SR EN 673:2024

This document specifies a calculation method to determine the thermal transmittance of glass with flat and parallel surfaces. This document applies to uncoated glass (including glass with structured surfaces, e.g. patterned glass), coated glass and materials not transparent in the far infrared which is the case for soda lime glass products, borosilicate glass, glass ceramic, alkaline earth silicate glass and alumino silicate glass. It applies also to multiple glazing comprising such glasses and/or materials. It does not apply to multiple glazing which include in the gas space sheets or foils that are far infrared transparent. The procedure specified in this document determines the U value (thermal transmittance) in the central area of glazing. The edge effects due to the thermal bridge through the spacer of an insulating glass unit or through the window frame are not included. Furthermore, energy transfer due to solar radiation is not taken into account. The effects of Georgian and other bars are excluded from the scope of this document. NOTE EN ISO 10077 1:2017 provides a methodolog