1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationBS ISO 11352:2012Water quality Estimationof measurement uncertaintybased on validation and qualitycontrol dataBS ISO 11352:2012 BRITISH STANDARDNational forewordThis British Stan
2、dard is the UK implementation of ISO 11352:2012.The UK participation in its preparation was entrusted to TechnicalCommittee EH/3/2, Physical chemical and biochemical methods.A list of organizations represented on this committee can beobtained on request to its secretary.This publication does not pur
3、port to include all the necessaryprovisions of a contract. Users are responsible for its correctapplication. The British Standards Institution 2012. Published by BSI StandardsLimited 2012ISBN 978 0 580 61295 4ICS 13.060.45Compliance with a British Standard cannot confer immunity fromlegal obligation
4、s.This British Standard was published under the authority of theStandards Policy and Strategy Committee on 31 July 2012.Amendments issued since publicationDate Text affectedBS ISO 11352:2012 ISO 2012Water quality Estimation of measurement uncertainty based on validation and quality control dataQuali
5、t de leau Estimation de lincertitude de mesure base sur des donnes de validation et de contrle qualitINTERNATIONAL STANDARDISO11352First edition2012-07-01Reference numberISO 11352:2012(E)BS ISO 11352:2012ISO 11352:2012(E)ii ISO 2012 All rights reservedCOPYRIGHT PROTECTED DOCUMENT ISO 2012All rights
6、reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or ISOs member body in the country of the re
7、quester.ISO copyright officeCase postale 56 CH-1211 Geneva 20Tel. + 41 22 749 01 11Fax + 41 22 749 09 47E-mail copyrightiso.orgWeb www.iso.orgPublished in SwitzerlandBS ISO 11352:2012ISO 11352:2012(E) ISO 2012 All rights reserved iiiContents PageForeword ivIntroduction v1 Scope 12 Normative referenc
8、es . 13 Terms and definitions . 14 Symbols . 45 Principle . 56 Procedure 57 Preparative considerations for the estimation of measurement uncertainty . 67.1 Specification of the measurement 67.2 Specification of the parametric form in which the measurement uncertainty is reported 68 Evaluation of ava
9、ilable precision and bias data . 78.1 Approach and criteria . 78.2 Within-laboratory reproducibility 88.3 Method and laboratory bias 109 Calculation of the combined standard uncertainty 1410 Calculation of the expanded uncertainty 1511 Estimation of measurement uncertainty from reproducibility stand
10、ard deviation .1512 Report .15Annex A (normative) Estimation of the standard uncertainty from range control charts 16Annex B (informative) Examples of the estimation of measurement uncertainty 17Bibliography .26BS ISO 11352:2012ISO 11352:2012(E)ForewordISO (the International Organization for Standar
11、dization) 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
12、 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.International Stand
13、ards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an Inter
14、national Standard requires approval by at least 75 % of the member bodies casting a vote.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.ISO 11352 was
15、 prepared by Technical Committee ISO/TC 147, Water quality, Subcommittee SC 2, Physical, chemical and biochemical methods.iv ISO 2012 All rights reservedBS ISO 11352:2012ISO 11352:2012(E)IntroductionThe basic principles of the estimation of measurement uncertainty are set out in ISO/IEC Guide 98-3.
