Float glass is produced by melting sand, soda-ash, limestone and dolomite in a furnace, and sometimes also mixing in recycled glass. The furnace outputs a continuous ribbon of molten glass that is floated onto a large bed of molten tin. This mixture slowly solidifies to a thickness controlled by the speed it is drawn over the molten tin. It is then annealed – control cooled – to ensure flatness.
Clear Float Glass
Clear float glass is transparent and colourless, offering high visible light transmittance and optical clarity. It offers little resistance to solar heat gain and glare in buildings.
Toned Float Glass
Toned float glass is produced by adding a colourant, usually powdered oxides, into the furnace. It is primarily designed to reduce solar heat gain and glare, which from an occupant's point of view increases the comfort level and can reduce cooling costs.
Laminated glass is safety glass that has been manufactured by adhering two or more sheets of glass with a flexible interlayer. This interlayer, usually 0.38mm thick and manufactured from poly vinyl butyral (PVB), prevents the glass from disintegrating when broken.
Toughened glass is produced by passing cut-to-size annealed float glass through a heat furnace. This process introduces stress into the glass and produces a glass 4-5 times stronger than ordinary float glass. Toughened glass can still be broken, however if this does happen it shatters into small fragments, minimising the risk of injury caused by glass splinters.
Insulating Glass Units (IGUs)
Insulating glass units (also referred to as double glazed units) consist of two panes of glass separated by a spacer around the edges and sealed to the perimeter in factory controlled conditions. The spacer contains a desiccant which eliminates moisture vapour in the cavity. Insulating glass units are available in many glass combinations, and the air gap between the glass panes can be filled with a range of gases.
Low emissivity (Low-E) Glass
Low-E glass has a low rate of emission – that is it has a lower rate than clear float glass of allowing heat to pass through the glass. In other words, if there is a heat source inside your house (or outside), the glass bounces the heat from that object back away from the glass.