:2025(en)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and Definitions . 1
4 Apparatus . 1
4.1 For all methods .2
4.2 For dry sieving .2
4.3 For wet sieving.2
5 Sampling and preparation . 3
5.1 Sampling .3
5.2 Preparation .3
5.3 Division of the gross sample, other than wet coal of less than 4 mm .4
5.4 Division of the gross sample of wet coal less than 4 mm.4
5.5 Drying of test sample for sizing .4
5.6 Equilibration of test samples dried at enhanced temperature.4
5.7 Equilibration periods .4
6 Procedure . 4
6.1 General .4
6.2 Dry sieving .5
6.2.1 Test sample of maximum particle size greater than 22,4 mm .5
6.2.2 Sample of maximum particle size between 4 mm and 22,4 mm — Manual method .5
6.2.3 Sample of maximum particle size less than 4 mm — Manual method .6
6.2.4 Sample of maximum particle size between 4 mm and 22,4 mm; minus 4 mm —
Mechanical method .7
6.3 Wet sieving .7
7 Expression of results . 8
7.1 Calculation .8
7.2 Graphical presentation .8
8 Test report . 8
Annex A (informative) Guide to sampling .13
Annex B (informative) Example of removal by wet sieving of fine material from a sample having
a maximum particle size less than 4 mm . 14
Annex C (informative) .15
iii
ISO/FDIS 1953:2025(en)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out through
ISO technical committees. Each member body interested in a subject for which a technical committee
has been established has the right to be represented on that committee. International organizations,
governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely
with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are described
in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types
of ISO document should be noted. This document was drafted in accordance with the editorial rules of the
ISO/IEC Directives, Part 2 (see www.iso.org/directives).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent
rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a)
patent(s) which may be required to implement this document. However, implementers are cautioned that
this may not represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions
related to conformity assessment, as well as information about ISO's adherence to the World Trade
Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 27, Coal and coke, Subcommittee SC 1, Coal
preparation: Terminology and performance.
This fourth edition cancels and replaces the third edition (ISO 1953:2015), which has been technically
revised.
The main changes are as follows:
— size analysis of coal greater than 90 mm was removed from Table 1;
— instructions provided for air drying and equilibrating different coals (examples are high rank coal, low
rank coal and lignite). Advice provided for air drying at enhanced temperatures has also been added;
— additional test report items were included;
— Gy’s formula was not suitable to determine minimum masses for sizing at various nominal top sizes and
for precision calculations in Table 1 and has been removed.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
iv
ISO/FDIS 1953:2025(en)
Introduction
Size analysis involves the separation of a sample of coal into size fractions with defined limits. In the methods
described in this document the results are expressed in terms of the percentage mass of coal remaining
on sieves of different aperture sizes. This information can be of use in several applications, including the
following:
a) determining the size analysis of coals exported and imported internationally
b) assessing the yields of products from run-of-mine coals;
c) providing design data for coal preparation plants;
d) checking that products from screening plants are within the required limits;
e) assessing the performance of coal-crushing plants;
f) selecting coals for processes and equipment.
v
FINAL DRAFT International Standard ISO/FDIS 1953:2025(en)
Coal — Size analysis by sieving
1 Scope
This document specifies reference methods for the size analysis of coal by manual sieving (wet or dry), using
test sieves of aperture sizes between 90 mm and 45 μm. A guide to sampling is given in Annex A.
This document is applicable to all coals. It is not applicable to coke.
In the case of pulverized coal which has been ground so that a high proportion passes through the test
sieve of the smallest aperture size, the methods of this document determine only the mass fraction oversize
expressed as a percent.
2 Normative references
The following documents are referred to in the text in such a way that some or all their content constitutes
requirements of this document. For dated references, only the edition cited applies. For undated references,
the latest edition of the referenced document (including any amendments) applies.
ISO 1213-1, Coal and coke — Vocabulary — Part 1: Terms relating to coal preparation
ISO 1213-2, Coal and coke — Vocabulary — Part 2: Terms relating to sampling, testing and analysis
ISO 3310-1, Test sieves — Technical requirements and testing — Part 1: Test sieves of metal wire cloth
ISO 3310-2, Test sieves — Technical requirements and testing — Part 2: Test sieves of perforated metal plate
ISO 13909-2, Coal and coke — Mechanical sampling — Part 2: Sampling of coal from moving streams
ISO 13909-4, Coal and coke — Mechanical sampling — Part 4: Preparation of test samples of coal
ISO 13909-7, Coal and coke — Mechanical sampling — Part 7: Methods for determining the precision of sampling,
sample preparation and testing
ISO 18283, Coal and coke — Manual sampling
3 Terms and Definitions
For the purposes of this document, the terms and definitions
...
