The standard specifies test methods for calibrating narrowband and wideband UV radiometers using sub-light spectrum radiometers. The standard applies to calibrating UV measuring instruments using scanning type or linear diode array Light spectrum radiometers as reference instruments. It covers the calibrating of multiple Light sources such as natural sunlight, Xenon-arc lamps, metal halide lamps, and defines Wavelength ranges in the UV and visible regions. The standard specifically states that appropriate precautions should be taken during the calibrating process, especially for radiometers with Light spectrum Response below 320 nm. Users need to follow relevant safety specifications and be aware of applicable regulatory restrictions.