Sun protection of military equipment is literally a hot topic. Nowadays, army forces mostly operate in conflict areas with extreme climates, for example the deserts of Afghanistan. From a medical point of view, the right textiles offer a distinctly better protection from the harmful effects of the sun than cosmetic sun protection do.
As the most important and most vulnerable part of a mission, soldiers are likely to experience extreme solar intensity and severe heat stress; both must be managed for successful mission accomplishment. Appropriate functional clothing systems with a sufficient UV protection can help prevent health damages like hyperthermia or skin cancer. Especially helmets and camouflage jackets should be equipped with sufficient UV protection as these cover body parts that show most sensitivity to sun damages.
But how in fact do textiles protect you from the sun’s radiation, and what differences between them should be taken into account? Dr Andreas Schmidt of the international Textile Research Centre at the Hohenstein Institute in Bonnigheim in Germany has the facts.
Why do special UV protection textiles provide even better protection than cosmetic sun blockers with a high sun protection factor (SPF)?
The sun protection is built into the processed chemical fibres. Titanium dioxide particles, the same as we find in powders and sunscreen, are incorporated into the fibres and act like tiny mirrors, reflecting the high-energy UV rays and therefore are protecting the skin beneath. In addition, the UV protection in sun protection textiles is further increased by a special construction of the fabrics, such as laying several layers on top of one another, covering the gaps between the fibres that inevitably occur in woven or knitted fabrics.
What criteria determine the UV protection factor of textiles?
The composition of the material, the kind of fabric and the weight, the colour and surface-finish of the materials have an important effect on the UV protection factor (UPF) of a textile material.
What role does the colour of a textile material for the UV protection play?
Dark colours, as used for most military uniforms, generally give better UV protection than pale colours, because the dyeing pigments absorb UV radiation. This is why Tuareg people, who live in the Sahara, have been dyeing their clothing dark blue for centuries. Today, thanks to chemical treatments like UV absorbers, it is also possible to achieve similar results with lighter coloured fabrics as for example used in camouflage.
Why do natural fibres only offer limited protection from UV radiation?
The UV protection, provided by natural fibres such as cotton or linen, is relatively low. A white t-shirt has an UV protection factor of 10-15. The reason for this is that cotton fibres in themselves reflect or absorb a little UV radiation. This is particularly true once they have become wet – the fibres then become almost see-through. In addition, cotton fibres are kidney-shaped in diameter, for example within one fibre the diameter can be very variable. When this is combined with a twisted fibre structure, quite large holes appear in woven or knitted fabrics, through which the UV radiation can penetrate unhindered to the skin below.
Are there any natural fibres with a good UV protection factor?
Natural silk has a relatively high UV protection factor, because, like modern synthetic fibres, it contains matting components that reflect and absorb UV rays. The regular fibre structure, with small gaps in woven or knitted fabrics, also prevents the UV radiation from reaching the skin. Depending on the colour, the UPF may be 20 to 30. There is a good reason why in India, for example, silk sarongs are worn wrapped in several layers, which significantly increase the UV protection factor.
How is the UV protection factor of textiles indicated?
The protection from UV radiation that textiles provide is indicated as a UV protection factor (UPF = Ultraviolet Protection Factor). This equates to the sun protection factor (SPF) for sun creams and indicates the factor by which the skin’s own natural protection time – which depends on your individual skin type – is extended by the textile material. The skin of a person with skin type one, for example, with red or blond hair, blue eyes and a very pale complexion, has a natural protection time of about five to ten minutes. If such a person is exposed to strong sunlight for any longer without protection, they risk dangerous sunburn.
If they are protected by a textile material with UPF 80, they can extend the length of time they can remain in the sun by eighty times, without causing any skin damage. That is to say, to a maximum of 6.5hr – 13hr (80min x 5min = 400min to 80min x 10min = 800min). However, care must be taken to ensure that all parts of the body not covered by textiles are given additional protection with sun cream. Instead of the UPF, the manufacturers of UV protection textiles often quote what percentage of the UV radiation is blocked by their products.
How can consumers evaluate this information?
Such statements are very difficult to interpret. If, for example, 95% of the UV rays are blocked, that equates to a UPF of 20. So if you really want to be on the safe side when you buy UV protection textiles, you should always ask detailed questions, have the information carefully explained to you and compare it with your personal requirements, which depend partly on your personal skin type and the resulting natural protection time.
You recommend that the UPF is measured in accordance with UV standard 801. Why?
The UV standard 801 was developed in 1998 to overcome the weaknesses in the previous test standard called the Australian / New Zealand standard (AS/NZ 4399:1996). This did not take the stresses and strains imposed during washing and regular use into account. By contrast, under the UV Standard 801, the UPF of a textile is determined not only when it is new, but also when it has been stretched and wetted, after mechanical strain and washing as well as after artificial weathering.
How many companies have their products tested using this method?
There are now over 100 companies making a variety of products offering high UV protection who have them tested and / or certificated under UV Standard 801. On the UV standard 801 website you can see a selection of companies that endorse their products using UV Standard 801.
What kinds of products are mainly assessed under UV standard 801?
We recommend the measuring procedure under UV standard 801 because it produces highly practical results for shading textiles like sunshades and blinds and all kind of clothing textiles. Besides military clothes, the range of products extends from swimwear, leisure and trekking clothes to fabrics used for working clothes.