Windows in your home might typically use standard annealed glass, but sometimes they also use other types, such as laminated or toughened glass, particularly if they are generously sized. Each of these breaks differently, so you can judge what type a window uses by how this happens.
Annealed Glass
Annealed or float glass is the standard kind used in regular sized windows. It is called float glass because during production, the molten glass mixture floats along a bath of melted metal (typically tin) as it cools and hardens to produce uniform sheets. Double glazed windows, which consist of two glass panes bonded on either side of a centre space filled with gas or air, often use this glass as well, though other glass types can combine also. If one of your window panes breaks into large, pointy shards, there is a good chance that it is annealed glass, as this is its standard breakage pattern.
Toughened Glass
Large feature or full-length windows sometimes use toughened glass instead, which is about four to five times more robust than float glass. Toughened glass begins life as float glass, but it undergoes a unique tempering process to make it incredibly durable. This process involves heating and cooling a standard pane. An oven heats it to extreme temperatures, then chilled air blasts the surface. Because the inner and outer parts of the glass cool at different rates, it undergoes physical changes that make it super durable. Additionally, this glass breaks in a safe pattern; if you have a window that crumbles or shatters into evenly sized square cubes, rather than pointy shards, it might well be toughened glass.
Laminated Glass
Laminated glass also starts out as ordinary float glass. It consists of two glass panes bonded together with an interlayer of polymeric material to create a single sandwich. Full-length windows or oversized windows might use laminated glass. An added advantage is that manufacturers can embed different technologies into the interlayer to muffle noise, to block sun glare, or to resist fire, which helps the glass to perform other roles. Laminated glass is more robust than one glass pane on its own. Also, if it breaks, the resin-type interlayer tends to hold the broken glass in place, which helps to prevent injuries caused by loose glass pieces. It ensures that the barrier, though cracked, stays in place until professional in repairing windows is at hand.
