Fire-retardant-treated products for exterior applications must be subjected to actual or accelerated weathering prior to fire testing. Sometimes referred to as the “800-inch rain test,” the ASTM D2898 test has two methods to simulate weathering. Method A subjects the materials to 12 one-week condition cycles of 96 hours of water exposure and 72 hours of drying at 140 degrees F, the equivalent of 800 inches of rainfall over 12 weeks. Method B subjects materials to 1,000 hours of 24-hour exposures featuring four hours of wetting, four hours of drying and eight hours of resting, with drying time at 150 degrees F with continuous UV exposure.