Sun protective clothing is

clothing Clothing (also known as clothes, garments, dress, apparel, or attire) is any item worn on a human human body, body. Typically, clothing is made of fabrics or textiles, but over time it has included garments made from animal skin and other thin s ...

specifically designed for sun protection and is produced from a

fabric Textile is an umbrella term that includes various fiber-based materials, including fibers, yarns, filaments, threads, and different types of fabric. At first, the word "textiles" only referred to woven fabrics. However, weaving is no ...

rated for its level of

ultraviolet Ultraviolet radiation, also known as simply UV, is electromagnetic radiation of wavelengths of 10–400 nanometers, shorter than that of visible light, but longer than X-rays. UV radiation is present in sunlight and constitutes about 10% of ...

(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, ankle-length trousers, knee- to floor-length skirts, knee- to floor-length dresses, and collars are common styles for clothing as a sun protective measure. Regular clothing can leave you 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 Fiber (spelled fibre in British English; from ) is a natural or artificial substance that is significantly longer than it is wide. Fibers are often used in the manufacture of other materials. The strongest engineering materials often inco ...

structure,

density Density (volumetric mass density or specific mass) is the ratio of a substance's mass to its volume. The symbol most often used for density is ''ρ'' (the lower case Greek letter rho), although the Latin letter ''D'' (or ''d'') can also be u ...

of weave, and dye components, especially darker colors and

indigo InterGlobe Aviation Limited (d/b/a IndiGo), is an India, Indian airline headquartered in Gurgaon, Haryana, India. It is the largest List of airlines of India, airline in India by passengers carried and fleet size, with a 64.1% domestic market ...

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 Polyester is a category of polymers that contain one or two ester linkages in every repeat unit of their main chain. As a specific material, it most commonly refers to a type called polyethylene terephthalate (PET). Polyesters include some natura ...

nylon Nylon is a family of synthetic polymers characterised by amide linkages, typically connecting aliphatic or Polyamide#Classification, semi-aromatic groups. Nylons are generally brownish in color and can possess a soft texture, with some varieti ...

, spandex and

polypropylene Polypropylene (PP), also known as polypropene, is a thermoplastic polymer used in a wide variety of applications. It is produced via chain-growth polymerization from the monomer Propene, propylene. Polypropylene belongs to the group of polyolefin ...

. Natural or synthetic indigo-dyed

denim Denim is a sturdy cotton warp-faced textile in which the weft passes under two or more Warp (weaving), warp threads. This twill weave produces a diagonal ribbing that distinguishes it from cotton duck. Denim, as it is recognized today, was f ...

twill Twill is a type of textile Textile is an Hyponymy and hypernymy, umbrella term that includes various Fiber, fiber-based materials, including fibers, yarns, Staple (textiles)#Filament fiber, filaments, Thread (yarn), threads, and d ...

weaves,

canvas Canvas is an extremely durable Plain weave, plain-woven Cloth, fabric used for making sails, tents, Tent#Marquees and larger tents, marquees, backpacks, Shelter (building), shelters, as a Support (art), support for oil painting and for other ite ...

and

satin A satin weave is a type of Textile, fabric weave that produces a characteristically glossy, smooth or lustrous material, typically with a glossy top surface and a dull back; it is not durable, as it tends to snag. It is one of three fundamen ...

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 Sunburn is a form of radiation burn that affects living tissue, such as skin, that results from an overexposure to ultraviolet (UV) radiation, usually from the Sun. Common symptoms in humans and other animals include red or reddish skin tha ...

-causing UV without and with the protection of the fabric, similar to SPF ( sun protection factor) ratings for

sunscreen Sunscreen, also known as sunblock, sun lotion or sun cream, is a photoprotection, photoprotective topical product for the Human skin, skin that helps protect against sunburn and prevent skin cancer. Sunscreens come as lotions, sprays, gels, fo ...

. 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 Australia, officially the Commonwealth of Australia, is a country comprising mainland Australia, the mainland of the Australia (continent), Australian continent, the island of Tasmania and list of islands of Australia, numerous smaller isl ...

