Sun protective clothing is clothing specifically designed for sun protection and is produced from a fabric rated for its level of ultraviolet (UV) protection. A novel weave structure and denier (related to thread count per inch) may produce sun protective properties. In addition, some textiles and fabrics employed in the use of sun protective clothing may be pre-treated with UV-inhibiting ingredients during manufacture to enhance their effectiveness. In addition to special fabrics, sun protective clothing may also adhere to specific design parameters, including styling appropriate to full coverage of the skin most susceptible to UV damage. Long sleeves for both sexes, ankle-length trousers for men, knee-to-floor-length skirts and dresses for women, and collars for both sexes are common styles for clothing as a sun protective measure. Regular clothing can leave a person exposed to the damaging effects of UV radiation. However, a number of fabrics and textiles in common use today need no further UV-blocking enhancement based on their inherent fiber structure, density of weave, and dye components, especially darker colors and indigo dyes. Good examples of these fabrics contain full percentages or blends of heavy-weight natural fibers like cotton, linen and hemp or light-weight synthetics such as polyester, nylon, spandex and polypropylene. Natural or synthetic indigo-dyed denim, twill weaves, canvas and satin are also good examples. However, a significant disadvantage is the heat retention caused by heavier-weight and darker-colored fabrics. As sun protective clothing is usually meant to be worn during warm and humid weather, some UV-blocking textiles and clothing may be designed with ventilated weaves, moisture wicking and antibacterial properties to assist in cooling and breathability. UPF (ultraviolet protection factor) represents the ratio of sunburn-causing UV without and with the protection of the fabric, similar to SPF (sun protection factor) ratings for sunscreen. While standard summer fabrics have UPF ~6, sun protective clothing typically has UPF ~30, which means that only 1 out of ~30 units of UV will pass through (~3%).
History Although clothing has been used for protection against solar exposure for thousands of years, modern sun protective clothing was popularized (but not exclusively used) in Australia as an option or adjunct to sunscreen lotions and sunblock creams. Sun protective clothing and UV protective fabrics in Australia now follow a lab-testing procedure regulated by a Commonwealth agency: ARPANSA. This standard was established in 1996 after work by Australian swimwear companies. The British standard was established in 1998 by the National Radiological Protection Board and the British Standards Institute. Using the Australian method as a model, the US standard was formally established in 2001, and now employs a more-stringent testing protocol that includes fabric longevity, abrasion/wear and washability. UPF testing is now widely used on clothing for outdoor activities. The original UPF rating system was enhanced in the United States by the American Society for Testing and Materials (ASTM) Committee D13.65, at the behest of the Federal Trade Commission (FTC) and the Consumer Product Safety Commission, to qualify and standardize the emerging sun protective clothing and textile industry. When the Food and Drug Administration (FDA) discontinued regulating sun-protective clothing, the Solar Protective Factory (whose CEO chaired the ASTM Committee) took the lead in developing the UPF testing protocols and labeling standards that are presently used in the United States. In 1992, the FDA reviewed clothing that was being marketed with claims of sun protection (SPF, % UV blockage, or skin cancer prevention). Only one brand of sun protective clothing, Solumbra, was cleared under medical device regulations. The FDA initially regulated sun protective clothing as a medical device, but later transferred oversight for general sun protective clothing to the FTC. The UPF rating system may eventually be adopted by interested apparel/textile/fabric manufacturers as a "value added" program for consumer safety and awareness. Before UPF standards were in place (which directly measure a fabric's ability to block UV radiation), clothing was previously rated using SPF standards (which measure how long a person's skin takes to redden).
Fabric Factors that affect the level of sun protection provided by a fabric, in approximate order of importance, include weave, color, weight, stretch, and wetness. The less open or more dense the fabric (weave, weight, stretch), the better the protection. Getting a fabric wet reduces the protection as much as half, except for silk and viscose which can get more protective when wet. Polyester contains a benzene ring that absorbs UV light. In addition, UV absorbers may be added at various points in the manufacturing process to enhance protection levels. In 2003, chemical company BASF embedded nanoparticles of titanium dioxide into a nylon fabric, which can be used for sun protective clothing that maintains its UV protection when wet. There is some indication that washing fabrics in detergents containing fabric brighteners, which absorb UV radiation, might increase their protective capability. Studies at the University of Alberta also indicate that darker-colored fabrics offer more protection than lighter-colored fabrics. While there is some correlation between the percentages of visible light and UV that pass through the same fabric, it is not a strong relationship. With new-technology textiles designed for the sole purpose of UV blocking, it is not always possible to judge the UV protection level simply by holding up the fabric and examining how much visible light passes through. Provide more protection:
specially manufactured fabrics cotton viscose fabrics black or dark blue denim jeans wool garments satin-finished silk of any weight tightly woven Bamboo/Lycra fabric polyacrylonitrile 100% polyester shiny polyester blends tightly woven fabrics REPREVE fabric unbleached cotton (most cotton sold is bleached) bamboo/cotton blend Provide less protection:
polyester crepe bleached cotton viscose knits undyed/white jeans worn/old fabric
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