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.