1. Designing with led

2. Maintenance factors
Maintenance factors are important for ensuring the future compliance of our designs. In essence, a maintenance factor is employed to make sure we are designing for worst case scenarios.
The formula we use under AS/NZS1680 is LLMF x LSF x LMF x RSMF where:
LLMF= Lamp Lumen Maintenance.
LSF = Lamp Survival Factor.
LMF = Luminaire Maintenance Factor.
RSMF = Room Surface Maintenance Factor.
LMF and RSMF are clearly defined under AS/NZS1680 but what about LLMF and LSF when it comes to LED luminaires?

3. How do we predict an led’s lumen-maintenance life?

4. ? LED Light Source LED Luminaire LM-80 standard LM-79 standard
LED lumen maintenance data for the duration of test
Covers total flux, electrical power, and chromaticity
TM-21 standard
Does not cover luminaire lumen maintenance
Projected long-term lumen maintenance ?

5. lumen-maintenance for led light sources

6. LM-80
Approved method for measuring lumen depreciation of solid- state (LED) light sources, arrays and modules.
LM-80 requires testing of LED’s for hours, and recommends testing for hours.
It calls for testing at three surface temperatures (55° C, 85° C, and a third temperature to be determined by the manufacturer) so that users can see the effects of temperature.
LM-80 provides no determination or estimation of expected life or lumen output beyond test data.

7. TM-21
TM-21 defines the method for taking LM-80 data and making useful LED lifetime projections.
Among other things, TM-21 will consider:
If total LM-80 data period is between 6,000 and 10,000 hours, we consider the last 5,000 hours.
Projections are limited to 6 times the available LM-80 data period so projected and reported lifetime may or not be the same.

8. Example of TM-21 prediction
1000 – 6000 hr: L70(6k) = hr
5000 – hr: L70(10k) > hr limited by 6X test period

9. Example of TM-21 prediction
1000 – 6000 hr: L70(6k) = * hr
5000 – hr: L70(10k) = hr
*L70(6k) = hr
limited by 6x test period.

10. Presenting LED lumen-maintenance life
Given as Rated Lumen Maintenance Life, (Lp). The elapsed operating time over which the LED light source will maintain the percentage, p, of its initial light output, for example:
Time to 70% lumen maintenance = L70
Time to 90% lumen maintenance = L90
This is different from LED rated life which is the life value assigned to a particular LED. This is commonly a statistically determined estimate of median operational life. That is, when a determined population of the LED’s fail. Usually given as B10 or B50, ie. when 10% or 50% have failed.

11. What happens when LEDs are in a luminaire?
Currently many LED luminaire manufacturers use test results typically provided by the manufacture of the LED board. However, there is a disconnection between the LM-80 test results and the results within a LED luminaire.
There is no validated way to translate the lumen maintenance curve of an individual LED into a curve for the LED luminaire, primarily due to the luminaire’s thermal performance.

12. How do we predict life for an LED luminaire?
LM-80 and LM- 21 data alone is not satisfactory.
There is no current standard for predicting an LED luminaires lumen maintenance life.
There is, however, a standard for testing an LED luminaires thermal performance!

13. Thermal testing for AS/NZS 60598.1:2003

17. How do we apply these results?
Extrapolating from LM-80 data we apply the luminaire data we obtain from AS/NZS :2003.
For example:
Eagle Lighting Vertex luminaire has a temperature rating of 41°
Using the LM-80 and our AS/NZS :2003 data, we are able to determine an appropriate TM-21 prediction of L90/30,000hrs, approximately 10 years of useful life
Therefore we can apply a LLMF of 0.9 in our designs, based on a useful life of the LED board of 30,000 hours

18. How do we apply these results?

19. Why is an accurate l90 figure so important?

20. LED lumen maintenance effects the design maintenance factor
Designing with L90 figure
Formula for LED luminaire:
LLMF x LSF x LMF x RSMF = MF
0.9 x x 0.91 x 0.98 = 0.80mf
Designing with L70 figure
Formula for LED luminaire:
LLMF x LSF x LMF x RSMF = MF
0.7 x x 0.91 x 0.98 = 0.60mf VS

21. 0.8MF vs 0.6 MF
No maintenance factor
24 luminaires required

22. 0.8MF vs 0.6 MF
0.8 maintenance factor
30 luminaires required

23. 0.8MF vs 0.6 MF 0.6 maintenance factor 40 luminaires required
If you are designing with L70 figures and a 0.6MF, the difference is 30% more fittings! 30% more energy, 30% more cost, 30% more maintenance…
This is simply not practical
0.6 maintenance factor
40 luminaires required

24. What if we get our lumen maintenance life from the LED board?
A typical L90 life expectation for an LED board.
L90 - 9,000 hours.
A typical L70 life expectation for an LED board.
L ,000 hours

25. This means the design could be non-compliant in a typical office after less than 3 years of operation!

26. What if we get our lumen maintenance life from the LED board?
ELA Vertex with a Tc point of 41° as per AS60598 test results

27. What life are you quoting your client?

28. Questions?