Window film (tint) is a thin laminate film that can be installed to the interior or exterior of glass surfaces in automobiles and boats and also to the interior or exterior of glass in homes and buildings. It is usually made from
polyethylene terephthalate (PET), a thermoplastic polymer resin of the
polyester family, due to its clarity, tensile strength, dimensional stability, and ability to accept a variety of surface-applied or embedded treatments.
Window films are generically categorised by their construction components (dyed, pigmented, metallized, ceramic or nano), by their intended use (automotive, marine or architectural), by substrate type (glass or
polycarbonate), and/or by their technical performance (privacy, solar control, safety and security).
Window film is normally installed by professional service companies but there are also DIY kits widely available.
The International Window Film Association, founded in 1991, provides unbranded information about window films.
Uses
There are many different grades, shades, colours, and thicknesses of available window films built to offer solutions to a variety of challenges. Window films are a retrofit upgrade for existing glass that can be used to address problems inherent to glazing, including:
* heat and glare reduction
* thermal insulation
* UV filtration
* safety and security
* privacy
* decoration, signage and branding
* protection from
graffiti
Graffiti (plural; singular ''graffiti'' or ''graffito'', the latter rarely used except in archeology) is art that is written, painted or drawn on a wall or other surface, usually without permission and within public view. Graffiti ranges from s ...
.
*Automotive styling
Window films are an extremely cost-effective method to reduce heating and cooling costs in existing buildings by reducing the amount of heat transfer through glazing.
Primary properties
![CIT Building Herndon Va](https://upload.wikimedia.org/wikipedia/commons/5/57/CIT_Building_Herndon_Va.jpg)
Heat rejection films are normally applied to the interior of flat glass windows to reduce the amount of
infrared
Infrared (IR), sometimes called infrared light, is electromagnetic radiation (EMR) with wavelengths longer than those of visible light. It is therefore invisible to the human eye. IR is generally understood to encompass wavelengths from around ...
,
visible light
Light or visible light is electromagnetic radiation that can be perceived by the human eye. Visible light is usually defined as having wavelengths in the range of 400–700 nanometres (nm), corresponding to frequencies of 750–420 te ...
, and
ultraviolet
Ultraviolet (UV) is a form of electromagnetic radiation with wavelength from 10 nm (with a corresponding frequency around 30 PHz) to 400 nm (750 THz), shorter than that of visible light, but longer than X-rays. UV radiation ...
(UV)
radiation entering windows. Such films are usually dyed or metalized (which can be transparent to visible light) to convert incoming
solar radiation
Solar irradiance is the power per unit area (surface power density) received from the Sun in the form of electromagnetic radiation in the wavelength range of the measuring instrument.
Solar irradiance is measured in watts per square metre ( ...
to infrared radiation, which is then rejected back through the glass to the exterior. Modern window film technology has created ceramic window films which are non-metallic and do not contain dyes that can result in discoloration. The ceramic and metallic window films usually cost 50-100+ percent more than regular window film but can reduce energy transmission by as much as 80 percent.
[Your Home: Low-emissivity Window Glazing or Glass](_blank)
''A Consumer's Guide to Energy Efficiency and Renewable Energy''. United States Department of Energy Energy Efficiency and Renewable Energy. Ceramic window films cost slightly more but provide a substantial increase by reflecting and absorbing Infrared radiation (radiant heat).
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 glass so when the glass is broken it holds together, preventing dangerous shards from flying about, or to make it more difficult for an intruder to gain entry. 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
Impact may refer to:
* Impact (mechanics), a high force or shock (mechanics) over a short time period
* Impact, Texas, a town in Taylor County, Texas, US
Science and technology
* Impact crater, a meteor crater caused by an impact event
* Impac ...
. 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 and multiple layers of security film.
[Safe Rooms Within Schools]
" Federal Emergency Management Agency, United States Department of Homeland Security. 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. These security films are often tinted and can be up to 400
micrometers
The micrometre ( international spelling as used by the International Bureau of Weights and Measures; SI symbol: μm) or micrometer (American spelling), also commonly known as a micron, is a unit of length in the International System of Unit ...
