Thermal and solar properties

Where glazing is to be used in applications where energy conservation is important, the thermal transmittance (U-value), light transmission (%), light reflectance and solar factor (g-value) properties of the glass and coatings should be specified.

Testing in accordance with BS EN 410, BS EN 673 and BS EN 12898 is specified within the product conformity standards for most glasses to be used in construction.

We carry out testing in accordance with these standards. See our initial type testing of glass construction products.

Please contact us, or make an enquiry using the form above, if you have any bespoke requirements, require further information, or would like a quote for analysis.

For further information, please see:

Gas Concentration and Gas Leakage

We are also able to measure the argon gas concentration using non-destructive methods on insulating glass units sent to our laboratory. The gas concentration can be compared with the requirements in BS EN 1279 part 3 Long term test method and requirements for gas leakage rate and for gas concentration tolerances. This service forms part of our overall product verification service where specified product performance can be compared with delivered product performance in buildings. Argon gas is primarily used to reduce heat loss in insulating units and the concentration level has a direct impact on the thermal performance and running costs of a building.


  • BS EN 410, 'Glass in building. Determination of luminous and solar characteristics of glazing';
  • BS EN 673, 'Glass in building. Determination of thermal transmittance (U value). Calculation method';
  • BS EN 12898, 'Glass in building. Determination of the emissivity';
  • ISO 9050:2003, 'Glass in building. Determination of light transmittance, solar direct transmittance, total solar energy transmittance, ultraviolet transmittance and related glazing factors';
  • BS ISO 13837:2008, 'Road vehicles. Safety glazing materials. Method for the determination of solar transmittance';
  • BS EN 1279-3:2002, 'Glass in building. Insulating glass unitsLong term test method and requirements for gas leakage rate and for gas concentration tolerances'.

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