A National Lighting Bureau (NLB) panel suggests if energy efficiency is the main focus for future outdoor lighting, the actual quality will be inferior to what it is today.
The U.S. Department of Energy (DOE) has predicted by 2020, 75 percent of outdoor lighting will use light-emitting diode (LED) technology. During its annual lighting forum, the NLB panel discussed the forecast and offered its own hypotheses.
Bob Parks, executive director of the Smart Outdoor Lighting Alliance (SOLA) said new research demonstrates some outdoor lighting provides better nighttime visibility when not uniform because contrast is improved. The same research also showed illumination levels could be reduced by up to half the contemporary recommendations with no change to visibility when illumination is provided by broad-spectrum white-light sources, like some LEDs.
Currently, outdoor lighting standards are outdated because they specify illumination levels much brighter than broad-spectrum white light. Most outdoor lighting owners continue to follow current standards to avoid legal action against visibility in accidents. For example, the New York City Department of Transportation (DOT) is changing 250,000 street and highway lighting units to LED units over the next two years, but still conforming to today’s standards. Parks said this might decrease visibility, save less energy, and produce more glare because today’s standards do not adhere to newer technology.
Panel member Mark Lien, director of government and industry relations for an LED manufacturer said the reason standards are behind is due to the industry’s accelerated technology advances. Change occurs before new standards can be implemented causing a delay in the application of new technologies. One of these new technologies not being utilized is dynamic spectral tuning, which changes color temperatures so bright white-light would be emitted during rush hour for effective visibility and warmer light would be emitted later at night for visual comfort.
A third panel member, Janet Lennox Moyer, founder of the International Landscape Lighting Institute added when color temperatures of LEDs are the same as traditional legacy lamps, their light appears less warm. She said dynamic spectral tuning can reduce the disparity in the appearance, but widespread application of this particular technology can only occur when standards exist.
To view the entire panel discussion, visit www.nlb.org.
For more on LEDs, see these articles in The Construction Specifier:
- “Car Dealerships and LEDs: Implement Sustainability and Reduce Costs,” by Jeff Gatzow;
- “LED Luminaires for Parking Lots,” by Kevin Orth;
- “The Center of Attention Custom Commercial Chandeliers,” by Robert Cohen; and
- “LED Luminaires Provide Lesson in Energy Savings,” by Mark Bolten.
