# 17-26-075

ultraviolet protection factor

UPF

FUVP

measurement of the protective quality of a fabric sample against solar ultraviolet radiation, determined by in-vitro testing

Note 1 to entry: For in-vitro testing the erythemal irradiance measured by a detector with the fabric sample under test in place is compared to the erythemal irradiance measured with no fabric present, where the source is typically a solar simulator. This is expressed as the quotient of the erythemal irradiance without fabric and the erythemal irradiance through fabric:

where ser(λ) is the erythema spectral weighting function, Eλ is the spectral irradiance, τ(λ) is the measured spectral transmittance of the item, and λ is the wavelength.

Note 2 to entry: The ultraviolet hazard spectral weighting function, SUV(λ), has been substituted for ser(λ) in special instances. If so used, the ultraviolet protection factor, FUVP, has to be noted as FUVP [S(λ)-weighted].

Note 3 to entry: The ultraviolet protection factor has unit one.

Note 4 to entry: This entry was numbered 17-1366 and 17-1377 in CIE S 017:2011.

Publication date: 2020-12