Manufacturers set the record straight on the safety of LED street lamps.
By Jean Whatley
Shaun Fillion, LC Educator IALD, views exterior lighting from many perspectives—literally and professionally. He lives in Queens, New York, one of the five boroughs that make up New York City. Queens was the first of the five to switch to LED streetlights in the summer of 2016. Fillion isn’t entirely pleased.
“The street light across from my apartment throws a lot of light towards my building,” says Fillion. “It has a very high angle throw. I measured 1.5 footcandles outside my window. An ideally designed street-light optic should spread more of the light along the street while minimizing the light spill onto adjacent properties.”
Clearly Fillion isn’t your average consumer. He serves as RAB‘s Lighting Studio Manager and Program Director for the MPS-L Lighting Design program at the New York School of Interior Design. It doesn’t mean he can’t be slightly annoyed by the faulty design of the fixture on his street, which he’s quick to point out was not manufactured by RAB.
“As a resident, I don’t want that light spilling into my home from the unshielded street light. But as the guy out walking his dog on dark winter mornings, the streetlight brings light to the sidewalk and vertical illumination. I can see the other people jogging or walking their dogs or hanging out on the corner. The light helps me feel safe.”
The issue of safety – more specifically, the safety of LED street lamps – was the topic of controversial guidelines issued by the American Medical Association in June of 2016. Among the assertions by the AMA was that “high-intensity LED lighting designs emit a large amount of blue light that appears white to the naked eye and create worse nighttime glare than conventional lighting. Discomfort and disability from intense, blue-rich LED lighting can decrease visual acuity and safety, resulting in concerns and creating a road hazard.”
Dan Kennedy, Director of Corporate Marketing for Duraguard, might assert that misinformed physicians making sweeping recommendations about complex lighting engineering designs posed a hazard to the industry.
“When I’ve had to talk to people I need to convince, I put it this way: ‘Would you hire a doctor to pick your automobile? Would you hire a doctor to tell you how to fix your air conditioner? Or conversely, would you hire a lighting director to tell you if you need brain surgery or not?’,” says Kennedy. “It’s really simple. You should rely upon the expert in the field and the AMA chose not to rely on the IES as an expert resource, rather they just pulled a couple articles, grabbed a few snippets and created the report. It’s unfortunate.”
Some eighteen months after the AMA’s guidance was published however, the detrimental effects have been negligible, if not downright helpful.
While lighting industry experts such as the National Electrical Manufacturers Association (NEMA), the Illuminating Engineering Society (IES) the Lighting Research Center (LRC) and the Department of Energy (DOE) took on the AMA, manufacturers were adapting to ensure they could assuage concerns, salvage bids, and continue to meet customer needs. RAB launched a new product in 2017, the TRIBORO roadway lighting fixture that’s available at 2000K all the way up to 5000K.
“It was recognized in the 2017 IES Progress Report as a cutting edge fixture,” said Fillion. “I think part of the reason our product team introduced this 2000K was not so much to address the AMA, but was really about introducing a low color temperature LED to appeal to the risk averse or change averse municipalities.”
That was the first fall-out from the AMA guidelines – city councils or governmental entities delaying projects or modifying their specs. Kennedy said that Duraguard did see some projects where specifying buyers were requesting 2700K, after the AMA advised against using LEDs with correlated color temperature (CCT) exceeding 3000K.
“It was quite a flurry initially, lots of cities thinking about adopting ordinances, but it seems to have settled down some,” said Kennedy, who’s been active in the IES for decades. “I think it’s because all the electrical industry folks have come out now and said this is just not correct. You don’t need 3000K lighting to have safe lighting. You do need to design how the light is spread, where it’s used and how it is controlled, those are all good things, but the 2700K is not the single determinant that the light is good, bad or indifferent. I think people are starting to get that.”
From a geographic perspective, “the trend towards the warmer colors is working its way from West to East,” says Fillion. “Arizona, California, Nevada, those are the places we’re seeing the 3000K required by municipal ordinances or by Departments of Transportation. There’s some of that in Long Island and parts of the east coast as well.
“What’s interesting to me is, we see a definite difference between municipalities and DOTs; they are really neck-in-neck between 3000K and 4000K. So the cities have read and are responding to the AMA report. Some of them may have been reacting to the City of Phoenix or Las Vegas, with documentation of complaints that they received with the cooler color temperature.
“On the other hand, when you look at the trends we see in site lighting sales, most local properties are using 5000K or 4000K. Customers are choosing cool white light for their own properties, but when the public entities are looking to serve the public, I think they’re erring on the side of less change, less reason for complaints.”
Prudent manufacturers will make product lines available to accommodate every buyer on the risk versus benefit scale, but that doesn’t factor in one key driver for the swap to LED: government rebates.
“The other issue,” says Kennedy, “is the recent lumen-per-watt (LPW) requirement from the DesignLights Consortium (or “DLC”). Most companies don’t offer any fixtures at a 3000K or 2700K lumen-per-watt requirement because the lower the Kelvin temperature, the more phosphor is applied to the LED, and the lower the efficacy is. So for the same chip, same watts in, you get as much as ten to twelve percent less light from 4000K down to 3000K. That drops it below the threshold that they can get a utility rebate with a DLC label. For instance, we have a lot of fixtures that are DLC certified in 4000K and 5000K but none in 3000k because we can’t meet the efficacy requirements.”
Factoring all of these considerations into the mix, and being able to offer expert advice to public entities or commercial clients, should position the industry to retain its authority over its own products. Ironically, two recommendations in the AMA guidelines “encourages proper attention to optimal design and engineering features” and ” also recommends all LED lighting should be properly shielded to minimize glare and detrimental human health and environmental effects” are points which RAB’s Fillion couldn’t agree with more.
“I do think there is a responsibility that manufacturers have and that is to tailor and control glare from light fixtures. LED floodlights should all be developed with accessories like barn doors, hex-cell louvers, concentric rings, things that will help minimize light spill,” said Fillion.
Meantime, Fillion said he has a way to mitigate the annoying light trespass from the inferior fixture across the street from his apartment in Queens. It’s called a shade.
Tagged with research, street lighting
Discussion (2 comments)
If you think these lights are safe, let me install them by your families house first. I bet you said lead piping was safe for drinking water way back when too….
What the article does not say is that the efficiency difference between warmer white LEDs and 4000K is now down to a few percent. It also does not say that even though the efficiency is a tad less, you can still go down in wattage due to reduced glare. Hence, Los Angeles and Davis, CA both went down about 30% in energy use when they switched from 4000K to warm white LED street lights.