service illuminance, <of an area>
average illuminance during one maintenance cycle of an installation averaged over the relevant area
Note 1 to entry: The area can be either the whole area of the working plane in an interior or the working areas.
Note 2 to entry: This entry was numbered 845-09-60 in IEC 60050-845:1987.
Note 3 to entry: This entry was numbered 17-1166 in CIE S 017:2011.