In order to examine UGR values, existing installation data must be compared to the UGR tables documented by the luminaire manufacturer, for the purpose of which all fundamental assumptions of the values in the tables must be compared to the actual installation. This particularly concerns reflectance values of room surfaces, luminance distribution of luminaires, luminaire arrangement and distance/height ratios of the luminaire arrangement, viewing direct and – where required – corrections in table values due to deviating lamp or luminaire data (see chapter , section UGR).
For measurement examinations of the UGR values in an implemented installation, it is necessary to determine
average luminance of the luminaires,
solid angles as a measure for the size of the glare light sources (luminaires) and
luminaire positioning relating to the position of the observer and viewing angle, all from the observer’s position.
These parameters can be calculated using image-resolution luminance measuring instruments and corresponding goniometers, on the basis of which it is then possible to calculate UGR values using suitable software.
The measurement of glare situations and the calculation of UGR values is only made possible using image resolution luminance measuring technology.