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What is LM79, LM80 and LM70 testing on lights.


LM79, LM70, LM80 are test procedure developed and approved by illumnating Society of North America (IESNA) on LED lights.

LM80

This test LM80 gives the age or lifetime of LED modules used inside LEd bulb and Luminaries. LM80=60,000 means after 60,000 hours of operation of LED module, LED module lumnious flux ( or simple light from LED module) will only left 80 percent of the intitial light output or luminous flux.

LED lights does not fail at once ..their lighting output fall over time ..as they are composed of many LED modules and LEDs in LED modules will slowly slowly give less output ..this test tell you that ..

Generally LED manufactures gives LM80 value at 25 degree ambient temperature ..

The test is developed and approved by Illumanating Engineering Society of North America (IESNA).

As the test is developed and approved by IESNA so this test is conducted using IESNA approved test procedure and test equipment.

One more thing, you have seen LM values LM80= 50,000 hours or 60,000 hours.

So the question is …does the lab test a light for 50,000 hours or 60,000 hours ??

The answer is a big No ??

Test is conducted for 10,000 test hours and fall in lumnious flux of module is noted after each 1000 hours ..and a graph is drawn betwen Light output and test hours..

And for 6 times the test hours (60,000 hours), fall in lumnious flux is find out by extending this graphical realation.

So how this extending of graphical realation is done ..it is done by a standard TM-21, developed by IESNA.

Kindly note that this test is on LED module , not LED light (luminaries and bulb) so it is conducted by original LED manufactures , not light manufacturers ..

LM70

LM 70 is similar to LM80 ..both give life time of LED light ..

LM70=50,000 hours.. means after 50,000 hours , light output of LED module will only be 70 percent of initial Light output.

It is also given generally at ambient temperature of 25 degree.

Kindly note that this test is on LED module , not LED light (luminaries and bulb) so it is conducted by original LED manufactures , not light manufacturers ..

LM79(Lumen Maintenance)

LM79 is a test that is conducted on soild state lighting (LED lamps and luminaries) to find out electrical and photometric properties of LED lights ..

This test LM-79-08 is approved by Illumanating Engineering Society of North America (IESNA) and most of the world and LED manufactures has adopted this standard.

Electrical and photometric properties include the following :

  • Total light output (luminous flux)
  • Efficacy (lm/w)
  • Colour properties like CRI, CCT
  • Luminous intensity distribution
  • Electrical parameters like Power, current , power factor

As the test is developed and approved by IESNA so this test is conducted using IESNA approved test procedure and test equipment.

Kindly read below article to know other terms and definitions related to lighting like CRI, CCT etc.


One Comment

  1. Sonu

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