16、There are several ways of estimating measurement uncertainty depending on the purpose of the estimation and the available data; Eurolab TR 19gives an overview of the main approaches.This International Standard specifies a set of procedures to enable laboratories to estimate the measurement uncertain
17、ty of their results, using an approach based on quality control results and validation data. It is structured in a way that is applicable to analysts that do not have a thorough understanding of metrology or statistics.NEN 77798and Nordtest TR 53710have been used as a basis for developing this Inter
18、national Standard. The approach taken is “top-down”, contrary to the mainly “bottom-up” strategy adopted in ISO/IEC Guide 98-3.It is statistically acceptable to combine a precision estimate and the uncertainty associated with the bias into one uncertainty measure. The sources of data for this approa
19、ch are method validation and analytical quality control. The experimental approach specified in this International Standard enables a greater coverage of the sources of variation observed during routine use of the analytical method. ISO 2012 All rights reserved vBS ISO 11352:2012BS ISO 11352:2012Wat
20、er quality Estimation of measurement uncertainty based on validation and quality control data1 ScopeThis International Standard specifies methods for the estimation of measurement uncertainty of chemical and physicochemical methods in single laboratories based on validation data and analytical quali
21、ty control results obtained within the field of water analysis.NOTE 1 The principles of the estimation of uncertainty specified in this International Standard are consistent with the principles described in ISO/IEC Guide 98-3.In this International Standard, the quantification of measurement uncertai
22、nty relies on performance characteristics of a measurement procedure obtained from validation and the results of internal and external quality control.NOTE 2 The approaches specified in this International Standard are mainly based on QUAM11, NEN 77798, Nordtest TR 53710, and Eurolab TR 19.NOTE 3 Thi
23、s International Standard only addresses the evaluation of measurement uncertainty for results obtained from quantitative measurement procedures. The uncertainties associated with results obtained from qualitative procedures are not considered.2 Normative referencesThe following referenced documents
24、are indispensable for the application 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/IEC Guide 98-3:2008, Uncertainty of measurement Part 3: Guide to the expression o
25、f uncertainty in measurement (GUM:1995)3 Terms and definitionsFor the purposes of this document, the following terms and definitions apply.NOTE 1 The terms and definitions listed are generally reproduced without the Notes which are associated with the terms and definitions in the respective referenc
26、es.NOTE 2 The terms concerning precision data from interlaboratory trials are taken from ISO 3534-2:20061because the definitions in ISO/IEC Guide 99:20077are wider than those in ISO 3534-2:2006 as they include different measurement procedures, which is not appropriate for this International Standard
27、.3.1truenesscloseness of agreement between the average of an infinite number of replicate measured quantity values and a reference quantity valueISO/IEC Guide 99:20077, 2.143.2precisioncloseness of agreement between indications or measured quantity values obtained by replicate measurements on the sa
28、me or similar objects under specified conditionsISO/IEC Guide 99:20077,2.15INTERNATIONAL STANDARD ISO 11352:2012(E) ISO 2012 All rights reserved 1BS ISO 11352:2012ISO 11352:2012(E)3.3errormeasurement errormeasured quantity value minus a reference quantity valueISO/IEC Guide 99:20077, 2.163.4systemat
29、ic errorsystematic measurement errorcomponent of measurement error that in replicate measurements remains constant or varies in a predictable mannerISO/IEC Guide 99:20077, 2.173.5biasmeasurement biasestimate of a systematic measurement errorISO/IEC Guide 99:20077, 2.183.6random errorrandom measureme
30、nt errorcomponent of measurement error that in replicate measurements varies in an unpredictable mannerISO/IEC Guide 99:20077, 2.193.7repeatability conditionsobservation conditions where independent test/measurement results are obtained with the same method on identical test/measurement items in the
31、 same test or measuring facility by the same operator using the same equipment within short intervals of timeISO 3534-2:20061, 3.3.63.8repeatabilityprecision under repeatability conditionsISO 3534-2:20061, 3.3.53.9batchseries of measurements made under repeatability conditions3.10intermediate precis
32、ion conditionsconditions where test results or measurement results are obtained with the same method, on identical test/measurement items in the same test or measurement facility, under some different operating conditionNOTE There are four elements to the operating condition: time, calibration, oper
