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Troy, N.Y. -  6/3/2013

User-based Definition for Lamp Dimming Proposed in LRC's ASSIST recommends Publication

LRC laboratory dining room for dimming experiments. Click for larger image.The Alliance for Solid-State Illumination Systems and Technologies (ASSIST), a program of the Lighting Research Center (LRC) at Rensselaer Polytechnic Institute, recently released a new publication that addresses the issue of how lamps should dim in terms of their “look and feel” during the dimming process. The publication, ASSIST recommends… Dimming: A Technology-neutral Definition, provides a recommended definition for lamp dimming in residential and hospitality applications, based on research of existing industry standards, laboratory evaluations of lamp and dimming control performance, and psychophysical experiments conducted to determine common user expectations and preferences.

As new replacement lamp technologies become viable for many applications, manufacturers must design for the many facets of general illumination that the consumer expects, like dimming with standard wall dimmers. LEDs are intrinsically dimmable light sources and are commonly marketed as such; however, that does not mean that all integrated LED lighting products, particularly replacement lamps for incandescent lighting, are dimmable, or that residential dimmable LED products provide the same end-user experience when coupled with the existing installed base of dimmers. Compact fluorescent lamps have similar issues as well. Thus, dimming has been often discussed as one feature that needs to work well for energy-efficient lighting to achieve widespread adoption in general lighting applications.
Even though dimming is a feature commonly expected in many lighting applications, there is no standard definition for dimming in the industry.  Over a two-year period, researchers from the Lighting Research Center at Rensselaer Polytechnic Institute, on behalf of ASSIST, conducted technology performance and compatibility evaluations, human factors experiments, and reviews of existing industry standards to better understand the different aspects of lamp dimming. The results of this research led to the published ASSIST recommends, which outlines recommended minimum and maximum light levels, thresholds for dead travel, flicker, and audible noise, and definitions for dimming profile and system efficacy measurement.
Nadarajah Narendran, Ph.D., LRC director of research and organizer of the ASSIST program, notes that the goal of ASSIST’s dimming recommendation is to have manufacturers understand and meet users’ expectations for dimmed lighting, helping LED technology to gain widespread use in lighting applications. “The LRC and ASSIST’s industry members are interested in understanding the technical problems impeding market acceptance of LED lighting, and dimming is one focus area. By understanding the compatibility issues and what users want when they dim their lights, we can improve not only the dimming experience but also the likelihood that homeowners will permanently switch to energy-efficient LED lighting,” said Dr. Narendran.
The ASSIST recommends publication is available on the ASSIST website at
An overview of the dimming research conducted by the Lighting Research Center is available at
The Alliance for Solid-State Illumination Systems and Technologies (ASSIST) was established in 2002 by the Lighting Research Center as a collaboration between researchers, manufacturers, and government organizations. ASSIST’s mission is to enable the broad adoption of solid-state lighting by providing factual information based on applied research and by visualizing future applications. The Lighting Research Center conducts research, demonstration, and educational activities on behalf of ASSIST. ASSIST is sponsored by 3M; Acuity Brands Lighting; Amerlux; Bridgelux; Cirrus Logic; Cooper Industries; Cree; Dow Corning; Federal Aviation Administration; GE Lighting Solutions; ITRI, Industrial Technology Research Institute; Intematix Corp.; LG Electronics; LG Innotek; Lite-On; New York State Energy Research and Development Authority (NYSERDA); OSRAM SYLVANIA/OSRAM Opto Semiconductors; Philips Lighting; POSCO LED; Samsung; Seoul Semiconductor; Soraa; Toshiba; United States Environmental Protection; WattStopper.

About ASSIST recommends
ASSIST recommends is a publication program of the Alliance for Solid-State Illumination Systems and Technologies (ASSIST) that offers formal recommendations to the LED and lighting communities about issues important for the reliable performance of LED lighting and its comparison to other light source technologies. The first ASSIST recommends publication in 2005 provided a definition and method for estimating the useful life of LED lighting, which later became the basis for the Illuminating Engineering Society’s LED lumen maintenance standard, known as LM-80. The publications available include recommended definitions, testing and measurement methods, calculation methods, and best practices. All ASSIST recommends publications can be downloaded for free at

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.