Encyclopedia of Color Science and Technology

Living Edition
| Editors: Ronnier Luo

Lumen Depreciation

  • Wout van Bommel
Living reference work entry
DOI: https://doi.org/10.1007/978-3-642-27851-8_136-2

Synonyms

Definition

Light losses during the use of a lighting installation, caused by the decrease of the luminous flux of lamps, the dirt accumulation on and loss of reflectivity and or transparency of luminaires, and dirt accumulation on or discoloration of room surfaces (in interiors).

Lamp Lumen Depreciation

The light output of virtually all lamp types declines gradually during operation. The causes of light output depreciation are numerous. With incandescent lamps, it is especially the blackening of the bulb – caused by evaporation of the filament. Discharge lamps also suffer from blackening, in this case due to scattering of the electrode material, which settles on the wall of the discharge tube. With fluorescent lamps, high-pressure mercury lamps, and solid state, LED, and OLED light sources with a fluorescent coating, the major cause of light output depreciation is a gradual exhaustion of the fluorescent powder, which slowly loses its effectiveness.

Because...

Keywords

Dirt Accumulation Luminous Flux Maintenance Operation Light Loss Lamp Manufacturer 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.
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Copyright information

© Springer Science+Business Media New York 2013

Authors and Affiliations

  1. 1.van Bommel Lighting ConsultantNuenenThe Netherlands