(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. A layer of film (of 100 µm thickness or greater) can prevent the ejection of
spall
Spall are fragments of a material that are broken off a larger solid body. It can be produced by a variety of mechanisms, including as a result of projectile impact, corrosion, weathering, cavitation, or excessive rolling pressure (as in a ba ...
when a projectile impacts on its surface, which otherwise creates 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
Sandblasting, sometimes known as abrasive blasting, is the operation of forcibly propelling a stream of abrasive material against a surface under high pressure to smooth a rough surface, roughen a smooth surface, shape a surface or remove su ...
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
In the field of optics, transparency (also called pellucidity or diaphaneity) is the physical property of allowing light to pass through the material without appreciable scattering of light. On a macroscopic scale (one in which the dimensions ...
but not transparent. Privacy films for automobiles are available in
gradient
In vector calculus, the gradient of a scalar-valued differentiable function of several variables is the vector field (or vector-valued function) \nabla f whose value at a point p is the "direction and rate of fastest increase". If the gr ...
s of darkness, with the darker tints commonly known as "limo tint."
Correctly applied mirror film can create
one-way mirror
A one-way mirror, also called two-way mirror (or one-way glass, half-silvered mirror, and semi-transparent mirror), is a reciprocal mirror that appears reflective on one side and transparent at the other. The perception of one-way transmission i ...
s. Note that in order to be effective the light differential must be from 6 to 10 times greater to maintain the intended performance. For example, the buildings in a city, during the daytime are difficult to see into, at night however, they can be seen in with ease and if a light is on in the interior space it is easily seen along with the contents.
Other benefits include protection for passengers in the rear of automobiles, 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 Reflection or reflexion may refer to:
Science and technology
* Reflection (physics), a common wave phenomenon
** Specular reflection, reflection from a smooth surface
*** Mirror image, a reflection in a mirror or in water
** Signal reflection, in ...
on
liquid crystal display (LCD) screens, and protection for those who have conditions involving
photosensitivity Photosensitivity is the amount to which an object reacts upon receiving photons, especially visible light. In medicine, the term is principally used for abnormal reactions of the skin, and two types are distinguished, photoallergy and phototoxicit ...
or skin sensitivity, such as
lupus (SLE). Window film is also considered more effective and practical than stick-on blinds.
UV filtering to reduce fading
Protection from UV light can be accomplished by film that addresses only the UV spectrum. As UV is one of the main sources of fading, it can prolong the life of fixtures and fittings. Basic colorless clear films reject (absorbs) some UV radiation up to 380 nm, and depending on the manufacturer, UV inhibitors are added to the polyester, with specialist films offering protection to 400 nm. Tinted films are necessary for protection to 500 nm.
Window films filter out over 99% of UV rays to 380 nm, reducing the main factor in fading. However, additional factors such as solar heat, visible light, humidity, and presence or absence of chemical vapors also contribute to fading. Therefore, the greatest protection from fading is offered by tinted or metallised window films that reject large levels of heat and visible light, in addition to UV.
Selection of window film
Not all films are suitable for all glass. The absorptance of the glass and the film, the size of the pane, the thickness of the glass, the construction of the window should be considered in terms of 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.
Thermal properties
Heating and cooling systems have energy costs, and window films can be used to increase
building insulation.
Modern windows with
low-solar-gain glass do not need retrofit films, but since most of the existing windows do not have a low
solar heat gain
Solar gain (also known as solar heat gain or passive solar gain) is the increase in thermal energy of a space, object or structure as it absorbs incident solar radiation. The amount of solar gain a space experiences is a function of the total in ...
, window films make a lot of sense as a retrofit energy improvement. They can provide thermal comfort and are one of the most cost-competitive and environmentally-friendly energy improvements, especially in hot and mixed climates.
Unintended features
Under certain conditions, window film will exhibit
iridescence also known as thin film Interference (TFI) and is well known in the aviation industry. TFI essentially refers to colours gradually changing as the angle of view or the angle of illumination changes. 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.
Building use
Window tints can be used in applications like shopfront windows, office block windows, and house windows. This is often done to increase privacy, and decrease heating and cooling costs. Window tints are used in some
energy efficient buildings
Green building (also known as green construction or sustainable building) refers to both a structure and the application of processes that are environmentally responsible and resource-efficient throughout a building's life-cycle: from planni ...
