Glare is defined by the International Commission on Illumination (CIE) as a “condition of vision in which there is discomfort or a reduction in the ability to see details or objects, caused by an unsuitable distribution or range of luminance, or by extreme contrasts” [CIE 2019a].

What is the Unified Glare Rating? The Unified Glare Rating (UGR) predicts the glare caused by an electric lighting system along a psychometric scale of discomfort. In simpler words, UGR predicts the amount of discomfort-causing glare produced by a lighting installation for a fixed set of conditions. Discomfort glare

Metrics: CIE Glare Index (CGI) Scale: > 28 Intolerable < 13 Barely Perceptible • Published by Einhorn in 1969 and adopted by the CIE. • Calculations require both direct and diffuse illuminances. • For luminaire sources of glare.

Rather, the current state-of-the-art for assessing discomfort glare is the use of subjective rating scales, such as the De Boer (1967) scale, commonly used to assess vehicular headlamp glare and glare from other outdoor lighting. The De Boer (1967) scale uses a nine-point scale with odd-numbered values having the following equivalencies:

The UGR scale has practical ranges from 10 to 30, with a higher value indicating greater visual discomfort and a lower value indicating little discomfort glare. A UGR of 19 is considered the upper level of acceptable discomfort glare when related to the Hopkinson’s ratings scale2, a narrative ratings hierarchy

Glare rating is calculated for each point on grid based on the veiling luminance produced on the eye by the luminaires and the environment. When Glare Rating is specified, grids are created for each observer position that duplicate the specified horizontal illuminance grid.

Feb 14, 2023 · Universal glare rating, or UGR, is the measurement used to calculate glare from light fixtures or luminaires. It is a parameter or value that gives information about the extent of the psychological glare of a luminaire in an indoor space. A scale of 10-40 is used to describe UGR.

Unified Glare Rating (UGR) is a measure of potential discomfort glare experienced by an occupant in interior lighting spaces. UGR incorporates data from electric sources within an interior environment and assigns a value which represents the calculated glare rating.

Jul 4, 2024 · The Unified Glare Rating (UGR) is a key metric for evaluating discomfort glare in indoor lighting environments, focusing on the direct light component. Recently, it has gained importance for obtaining WELL certification points.

One of the most adopted glare scales is the 4-point Osterhaus’ scale – imperceptible/noticeable/disturbing/intolerable –, although scales that used modified versions of the 5 labels from the 9-point De Boer’s scale – unbearable/disturbing/just admissible/satisfactory/unnoticeable – are also common.