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Troy, NY -  2/25/2005

Lighting Research Center industry group distributes guidelines for reporting LED life

The Alliance for Solid-State Illumination Systems and Technologies (ASSIST) has published recommendations defining and measuring LED life, as a first step toward establishing product standards.

The Alliance for Solid-State Illumination Systems and Technologies (ASSIST), an LED industry group organized by the Lighting Research Center (LRC) at Rensselaer Polytechnic Institute, has published its recommendations defining and measuring LED life for lighting.

“ASSIST recommends: LED Life for General Lighting” proposes a definition for the life of LED products for lighting, based on light output depreciation and appropriate light levels for different types of lighting applications. The group recommends 70 percent lumen maintenance (i.e., a 30 percent reduction in light output over time) as the useful life for general lighting applications; and 50 percent lumen maintenance for decorative lighting applications.

Because LEDs rarely fail catastrophically, “ASSIST recommends” uses the term “useful life” in its life definition. The end of useful life indicates when the light output from the LED product has decreased to a point where it becomes unacceptable for the lighting application.

“The purpose of ‘ASSIST recommends’ is to help manufacturers present information to end users in a consistent manner,” said N. Narendran, Ph.D., director of research and head of the solid-state lighting program at the LRC. The information and recommendations presented in “ASSIST recommends” are based upon LED life tests conducted at the LRC and information found in literature regarding noticeable light level changes. In addition, the LRC gathered input from leading LED manufacturers and the traditional lighting community while preparing these recommendations.

The publication also provides methods for measuring and extrapolating data to estimate the life, in hours, of an LED component and an LED-based system, as well as sample data sheets for how companies should record and present life information for their products. Because LED fixture life can vary depending on its packaging, the “ASSIST recommends” publication calls on both LED component manufacturers and fixture/system manufacturers to test and provide life information for their LED products.

“The LED and lighting industries have not set a standard for LED life at this point,” said Dr. Narendran. “We hope ASSIST’s recommendations will further the current dialogue on this issue and offer a starting point for standards-setting bodies.”

A free download of “ASSIST recommends: LED Life for General Lighting” is available on the LRC Web site at


The Alliance for Solid-State Illumination Systems and Technologies (ASSIST) is a program developed by the Lighting Research Center to advance the effective use of energy-efficient solid-state lighting technologies. ASSIST is a collaboration between researchers, manufacturers, utilities, and government organizations. Its goal is to identify and reduce major technical hurdles and help LED technology gain widespread use in lighting applications that can significantly benefit from this rapidly advancing light source technology. On behalf of ASSIST, the LRC conducts research, demonstration and evaluation, and educational activities. Beyond technical research, ASSIST has been active in fostering discussions between traditional luminaire manufacturers and LED manufacturers.

ASSIST sponsors include Boeing, GELcore, New York State Energy Research and Development Authority, Nichia America Corporation, OSRAM SYLVANIA/OSRAM Opto Semiconductors, Philips Lighting, and the U.S. Environmental Protection Agency.

The LRC's Solid-State Lighting Program conducts research and educational programs to enhance this technology and help it gain acceptance for general illumination purposes. The LRC's multidisciplinary team researches how lighting systems interact; how people perceive and react to lighting conditions; and how to use LEDs to replace less efficient lighting.

About the Lighting Research Center
The Lighting Research Center (LRC) at Rensselaer Polytechnic Institute is the world's leading center for lighting research and education. Established in 1988 by the New York State Energy Research and Development Authority (NYSERDA), the LRC conducts research in light and human health, transportation lighting and safety, solid-state lighting, energy efficiency, and plant health. LRC lighting scientists with multidisciplinary expertise in research, technology, design, and human factors, collaborate with a global network of leading manufacturers and government agencies, developing innovative lighting solutions for projects that range from the Boeing 787 Dreamliner to U.S. Navy submarines to hospital neonatal intensive-care units. In 1990, the LRC became the first university research center to offer graduate degrees in lighting and today, offers a M.S. in lighting and a Ph.D. to educate future leaders in lighting. Learn more at

About Rensselaer Polytechnic Institute
Founded in 1824, Rensselaer Polytechnic Institute is America's first technological research university. Rensselaer encompasses five schools, 32 research centers, more than 145 academic programs, and a dynamic community made up of more than 7,900 students and more than 100,000 living alumni. Rensselaer faculty and alumni include more than 145 National Academy members, six members of the National Inventors Hall of Fame, six National Medal of Technology winners, five National Medal of Science winners, and a Nobel Prize winner in Physics. With nearly 200 years of experience advancing scientific and technological knowledge, Rensselaer remains focused on addressing global challenges with a spirit of ingenuity and collaboration.