Sunscreen and fabric offer two main forms of outdoor protection from the sun's ultraviolet (UV) rays. It was only a matter of time before enterprising clothing manufacturers came up with a way to integrate them both into one sun busting combo that offers as much protection as a seat in the shade.
Actually, almost all clothing offers at least some protection from UV light. It can be tough getting enough protection from fabric alone, though. Of the untreated fabrics that do offer good protection, many are too thick and heavy to be comfortable in hot weather. The gauzy, lightweight fabrics most associated with spring and summer are typically sheer to encourage air flow and help keep perspiration to a minimum. A light, loose fabric weave that's great for venting perspiration and making you feel fresh when the temperatures skyrocket is also less effective at keeping ultraviolet light from penetrating through to your unprotected skin.
Warm weather clothing these days is often rated for its ability to protect the wearer from ultraviolet radiation, so look for a UPF-rating designation on the clothing you buy. The acronym UPF stands for Ultraviolet Protection Factor, and it's the apparel equivalent of a sunscreen's SPF rating. The higher the number, the greater the protection will be. A UPF rating of 50, the highest rating obtainable, only permits 2 percent of available ultraviolet radiation to penetrate a garment.
UPF protection can be added to fabrics a number of ways. The method involved will have an impact on whether or not a UPF-rated garment will lose some of its protection in the laundry:
- The weave -- One of the easiest ways to hike the UPF power of a garment is to use a tightly woven fabric. The denser the fabric (or the thicker it is), the less UV light will penetrate. A tightly woven garment can take quite a bit of laundering without losing its UV blocking ability. Over time, though, simple laundering can stretch fabric and wash away minute fibers that will eventually cause small gaps.
- The fabric -- Some synthetic fabrics are formulated to convert ultraviolet light or deflect it away. Other synthetics, like nylon and polyester, and organic fibers like silk, reflect UV light naturally. This kind of protection doesn't wash out, but as with special weaves, a fabric's fibers can become distorted over time, making them less effective at screening UV light.
- Special dyes -- Specially formulated dyes help increase a fabric's UPF rating by disrupting or reflecting UV light. They're typically pretty stable but can still lose some of their density and protective power over multiple washings.
- Chemical treatments -- Beyond the fabric, weave and dye, some garments employ chemical warfare to help repel ultraviolet light. Chemical treatments like reflective brighteners can be applied to fabric before clothing is cut and sewn at the factory. You can even treat clothes with UPF-boosting laundry additives at home. How stable a chemical treatment will be through multiple washings can vary.
To figure out how the UPF protection factors into your clothes, your best bet is to read the informational materials carefully. The tags on new clothes you buy should provide that information, so you'll know exactly what you're dealing with. That includes laundering instructions for new garments and reapplication recommendations for laundry additives like SunGuard.