How is LED life expectancy measured?

The lifespan of traditional incandescent bulbs is calculated quite simply. It’s referred to as Average Rated Life (ARL), which is the length of time it would take for 50% of the sampled bulbs to fail completely (an average of 1,000 hours for traditional bulbs).

The lifespan of the modern LED, on the other hand, is measured differently.

That’s because LED lights rarely fail completely as traditional bulbs do. Generally spe

So LED lifespan needs to be calculated in a less binary way, leading manufacturers to define it as the point at which luminosity has reached 70% of initial output. This measurement is usually expressed as B50-L70, which is shorthand for the time that 50% of LED bulbs in ideal conditions will have 70% of their rated output.

However, unlike traditional bulbs that end up at a single maximum figure of 1000 hours, the B50-L70 of LEDs ends up as anywhere between 10,000-50,000 hours.

Every LED will have an L70 rating, which is usually calculated in hours. For example, an LED bollard with L70 of 50,000 will - in 50% of all cases - have a rated lifespan of 50,000 hours, at which point they will emit 70% of their original output. If an LED has L50 of 50,000 hours, its output decays faster than one with L70 of 50,000 hours, and so on.