Does glass block UV?

Many people believe that UV rays cannot travel through glass. However, there are different types of UV rays, some of which are blocked by glass, and others which are still able to get through. These unfiltered rays can cause damage to skin as well as upholstery and artwork.

Ultraviolet Light

On the electromagnet spectrum, ultraviolet light (UV) is located between violet visible light and x rays, and has wavelengths ranging between 200nm-400nm.

Ultraviolet light is split into 3 types, depending on the wavelength:

• UVA, 320-400nm,
• UVB, 290-320nmm
• UVC, 200-290nm

What are the risks of UV exposure?

UVC rays are absorbed by the ozone layer, but UVB and UVC rays pass through.

UVB rays are the those commonly associated with sunburn, and can cause visible damage to skin.

UVA rays are more pervasive, and are known to cause damage to the skin cells that are beyond the outer layer of skin. Even though you cannot necessarily SEE the damage (unlike sunburn), it still causes damage to skin cells, which has been linked to skin cancer and accelerated aging of skin. UVA rays are also those which cause damage and fading to upholstery and artwork.

How much UV does glass filter?

UVC rays are absorbed by the ozone layer, so are not an issue.

The majority of UVB rays are absorbed by clear untreated glass, however some still pass through. This is why we can still get sun burn through glass if exposure is long enough.

Clear Untreated Glass offers little to no protection against UVA rays, the most damaging. Approximately 75% of UVA rays are able to pass through regular glass.

Protection against UV

Laminated Glass
Laminated glass (such as that found in car windscreens) offers high (but not complete) projection against UVA. In buildings it is used as security glass, and can be expensive to install.

Tinted glass
Installing tinted glass can reduce UVA transmission by roughly half, however the tint also blocks out a similar amount of natural light.

Window Films
There are a wide range of window films available, from dark tinted to completely clear.

All of our window films block up to 99.9% of UV rays.

Our clear “UV” window films are designed to block UV rays whilst still allowing the natural, visible light through. The film is unnoticeable once installed and the view through the window remains unchanged.

Window film is a cost-efficient, retrofit solution as opposed to replacing the glazing with brand new treated glazing.

Summary

As there are different types of glazing, the amount of UV that is able to pass through it is dependent on the specific type of glazing. Either way though, glazing offers no real protection against the damaging UV rays.

Window Film is a simple solution to help protect your skin, as well as damage to artwork and upholstery.