Lam Partners has committed to buying 100% clean electricity for its Cambridge office through the City of Cambridge's new Community Electricity program. This program offers an option to pay a higher rate and purchase 100% of your electricity from renewable energy projects in New England.
This decision was made with strong support from the whole team at Lam Partners, expressing our commitment to reducing the carbon footprint of our operations, and our City.
Cambridge Community Electricity is an electricity aggregation program, a form of group purchasing in which a city or town uses the bulk buying power of the entire community to negotiate an electricity supply price for everyone. The program purchases renewable energy certificates (or RECs) to integrate renewable energy into the City’s electricity supply. With the Cambridge Community Electricity program, Eversource will continue to deliver electricity to Cambridge, but the City will now use a competitive bid process to choose its own electricity supplier. For more information, go to: masspowerchoice.com/cambridge.
What’s in a light meter? How much do light meters vary? Are the tried and true really as true as we believe?
We decided to explore these questions by challenging our meters, old a new, to a performance test. We digitally controlled light levels in our illuminance testing facility and introduced light situations from powerful LED blow-out down to tightly sealed interior darkness. Lam Labs looked at traditional to contemporary illuminance measuring devices, including the Lumu smartphone plug-in meter and its app, the firm’s trusty standby (a Minolta T-10) and a chunky brown General Electric 214 model circa 1960. Lets see how they stacked up.
- Most results remain consistent, and their agreement indicates accuracy – however this was most true in illuminance levels from 0-20 footcandles. Results diverge and become increasingly disparate as the tested illuminance level rises.
- The Lam Partner’s standby, the Minolta, T-10 ran largely parallel to the new, high-tech Lumu. New technology and trusted but older technology agree on light levels…proof that different generations can see eye to eye.
- The older GE 214 ran high for several tests, pulling the mean average up with it. If we ignore this model, there is a larger degree of consistency between all results.
If we set the reliable Minolta-T10 as our baseline, how much do the others deviate from its results? The following graphs explain.
This graph shows each meter’s percentage of variance above or below the standard Minolta T-10 during each light situation.
The HS 1010 runs high consistently, with a 2-7% range for deviation. The Minolta TL-1 runs low consistently, with more variance – between 0 and 9% – and this range gives slightly more reason for distrust.
The Lulu is highly sensitive at lower light levels, suggesting perhaps it picks up light from the iphone screen to which it is attached – which of course can vary by setting for phone model. Alternatively, the Lumu may be finely tuned enough to sense tiny light leaks around doorways in the testing facility.
The GE 214 runs high overall, but reads significantly higher at increased light levels – not a typical trend and therefore this outlier can be tossed out of the runnings for accuracy.
Dr Meter also runs low, but with more uniform results than other meters, from around 2-6% variance, making it a reliable 2nd or 3rd choice after the Minolta T-10 and Lumu which have very similar performance.
The greatest variances – even larger than this graph would comfortably accommodate – are seen at lowest light levels. Those first few moments when a meter is exposed to light are unpredictable, indicating they all could use extra time for calibration and to reach peak performance, and multiple readings until consistent sequential readings are reached.
THE LIGHT METER ACCURACY AWARD GOES TO:
1st Minolta T-10 & Lumu
2nd Dr. Meter
4th Minolta TL-1
5th GE 214
This study was performed by Brittany Lynch and Piper Ainsley in September 2016.
Is LED Street Lighting Bad for Your Health?
Misinterpretation of AMA report distracts from the real problems
The American Medical Association’s (AMA) recently issued report, “Human and Environmental Effects of Light Emitting Diode (LED) Community Lighting,” highlights many important issues regarding the implementation of street lighting to avoid negative environmental and health effects.
Unfortunately, on the subject of potential negative health effects of LED street lighting, the report has been misinterpreted by online media and even by the International Dark-Sky Association (IDA). The report has been boiled down to a sound bite along the lines of: “AMA says LED streetlights are bad for your health! (unless they are 3000K)”. This is really unfortunate, not just because it’s wrong, but because it puts attention solely on the issue of color temperature, distracting from the other very important issues raised in the report.
Jumping to Conclusions
Here are some examples of misinterpretations and misstatements.
- From NPR:
- …Not true. The AMA report does not say this.
- From takepart.com:
LED Streetlights Are Good for the Earth, Bad for Humans and Wildlife
“Studies have shown that white LED streetlights are five times more powerful at suppressing circadian rhythms than the high-pressure sodium lights they are replacing, the AMA noted.”
