ISO INTERNATIONAL STANDARD 3740 Third edition 2019-02 AcousticsDeterminationof sound power levels of noise sources Guidelines for the use of basic standards Acoustique-Determinationdesniveauxdepuissanceacoustique émisparlessourcesdebruit-Lignes directricespourI'utilisation des normesdebase Reference number ISO3740:2019(E) ISO @IS02019 IS03740:2019(E) COPYRIGHTPROTECTEDDOCUMENT @ISO2019 All rights reserved. Unless otherwise specified, or required in the context of its implementation, 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 on the internet or an intranet, without prior written permission. Permission can be requested from either IsO at the address below orIso's memberbody in the countryof therequester. ISO copyright office CP 401 : Ch. de Blandonnet 8 CH-1214 Vernier, Geneva Phone:+41227490111 Fax:+4122749 09 47 Email: [email protected] Website: www.iso.org Published in Switzerland ii @ IS0 2019- All rights reserved IS03740:2019(E) Contents Page Foreword ..iv Introduction. ..V 1 Scope. .1 2 Normative references ..1 3 Terms and definitions .1 4 Sound power level .1 4.1 Basic information .7 4.2 Reasonsforthedetermination ofsoundpowerlevels .7 4.3 Basic procedures for determining sound power levels 1 4.4 Qualityofdeterminedsoundpowerlevels. .8 4.5 Noise emission declaration. .8 5 Selection of the most appropriate method in the set of standards .9 5.1 Methodsandguantitiestobemeasuredanddetermined .9 5.2 Considerations affecting the selection of a measurement method .9 5.3 Test environment ..17 5.4 Selection of basic standards appropriate for measurements in laboratory rooms and specialtestrooms. ..17 5.4.1 General ..17 5.4.2 Acoustical requirements on the sound field in laboratories and special testrooms ..17 5.4.3 Background noiselimitation .17 5.5 Selection of basic standards appropriatefor in-situ measurements 18 5.5.1 General. .18 5.5.2 Hemi-anechoic sound field check .19 5.6 Determination ofhigh-frequency sound power levels 20 Annex A (informative) Basic International Standards specifying methods for determining sound power ievels of machines,equipmentandproducts-Mainfactsand reguirements .21 AnnexB (informative)Acousticaltestenvironments .23 Annex C (informative)Measurement uncertainty .25 Annex D (informative)Case studies ..28 Bibliography .34 @IS0 2019-All rights reserved ili