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.
BS EN 674 on The guarded hot plate method is useful for:
Glass in buildings needs to be tempered for optimum insulation and to balance the temperature. There is a high demand for such glasses. Using thermal transmittance by the guarded hot plate method can ensure the high performance of glass in buildings.
BS EN 674 specifies a measurement method to determine the thermal transmittance of glazing with flat and parallel surfaces using the guarded hot plate method. Structured surfaces, e.g., patterned glass, can be considered to be flat. Internal elements may be far-infrared transparent. The procedure specified in BS EN 674 determines the (U value) thermal transmittance in the central area of glazing. As standardization is important to assure temperature accuracy, BS EN 674 helps you for accurate measurement and optimum credibility.
EN 674:2011