ISO INTERNATIONAL STANDARD 354 Second edition 2003-05-15 Acoustics Measurement of sound absorption in a reverberation room Acoustique Mesurage de I'absorption acoustique en salle réverberante Reference number ISO 354:2003(E) ISO @ ISO 2003 IHS unde Not for Resale ISO354:2003(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 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 that a problem relating to it is found, please inform the Central Secretariat at the address given below. ?ISO2003 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, IsO's memberbody 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.org Published in Switzerland Copyihtinteratinal organization for Standardization @ ISO 2003 - All rights reserved itted without license from IHS Not for Resale ISO 354:2003(E) Contents Page Foreword Introduction 1 Scope 2 Normative references 3 Terms and definitions 4 Principle. 5 Frequency range 6 Testarrangement... 6.1 Reverberation room and diffusion of sound field 6.2 Test specimens .. 6.3 Temperature and relative humidity 7 Measurement of reverberation time 7.1 General. 7.2 Interrupted noisemethod.. 7.3 Integrated impulse response method 7.4 Evaluation of reverberation times based on decay curves... 8 Expression of results.... 8.1 Method of calculation 8.2 Precision.... 8.3 Presentation of results 12 9 Test report 13 Annex A (normative) Diffusivity of the sound field in the reverberation room.. 14 Annex B (normative) Test specimen mountings for sound absorption tests 15 Bibliography 2* ii from IHS Not for Resale ISO354:2003(E) Foreword Iso (the International Organization for Standardization) is a worldwide federation of national standards bodies technicalcommittees.Eachmemberbodyinterestedinasubjectforwhichatechnicalcommitteehasbeen 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 Standards are drafted in accordance with the rules given in the ISO/lEC Directives, Part 2. adopted by the technical committees are circulated to the member bodies for voting. Publication as an International 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 354 was prepared by Technical Committee ISO/TC 43, Acoustics, Subcommittee SC 2, Building acoustics. This second edition cancels and replaces the first edition (IsO 354:1985), which has been technically revised, asfollows: an integrated impulse response method has been introduced; therequirementtomeasureatleast36decayshasbeenadded; have been introduced. @ ISO 2003 - All rights reserved ISO 354:2003(E) Introduction When a sound source operates in an enclosed space, the level to which reverberant sound builds up, and the subsequent decay of reverberant sound when the source is stopped, are governed by the sound-absorbing characteristics of the boundary surfaces, the air filling the space, and objects within the space. In general, the fraction of the incident