ISO INTERNATIONAL STANDARD 9614-2 First edition 1996-08-01 Acoustics s -- Determination of sound power levels of noise sources using sound intensity Part 2: Measurement by scanning Acoustique -Determinationpar intensimetriedes niveaux depuissance acoustique émis par les sources de bruit- Partie 2:Mesurage parbalayage This material is reproduced fron Iso documents under International Organization for Standardization (Iso) Copyright License number IHS/IcC/1996. Not for resale. No part of these Iso documents may be reproduced in anyform, electronic retrieval system or otherwise, except as aliowed in the copyright law of the country of use, or with the prior written consent of Iso (Case postale 56, 1211 Geneva 20, Switzerland, Fax +41 22 7341079),IHS ortheisoLicensor'smembers. TSO Reference number ISO 9614-2:1996(E) ISO 9614-2:1996(E) Foreword Iso (the International Organization for Standardization) is a worldwide of preparing International Standards is normally carried out through IsO which a technical committee has been established has the right to be 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. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International a vote. International Standard ISO 9614-2 was prepared by Technical Committee ISO/TC 43, Acoustics, Subcommittee SC 1, Noise. ISO 9614 s of the following parts, consists s,underthe title general Acoustics - Determination of sound power levels of noise sources using sound intensity. -Part1:Measurementat discretepoints - Part 2: Measurement by scanning -- Part 3: Precision method for measurement by scanning Annexes A and B form an integral part of this part of iSO 9614. Annexes C, D, E and F are for information only. ISO1996 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, withoutpermission in writing from the publisher. International Organizationfor Standardization CasePostale56·CH-1211Geneve20·Switzerland Printed in Switzerland ii oISO ISO 9614-2:1996(E) Introduction The sound power radiated by a source is equal in value to the inte- 0.1 gral of the scalar product of the sound intensity vector and the associated elemental area vector over any surface totally enclosing the source. Pre- vious International Standards which describe methods of determination of sound power levels of noise sources, principally ISO 3740 to IsO 3747, without exception specify sound pressure level as the primary acoustic and sound pressure level at any point depends on the characteristics of the source, the characteristics of the measurement environment, and the disposition of the measurement positions with respect to the source. Therefore IsO 3740 to ISO 3747 necessarily specify the source charac- teristics, the test environment characteristics and qualification procedures, uncertainty of the sound power level determination to within acceptable limits. ate,for the following reasons. Costly facilities are necessary if high precision is required. it is fre a) quently not possible to install and operate large pieces of equipment in such facilities. b) They cannot be used in the presence of high levels of extraneous 0.2 This part of IsO 9614 specifies methods of determining the sound power levels of sources, within specific ranges of uncertainty,under test IsO 3747. The sound power level is the in situ sound power level as de- function of the environment, and may in some cases differ from the sound power level of the same source determined under other conditions. It is recommended that personnel performing sound intensity meas- urements according to this part of IsO 9614 are appropriately trained and experienced. 0.3