Forcible Entry Demonstrations
Page A-1
Air-blast Resistant Window Systems
Appendix A Terminology
APPENDIX A TERMINOLOGY
Annealed Glass (AG)
Annealed glass, often referred to as float glass or plate glass, is the most common glass
type and is manufactured by pouring molten glass onto a bed of molten tin, the glass
solidifies before the tin and is subsequently fed into an annealing lehr where it is slowly
cooled to minimize residual stresses.
Annealed glass has a minimum amount of residual surface compression. Because of this,
when failure occurs annealed glass typically shatters in large hazardous shards. [2].
Annealed glass is the weakest of the three glass types discussed in this report.
Attached Film Application
Retrofit application of security film that extends beyond the glass and is
fastened to the window frame with either a mechanical attachment device
(steel or aluminum batten ), adhesive tapes, or silicone sealant. At this time,
mechanically attached security film is the most common configuration in
Film
use. Generally, attached film will give better protection than daylight film,
if the mullions, frame, and wall are able to withstand the additional loads.
Film can be attached on one side (the top), two-sides (either the two vertical
Attachment
or the two horizontal sides), or on all four-sides. The more sides attached to
the supporting structure, the more protection provided by the properly
designed retrofit.
Bite
Mechanically
A window bite is the portion of the window framing system which holds the
Attached Film
glass in place. Typical window bites vary from " to " and are dry
glazed. Window bites for air-blast resistant windows be either wet glazed or
dry glazed and begin at 3/8" if wet glazed and can go up to greater than 1".
Blast Curtain
Blast curtains, with specially designed fabric and installation methods, self-deploy to
catch flying glass and other debris before it projects into the room. Blast curtains are
usually used in conjunction with a daylight film application.
A curtain made of a mesh of high-strength synthetic fibers that is affixed behind a
monolithic or daylight-film-retrofitted window to catch glass fragments in the
event of an air-blast.
Clearing
Removal of enough glass/film/laminated material from the window frame to
allow safe and effective operations through the remaining opening.
Daylight Film Application
Film
m
Security film which is installed on the vision portion (glass only) of the window
system without attachment to the mullions or frames. Hazard to occupants is
reduced with this application method, even if the glass/film combination comes
Daylight Film
Application
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