LEDs typically exhibit very long operational life characteristics and, depending on drive current and use conditions, can be in use for 50000 hours or longer. The light output from LEDs slowly decreases over time. This characteristic of declining output without catastrophic failure creates a risk that an LED-based lighting product near end-of-life may be operating, but performing outside the product’s specification, or outside required codes, standard practices or regulations. LEDs may also undergo gradual shifts in the emitted spectra over time that may result in unacceptable appearance, color rendering or degraded efficacy.
This document describes the procedures by which LEDs are tested for the luminous (or radiant, or photon) flux maintenance and chromaticity maintenance or wavelength changes over time when operated under controlled environmental and operational conditions. The resulting measurements may be used for comparison of LEDs, and they may be utilized in models that project long-term changes in light output during the life of the LEDs.
ANSI/IES LM-80-15 does not provide guidance or make any recommendation regarding predictive estimations or extrapolation for the maintenance characteristics beyond the time duration of the actual measurements.
