ISO 18283:2022

INTERNATIONAL ISO
STANDARD 18283
Second edition
2022-03
Coal and coke — Manual sampling
Houille et coke — Échantillonnage manuel
Reference number
ISO 18283:2022(E)
© ISO 2022

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ISO 18283:2022(E)
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© ISO 2022
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ISO 18283:2022(E)
Contents Page
Foreword .v
Introduction .vii
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Establishing a sampling scheme.4
4.1 General . 4
4.1.1 Sampling . 4
4.1.2 Sampling scheme . 5
4.1.3 Parameters . 5
4.1.4 Sampling methods. 5
4.2 Design of the sampling scheme . 6
4.2.1 General . 6
4.2.2 Coal or coke to be sampled and considerations for sampling . 6
4.2.3 Division of lots . 6
4.2.4 Precision of results . 7
4.2.5 Bias of results . 7
4.2.6 Requirements for test samples . 7
4.3 Precision of sampling . 8
4.3.1 General . 8
4.3.2 Precision and total variance . 8
4.3.3 Primary increment variance . 9
4.3.4 Sub-lot variance . 10
4.3.5 Preparation and testing variance . 10
4.3.6 Number of sub-lots and number of increments per sub-lot . 11
4.3.7 Minimum mass of samples for general analysis and determination of total
moisture content .12
4.4 Checking the overall precision for the lot by calculation and selection of sampling
scheme. 15
4.5 Determination of acquired precision by replicate sampling . 15
4.5.1 General .15
4.5.2 Method and calculation .15
4.5.3 Precision obtained using normal sampling scheme . 16
4.6 Size analysis . 16
5 Methods of sampling .17
5.1 General . 17
5.2 Sampling by time interval (time-basis sampling) . 17
5.3 Sampling by mass interval (mass-basis sampling) . 18
5.4 Stratified random sampling . 18
5.4.1 General . 18
5.4.2 Stratified random sampling by time interval . 18
5.4.3 Stratified random sampling by mass interval . 18
5.5 Extracting the increment . 18
5.6 Coal or coke in motion . 19
5.6.1 General . 19
5.6.2 Stopped belt . 19
5.6.3 Falling stream .20
5.6.4 Moving belt .20
5.6.5 Stockpiles (building/reclaiming) . 21
5.6.6 Grabs/front-end loaders . 21
5.6.7 Barges/trucks/railcars/wagons (loading/unloading) .22
5.7 Moisture/common sample .22
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ISO 18283:2022(E)
5.8 Different coals or cokes . 23
5.9 Random selection of increments . 23
6 Sampling equipment .24
6.1 General . 24
6.2 Examples . 25
6.2.1 Ladles. 25
6.2.2 Shovels . 25
6.2.3 Scoops . 25
6.2.4 Probes . 25
6.2.5 Manual cutter . 26
6.2.6 Stopped-belt sampling frame . 26
7 Handling and storage of samples .28
7.1 Sample size . 28
7.2 Time.28
7.3 Divided sample .29
7.4 Containers . .29
7.5 Moisture loss/breakage or degradation .30
7.6 Identification/labelling . 31
8 Sample preparation .31
8.1 General . 31
8.2 Constitution of a sample . 31
8.3 Division . 32
8.3.1 General . 32
8.3.2 Mechanical methods .33
8.3.3 Manual methods . 36
8.4 Reduction .40
8.4.1 General .40
8.4.2 Reduction mills .40
8.5 Mixing . 41
8.6 Air-drying of coal . 41
8.7 Coal — Preparation of test samples . 42
8.7.1 Types of test samples. 42
8.7.2 Preparation of samples for determination of total moisture content . 42
8.7.3 Preparation of samples for general analysis . 43
8.7.4 Common samples . 45
8.7.5 Preparation of size-analysis sample . 47
8.7.6 Preparation of samples for other tests .48
8.7.7 Reserve sample .49
8.8 Coke — Preparation of test samples .49
8.8.1 Types of test samples.49
8.8.2 Preparation of coke samples for determination of total moisture content .50
8.8.3 Preparation of samples for general analysis . 52
8.8.4 Storage .53
8.8.5 Physical test sample . 53
8.8.6 Samples for special properties . 53
8.8.7 Reserve sample . 53
9 Packing and marking of samples .53
10 Sampling report .54
Annex A (informative) Example of calculation of precision, mass of increments,number of
sub-lots and number of increments per sub-lot .55
Annex B (informative) Methods of sampling coal and coke from stationary lots .58
Bibliography .60
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ISO 18283:2022(E)
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 documents 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).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www.iso.org/patents).
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 4,
Sampling.
This second edition cancels and replaces the first edition (ISO 18283:2006), which has been technically
revised. It also incorporates the Technical Corrigendum ISO 18283:2006/Cor.1:2006.
The main changes are as follows:
— Removal of any reference to intermittent sampling. Only continuous sampling is permitted.
— Discussion of the need to eliminate bias prior to discussing precision.
— Deletion of the separate tables on calculated numbers of increments.
— Deletion of the table on reference increment mass.
— Separation of tables for minimum sample masses for coal and coke.
