ISO INTERNATIONAL STANDARD 16254 First edition 2016-05-01 Acoustics Measurement of sound emitted by road vehicles of category M and N at standstill and low speed operation Engineering method Acoustique Mesurage du bruit émis par les vehicules routiers de categories M et N a I'arret et en fonctionnement a basse vitesse Méthode d'expertise Reference number ISO 16254:2016(E) ISO International Organization for Standardization @ IS0 2016 HEJIANG INST OF STANDARDIZATION C1 5956617 vided by IHS under ed without license from IHS IS0 16254:2016(E) COPYRIGHTPROTECTEDDOCUMENT IS0 2016, Published in Switzerland All rights reserved. Unless otherwise specified, 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 or ISO's member body in the country of the requester. ISO copyright office Ch. de Blandonnet 8 . CP 401 CH-1214 Vernier, Geneva, Switzerland Tel. +41 22 749 01 11 Fax+412274909 47 [email protected] www.iso.org Intenationai br PrganizationforStandardization icensee-ZHEJIANG INST OF STANDARDIZoISQ s.6 - All rights reserved Not for Resale, 2016/7/20 08:11:04 etworking permitted without license from IHS IS0 16254:2016(E) Contents Page Foreword ..V Introduction. ...vi 1 Scope 2 Normative references 3 Terms and definitions 4 Symbols and abbreviated terms ..3 5 Instrumentation. ..4 5.1 Instruments for acoustic measurement .4 5.1.1 General. ..4 5.1.2 Calibration .5 5.1.3 Compliance with requirements 5.2 Instrumentation for speed measurements ..5 5.3 Meteorological instrumentation .5 6 Acoustic environment, meteorological conditions, and background noise 6.1 Test site. .6 6.1.1 General. 6.1.2 Outdoor testing .6 6.1.3 Indoor hemi anechoic or anechoic testing ..7 6.1.4 Indoor external sound generation system testing. .9 6.2 Meteorological conditions. .9 6.2.1 General. .9 6.2.2 Outdoor measurements .9 6.2.3 Indoor measurements. 6.3 Background noise .9 6.3.1 Measurement criteria for A-weighted sound pressure level 6.3.2 Vehicle A-weighted sound pressure level measurement correction criteria .10 6.3.3 Background noise requirements when analysing in one-third-octave bands 6.3.4 Measurement background noise when testing a component .12 7 Test procedures .12 7.1 Full vehicle testing. ..12 7.1.1 Microphone positions. ..12 7.1.2 Conditions of the vehicle .12 7.1.3 Test mass of vehicle... ..13 7.1.4 Tyre selection and condition .13 7.1.5 Operating conditions. ..13 7.1.6 Measurement readings and reported values .15 7.1.7 Data compilation. .16 7.1.8 Standstill results. .16 7.1.9 Slow speed cruise result at 10 km/h ..16 7.1.10 Reported value ..16 7.2 Measurement of sound to determine frequency shift ..16 7.2.1 General .16 7.2.2 Instrumentation .17 7.2.3 Signal processing requirements. ..17 7.2.4 Test facilities .17 7.2.5 Frequency shift measurement test procedure .17 7.3 Measurement uncertainty ..20 8 Test report. ..21 Annex A (informative) Information on development of Is0 16254 ..22 AnnexB (informative) Development offrequency shift information .24 ntemaonalgnzat@All rights reserved iii nsee=ZHEJIANG INST OF STANDARDIZATION C1 5956617 d without license from IHS Not for Resale, 2016/7/20 08:11:04