According to DIN/EN 13032/2, the LOR (Light Output Ratio) describes the ratio of the luminous flux of the luminaire to the lumens of the lamps used. Luminaires with direct/indirect emission also specify the "DLOR" (Downward Light Output Ratio) and the "ULOR" (Upward Light Output Ratio) as separate components. These indicate the light intensity distribution of a luminaire in the lower and upper parts of the room.