The terms nanotechnology and nano-particle are used quite frequently in today’s discussions of advanced window film technology. Are they overused and or misused? Maybe … It’s important to know what these terms mean and how they relate to window film design and construction.
The word nanotechnology is an umbrella term used for anything that is 100 nanometers or less in size. This is very small at the intercellular level. The term is fairly new however the manipulation of molecules has been around for quite some time.
Many different substances can be broken down to nano-sized particles. In relation to window film, these particles are used as coatings to control solar energy.
What Does “Ceramic” Mean?
The term ceramic is frequently used when nitrate and oxide coatings are used in window film construction. During the coating process, nitrogen and/or oxygen are introduced into the sputtering chamber in conjunction with a negative electrical charge and argon gas. By introducing these gases, the target metal is transformed into a non-metal state. The appearance of the coating changes drastically and is less reflective in appearance compared to a metalized coating. Hence the term ceramic, as the coating is no longer metal with metal properties and appearance.
Why are we talking about Infrared Heat Rejection in Window Films ?
Claims about “infrared rejection” or other infrared controlling characteristics imparted to glass by solar control window film are becoming abundant in current marketing literature, but the claims that are being made do not always reflect the true performance of the product in rejecting heat.
There is no formally recognised measurement of infrared rejection by the fenestration (window) industry,and as a result, a few manufacturers previously decided to publish“IR Rejection” values at specific wavelengths or over a narrow range 900-100nm Suntek and others are now calling this the selective IR . This methodology results in an incomplete assessment of the solar infrared energy, since the energy across the infrared portion of the solar spectrum varies widely, 780 to 2500 Nano meters. Most reputable film manufacturers now refer to this as IR rejection but will also give you the Selected 3M version for comparison.
Measuring IR at a single point or in a small range does not encompass the total amount of heat gain caused by the infrared component of the spectrum, only a small part of it. It is critically important to become informed about the entire solar energy spectrum, not just one factor in the range, as well as the additional effects of absorption on heat gain.
An understanding of solar energy is required to fully understand infrared rejection claims. The Solar Spectrum is made up of Visible light (49%), UV (2%) and Infrared or NIR (49%).
Visible Light reaching the surface of the earth that can be seen by humans is located between the wavelengths of 400 and 780 nanometres (nm) in the spectrum. It accounts for 49% of the overall solar energy from the sun but only 43% of the Heat. As the Visible light hits a surface the heat builds on that surface.
UV, or Ultraviolet Light falls between 100 nm to 380 nm and is not visible to the human eye. This energy is highly energetic and destructive (Skin Cancer, Burning, Fading) but, when considering heat the amount of energy it carries is small compared to the amount of energy contained by visible and infrared light. This form of light only accounts for 3% of the heat.
Last, the remaining energy is Infrared Radiation. The near infrared portion of the solar spectrum runs from approximately 780 nm to 2,500 nm and carries about 49% of the solar energy – just under half of the total solar energy. Although it accounts for 53% of the heat from the sun! Technically, radiation beyond 2,500 nm is also infrared, but this “long wave” radiation is a very small portion of the total solar energy and is mostly associated with radiation from room temperature and warm objects. It is widely accepted that the NIR radiation is 780 nm to 2500 nm, meaning the entire NIR “band” is 1,720 nm wide.
Some window film companies elaborate on the fact that their window films have an amazing SPF factor 75+ or that they are recommended by the Cancer Foundation.
Just to be clear!.... All the reputable automotive films have equivalent SPF of around 300, due to the fact they stop 99% of UV. The SPF rating given by ARPANSA only goes to 50+ as the rating system was designed for clothing so anything above 50 is not correct.
Window film is obviously amongst the best protection against skin cancer, and recommended by various cancer prevention organisations.
The cancer council of Victora has come to arrangement with a particular in commercial arrangement and are permitted to use their logo on a dealership film a result.
Customers may well get a better film off you, for a substantially cheaper price and with all the money they save,they might donate some of that to the money to the Cancer foundation.... should they choose.
We have ARPANSA reports on all our films should you want a copy.
WE sell and highly recomend the Suntek CIR and the Avery NR PRO films in this Category