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In certifying Luminaires with an LED Light Engine (LLE) from the Certified Subcomponent Database (CSD), is it necessary to take the in-situ temperature of both the LLE's case temp point (Tb) and the LED TMP used in the LLE for lifetime calculation? Follow

An in-situ temperature measurement of the LED Light Engine’s case temperature measurement point (Tb) is all that is needed when certifying Luminaires if all of the following conditions are met: a) the light engine is listed on the certified lighting subcomponent database (CSD); b) the light engine has an LM-82 temperature test report from an EPA-recognized laboratory that includes performance data at three different case temperatures measured at both the light engine manufacturer’s designated point (Tb) and the corresponding LED case temperature (TMP); and c) luminaire manufacturer claims a lifetime based on the lumen maintenance of the light engine at a temperature point that is higher than what was measured at the Tb point with the light engine installed in a luminaire.  The luminaire manufacturer may also choose to measure the hottest LED’s TMP with the light engine in the luminaire to potentially allow a higher lifetime claim.

Example: An LED Light Engine is listed on the CSD with performance data at Tb of 35°C, 50°C, and 70°C.  A manufacturer designs a non-directional luminaire to utilize the light engine, and when installed in the luminaire, the light engine case temperature is 63°C.  The luminaire manufacturer can utilize the light engine’s lifetime data at 70°C.  If the manufacturer wants to claim a higher lifetime, they could choose to measure the TMP of the LEDs in the light engine, while installed in the luminaire, and use this data in the TM-21 calculator.


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