Safety and security window film
From Wikipedia, the free encyclopedia
Safety and security window films are polyester films that are applied to glass & glazing in order to hold them together if the glass is shattered (similar to laminated glass). The main difference between film and laminated glass is that the film can be applied to the glass or glazing after manufacture or installation, i.e. it is a retrofit product. These films are used widely all over the world, they can be found on trains, buses, cars, and buildings.
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[edit] Structure and physical properties
The films are adhesive coated to bond them to the glass. The better safety films are those which are smooth-coated, as they have far superior optical clarity.
[edit] Certification and testing
Safety and secuirty window films are designed to perform under adverse conditions. As such, standards and standard tests have been devised to ensure that these films will perform in such a situation. It is adviseable for any prospective user to ensure that their supplier can produce certification for such codes and standards. There are four best known organisations that produce standards and guidlines for how a film performs under impact (see table below).
| Organisation | Relevant Standard | Description |
|---|---|---|
| British Standards Institute | BS 6206 (Class A, B & C) | British standard impact testing for annealed glass with applied safety film |
| American National Standards Institute | ANSI Z.97 | American Impact testing for annealed glass with applied safety film |
| European Committee for Standardization | EN12600 | List of EN standards Eurpoean standard Classification of Resistance of Glazing to Impact. |
| CPSC | 16 CFR 1201, Cat II (400 ft-lb) | (American) Impact testing for annealed glass with applied safety film |
| General Services Administration | GSA Conditions 1 through 5 | Standard Test Method for Glazing and Window Systems Subject to Dynamic Overpressure Loadings |
[edit] Applications
Safety and security films are used where there is a potential for injury from broken glass(such as glass doors or overhead glazing). These films can be applied to toughened, annealed or laminated glass. They are available in various thicknesses, from 100micron (or 4mils) through to 375microns + (15mils). The film thickness is selected for level of protection desired and the dimensions of the glass pane. Manufacturers recommend that for glass unto 3mm (approx 1/8th Inch) 100micron (or thicker) film can be used. For glass 6mm+ thickness (approx 1/4inch) a film of at least 175microns is recommended.
These films can be applied for security applications, where a delay of forced entry is desired. The Performance of these films is affected by adhesive bond strength, thickness of the polyester, quality of application and window structure/frame.
The films are adhesive coated to bond them to the glass. The better safety films are those which are smooth-coated, as they have far superior optical clarity.
Safety and security films can have components added, such as for solar control & decorative effects. However, as mentioned before, it is their physical properties that allow them to be used in various applications, such as:
[edit] Protection from spontaneous glass breakage
Toughened glass (tempered) windows can be and often are subject to sudden failure, for no apparent reason.
This is caused by contaminants (such as a nickel sulphide inclusion) embedded in the glass during manufacturing can cause this explosive failure months or years later. Such failure in homes and commercial buildings can cause a sudden opening in the building, exposing its contents to the elements, with wind and rain causing far more damage than the simple cost of replacing a window pane. Protective safety films are an ideal remedy to maintain the weather seal of the building and prevent the massive rain of glass pellets that would otherwise instantly fall from tempered glass breakage.”
[edit] Personal safety
When float glass is broken (normal window glass), it breaks into sharp shards that are dangerous anybody in the vicinity. This is particularly hazardous if the window is broken by human impact. Toughened (tempered) glass can produce showers of small glass pellets that can cause serious injury; especially in the event of a car crash (as most automotive side glass is tempered). The building codes of some countries specify requirements for personal safety in architectural glass and glazing. Certain films, with correct certification can be used to upgrade existing glass and glazing to meet the safety standards specified in the building codes.
[edit] Protection of glazing during earthquakes
In many parts of the world, earthquake activity is an ever-present fact of life. Ground motion during seismic activity causes building movement, which in turn causes glass breakage and glass fall-out, endangering people below, and again exposing a building’s contents to weather damage and theft during looting sprees. Safety and security films have proven their worth in protecting people and property during seismic activity, by helping retain window glass in its frame, thus prevent injury by falling glass
[edit] Increased protection from bomb and blast hazards
Explosions case widespread damage, and in an urban environment (often containing lots of glass) the risk of injury is increased. In the event of an explosion in an urban area, flying glass is often the biggest cause of injury/trauma. However, certain specially designed films, when applied correctly can contain these shards of glass, protecting the internal environment and in some cases retaining the pane of glass in the window frame. People sourcing films for this purpose should choose a product from a manufacturer that can produce results for General Services Administration (GSA) blast ratings, and check with the manufacturer that the installer has sufficient experience & knowledge to offer such products.
[edit] Additional protection from hurricanes and windborne debris
Safety films can be used as an additional protection against flying glass when glazing is broken by windborne debris. By helping to prevent windows from shattering, or retaining shattered glazing in its frame, these films help maintain the “weather seal” of a building. This helps reduce damage from water and high winds. If the seal can be maintained, Roofs are less likely to be blown off, and it is more likely a building can be saved.
