UGR

UGR stands for "Unified Glare Rating." This is a method developed by the CIE (Commission Internationale de l’Éclairage) to provide a uniform way of specifying the glare from luminaires worldwide. The advantage of this new UGR rating is that it takes into account the glare from the entire lighting system as a whole, rather than just the luminance levels of individual luminaires. Glare is calculated from a uniformly defined observer position. The UGR reference value for this is specified in DIN EN 12464-1, where the following applies: The higher the UGR value, the more likely glare is to occur. UGR values can range from 10 (no glare) to 30 (noticeable physiological glare). For tasks requiring a high degree of detail, the UGR values should therefore be as low as possible. In addition, the so-called elevation angle—typically 65, 75, or 85 degrees—is often specified for luminance values less than 1,000 candelas per square meter (ratio of luminous intensity to area). This is the threshold angle above which the lamp once again has a luminance of 1,000 candelas per square meter in all directions. For workplace lighting, the following UGR values apply, among others:

• Technical Drawing: 16 UGR
• CAD Workstation: 19 UGR
• Traffic Zones and Copying: 19 UGR
• Writing, Reading, and Data Processing: 19 UGR
• Conference and meeting rooms: 19 UGR
• Reception: 22 UGR
• Archive: 25 UGR