Man-made impacts include objects wielded by people intent on breaking the glass to gain entrance inside, explosives placed in or near a building that may result in the glass being blown in or outside (or both) the building, and motor vehicles driven through the glass. If a bomb was detonated in the area, the impact could be significant. According to a research paper from the United Nations Department of Safety and Security, casualties from explosives are most frequently caused by the fragmentation of structural and other material. Studies on several large bombing attacks show that flying glass fragments were responsible for 80 percent of injuries and deaths.
A Cost-Effective Solution
Unprotected glass on a building can be cost-effectively made safer to reduce the dangers resulting from broken glass by retrofitting the building with safety/security window film. Window film works right away even when there is not a threat and is considered a passive system, since it does not require human intervention to be activated. When compared to glass replacement with laminated glass panels, window film may cost significantly less than glass replacement. In addition, since replacement of the glass may increase the weight load on the window framing system, in many cases the entire window must be replaced instead of just the glass itself. Window films may have a long life as well, extending beyond a 20-year range.
Safety and security window film is cost-effective and non-disruptive to install, and may offer a range of additional benefits such as improved thermal comfort, reduced energy use and improved appearance. Based on proven energy savings, window films may also have a fast payback period. Window films block 99 percent of the sun’s harmful UV rays that contribute to fading of furnishings and cause harm to occupants’ skin and eyes in the form of cancers, cataracts and wrinkling. They may also reduce solar heat gain into a building’s interior by as much as 84 percent.
When properly installed, safety and security film forms an almost invisible protective coating or membrane on the interior side of the glass surface. The film may also be attached to the glass with an aggressive pressure sensitive adhesive or also anchored to the frame with an attachment system. When an impact causes the glass to break, the film can stretch and withstand some or all of the energy generated by the stress. The result is much of the broken glass remains within the framing system preventing shards of glass becoming lethal projectiles. When the glass is held in place, it also may take more time for an intruder to gain entry.
According to the International Window Film Association, many quality 8-mil security films installed on annealed glass will pass the same breakage tests as many types of laminated glass, referred to as “human impact” tests. Both the Consumer Product Safety Council and ANSI Z97.1 use a 400 foot-pound test for this. Security films tend to be 4 to 12 mil thick. A mil is one-thousandth of an inch (0.001 inches), so an 8 mil window film is 0.008 inch thick.
Each window film manufacturer extensively tests their products to ascertain individual performance and ensure continued durability There are many existing standards to which products can be tested, however security window films are usually tested to the following standards.
Attack Protection
UL 972 test procedure is sometimes used as one indicator of resistance to intrusion, or breaking through a window with security film installed on it. Although it may indicate an increase in difficulty and delay in an attacker getting past a window or door system, other variables such as impact resistance and degree of edge tear should also be considered.
Impact Protection
ANSI Z97.1, impact testing for any glass with applied security film and the Consumer Product Safety Product Act Regulations under section 1201, or 16CFR CPSC 1201.
Blast Protection
International Standard Blast ISO 16933 and ASTM 1642 blast tests determine the blast mitigation capabilities of the glass with an installed film system.
Warning: Be Wary Of Claims
Sometimes seemingly reputable companies may make claims that are not backed by recognized, industry-standard laboratories or industry-recognized research. For example, a video that shows glass with security film installed claims to block the penetration of high velocity bullets may in fact be dependent on the glass the film is installed on, and not the film itself.
Peace Of Mind
Beefing up building security is a new factor that we have live with so people feel safer in this today’s atmosphere of concern. Safety and security window film installation adds peace of mind for any person wanting to go about their everyday business with less concern about impact from flying glass shards and other dangers.
Darrell Smith is the executive director of the International Window Film Association, a role that he has held for over 25 years, and he represents the interests of the window film industry to the National Fenestration Rating Council, the Glass Association of North America, the Protective Glazing Council International, the Glazing Industry Code Committee, the California Public Utilities Commission and the California Energy Commission, the International Code Committees, and the U.S. Department of Energy and U.S. Environmental Protection Agency.
