Cities try to adjust to new guidelines on LED lighting
Both the Department of Energy and a professional society of engineers have taken issue with some of the recommendations in last month’s AMA’s study, which calls on communities to minimize the output of glare-producing blue light from LEDs, properly shield the lights to reduce environmental impacts and use dimmers to better adjust lights to local conditions.
On Wednesday, the community of Lakewood Ranch, Florida, will open a round of bid proposals on the installation of LEDs along its major thoroughfares. Earlier this month, community officials called on bidders to retool their proposals based on the AMA recommendations, which encourage the use of lighting with a color temperature rated at 3,000 kelvins.
That type of lighting has a more orange-like glow, as opposed to lights rated at 4,000 K and up, which appear white but contain more bluish light. The blue light can be a road hazard, the AMA reported, because blue-rich light decreases visual acuity and produces nighttime glare. It also suppresses the hormone melatonin in humans, leading to disrupted sleep cycles, impaired daytime functioning and even obesity, the AMA argued.
Last week, the city council in Langley, Washington, decided to move forward on a project to replace all its 93 existing sodium-vapor streetlights by following the AMA’s guidance on LED lighting. The city opted for 3,000 K lights, which will save about $2,500 annually in energy costs, after several residents complained about the glare and other dangers they said were associated with more whitish lights.
Cities that have already installed LED lights that emit a color temperature of 4,000 K and up, however, face a more difficult decision. For example, Eugene, Oregon, in April completed a project involving the installation of thousands of LED fixtures in its neighborhoods, but the lights don’t conform to the AMA recommendations.
“We were in a natural holding pattern after installing nearly 5,000 LED fixtures,” Brian Richardson, public affairs manager for the Eugene Public Works Department, told AMI Newswire on Monday. “As with any new information, we will take time to thoroughly review the guidance statement from the AMA.”
The city has not yet opted to change out any of its newly installed lights, Richardson said, adding that city staff have received mixed reactions from citizens about the new lights.
“The city is committed to becoming more environmentally sustainable, with a focus on reducing our carbon footprint,” he said. “LED technology allowed us to use less energy, which in turn saved the city money.”
Indeed, LEDs, or light-emitting diodes, are much more energy-efficient than traditional incandescent lights, using only about 20 percent of the energy that’s needed for traditional lighting. They also radiate less heat and can last for decades.
LEDs are more expensive than other types of lighting, however, but over time cities save money because of their longevity and efficiency.
In Tulsa, Oklahoma, traffic operations manager Kurt Kraft told AMI Newswire that the city has installed LED lights emitting 4,000 to 5,000 kelvins in its central business district. "I'm not aware of any complaints against them."
Tulsa will take a wait-and-see approach to the AMA report, he said, noting that all kinds of lighting – fluorescent, computer screens, televisions, the sun – give off blue light, so it's hard to know if additional blue light from streetlights will create more problems. The more natural whitish lights may be superior in providing security, Kraft said.
The AMA guidelines have received some push-back from both government and industry. Jim Brodrick, solid-state lighting technology manager with the federal Department of Energy, posted a statement on the department’s website that indicated lights with lower correlated color temperatures may distort colors and result in reduced visibility.
Moreover, the implications of blue light emitted by LEDs are no different than exposure to blue light from any light source, Brodrick wrote.
Also reacting to the AMA guidelines, the National Electrical Manufacturers Association said some of the AMA recommendations raise serious concerns for industry. The association argued that no single solution – such as an emphasis on 3,000 K lighting – is appropriate in all situations.
“The AMA recommendation encouraging the use of 3,000 K correlated color temperature (CTT) or lower may compromise the ability of the lighting system to meet all critical design criteria for each unique application,” the association said in a prepared statement.
Brian Liebel, technical director of standards with the Illuminating Engineering Society, told AMI Newswire that the AMA released its findings without consulting the society. The engineering group is now conducting a review of the AMA study to see if it contains any significant new information to back up policy changes on outdoor LED uses.
“There is a level of concern,” Liebel said. “Engineers are getting feedback from cities.”
The AMA report said 10 percent of U.S. streetlights have been converted to LEDs. The AMA also acknowledged that the technology can help lower reliance on fossil fuels, but the study cautioned against poorly designed, high-intensity lighting.
“Despite the energy-efficiency benefits, some LED lights are harmful when used as street lighting,” Dr. Maya Babu, an AMA board member, said in a prepared statement.“The new AMA guidance encourages proper attention to optical design and engineering features when converting to LED lighting that minimizes detrimental health and environmental effects.”