Addison Glass & Mirror






Safety Glass:

Laminated - A process by which two or more lites of glass are sandwiched about a polyvinyl layer to give the glass strength against penetration.  It is not shatter proof or unbreakable.  The most common application that everyone should be familiar with is automobile windshields. 

Tempered - The process of heat-treating glass, to provide much stronger characteristics than annealed, or un-tempered glass.  Once again, tempered glass is not shatter proof or unbreakable.  It is designed to break into very small pieces to help alleviate severe lacerations.  This process is used on automobile side and rear windows as well as storefronts and doors that are required by local building codes.

Table:
Uniform load strength - Heat-Strengthened Glass
Note: Data obtained from Fed. Spec. DD-G-1403.
The values have not been verified

Nominal Glass Thickness. mm (in) Average Breaking Pressure times Glass Area.
Pa x m2 (lbf x ft2). Minimum value
3 (1/8) 5895 (1,325)
5 (3/16) 14,800 (3,325)
6 (1/4) 24,000 (5,400)
8 (5/16) 32,700 (7,350)
10 (3/8) 55,000 (12,000)
12 (1/2) 70,000 (16,000)