Much of the glass in a home is constructed from one type or another of safety glass. The benefits of these types of glass are that they are less inclined to break, and when they do, they are unlikely to cause injury. You might have had a breakage in your home and are not sure what type it is. Expert glass repairers will be on top of it all, so you don't have to worry. However, you can often tell the glass type just by the way it breaks, as the way this occurs leaves clues which you can read.
It Crumbles Into Small Blunt Pieces
You might have glass shower screens or a glass door that has broken. So how can you tell what type of glass it is? If the whole panel crumbles or disintegrates into blunt, cube-like pieces, this glass might be toughened glass. This form of glass, in the event of an accident, is designed to break in a safe way that is unlikely to cause injury. So rather than breaking up into pointy shards, it will crumble into relatively even-sized, rounded pieces. The whole panel will disintegrate in this way. Half the panel won't break, for instance, and the other half stay in place. Toughened glass is about four or five times stronger than ordinary glass, so it is unlikely to break in the first place. But if your broken shower screen or door shows these signs, it could be toughened safety glass. Alternatively, this might not describe your situation at all, and it might be another type altogether.
It Fractures But Holds Together As One Piece
You might have noticed a different situation with your broken glass. It might show cracks that form a spiderweb pattern, but everything is staying together as one piece. It is not breaking up into bits and pieces. If your glass is behaving in that way, it might be laminated glass. This consists of two glass panes bonded together, with heat and pressure, by an interlayer of Polyvinyl Butyral (PVB). When it breaks, the plastic interlayer holds all the fractured pieces together. This keeps the broken glass pieces intact and unlikely to injure bystanders. It also means that the glass structure stays in place, which is important for security for external glass panels doors, for instance.
It Breaks Up Into Pointy Shards
If the glass has broken up, though, into variable-sized, pointy pieces, it might be ordinary rather than safety glass. It is of course definitively tricky to judge, with complete accuracy, just by how it breaks. However, a professional in glass repairs will know the exact type positively once they see it.