L70 means that 70% of the output luminous flux after specified operating time

(usually 50,000 hours) are guaranteed. What is meant by this is that the LED is always

is still functional, but only provides a lower luminous flux. This leads

to a poorer lighting level.

B50 describes that after the specified operating time, only 50% of the LEDs have the

L-value. Accordingly, 50% of the LEDs provide more luminous flux than the L-value.


Reliable information on service life assumes reliable thermal management of the LED luminaire and normally refers to an ambient temperature (rated temperature) of 25° C.