I read on https://blog.coolibar.com/whats-the-difference-between-spf-and-upf/:

Currently, in the United States, the standards for UPF are voluntary.

This made me wonder: Does displaying the UPF value on a textile (or its description on a merchant's webpage) have any legal binding in the United States?

1 Answer 1


It is not binding in the sense that a contract term is binding and enforceable, but it has potential legal power. It possibly represents a factual claim, and factual claims in advertising cannot be deceptive. Since there is no legal standard (contrast with USDA standards for "organic"), the proof required to establish deceptiveness is less clear. For instance, for "organic" certification, the land may not have been treated with prohibited substances for at least 3 years, therefore 2 years is not good enough by that standard. AATCC Test Method 183 is not legally authoritative, so variation in the procedure is permissible. Still, if you cook up some cockamamie procedure and declare actual UPF 5 to be UPF 50, that would likely be found to be deceptive.

  • Got it, thanks very much for the clear explanation! I wonder how far from AATCC Test Method 183 can a UPF testing go without being considered deceptive by a court. Probably up to the judge's subjectivity. Jan 25, 2020 at 19:43

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