Window film

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There are many types of window tint available in the market for a wide variety of uses from solar heat reduction to UV protection, privacy to safety and security, decorative applications to heat retention.

Contents

Primary properties

The colorful film on these windows gives the building a unique appearance while providing privacy and insulation from the sun.

Heat rejection films are normally applied to the interior of flat glass windows to reduce the amount of infrared, visible light, and ultraviolet (UV) radiation entering windows. Such films are usually dyed or metalized (which can be transparent to visible light) to convert incoming solar radiation to infrared radiation, which is then rejected back through the glass to the exterior."[1] Modern window film technology has created Ceramic Window Film which are non-metallic and do not contain dyes that can result in discoloration. The ceramic and metallic window films usually cost 10–15 percent more than regular window film but can reduce energy transmission by as much as 80 percent."[2] Ceramic window films cost slightly more but provide a substantial increase in blocking UV rays and ability to control heat transfer.

To keep the sun's heat out of the house, a low-emissivity coating should be applied to the outside pane of glazed windows. If the windows are designed to provide heat energy in the winter and keep heat inside the house (typical of cold climates), the low-emissivity coating should be applied to the inside pane of glazed windows. Such films also reduce the amount of visible and ultraviolet radiation 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. Spectrally selective films act by blocking certain wavelengths of the sun's infrared radiation and reject heat without reducing natural light.

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 such as bomb blasts. Some companies have even experimented with bullet ballistics of multiple layers of security film.[3] Another key application for security window films (safety window films)is on large areas of "flat glass" such as storefront windows, sliding glass doors, and larger windows that are prone to hurricane damage. These security films, if applied properly, can also provide protection for vehicles.[4] These security films are often tinted and can be up to 400 micrometers (µm) thick, compared to less than 50 µm for ordinary tint films. If anchored correctly, they can also provide protection for architectural glazing in the event of an explosion.[4] A layer of film (of 100 µm thickness or greater) can prevent the ejection of spall when a projectile impacts on its surface, creating small dagger-like shards of glass that can cause injury.

Switchable films can be switched from opaque to clear by a safe voltage under 36V AC. In its opaque state, it can be perfectly used as a projection screen that is viewable from both sides. 3G switchable film also has UV (100%) and IR (94%) blocking functions and security function.

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 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."

Correctly-applied mirror film can create one-way mirrors.

Other benefits include protection for passengers in the rear, protection from UV rays (which have some harmful effects), cooling for pets, greater privacy, reduced chance of theft (because valuables are less visible), reduced glare and reflection on liquid crystal display (LCD) screens, and protection for those who have conditions involving photosensitivity or skin sensitivity, such as lupus (SLE). Window film is also considered more effective and practical than stick-on blinds.

Selection of window film

Not all films are suitable for all glass. You must consider the absorptance of the glass and the film, the size of the pane, the thickness of the glass, the construction of the window – is it single pane, insulated glass, treated (with a low-emissivity coating), laminated or toughened.

Advice on the appropriate selection of film for the glass is vital to ensure that the glass does not crack as a result of thermal stress. However, it is possible that a pane of glass may break subsequent to the application of an appropriate film, because the pane has been damaged during the glazing of the window, or as a result of movement of the building or other physical stresses that are not apparent at the time of the application of the film.

Glass may crack subsequent to the application of sign writing or if heavy, thermally efficient drapes are hung close to the glass, particularly if the edges of the glass are damaged.

The chances of glass breakage occurring subsequent to the application of film or sign writing or the hanging of drapes, are very small. However breakage can occur and it is impossible to predict the edge condition of the glass without removing it from the frame – an approach that is not practical.

Unintended features

Under certain conditions, window film will exhibit iridescence. This phenomenon usually occurs at night, when the source of illumination within a building is fluorescent lighting.

The amount of iridescence may vary from almost imperceptible to very visible. It most frequently occurs when the film is constructed with scratch resistance protection.

When iridescence does occur in window film, the best way to stop it is to prevent the fluorescent light from illuminating the film or to use an alternative type of light.

Certification and standards

The thicker window films known as safety and security window film are designed to perform under extreme conditions, and as such there are specific standard criteria these films should meet, such as American standards ANSI Z.97, CPSC 16 CFR 1201, Cat II (400 ft-lb), and the British Standards BS 6206 (Class A, B, C). The European Committee for Standardization offer the EN12600 standard Classification of Resistance of Glazing to Impact. Often, building codes dictate that a film must have a report verifying that it has met at least one of these standards.

Solar window film is usually subject to less critical testing. However, standards are in place to maintain a level of quality in the industry. The ANSI Standards ASTM E903 and ASTM D1044-93 relate to the solar/UV transmission properties and abrasion resistance, respectively. The larger window film manufacturers use these standards to guarantee the quality of their raw materials and finished products.

Regulations for automotive use

Window tint on a convertible in America. Tint on the front window is lighter than on the back window because of window tint laws.
Photo of vehicle with illegal window tint being measured at 2% light transmittance.

Automobile window tinting reduces the visible light transmission (VLT) through car 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 also may want to be able to identify the passengers in a vehicle.

In many jurisdictions, there are laws to ensure darkness of films do not present a danger to motorists:

U.S.

