丿 卩 丨NTERNAT|ONAL STANDARD Copyr€ht lnlerndional Organizalion lor Stan&rdrzaion Provided by IHS under liense wilh ISO No reprodudion or neMorkrre rermded w[hod f ense from IHS Mt lor Resate Iso 102[.]
丿卩 Iso 丨 NTERNAT|ONAL STANDARD 10291 First edition 1994-09-15 Glassin building- Determinationof steady-stateU values (thermal transmittance)sf multiple glazingGuardedhot plate method Verredansla construction- Ddterminationdu coeffrcientde transmission thermiqueU, en rdgime stationnairedes vitragesmultiples - Mdthode de la plaquechaudegardde Reference number lSO10291∶ Copyr€ht lnlerndional Organizalion lor Stan&rdrzaion Provided by IHS under liense wilh ISO No reprodudion or neMorkrre rermded w[hod f ense from IHS Mt lor Resate 1994(E) ∶ so10291:1994(E) Foreword I S O ( t h e l n t e r n a t i o n aO l r g a n i z a t i o nf o r S t a n d a r d i z a t i o ni s) a w o r l d w i d e f e d e r a t i o no f n a t i o n a ls t a n d a r d sb o d i e s( l S O m e m b e r b o d i e s ) T h e w o r k o f p r e p a r i n gI n t e r n a t i o n aSl t a n d a r d si s n o r m a l l yc a r r i e u t t h r o u g h I S O technical committees Each member body interested in a subject for w h i c h a t e c h n r c a cl o m m i t t e e h a s b e e n e s t a b l i s h e dh a s t h e r i g h t t o b e r e p r e s e n t e n t h a t c o m m i t t e e l n t e r n a t i o n aolr g a n i z a t i o n sg,o v e r n m e n t a l a n d n o n - g o v e r n m e n t nl , l i a r s o nw i t h l S O , a l s ot a k e p a r t i n t h e w o r k I S O c o l l a b o r a t e cs l o s e l y w i t h t h e l n t e r n a t i o n aEl l e c t r o t e c h n i c aCl o m m i s s i o n ( l E C )o n a l l m a t t e r so f e l e c t r o t e c h n i c a s tl a n d a r d i z a t i o n D r a f t l n t e r n a t i o n aSl t a n d a r d sa d o p t e d b y t h e t e c h n i c a lc o m m i t t e e s a r e ns a n I n t e r n a t i o n a l c i r c u l a t e dt o t h e m e m b e r b o d i e sf o r v o t i n g P u b l i c a t i o a S t a n d a r dr e q u i r e sa p p r o v abl y a t l e a s t7 o / oo f t h e m e m b e r b o d i e sc a s t i n g a vote l ommittee I n t e r n a t i o n aSl t a n d a r dI S O 1w a s p r e p a r e db y T e c h n i c a C ISO/TC 160, G/assin building,SubcommitteeSC 2, Use considerations o lso 1994 All rights reserved Unless otherwise specified, no part of this publication may be reproduced o r u t i l i z e di n a n y f o r m o r b y a n y m e a n s , e l e c t r o n i co r m e c h a n i c a li,n c l u d i n gp h o t o c o p y i n ga n d m i c r o f i l m w i t h o u t p e r m i s s i o ni n w r i t i n g f r o m t h e p u b l i s h e r I n l e r n a t i o n aO l rganization Jor Standardization C a s e P o s t a l e5 C H - 1G e n d v e o S w i l z e r l a n d Printed in Switzerland Copynght lnterndional Organization tor Standardizaton Provded by IHS under li@ne wih ISO M reprodudbn or newrking from IHS Frmfred wilhou [en* Ml tor Resab ∶ NTERNATlONAL sTANDARD◎ |SO ∶ so10291:1994(E) Gfass in building- Determinationof steady-stateU vafues(thermaltransmittancelof multipleglazingGuardedhot plate method Scope ISO 10292:1994 G/ass in building - Calculation of steady-state U values (thermal transmittance)of mul- T h i s I n t e r n a t i o n aS l t a n d a r d s p e c i ife s a m e a s u r i n g m e t h o d u s e d t o d e t e r m i n et h e c o e f f i c i e n ot f t h e r m a l t r a n s m r t t a n c et,h e U - v a l u e ,o f m u l t i p l e g l a z i n gw i t h f l a t a n d p a r a l l e ls u r f a c e s ,i n c l u d i n gc a s i a n d f i g u r e d r o l l e dg l a s s linla I t a p p l i e st o m u l t i p l eg l a z i n gw i t h o u t e r p a n e sw h i c h a r e n o t t r a n s p a r e ntto f a r - i n f r a r e dr a d i a t i o nw , hich is t h e c a s e f o r n o r m a lw i n d o w g l a s s H o w e v e ri n t e r n a l e l e m e n t sm a y b e f a r - i n f r a