The Double Glazing Glossary

Thermally insulating glazing : Double-glazed units provide thermal insulation. See also "enhanced thermal insulation" and "Document L".

Toughened glass : Toughened Glass is made by a controlled heating and cooling process in order to significantly increase its resistance to mechanical and thermal stress. This thermal toughening process helps the glass to gain its safe-breakage characteristics.

Trustmark : The TrustMark scheme is supported by the Government, the building industry and consumer groups to help customers find reliable and trustworthy tradespeople thereby giving them a complete peace of mind.