Maintenance of light flow

The maintenance of light flow, also known as a decline in lumen or lumen expectation, describes the decrease in the luminous flux of a light source over its lifespan. Over time, every light source loses brightness, be it due to the aging of the lamps, pollution of the cover or material fatigue. The maintenance of light flow is given in the percentage of the original luminous flux, for example L70, which means that the light source reaches 70 % of its original luminous flux.

This process is particularly important for LEDs, since its long lifespan often includes a slow, continuous decrease in brightness instead of a sudden failure as with incandescent lamps. A high level of light flow maintenance is a quality feature of modern light sources and is taken into account in the lighting planning to ensure that rooms remain sufficiently illuminated even after prolonged use. Regular cleaning and maintenance can also help maximize the maintenance of light flow.