r etdr a n s p a r e n t Normative references T h e f o l l o w i n g s t a n d a r d sc o n t a i n p r o v i s i o n sw h i c h , t h r o u g h r e f e r e n c ei n t h i s t e x t , c o n s t i t u t ep r o v i s l o n s o i t h i s l n t e r n a t l o n aSl t a n d a r d A t t h e t i m e o f o u b l i c a t i o n ,t h e e d i t i o n si n d i c a t e dw e r e v a l i d A l l s t a n d a r d s a r e s u b j e c t t o r e v i s i o n ,a n d p a r t i e s t o a g r e e m e n t s b a s e d o n t h i s I n t e r n a t i o n aSl t a n d a r da r e e n c o u r a g e d t o i n v e s t i g a t et h e p o s s i b i l i t yo f a p p l y i n gt h e m o s t r e cent editions of the standards indicatedbelow M e m b e r s o i I E C a n d I S O m a i n t a i nr e g i s t e r so f c u r r e n t l yv a l i dI n t e r n a t i o n aSl t a n d a r d s ISO 8302:1991, Thermal insulation- Determination of steady-state thermal resistanceand related properties - Guardedhot plate apparatus Copyright Internaronal Orgadraton Ior Standardizarcn Provijed by IHS uder !@nse w(h ISO Mt lor Resab nlazina General T h i s l n t e r n a t i o n aSl t a n d a r dm a k e s o o s s i b l et h e d e t e r m i n a t i o no f t h e c o e f f i c i e n to f t h e r m a lt r a n s m i t t a n c e , t h e U - v a l u ei,n t h e c e n t r a la r e ao f t h e m u l t i p l eg l a z i n g E d g e e f f e c t s ,d u e t o t h e t h e r m a lb r i d g et h r o u g ht h e s p a c e ro f a s e a l e dg l a z i n gu n i t o r t h r o u g ht h e f r a m e a r e n o t i n c l u d e d N e i t h e r i s e n e r g y t r a n s f e rd u e t o s o l a rr a d i a t i o nt a k e n i n t o a c c o u n t T h e d e t e r m i n a t i o no f t h e c o e f fi c i e n t o f t h e r m a l t r a n s m i t t a n c ei s p e r f o r m e df o r c o n d i t i o n sw h i c h w i l l c o r r e s p o n dt o t h e a v e r a g e s i t u a t i o nf o r g l a z i n g i n practice In this way a fair comparisonbetween diff e r e n t p r o d u c t sb e c o m e sp o s s i b l e Basic equations and units The coefficientof thermal transmittance,the U-value, c f g l a z i n gc h a r a c t e r i z etsh e h e a t t r a n s f e rt h r o u g ht h e c e n t r a lp a r t o f t h e g l a z i n g ,i e w i t h o u t e d g e e f f e c t s , and defines the steady-statedensity of heat transfer p e r u n i t o f t i m e , p e r s u r f a c ea r e a u n i t a n d p e r t e m perature difference between the ambient temperatures on each side The U-valueis given in watts per s q u a r em e r r e k e l v i nt W / ( m ' ? K ) ◎ |So Iso10291:1994(E) + ⊥厶 + ⊥% 〓 R 1~σ TheU-valuedependson the thermalresistance of the multipleglazing andinternal andthe external surface heattransfercoefficients according to the following relation where 捋 h" s℃ Mn阿 watt m,田 is the external surface heat transfer coefficient, in watts per squaremetre kelvin ry7(m''r)l; ft, is the internalsurfaceheat transfercoefficient,in watts per squaremetre kelvin rwr(m'z.r)t l n a c c o r d a n c ew i t h t h i s I n t e r n a t i o n aSl t a n d a r d t h e t h e r m a l r e s i s t a n c eo f m u l t i p l e g l a z i n gi s m e a s u r e d using the guarded hot plate method The U-valueis t h e n d e r i v e df r o m e q u a t i o n( ) Brief outline Thespecimens shallbe of sucha sizeas to coverthe heatingunit surfacecompletely.Additionaledge inguardsectionsare required sulationand/orauxiliary as statedin ISO8302 Specimendimensions is the therma| resistance of the mu"ip|e uaremet叼 measures500 mm x 500 mm The coolingunits at leastas largeas thoseo{ havesurfacedimensions the guardheater the heatingunit,including of measuring method T h e t h e r m a l r e s i s t a n c eo f t h e m u l t i p l eg l a z i n gi s d e t e r m i n e db y m e a n s o f t h e g u a r d e dh o t p l a t e m e t h o d l a i d d o w n r n I S O , r e s p e c t i n gi t s d e t a i l e dr e c