MarQuee LED L70

What does L70 refer to in the following sentence (MarQuee LED L70 of 239,000 hrs. at 85°C for outstanding module life)?

This highlights just how energy-efficient LEDs are, and you should compare L70 ratings to maximise your energy savings. MarQuee LED has the longest lasting LED on the market as L70 of 239,000 means a life of approximately 40 years if running at 12 hours a day! Remember, the better the L70 rating, the longer your LEDs will last.

Lumen maintenance measures the light produced by a light source when it’s brand new. It compares it with its light output at a specific time in the future. So a light source which emits 1,000 lumens when new and 700 lumens after 50,000 hours of use has a lumen maintenance of 70% at 50,000 hours. In other words, it has an L70 of 50,000 hours. While lumen maintenance ratings of L50, L80 and L90 exist, L70 is most commonly used. Why? Because the human eye cannot detect the difference in a light’s output until it has reduced by 30%.