UGR or glare rate of discomfort what is it? How to improve it?

 What is the UGR or glare rate of discomfort? Here we explain all the concepts to master on the subject.

WHAT IS GLARE?


Glare is a feeling of discomfort caused by the presence of bright flashes of light in the field of vision. This is particularly the case when we look at a bulb directly or the reflection of the sun on the surface of the water.

UGR rate of comfort

the reflection of the sun on the surface of the water.
There are two kinds of glare: disruptive glare and uncomfortable glare. The first consists of the appearance of a luminous veil causing a blurred vision and a decrease in sensitivity to contrasts, which disappears with the cause of glare. A good example of disruptive glare is caused by the long-range lights of vehicles that pass us when we drive at night. The second, uncomfortable glare, consists of a sensation of visual discomfort produced by a too intense luminosity, causing certain visual fatigue. The latter is the most common cause of dazzle indoors, on which the UGR is based.
Glare can occur in two ways: by direct observation of a light source (when looking directly at a fixture, for example). Or by indirect observation (egg, the reflection of the light source); as may be the case when we observe the reflection of a bulb on a shiny surface.

WHAT MEASURES THE UGR?

The UGR or rate of discomfort glare (Unified Glare Rating English), created by the International Commission on Illumination (CIE) in 1995, quantifies in interior lighting discomfort glare, depending on the position of the observer and the direction in which he looks. The NF-EN 12464-1 standard on workplace lighting sets an acceptable UGR threshold. The higher the rate of the glare of discomfort (UGR value), the greater the glare sensation (lower quality). The maximum recommended UGR value varies according to the activity performed.
The nominative UGR values vary from 10 to 30, 16 is equivalent to a noticeable glare, and 28 to a dullness that is difficult to tolerate. UGR reference values are usually: 16, 19, 22, 25 and 28.
This difference of 3 points between each reference value is explained by the fact that the variation is not perceptible to the naked eye in a unitary manner.

WHAT IS LIGHT COMFORT?

Studies have shown that the human eye only perceives luminance between 3 and 100,000 lux. Note that for a comfortable activity, the luminance must be between 100 and 1000 lux. By lighting comfort, reference is made to the general impression of visual comfort felt during the practice of an activity. Such comfort promotes concentration, creativity, and intensity among other factors.


It is estimated that there is discomfort in lighting when the brightness is too bright, the lighting is direct or flashing and the color rendering index (ICR) is too low or the contrasts are too marked.
UGR or glare rate of comfort

How to identify environments conducive to glare discomfort (high UGR)?
Glare is usually due to excessive light or direct exposure. It can be caused directly by fixtures, or by reflections (windows, screens or other reflective elements). Most often, glare is accompanied by a sensation of visual discomfort or even headaches. In addition, there is a marked decrease in concentration and work efficiency.

THE MAIN VARIABLES THAT INFLUENCE THE UGR ARE:

·        The technical characteristics and the design of the luminaires
·        The luminous index of adjacent surfaces (screens, windows, tables and other glossy surfaces, mirrors, etc.)

·        The position of the observer vis-à-vis the luminaire (direct luminous angle according to the height of his gaze and the distance separating it from the lamp).

HOW TO REDUCE UGR LEVEL AND ENHANCE LIGHTING COMFORT?

Today, there are a large number of products specially designed to guarantee a low UGR index: diffusers (opaque), luminaires, etc. designed to fight against glare without compromising light output.
·        LED panel with micro-prismatic diffuser UGR <19:  LED panels are a real advance over older fluorescent neon installations that emit light directly using reflective elements. The asperities of the micro-prismatic diffuser allow an even more homogeneous diffusion of the light, thus canceling any risk of dazzling. In addition, our LED panels are equipped with a LiFud driver that limits blinking, and their LED panel displays an IRC index of 80-85. A perfect option for use in school, office or hospital.
·        Anti-glare linear suspensions (UGR <18): the ideal solution for illuminating with suspensions without dazzling. The light source of this suspension is deeper than usual, which allows it to emit an intense light and pleasant at a time, without risk of glare. These luminaires are used in particular above office desks/shop counters, at the hotel reception, in libraries/reading rooms, an architect or drawing studios, and more generally in all workplaces to be lit continuously all day long.
·        Dichroic bulbs with anti-glare support: anti-glare supports are systems with a cover that "hide" the light source without affecting its intensity or performance (the light source is visible only when the light source is visible). We are just below). Anti-glare brackets (UGR <16) are perfect for lighting museums, showrooms, libraries, study halls, etc. because they create an enveloping, homogeneous and pleasant lighting.
·        glare grid for dichroic bulbs and rail spots: it is possible to place a grid "honeycomb" compatible with any standard media on your bulbs and dichroic your spots on the rail. This eliminates any risk of glare without reducing the lighting capacity of your luminaire.
 Also, read about Commercial track lighting



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