Annealed or float glass is the most common type of glass. It is versatile enough to be used in a variety of settings and serves as the basis for many other types of glass, such as tinted (heat-absorbing) glass and laminated glass.
How is Float Glass Made?
Float glass is made using the float process (also known as the Pilkington process). The method involves pouring molten glass from a furnace onto a shallow bath of molten tin at a temperature of around 1000°C. The molten glass floats on top of the tin, spreading out to create an even surface. The pace at which the solidifying glass ribbon is taken out of the bath determines the thickness. The glass emerges as a ‘fire’ polished product with nearly parallel surfaces after annealing (controlled cooling).
How Long Has Float Glass Been Around?
Float glass was invented in 1951 by Sir Alastair Pilkington. Before the float process, most modern flat glass was made using plate-glass making process.
Advantages of Float Glass
- It is aesthetically pleasing, due to its smoothness and lack of distortion
- It is versatile enough to be used in a variety of applications, including windows, sliding doors, shopfront displays etc
- The transparent quality makes it suitable for many applications where transparency is required, such as shop fronts.
How Does Float Glass Compare to Other Types of Glass?
Float glass is cheaper than laminated and toughened glass but has limited strength in comparison. It is also less scratch resistant and when broken, it shatters into sharp shards that can cause severe injury. This is the reason AS1288-2006 requires safety glass to be installed in place of regular float glass in areas where their is a high risk of human impact such as doors and shower screens.