Tint Limits by U.S. state (when measured on the front side window)[5]:

StateVLTStateVLTStateVLT
Alabama32%Louisiana40% State LawOhio50%
Alaska70%Maine35%Oklahoma25%
Arizona30% to 36%***Maryland35%Oregon35% State Law
Arkansas25%Massachusetts35%Pennsylvania70%
California70%Michigan70% State LawRhode Island70%
Colorado27%Minnesota50%South Carolina27%
Connecticut35%Mississippi28%South Dakota35%
Delaware70%Missouri35%Tennessee35%
Florida28%Montana24%Texas25% state law
Georgia32%Nebraska35%Utah43%
Hawaii35%Nevada35%Vermont70%
Idaho35%New Hampshire70%Virginia35%
Illinois35%New Jersey70%Washington24%[6]
Indiana30% state lawNew Mexico20%West Virginia35%
Iowa70%New York75%Wisconsin50%
Kansas35%North Carolina35%Wyoming28%
Kentucky35%North Dakota50%District of Columbia70%

Current as of 17 July 2010

(Lower number is less light transmittance, thus darker tint)

Full details of other glazing and sticker rules can be found at the Federal Motor Carrier Safety Administration page[7]

It is quite common for states to provide more stringent regulations on tinting front windows as opposed to those located in the rear of the vehicle.

In other countries

Installation

Whether you choose to do it yourself or you let an experienced window tinter do it, make sure that the person doing the tinting is prepared to be accurate. The smallest mistake can lead to unsightly gaps, creases and bubbles. Whoever works on your vehicle should also know the law regarding the darkest legal window film for the procedure.

Removal


Removing window tint film bears several methods for doing so:


This is the easiest and cleanest method for removing window tinting. Heat is applied to the inside of the window using a hand held steamer or a blow dryer. This is done to melt the glue that holds the tinting sheet in place. As the glue melts, you can gently pull the sheet to remove it. This method must be carried out very slowly because pulling the sheet too hard can cause it to break and will result in glue being left on the window.

This method involves cutting and lifting the tinting sheet using a razor blade. Once the tinting sheet is peeled off, the glue that remains on the window can be scrubbed off with soapy water. Extra care should be taken with this method because it’s possible to scratch the windows or damage the back window defroster lines.

This method requires some preparation. You will need to park your car in a sunny area and you will also need to cover the interior of the car with a plastic tarp or garbage bags to protect the upholstery. In this method, you spray the inside of the window with undiluted ammonia and then you cover it with a plastic bag; the bag should sit smoothly and evenly against the window. You then spray the outside of the window with soapy water and cover it with a plastic bag as well. You let the car sit out in the sun for a while and then lift one edge of the window tinting using a razor blade or your fingernail. The tinting sheet should come off cleanly in large pieces. You can then gently scrub the window and wipe it dry.


Although effective, this is the messiest method and it may pose a health risk due to the fumes that are produced. As previously mentioned, always keep a window open as you work to avoid inhaling toxic fumes

Non-automotive uses

Window tint can be applied to any object made of glass. Many window tint companies will tint shopfronts windows, office block windows and house windows. Some will even tint objects such as mirrors and coffee tables giving unique looks to everyday objects.

Homes can be tinted to save energy, fight heat, and increase privacy. Decorative films are offered in many styles and shades that can dress up a space such as an office waiting room, bathrooms, and more.

See also

References

  1. ^ [1]." Solar energy. What it is and how it affects glass fronted rooms.
  2. ^ Your Home: Low-emissivity Window Glazing or Glass." A Consumer's Guide to Energy Efficiency and Renewable Energy. United States Department of Energy Energy Efficiency and Renewable Energy.
  3. ^ "Safe Rooms Within Schools." Federal Emergency Management Agency, United States Department of Homeland Security.
  4. ^ a b "Safety/Security Film." International Window Film Association.
  5. ^ U.S. State Tint Limits. International Window Film Association. 28 April 2003.
  6. ^ RCW 46.37.430 Safety glazing - Sunscreening or coloring (see 5d & e for exceptions). Washington State Legislature. Revised January 4, 2012. Accessed April 21, 2012.
  7. ^ [2]
  8. ^ "Canadian Window Tinting Rules & Laws." International Window Film Association. 28 April 2003.
  9. ^ "Tinted Windows: Your Questions Answered" (PDF). Vehicle and Operator Services Agency. October 2005.
  10. ^ Rohrer, Finlo. "Tinted windows to the soul." 31 May 2007 BBC News Magazine.
  11. ^ Правовые основы тонирования
  12. ^ Тонировку стекол разрешают только «ограниченному кругу лиц» 2 February 2006
  13. ^ rta.nsw.gov.au Vehicle Standards Information - Windscreens and window tinting
  14. ^ 27. For the reasons afore-stated, we prohibit the use of black films of any VLT percentage or any other material upon the safety glasses, windscreens (front and rear) and side glasses of all vehicles throughout the country. The Home Secretary, Director General/Commissioner of Police of the respective States/Center shall ensure compliance with this direction. The directions contained in this judgment shall become operative and enforceable with effect from 4th May, 2012.