.
Window films are also used to apply
see-through graphics to glass and other transparent surfaces, to provide advertising, branding, signage and decoration. See-through graphics are most commonly applied using a perforated window film with a graphic visible from one side but not the other side, which remains see-though.
Vehicle wraps on buses are perhaps the widest application of see-through graphics.
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
The American National Standards Institute (ANSI ) is a private non-profit organization that oversees the development of voluntary consensus standards for products, services, processes, systems, and personnel in the United States. The organi ...
Z.97,
CPSC 16 CFR 1201, Cat II (400 ft-lb), and the
British Standards
British Standards (BS) are the standards produced by the BSI Group which is incorporated under a royal charter and which is formally designated as the national standards body (NSB) for the UK. The BSI Group produces British Standards under the a ...
BS 6206 (Class A, B, C). The
European Committee for Standardization
The European Committee for Standardization (CEN, french: Comité Européen de Normalisation) is a public standards organization whose mission is to foster the economy of the European Single Market and the wider European continent in global t ...
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 car](https://upload.wikimedia.org/wikipedia/commons/d/d7/Window_tint_car.jpg)
Automobile window tinting reduces the "visible light transmission" (VLT) through car windows. This can be problematic at night, or when
motorists
Driving is the controlled operation and movement of a vehicle, including cars, motorcycles, trucks, buses, and bicycles. Permission to drive on public highways is granted based on a set of conditions being met and drivers are required to fol ...
must be able to see through the windows of other vehicles in order to spot hazards. Police also may want to be able to identify the passengers or any potential threat inside a vehicle. Therefore, in many
jurisdiction
Jurisdiction (from Latin 'law' + 'declaration') is the legal term for the legal authority granted to a legal entity to enact justice. In federations like the United States, areas of jurisdiction apply to local, state, and federal levels.
J ...
s, there are laws to restrict the darkness of tinting.
Factory tint
"
Factory tint", done at the time of manufacture is generally not an applied film, but instead is done by dyeing the inside of the glass with a darkened pigment during glass manufacturing, an electrical process known as "deep dipping." The pigment gives the glass a tint, but doesn't provide UV ray protection or heat rejection like most window films do. The average VLT of factory tint is between 15 and 26%.
Regulation by country
* Australia— In
New South Wales
)
, nickname =
, image_map = New South Wales in Australia.svg
, map_caption = Location of New South Wales in AustraliaCoordinates:
, subdivision_type = Country
, subdivision_name = Australia
, established_title = Before federation
, es ...
,
Transport for NSW
Transport for NSW, sometimes abbreviated to TfNSW, and pronounced as Transport for New South Wales, is an agency of the New South Wales Government established on 1 November 2011, and is the leading transport and roads agency in New South Wales, ...
permits VLT of 35% on windows other than the windscreen. Tint on the windscreen – a band across the top is permitted with a depth of no more than 10% of the depth of the windscreen. An exception to the side and rear window tinting regulations applies to cars tinted before 1 August 1994.
* Belarus— Any kind of window tint is illegal. An exception is made for factory tint in vehicles purchased before 1 April 2006. Also exempt are vehicles of cash collectors, KGB and certain officials.
* Canada— Automobile tinting laws are set at the
provincial level
Provincial may refer to:
Government & Administration
* Provincial capitals, an administrative sub-national capital of a country
* Provincial city (disambiguation)
* Provincial minister (disambiguation)
* Provincial Secretary, a position in Can ...
.
* India— The rules governing tinted glass are defined in
The Motor Vehicles Act 1988, which states that the front and rear windshield should be 70% VLT and all other windows are limited at 50% VLT. On 27 April 2012, the
Supreme Court of India ordered all black films to be removed.
*Iran- In November 2021, it was legalized by Court of Iranian Administrative justice
* Italy— Window tinting is permitted on rear windows and rear windshield only, with no limits on films graduation. A professional installer certificate is also required, and it's necessary to keep visible the film's brand and homologation number on the windows.
