lamp luminous flux maintenance factor
lamp lumen maintenance factor
quotient of the luminous flux of a lamp at a given time in its operational life and the initial luminous flux
Note 1 to entry: The lamp luminous flux maintenance factor has unit one.
Note 2 to entry: This entry was numbered 845-07-65 in IEC 60050-845:1987.
Note 3 to entry: This entry was numbered 17-636, 17-635, and 17-686 in CIE S 017:2011.