The average luminance of luminaires is important regarding the lighting of VDU workstations (q.v. Chapter 188.8.131.52 Office). The average luminance of a luminaire’s light-emitting surfaces must be measured and/or calculated in intervals of 15° starting at 0° in the C levels as well as for the beam angles γ = 65°, 75° and 85° according to EN 12464-1. Generally, this data is provided by the luminaire manufacturer.
Luminance of luminaires
The European standard EN 13032-1 "Light and lighting - Measurement and presentation of photometric data of lamps and luminaires – Part 1: Measurement" contains the measuring instruction for average luminance values.
On-site measuring of the actual state of the average luminaire luminance is only possible with appropriate measuring effort, e.g. using image-resolution luminance measuring instruments (CCD camera).