Standard Practice for Performing Accelerated Outdoor Weathering of Nonmetallic Materials Using Concentrated Natural Sunlight Durability, Exposure, Fresnel-reflector, Weathering, Accelerated aging/testing-building materials, Accelerated weathering, Durability-paints/related materials, Exposure tests-atmospheric, Fresnel-reflector system, Mirrors, Nonmetallic materials, Outdoor weathering, Qualitative analysis/measurement, Spectral data, Sunlight/monochromatic light exposure, Ultraviolet (UV) analysis-nonmetallic materials