Lighting Light-Loss Factor (Maintained/Initial)
Light-loss factor = the product of the IES recovery factors (lamp lumen depreciation, luminaire/room dirt, ballast, burnout), and maintained lumens = initial x LLF. LLD 0.85 x LDD 0.90 x BF 0.95 = 0.727; a 4,000 lm fixture holds 2,908 maintained. The IES tables and maintenance schedule govern.
Formula and source
LLF = product of the entered recovery factors (LLD, LDD, BF, LBO, RSDD, temp/voltage/tilt); maintained_lm = initial_lm x LLF.
The IES light-loss-factor (recovery-factor) method, by name.
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