Window film
From Wikipedia, the free encyclopedia
Window film, also called window tint, is transparent plastic film or metallic laminate which is applied to glass windows. They are available in many different compositions with varying effects on the optical and mechanical properties of the underlying glass. Because window film is applied to finished glass it is easier to install and less costly than chemically altered specialty glass.
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[edit] Primary properties
Heat rejection films are normally applied to flat glass windows to reduce the amount of infrared radiation entering through the windows. Such films are either dyed or metalized to convert incoming solar radiation to infrared radiation, which is then rejected back through the glass to the exterior. This can result in substantial reductions in cooling costs.[1] Such films also reduce the amount of visible and ultraviolet light entering a window, and are often applied to reduce fading of the contents of a room. Silvered film may also be employed to the same end.
Security films are applied to prevent glass from shattering. Typically applied to commercial glass, these films are made of heavy-gauge plastic and are intended to maintain the integrity of glass when subject to heavy impact. The most robust security films are capable of preventing fragmentation and the production of hazardous glass shards from forces up to and including bomb blasts.[2]
Graphic design films are generally colored vinyl or frosted. Frosted finish films closely resemble sandblasted or acid-etched glass, while vinyl films are available in a wide range of colors. Both types of films are commonly used in commercial applications.
Privacy films reduce visibility through the glass. Privacy film for flat-glass commercial and residential applications may be silvered, offering an unimpeded view from the low-light side but virtually no view from the high-light side. It may also be frosted, rendering the window translucent but not transparent. Privacy films for automobiles are available in gradients of darkness, with the darker tints commonly known as "limo tint".
Films are available with almost any conceivable combination of the above properties.
[edit] Regulations for automotive use
Automobile window tinting, by its nature, reduces the visible light transmittance through a car's windows. This can be problematic at night, when motorists must be able to see through the windows of other vehicles in order to spot hazards which would otherwise be obstructed. Police officers must also be able to identify the passengers in a vehicle.
In many jurisdictions, there are government rules and regulations in place to ensure darkness levels of films do not present a danger to motorists.
In the United States, the federal Department of Transportation specifies a minimum of 70% visible light transmission (VLT) for window tinting on the windshield and the windows to the immediate left and right of the driver. The DoT does not specify any VLT requirements for any other windows [3]. Individual states can pass laws that go further than the requirements set forth by the DoT. The DoT regulates commercial vehicles, not private vehicles. Links to state laws that govern tinting on private vehicles can be found below. Private vehicles may have tint on the windows to the immediate left and right of the driver as dark as 20% VLT, depending on the state.
In Canada, automobile tinting laws are set at the province level.
[edit] Installation
Window films are usually professionally installed; however, most films require few specialized tools to install and may be installed by consumers. Incorrectly installed films may bubble or peel.
[edit] Removal
Window tint and the adhesive that adheres it to the glass is quite difficult to remove. While it is generally best to leave this job to the experts, the consumer can do so with the appropriate materials and care. The process involves heating the film with a hair dryer or a steamer to soften the adhesive, pulling the film off in small sections, and dissolving the glue with a strong ammonia solution which may then be wiped off.
