Used to calculate or project lighting system performance after a given period of time under certain conditions; takes into account variations in temperature and voltage, dirt, lamp depreciation and maintenance. Also called "maintenance factor."
A factor used in calculating the illuminance after a given period of time and under given conditions. It takes into account temperature and voltage variations, lamp depreciation (of electric luminaries), dirt accumulation on luminaire and room surfaces, maintenance procedures and atmosphere conditions. Formerly called maintenance factor.
The product of all factors that contribute to lowering the illumination level including reflector degradation, dirt, lamp depreciation over time, voltage fluctuations, etc.
Factors that allow for a lighting system's operation at less than initial conditions. These factors are used to calculate maintained light levels. LLFs are divided into two categories, recoverable and non-recoverable. Examples are lamp lumen depreciation and luminaire surface depreciation.
A measure of the light output near the end of the lamp's life compared to the initial lumen output expressed as percentage of the initial lumen output. It takes into account the decrease of lumen output as the lamp ages, the amount of dirt in the environment and how often the fixture is cleaned and the decrease in lamp output as the ballast ages. It takes into account the Lamp Lumen Depreciation Factor, the Luminaire Dirt Depreciation Factor and the ballast factor.
A factor used in calculating the level of illumination that takes into account such factors as dirt accumulation on luminaire and room surfaces, lamp depreciation, maintenance procedures and atmosphere conditions.
