ISO INTERNATIONAL STANDARD 14956 First edition 2002-08-15 Air quality Evaluation of the suitability of a measurement procedure by comparison with a required measurement uncertainty Qualite de I'air- Evaluation de I'aptitude a I'emploi d'une procedure de mesurage par comparaison avec une incertitude de mesure requise Reference number ISO 14956:2002(E) @ ISO 2002 ISO14956:2002(E) PDF disclaimer This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but shall not area. Adobe is atrademarkof Adobe Systems Incorporated. Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation parameters were optimized for printing. Every care has been taken to ensure that the file is suitable for use by IsO member bodies. In the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below. ? ISO2002 All rights 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 IsO's member body in the country of the requester. ISO copyright office Case postale 56 . CH-1211 Geneva 20 Tel. + 41 22 749 01 11 Fax + 41 22 749 09 47 E-mail [email protected] Web www.iso.ch Printed in Switzerland @ ISO 2002 - All rights reserved ISO14956:2002(E) Contents Page Foreword. Introduction 1 2 Normativereference 3 Termsanddefinitions 4 Symbols and abbreviated terms 5 Principle 6 Requirements 6.1 Methodsandmaterials 6.2 Performancecharacteristics 6.3 Required measurement quality.. Required performance related to dynamic conditions.. 7.1 General 7.2 Response time. 8 Requiredperformancerelatedtostationaryconditions 8.1 Analytical function, model function and variance function. 8.2 Identification of sources of uncertainty .... 9 8.3 Assignmentofsourcesofuncertaintytoperformancecharacteristics 8.4 Definition and quantification of conditions of operation of the measurement system. 10 8.5 Quantificationoftheimpactofselectedperformancecharacteristicsaspartialstandard uncertainties.. 8.6 Estimation of the combined standard uncertainty .. 14 8.7 Estimation of the expanded uncertainty.. 14 8.8 Evaluation of compliance with the required measurement quality 14 9 Field verification. .14 10 Report. 15 Annex A (informative) Default ranges of chemical interferents.. 16 Annex B (normative) Coverage factors derived from effective degrees of freedom. 18 Annex C (informative) Example of an assessment of compliance of Uv fluorescence method for SO2 with requirements on ambient air quality 19 Annex D (informative) Examples of field verification programme: 24 Bibliography. 26 eserved ili