Designing in lumen classes
Designing according to lumen classes is suitable for the approximate selection of luminaires. Independent of the efficiency increase with LEDs, the luminous flux specifies the utilisable illumination output. The more efficient the luminaire, the higher is the illuminance on the target plane. Efficiency decreases with excessive spill light. The required luminous flux can be determined via the illumination distance, the light distribution and the desired contrast ratio to the surroundings.