UV protection of textiles
What you need to know about the UV protection of textiles to protect you from the sun
UV rays permeate clothes and can thus cause sunburn and severe skin diseases. To avoid this, the textiles are being produced with UPF protection (Ultraviolet Protection Factor). This indicates by which factor the respective piece of clothing prolongs the duration the person wearing this item can stay in the sun without risking sunburn.
The UV permeability (transmission) of a fabric is measured by means of a spectral photometer, thus indicating the UPF.
Regular, dry cotton shirts have a UPF of 5-8, when wet they have a UPF of 3. Thus, a t-shirt is way below the UPF 50 defined by the Skin Cancer Foundation as the minimum protection required. Textiles certified according to the Australian & New Zealand standard AS/AZ 4399 (fabric test when new) should at least show a UPF of 50 since the protection goes down when the item gets wet or stretched.
The UV standard 801 introduced in 2001 makes use of tests such as stretching, permeability and wearout (40 washes). UV protection can be achieved by compact fabric constructions, chemical additions or incorporating of pigments or clay minerals which absorb and/or reflect UV rays. It is important for the UV protection to be guaranteed even after several washes.
The protection indicated on the label of clothes to the buyers corresponds to the lowest value measured during the usage test. A piece of clothes with a protection factor of 20 according to the UV standard 801 allows you to stay in the sun 20 times longer than without this textile sun protection.
Light transmission
The more compact the fabric, the less rays can permeate it.
Would you like to test your clothes on your own? Then stretch the fabric by hand and hold it against the light. If no light shines through, the protection is good no matter whether the fabric is dry or wet.
Please note: In the sun, darker colours are preferable since they absorb more rays when the material is sufficiently compact. Careful with net-like or transparent fabrics! They offer no or hardly any protection which is why you need to put on sunscreen underneath. Clothes should not be too tight because the more you stretch a fabric the more light permeates it and the less protection it offers.
Tip:
Even when wearing UV-safe clothes, do put on sunscreen, wear sunglasses and a hat!