ISO TC 27/SC 01
Date: 2025-05-09
ISO/FDIS 1953:2025(en)
ISO/TC 27/SC 1
Secretariat: SA
Date: 2025-06-24
Coal — Size analysis by sieving
Copyright notice
ThisCharbon — Analyse granulométrique par tamisage
FDIS stage
ISO/FDIS 1953:2025(en)
© ISO document is a Draft International Standard and is copyright-protected by ISO. Except as permitted under 2025
All rights reserved. Unless otherwise specified, or required in the applicable lawscontext of the user's country, neither
its implementation, no part of this ISO draft nor any extract from itpublication may be reproduced, stored in a retrieval
system or transmitted or utilized otherwise in any form or by any means, electronic, or mechanical, including
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Requests for permission to reproduce should be addressed to . Permission can be requested from either ISO at the
address below or ISO'sISO’s member body in the country of the requester.
ISO copyright office
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CH-12111214 Vernier, Geneva 20
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Reproduction may be subject to royalty payments or a licensing agreement.
Violators may be prosecuted.
Published in Switzerland
iii
ISO/FDIS 1953:2025(en)
Contents Page
Foreword . v
Introduction . vi
1 Scope . 1
2 Normative references . 1
3 Terms and Definitions . 1
4 Apparatus . 1
5 Sampling and preparation . 3
6 Procedure . 5
7 Expression of results . 9
8 Test report . 10
Annex A (informative) Guide to sampling . 17
Annex B (informative) Example of removal by wet sieving of fine material from a sample having
a maximum particle size less than 4 mm . 18
Annex C (informative) . 19
Annex C (informative) Scoop and bump plate division technique . 18
iv
ISO/FDIS 1953:2025(en)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out through
ISO technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are described
in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types of
ISO document should be noted. This document was drafted in accordance with the editorial rules of the
ISO/IEC Directives, Part 2 (see www.iso.org/directives).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent rights
in respect thereof. As of the date of publication of this document, ISO had not received notice of (a) patent(s)
which may be required to implement this document. However, implementers are cautioned that this may not
represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions
related to conformity assessment, as well as information about ISO's adherence to the World Trade
Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 27, Coal and coke, Subcommittee SC 1, Coal
preparation: Terminology and performance.
This fourth edition cancels and replaces the third edition (ISO 1953:2015), which has been technically revised.
The main changes are as follows:
— — size analysis of coal greater than 90 mm was removed from Table 1Table 1; ;
— — instructions provided for air drying and equilibrating different coals (examples are high rank coal, low
rank coal and lignite). Advice provided for air drying at enhanced temperatures has also been added;
— — additional test report items were included;
— — Gy’s formula was not suitable to determine minimum masses for sizing at various nominal top sizes
and for precision calculations in Table 1Table 1 and has been removed.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
v
ISO/FDIS 1953:2025(en)
Introduction
Size analysis involves the separation of a sample of coal into size fractions with defined limits. In the methods
described in this document the results are expressed in terms of the percentage mass of coal remaining on
sieves of different aperture sizes. This information can be of use in several applications, including the
following:
a) determining the size analysis of coals exported and imported internationally
b) assessing the yields of products from run-of-mine coals;
c) providing design data for coal preparation plants;
d) checking that products from screening plants are within the required limits;
e) assessing the performance of coal-crushing plants;
f) selecting coals for processes and equipment.
vi
ISO/FDIS 1953:2025(en)
Coal — Size analysis by sieving
1 Scope
This document specifies reference methods for the size analysis of coal by manual sieving (wet or dry), using
test sieves of aperture sizes between 90 mm and 45 μm. A guide to sampling is given in Annex AAnnex A.
This document is applicable to all coals. It is not applicable to coke.
In the case of pulverized coal which has been ground so that a high proportion passes through the test sieve
of the smallest aperture size, the methods of this document determine only the mass fraction oversize
expressed as a percent.
2 Normative references
The following documents are referred to in the text in such a way that some or all their content constitutes
requirements of this document. For dated references, only the edition cited applies. For undated references,
the latest edition of the referenced document (including any amendments) applies.
ISO 1213 part--1, Coal and coke — Vocabulary — Part 1: Terms relating to coal preparation
ISO 1213 part--2, Coal and coke — Vocabulary — Part 2: Terms relating to sampling, testing and analysis
ISO 3310 part--1, Test sieves — Technical requirements and testing — Part 1: Test sieves of metal wire cloth
ISO 3310 part--2, Test sieves — Technical requirements and testing — Part 2: Test sieves of perforated metal
plate
ISO 13909 part-2, Hard coalCoal and coke — Mechanical sampling — Part 2: Sampling of coal from moving
streams
ISO 13909 part-4, Hard coalCoal and coke — Mechanical sampling — Part 4: Preparation of test samples of coal
ISO 13909 part-7, Hard coalCoal and coke — Mechanical sampling — Part 7: Methods offor determining the
precision of sampling, sample preparation and testing
ISO 18283, Coal and coke — Manual sampling
3 Terms and Definitions
For the purposes of this document, the terms and definitions given in ISO 1213--1 and ISO 1213--2 apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— — ISO Online browsing platform: available at https://www.iso.org/obp
— — IEC Electropedia: available at https://www.electropedia.org/
4 Apparatus
The usual laboratory apparatus and the following shall be used.
