Dr. Bob Adams, with C&W Energy Solutions, has been advising us on outdoor lighting issues. He will be in Ivins next week to meet with us, Mayor Hart, and City staff to discuss issues we should consider as we work on revisions to the City’s existing Outdoor Lighting Ordinance.
Blue Light Impairs Vision & Safety
Here is a 37 minute video of a presentation Dr. Adams gave a couple of years ago. If you don’t have time to watch it all, fast forward to the 14:00 minute mark and watch for 60 seconds.
Glare & Age
Do you have a couple more minutes? Fast forward to 18:00 minutes and watch until 20:30 minutes.
About Dr. Bob Adams
C&W Energy Solutions was formed in 2011 as a spin off from Chips and Wafers, Inc. (C&W), a company established by Dr. Robert Adams, PhD. in 1982. After graduating from Brown University, Dr. Adams joined Texas Instruments and then Motorola where he was involved in R&D for new LED and microwave devices.
C&W focuses on night friendly / environmentally friendly LED technology for street lighting and other outdoor applications. The company website: www.cwenergyusa.com
The City recently installed some outdoor LED lighting with a color temperature of 3,000k. That meets the minimum requirement of the International Dark Sky Association (IDA), but it is still a pretty bright white light compared to High Pressure Sodium lighting, because of the amount of blue light generated.
The lens creates a warmer yellow to orange light, essentially turning the LED into a “filtered” LED (FLED).
We wanted to see how effective the amber lens is at reducing blue light. That’s the part of the light spectrum that creates problems. So, Nathan Dupre and Paul Andrews spent a few nights collecting, among other things, the color temperature of lights around Ivins, with and without the amber lens. Then Nathan downloaded the results and analyzed them. Here’s a look at some of his findings.
The charts below show that the amber lens almost completely eliminates the blue portion of the spectrum and most of the green as well for all types of lighting. Eliminating blue goes a long way towards reducing glare and creates a warmer, healthier, more comfortable light.
High Pressure Sodium (HPS) lights have very little blue in their spectrum, even without the amber lens. The color temperature of the HPS lights Nathan measured were around 1,800k. Adding the amber lens didn’t do much, because there is so little blue in the spectrum anyway. For example, one light he tested dropped from 1,800k to 1,630k when the amber lens was used.
This warm light has been a common outdoor lighting source for decades. But because they are much less energy efficient than LEDs, they are gradually being phased out all around the country. The result is that the warm outdoor lighting we have been used to seeing for decades is being replaced by colder, whiter LEDs that create all kinds of problems.
Although LEDs are much more energy efficient, that benefit comes at a cost. They pump out a lot of blue light. Lower color temperatures generate less blue, but all “untreated” LEDs produce blue light. The LED in the chart above has a color temperature of close to 4,000k. When you add the amber lens the temperature drops to just 1,800k.
The addition of the amber lens creates a warmer light with less glare and virtually eliminates harmful blue light. That sounds terrific, so what’s the catch?
An Illuminating Study
In addition to measuring the color temperature of city lighting, Nathan also measured the illumination of the lights, with and without the amber lens. He found that adding the lens to High Pressure Sodium lights did not reduce illumination very much because this light doesn’t have much blue in its spectrum to begin with. So although the amber lens does not reduce illumination very much, there’s really no added value from using the lens because there’s not much blue light to deal with.
But LEDs are a different matter. They have a lot of blue light which the amber lens eliminates. The lens we were using also eliminates a lot of the green portion of the spectrum. The result is the amber lens cuts illumination almost in half.
Using a lens to modify the color temperature of LEDs and reduce blue light is a good solution and a worthy goal. We’ve just started to research the illumination issue, but it appears it is possible to filter the LED to achieve that goal but maintain 80% to 90% of the illumination. That would be ideal.
We plan to run some tests on possible solutions in the next week and will let you know what we find. Nathan’s research turned up some other important information. We will share these issues later this week in another posting.
Join us
We have lot more research planned, so if you would like to join our Technical Committee we would appreciate the extra brainpower. Just send us an email from the Contact Us page.
Rob Roush, the developer of the Red Desert subdivision in Ivins, contacted us last month because he was interested in making his development next to Red Mountain as dark sky friendly as possible. He also helped us on our first nighttime outing to measure the color temperature of lights in the City.
Over the past month or so, we exchanged a number of emails and discussed outdoor lighting issues he was dealing with in drafting his CC&Rs. Rob recently filed CC&Rs and sent us a copy. Rob had clearly done a lot of homework.
Red Desert’s CC&Rs are more restrictive than out current outdoor lighting ordinance. And they are more restrictive than the International Dark Sky Association (IDA) requires for communities seeking certification as Dark Sky Communities.
For example, our current ordinance allows the color temperature of outdoor lighting to be has high as 4,000 degrees kelvin. That’s too high and the City has plans to reduce that requirement to 3,000k or lower. IDA requires a maximum of 3,000k. Rob’s CC&Rs requires a range between 2,200k and 3,000k with a target of 2,700k.
Red Mountain as seen in unusual February snow from the Red Desert development site
IDA also requires properties limit the total amount of outdoor lighting. Our existing ordinance doesn’t really address that, it’s a newer concept in outdoor lighting circles. Red Desert’s CC&Rs not only address overall limits, they also set a maximum amount of lumens for each type of outdoor lighting use. And Rob’s CC&Rs are not only more protective about shielding lights than our current ordinance, they are more protective than IDA requires.
