Cavities, Coefficients, and Direct Ratios

Abstract

A critical examination of the Zonal-Cavity coefficient concept identifies misconceptions that are widely held with regard to the direct ratio. The significance of independent parameters other than luminaire spacing-to-mounting height ratio are investigated for the direct ratio weighting factors (zonal multipliers). These include room length-to-width ratio and luminaire-to-wall spacing. It is shown that the presently neglected luminaire-to-wall ratio is of equal or greater significance than the luminaire mounting height parameter now used.