ISO INTERNATIONAL STANDARD 13789 Third edition 2017-06 Thermal performance of buildings Transmission and ventilation heat transfer coefficients Calculation method Performance thermique des batiments - Coefficients de transfert de chaleur par transmission et par renouvellement d'air - Méthode de calcul Reference number ISO 13789:2017(E) International Organization for Standardization @ IS0 2017 ZHEJIANG INSTOFSTANDARDIZATION C15956617 vided by IHS under ted without license from IHS IS0 13789:2017(E) COPYRIGHTPROTECTEDDOCUMENT IS02017,PublishedinSwitzerland 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 Intenationaibr PrganizationforStandardization icensee-ZHEJIANG INST.OF STANDARDIZRoISQ s1.7 - All rights reserved Not for Resale, 2017/9/12 02:46:54 etworking permitted without license from IHS IS0 13789:2017(E) Contents Page Foreword ..iv Introduction. ..V 1 Scope. .1 2 Normative references 3 Terms and definitions ..2 4 Symbols and subscripts. ..4 4.1 Symbols .4 4.2 Subscripts. .4 5 Description of the method .5 5.1 Output. .5 5.2 General description. .5 6 Calculation of heat transfer coefficients .5 6.1 Outputdata .5 6.2 Calculation time intervals .7 6.3 Inputdata. .7 6.4 Measurementofdimensions .8 6.5 Boundaries of conditioned space ..8 7 Transmission heat transfer coefficient .10 7.1 Basicformula .10 7.2 Mean thermal transmittance of building fabric. ..10 7.3 Direct transmission between internal and external environments .11 7.4 Transmission heat transfer coefficient through the ground. .12 7.5 Transmission heat transfer coefficient through unconditioned spaces ..12 7.6 Heat transfer to adjacent buildings .13 8 Ventilation heat transfer coefficient .14 9 Additional conventions. .14 9.1 General. .14 9.2 Transmission heat transfer coefficient through the ground .14 9.3 Variable thermal transmittance .14 9.4 Air change rates of unconditioned spaces. ..14 9.5 Conventional values of surface heat transfer coefficient. .15 10 Report ..16 Annex A (normative) Input and method selection data sheet - Template ..17 Annex B (informative) Input and method selection data sheet - Default choices ..20 Annex C (normative) Temperature in an unconditioned space ..23 Bibliography .24 iii =ZHEJIANG INST OF STANDARDIZATION C1 5956617 withoutlicense from IHS