STRUCTURAL GLASS FACADES - USC School of Architecture

laminated panel comprised of a tempered back ply to provide optimum strength with an
annealed outer ply to reduce distortion in the reflected images.
Most laminated glass is simply comprised of the laminating material between two glass
sheets; a 2-ply panel. Multi-ply laminates have become common over the past two decades,
however, in structural glass applications, and security applications as mentioned previously.
Glass stair treads and landings are typically comprised of three or more ply. Beam and
column elements integrated into the design of structural glass facades, as well as other
forms of all-glass structures, are sometimes comprised of multiple-ply laminations.
Some interlayer materials maintain translucency after laminating, producing an effect similar
to sandblasted glass without the problem of keeping it clean (the sandblasted surface picks
up smudges and fingerprints very easily). The laminate material can provide a decorative
effect also. A range of tinted and patterned laminates have become available, with more
choices appearing on a daily basis as the industry competes for the attention of designers.
Other laminating materials are available with properties that improve thermal performance,
fire safety and security.
As discussed earlier, the weather seal in most structural glass facades, and all point-fixed
glass systems, is provided by a field-applied wet silicone joint between adjacent panes of
glass, with the silicone adhering to the glass pane edges. With laminated glass the silicone
material will be in contact with the exposed laminate at the glass pane edges. (fig) Problems
can result if the interlayer is not compatible with silicone. Some laminated glass installations
as described here have experienced a clouding of the interlayer emanating from the edge of
the glass and spreading inward as much as approximately 1 inch (25mm). (A similar problem
can occur with laminated panels whose edges are left exposed to the elements.)
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