Whether you have heard about SPF clothing or not, it’s only natural to approach the subject with a certain level of incredulity. The technical term for the rating system used to measure clothing that is manufactured specifically to protect against the sun’s radiation is UPF, also known as ultraviolet protection factor. So how does anyone know if a swimwear or another clothing item really does offer protection against the sun? You certainly can’t tell by looking at it! Here’s how the rigorous testing for SPF clothing occurs:
Various governing bodies all over the world have created their own standards against which each item of SPF clothing is tested.
The testing agency transmits ultraviolet light through the fabric of the garment.
A device is used to measure the radiation that comes through. Usually fabrics undergo testing while they are dry and before they become stretched out.
The amount of radiation that gets through the fabric is then translated into a UPF rating. If less than 2 percent of the UV radiation gets through, then the item achieves a 50+ UPF, which is the highest level available in clothing.
In each country there is also a government entity that keeps an eye on swimwear manufacturers and swimwear distributors that claim their swimwear or clothing offers UV protection. A quality manufacturer should use an independent, third-party lab to test their garments and receive their UPF ratings.
In cases where products are sold in a variety of colors, the testing laboratory typically checks the fabric with the lightest color because darker fabrics tend to absorb more UV radiation and thus, have higher UPF ratings. However, sometimes all colors of a product are tested to ensure that it does achieve the promised UPF rating on the label.
Aside from standard questions about testing on SPF clothing, some consumers also want to know whether the protection will wear off over time and numerous launderings. The good news is that this has been tested as well. A 1998 study published in Textile and Colorist indicated that no matter which kind of laundry detergent was used, the UPF rating was not reduced due to repeated washings. In fact, the study showed that washing these sun protective garments actually increased the UPF in some cases.
So for those who are a bit skeptical about whether clothing can really protect against the sun, there is plenty of scientific evidence proving that this is entirely possible. Probably what’s most important to understand about this evidence is that it’s trustworthy because it is not being provided directly by the manufacturers of these products.