33、ator and equipment.ISO 3534-2:20061, 3.3.163.11intermediate precisionprecision under intermediate precision conditionsISO 3534-2:20061, 3.3.152 ISO 2012 All rights reservedBS ISO 11352:2012ISO 11352:2012(E)3.12within-laboratory reproducibilityintermediate measurement precision where variations withi
34、n one laboratory alone are included3.13reproducibility conditionsobservation conditions where independent test/measurement results are obtained with the same method on identical test/measurement items in different test or measurement facilities with different operators using different equipmentISO 3
35、534-2:20061, 3.3.113.14reproducibilityprecision under reproducibility conditionsISO 3534-2:20061, 3.3.103.15uncertaintymeasurement uncertaintynon-negative parameter characterizing the dispersion of the quantity values being attributed to a measurand, based on the information usedISO/IEC Guide 99:200
36、77, 2.263.16standard uncertaintystandard measurement uncertaintymeasurement uncertainty expressed as a standard deviationISO/IEC Guide 99:20077, 2.303.17combined standard uncertaintycombined standard measurement uncertaintystandard measurement uncertainty that is obtained using the individual standa
37、rd measurement uncertainties associated with the input quantities in a measurement modelISO/IEC Guide 99:20077, 2.313.18relative standard measurement uncertaintystandard measurement uncertainty divided by the absolute value of the measured quantity valueISO/IEC Guide 99:20077, 2.323.19target measure
38、ment uncertaintymeasurement uncertainty specified as an upper limit and decided on the basis of the intended use of measurement resultsISO/IEC Guide 99:20077, 2.343.20expanded uncertaintyexpanded measurement uncertaintyproduct of a combined standard measurement uncertainty and a factor larger than t
39、he number oneNOTE The term “factor” in this definition refers to a coverage factor.ISO/IEC Guide 99:20077, 2.35 ISO 2012 All rights reserved 3BS ISO 11352:2012ISO 11352:2012(E)3.21coverage factornumber larger than one by which a combined standard measurement uncertainty is multiplied to obtain an ex
40、panded measurement uncertaintyISO/IEC Guide 99:20077, 2.384 Symbolsb bias estimated as the difference between mean measured value and an accepted reference valuebibias of the ith reference material respectively deviation from the complete recovery (100 %) of the ith recovery experimentbrmsroot mean
41、square of individual bias values respectively of the deviations from recovery experimentsDidifference between the measurement result and the assigned value of the ith sample of the interlaboratory comparisonDrmsroot mean square of the differencesd2 factor for the calculation of the standard deviatio
42、n from the mean range Ri variable related to an observation of a seriesj variable related to a source of uncertaintyJ total number of sources of uncertaintyk coverage factornilcnumber of analysed interlaboratory comparison samplesnMnumber of measurementsnp,inumber of participating laboratories for s
43、ample inrnumber of reference materialsnnumber of recovery experimentsRmean ranges standard deviationsbstandard deviation of the measured values of the reference materialsR,ireproducibility standard deviation from the interlaboratory comparison for sample isRwstandard deviation of the quality control
44、 resultsU expanded uncertaintyUrelrelative expanded uncertaintyuccombined standard uncertaintyuc,relcombined relative standard uncertaintyujstandard uncertainties from different sources j4 ISO 2012 All rights reservedBS ISO 11352:2012ISO 11352:2012(E)uj,relrelative standard uncertainties from differ
45、ent sources juaddstandard uncertainty in the concentration of the analyte addedubstandard uncertainty component associated with method and laboratory biasuconcstandard uncertainty of the concentration of the addition solutionuCrefmean standard uncertainty of the reference values or mean standard unc
46、ertainty of the assigned values of the interlaboratory comparison samplesuCrefstandard uncertainty of the reference value uCiref,standard uncertainty of the assigned value of the interlaboratory sample iuRwstandard uncertainty component for the within-laboratory reproducibilityur,rangestandard uncer
47、tainty component from the range control chart (obtained under repeatability conditions)uRwbat,standard uncertainty component resulting from variations between batchesuRwstand,standard uncertainty component of the results from the standard solution which is used as quality control sampleuVstandard un
48、certainty component of the volume addeduV,bsystematic standard uncertainty component of the volume addeduV,reprandom standard uncertainty component of the volume added (obtained under repeatability conditions)eV,maxmaximum deviation of the volume from the specified value (producer information) recov
49、ery5 PrincipleA measurement result of a laboratory is an estimate of the value of the measurand. The quality of this estimate depends on the inevitable uncertainty that is inherent to the measurement result. In principle, the measurement uncertainty is a property of individual measurement results. The estimation of the measurement uncertainty for each individual measurement result is usually not necessary, if the measurement result originates from
