LEDspan’s LEDs have a life expectancy of 70,000 hrs. If you use your lights for 10 hrs a day, 5 days a week, LEDspan’s lights will last over 26 yrs. The rated life of a light source is an estimate of average operational life. The measurement for “rated life” is (Bp) and is measured in hrs, where (p) is a %. A B10 rated life of 1,000 hrs means that 10% of the tested products failed and 90% lasted 1,000 hours. LED light sources have other important factors to consider. Lumen-maintenance life. “the elapsed operating time at which the specified % of lumen depreciation or lumen maintenance is reached, in hrs.” Rated lumen-maintenance life. “the elapsed operating time over which an LED light source will maintain the % (p) of its initial light output.” Rated lumen-maintenance life is measured in hrs with the % of light output denoted as (Lp). L70 of 50,000 hrs means the tested LEDs produce 70% of the initial light output at 50,000 hrs. The light output from all light sources decreases over time. LED modules slowly dim over time. Designers take this into account when designing a lighting layout. LEDspan Products = L70/B10.