CALCULATING L70
Based on the in-situ temperature of the fixture, the TM-21 calculator using the LM-80
data of the LED chip manufacturer can be used to calculate the L70 of the fixture. For this
TKD, the in-situ temperature was found to be 42.2°C (lumen maintenance not shown in
Figure.2). Table 1 provides the L70, L80, L90, and L98 value using the TM-21 calculator.