ISO INTERNATIONAL STANDARD 9614-3 First edition 2002-11-01 Acoustics Determination of sound power levels of noise sources using sound intensity - Part 3: Precision method for measurement by scanning Acoustique -Détermination par intensimétrie des niveaux de puissance acoustique émis par les sources de bruit- Partie 3: Methode de precision pour mesurage par balayage Reference number ISO 9614-3:2002(E) ISO @ ISO 2002 HS unde Not for Resal ISO9614-3:2002(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 be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In downloading this file, parties accept therein the responsibility of not infringing Adobe's licensing policy. The Iso Central Secretariat accepts no liability in this area. Adobe is a trademark of 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 ?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 in the country of the requester. ISO copyright office Case postale 56.CH-1211Geneva 20 Tel. + 4122 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 itted without license from IHS Not for Resale ISO 9614-3:2002(E) Contents Page Foreword Introduction .vi 1 Scope 2 Normative references.. 3 Terms and definitions. 4 General requirements .... 4.1 Size of sound source under test. 4.2 Character of sound radiated by the source 4.3 Measurement uncertainty..... 5 Acoustic environment.... 5.1 Criteria for adequacy of the test environment . 5.2 Extraneous intensity.... 5.3 Wind and gas flows.. 5.4 Temperature.... 5.5 Configuration of the surroundings... 5.6 Atmospheric conditions ... 6 Instrumentation 10 6.1 10 6.2 Calibrationand field check. 10 6.3 Time-series of sound intensity and sound pressure.. 10 7 Installation and operation of the source... 10 7.1 10 7.2 Operating conditions of the source under test.... 11 8 Measurement of normal sound intensity component levels .... 8.1 Determination of measurement surface .... 11 8.2 Determination of scanning paths and segments .... 8.3 Measurements ...... 12 8.4 Furtheractions 14 9 Determination of sound power level..... 15 9.1 Calculation of partial sound powers for each partial surface of the measurement surface. 15 9.2 Calculation of normalized sound power level... 15 10 Information to be recorded.. 15 Annex A (informative) List of symbols used in this part of Iso 9614 ... 17 Annex B (normative) Calculation of field indicators.. 19 B.1 General......... 19 B.2 Definition of field indicator 19 B.2.1 Temporal variability indicator, F 19 B.2.2 Unsigned pressure-intensity indicator, F pln B.2.3 Signed pressure-intensity indicator, F pln 20 B.2.4 Field non-uniformity indicator, Fs. .21 Annex C (normative) Procedure for achieving the desired accuracy 22 C.1 Qualification requirements. 22 C.1.1 General. 22 ili by IHS under Not for Resale ISO 9614-3:2002(E) C.1.2 Check for the adequacy of the averaging time .... C.1.3 Check for the repeatability of the scan on a partial surface .22 C.1.4 Check for the adequacy of the measurement equipment ... 2 C.1.5 Check for the presence of strong extraneous noise. .23 C.1.6 Check for the field non-uniformity..... C.2 Action to be taken to increase the grade of accuracy of determination . 23 Annex D (informative) Effects of airflow on measurement of sound intensity.. ..26 Annex E (informative) Effect of sound absorption within the measurement surface. .. 27 Annex F (informative) Measurement surface and scanning