IES 2019 Annual Conference

Discomfort glare has been the intractable bugaboo of lighting for decades. Whether it’s interior or exterior lighting, we’ve all sensed that LEDs can be worse than conventional lighting. Why? This talk will address what has been learned about luminance distribution across luminaire apertures, how and why edges and SPD affect glare perception, and how glare metrics are being modified to be better predictors. This talk will include a demonstration of pairs of luminaires, developed through the IES DGONE Committee work, that have identical lumen output and candela distribution, yet produce very different glare responses. It will also reinforce why totally uniform light distributions may not be the answer.
This topic is a prominent issue for specifiers and manufacturers. How do we improve products so that LEDs are not automatically associated with discomfort glare? Yes, there are tradeoffs between efficacy and ideal light distribution. Is there a happy medium between stellar efficacy and visual comfort?
The work of the CIE Joint Technical Committee 7 will be addressed, an international effort to improve UGR as a predictive metric for discomfort glare. Also included will be the work of the IES DGONE Committee, focusing effort into glare metrics for outdoor applications. The presentation will also call upon the work performed at Pacific Northwest National Laboratory in examining high-efficacy industrial products, as well as an experimental investigation into how position in the visual field, source size, source SPD, and background luminance affect the glare response.