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Heat transmission through framed windows

Objective



The results of a previous intercomparison in which measurements of heat transmission were made on two different sized double-glazed window units (without frames) showed rather large discrepancies between the different laboratories. In this latest intercomparison, seven double-glazed reference panel units and seven double-glazed framed windows were circulated and measurements were made under commonly agreed and very detailed specified conditions. The reference panels had a rigid foam insulation material between the panes because a particular problem in the previous intercomparison had been the variation in the thickness of the airgap between the panes. Each participating laboratory made measurements on one panel unit and one window using a guarded hot box apparatus.

RESULTS

The standard deviation about the mean of the standardised U-values was about 5% for the reference panels and about 7% for the windows. Excluding outliers where reasons for discrepancies could be postulated, the range of the standardised U-values was 2.03 to 2.29 W/m{2} K for the reference panels and 2.46 to 2.84 W/m{2} K for the windows.

Coordinator

Forschungsinstitut für Wärmeschutz eV
Address
Lochhamer Schlag 4
82166 München-gräfelfing
Germany

Participants (10)

British Board of Agreement
United Kingdom
CENTRE SCIENTIFIQUE ET TECHNIQUE DE LA CONSTRUCTION
Belgium
Centre Experimental de Recherches et d'Etudes du Batiment et des Travaux Publics (CEBTP)
France
Centre Scientifique et Technique du Bâtiment (CSTB)
France
Fraunhofer-Gesellschaft zur Förderung der Angewandten Forschung eV (FhG)
Germany
Address
Nobelstraße 12
70569 Stuttgart
Institut für Fenstertechnik
Germany
Istituto Centrale per l'Industrializazione della Tecnologia Edilizia
Italy
National Physical Laboratory (NPL)
United Kingdom
Address
Queen's Road
TW11 0LW Teddington
Pilkington plc
United Kingdom
Toegepast Natuurwetenschappelijk Onderzoek
Netherlands