Good LEDs in poorly engineered products live fast and die young. Early entrants advertising 100,000 hrs of product lifetime failed to live up to the hype, and have given the industry a bit of a black eye. Even now, several years into the game, the industry lacks sufficient standards to test for LED/SSL system reliability over life.
However, government agencies and numerous utility incentive programs are improving the reliability of product information. Together with specifiers, LED lighting manufacturers, and standards-setting bodies, they work toward a common goal: rapid deployment of this new, energy-saving technology.
Beyond chromaticity (discussed in a previous article), there are widely accepted consensus-based performance testing standards, issued by the Illuminating Engineering Society of North America:
- LM-79, for luminaire systems, including drivers.
- LM-80, which addresses LED packages, arrays, and modules only.
- The TM-21 formula to extrapolate long-term lumen maintenance.
- LM-82 for luminaires using LED light engines and integrated “replacement” lamps (a coming standard that will test under different temperatures).
“For a while there were no products coming in, and finally it took hold. Now testing to LM-79 is expected, and we have 3219 products in our database today,” according to Program Manager Marci Sanders. “The specifiers pressured manufacturers and pushed for the label.” As a next step, Lighting Facts is beginning to spot-check listed products; testing off-the-shelf products for consistency with listed data.
Major changes are underway in the Environmental Protection Agency’s Energy Star program, as LED certification is being rolled into the new Luminaires Version 1.0 specification. Because of new performance specifications and the new requirement for third-party certification of lab results, implementation of the new specification has been delayed until 2012.
The delay exemplifies the difficulties of transitioning from a separate standard for LEDs to one standard for all luminaires regardless of source. “There’s some lack of clarity in my opinion,” said Kevin Fagan, VP of engineering for Juno Lighting Group by Schneider Electric. “We certainly don’t want the new standard to be a barrier for innovation, so we’re working with EPA to understand some of the costs associated with the new program and make sure we’ve created a balance between protecting the consumer and not driving up the cost of the product.” EPA also plans to conduct verification testing of off-the-shelf products labeled with the Energy Star.
LM-79 and LM-80 test for lumen maintenance, but that is only one attribute of LED performance, and the LEDs are only one component of the system – and often not the cause of failure to perform. Nevertheless, lumen maintenance values are widely used to determine the life rating of LED systems.
In response, Wilger Testing Co. has developed a fault-tree analysis program that gives failure risk data and expected life for the complete electrical and mechanical luminaire system.
“Specifiers should look for LM-79 and LM-80 tables. They should look for Energy Star compliance. These will give an indication that the product is of quality,” Jerry Plank, Wilger’s CEO and founder recommended. “However, these standards look at predictability of LED performance in life, not specifically for the system performance…. The manufacturer should provide third-party test data, from an accredited lab, stating that they’ve looked at that aspect of system life.”
As they look to the future, all the stakeholders are working toward new testing metrics and performance requirements. By separating the pretenders from the performers, they create confidence in the marketplace.