The Department of Energy, working with a group called the Next Generation Lighting Industry Alliance, has completed a study on the failures of LED lighting. Among its findings it reports that the lifetime of an LED bulb should “have at least 50% confidence level. This recommendation has not been widely observed but should be.”
The study also concluded that LED failure does not necessarily mean the bulb fails to work. Instead, there can be three potential failures, including catastrophic failure, unacceptable lumen depreciation or unacceptable color shift.
The DoE also thanked members of the alliance, which includes members from lighting manufacturers Phillips, GE, Sylvania, Lunera Lighting, Finelite, Lumentek, and Cree.
The summary to the report says, “The emergence of solid state lighting (SSL) with its high efficiencies and long lifetimes has led to the potential for significant energy and cost savings to our nation once wide-scale adoption occurs. Light emitting diodes (LEDs) are the heart of SSL lighting products and can provide long lifetimes that last well beyond 50,000 hours of operation, much longer than most conventional light sources. The end of life for all lighting technologies is signaled by the loss of light, but this may be less evident for LED luminaires, where the light output may continuously fade or the color may slowly shift to the point where low light output or an unacceptably large color change constitutes practical failure.”
It continues, “after further research, it is understood that electronics failures in the driver or degradation of optical components can often occur long before LED lumen depreciation causes failures. Lifetime claims should take into account the whole luminaire system, not just the LEDs. A system reliability model that integrates the failure mechanisms in the various luminaire subsystems would create a much more accurate lifetime claim from LED luminaire manufacturers.”
Recommendations for manufacturers from a 2014 study include, “providing clear warranties, report compliance with industry standard measurements, and commitment to best practices for designing and developing long-life, reliable products.”
The group’s recommendations for buyers includes, “Focus on qualifying suppliers. Understand what methods the vendor is using to support reliability or lifetime claims, and require data.” The report also recommends to buyers: “Understand the warranty. What is covered and what is not?”
You can read the entire April 2017 study here.
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