UGR Values by International Commission on Illumination (CIE)

What are the standards for glare control for office lighting?

Standards for glare control may vary between countries and regions, as they are often based on local regulations, standards, culture and personal needs. In some countries and regions, glare control standards may be more stringent, because people in these areas have higher requirements for visual comfort, and they also pay more attention to energy saving and environmental protection. With the increase of globalization and international exchanges, more and more countries and regions have begun to adopt more stringent glare control standards to improve lighting quality and visual comfort.

The standards for glare control mainly involve the following aspects:

Unified Glare Rating (UGR)

Glare index is an indicator for evaluating indoor glare conditions, usually based on the UGR value recommended by the International Commission on Illumination (CIE) as the standard. According to different usage scenarios and requirements, the UGR value will have different limits. For example, the UGR in offices, classrooms and other places is generally required to be lower than 19(UGR<19). For elderly activity venues, it is recommended that the UGR value be controlled below 16 (UGR<16).

2. Threshold increment (TI)

In road lighting design, threshold increments are used to evaluate disabling glare. According to CJJ45 urban road lighting design specifications, the TI limit for expressways, trunk roads, and secondary trunk roads is 10%, and the TI limit for branch roads is 15%.

3. Glare index (GR)

In the lighting design of sports venues, glare index is an important evaluation index. The  value of Class I sports venue lighting should not be greater than 35. The GR value of sports building lighting above level II should not be greater than 30.

4. Shading angle

The shading angle refers to the angle between the line connecting the outermost edge of the light source and the edge of the light outlet of the lamp and the horizontal line passing through the center of the light source. An appropriate shading angle can reduce glare. The larger the shading angle, the smaller the glare. Lamps for normal use should have at least a shading angle of 10°~15°,while in environments with high lighting quality requirements, the shading angle of lamps should reach 30°~45°.

5. Direct light angle

Control the direct angle of light within 30°, and also control the reflected light within 30° to reduce glare.

The standards for glare control involve many aspects, including glare index, threshold increment, glare index, shading angle and direct light angle. These standards are developed to ensure people's visual comfort when working or doing activities indoors, and to reduce eye fatigue and discomfort.