DISCOMFORT GLARE OF NON-UNIFORM LUMINAIRES - A LITERATURE REVIEW (PO09, Pages 247-256)

For indoor lighting, the established measure for discomfort glare is the Unified Glare Rating (UGR), which assumes that the source area may be characterized by the average luminance. With the introduction of LEDs in general lighting, many new luminaire types have become available, some of which with a highly non-uniform luminance distribution. 60 papers were reviewed, of which the majority is from a more recent date (2012-2016). Many studies show that for the same average luminance, there is a significant difference in discomfort glare experience between uniform and non-uniform luminaires, and subsequently imply that UGR is not always a reliable glare measure of these highly non-uniform luminaires, characterized by high luminance contrasts and high local peak luminance in the exit windows. In this paper, all proposed alternatives to predict discomfort glare are discussed, with a focus on proposals that are easy to implement as limited modifications of the UGR.