The cavity formed by the spacer bar between the two panes of glass in double-glazed units, is generally filled with air. The air can be replaced with argon for example, for enhanced thermal insulation or with sulphur hexafluoride for improved acoustic performance.

CE Marking means that the product complies with essential requirements of the Construction Products Directive drawn up by the European Commission, and that the product can be used for the application intended. To learn more about CE Marking, you can visit the GEPVP (Groupement Européen des Producteurs de Verre Plat) Website at www.gepvp.org.

See Enamelled glass.

Areas in close proximity to glazing, especially single-glazing, where exchange of heat by radiation can lead to the sensation of feeling cold or draughts.

Term given to the change in appearance of the natural colour of a material/object due to the colouration effect of light being transmitted through or reflected by the glass onto any given surface.

Process whereby gas or vapour turns into liquid by cooling. See Technical questions.

Glass used in guarding situations designed to withstand specified loads and prevent people from falling.

See Safety critical locations.

Recycled glass used in the manufacture of clear float glass.

Non-load bearing, typically aluminium, façade cladding system, forming an integral part of a building's envelope.

Glass, which is curved in form, produced by heating it to its softening point, so that it takes the shape of the mould. Annealed, toughened and laminated glass is available in curved form. See SGG CONTOUR.