ISO/FDIS 1953:2025(en)
4.1 For all methods
Test sieves,
a) a) shall be exclusively round-holed or exclusively square-holed screens in accordance with
ISO 3310-part -1 or ISO 3310- part -2;
b) b) the recommended series of test sieves for general purposes is 125 mm, 90 mm, 75 mm, 63 mm,
50 mm, 45 mm, 31,5 mm, 22,4 mm, 16 mm, 11,2 mm, 8 mm, 5,6 mm, 4 mm, 2 mm and 1 mm nominal
aperture sizes. With square hold-sieves, each side in mm is the recommended series. With round hole
sieves, the diameter of the sieve in mm is the recommended series. If this series is inadequate for the
sizing of graded coals, sieves from the supplementary sizes 100 mm, 80 mm, 40 mm, 25 mm, 20 mm,
12,5 mm, 10 mm and 6,3 mm may be included;
c) c) for samples in the range 90 mm x× 75 mm, single square-hole or round-hole gauges of the
required dimensions may be used for the larger pieces. Sizes greater than 90 mm are not covered by this
Standarddocument;
d) d) test sieves of nominal aperture size 4 mm and less should be of metal wire cloth; the
recommended series of nominal aperture sizes is 4 mm, 2,8 mm, 2 mm, 1,4 mm, 1 mm, 710 μm, 500 μm,
355 μm, 250 μm, 180 μm, 125 μm, 90 μm, 63 μm and 45 μm;
e) e) when a complete size analysis is required, it is recommended subject to the range of sieve
aperture sizes available, that the mass of coal in any size fraction doesshould not exceed 30 % of the total
mass of sample being sieved, subject to the range of sieve aperture sizes available;
f) f) the largest aperture size sieve should be that on which not more than 5 % mass fraction of the
sample is retained, and the smallest aperture size sieve should be that through which not more than 5 %
mass fraction of the sample passes;
g) g) all sieves shall be checked at least once per year by the methods described in ISO 3310--1 and
ISO 3310--2, to ensure that the aperture dimensions are within the specified tolerances. All screens less
than 0,5 mm shall be visually checked for holes before size analysis commences. Worn, holed or damaged
sieves can give rise to serious errors in size analysis and shall be discarded.
Receivers, for collecting material passing through the sieves.
Weighing scale, capable of measuring the mass of the sample sieved by weighing to the nearest 0,1 %.
Trays, smooth, of non-corrodible material, of at least 400 mm × 400 mm, depending on the mass sample and
number of analyses required
Watch- or clock-glasses.
4.2 For dry sieving
Lids, to fit the test sieves.
Flat brush, for cleaning the sieves and for brushing dust from the trays.
Hardwood block, about 150 mm long with a 10 mm × 10 mm cross-section, for tapping the sieves.
Shovel or scoop.
Bump plate thin piece of square steel (5 mm thick) just larger than the dimensions of the scoop to aid sample
collection with a scoop. (Figure C.1(Annex C Figure 3))
ISO/FDIS 1953:2025(en)
Vibratory sieve shaker for mechanical sieving.
4.3 For wet sieving
Pressure filter
Buchner funnel and Buchner flask.
Filter paper.
Oven, capable of being controlled to ±5 °C in the range 30 °C to 110 °C.
5 Sampling and preparation
5.1 Sampling
a) a) the gross sample shall be taken in accordance with ISO 13909-part 2 or ISO 18283, for both
dry and wet sizing;
b) b) it is recommended that the minimum mass of the gross sample should be at least twice the
mass indicated for the test sample for sizing in Table 1Table 1 so that a reserve test sample for sizing is
retained;
c) c) if a coal sample is received from a third party-source for size analysis and the mass of the
sample does not meet the minimum mass for the test sample for sizing in Table 1Table 1 then the mass
received shall be clearly indicated on the test report (see Clause 8Clause 8).).
Table 1 — Minimum mass of sample for size analysis
Minimum mass for a Minimum mass for a
Nominal top size of coal
precision of 1 % precision of 2 %
mm kg kg
90 1 500 400
75 950 250
63 500 125
50 280 70
45 200 50
38 130 30
31,5 65 15
22,4 25 6
16,0 8 2
11,2 3 0,70
10,0 2 0,50
8,0 1 0,25
5,6 0,50 0,25
4,0 0,25 0,25
2,8 0,25 0,25
2,0 0,25 0,25
ISO/FDIS 1953:2025(en)
Minimum mass for a Minimum mass for a
Nominal top size of coal
precision of 1 % precision of 2 %
mm kg kg
1,0 0,25 0,25
< 0,5 0,25 0,25
NoteNOTE 1 to Table 1: The masses
...
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