Float Glass is produced by floating molten glass over a bed of molten tin on continuous basis.  In the process, the tin is progressively cooler as the glass ribbon flows down stream.  The glass is cooled sufficiently at the end of the bed so that it can be raised onto rollers without marring the surface or producing waves in the glass.  As it leaves the bed of metal, the ribbon of glass is carried on rollers through a controlled cooling oven or annealing lehr, thus relieving strain that would be produced by rapid cooling.

Fully tempered Glass is produced by uniformly heating the annealed, i.e. untreated glass to a temperature approaching its softening point, followed by rapid air-cooling.  This process results in glass with compression layers at the surfaces and edges and the glass core is in tension.

This glass has approximately four times the resistance of annealed glass to uniform loading, thermal stresses and most impact loads.  After tempering, this glass cannot be cut, have its edges ground, be drilled or other alteration.  When fractured, it breaks into a fail-safe pattern of small relatively harmless particles so it is considered as a safety glass.

Laminated Glass laminated glass consists of two or more plies of glass bonded under temperature and pressure to interlayers of polyvinyl butyral plastic. The glass surfaces bonded to the plastic cannot be patterned or otherwise irregular.  Heat-absorbing, heat-reflecting, fully tempered, heat-strengthened and wired glasses may be laminated in combination with other types.  Laminated glass when impacted and broken tends to remain intact due to the bonding of the glass to the plastic interlayer.  It is considered as a safety glass as well.
 

Broken Laminated Glass

Heat-Strengthened Glass is produced in approximately the same procedures as fully tempered glass.  However, it has only a partial heat temper producing approximately twice the strength of annealed glass.   When it fails, it breaks into fragments much larger than those of fully tempered glass as it is not considered a safety glass.
 

Broken  Heat-Strengthened Glass	Broken fragments of heat-Strengthened Glass