What is BS EN 674 – Thermal transmittance of building glass about?
BS EN 674 is a European Standard that has been prepared by Technical Committee CEN/TC 129 “Glass in building”, the secretariat of which is held by NBN.
BS EN 674 discusses the scope, references, definitions, formula, dimensions of the specimens, and much more in detail to ensure maximum efficiency.
BS EN 674 applies to multiple glazing with outer panes which are not transparent to far-infrared radiation, which is the case for soda lime silicate glass products, borosilicate glass, and glass-ceramics.
The document for the calculation of the overall U value of windows, doors, and shutters gives normative reference to the U value evaluated for the glazing components according to BS EN 674 . It also specifies a vertical position of the glazing is specified.
Note 1: The procedure specified in BS EN 674 should generally only be considered when the calculation method detailed in BS EN 673 is inappropriate or unsuitable.
Note 2: The edge effects, due to the thermal bridge through the spacer of an insulating glass unit or the window frame are not included. Furthermore, energy transfer due to solar radiation is not taken into account.
Who is BS EN 674 – Thermal transmittance of building glass