Variations in Illuminance Caused by Shadow under Task Ambient Lighting

Considering the Arrangement and Luminous Flux of Ambient Light

Abstract

We examined the characteristics of shadows created by task ambient lighting mounted on a ceiling on a work surface (a desk) for various combinations of lighting arrangements and luminous fluxes. Shadowing in work areas has become of greater concern with the decrease in illuminance on work surfaces due to the obstructions created by modern office designs (e. g., room partitions).
We found that when the arrangement and flux produce an illuminance uniformity ratio of greater than 0.7, the maximum shadow factor is less than 0.6, and the areas in shadow are less than 15% of the total area. Application of this principle will enable the design of more comfortable and efficient offices.