Illumination Technology

Study Notes

Lighting Design and Illumination

DLOR stands for Downward Light Output Ratio, which is the ratio of lumens emitted downward by a lighting fixture to the total lumens produced by the luminaire.
The purpose of the maintenance factor in lighting design is to account for the reduction in illumination over time due to lamp depreciation and dirt accumulation.
The coefficient of utilization (CU) is the ratio of the lumens received on the task surface to the total lumens emitted by the luminaire; it takes into account the efficiency of the luminaire and the room's reflectances.
ULOR stands for Upward Light Output Ratio, which is the ratio of lumens emitted upward by a lighting fixture to the total lumens produced by the luminaire.
The space to mounting height ratio is used to determine the number of luminaires required for a given space, and is calculated by dividing the mounting height of the luminaire by the spacing between luminaires.
The coefficients of utilisation are affected by factors such as room surface reflectances, luminaire efficiency, and luminaire distribution.
Lamp lumen output is determined by considering the effects of voltage and temperature variations on the lamp's performance; this is typically done using manufacturer-published data or by testing the lamps.
The Indian standard recommends specific illumination levels for various areas, including residential, commercial, and industrial spaces.
The space to mounting height ratio is significant in lighting design because it determines the number of luminaires required to achieve a desired illumination level, and affects the overall efficiency and uniformity of the lighting system.
The selection of utilization factor, reflection factor, and maintenance factor is crucial in interior lighting design because it directly impacts the calculation of the required number of luminaires, and ultimately affects the energy efficiency and overall performance of the lighting system.