The BUG rating system has been created to replace the cutoff system of classifying outdoor luminaires. B (backlight) U (uplight) G (glare) are all scored on a scale of 0-5, with 5 being the highest amount of maximum zonal lumens emitted from the fixture in a direction and 0 being the lowest. Backlight consists of the amount of light in the BL, BM, BH and BVH zones, which is any light that is shining in the opposite direction of the area intended to be lit. Uplight is measured in UL and UH, which cause skyglow and wasted energy respectively. Glare is a measure of the FH, FVH, BH and BVH zones, which cause discomfort and disability glare.
Area Lighting, Backlight-Uplight-Glare (BUG) Rating System, BUG, IDA, Light Pollution, Street Lighting