ISO INTERNATIONAL STANDARD 14257 First edition 2001-10-15 Acoustics Measurement and parametric description of spatial sound distribution curves in workrooms for evaluation of their acoustical performance Acoustique Mesurage et description paramétrique des courbes de décroissance sonore spatiale dans les locaux de travail en vue de I'évaluation de leur performance acoustique Reference number ISO 14257:2001(E) (So @ ISO 2001 ISO 14257:2001(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 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 @ ISO 2001 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-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 2001 - All rights reserved ISO 14257:2001(E) Contents Page Foreword. Introduction 1 Scope 2 Normative references Terms and definitions 4 Sound distributionina room.. 4.1 4.2 Spatial sound distribution curves 5 Measurement of the spatial sound distribution curve. 5.1 Specifications regarding the sound source used for the test, 5.2 Measurementinstrumentation. 5.3 Measurementpathandpoints. 5.4 Measurement procedure.. 5.5 Representation of the measured data . 8 6 Parametric description of the measured spatial sound distribution curve in view of evaluation of the acoustical performance of workrooms 6.1 General.... 6.2 Distance ranges. 6.3 Determination of the rate of spatial decay of sound pressure levels per distance doubling, DL2 .....9 6.4 Determination of the excess of sound pressure level with respect to a reference sound distribution curve, DLf .. 6.5 Evaluation of measured data.. ..12 7 Information to be recorded and reported. 12 Annex A (normative) Performance requirements for the sound source to be used for the test. ..14 Annex B (normative) Correction of measured sound distribution curves to account for differences in ground reflections and source directivity.. Annex C (informative) Example of use of this International Standard .. 17 Bibliography 25 nserved ili