ommendations W i t h i n t h i s c o n t e x tf u r t h e r r e q u i r e m e n t sa r e n e c e s s a r y T h e s i z e s o f t h e t e s t s p e c i m e n sa n d t h e p e r f o r m a n c eo f t h e m e a s u r e m e n t sa r e l a i dd o w n t o m e e t s p e c i a lr e q u i r e m e n t sf o r m e a s u r i n gm u l t i p l eg l a z i n g s ( s e ec l a u s e s6 t o ) Test apparatus T h e s p e c i m e n s s h a l l b e s q u a r e a n d p r e f e r a b l yb e 800 mm x 800 mm The maximum range is from 750 mm x 750 mm to 850 mm x 850 mm T h e t w o s p e c i m e n sn e e d e d f o r m e a s u r e m e n ts h a l l b e a s n e a r l yi d e n t i c a la s p o s s i b l e T h e d i f f e r e n c ei n t h i c k n e s sb e t w e e n t h e t w o s p e c i m e n s ,m e a s u r e da t the edges, shall not be more than % his is also T h e s p e c i m e ns u r f a c e ss h a l l b e p a r a l l e lT requiredfor specimens with a textured surface (cast g l a s s ,f i g u r e dr o l l e dg i a s s ) I Preparation of specimens T h e s u m o f b o w i n g o r d i s h i n go f t h e o u t e r p a n e s i n the central area of the specimens shall not exceed , m m T h e c h e c k o f b o w i n g o r d i s h i n ge f f e c t ss h a l l be carried out after cooling the specimens until i s o t h e r m ael q u i l i b r i u mi s r e a c h e da t ' C , a n d b y m e a s u r i n g i m m e d i a t e l yb e f o r e t h e s p e c i m e n s a r e p o s i t i o n e di n t h e m e a s u r e m e n a t pparatus I n t h e c a s e o f t o o h i g h a b o w i n g , a c o r r e c t i o no f t h e t h i c k n e s so f t h e s p e c i m e n si n t h e c e n t r a la r e a m a y be made by a correspondingpressure reduction.ln t h e c a s e o f t o o h i g h a d i s h i n g ,a c o r r e c t i o nb y i n s e r t i o no f a i r i s o n l v a l l o w e di f t h e n e e d e dc o r r e c t i o n d o e s n o t e x c e e d0 m m The measurement equipment is a two-specimen app a r a t u s F i g u r e ' 1g i v e sa g e n e r a lo u t l i n eo f t h i s a p p a r a t u s i n c l u d i n g s o m e r e q u i r e m e n t ss p e c i f i c t o t h e m e a s u r e m e n ot f m u l t i p l eg l a z i n g s I T w o n e a r l yi d e n t i c a sl q u a r es p e c i m e n sa r e p l a c e de i ther side of a heatingunit The thermalflux flows t h r o u g ht h e s p e c i m e n st o t h e c o o l i n gu n i t s T o e n s u r es u f f i c i e n tc o n t a c tb e t w e e n t h e s p e c i m e n s and the adjacent surface plates, pieces of natural r u b b e rs p o n g ea b o u t m m t h i c k a r e u s e d T h e h e a t i n g u n i t c o n s i s t so f a s e p a r a t ec e n t r a lm e t e r i n g s e c t i o n ,w h e r e t h e u n i d i r e c t i o n ac lo n s t a n th e a t f l u x c a n b e e s t a b l i s h e ds u r r o u n d e db y a g u a r ds e c t i o n separated by a narrow gap The metering section M e a s u r e m e n t sa r e p e r f o r m e da t a m e a n t e m p e r a t u r e f o r e a c h s p e c i m e no f ( + , ) " C T h e m e a n t e m perature difference between the hot and cold specim e n s u r f a c e si s ( + ) ' C Crpyright Internalbnal Organrzatbn lor Sladardizalbn Pfovided by IHS under liense with ISO No reprodudion or newrkire Frmded wilhod [@ns kom IHS Measurements T h e m e a s u r e m e n t sa r e u s u a l l ym a d e w i t h t h e s p e c i mens venrcal ◎ |So ∶ so10291:1994(E) D i m e n s i o n si n m i l l i m e t r e s V Metering area heater B Metering area surfaceplates V A Guardsection Meteringsectionof heatingunit Guardsectionof heatingunit Guard surfaceplates E Coolingunits Ls Coolingunit surfaceplates I Specimens Rubbersponge r lnsulatingmaterial Figure - Copyright Internalbnal Organizatbn lor Slandadrzaton Prouded bv IHS under li@ns with ISO prmded wilhod license lrom lHS No reprodudion or reMrkng Measuringequipmentoutlins Not lor Resab ∶ so1o291△ ◎ |So 994(E) 10 Galculation and expression of resufts 10.1 Thermalresistanceof multipleglazing Thethermal per resistance, metres kelvin R,in square *att (.'