The visual task areas and the surrounding area must be provided with a sufficient illuminance Eh. The "screen work" visual task area must be illuminated at 500 lx. This also applies to individual VDU workstations, e.g. in a storage facility or a banking or exhibition hall where the illuminance value can be lower according to EN 12464-1, e.g. 200 lx for general storage work.

Good visual communication with the work room and the persons present requires good spatial recognisability, particularly of facial features (see chapter 1.2.9 "Spatial lighting, direction of light, modelling"). The photometric measurement for describing this lighting quality criterion is cylindrical illuminance Ez or semi-cylindrical illuminance Esz (see figure 1.94). On cabinet and shelf unit areas, sufficient vertical illuminance Ev must be provided for reading capability, e.g. 175 lx (see figure 1.95).

The wall surfaces (primary surfaces) must be illuminated with at least 75 lx maintained illuminance and the ceiling must feature a maintained value of at least 50 lx, both areas at a uniformity of at least 0,10.

Figure 1.94: Explanation of the horizontal illuminance Eh, the vertical illuminance Ev, the cylindrical illuminance Ez and the semi-cylindrical illuminance Esz

Figure 1.95: Example for office lighting with Ev ≥ 175 lx on cabinet and shelf unit areas