Validated UV-C bidirectional reflectance distribution function measurements with a spectrophotometer directional reflectance module

The efficacy and safety of UV disinfection systems depend on the radiant flux throughout the space being disinfected, which in turn depends on the directional reflectance of materials located within the space. Little publicly available data exists on the directional reflectance of common materials in the germicidal UV spectral range, 220–280 nm. We present methods to validate directional reflectance (bidirectional reflectance distribution function) measurements performed with a spectrophotometer and provide measurement results for materials commonly found in public spaces. The data presented may lead to improved models of UV disinfection efficacy and safety, and the methods described will enable other researchers to readily collect traceable UV directional reflectance data.