1、WB11885_BSI_StandardCovs_2013_AW.indd 1 15/05/2013 15:06Gas analysis Comparison methods for the determination of the composition of gas mixtures based on one- and two-point calibrationBS ISO 12963:2017 Incorporating corrigendum May 2017National forewordThis British Standard is the UK implementation
2、of ISO 12963:2017.The UK participation in its preparation was entrusted to Technical Committee PTI/15, Natural Gas and Gas Analysis.A list of organizations represented on this committee can be obtained on request to its secretary.This publication does not purport to include all the necessary provisi
3、ons of a contract. Users are responsible for its correct application. The British Standards Institution 2017 Published by BSI Standards Limited 2017ISBN 978 0 580 85350 0ICS 71.040.40Compliance with a British Standard cannot confer immunity from legal obligations.This British Standard was published
4、under the authority of the Standards Policy and Strategy Committee on 31 May 2017.Amendments/corrigenda issued since publicationDate Text affected 31 May 2017 Images insertedBRITISH STANDARDBS ISO 12963:2017 ISO 2017Gas analysis Comparison methods for the determination of the composition of gas mixt
5、ures based on one- and two-point calibrationAnalyse des gaz Mthodes de comparaison pour la dtermination de la composition des mlanges de gaz bases sur un ou deux points dtalonnageINTERNATIONAL STANDARDISO12963First edition2017-04-15Reference numberISO 12963:2017(E)BS ISO 12963:2017ISO 12963:2017(E)i
6、i ISO 2017 All rights reservedCOPYRIGHT PROTECTED DOCUMENT ISO 2017, Published in SwitzerlandAll rights reserved. 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
7、on the internet or an intranet, without prior written permission. Permission can be requested from either ISO 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
8、 09 47copyrightiso.orgwww.iso.orgBS ISO 12963:2017ISO 12963:2017(E)Foreword ivIntroduction v1 Scope . 12 Normative references 13 Terms and definitions . 14 Symbols 25 Abbreviated terms 26 Principle 36.1 General requirements . 36.2 Calibration methods . 47 Main procedure 47.1 Pre-requisites . 47.2 Se
9、quence of operations (overview) 47.3 Calibration and measurement designs . 57.3.1 General 57.3.2 Single-point exact-match calibration (SPEM) . 67.3.3 Single-point through origin calibration (SPO) . 67.3.4 Two-point calibration with a blank (TPB) . 77.3.5 Two-point calibration with bracketing (TPC) 7
10、7.3.6 Multipoint calibration (MPC) 88 Performance evaluation of the measuring system 88.1 General . 88.2 Sources of performance evaluation data and alternative approach 118.2.1 Performance evaluation other than in-house 118.2.2 Alternative for performance evaluation .119 Quality assurance measures .
11、119.1 Validation of the assumptions made . 119.2 Drift/stability control of the measuring system .1110 Report of results 1210.1 Calibration gas certificates 1210.2 Report of analysis 12Annex A (normative) System-stability check required when using exact-match and bracketing designs .13Annex B (norma
12、tive) Statistics and sensitivity coefficients used in Clause 7 .15Annex C (normative) Alternative approach to assessing the nonlinearity contribution 17Annex D (informative) Worked-out example 19Annex E (informative) Using the designs without preceding system performance evaluation .22Bibliography .
13、24 ISO 2017 All rights reserved iiiContents PageBS ISO 12963:2017ISO 12963:2017(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 normally carried out through
14、 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 collaborate
15、s 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 crit
16、eria 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
17、 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
18、used in this document is information given for the convenience of users and does not constitute an endorsement.For an explanation on the voluntary nature of standards, the meaning of ISO specific terms and expressions related to conformity assessment, as well as information about ISOs adherence to t
19、he World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see the following URL: www.iso.org/iso/foreword.html.This document was prepared by Technical Committee ISO/TC 158, Analysis of gases.iv ISO 2017 All rights reservedBS ISO 12963:2017ISO 12963:2017(E)IntroductionWher
20、eas the comparison methods described in ISO 6143 based on multipoint calibration are in principle suited for all applications in gas analysis for determining the composition of calibration gas mixtures, in many cases, simpler calibration methods can be used. These methods typically require a smaller
21、 number of calibration gas mixtures with a traceable composition.One- and two-point calibration of instruments is widely used in the gas industry and in national metrology institutes. They often constitute fair compromise between costs and efforts on one hand, and accuracy on the other. These simple
22、r methods require validation to confirm that the conditions of use are appropriate.It is the intention of this document to set up and describe comparison methods and data evaluation techniques based on one- and two-point calibration. The applicable conditions and limitations of the methods are deriv
23、ed from the analytical requirements and are clearly specified.This document describes the assessment, calculation and expression of measurement uncertainty arising from significant contributors in the different comparison methods. ISO 2017 All rights reserved vBS ISO 12963:2017This page deliberately
24、 left blankGas analysis Comparison methods for the determination of the composition of gas mixtures based on one- and two-point calibration1 ScopeThis document provides methods for calibrating an instrument with one or two calibration gas mixtures, determining the composition of a gas sample, and ev
25、aluating the uncertainty of the composition of the gas sample in relation to the uncertainty of the composition of the calibration gases used and the contribution of the measurement process.This document sets requirements to, and acceptance criteria for, the utilization of different measurement cali
26、bration designs with a limited (i.e. minimum) number of calibration gas mixtures used in calibration.The methods in this document are described for amount-of-substance fractions, but are also applicable for other composition quantities (such as mass fractions, volume fractions or concentrations).2 N
27、ormative referencesThe 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
28、 amendments) applies.ISO 6141, Gas analysis Contents of certificates for calibration gas mixturesISO 6143, Gas analysis Comparison methods for determining and checking the composition of calibration gas mixturesISO 7504, Gas analysis VocabularyISO/IEC Guide 98-3:2008, Uncertainty of measurement Part
