UV protection by clothing: an intercomparison of measurements and methods.

In an attempt to reduce the incidence of skin cancer, cancer foundations have run educational campaigns which encourage the general population to limit their solar UVR exposures. An important part of these campaigns, in particular in Australia, but also more recently in Europe and the U.S., has been the adoption of protective measures such as sunscreens, hats, sunglasses and clothing. The protective properties of fabrics and clothing against ultraviolet radiation (UVR) have been known for some time, but recently there has been considerable interest in quantifying the degree of protection. This has been generated, in part, by the requirements for occupational protection for outdoor workers as well as the provision of UVR protection for the recreational market. The quantification of UVR protection has been laboratory based using in vitro test methods. Development of a standard test method has become an important part of the testing process, and this paper presents results from an intercomparison involving five independent testing laboratories. Agreement is good, in particular for samples with protection factors below 50. Technical difficulties and sources of errors associated with the measurements are discussed.

Sun protective clothing in Australia and the Australian/New Zealand standard: an overview.

Clothing has been part of the sun protection strategy for many years. However, it is only recently that studies have been undertaken to investigate the protectiveness of fabrics and to place clinical advice on a sound scientific basis. Fabrics can now be rated and an ultraviolet protection factor assigned. Several factors influence photoprotection such as construction, stretch, hydration, colour, fibre type and various manufacturing processes. In 1996 the Australian/New Zealand Standard for sun protective clothing was published. This is the first of its kind in the world.

Sun protection by a summer-weight garment: the effect of washing and wearing.

OBJECTIVE: To assess the effect of use (washing and wearing) on the photoprotection provided by a cotton fabric. METHODS: Twenty jersey-knit pure cotton T-shirts were worn for 4-8 hours per week and washed weekly for 10 weeks. Fabric samples taken before and after use were compared. MAIN OUTCOME MEASURES: Fabric ultraviolet protection factor (UPF) was calculated from spectrophotometric ultraviolet radiation transmission data. Changes in fabric structure and hole size were determined for samples from one T-shirt by light microscopy and image analysis. RESULTS: UPF increased consistently and significantly after use, from a mean of 19.0 to 40.6. A corresponding reduction in fabric hole area was seen under the light microscope and confirmed on image analysis (from 8.0% to 3.9% of total image area). CONCLUSION: UPF of pure cotton garments may improve after use, at least in the short term. The increase is mostly accounted for by reduction in fabric hole area due to shrinkage.

A comparative study of fabric protection against ultraviolet-induced erythema determined by spectrophotometric and human skin measurements.

Historically, a textile's ability to protect against ultraviolet radiation (UVR)-induced erythema has been based on its UVR transmission. However, due to the nonuniformity of the fabric structure of a textile and its resultant nonuniform transmission, the above prediction may not hold. The fabric protection factors (FPF) of 5 metal meshes, to simulate the weave pattern and yarn dimensions of typical fabrics, and 6 textiles with variable construction (woven and knitted), fibre type and dye were determined using a spectrophotometric assay and human skin testing. All 5 meshs and 5 of the 6 textiles allowed spectrophotometric prediction of their FPF compared with off-skin (2 mm) human testing. However, on-skin human testing FPF were generally significantly lower than both the off-skin and spectrophotometric estimates. Although evidence is presented that the nonuniform nature of a textile's structure does influence its FPF predictability, in practice, properly conducted spectrophotometric analysis may yield the most typical indication of the protectiveness of a fabric against UVR-induced erythema.