LED Lighting Technology

- Jul 16, 2019-

Traditional lighting sources experience obvious failures after roughly 10,000 hours of operations. As they near their endpoints, those sources have reduced lumen values and become noticeably less bright. They finally stop generating light altogether as filaments and other sources of light generation break or become inoperable.

LED lamps typically experience different termination patterns. The solid state diodes that generate an LED’s illumination will not degrade, but the drivers that control them will falter and the bulbs will slowly generate lower lumen levels. This lumen reduction may not be apparent because it happens slowly over longer periods of time. Recognizing this, LED manufacturers will refer to LED lifespans in terms of lumen levels that track the percentage of full illumination generated by an LED when it is first put into operation. Thus, after 50,000 hours of operation, and LED lamp might still be generating light at 80% of its original light output (which is marked as “L80”). That 80% may or may not be adequate for a specific lighting application, but the manufacturer will use it as a measure of when the LED bulb should be replaced. (Currently, most manufacturers have adopted an L70 rating for recommended replacements.) For some applications, LED bulbs can continue to be used down to an L50 rating, well beyond a manufacturer’s recommended replacement level. LED lifespans are therefore specific to the uses and facilities in which they are installed.

The good news is that regardless of specific installations, over the past several years LED manufacturers have steadily increased the lifespan of LED lamps such that they maintain higher lumen levels for longer periods of time. These increases have been driven in large part by better thermal control of the LED bulbs and drivers. Heat is a primary cause of LED degradation. LED lamps remain cool to the touch, but excess heat can build up in the drivers that power those lamps. Innovative manufacturers, including Cary, have developed heat sink technology that effectively reduces thermal degradation of LED lamps to extend their lifespan with higher lumen levels. Combining advanced thermal controls in the lamps themselves with lighting system controls than reduce usage and electrical power consumption by the lamps in some cases has doubled LED lifespans to 100,000 hours.

Regardless of how an LED lifespan is determined and of how long an LED lamp remains in operation at any facility, an organization that transitions to LED technology will see substantial savings from lower electrical power consumption and reduced maintenance costs.