- …Not true. The AMA report does not say this.
- From the International Dark Sky Association blog:
- “Not only is blue-rich white LED street lighting five times more disruptive to our sleep cycle than conventional street lighting, according to the report…”
- …Not true. The AMA report does not say this, either.
What the AMA Really Says
Here is what the AMA report does say (emphasis added):
“It is estimated that a “white” LED lamp is at least 5 times more powerful in influencing circadian physiology than a high pressure sodium light based on melatonin suppression. Recent large surveys found that brighter residential nighttime lighting is associated with reduced sleep time, dissatisfaction with sleep quality, nighttime awakenings, excessive sleepiness, impaired daytime functioning, and obesity. Thus, white LED street lighting patterns also could contribute to the risk of chronic disease in the populations of cities in which they have been installed.
Measurements at street level from white LED street lamps are needed to more accurately assess the potential circadian impact of evening/nighttime exposure to these lights.”
All the AMA report is saying is that it has been estimated that an LED source (of undefined color temperature) could potentially have 5 times the melatonin-suppressing effect as a high-pressure sodium source. (High-pressure sodium was the lamp source commonly used in street lighting before the arrival of LED). What the report neglects to mention is that the exposure to these two sources would have to be of sufficient intensity and duration to have any effect at all. It cites no evidence that the intensity and duration of exposure typically experienced from street lighting is sufficient to have any melatonin-suppressing effect.
The “recent large surveys” mentioned in the report refer to two epidemiological studies which looked for correlations between outdoor light at night, and obesity and sleep disruption. The measurement of outdoor light at night was derived from satellite imagery, with no information on spectral content (“color”) of the light. Since the satellite data used in the studies was from 2001 to 2009, the lighting was most likely high-pressure sodium, and certainly not LED. The studies show an association between obesity and sleep disruption and the level of outdoor lighting, but no causal effect. But even if a causal connection was proven, it can’t be connected to “blue” light, and would have been a problem long before the advent of LED street lighting.
In this RPI/LRC study, computer modeling was used to predict the potential melatonin-suppressing effect of exposure to street lights. The authors estimate that if you stood on the street under 5900K (high “blue” content) LED street lighting for one hour you might experience a small effect.
The AMA report also notes that the percentage of “blue” light in a 4000K LED source is 29%, vs. 21% for a 3000K LED source. Even if exposure to LED streetlights did have a negative health effect, 3000K instead of 4000K probably would not make much difference, based on the marginal difference in percentage of “blue” light.
And most importantly, the AMA says that further study is needed to assess potential health impacts from street lighting. Agreed!
Is Warmer Better?
There are reasons to use 3000K sources in outdoor lighting, such as reduced sky glow (see Ian Ashdown’s Color Temperature and Outdoor Lighting), glare reduction, design aesthetics, or personal/community preference. Until recently, there was a reason to not use 3000K LED, due to significantly lower energy efficacy compared to 4000K LED. But with recent improvements in LED technology, this difference in efficacy is very small, negating the disadvantage.
But, there are also possible reasons to use 4000K sources in some outdoor lighting applications. A study by Clanton & Associates and VTTI showed that 4000K LED street lighting resulted in significantly better ability of drivers to detect pedestrians at greater distances, compared to the other higher and lower color temperatures tested. This might make 4000K the best choice from a safety standpoint on streets with pedestrians and cyclists. Research from RPI shows that perceived outdoor scene brightness is higher with higher color-temperature sources. If you accept the premise that you need less light (fewer photopic lumens) from 4000K street lighting than from 3000K street lighting, then a 4000K street lighting system could use less energy, and create less light pollution than a 3000K system…possibly.
It’s a complex problem with no simple answer. So let’s use 3000K sources for all the good reasons, but not for some presumed public health benefit.
Let’s Keep Our Eyes on the Ball
We should be concentrating our efforts on reducing overall light levels, putting the light only where it’s needed, and controlling glare. This is where we can have a real impact on reducing light pollution and negative environmental impact. I'd hate to see a future where all the streetlights are 3000K, but we are still over-lighting our streets and parking lots.
And when it comes to the effects of light on health, we should be focusing our attention on interior lighting, lighting for shift workers, and light from display screens. This is where there is solid evidence that the quantity and the “color” of light can have negative (and positive) health effects.