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 American(s) may refer to: * American, something of, from, or related to the United States of America, commonly known as the "United States" or "America" ** Americans, citizens and nationals of the United States of America ** American ancestry, p ...

(ASTM) Committee D13.65, at the behest of the

Federal Trade Commission The Federal Trade Commission (FTC) is an independent agency of the United States government whose principal mission is the enforcement of civil (non-criminal) United States antitrust law, antitrust law and the promotion of consumer protection. It ...

(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 The United States Food and Drug Administration (FDA or US FDA) is a List of United States federal agencies, federal agency of the United States Department of Health and Human Services, Department of Health and Human Services. The FDA is respo ...

(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 Color (or colour in English in the Commonwealth of Nations, Commonwealth English; American and British English spelling differences#-our, -or, see spelling differences) is the visual perception based on the electromagnetic spectrum. Though co ...

weight In science and engineering, the weight of an object is a quantity associated with the gravitational force exerted on the object by other objects in its environment, although there is some variation and debate as to the exact definition. Some sta ...

, 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 BASF SE (), an initialism of its original name , is a European Multinational corporation, multinational company and the List of largest chemical producers, largest chemical producer in the world. Its headquarters are located in Ludwigshafen, Ge ...

embedded nanoparticles of

titanium dioxide Titanium dioxide, also known as titanium(IV) oxide or titania , is the inorganic compound derived from titanium with the chemical formula . When used as a pigment, it is called titanium white, Pigment White 6 (PW6), or Colour Index Internationa ...

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 The University of Alberta (also known as U of A or UAlberta, ) is a public research university located in Edmonton, Alberta, Canada. It was founded in 1908 by Alexander Cameron Rutherford, the first premier of Alberta, and Henry Marshall Tory, t ...

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

UPF rating

A relatively new rating designation for sun protective textiles and clothing is UPF (ultraviolet protection factor), which represents the ratio of sunburn-causing UV measured without and with the protection of the fabric. For example, a fabric rated UPF 30 means that, if 30 units of UV fall on the fabric, only 1 unit will pass through to the skin. A UPF 30 fabric that blocks 29 out of 30 units of UV is therefore blocking 96.7%. Unlike SPF (sun protection factor) measurements that traditionally use human sunburn testing, UPF is measured using a laboratory instrument ( spectrophotometer or spectroradiometer) and an artificial light source, and then applying a sunburn

weighting curve A weighting curve is a graph of a set of factors, that are used to 'weight' measured values of a variable according to their importance in relation to some outcome. An important example is frequency weighting in sound level measurement where a spec ...

(erythemal action spectrum) across the relevant UV wavelengths. Theoretically, human SPF testing and instrument UPF testing both generate comparable measurements of a product's ability to protect against sunburn. Below is the ASTM Standard for Sun Protective Clothing and Swimwear: According to testing by ''

Consumer Reports Consumer Reports (CR), formerly Consumers Union (CU), is an American nonprofit consumer organization dedicated to independent product testing, investigative journalism, consumer-oriented research, public education, and consumer advocacy. Founded ...

'', UPF 30+ is typical for protective fabrics, while UPF 20 is typical for standard summer fabrics.

UPF testing protocol

Developed in 1998 by Committee RA106, the testing standard for sun protective fabrics in the United States is the American Association of Textile Chemists and Colorists (AATCC) Test Method 183. This method is based on the original guidelines established in Australia in 1994. AATCC 183 should be used in conjunction with other related standards including ASTM D 6544 and ASTM D 6603. ASTM D 6544 specifies simulating the life cycle of a fabric so that a UPF test can be done near the end of the fabric's life, when it typically provides the least UV protection. ASTM D 6603 is a consumer format recommended for visible hangtag and care labeling of sun protective clothing and textiles. A manufacturer may publish a test result to a maximum of UPF 50+. Sun protective clothing and textile/fabric manufacturers are currently a self-regulating industry in North America, prescribed by the AATCC and ASTM methods of testing.

Notes

References