How to Reduce Sun Damage and Fading

Written by Garry Kline on . Posted in faq

Short Answer: Window tinting films reduce the rate of fading by blocking 99% of the ultra violet (UV) spectrum and by reducing heat and light. A film like Ambiance 75 which blocks 99% of the UV spectrum, 75% of the Infra-red spectrum (heat) and 77% of the visible light spectrum will reduce the rate of fading of carpets, curtains and furnishings by about 78%. This means your things will last a lot longer – the amount of fading that would normally be expected after 3 years will take 10 years with the film installed


Fading costs the average homeowner hundreds of dollars every year in damage to fabrics, furnishings and flooring.

 But what exactly causes fading?

what_causes_fading

While many people would answer "sunlight", most fading damage is caused by only a small part of the sun's energy - the portion called ultraviolet radiation.

Though ultraviolet (UV) comprises only 2% of the sun's energy, it accounts for an estimated 40% of the damage to fabrics and furnishings.

Windows and Fading

Sunlight through windows has long been associated with fabric fading. Ordinary clear window glass lets in about 70% of the sun's UV radiation. To suppress fading damage, homeowners often install lined draperies and curtains, shutters, tinted or reflective glass, or dark window films.

While all of these "solutions" reduce fading, they also prevent light from passing freely through the window, negating much of the value of having windows in the first place. Draperies, curtains, and shutters all require the resident to operate them faithfully.

The Solar Spectrum

The sun's energy is made up of three distinct parts, as shown in Figure 1: ultraviolet radiation, visible radiation, and near-infrared radiation.

solar_radiation

What make these types of radiation (or energy) different from one another are the wavelengths that characterize them, much like TV and radio stations use signals with different wavelengths. [These wavelengths are commonly measured in nanometres (nm). A nanometre is very small-even a human hair is over 100,000 nanometres thick.]

Ultraviolet radiation, which is invisible to the human eye, has the shortest wavelengths of the three types of solar radiation, from 300 to about 380 nm. The next-shortest wavelengths are those of visible light from about 380 to 780 nm, while the near-infrared radiation (sometimes called invisible solar heat) has the longest wavelengths, from 780 to 4045 nm.

Relative Damage of Different Solar Wavelengths

Work by numerous scientists, including Albert Einstein, has proven that the shorter the wavelength of solar radiation, the greater the fading damage potential. Therefore, ultraviolet radiation is the most damaging, followed by the shorter-wavelength visible light. Visible light at wavelengths above about 600 nm as well as near-infrared radiation seems to cause very little fading.

uv_damage

The most authoritative research on quantifying fading damage was done in the early 1950's by the United States National Bureau of Standards (NBS). This research was undertaken for the U.S. Library of Congress, in order to design a glass filter to protect the original copies of the Declaration of Independence and the Constitution. The NBS found the relationship between the wavelength of the radiation and the relative damage to be as indicated in Figure 2. Using this relationship, scientists have calculated that blocking the entire ultraviolet radiation portion of the solar spectrum would not eliminate fading damage for most fabrics, but will slow down the rate of fading by a factor of about three. That is, a fabric that will fade by a certain amount in 3 years under normal solar exposure could take about 10 years to fade to the same point if the ultraviolet radiation is eliminated.

Smart Films - A Breakthrough in Solar Control Film Technology

The key to Smart Films performance, both for heat control and for fading protection, is that it is a "selectively transmitting" material. Standard window films act like a sun shade and block all parts of the solar spectrum. Smart Films has been engineered to transmit parts of the sun's spectrum, such as visible light that we want while blocking others, such as UV and infrared radiation (heat). This is why Smart Films block more heat and allow in twice as much visible light as standard window films.

Ordinary clear window glass lets in up to 70% of the sun's UV rays. New varieties of high-performance window glass, commonly called "low-e" glazing, provide some protection from UV radiation. Even the best of these, however, still transmits 11% - 26% of the damaging UV radiation.  Since UV radiation is invisible to the eye, and is the major cause of fading for most fabrics, it should ideally be eliminated.

Smart Films transmits less than one 1% of UV radiation - 50 times less than competitive "Low-e" window glass and more than 100 times less than double-pane glass - while maintaining high visible light transmission – twice as much as standard window films


Questions and Answers about Fading and Smart Films

  • Do Smart Films prevent fabric fading? Are my drapes, furniture, and carpets guaranteed not to fade?

Many factors contribute to fading in addition to ultraviolet radiation: portions of the visible light spectrum, humidity, heat and air quality. Although ultraviolet radiation accounts for an estimated 40% of the fading damage, these other factors will fade fabrics even if all of the ultraviolet radiation is blocked. Hence, Smart Films, which blocks over 99% of the ultraviolet radiation, will delay, but not eliminate fading. It is important also to remember that not all fabrics fade at the same rate. The type of dye, fibre, finish, and the method in which the dye was applied to the fabric affects fading rates. Although fading will continue to occur with Smart Films installed, fabric life will be prolonged significantly.

  • Will Smart Films keep fine woods from bleaching and paintings from fading?

When exposed to the sun's radiation, unfinished wood typically bleaches and wood finishes become yellow or darken. Ultraviolet radiation plays a key role in this, but the importance of its role is different for every wood/ finish combination. Near elimination of UV radiation will delay, but not eliminate wood discoloration. Similarly, UV affects paintings to different degrees depending on the media used. Watercolours, for example, are highly susceptible to UV degradation. Eliminating UV will extend the life of paintings, but care should be taken to be sure that owners of artwork realize that fading is caused by many factors besides UV radiation.

  • Other window products claim to block UV – how is Smart Films different?

While "low-e" window glass does block some of the damaging ultraviolet radiation, most of these still transmit 11% - 26% or more of the damaging UV rays. Smart Films transmit less than one 1% of the ultraviolet radiation. Standard window films block up to 99% of the ultraviolet radiation but also block up to 90% of the natural light entering a room.

  • Don't plants need UV radiation to grow?

Many studies have shown that red and blue visible light are the portions of the solar spectrum most effective in increasing photosynthesis, and hence plant growth. Therefore, eliminating ultraviolet radiation should not affect the growth of houseplants. Furthermore, since Smart Films also filter out much of the infrared radiation, which can scorch leaves, and reduces temperature swings, which can shock plants, windows with Smart Films should improve the growth of most plants.

  • Isn't UV protection important only in summer?

Even in cold, cloudy climates, UV radiation causes damage to furnishings. Clouds tend to block visible and near-infrared energy more completely than ultraviolet radiation' So, even if you can't feel the warmth of the sun, UV radiation is still getting to your furnishings. Just as one can get sunburnt on a cloudy day, furnishings can suffer damage during cloudy conditions.

  • Do you need Smart Films for south facing windows?

Yes. The diffused light that comes in windows that face the south contains about 70% of the damaging UV radiation that comes in windows with direct sun exposure.

  • Will the performance of Smart Films change over time?

Smart Films has developed a high degree of confidence in its products through extensive long-term durability testing. In field testing, accelerated testing, and industry standard testing, there has been no discoloration, no film sagging or wrinkling, no degradation of performance, and no evidence which would suggest that changes in appearance or performance will occur. Smart Films back their product with a Lifetime Warranty.

  • Do Smart Films look like ordinary glass?

Smart Films range from a clear and nearly colourless film that looks like ordinary window glass through to films that provide good privacy and glare reduction, which give windows a darkened appearance when viewed externally.

 
                           
                       

                                                                       

                           
                       
 
               
 
           
       
   
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