UGR Definition

UGR is the abbreviation of Unified Glare Rating, which means unified glare value. It is a psychological parameter to measure the subjective response of the light from lighting devices to the uncomfortable feeling of human eyes in indoor visual environment. Its value can be calculated by the CIE Unified Glare Rating formula according to the specified calculation conditions. Different UGR values have obvious differences in lighting effects and bring about great visual and psychological differences. Specific use sites also differ, as follows.

1. UGR = 13, because just feel the glare, light curtain reflection less, space ceiling is darker, giving a feeling of eerie; generally used in the machine room and monitoring room.

2. 16 < UGR < 19, just right, is the dividing line between comfort and discomfort, limited control of glare, light curtain reflection, is the first choice for comfortable office space; generally used in ordinary, high-end offices, library reading rooms, hospitals, school buildings, etc.

3. UGR>19, because it is just uncomfortable, lighting space is vibrant, but glare and light curtain reflection attract people's attention; generally used in commercial building lighting, business hall, etc.

UGR test principle

The original industrial and civil lighting design standards specify that the direct glare of indoor general lighting is limited by the brightness limitation curve. This limiting method is only for the glare of a single lamp, and cannot represent the total glare effect of all lamps in the room. Therefore, CIE has proposed the Uniform Glare Rating (UGR) calculation formula based on a combination of glare calculation formulas from various countries. It is applicable to the general lighting design of simple cubic rooms. Luminaires are evenly arranged and equally spaced. The lamps are double symmetrical. The observation position is generally at the midpoint of the vertical and horizontal walls, with the line of sight level with the front.

UGR test factors

UGR test results is a system engineering, involving the size of the space, background brightness, the brightness of each lamp in the direction of the observer, each lamp luminous part of the three-dimensional angle formed on the observer's eyes, the position of each single lamp indicators, these factors interact and influence each other, and ultimately affect the UGR test value.

UGR control method

1. avoid installing lamps in disturbed areas.

2. using low gloss surface decoration materials, such as UGR diffusers.

3. limiting the brightness of the luminaire.