What is UGR and GR?

Lighting is an area that involves many technical details to ensure visual comfort and efficiency. One of the factors that most contributes to good lighting is glare, which can be expressed by the UGR and GR indexes.

What is UGR?

Unified Glare Rating - measures the effect of psychological glare in interior spaces. Glare is the discomfort or impairment of vision caused by excessive brightness or contrast in the visual field.

The EN 12464-1 standard determines the maximum permissible values of UGR in the interior spaces of various workplaces. Some definitions of the maximum level of UGR, according to this standard:

• Circulation areas and staircases — UGR <25

• Waiting rooms, receptions and shops — UGR <22

• Classrooms, offices, meeting and conference rooms — UGR <19

• Precision work areas — UGR <16

It should be noted that, in addition to the luminance of the luminaires, the UGR value depends on the position of the observer, the direction of gaze and the luminance of the environment./b>.

What is GR?

Glare Rating refers to the level of glare (like UGR) but is more often used in outdoor lighting contexts, such as roads and public areas.

GR measures the impact of glare in outdoor environments, where there can be a larger variety of light sources and less control over them.

Importance of UGR and GR

The measurement and control of UGR and GR indexes influences various lighting issues, such as:

• Visual comfort: Rooms with lower UGR or GR generally offer greater visual comfort;

• Safety: On roads and in public places, glare values should be low and controlled in order to prevent accidents;

• Productivity: In places of study and work, low levels of UGR contribute favourably to greater productivity;

• Eye Health: Prolonged glare can cause visual fatigue and other eye health problems.

The UGR and GR indices are fundamental in assessing and controlling glare in different environments. Understanding and applying these concepts is crucial to creating well-lit, comfortable, safe and efficient spaces.