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3M
Films : Scotchshield™ :
Attachment Systems
Security films have traditionally
been installed using a technique
known as a daylight application.
The film is applied to the window
and bonded to the glass when
the pressure sensitive adhesive
is activated by a mild solution
of dishwashing detergent and
water. Excess film is then trimmed
to fit against the window's
gaskets to create a finished
product.
After the tragedy of Oklahoma
City in 1995, consideration
was given to the fact that the
entire glass pane could be blown
out of the frame given a severe
explosion. Film manufacturers
responded to this additional
threat by developing anchoring
systems. Two types have been
developed - a mechanical batten
system, and a wet glaze system.
During a mechanical batten system
installation, the film is applied
to the glass in a fashion similar
to that of a daylight application.
But rather than being trimmed
to fit flush against the gaskets,
the film overlaps the window
frame on one, two, or four sides
and is then clamped to the frame
at a 90° angle using a system
of metal bars and screws. This
90° angle inherently weakens
the film and the system of metal
bars and screws alter the window's
appearance. Additionally, this
type of installation is time-consuming
and very expensive.
A less expensive and more effective
installation technique is a
wet glaze system. Wet glaze
attachment systems use a high
strength silicone adhesive to
anchor the film, glass, and
window frame to each other.
The film is applied to the glass
in a fashion similar to that
of a daylight application except
that the gaskets are removed
and the film's edges are inserted
behind the window frame. A bead
of silicone is then applied
flush against the frame to overlap
the film and take the place
of the original gaskets. 3M
developed its own wet glaze
system, the Ultraflex Window
System, which uses a Dow Corning
995® silicone structural
adhesive. This method is less
costly than a mechanical batten
system and is approved for Washington,
DC historical buildings.
During a test conducted for
3M by Applied
Research Associates, a third-party
testing firm, results showed
that 3M films
achieved higher levels of protection
when anchored to the window
frame by Ultraflex than by a
mechanical batten system. |
