ISO102911994scan

Copyr€htlnlerndionalOrganizalionlorStan&rdrzaionProvidedbyIHSunderliensewilhISONoreprodudionorneMorkrrerermdedw[hodfensefromIHSMtlorResateGlassinbuilding-Determinationofsteady-stateUvalues(thermaltransmittance)sfmultipleglazing-GuardedhotplatemethodVerredanslaconstruction-DdterminationducoeffrcientdetransmissionthermiqueU,enrdgimestationnairedesvitragesmultiples-MdthodedelaplaquechaudegarddeForewordISO(thelnternationalOrganizationforStandardization)isaworldwidefederationofnationalstandardsbodies(lSOmemberbodies).TheworkofpreparingInternationalStandardsisnormallycarriedoutthroughISOtechnicalcommittees.Eachmemberbodyinterestedinasubjectforwhichatechnrcalcommitteehasbeenestablishedhastherighttoberepresentedonthatcommittee.lnternationalorganizations,governmentalandnon-governmental,inliarsonwithlSO,alsotakepartinthework.ISOcollaboratescloselywiththelnternationalElectrotechnicalCommission(lEC)onallmattersofelectrotechnicalstandardization.DraftlnternationalStandardsadoptedbythetechnicalcommitteesarecirculatedtothememberbodiesforvoting.PublicationasanInternationalStandardrequiresapprovalbyatleast75o/oofthememberbodiescastingavote.InternationalStandardISO10291waspreparedbyTechnicalCommitteeISO/TC160,G/assinbuilding,SubcommitteeSC2,Useconsiderations.olso1994Allrightsreserved.Unlessotherwisespecified,nopartofthispublicationmaybereproducedorutilizedinanyformorbyanymeans,electronicormechanical,includingphotocopyingandmicrofilm.withoutpermissioninwritingfromthepublisher.InlernationalOrganizationJorStandardizationCasePostale56.CH-1211Gendve20oSwilzerlandPrintedinSwitzerlandCopynghtlnterndionalOrganizationtorStandardizatonProvdedbyIHSunderli@newihISOMreprodudbnornewrkingFrmfredwilhou[en*fromIHSMltorResabGfassinbuilding-Determinationofsteady-stateUvafues(thermaltransmittancelofmultipleglazing-Guardedhotplatemethod1ScopeThisInternationalStandardspecifiesameasuringmethodusedtodeterminethecoefficientofthermaltransmrttance,theU-value,ofmultipleglazingwithflatandparallelsurfaces,includingcasiandfiguredrolledglass.Itappliestomultipleglazingwithouterpaneswhicharenottransparenttofar-infraredradiation,whichisthecasefornormalwindowglass.Howeverinternalelementsmaybefar-infraredtransparent.2NormativereferencesThefollowingstandardscontainprovisionswhich,throughreferenceinthistext,constituteprovislonsoithislnternatlonalStandard.Atthetimeofoubli-cation,theeditionsindicatedwerevalid.Allstandardsaresubjecttorevision,andpartiestoagreementsbasedonthisInternationalStandardareencouragedtoinvestigatethepossibilityofapplyingthemostre-centeditionsofthestandardsindicatedbelow.MembersoiIECandISOmaintainregistersofcur-rentlyvalidInternationalStandards.ISO8302:1991,Thermalinsulation-Determinationofsteady-statethermalresistanceandrelatedprop-erties-Guardedhotplateapparatus.ISO10292:1994.G/assinbuilding-Calculationofsteady-stateUvalues(thermaltransmittance)ofmul-linlanlazina3GeneralThislnternationalStandardmakesoossiblethedeter-minationofthecoefficientofthermaltransmittance,theU-value,inthecentralareaofthemultipleglazing.Edgeeffects,duetothethermalbridgethroughthespacerofasealedglazingunitorthroughtheframearenotincluded.Neitherisenergytransferduetosolarradiationtakenintoaccount.Thedeterminationofthecoefficientofthermaltransmittanceisperformedforconditionswhichwillcorrespondtotheaveragesituationforglazinginpractice.Inthiswayafaircomparisonbetweendif-ferentproductsbecomespossible.4BasicequationsandunitsThecoefficientofthermaltransmittance,theU-value,cfglazingcharacterizestheheattransferthroughthecentralpartoftheglazing,i.e.withoutedgeeffects,anddefinesthesteady-statedensityofheattransferperunitoftime,persurfaceareaunitandpertem-peraturedifferencebetweentheambienttempera-turesoneachside.TheU-valueisgiveninwattspersquaremerrekelvintW/(m'?.K)1.CopyrightInternaronalOrgadratonIorStandardizarcnProvijedbyIHSuder!@nsew(hISOMtlorResabTheU-valuedependsonthethermalresistanceofthemultipleglazingandtheexternalandinternalsurfaceheattransfercoefficientsaccordingtothefollowingrelation.wheremeasures500mmx500mm.Thecoolingunitshavesurfacedimensionsatleastaslargeasthoseo{theheatingunit,includingtheguardheater.Thespecimensshallbeofsuchasizeastocovertheheatingunitsurfacecompletely.Additionaledgein-sulationand/orauxiliaryguardsectionsarerequiredasstatedinISO8302.7SpecimendimensionsThespecimensshallbesquareandpreferablybe800mmx800mm.Themaximumrangeisfrom750mmx750mmto850mmx850mm.Thetwospecimensneededformeasurementshallbeasnearlyidenticalaspossible.Thedifferenceinthicknessbetweenthetwospecimens,measuredattheedges,shallnotbemorethan2%.Thespecimensurfacesshallbeparallel.Thisisalsorequiredforspecimenswithatexturedsurface(castglass,figuredrolledgiass).IPreparationofspecimensThesumofbowingordishingoftheouterpanesinthecentralareaofthespecimensshallnotexceed0,5mm.Thecheckofbowingordishingeffectsshallbecarriedoutaftercoolingthespecimensuntilisothermalequilibriumisreachedat10'C,andbymeasuringimmediatelybeforethespecimensarepositionedinthemeasurementapparatus.Inthecaseoftoohighabowing,acorr