1、BS ISO 13909-2:2016Hard coal and coke Mechanical samplingPart 2: Coal Sampling from movingstreamsBSI Standards PublicationWB11885_BSI_StandardCovs_2013_AW.indd 1 15/05/2013 15:06BS ISO 13909-2:2016 BRITISH STANDARDNational forewordThis British Standard is the UK implementation of ISO 13909-2:2016.It
2、 supersedes BS ISO 13909-2:2001 which is withdrawn.The UK participation in its preparation was entrusted to TechnicalCommittee PTI/16, Solid mineral fuels.A list of organizations represented on this committee can beobtained on request to its secretary.This publication does not purport to include all
3、 the necessaryprovisions of a contract. Users are responsible for its correctapplication. The British Standards Institution 2016.Published by BSI Standards Limited 2016ISBN 978 0 580 83175 1ICS 73.040Compliance with a British Standard cannot confer immunity fromlegal obligations.This British Standar
4、d was published under the authority of theStandards Policy and Strategy Committee on 30 June 2016.Amendments/corrigenda issued since publicationDate T e x t a f f e c t e dBS ISO 13909-2:2016 ISO 2016Hard coal and coke Mechanical sampling Part 2: Coal Sampling from moving streamsHouille et coke chan
5、tillonnage mcanique Partie 2: Charbon chantillonnage en continuINTERNATIONAL STANDARDISO13909-2Second edition2016-07-01Reference numberISO 13909-2:2016(E)BS ISO 13909-2:2016ISO 13909-2:2016(E)ii ISO 2016 All rights reservedCOPYRIGHT PROTECTED DOCUMENT ISO 2016, Published in SwitzerlandAll rights res
6、erved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior written permission. Permission can be requested from either I
7、SO at the address below or ISOs member body in the country of the requester.ISO copyright officeCh. de Blandonnet 8 CP 401CH-1214 Vernier, Geneva, SwitzerlandTel. +41 22 749 01 11Fax +41 22 749 09 47copyrightiso.orgwww.iso.orgBS ISO 13909-2:2016ISO 13909-2:2016(E)Foreword v1 Scope . 12 Normative ref
8、erences 13 Terms and definitions . 14 Establishing a sampling scheme 14.1 General . 14.2 Design of the sampling scheme 24.2.1 Material to be sampled . 24.2.2 Division of lots . 24.2.3 Basis of sampling . 24.2.4 Precision of sampling . 24.2.5 Bias of sampling 34.3 Precision of results 34.3.1 Precisio
9、n and total variance . 34.3.2 Primary increment variance 44.3.3 Preparation and testing variance 44.3.4 Number of sub-lots and number of increments per sub-lot 44.4 Minimum mass of sample 74.5 Mass of primary increment 94.6 Size analysis . 95 Methods of sampling .105.1 General 105.2 Time-basis sampl
10、ing . 115.2.1 Method of taking primary increments .115.2.2 Sampling interval .115.2.3 Mass of increment 115.3 Mass-basis sampling . 115.3.1 Method of taking primary increments .115.3.2 Sampling interval .125.3.3 Mass of increment 125.4 Stratified random sampling 125.4.1 General. 125.4.2 Time-basis s
11、tratified random sampling 135.4.3 Mass-basis stratified random sampling 135.5 Reference sampling 136 Design of mechanical samplers 136.1 Safety 136.2 Information . 136.3 Basic requirements 136.4 Location of sampling equipment 146.5 Provision for checking precision 146.6 Provision for testing for bia
12、s 146.7 General requirements for designing mechanical samplers .146.8 Design of falling-stream-type samplers . 146.8.1 General. 146.8.2 Cutter velocity .156.9 Cross-belt-type primary samplers 176.9.1 Operation . 176.9.2 Design of cross-belt samplers 206.10 Maintenance and checking of sampling equipm
13、ent 217 Handling and storage of samples .228 Sample preparation 23 ISO 2016 All rights reserved iiiContents PageBS ISO 13909-2:2016ISO 13909-2:2016(E)9 Bias 239.1 Minimization of bias 239.2 Checking for precision and bias 2410 Verification 24Annex A (normative) Evaluation of sampling equipment for m
14、ass-basis sampling 25Bibliography .30iv ISO 2016 All rights reservedBS ISO 13909-2:2016ISO 13909-2:2016(E)ForewordISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is norm
15、ally 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 t
16、he 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
17、 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 docume
18、nt 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/
19、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 on the meaning of ISO specific terms and expressions related to conformity assessment, as well as information about ISOs adherence to the WTO prin
