A selection of 31 of those lamps passed the 40,000-hour point of continuous operation in July 2015. The average lumen maintenance for the 31 lamps after 40,890 hours was 95.6%, with no failures. At that rate it would take an average of 194,765 hours of operation for the lamps to reach 70% lumen maintenance (L70), if no other failure modes came into play before then. The average chromaticity change (?Δu’v’) of the 31 lamps after 40,890 hours of operation was 0.00093 – a minuscule difference indicating that there was no detectable color shift, and that the light emitted today is indistinguishable from the light emitted four years ago.
194,765 hours to L70 (70% lumen maintenance)!!!! To help you with the math, that’s 22.2 freakin’ years of nonstop, 24/7 operation!
Burn, baby, burn! I hope the DOE keeps this test running for a few more decades!!!! Let’s see how long it takes to L50! MTBF, anyone?