Thank you Rob for taking the efforts of our Ivins Night Sky Initiative to heart.
For more information about night sky friendly lighting, projects we are working on, upcoming events, or inquiring about getting involved, Contact Us.
The City of Ivins is trying something interesting with its outdoor lighting that, at least so far, we have not found other cities doing. The City has installed some lighting where the color temperature of the new light source is 3,000 degrees Kelvin.
Okay, that’s not the interesting part, please be patient. Lights with color temperatures below 3,000k are considered “warmer” and friendlier. A lot of older street lighting in the City has color temperatures well below 3,000k. That lighting has less glare, which is not only a safety plus, it is a big help for aging eyes. But lights with color temperatures at 3,000k are still pretty bright and white.
So, to improve the quality of the light, the City is fitting some of these 3,000k light sources with an amber lens. Nothing earth-shattering, just a simple plastic disc with an orange color.
But the amber lens changes the color of light that passes through it. We expect it helps to lower the color temperature of “colder” LEDs, making them friendlier and reducing troublesome glare.
Now that we have an amber lens we can test it with a spectrometer to see just how much of an impact it has on the color temperature of a light. We’ll let you know what we find out.
The color temperature of outdoor lighting has become a big deal in the past few years. LED technology has given us incredible energy efficiency. But more and more we are learning that this benefit comes at a cost: Too much glare, too bright, to much harmful blue wavelength emissions, and more. The old technology these LEDs are replacing, low- and high-pressure sodium lights, don’t have any of those problems.
The current outdoor lighting ordinance in Ivins sets a maximum color temperature of 4,000 degrees kelvin. Our ordinance is very dark sky friendly, and at the time it was implemented in 2007 it was probably a model of dark sky friendliness.
But time moves on. The “gold standard” today is to install lighting with a color temperature no more than 3,000 degrees kelvin. That is the requirement for designation as a Dark Sky Community by the International Dark Sky Association (IDA).
But some argue that 3,000k is still too high. For more information, see articles by Christian Luginbuhl, a retired scientist from the United States Naval Observatory in Flagstaff at the Flagstaff Dark Skies Coalition.
So, last night we went out to measure the color temperature of some outdoor lighting in Ivins. We were accompanied by Rob Roush of Red Earth Development. He is developing the Red Desert subdivision in Ivins next to the Reserve. He contacted us last month because he wants to maximize the dark sky friendliness of his project and has been searching for answers about appropriate color temperatures for his development’s outdoor lighting.
Technological improvements are great, but they can create more work, especially for those who pay attention. Color temperature is something nobody ever had to pay much attention to.
First, a disclaimer. Our outing last night is just a preliminary step. We need to do a lot more research, especially since the results we got raised some questions. But it was eye-opening.
We used a high-end spectrometer, the AsenseTek Lighting Passport. It’s an expensive little device that costs about $2,000. It communicates with an app on your cellphone. We were fortunate to be able to borrow it from IDA.
We measured some of the bollards on the west side of Rocky Vista University on 200 N. The spectrometer reading as under 1,600k for these. We’ll have to doublecheck with the City, but we believe the light source is an LED rated at well over 2000k.
City staff told us they added a “lens” to these lights that seems to lower the color temperature. But that’s still a big difference. It may be caused by the light source bouncing off a bowl shaped dome, and the dome’s color lowering the color temperature. Well, there’s some homework.
The color temperature of one of the city’s cobra lights was 1,851k. The light source in cobras is typically high pressure sodium. But they are slowly being replaced by LEDs.
We measured a number of other lights and got similarly low color temperature readings. Maybe the app we downloaded didn’t like our android phone. So Rob downloaded the app on his iPhone. He got the same readings.
For example, the newer post top lantern lights the City is installing were around 1,800k using both phones. We were expecting higher readings.
Maybe the AsenseTek spectrometer was giving us incorrect readings. That seemed unlikely. It’s an expensive, professional device.
But we were still concerned. Maybe we were measuring incorrectly. We tested that by taking a meter reading right next to the light source and a reading a number of feet away from the light source. We got the same result. That’s how it should be. We are measuring the color temperature of the light, not the amount of light, or illumination.
So we continued. The Veterans Center has parking lot lights that read just over 1,700k. These appear to be sodium lights. And it looks like a few were fluorescent, which came in at close to 3,000k. These readings made sense.
Similarly, the parking lot lights at Rocky Vista University registered around 4,000k. That also made sense. These are LED lights and our current ordinance allows lighting up to 4,000k. We found other parking lot lighting that had even higher kelvin readings, some close to 5,000k and some even higher. These were probably installations that predated our current ordinance.
Why go to all this effort? If we are going to recommend changes to the city’s outdoor lighting ordinance, we need to understand what lighting in the city might look like in the future.
This was a first step, and it certainly wasn’t a giant leap for Ivinkind, but at least it’s a start. We have some homework to do with IDA, AsenseTek, and the City.
If you have any expertise in lighting issues, we would value your input. Let us know if you are willing to help by emailing us from the Contact us page.