20、ciples in the Technical Barriers to Trade (TBT), see the following URL: Foreword - Supplementary informationThe 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
21、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: C
22、oke 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 biasAnnex B forms a normative part of this part of ISO 13909. Annex A of this part of ISO 13909 is for in
23、formation only. ISO 2016 All rights reserved vBS ISO 13909-2:2016BS ISO 13909-2:2016Hard coal and coke Mechanical sampling Part 2: Coal Sampling from moving streams1 ScopeThis part of ISO 13909 specifies procedures and requirements for the design and establishment of mechanical samplers for the samp
24、ling of coal from moving streams and describes the methods of sampling used.It does not cover mechanical sampling from stationary lots which is dealt with in ISO 13909-31.2 Normative referencesThe following documents, in whole or in part, are normatively referenced in this document and are indispens
25、able for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.ISO 13909-1:2016, Hard coal and coke Mechanical sampling Part 1: General introductionISO 13909-4, Hard coal and cok
26、e Mechanical sampling Part 4: Coal Preparation of test samplesISO 13909-7, Hard coal and coke Mechanical sampling Part 7: Methods for determining the precision of sampling, sample preparation and testingISO 13909-8, Hard coal and coke Mechanical sampling Part 8: Methods of testing for biasISO 21398,
27、 Hard coal and coke Guidance to the inspection of mechanical sampling systems3 Terms and definitionsFor the purposes of this document, the terms and definitions given in ISO 13909-1 apply.4 Establishing a sampling scheme4.1 GeneralThe general procedure for establishing a sampling scheme is as follow
28、s.a) Define the quality parameters to be determined and the types of samples required.b) Define the lot.c) Define or assume the precision required (see 4.3.1).d) Determine the method of combining the increments into samples and the method of sample preparation (see ISO 13909-4).e) Determine or assum
29、e the variability of the coal (see 4.3.2) and the variance of preparation and testing (see 4.3.3). Methods for determining variability and the variance of preparation and testing are given in ISO 13909-7.INTERNATIONAL STANDARD ISO 13909-2:2016(E) ISO 2016 All rights reserved 1BS ISO 13909-2:2016ISO
30、13909-2:2016(E)f) Establish the number of sub-lots and the number of increments per sub-lot required to attain the desired precision (see 4.3.4).g) Decide whether to use time-basis or mass-basis sampling (see Clause 5) and define the sampling intervals in minutes for time-basis sampling or in tonnes
31、 for mass-basis sampling.h) Ascertain the nominal top size of coal for the purpose of determining the minimum mass of sample (see 4.4 and Table 1).NOTE The nominal top size may initially be ascertained by consulting the consignment details, or by visual estimation, and may be verified, if necessary,
32、 by preliminary test work.i) Determine the minimum average increment mass (see 4.5).4.2 Design of the sampling scheme4.2.1 Material to be sampledThe first stage in the design of the scheme is to identify the coal to be sampled. Samples may be required for technical evaluation, process control, quali
33、ty control and for commercial reasons by both the producer and the customer. It is essential to ascertain exactly at what stage in the coal-handling process the sample is required and, as far as practicable, to design the scheme accordingly. In some instances, however, it may prove impracticable to
34、obtain samples at the preferred points and, in such cases, a more practicable alternative is required.4.2.2 Division of lotsA lot may be sampled as a whole or as a series of sub-lots, e.g. coal dispatched or delivered over a period of time, a ship load, a train load, a wagon load or coal produced in
35、 a certain period, e.g. a shift.It may be necessary to divide a lot into a number of sub-lots in order to improve the precision of the results. For lots sampled over long periods, it may be expedient to divide the lot into a series of sub-lots, obtaining a sample for each.4.2.3 Basis of samplingSamp
