Spectral Energy Distributions and Aging Characteristics of Fluorescent Sunlamps and Blacklights

Abstract

The spectral energy distributions of commercially produced 20-W fluorescent sunlamps and blacklights designated for use in the revision of the American Society of Testing and Materials (ASTM) Recommended Practice for Exposure of Plastics to Fluorescent Sunlamp (D 1501-71), were measured between 250 and 600 nm at 3-nm intervals. Two types of blacklights with the same designation (F20T12B1), but with different emission characteristics, are manufactured. The decrease in emission intensity with hours of use varies with type and source of lamps. The best simulation of sunlight in the ultraviolet region below 360 nm is given by the combination of one sunlamp with one of each type of blacklight.