FBL has various meanings in the Architectural category. Discover the full forms, definitions, and usage contexts of FBL in Architectural.
A unit of measure for lumber equal to 1 inch thick by 12 inches wide by 12 inches long. Examples: 1" x 12" x 16' = 16 board feet, 2" x 12" x 16' = 32 board feet. Space in a window sash for a single pane of glass. Also, a pane of glass. A factor used in calculating luminance after a given period of time and under given conditions. It takes into account temperature and voltage variations, dirt accumulation on luminaire and lit surfaces, lamp depreciation, maintenance procedures and atmos.
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