36、ling may be carried out on either a time-basis or a mass-basis. In time-basis sampling, the sampling interval is defined in minutes and seconds and the increment mass is proportional to the flow rate at the time of taking the increment. In mass-basis sampling, the sampling interval is defined in ton
37、nes and the mass of increments constituting the sample is uniform. Of these two alternatives, time-basis sampling is easier to implement and verify, because only a fixed speed cutter and a timing device are required. On the other hand, for mass-basis sampling, a conveyor belt weightometer is require
38、d as well as a device that is controlled sufficiently to adjust the primary cutter speed increment by increment to achieve uniform increment mass.4.2.4 Precision of samplingAfter the desired sampling precision has been selected, the number of sub-lots and the minimum number of increments per sub-lot
39、 collected shall be determined as described in 4.3.4, and the average mass of the primary increments shall be determined as described in 4.5.For single lots, the quality variation shall be assumed as the worst case (see 4.3.2). The precision of sampling achieved may be measured using the procedure o
40、f replicate sampling (see ISO 13909-7).At the start of regular sampling of unknown coals, the worst-case quality variation shall be assumed, in accordance with 4.3.2. When sampling is in operation, a check may be carried out to confirm that the desired precision has been achieved, using the procedur
41、es described in ISO 13909-7.2 ISO 2016 All rights reservedBS ISO 13909-2:2016ISO 13909-2:2016(E)If any subsequent change in precision is required, the number of sub-lots and of increments shall be changed as determined in 4.3.4 and the precision attained shall be rechecked. The precision shall also
42、be checked if there is any reason to suppose that the variability of the coal being sampled has increased. The number of increments determined in 4.3.4 applies to the precision of the result when the sampling errors are large relative to the testing errors, e.g. for moisture content.4.2.5 Bias of sa
43、mplingIt is of particular importance in sampling to ensure, as far as possible, that the parameter to be measured is not altered by the sampling and sample preparation process or by subsequent storage prior to testing. This may require, in some circumstances, a limit on the minimum mass of primary i
44、ncrement (see 4.5).When collecting samples for moisture determination from lots over an extended period, it may be necessary to limit the standing time of samples by dividing the lot into a number of sub-lots (see 4.3.4).Sampling systems shall be tested for bias in accordance with the methods given
45、in ISO 13909-8.4.3 Precision of results4.3.1 Precision and total varianceIn all methods of sampling, sample preparation and analysis, errors are incurred and the experimental results obtained from such methods for any given parameter will deviate from the true value of that parameter. While the abso
46、lute deviation of a single result from the “true” value cannot be determined, it is possible to make an estimate of the precision of the experimental results. This is the closeness with which the results of a series of measurements made on the same coal agree among themselves, and the deviation of t
47、he mean of the results from an accepted reference value, i.e. the bias of the results (see ISO 13909-8).It is possible to design a sampling scheme by which, in principle, an arbitrary level of precision can be achieved.The desired overall precision for a lot is normally agreed between the parties co
48、ncerned. In the absence of such agreement, a value of one tenth of the ash content may be assumed up to 10 % ash, subject to a maximum of 1 % absolute for ash contents above 10 %.The theory of the estimation of precision is discussed in ISO 13909-7. The following formula is derived:PVnVmLIPT=+2 (1)w
49、herePLis the estimated index of overall precision of sampling, sample preparation and testing for the lot, expressed as a percentage absolute;VIis the primary increment variance;n is the number of increments per sub-lot;m is the number of sub-lots in the lot;VPTis the preparation and testing variance.If the quality of a coal of a type not previously sampled is required, then in order to devise a sampling scheme, assumptions have to be made about the variability (see 4.3.2). The precision actually achi
