Illuminance in the immediate surrounding area

The illuminance in the immediate surrounding area is dependent on the illuminance in the visual task area and should create a balanced luminance in the field of vision.

Strong localised changes in illuminance in the area surrounding the working area can lead to visual overstress and discomfort. The illuminance in the immediate surrounding area can be lower than the illuminance in the visual task area, however, it cannot undercut the values specified in table.

In addition to the illuminance in the visual task area, the lighting in the entire room must create a suitable adaptation luminance distribution (see also section "1.2.6.4 Background lighting").

The illuminance of the immediate surrounding area and the background contributes significantly to a balanced luminance distribution in the field of vision. This also means that the minimum width of 0,5 m for this immediate surrounding area is only sufficient to avoid pronounced localised changes in illuminance in the area surrounding the visual task area and thus visual overstress and discomfort in few cases (size of immediate surrounding area see fig.).

In principle, the illuminance in the immediate surrounding area can be lowered by one level in comparison to the visual task area. For all values upwards of 750 lx, this means a standard value of 500 lx; for all values of 200 lx and below, the immediate surrounding area must be illuminated with the same illuminance as the visual task area itself.

Table 1.2: Connection between illuminance of the immediate surrounding area and visual task area illuminance as well as corresponding illuminance uniformity values according to EN 12464-1