1. Determining the luminaire height above the observer’s eye for sitting H = h – p – 1,2 m and for standing persons H = h – p – 1,7 m. Example: Room height h = 3,0 m, ceiling-mounted luminaires (p = 0 m), for sitting persons H = 1,8 m.
Application of UGR tables
2. The multiple of the luminaire height above the observer’s eye is determined L = 14 m /1,8 m = 7,8 H and B = 7,5 m /1,8 m = 4,2 H using the room dimensions (example: room length L = 14,0 m, room width B = 7,5 m).
3. The luminaires are mounted parallel to the longer room side (see sketch 1). UGR values can be gathered from the luminaire-specific UGR table for the applicable reflectance values of ceiling, walls and floor (in the example 0,7, 0,5, 0,2) according to the following reading rule 1 (see also table) with interim values to be interpolated as necessary:
Table 3.6
The values are highlighted with |..| in table
4. In some cases, the UGR values must be corrected regarding lamp luminous flux or other luminaire data.
Sketch 1
If the lamp/luminaire axis was oriented parallel to the shorter room side, the UGR values from the luminaire-specific UGR table would have to be gathered according to the following reading rule 2:
Table 3.7
The values are underlined in table.
Sketch 2