ISO 13909-2:2016

INTERNATIONAL ISO
STANDARD 13909-2
Second edition
2016-07-01
Hard coal and coke — Mechanical
sampling —
Part 2:
Coal — Sampling from moving streams
Houille et coke — Échantillonnage mécanique —
Partie 2: Charbon — Échantillonnage en continu
Reference number
©
ISO 2016
© ISO 2016, Published in Switzerland
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ii © ISO 2016 – All rights reserved

Contents Page
Foreword .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Establishing a sampling scheme . 1
4.1 General . 1
4.2 Design of the sampling scheme . 2
4.2.1 Material to be sampled . 2
4.2.2 Division of lots . 2
4.2.3 Basis of sampling . 2
4.2.4 Precision of sampling . 2
4.2.5 Bias of sampling. 3
4.3 Precision of results . 3
4.3.1 Precision and total variance . 3
4.3.2 Primary increment variance . 4
4.3.3 Preparation and testing variance . 4
4.3.4 Number of sub-lots and number of increments per sub-lot . 4
4.4 Minimum mass of sample . 7
4.5 Mass of primary increment . 9
4.6 Size analysis . 9
5 Methods of sampling .10
5.1 General .10
5.2 Time-basis sampling .11
5.2.1 Method of taking primary increments .11
5.2.2 Sampling interval .11
5.2.3 Mass of increment .11
5.3 Mass-basis sampling .11
5.3.1 Method of taking primary increments .11
5.3.2 Sampling interval .12
5.3.3 Mass of increment .12
5.4 Stratified random sampling .12
5.4.1 General.12
5.4.2 Time-basis stratified random sampling .13
5.4.3 Mass-basis stratified random sampling .13
5.5 Reference sampling .13
6 Design of mechanical samplers .13
6.1 Safety .13
6.2 Information .13
6.3 Basic requirements .13
6.4 Location of sampling equipment .14
6.5 Provision for checking precision .14
6.6 Provision for testing for bias .14
6.7 General requirements for designing mechanical samplers .14
6.8 Design of falling-stream-type samplers .14
6.8.1 General.14
6.8.2 Cutter velocity .15
6.9 Cross-belt-type primary samplers .17
6.9.1 Operation .17
6.9.2 Design of cross-belt samplers .20
6.10 Maintenance and checking of sampling equipment .21
7 Handling and storage of samples .22
8 Sample preparation .23
9 Bias .23
9.1 Minimization of bias .23
9.2 Checking for precision and bias .24
10 Verification .24
Annex A (normative) Evaluation of sampling equipment for mass-basis sampling .25
Bibliography .30
iv © ISO 2016 – All rights reserved

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
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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
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For an explanation on the meaning of ISO specific terms and expressions related to conformity
assessment, as well as information about ISO’s adherence to the WTO principles in the Technical
Barriers to Trade (TBT), see the following URL: Foreword - Supplementary information
The committee responsible for this document is ISO/TC 27, Solid mineral fuels, Subcommittee SC 4,
Sampling.
This second edition cancels and replaces the first edition (ISO 13909-2:2001), which has been
technically revised.
ISO 13909 consists of the following parts, under the general title Hard coal and coke — Mechanical
sampling:
— Part 1: General introduction
— Part 2: Coal — Sampling from moving streams
— Part 3: Coal — Sampling from stationary lots
— Part 4: Coal — Preparation of test samples
— Part 5: Coke — Sampling from moving streams
— Part 6: Coke — Preparation of test samples
— Part 7: Methods for determining the precision of sampling, sample preparation and testing
— Part 8: Methods of testing for bias
Annex B forms a normative part of this part of ISO 13909. Annex A of this part of ISO 13909 is for
information only.
INTERNATIONAL STANDARD ISO 13909-2:2016(E)
Hard coal and coke — Mechanical sampling —
...