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11/3/2008 12:00:00 AM
Compiled by FaciliesNet Staff
Not all window films are created equal. Window security film is very different from solar window film. Though some security film will block solar radiation, the primary purpose of window security film is to prevent shards of flying glass from injuring occupants if the window breaks.
Causes of breakage can include bomb blasts, hurricanes, seismic events, or people attempting forced entry through a window. Security window film encapsulates the glass, so the glass doesn’t shatter into small pieces that go flying.
At 4 to 14 mil, security film is significantly thicker than solar control film, which is generally 1.5 to 2 mil thick. While solar control film is applied only to the part of the window that is visible, security film is installed into the window system itself by a process known as anchoring.
Two types of anchoring are available, known as wet-glazed and mechanical installations. A wet-glazed installation involves removing the rubber around the window from the gasket and replacing it with a structural silicon sealant that fills the space between the window and the frame. A mechanical attachment involves overlapping the film around the edges of the window and securing the film with bolts to an internal frame. Both methods are meant to ensure that the film will hold glass fragments together and to prevent flying glass.
Installing an attachment system with the window film increases the performance. Basically, the attachment system fixes the filmed glass to the window frame. The goal is to prevent the entire window unit from becoming dislodged and sent into a building’s interior in the event of a storm or blast.
“Attachment systems utilize either a mechanical system or a chemical sealant system to ‘attach’ the window film, after installation, to the window framing system,” says Darrell Smith, executive director of the International Window Film Association (IWFA). “This gives a higher level of protection by holding the sheet of film with the attached glass fragments in place longer than would be achievable by merely covering the daylight portion of the glass with film.”
For best results, experts suggest discussing attachment systems with the manufacturer of the window film being considered.
Shattered glass can be a risk to buildings that may not necessarily be a target for a bomb blast, but are in the vicinity of a building that is. In other words, if a threat assessment shows that there are high-profile targets nearby, applying security film to the windows might make sense to protect against residual blast effects.
The value of security film in protecting building occupants has been recognized by the federal government, especially after the events of 9/11, says Daniel Leclair, a security consultant with SAKO Associates.
“All government buildings have some type of window film or protective glazing on the windows,” Leclair says. “The majority of federal buildings have wet-glazed film application as a requirement.”
Security film is also a recognized benefit in hurricane-prone areas like Florida because of the round the clock protection it provides. The Protecting People First Foundation studied the performance of window film during last year’s devastating hurricanes in Florida. The effort, called Project Safe Windows, led to a report titled Finding the Breaking Point. In one high-rise condominium, some windows were protected by 8 and 12 mil security window film; other windows had no film. None of the windows that had film were damaged, while some unprotected windows did sustain damage.
The report also described a pharmacy located in a strip mall. Although many storefront windows in the area were damaged, the pharmacy’s windows, protected by window film, were not damaged. In fact, they kept a looter from breaking in three days after the hurricane hit.
One final piece of advice: Ask to see — before signing the contract — the manufacturer’s warranty. Most warranties are for a five- to 10-year period. Check not only the length of the warranty, but also whether it covers removal of any failed product, as well as reinstallation of the replacement product.
Window Films Can Bring Security, Energy Gains