The Ultraviolet Protection Factor (UPF) rating system measures the UV protection provided by fabric. It is very similar to the SPF rating system used for sunscreens.
A garment with a UPF of 50 only allows 1/50th of the UV radiation falling on the surface of the garment to pass through it. In other words, it blocks 49/50ths or 98% of the UV radiation.
Our Supplier Partner Factory uses independent laboratories for our sun protective clothing tests. We conduct an initial UV transmittance test, then launder the garment 40 times, expose it to 100 fading units of simulated sunlight, then conduct a second UV transmittance test. The tests measure transmittance across both the UVA and UVB spectrum. Garment ratings are based on the lower result of the initial “brand new” test and the second “life cycle” test. Most fabrics lose some level of UV protection as they age, so most fabrics are rated based on their second test. The main exception is cotton or cotton-blend fabrics that can shrink as they age and can be weakest when they are brand new.
Certification of UV protection levels is needed as most regular summer clothing rates below a SPF 30 sunscreen in terms of UV protection.A journal Gambichler in the USA examined the level of UV protection provided by 236 different articles of clothing and found that fewer than half the fabrics provided as much protection as a SPF 30 sunscreen. They concluded it was difficult for sun-aware consumers to choose the “right” garments unless they were tested and labeled in accordance with appropriate standards.
There are a number of factors that affect the level of ultraviolet protection provided by a fabric and the UPF rating. In order of importance these are: weave (tighter is better), color (darker is better), weight (also called mass or cover factor – heavier is better), stretch (less is better) and wetness (dry is better). The other major factor that affects protection is the addition of chemicals such as UV absorbers or UV diffusers during the manufacturing process. Many factors that make a garment comfortable also make it less protective. The major design challenge for sun protective clothing is how to combine comfort, style and protection in the one garment.
We use a range of different UPF 50+ rated fabrics in our UV protective clothing. Each fabric offers a unique combination of weight, hand, color, stretch, drape, wicking, breathability and UV protection. Our designs use hidden ventilation and specialized moisture managing UPF 50+ rated fabrics to achieve these dual goals of comfort and maximum skin coverage.