For our UV protective apparel we only use materials where the UV protection is not achieved via chemical treatment. Instead, the protective function results from the use of special yarns and/or fabric constructions (e.g. extremely dense weaves).
Advantages:
The function is integrated into the fabric itself
The protection is long-lasting and is not diminished by perspiration or contact with water
The UV protection factor is also suitable for intense sunlight (UVA + UVB protection)
Apparel with an UV protection factor of 40+ quotes the EN 13758-1:2001+A1:2006 standard. Only covered areas are protected. The protection may be reduced with use or if stretched or wet.