ISO INTERNATIONAL STANDARD 10293 First edition 1997-02-15 Glass in building Determination of steady-state U values (thermal transmittance) of multiple glazing Heat flow meter method Verre dans la construction - Détermination du coefficient de transmission thermique, U, en regime stationnaire des vitrages multiples - Methode dufluxmetre ISO Reference number ISO 10293:1997(E) S010293:1997(E) Foreword iSO (the International Organization for Standardization) is a worldwide fed- preparing International Standards is normally carried out through isO which a technical committee has been established has the right to be represented on that committee. International organizations, governmental collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International a vote. International Standard iSO 10293 was prepared by Technical Committee IsO/TC16o,Glassinbuilding,SubcommitteeSC2,Useconsiderations @ISO1997 reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from the publisher. International Organization for Standardization Case postale 56 . CH-1211 Geneve 20 . Switzerland Internet [email protected] X.400 C=ch; a=40Onet; p=iso; O=isocs; S=central ii INTERNATIONALSTANDARD @ISO ISO 10293:1997(E) Glass in building Determination of steady-state U values (thermal transmittance) of multiple glazing - Heat flow meter method 1 Scope This International Standard specifies a measuring method used to determine the U value (thermal transmittance) of multiple glazing with flat and parallel surfaces. Structured surfaces, e.g. patterned glass, may be considered to be flat. This International Standard applies to multiple glazing with outer panes which are not transparent to far-infrared radiation which is the case for normal glass. However, internal elements may be far-infrared transparent. This International Standard allows the U value in the central area of the multiple glazing to be determined. Edge effects, due to the thermal bridge through the spacer of a sealed glazing unit or through the frame are not included. Furthermore, energy transfer due to solar radiation is not taken into account. The determination of the U value is performed for conditions which will correspond to the average situation for glazing in practice. In this way a fair comparison between different products is possible. 2 Normative references The following standards contain provisions which, through reference in this text, constitute provisions of this International Standard.At the time of publication, the editions indicated were valid.All standards are subject to sibility of applying the most recent editions of the standards indicated below. Members of IEC and iso maintain registers of currently valid International Standards. IS0 8301:1991, Thermal insulation - Determination of steady-state thermal resistance and related properties Heatflowmeterapparatus. Is0 8302:1991, Thermal insulation - Determination of steady-state thermal resistance and related properties Guarded hot plate apparatus. glazing.