ISO INTERNATIONAL STANDARD 16957 First edition 2016-06-15 Measurement of apparent thermal conductivity of wet porous building materials by a periodic method Détermination de la conductivité thermique apparente des matériaux de construction poreux et mouillés par une méthode périodique Reference number IS0 16957:2016(E) ISO International Organization for Standardization e=ZHEJIANG INST OF STANDARDIZATION C1 5956617 @IS02016 vided by IHS under I No reproduction or networking permitted without license from IHS IS0 16957:2016(E) COPYRIGHT PROTECTED DOCUMENT 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 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 +41 22 749 09 47 [email protected] www.iso.org Internatinir DrganizationforStandardization Licensee-ZHEJIANG INST OF STANDARDIZzRoISQ6- All rights reserved Not for Resale, 2016/8/16 08:40:23 No reproduction or networking permited without license from IHS IS0 16957:2016(E) Contents Page Foreword ..iv Introduction. .. 1 Scope. ..1 2 Normative references ..1 3 Terms and definitions 4 Symbols and units ..2 5 Determination of thermal conductivity of a wet porous material by non-steady state method (periodic method) .3 Measurement by periodic method. 3 6 6.1 Test procedure .3 6.2 Measuring apparatus 4 6.2.1 Overall design 4 6.2.2 Generator of the sinusoidal or stepwise electric wave 4 6.2.3 Heater. .5 6.2.4 Specimen 5 6.3 Specimen preparation and preconditioning 5 6.3.1 Initial uniform moisture content and adiabatic and impermeable boundaries. 5 6.3.2 Embedding and the position of the thermocouples .5 6.4 Derivation of thermal diffusivity from measured temperatures (see Annex B) 5 6.4.1 Solution for heat flow without moisture. .5 6.4.2 Solution for heat flow with moisture 6 6.5 Estimation of measuring uncertainty due to moisture (vapour) movement .7 6.6 Thermal conductivity 7 Test report .7 Annex A (informative) Theoretical background .9 Annex B (informative) Derivation of thermal conductivity from measured temperatures ..11 Annex C (informative) Example of measurement by periodic method ..17 Bibliography .20 ii e=ZHEJIANG INSTOF STANDARDIZATION C1 5956617 thout license from IHS