ISO INTERNATIONAL STANDARD 18081 First edition 2016-06-01 Non-destructive testing Acoustic emission testing (AT) Leak detection by means of acoustic emission Essais non destructifs - Controle par émission acoustique - Détection de fuites par émission acoustique Reference number ISO 18081:2016(E) ISO International Organization for Standardization see=ZHEJIANG INST OF STANDARDIZATION C1 5956617 @ISO2016 ermitted without license from IHS IS0 18081:2016(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. ISOcopyrightoffice Ch. de Blandonnet 8 · CP 401 CH-1214 Vernier, Geneva, Switzerland Tel. +41 22 749 01 11 Fax +41 22 749 09 47 copyright@iso.org www.iso.org Internationai ibrg DrganizationforStandardization Licensee-ZHEJIANG INST.OF STANDARDIZzRoISQ6- All rights reserved Not for Resale, 2016/7/20 07:49:23 networking permited withoutlicense from IHS IS0 18081:2016(E) Contents Page Foreword ..V 1 Scope .1 2 Normative references 3 Terms and definitions 4 Personnel qualification. ..2 5 Principle of acoustic emission method ..2 5.1 The AE phenomenon. .2 5.2 Influence of different media and different phases ..3 5.3 Influence of pressure differences. .4 5.4 Influence of geometry of the leak path 5.5 Influence of wave propagation .4 6 Applications ..5 7 Instrumentation .5 7.1 General requirements 7.2 Sensors. .5 7.2.1 Typical frequency ranges (band widths) .5 7.2.2 Mounting method. .6 7.2.3 Temperature range, wave guide ..6 7.2.4 Intrinsic safety .6 7.2.5 Immersed sensors .6 7.2.6 Integral electronics (amplifier, RMS converter, ASL converter, band pass) ..6 7.3 Portable and non-portable AT instruments. ·6 7.4 Single and multichannel AT equipment. 7.4.1 Single-channelsystems .6 7.4.2 Multi-channel systems. ..6 7.5 Measuring features (RMS, ASL vs. hit or continuous AE vs. burst AE) 7 7.6 Verification using artificial leak noise sources. 7 8 Test steps for leak detection 8.1 Sensor application 7 8.2 Measured features. ..8 8.3 Background noise. ..8 8.3.1 Environmental noise .8 8.3.2 Process noise ..8 8.4 Data acquisition ..8 9 Location procedures. .9 9.1 Generalconsiderations .9 9.2 Single sensor location based on AE wave attenuation .9 9.3 Multi-sensor location based on At values (linear, planar) 9.3.1 Threshold level and peak level timing method .9 9.3.2 Cross correlationmethod 10 9.4 Wave type and wave mode based location .11 10 Data presentation .11 10.1 Numerical data presentation (level-meter) 10.2 Parametric dependent function (e.g. pressure) ..1 10.3 Frequency spectrum ..12 11 Data interpretation ..12 11.1 Leakvalidation ..12 11.1.1 On-site (during test) and off-site (post analysis) ..12 11.1.2 Correlation with pressure ..12 11.1.3 Rejection of false indications. .12 ntemaional oganzation@sS26-All rights reserved ii: Licensee=ZHEJIANG INST OF STANDARDIZATION C1 5956617 vided by IHS under license with ISC No reproduction or networking permi ed without license from IHS