This International Standard specifies exposure conditions for paint coatings exposed to artificial weathering in apparatus including fluorescent UV lamps and condensation or water spray. The effects of weathering are evaluated separately by comparative testing of chosen parameters. NOTE The ultraviolet light produced by fluorescent lamps simulates only part of the UV region of natural sunlight and, consequently, the test pieces are subjected to a small but destructive portion of the spectrum. Due to the lack of visible and infra-red energy in the light from such UV lamps compared to sunlight, the test pieces are not heated above the temperature of the surrounding air in the way in which they would be in practical use.