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utilance, <of an installation>
quotient of the luminous flux received by a reference surface and the sum of the individual output fluxes of the luminaires of the installation
Note 1 to entry: The utilance has unit one.
Note 2 to entry: This entry was numbered 845-09-53 in IEC 60050-845:1987.
Note 3 to entry: This entry was numbered 17-1382 in CIE S 017:2011.