Float glass
Float glass or the so called single glass or annealed glass is since 1952 the international standard for the production of high quality glass made of ;
When broken the break pattern consists of big glass shards |
Half-tempered glass
Half-tempered glass, or also called heat strengthened glass, is the result of a thermal treatment where, compared to tempered glass, the cooling down is slower. Half-tempered glass is 3 times stronger on impact compared to float glass. When broken the break pattern consists of big glass shards |
Tempered glass
Tempered glass is the result of a thermal treatment where glass is heated more than 600°. The glass then undergoes a high-pressure cooling procedure called "quenching". During this process, which lasts just seconds, high-pressure air blasts the surface of the glass from an array of nozzles in varying positions. Quenching cools the outer surface of the glass much more quickly than the center. As the center of the glass cools, it tries to pull back from the outer surfaces. As a result, the center remains in tension, and the outer surfaces go into compression, which gives tempered glass its strength. Tempered glass is 5 times stronger, in impact tests than float glass. When broken the break pattern consits of small, relatively harmless pieces. |
The disadvantage of tempered glass is mostly the quality of finishing, like you can see underneath.
Comparing to float glass the polishing of tempered glass happens before the lamination, during the lamination process it may happen that a slightly movement of one of the glass panels occurs. When this happens you get one glass panel higher than the other one and when poor quality of lamination the PVB's look like a mess.
Float glass is firstly laminated and then cut and polished, that's why the edges are always of a high finishing quality.
Within the three types of glass explained above, we can dissociate clear glass & extra clear (white) glass
The standard clear glass has an important quantity of iron oxide which is to be found in the sand, one of the raw materials which glass consists of, and which gives the glass a rather light green shine. |
By adding other substances during the melting of the standard clear glass and by using an higher melting temperature the iron oxide is been extracted. By doing this we become an extra clear glass ( extra white) with a much higher light transparency en much more energy transmittance of sun in the winter for instance. Light is Warmth |