What is the L70 rating for LED high-bay lights?

L70 refers to the number of hours it takes for an LED luminaire's luminous flux to depreciate to 70% of its initial value; it is an industry standard for measuring LED lifespan. For instance, an L70 rating of ≥50,000 hours means that after 50,000 hours of use, the luminaire retains at least 70% of its initial brightness. The L70 metric is particularly important for high-bay lights due to their long daily operating hours (often 12 to 24 hours). High-quality high-bay lights typically have an L70 rating of 50,000 to 100,000 hours.

Note: L70 is a statistically derived value; actual lifespan is influenced by environmental conditions.

You can require manufacturers to provide L70 reports based on LM-80 and TM-21 standards in procurement contracts. While other standards exist—such as L80 and L90 (which are stricter) and L50 (representing half the initial brightness)—L70 remains the most widely used metric.