What is BS EN 673 - Thermal transmittance of glass about?
BS EN 673 is a European Standard that discusses scope, definitions, emissivity, glazing, and much more in detail to assure high performance.
BS EN 673 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, and glass-ceramic.
BS EN 673 also applies to multiple glazing comprising such glasses and/or materials.
Note 1: BS EN 673 for the calculation of the overall U value of windows, doors, and shutters (see EN ISO 10077-1 [1]) gives normative reference to the U value calculated for the glazing components according to BS EN 673.
Note 2: BS EN 673 does not apply to multiple glazing which includes the gas space sheets or foils that are far infrared transparent.
Note 3: For product comparison, a vertical position of the glazing is specified. In addition, U values are calculated using the same procedure for other purposes, in particular for predicting: heat loss through glazing; conduction heat gains in summer; condensation on glazing surfaces; the effect of the absorbed solar radiation in determining the solar factor (see Bibliography, [2])
Note 4: Reference should be made to [3], [4] and [5] or other European Standards dealing with heat loss calculations for the application of glazing U values determined by BS EN 673
Note 5: The edge effects due to the thermal bridge through the spacer of a sealed glazing unit or the window frame are not included. Furthermore, energy transfer due to solar radiation is not taken into account.
Note 6: The effects of Georgian and other bars are excluded from the scope of BS EN 673
Who is BS EN 673 - Thermal transmittance of glass for?
BS EN 673 on Thermal transmittance of glass is relevant to:
- Tempered Glass manufacturers
- Glass Technologists
- Building Constructors and Engineers
- Architects
- Property and Building Directorates
- Entities involved in Building Research and Development
Why should you use BS EN 673 - Thermal transmittance of glass?
A standardized method for the determination of thermal transmittance is necessary to ensure maximum credibility. Thermal transmittance is of primary importance as it maintains the energy balance of efficient buildings.
BS EN 673 specifies a calculation method to determine the thermal transmittance of glazing with flat and parallel surfaces. The procedure specified in BS EN 673 determines the U value1) (thermal transmittance) in the central area of glazing.
Standardized processes of thermal transmittance help bring uniformity to all glasses, thus opening up a bigger market. Use BS EN 673 to guarantee state-of-the-art glass in the building. BS EN 673 can also ensure maximum safety and credibility.
What’s changed since the last update?
BS EN 673:2011 supersedes BS EN 673:1998, which is withdrawn. BS EN 673:2011 includes some changes with respect to BS EN 673:1998. These include:
- The internal and external heat transfer coefficients have been amended slightly to avoid any ambiguities
- The original annex on the determination of emissivity has been removed and reference is made to EN 12898
- Other changes include the incorporation of amendments A1 and A2 and general improvements to the text to aid understanding
