What impact glass is
Impact glass is laminated glass: two panes bonded to a tough interlayer. When something strikes the glass it may crack, but the interlayer holds the pieces in the frame, so the opening stays closed.
The frame, the anchors and the hardware are part of the system and are tested with the glass.
How it is tested
Impact products are tested by firing a heavy missile, in the large-missile test a 9-pound 2x4 at about 50 feet per second, at the glass, and then cycling air pressure up and down to simulate gusting wind. The product must hold together through both.
Different jurisdictions use test protocols such as ASTM E1886 and E1996 and the Miami-Dade TAS 201, 202 and 203 protocols.
What the approval tells you
A product approval lists the sizes, glass types, frame and anchoring that passed. In Miami-Dade and Broward, the approval is a Notice of Acceptance. Elsewhere, products have a Florida Product Approval number.
The approval is the document the building department checks against the product on the job.
Comfort benefits
Laminated glass also reduces outside noise and blocks most ultraviolet light, and it can be combined with insulated glass and low-E coatings to cut solar heat.
It is a protection product that is also a comfort product.