* Lebanon— The Lebanese traffic law does not permit private vehicle owners to tint their front windows (driver window, front passenger window and windshield) without a window film license acquired by the Lebanese defence ministry, nevertheless, it is permitted to tint rear windows up to 0% as no limits are cited. If a private vehicle owner is caught without a window film license, charges will depend on the situation he/she was caught in (100000LBP fine if caught by the
Internal Security Forces
The Internal Security Forces Directorate ( ar, المديرية العامة لقوى الأمن الداخلي, al-Mudiriyya al-'aamma li-Qiwa al-Amn al-Dakhili; french: Forces de Sécurité Intérieure; abbreviated ISF) is the national polic ...
).
* Malaysia— According to Malaysia's current Transport Minister Anthony Loke motorists can now tint their rear windshields and passenger windows as dark as they want. Start from 8 May 2019 permissible VLT levels are 70% for the front windscreen, 50% for front side windows and 0% for rear side windows and rear windscreen.
* Malta— The Malta Transport Authority Permits VLT of 70% on Front Side windows. Tint on the windscreen – a band across the top is permitted with a depth of no more than 100mm of the depth of the windscreen. 30% on the rear and side windows.
* New Zealand— The
NZ Transport Agency
Waka Kotahi NZ Transport Agency (commonly known as Waka Kotahi, and abbreviated as NZTA) is a New Zealand Crown entity tasked with promoting safe and functional transport by land, including the responsibility for driver and vehicle licensing, an ...
stipulates that private motor vehicles must have at least 35% VLT after film has been applied. Side and rear windows; including the windows next to the driver; are allowed full coverage. The front windshield may have an anti-glare band no lower than the extended sun visors. There is no concise regulation for a sunroof. There is an exception for factory tinted glass, which may be any VLT level. Also, commercial goods vehicles are allowed any level of VLT on windows behind the driver, provided the driver has adequate rear vision via side mirrors.
* Russia— Window tinting limits are specified in GOST 5727-88. The limit is 75% for the front windshield (a darker stripe no wider than 10 cm is allowed at the very top) and 70% for the front side windows. Tinting of back windows is not regulated. In practice, however,
bribes are often used to pass inspection or avoid road police tickets even with illegal tint.
* United Arab Emirates— Previously, window tinting was banned in the UAE]. Then the law was changed and 30 per cent was allowed. In 2017, the Federal Traffic Law was revised again. Now, people can tint their windows to 50 per cent. However, taxis and trucks are not allowed to tint their windows to 50 per cent.
* United Kingdom— Regulations set forth by the
Vehicle & Operator Services Agency under the Road Vehicles (Construction and Use) Regulations 1986 state that the front windscreen can have no less than 75 percent VLT and the front side windows no less than 70 percent. For vehicles registered prior to 1 April 1985, the front windscreen and front side windows must allow a minimum of 70% visible light through.
British police are increasingly cracking down on illegal tinting on vehicles although window tints are not checked on the annual MoT Test.
* United States—
Each state has different limits of allowable tint as measured on the front side windows. These range from a low VLT of 24% in Washington,
[RCW 46.37.430 Safety glazing - Sunscreening or coloring](_blank)
(see 5d & e for exceptions). Washington State Legislature. Revised 4 January 2012. Accessed 21 April 2012. to 88% in California,
[State WIndow Tinting Rules & Laws](_blank)
International Window Film Association. 13 October 2015 with less stringent restriction being common for windows in the rear of the vehicle. Full details of glazing and sticker laws can be found at the
Federal Motor Carrier Safety Administration
The Federal Motor Carrier Safety Administration (FMCSA) is an agency in the United States Department of Transportation that regulates the trucking industry in the United States. The primary mission of the FMCSA is to reduce crashes, injuries and f ...
website.
See also
*
One-way mirror
A one-way mirror, also called two-way mirror (or one-way glass, half-silvered mirror, and semi-transparent mirror), is a reciprocal mirror that appears reflective on one side and transparent at the other. The perception of one-way transmission i ...
*
Smoked glass
Smoked glass is glass held in the smoke of a candle flame (or other inefficiently burning hydrocarbon) such that one surface of the sheet of glass is covered in a layer of smoke residue. The glass is used as a medium for recording pen traces in sc ...
*
Smart glass
Smart glass or switchable glass (also called a smart window or switchable window) is a glass or glazing whose light transmission properties dynamically alter to control the passage of solar irradiation into buildings. In general, the glass chan ...
*
Window insulation film
References
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