11.3. Time of Maintenance

Maintenance work at a lighting installation must be done at the latest if and when the maintenance illumination has reached the minimum admissible value. Here the following values apply:

Indoor, sports fields and outdoor lighting

E ‘ ‘ m = 0.8 En
E ‘ ‘ a = 0.8 En

Street lighting

E ‘ ‘ m = 0.7 En
L ‘ ‘ m = 0.7 Ln.

From this follows, that the maintenance of indoor lighting installations has to be done at the latest, if and when the nominal illumination on the illuminated surface has lowered to the value of 0.8 En, with street lighting installations to the value of 0.7 En. The right time for maintenance is found out by regular measurings of the illumination at fixed control measuring points, at least every half year.