12.1.2.3-9 Glare

Glare should not interfere with the readability of displays, labels, or indicators.

Additional Information: Glare increases the probability that an individual will misread a display or will fail to notice displayed information. Glare can also produce discomfort. Direct sources of glare include

 

light emitted from luminaires, indicators, and displays. Indirect sources of glare include reflected light from all surfaces (e.g., paint, metal, and glass). The surface of a visual display device screen should reduce reflections. Positioning of visual display devices relative to light source affects glare as can the use of a shield or filter on the visual display device or light source. If glare reduction or contrast enhancement techniques are used, they should not violate the requirements of luminance, contrast, resolution, and other specifications for the visual display device itself in its installed configuration, as stated in Section 11.3.1. In cases where more detailed analysis of glare is required, the unified glare rating (UGR) should be employed. The UGR is a measure of the overall glare in an environment, considering both disability and discomfort glare. The UGR is the common logarithm of the sum of the luminances from all visible light sources, divided by the background luminance, with corrections for the solid angle of the light source and the distance from the line of sight of the observer. In general, the lighting system should achieve a maximum UGR of 19 or less for all work positions in the control room. Methods to calculate and evaluate the UGR may be found in ISO 8995-1 (2002). A tabular method of calculation and presentation of UGR data may be found in CIE 190 (2010). 27 0700, 5908, 11064-6

 

© ISO. This material is excerpted from ISO 11064-6: 2005 with permission of ANSI on behalf of ISO. All rights reserved.