For other perspectives on this issue, read the comments from the US Department of Energy and The National Electrical Manufacturers Association, and the detailed analysis from The Lighting Research Center at RPI.
To the AMA: Please Hire a Fact-Checker
A final comment on one blatant error in the AMA report, that is of special interest to me—the report says: “In Cambridge, MA, 4000K lighting with dimming controls was installed to mitigate the harsh blue-rich lighting late at night.”
The truth is that the adaptive dimming system was planned from the beginning of the project to reduce energy use and limit light pollution. The decision to use the adaptive dimming system had nothing to do with mitigating “harsh blue-rich lighting”. I know this because I was intimately involved with the design of the conversion of Cambridge’s street lighting to LED.
The Cambridge lighting control system is still the largest street lighting adaptive dimming system in the US, as far as I know, and is significantly reducing light pollution in our City. Other cities should be following Cambridge’s well-studied lead, and not take media sound bites or one line excerpts from this AMA report as accurate recommendations on how to minimize negative environmental or human health effects.
In our latest Lam Labs initiative, Lam’s Advanced Computing Team has implemented a high-density GPU array to run NVIDIA’s Iray software, allowing designers to tap into incredible rendering capabilities for almost-real-time realistic and accurate visualization of designs, using real fixture photometrics. The team recently spent time discussing capabilities with NVIDIA’s Iray team, who noted that Lam’s capabilities are “a truly impressive and innovative use of their software for architectural visualization”.
Below are a selection of visualizations the team has produced for various projects, ranging from design studies employing false color illuminance distributions to “light path expressions”, allowing for post-process dimming or color-changing using Adobe After Effects.
The new behemoth GPU array, located in Lam Partners’ secret lair.
Short movies show the feeling of spaces, or the effects of dynamic media displays:
Using ‘lightpath expressions’ designers can model the effects of dynamic lighting arrays:
Daylighting visualizations can all-but-replace physical model studies on the heliodon
Slide the slider to change the time of day
Still images with advanced materials and photometric lighting can quickly show designers how spaces will feel and be illuminated – switching to false color views helps verify appropriate light levels, or cutting sections through spaces to peer inside.
On November 17, 2015, Glenn Heinmiller presented at the 2015 U.S. Department of Energy Solid-State Lighting Technology Development Workshop in Portland, Oregon. This presentation was part of a session titled "Remaining Challenges: LED Street Lighting", and draws from lessons learned during the LED streetlight conversion underway in Cambridge, Massachusetts. Glenn provides an informed view of the benefits and challenges involved with implementing this emerging technology.
Designers Maggie Golden and Jack Risser recently flew across the pond to represent Lam Partners at this year’s DIVA Day conference hosted at the Architectural Association in London. Attending both the conference and training sessions provided an insightful look into the professional world of commercial daylighting. The Solemma team, including former Lam employee Kera Lagios, presented the new version of DIVA 4.0, with some very cool new grasshopper tools, and integration with the energy modeling program ArchSim. Presentations from various international teams shared their work and discussed the past, present, and future of daylighting design.
Some Highlights of the conference:
Anne Iversen at Henning Larsen presented “Optimizing a Façade for an Arid Climate.” Although the design approach and style were interesting, the biggest takeaway was the importance of working through iterations. Optimization processes allow you to learn from each iteration, and ultimately evoke the best optimization from all aspects of design. The process also helps designers develop daylight intuition for future projects.
Another interesting presentation came from Reinier Zeldenrust of Atelier Ten, titled “Twenty-Five Years of Atelier Ten.” While the presentation read like a history of the company – it also portrayed the history and potential futures of daylighting design. Zeldenrust artfully illustrated how far the design community has come in daylighting and integrated design. Though softwares like DIVA, Ladybug, Honeybee, and many more, the act of daylighting design gets easier each year; however the basics are as important as ever. The future holds integration with of energy design, and visual representations such as virtual reality.
We’re excited to take full advantage of the new DIVA build at Lam Partners, and through Lam Labs continue to push the limits on daylighting design processes with emphasis on integration of thermal comfort and energy considerations, with quality of light and visual comfort. We continue to research cutting edge visualizations that not only allow architecture firms to visualize daylighting designs but also allow for custom components to create real-time collaboration with architecture firms through the design.
Jack Risser has developed a slick visualizer to show off various visualization strategies Lam Daylighting designers create, replacing the decades-old techniques of physical model heliodon studies. Design studies were performed by Dan Weissman and Maggie Golden.