.f/W), equatron: is calculated with the following glass).The correctedemissivityis determinedas in tso 10292 NOTE2 Valuesfor e lower than 0,837 (due to lowemissivitycoatings)shouldonly be taken into accountif watercondensation on the coatedsurfacecanbe excluded lmprovements of the U-valuedue to external-facing coated surfacesshouldnot be takenintoaccount 2A(7, _ T"\ R: :-_l -:j- .(2) lf other values of ft" and /r;are used to meet special conditions,these values shall be indicatedin the test repon wnere A is the metering area,in squaremetres; T1 is the averagespecimenhot side temperature,in kelvins; Tz is the averagespecimencold side temperature,in kelvins; @ is the averagepowersuppliedto the central sectionof the heatingunit,in watts 11 Test report Thetest reportshallindicatethe followingelements: a) identification of specimens: - length,in millimetres, 10.2 Coefficient of thermal transmittance - width,in miilimetres, The coefficient of thermaltransmittance U, is calcu(1) latedaccording to equation - thlcknessmeasured at the edges,in millime- For normalmultipleglazing,i.e glazingwithout a low-emissjvity coatingon the outersurface,the following values {or the surfaceheat trans{ercoefficientsare used: - thickness of the glasspanes,in millimetres, - thickness o{ gas space measuredat the edges,in millimetres, - - typeof gasfilling, - positionof any lR-reflecting coating(s), - bowingor dishing, in millimetres; internal surface heat transfer coefficient: : a wl(m'?'r) - external surface he: 23 wl(m'?'r) heat transfer coefficient: NOTE1 The reciprocai valuesof lo and 4, expressed to two significant decimals, areas follows: l l h e : , m ' K Wa n d1 l h , =0 , 3m K i W F o r m u l t i p l eg l a z i n gw i t h a l o w - e m i s s i v i tcyo a t i n gf a c ing inward, ftr, in watts per square metre kelvin, is m o d i f i e da c c o r d i n gt o t h e f o l l o w i n ge q u a t i o n : h,:3,6+ a'+0fu7 where a is the correctedemissivrty of the surfacefor room temperatureradiation(e:0,837 for window Copyright InlernalionalOrganizatbn for Sladardr2aton Provided by IAS under li@nse wfr ISO No reprodudaon or netuorkire Ermded wiltuff |ense iiom IHS Ml for Resab b) cross-section of the specimen: a figureshallshow the structureof the specimen(positionandthicknessof glasspanes,position andthickness of gas foils, typeof gasfilling,position of lnternal spaces, position of lR-reflecting coatings, etc.); c) measurement results: - meansurfacetemperatureon the hot side of the specimens, in kelvins, - meansurfacetemperature on the coldsideof the specimens, in kelvins, ◎ |S0 Iso10291:1994(E) - mean temperaturedifferencebetween the hot and cold sides of the specimens,in kelvins, - /r,and fte,in watts per square metre kelvin, if non-standardized values have been used, - mean temperature of the specimens, in kelvins, - U-value,in watts per square metre kelvin (to o n e d e c i m a lp l a c e ) - thermal resistance,in squaremetres kelvinper watt (to three significantfigures), Coptrighl Internarional Organization tor S€ft {drzAion Provded by IHS uder lcens with ISO No reprdudpn or reMorking permfred wrhout len* from tHS Not tor Resab Iso10291Hθ ◎ |so 94(E) lcs 81.040.20 D a s c r i p t o r s : c o n s t r u c t i o nm a t e r i a l s , t h e r m a l i n s u l a t i o n , g l a s s , p l a t e g l a s s , g l a z i n g , m u l t i p l eg l a z i n g , t h e r m o d y n a m i cp r o p e r t i e s , h e a t t r a n s f e r , t e s t s , d e t e r m i n a t i o n , t h e r m a l r e s r s t a n c e ,t h e r m a l m e a s u r e m e n t P r i c eb a s e d o n p a g e s Copyngm Internalional Organizaton lor Standerdrzafon with ISO Pro$ded by IHS under liens M reffodudDn or reMorkng Frmfied w(hod hcens irom l8S Mt for Resale