— Removal of the table for reduced minimum sample mass for large sizes of coal and coke.
— Inclusion of manual sampling from a moving conveyor, provided a risk assessment is conducted
at the outset and that this type of sampling is only permitted on a slow-moving belt or at low flow
rates. Furthermore, at higher flow rates, mechanical assistance is necessary to ensure that primary
increments can be collected safely.
— Restriction of the type of probes that can be used.
— Deletion of augers for manual sampling.
— Inclusion of a photograph of a gated riffle.
— Exclusion of sampling of large fuels in excess of the nominal top sizes in Tables 1, 2 and 4, because it
is not practical.
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ISO 18283:2022(E)
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.
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ISO 18283:2022(E)
Introduction
Mechanical sampling from moving streams is the preferred method for sampling coal and coke.
However, often mechanical facilities are not available. Moreover, for sized coal or coke, mechanical
sampling may be a problem because of (size) degradation by the sampling system.
The fundamental requirements of sampling are that all particles of the coal or coke in the lot are
accessible to the sampling instrument and thus have a non-zero chance of being selected, and that each
individual particle of equal mass has an equal probability of being selected and included in the sample.
When sampling manually, conditions are often far from ideal. The methods described in this document
are intended to obtain the most representative sample that can be safely achieved. Manual sampling
should only be applied if no possibility for mechanical sampling exists.
The purpose of taking and preparing a sample of coal or coke is to provide a test sample that, when
analysed, provides test results representative of the lot or sub-lot sampled.
The first stage of sampling, known as primary sampling, is the taking from positions distributed
over the entire lot of an adequate number of coal or coke portions known as primary increments. The
primary increments are then combined into a sample. From this sample, the required number and types
of test samples are prepared by a series of processes jointly known as sample preparation.
In devising a sampling procedure, it is also essential to guard against bias in the taking of increments.
Bias can arise from:
a) incorrect location/timing of increments,
b) incorrect delimitation and extraction of increments,
c) particle size segregation at the point of sampling,
d) loss of integrity of increments after extraction.
Methods for measuring bias are described in ISO 13909-8.
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INTERNATIONAL STANDARD ISO 18283:2022(E)
Coal and coke — Manual sampling
WARNING — This document can involve hazardous materials, operations and equipment, and
does not purport to address all the safety issues associated with its use. It is the responsibility of
the user of this document to establish appropriate health and safety practices.
1 Scope
This document provides the basic terms used in manual sampling of coal and coke and describes the
general principles of sampling. It provides procedures and requirements for establishing a manual
sampling scheme, methods of manual sampling, sampling equipment, handling and storage of samples,
sample preparation and a sampling report, and applies to manual sampling during the transfer of coal
or coke. Guidelines for manual sampling in stationary situations are given in Annex B, but this method
of sampling does not provide a representative test sample and the sampling report shall state this.
This document covers sampling of brown coals and lignites, but does not include sampling from coal
seams, for which guidance is given in ISO 14180. Mechanical sampling of coal and coke is covered in
ISO 13909.
2 Normative references
The following documents are referred to in the text in such a way that some or all of 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 579, Coke — Determination of total moisture
ISO 589, Hard coal — Determination of total moisture
ISO 687, Solid mineral fuels — Coke — Determination of moisture in the general analysis test sample
ISO 13909-8, Hard coal and coke — Mechanical sampling — Part 8: Methods of testing for bias
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological 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/
3.1
air-drying
process of bringing the moisture content of the sample near to equilibrium with the atmosphere in the
area in which further reduction and division of the sample are to take place
Note 1 to entry: Air-drying to equilibrium with the atmosphere applies to coal. Drying of coke is generally to
facilitate sample preparation.
3.2
bias
systematic error that leads to the average value of a series of results being persistently higher or
persistently lower than those that are obtained using a reference sampling method
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ISO 18283:2022(E)
3.3
common sample
sample collected for more than one intended use
3.4
continuous sampling
taking of a sample from every consecutive sub-lot (3.30) so that increments (3.10) are taken at uniform
intervals over the entire lot (3.11) being handled
3.5
cut
see increment (3.10)
3.6
divided increment
part obtained from the division of the increment (3.10) in order to decrease its mass
Note 1 to entry: Such division can be done with or without prior size reduction.
3.7
fixed-mass division
method of sample division in which the mass retained is predetermined and independent of the mass of
the feed
3.8
fixed-ratio division
method of sample division in which the division ratio is predetermined, i.e. the mass of sample retained
is a fixed proportion of the mass of the feed
3.9
general analysis test sample
sample prepared to pass a sieve of nominal size of openings of 212 µm used for the determination of
most chemical and some physical characteristics
3.10
increment
portion of coal or coke extracted in a single operation of the sampling device
Note 1 to entry: Cut is an equivalent term.
3.11
lot
defined quantity of coal or coke for which the quality is to be determined
Note 1 to entry: A lot can be divided into sub-lots.
3.12
manual sampling
extraction of increments (3.10) by human effort
3.13
mass-basis sampling
taking of increments (3.10) whereby the position of each increment (3.10) to be extracted from the
stream of coal or coke is measured by a mass interval of stream flow and the increment (3.10) mass is
...