Lumen Maintenance
For LED light sources, LM-80 defines lumen - maintenance life as “the elapsed operating time at which the specified percentage of the lumen depreciation or lumen maintenance is reached, expressed in hours.” Rated Lumen Maintenance Life: Rated lumen-maintenance life is measured in hours with associated percentage of light output, noted as L p . In other words, L 70 of 30,000 hours means that the tested LEDs produce 70% of the initial light output at 30,000 hours. If an LED has L 50 of 30,000 hours, its lumen output decays faster than one with L 70 of 30,000 hours. LM80: LM-80 is a testing procedure on the lifespan of LED light source. It’s an IESNA document that the manufacturers must follow to test the lifespan of their LEDs. Basically it tells you how the LEDs must be tested and what information must be included in the LED lifespan report.