UGR stands for United Glare Rating. The UGR value determines the extent to which lighting is stressful through glare or light pollution in a specific room. An average UGR value is between 15 and 30. The higher the UGR value, the more stressful the lighting is.
How is the UGR value determined?
Before we tell you how the UGR value is determined, some information about glare is necessary. There are two types of glare that can occur with light sources: direct glare and indirect glare. In the case of direct glare, a lamp emits light directly into a person’s eye, causing glare. In indirect glare, light is reflected into the person’s eyes, such as through a reflective object.
Thus, both types of glare must be taken into account when determining the UGR value. It is also important to consider the size of the room and, for example, the color on the wall. The color white reflects quickly and so a room with white walls will cause glare more quickly. Thus, there are other diverse factors that are taken into account. The combination of these factors determines what UGR value a room needs.
UGR value per room
There are a number of standard UGR values which have been established according to the guidelines of the NEN-EN. Below we give some examples:
| Space | UGR value |
| Office, workplace | UGR 19 or lower |
| Corridor | UGR 28 or lower |
| Stairs or elevator | UGR 25 or lower |
| Entrance area | UGR 22 or lower |
| Drawing space | UGR 16 or lower |
What should you look for in the UGR value?
Because of safety at, mainly, workplaces, guidelines have been established according to the NEN-EN 12464-1 standard. In this, maximum UGR values per room are determined. Read up well before setting up lighting. This is only applicable in rooms where work is done: in homes it is not necessary. In addition, it is important to look at the necessary UGR value for each separate room rather than for each building. It is therefore essential to take the UGR value into account when (commissioning) a lighting plan.
LED panels with proper UGR value
LED panels often have a UGR of 16 or higher. LED panels from Ocab can achieve the office standard of UGR <19 by adding the right optics. A prismatic optic that prevents looking directly into the light source is often used for this purpose. This gives a calmer light image in the room.