CEILING LUMINANCE RATIOS FOR LINEAR FLUORESCENT INDIRECT LUMINAIRES

This paper presents a simple means for determining the ceiling luminan ce ratio of a lighting system using linear fluorescent indirect lumina ires. This is accomplished by referencing the ratio of two luminaire i ntensities (I-R): the intensity of the luminaire at zenith (I-90,I-180 ), and intensity in the direction at mid-point between two rows of lum inaires (I-90,I-0). This geometry determines the Luminaire Spacing to Luminaire-to-Ceiling-Distance Ratio. The analysis is based upon comput er simulations using a series of photometries of linear fluorescent in direct luminaires in typical application situations. The analysis take s into account the interreflected light component. The results are pre sented in an easy-to-use chart format. This chart can be a useful tool that allows lighting designers to quickly evaluate ceiling luminance ratios.