The damaging effects of the sun are well established. Exposure to ultraviolet radiation contributes to skin ageing and is the main cause of skin cancer. Sun protection methods are extremely important in preventing these damaging effects. One method is to wear sun protective clothing.
What is sun protective clothing and UPF?
Sun protective clothing is clothing that is manufactured from ultraviolet (UV) protective fabric. The definition of a sun protective fabric is a fabric that must achieve a minimum UV Protection Factor (UPF) rating of at least UPF15 after the equivalent of 2 years of normal wear and tear. UPF is similar to SPF (sun protection factor) used to rate sunscreens, but UPF is the rating used to measure the UV rays that pass through fabrics when exposed to UV radiation. UPF ratings are shown in the table below.
- UPF 15 or 20: Good protection
- UPF 25, 30, 35: Very good protection
- UPF 40, 50, 50+: Excellent protection
In New Zealand, genuine sun protective clothing must be made from fabric that complies with the standard AS/NZS4399:1996. Clothing that has met this standard will carry a label stating one of the UPF ratings as shown in the table above.
Much research is going into producing sun protective fabrics. A team at the University of New South Wales in Australia has developed a material that looks like pure close-knit cotton with a UPF of 100. Research has shown that a simple white cotton T-shirt only provides the same protection as applying a sunscreen with SPF 5. The amount of protection fabric provides depends on the type of fabric and the weave or knit of the fabric. In general, the tighter the weave or knit, the higher the UPF.
Fabrics that provide better protection include:
- Specially manufactured fabrics for sun protection
- Blue or black denim jeans
- Merino wool garments
- 100% polyester
- Shiny polyester blends
- Satin-finish silk of any weight
- Tightly woven fabrics
- Unbleached cotton
Fabrics that provide poor protection include:
- Polyester crepe
- Bleached cotton
- Knits, especially loosely woven
- Undyed, white denim jeans
- Threadbare, worn fabric
It is not necessary to buy clothing made from specially manufactured sun protective fabric, as a wide variety of everyday apparel will provide some protection. To assess protection simply hold the material up to a window or lamp and see how much light gets through. Less light filtering through means greater protection. In addition, darker colours provide more protection than fabrics of the same material in light colours.
Many fabrics, including special sun-protective clothing, will have their protection reduced, some by as much as half when they get wet. This is especially true for wet cotton; silk and viscose may be more protective when wet.
Where can I get sun protective clothing?
Sun protective clothing made from UV protective fabric is available from many stores; just look at the labelling to make sure it complies with the standard and has a UPF rating. There are numerous Internet sites that market sun protective clothing.
By following the simple tips below, you can protect yourself from the sun with the clothes you already own.
- Choose clothing made from fabrics that provide better protection, e.g. 100% polyester (high UPF as it contains a benzene ring that absorbs UV light)
- Wear dark clothing instead of white. Dark colours provide five times more protection than white because the dye absorbs UV rays.
- Choose clothing that is made from tightly woven fabrics
- Wear long sleeves, long pants, long skirts and shirts with collars and high necklines
- Wear loose-fitting clothing – the folds in loose clothing double the fabric’s sun protection
- Cover up with dry clothes after swimming or getting wet
- Wash clothes with detergents that contain optical fluorescent brighteners to make clothes appear whiter or brighter. These act like dyes and improve the UV absorption of fabric so making them more sun protective.