A variety of values are important when it comes to light sources. Think of IP values, CRI values, Kelvin values and brightness in Lumen. In this article we are talking about UGR values. In short, the UGR value has to do with glare. Everyone experiences this from time to time. Have you, for example, ever had to deal with a bright sun that impeded your vision? Or has anyone ever been shining a flashlight in your face? UGR has everything to do with this. UGR stands for Unified Glare Rating. This value indicates the extent to which there is glare at a measured position. An URG value can never be directly linked to a light source. The degree of glare depends on the position and viewing angle of the user and other factors such as ambient light and reflective light.
It is important to realise the right UGR value to avoid headaches and other discomforts caused by glare. The ideal UGR value is different for every room and every place in the room. For example, in places where good visibility is essential, a lower UGR value should be achieved. However, this should not be at the expense of the light output. The light should be bright enough to be able to carry out work or activities without glare.
Glare occurs when the retina is exposed to a higher level of light than it has been adjusted to. Think, for example, of when you are in the car in the evening, and a car with a high beam meets you. In this case, the ambient light intensity is low. The high brightness of the headlights of the opposing vehicle makes it difficult for you to see the road. Glare can lead to discomfort, but also to visual impairment. Because the human eye is not designed to process excessive amounts of light, the light will be scattered when it's intensity is too high. As a result, the retina does not capture the image that it would receive at a lower brightness level. The scattered light creates a kind of shroud. This reduces the amount of contrast that can be seen.
In the case of glare, a distinction can be made between direct glare and indirect glare. Direct glare occurs when a person is looking at a light source. Indirect glare occurs when a person sees the light from a light source in the reflection of another surface. Think of light reflection on a TV or computer screen. The surfaces of TVs and computers are usually very shiny and reflect a lot of light.
Direct glare can usually be prevented by not looking in the direction of a light source. However, you are then vulnerable to the light that reflects off surfaces on the opposite side (indirect glare).
Measuring the UGR value at a certain location is not as easy as measuring the light intensity. There are a number of variables that influence the glare value. We can distinguish 4 factors:
Type of room
The measuring point
The reflection of light
The light source
The ideal UGR value varies according to the type of room. In a precision working environment, it is important that there is no glare. Think, for example, of an operating room or a drawing room. For this purpose, it is important that the person carrying out the work has optimum visibility in order to carry out their tasks correctly. Glare can cause reduced visibility. The size of the room also plays a role. If the ceiling of the room is higher, the UGR value will be lower at eye level and vice versa. It also applies that if a room is larger, there is less glare. A higher UGR value is often found in rooms that do not have a specific or important function and where little time is spent. Think, for example, of a corridor or a storage area. Here it is simply less important to have sufficient light.
The UGR value may vary from place to place in a room. The UGR value also depends on the viewing angle of the observer. The normal posture of a person in the room must therefore be taken into account. If you often have to look upwards, the UGR value is automatically more important than in a room where you only have to look downwards. Of course, the areas that are the most frequently looked at should be taken into account. If these reflect too much, glare could still occur.
All surfaces reflect light to varying degrees. For example, light reflects more on a light surface than on a dark surface. A glossy surface also reflects more than a matt surface. Make sure to always consider reflective surfaces when installing lighting.
The light source affects the UGR value. The more light the light source produces, the higher the risk of glare. Often manufacturers of light sources give these products an URG value. This value applies to a specific room with specific surface reflectance values. In rooms where glare should be avoided as much as possible, it is advisable to use several light sources with a lower brightness. This way, the light is more evenly distributed.
At home, you can decide for yourself how you want to adjust your light. In working environments it is important to know how high the UGR should maximally be. The NEN-EN 12464-1 standard sets out the guidelines for lighting on the work floor. Below are the maximum recommended UGR values for lights in certain rooms stated.
|Type of room||UGR (of the light source)||Visibility|
|Drawing room (high precision)||<16||Not visible|
|Counters & fine industry||<22||Acceptable|
|Warehouses, staircases, elevators, and factories||<25||Unpleasant|
|Walkways & corridors (lighting not important)||<28||Unacceptable|
When illuminating rooms, it is recommended to test before you install the lighting permanently. This can be done by placing the lighting in the right place and ensuring that this does not cause any inconvenience.
The LED Panels of Ledpanelwholesale comply with the UGR <19 value. Our LED Panels are therefore suitable for use in offices and in workspaces. By connecting a flicker-free driver to the LED Panels, you also reduce flickering of the light. You can also choose to connect a dimmable driver. This allows you to adjust the brightness to the desired level.
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