A new report was published by US Department of Energy that examines lifetime and reliability of SSL products and they makes it clear that current standards could not provide an accepted way of defining system life.
The solid-state lighting (SSL) industry has come a long way in establishing standards for testing and rating both LED components and LED-based systems, although as the US Department of Energy (DOE) points out, there is still no definitive way to rate system life expectations. There are improved ways to test for project lumen maintenance, but other failure mechanisms including driver life and system-level color maintenance remain hard to quantify.
The IES LM-80 standard provides definitive test methodology for white LED components. Most people discuss LM-80 relative to lumen depreciation and specification of time to L70 or 70% of initial flux output measured in thousands of hours. But LM-80 also defines component color maintenance and color shift. The IES TM-21 standard adds a way to project life beyond the 6000 hours of testing required by LM-80.
The IES LM-84 standard will define methods for measuring both lumens and color maintenance at the LED Light covering Commercial LED Downlight, LED Light Panel and Linear Tube.
Moreover the TM-28 will prescribe methods to project lamp life based on LM-84 data. Later the IES may add projection methods for luminaires to TM-28.
The DOE also mentioned the possibility that the industry may be better off with products rated for shorter lifetime such as 10–15 years rather than say 30 years, because lighting is often remodeled on a shorter cycle. We covered similar ground in a recent editorial. The DOE did add that shorter life impacts sustainability because more waste material is generated.
One thing that the fact sheet does not address is how lifetime and reliability are impacted in products that use a mix of colored LEDs, or a technology such as remote phosphor that relies on royal blue LEDs, often referred to as blue pumps. The existing standards such as LM-80 only define test methods for phosphor-converted white LEDs. But other system architectures are becoming very popular in some applications
OKT Lighting is the Commercial LED Lighting Manufacturer which focuses on the American Market. ALL Commercial LED Lighting including LED Downlight, LED Panel Light and LED Tube are passed LM79 while the chips are LM80 Qualified, which can meet the the lifetime and reliability of LED lighting from DOE.