How Float Glass is made
The main components of ‘Float Glass’ are Soda Lime Glass, Silica Sand (73%), Calcium Oxide (9%), Soda (13%) and Magnesium (4%). These components are mixed into batches and recycled glass (cullet) is added.
The batched raw materials pass from a mixing silo to a furnace where they become molten at a temperature of approximately 1500°C. The molten glass is then “Floated” onto a bath of molten tin at a temperature of about 1000°C. The glass, being highly viscous, and the tin, which is very fluid, do not mix and the contact surface between these two materials remain perfectly flat.
The glass leaves the bath of molten tin at a temperature of 600°C and entersan annealing chamber called “Lehr”. The process of annealing modifies the glass and the internal stresses so it can easily be cut and worked as required.
After the Lehr, the glass is allowed to cool to a manageable temperature. Quality checks are then performed, the glass washed, cut into manageable sizes and stacked.
Safety Glass is basically a strengthened glass that provides a higher level of durability and resistance to breakage from impact or otherwise.
There are two types of Safety Glass in Australia, A-Grade and B-Grade. The most commonly used is A-Grade safety glass, which is required by Australian Standards (AS1288) in many circumstances. In non-critical situations, B-Grade safety glass maybe applicable. Refer to your qualified builder or the ABCB (www.abcb.gov.au) for the exact requirements to suit your individual installation.