29、 3: Guide to the expression of uncertainty in measurement (GUM:1995)ISO/IEC Guide 99, International vocabulary of metrology Basic and general concepts and associated terms (VIM)3 Terms and definitionsFor the purposes of this document, the terms and definitions given in ISO 7504, ISO/IEC Guide 983 an
30、d ISO/IEC Guide 99 apply.ISO and IEC maintain terminological databases for use in standardization at the following addresses: IEC Electropedia: available at http:/www.electropedia.org/ ISO Online browsing platform: available at http:/www.iso.org/obpINTERNATIONAL STANDARD ISO 12963:2017(E) ISO 2017 A
31、ll rights reserved 1BS ISO 12963:2017ISO 12963:2017(E)4 Symbolsjcoefficients of the best available calibration function f ( j = 0, 1, , N) with N 3 as determined in the performance evaluation procedure, with N being the order of the polynomialbjparameters of the simplified analysis function g ( j =
32、0, 1)jparameters of the best-available analysis function g ( j = 0, 1, ., N) with N 3 as determined in the performance evaluation procedure, with N being the order of the polynomialf calibration function, y = f(x)g analysis function, x = g(y)k coverage factorm number of replicate measurements takenN
33、 order of the polynomialR range of amount-of-substance fractions within which the selected method of calibration is applied to samples of unknown composition (hereinafter: unknown samples)U(q) expanded uncertainty associated with the quantity, q, U(q) = k u(q)u(q) standard uncertainty associated wit
34、h the quantity, qu() uncertainty contribution due to zero-deviations and analyser nonlinearityu2(q) variance associated with the quantity, qx amount fraction(xi, yi) calibration point(s) (i = 1, 2, ., n), with n being its numbery(l)instrumental response, with l indicating the replicate numbery mean
35、replicated instrumental responses goodness of fit; a measure of local compatibility of a calibration point with the calculated calibration or analysis function bias due to zero-deviation and analyser nonlinearity bias average bias5 Abbreviated termsb blankGLS generalized least squaresMPC multipoint
36、calibration2 ISO 2017 All rights reservedBS ISO 12963:2017ISO 12963:2017(E)Re measurement of the matching referencer subscript denoting a calibration gas mixturer1, r2 calibration gas mixtures bracketing the composition of the unknown sampleS unknown gas samples subscript denoting an unknown gas sam
37、pleSSD sum of weighted squared deviationsSPEM single-point exact-match calibrationSPO single-point through origin calibrationTPB two-point calibration using a single point and a blankTPC two-point calibration6 Principle6.1 General requirementsThe composition of a gas mixture is determined by separat
38、e measurement of the amount fraction of every specified component. “Separate” implies that the response obtained for the component of interest is treated independently of any other response obtained for any other component. It does not impede obtaining several responses for several components in the
39、 same instrument run. Therefore, the procedure for determining the amount fraction of only one specified component is described. Possible interferences of other components on the measurement of the component of interest shall be avoided or corrected for separately. This subject is not further addres
40、sed in this document.The procedure for determining the amount fraction x of a specified component X in a sample of a gas mixture, or in a series of such samples, is performed in a sequence of steps as summarized below.a) Specify the analytical range of interest, R, i.e. the range of the amount fract
41、ion x to be determined, and the acceptable or required (if applicable) uncertainty level.b) Specify the analytical method and the measuring system to be used:1) calibration range (to encompass the analytical range);2) composition, including uncertainty, of the calibration gas mixtures;3) parameters
42、of the analytical method;4) measuring conditions;5) number and sequence of calibration measurements (see 8.1).c) Select, from the list given in 6.2, an approach for calibration and determining the amount fractions of components in unknown samples in the regular, i.e. daily mode when one- and two-poi
43、nt based analysis functions are used.d) For the relevant ranges of responses and component amount fractions, determine the uncertainty level of the prospective results based on the analysis function. If the result is acceptable, performance evaluation was successful.For the calculation of the measur
44、ement uncertainty of results obtained in the regular calibration mode, an estimate u() for the contribution of possible nonlinearity of the system is needed. This estimate is calculated in a performance evaluation of the system according to Clause 8 and Annex C. ISO 2017 All rights reserved 3BS ISO
45、12963:2017ISO 12963:2017(E)The evaluation is best done after the specifications according to a) to c) are set. The estimate is used in all subsequent regular calibrations until there is reason to assume significant changes in the instrument performance. The main reasons for such changes are given in
46、 9.1.e) Perform calibration and measurement according to the steps given in Clause 7.6.2 Calibration methodsThe following calibration methods for determining the amount fraction of a specified component in an unknown gas sample may apply:a) single-point exact-match calibration (SPEM) and direct tran
47、sfer of value and uncertainty of the matching calibration gas mixture;b) single-point through origin calibration (SPO) and transfer of the value assuming a straight-line calibration function through the origin;c) two-point calibration using a single-point and a blank (TPB) calculation of the value f
48、rom a straight-line analysis function;d) two-point calibration: bracketing using two calibration gas mixtures (TPC).NOTE Multipoint calibration (MPC) uses at least three calibration points.7 Main procedure7.1 Pre-requisitesStability of the system within the period of time equal to a normal calibrati
49、on interval shall be demonstrated during method validation. The use of unstable systems is strongly discouraged in general, in particular for designs SPO and TPB in 6.2. For use of designs SPEM and TPC with not sufficiently stable systems, see Annex A.7.2 Sequence of operations (overview)Figure 1 illustrates the basic steps of carrying out measurements according to the calibration methods described in this document. Aims, steps and frequency of the performance evaluation are described in Clause 8.4 ISO 2017 A
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