Glare index

Glare index

A value for predicting the presence of glare as a result of daylight entering an area. The glare index is affected by the size and relative position of fenestration, orientation to the sun, sky luminance, and interior luminance. The glare index is similar to the index of sensation and the discomfort glare rating, which are used for electric-lighting applications.
References in periodicals archive ?
The Illuminating Engineering Society of North America (IESNA) recommended contrast ratio limits and Hopkinson Cornell Large Source Glare Index (DGI) (1) are used as a basis for evaluation.
The Hopkinson-Cornell large-source glare index (daylight glare index or DGI) is a metric commonly used to evaluate discomfort glare for large-area sources of glare such as windows [Hopkinson and Bradley, 1960; IES 1962].
To address this problem, a weighted daylight glare index ([DGI.
These luminance maps were analyzed using a weighted Hopkinson Cornell Daylight Glare Index (DGI) and the IESNA recommended contrast ratio limits to quantify how innovative interior and exterior shading systems compared to conventional systems under real sun and sky conditions over a solstice-to-solstice test interval.
In the 1950s the IES Glare Index System was developed to reduce the possibility of visual discomfort through over-bright luminaires when seen in the normal field of view (FOV).
We obtained values of daylight glare index (DGI) from luminance maps by means of high dynamic range images (HDRI) [Inanici and Galvin 2004].
Several studies evaluated the relationship between shading controls, glare problems, and energy usages (Wienold 2007; Chan and Tzempelikos 2013; Tzempelikos and Shen 2013) while others used the glare index as an indicator to control shading devices (Oh, Lee et al.
On the other hand, visual performance studies (Blackwell, 1959; Boyce, 1973; Rea and Ouelette, 1991) and visual comfort metrics such as Daylight Glare Index (DGI) (Hopkinson, 1972; Chauvel and others, 1982) and Daylight Glare Probability (DGP) (Wienold and Christoffersen, 2006) establish a relationship between luminance, comfort, and visibility.