UGR (Unified Glare Rating) is a method of calculating glare from luminaires, light through windows and bright light sources.
The UGR rating helps to determine how likely a luminaire is to cause discomfort to those around it. For example the discomfort that a LED Panel will cause the work force within an office. This classification ranges from 5 to 40, with low numbers indicating low glare.
Glare can be a common problem in workplaces. Inappropriate luminaires cause excessive brightness to be “bounced off” reflective surfaces, such as computer screens, whiteboards etc. This can cause disruption for the occupants of offices, in terms of headaches & eye trouble, which can then lead to employee absences.
UGR is calculated by using an equation which takes into account a number of factors that may contribute to glare caused by a luminaire, such as the angle of the luminaire, the likelihood of glare and the luminance value (lumen output). The equation that is used to calculate the UGR is: