LightNOW

The most eye-catching building on the Denver skyline, the Wells Fargo Center, has become even more distinct, thanks to a stunning makeover by the Manhattan-based experiential design firm ESI Design. The three-year project, featuring an eight-story digital LED installation in the building’s glass atrium, opens this month.

The Wells Fargo Center, designed by Philip Johnson in 1983, is known as the “Cash Register Building” because of its unique shape that resembles an antique cash register. Inside the building’s immense street-level glass atrium, which echoes the cash register shape of the roof, ESI designed five 86-foot floor-to-ceiling LED columns that are six times the resolution of normal HD. The monolithic screens display dynamic media inspired by the Mile High City’s natural wonders.

ESI’s team of media designers and animators conceived the inventive content to fully exploit the epic physical scale of the space. The mix of pre-produced and generative media includes:

• A flock of birds that are animated in real-time (as opposed to a video file). A total of 3,600 birds are always deciding what to do next, at 60fps, based on algorithmic rules of behavior. They can fly for hours and their flight pattern never repeats.

• Floor-to-ceiling waterfalls built in 3D, containing 15 million polygons each that have variations of speed and volume and move across the wall in different paths depending on the direction of the wind outside.

• A grove of trees—modeled, textured, and animated individually in 3D—change with the time of day and season, such as a change in color in the fall and the loss of leaves in the winter.
• Colorful ink drops swirling in slow-motion using video footage of a tiny plastic fish tank, filmed in a studio in Hoboken.

• Colorado mountainscapes that are actually mosaics of thousands of Instagram photos, drawn from an ever-growing library of local, user-generated images. Each Instagram show is built up of 8 different mosaics (each with a different tile size and containing thousands of images). From a distance, the effect for the viewer is like looking through slats in an enormous fence to the majestic Colorado landscape beyond the skyscraper’s walls.

The vibrant media installation is visible from outside through the glass atrium, breathing new life into the surrounding streetscape and drawing passersby into an experience that promises to become a new Denver attraction for tourists and locals alike.

Check it out here:

A recent contribution to tED Magazine. Reprinted with permission.

The Department of Energy (DOE) recently updated its bi-annual report, Energy Savings Forecast of Solid-State Lighting in General Illumination Applications. This major report models adoption of LEDs in the U.S. general lighting market.

In 2015, LED products comprised an estimated 6 percent of the total installed stock, up from 3 percent in 2013. DOE forecasts 30 percent penetration by 2020 and 59 percent penetration by 2025. The forecast is partly based on a revised assumed renovation rate, which DOE increased from 5 to 10 percent. This recognizes the growing market for lighting upgrades in existing construction.

The outdoor stationary market leads in LED penetration, with estimated 19 percent penetration in 2015 and projected 57 percent by 2020. The commercial market is also growing, with an estimated 12 percent penetration in 2015 and projected 36 percent by 2020.

Strongest penetration has occurred in three markets:

• A-type lamps, which accounted for 46 percent of installed LED lighting and 14 percent of the energy savings;

• directional lighting, 18 percent of installed LED lighting and 29 percent of the energy savings; and

• linear lighting, 16 percent of installed LED lighting and 20 percent of the energy savings.

By 2020, annual energy savings from LED lighting will reach about 293 MWh. While direct load reduction will generate the majority of these energy savings, lighting controls will account for a significant portion. By 2035, DOE expects connected lighting and lighting controls to generate one-third of all energy savings.

Let’s look at three submarkets in detail—linear, low- and high-bay, and area and roadway lighting:

• Linear lighting: High-performance LED lighting will have a strong impact on this market. Current penetration is 3 percent. Though fluorescent systems offer efficacies as high as 90 lumens/W, both linear LED luminaires and replacement lamps already exceed that and are continually improving. By 2020, LED luminaires and lamps will penetrate 16 percent of the linear luminaire stock by 2020, according to DOE.

• Low- and high-bay lighting: Fluorescent lighting against dominates in this increasingly popular market. Again, LED is poised for rapid growth. LED luminaires penetrated about 6 percent of the installed stock in 2015, while high-wattage LED retrofit lamps represented less than one percent. Penetration is expected to increase to 38 percent by 2020 (39 percent commercial, 35 percent industrial), according to DOE.

• Area and roadway lighting: LEDs are well suited to these applications because of the directionality, durability and longevity of the light source. Metal halide and high-pressure sodium dominate this market, but LED has already achieved a significant 21 percent share of the installed base. DOE forecasted penetration to increase to 66 percent by 2020. DOE noted that as with other markets, there is an initial uptake in LED replacement lamps followed by their decline relative to LED luminaires.

Click here to download the report.

LED penetration in the installed lighting stock by general lighting market, 2015-2035.

Laser diodes, a high-efficiency incandescent, bioLED phosphors, cheaper quantum dots and nanowires. My contribution to August issue of ELECTRICAL CONTRACTOR reviews several intriguing new developments and research directions in lighting technology.

Read it here.

Earlier this year, the OLED Coalition and the California Lighting Technology Center hosted the OLED Lighting Workshop. Peter Ngai of Acuity Brands kicked off the event with a keynote.

Click here to download the presentation.

SYLVANIA Vintage LED Lamps offer an antique amber glow with a color temperature of 2200K. SYLVANIA ULTRA LED Filament Lamps have a classic clear glass style with a color temperature of 2700K and are dimmable down to 10%.

Both lamp families offer the incandescent form factor and illumination and are available in A19, ST19, B10, A15 and G25 versions. They are rated at 15,000 hours (L70) and are well-suited for table lamps, wall sconces, chandeliers and outdoor lanterns.

Click here to learn more.

Johannes Vermeer was a Dutch painter in the 1600s who mainly produced paintings of domestic interior scenes. He is most celebrated for his extraordinary use of light in his paintings. Light, typically daylight, permeates his scenes, beautifully rendering his subjects using light and shadow.

Check out this documentary about Vermeer’s work and his brilliant use of light, which distinguishes his work among the greats.

DOE is offering a series of webinars on healthcare lighting. Both start at 1:00 PM EST and last for 60 minutes:

Tuesday, October 4: Evidence-Based Design for Healthcare Lighting: Where’s the Evidence?
Presenters: Anjali Joseph, Clemson University, Robert Davis and Andrea Wilkerson, Pacific Northwest National Laboratory

The nonvisual effects of light have captured a lot of interest lately, as important new research on the topic emerges. But beyond the nonvisual effects of light, architectural lighting supports other important outcomes for caregivers and patients, addressing visual task needs and providing for overall comfort and wellbeing. This webinar will present results from a major literature review summarizing published evidence for the benefits of high-quality healthcare lighting reported in recent research. It will also discuss how future research can provide even stronger evidence to link the design of healthcare facilities to a holistic set of human needs. The presenters will describe the major findings from recent research related to lighting for healthcare applications, explain how research methodology can be improved for future application to healthcare design, evaluate how the principles derived from recent research can be applied to an evidence-based design process that addresses a holistic set of visual and nonvisual human needs, and compare the benefits and drawbacks of emerging SSL technologies for addressing the needs of patients and caregivers in healthcare applications.

Click here to learn more or register.

Tuesday, October 18: Tuning the Light in Senior Care
Presenters: Connie Samla, Sacramento Municipal Utility District, Robert Davis and Andrea Wilkerson, Pacific Northwest National Laboratory

DOE collaborated with the Sacramento (CA) Municipal Utility District (SMUD) and the ACC Care Center in Sacramento to evaluate a trial installation of LED lighting systems, in preparation for a planned expansion and renovation at ACC. New LED lighting systems, including white-tunable luminaires and amber night lighting, were installed in two patient rooms, a central nurse station, corridor, family room, and administrative office. The systems were compared to the existing fluorescent systems in terms of their photometric performance and estimated energy use, and the ACC staff tracked behavioral and health measures before and after the installation. This webinar will share the results of the initial pilot study and how this has affected ACC’s future plans. The presenters will evaluate the results of the trial lighting systems (including energy, photometry, patient behavioral measures, and feedback from patients and caregivers), analyze several techniques for implementing amber LED lighting for nighttime navigation, describe the control scripts used for tuning the LED lighting spectrum and output based on the desired sleep cycle effects at different times of the day, and explain the challenges faced when installing these solutions in existing buildings.

Click here to learn more or register.

Republication of Postings from the U.S. Department of Energy (DOE) Solid-State Lighting Program by Jim Brodrick, SSL Program Manager, U.S. Department of Energy

Not too long ago, solid-state lighting was more of an intriguing possibility than a practical solution. The majority of SSL products on the market back then were all over the map in terms of performance, and those that could measure up to the incumbents were considered paragons of success. The technology has come a long way since then, to the point where today you can find competitive SSL products for most lighting applications. SSL products can outperform their conventional counterparts on many parameters — not just efficacy and total cost of ownership, but also color quality, light distribution, and new features such as engineered spectrum, connectivity, and novel form factors.

But in the flush of such rapid and still-growing success, the considerable array of choices offered by SSL is in danger of being overlooked. All other lighting technologies are more or less “monolithic,” in the sense that their characteristics are severely limited in scope by the very nature of the technologies themselves. For example, the ability to tune the spectral content of high-pressure sodium lighting is quite limited. But with semiconductor-based SSL, many of these historic limitations don’t apply, enabling an astonishingly versatile lighting technology that can be shaped in a multitude of different ways.

Those different ways are not always immediately apparent, however, because the majority of SSL products are designed as direct replacements for conventional incumbents. Also, these features may add cost — especially at this relatively early stage of the technology. As a result, manufacturers often intentionally sacrifice performance on one or more parameters, in favor of keeping prices low. But the choices are available and will continue to grow, as consumers come to appreciate features such as very high efficacy, extended lifetimes, tailored color, and connectivity.

To get an idea of the range of choices available in LED lighting products, one has only to look at the LED Lighting Facts® database. There, you’ll find products that run the entire CCT gamut, from below 2500K to over 7000K. In terms of color rendering, you’ll find several hundred listed products with a CRI ≥ 95, for those applications that demand that kind of super-performance. LED products can also be tuned to optimize TM-30 fidelity and gamut combinations, depending on the demands of the application. And there are ranges of efficacies within product types, with the most efficient products exceeding 150 lm/W.

The point here is that LED lighting technology has become a platform that gives users a tremendous number of options. As the technology has improved, manufacturers have had more cost and design headroom to add features, characteristics, and capabilities that weren’t possible before — either because they couldn’t be achieved, or because they would have been inordinately expensive. A major factor in this development has been continued improvements in efficiency, which make it possible to use fewer LEDs to get the same output, thus lowering the price and opening up physical space for the integration of other features.

Manufacturers can mix and match capabilities, in virtually any combination; e.g., one product can have high efficacy but only fair color rendering, while another can have excellent color rendering but lower efficacy. Products can even be engineered to have spectral power distributions that match specific applications, or that can be dynamically changed — whether to highlight merchandise, to enhance the production or nutritional value of crops, or to improve health and productivity. And products can also be designed so that light output and distribution can be dynamically changed.

In other words, the legacy of one-dimensional thinking about lighting was driven by the limitations of conventional technologies, and doesn’t apply to SSL, which offers enormous flexibility and a wide array of choices. So those who assume that choosing an energy-saving lighting product means compromising on performance should wake up and smell the LEDs.

I recently had the pleasure of interviewing Ethan Biery, LED Engineering Leader, Lutron Electronics. The topic: flicker. I’m happy to share his responses with you here. The interview informed an article I wrote for the December 2016 issue of ELECTRICAL CONTRACTOR.

DiLouie: In your opinion, how big a problem is LED product flicker in the lighting industry as of 2016? What types of products (lamps versus luminaires, high- versus low-end products) are most likely to exhibit flicker? What types of applications are most likely to experience visual and/or stroboscopic flicker?

Biery: All light sources, including LED and incandescent, inherently provide stable light output when provided with a stable power source, but most real-world power is not perfectly stable, which is why flicker was a problem even before LEDs. However, LED light sources can be more prone to showing Temporal Light Artifacts (TLA) than other sources due to their fast response time.

The likelihood that an LED will flicker (visible or stroboscopic) is directly related to the quality of the driver, and indirectly related to the quality of the power source. While customers have little control over their building power quality, they do have control over the quality of the driver. Generally speaking, lower-cost (and lower-size) drivers are more likely to exhibit flicker, especially under noisy power conditions, because they may lack the necessary filtering to ensure stable power is delivered to the LEDs.

Highly detail-based tasks, especially those illuminated with a single light source (such as reading by the light of a bedside lamp), or applications with low light levels, are more likely to generate complaints around visible flicker. Tasks that involve motion or moving objects are more likely to experience the effects of stroboscopic flicker. Overall, however, the effects of flicker are highly dependent on the observer (and, like the sound of a dripping faucet, once flicker is detected, it becomes difficult to ignore).

DiLouie: How often is flicker an issue of either 1) LED lighting systems operating at full output or 2) LED lighting systems either dimming or reaching a certain dim level? Which is the greater concern?

Biery: The eye is naturally more sensitive to fluctuations in light when light levels are low, so any instability of the light is more likely to be seen as visible flicker when dimming to low levels (such as those below about 10%). Given the right environment, the effects of stroboscopic flicker can be seen at any light level.

DiLouie: How does visual and/or stroboscopic flicker manifest in traditional light sources and in LED light sources? What is it about the LED source that makes flicker a significant issue?

Biery: What determines whether or not TLA will occur is the quality of the power signal delivered to the light source, combined with how tolerant the light source is to any fluctuations in power. For example, high frequency electronic ballasts virtually eliminated the flicker problem that was once commonly experienced with low-frequency magnetic ballasts. In other words, merely changing the quality of the power source (the output of the ballast going from 60Hz to tens of kilohertz) greatly decreased the presence of flicker, although the lamps themselves remained unchanged.

Like all other sources, LEDs produce light output that is inherently very stable when fed with a stable power source. Because LEDs are very fast-acting, and any fluctuation in the power source to the LED will become an instantaneous fluctuation in the light output — this is what we see as flicker.

In contrast to LEDs, incandescent lamps are particularly tolerant of fluctuations in their power quality because their hot filament filters out many fluctuations (although some measureable amount of modulation is still present at a 60Hz line frequency). As a result, LEDs are more likely to show flicker then incandescent lamps are under the same conditions.

DiLouie: What detailed recommendations should electrical contractors follow to minimize flicker when selecting an LED driver?

Biery: When using fixtures, be sure to choose one with a high-quality driver. The LED driver plays a very significant role in delivering flicker-free, high-quality dimming performance. Less expensive, less complex drivers generally have fewer filtering components and use analog instead of digital circuitry, making them more susceptible to undesirable modulation and external electrical interference.

In their push to lower-priced designs, many screw-in retrofit lamps have reduced the amount of filtering done in their integral drivers, making them especially susceptible to flicker from power line fluctuations.

Also, be very wary of metrics. There is no established method for measuring flicker that completely captures all the aspects of TLA, and different applications can tolerate different levels of TLA. Simply citing an inadequate metric (such as Flicker Index or Percent Flicker) or seeing a spec sheet that says “flicker free!” won’t assure you a satisfying end result.

DiLouie: What are common causes of flicker that are external to the LED lighting system, such as the power supply and connected dimming controls? Why and how do these causes produce flicker?

Biery: Outside of the lamp or fixture, flicker can result from noise being introduced through power or control wires. For example, electrical noise generated from large motors or other power-hungry devices can reach a driver, pass through it, and cause flicker on the output. That same electrical noise may also introduce instability into a phase-cut dimmer waveform, causing flicker. Finally, even for drivers that use analog low-voltage control signals (such as 0-10V), noise coupled into the control wires can induce flickering from some drivers.

By nature, digital controls will consistently deliver higher performance than analog controls. Digital controls provide a more precise signal whose quality is less affected by noise and external interference, and therefore less likely to result in interference-induced TLA.

Large-scale installations of LEDs, especially in commercial spaces, often demonstrate the weakness of existing analog control technologies such as phase control and 0-10V. Not only are analog controls prone to compatibility problems and interference, but they don’t deliver the sophisticated features that building managers expect from their lighting control

DiLouie: What detailed recommendations should electrical contractors follow to minimize flicker when pairing lighting controls with LED lighting systems?

Biery: First and foremost, keep in mind that the LED driver plays a very significant role in delivering flicker-free, high-quality dimming performance, and simpler drivers are often more prone to flicker. Less expensive drivers generally have fewer filtering components and use analog instead of digital circuitry, making them more prone to external electrical noise sources, which can manifest as flicker. (The same often holds true for retrofit LED lamps, which contain an integral LED driver.)

Use trusted manufacturers for fixtures, drivers, and controls, and stick to what has worked for you and your customers in the past.

Work with manufacturers who guarantee compatibility and performance between system components, such as drivers and control systems.

Use digital control rather than analog whenever possible. Digital controls are less prone to external noise and therefore less likely to result in interference-induced TLA.

Consider doing project mockups for larger jobs. This allows experiencing and evaluating a proposed lighting and control solution in real time and in the actual environment. Mockups reduce the risk of finding performance problems on an installed job, when remediation becomes extremely difficult and expensive.

Work with a quality manufacturer who demonstrates a commitment to testing thousands of driver, fixture, bulb, and control combinations for compatibility and performance (including flicker), and who makes those results public and easy to access. One such example is the Lutron LED Control Center of Excellence (www.lutron.com/ledtool).

DiLouie: What detailed recommendations should electrical contractors follow to minimize flicker that may be produced by other external sources such as voltage fluctuations on the power line? What applications present the greatest risk?

Biery: For new installations, contractors should follow the recommended practice of separating wiring (including neutral wires) between lighting and non-lighting loads as much as possible. Likewise, control signals (especially analog-based control signals, such as 0-10V and phase control) should be run separately from the high-current power wires that supply electrically noisy sources. Common sources of electrical noise are motors, including those found in elevators, compressors, and HVAC equipment.

DiLouie: How can electrical contractors test for flicker in the field? What specific testing can they undertake to evaluate potential installations?

Biery: Unfortunately, there are no good field-measurement techniques for measuring flicker as it corresponds to human perception. The best tool is still the eye of an experienced lighting professional.

DiLouie: What can electrical contractors do to mitigate flicker after installation, if anything? What is the basic troubleshooting process and typical remedies?

Biery: Mitigating flicker is best managed prior to installation by choosing compatible system components, and high quality drivers and controls. However, if flicker is experienced in the field, answering some basic troubleshooting questions may help narrow down the cause.

• Is the flicker always present, or it is intermittent? If intermittent, does the flicker correspond to any other activity (such as the motion of a nearby elevator)? Are all fixtures flickering, or just those in one particular area? Does the light source still flicker when moved to a different area of the building? These may all indicate the flicker is related to an external electrical noise source, which must be identified and mitigated.
• Is flicker only experienced at a particular light level, or at all light levels? This may indicate incompatibility with the lighting control being used.

DiLouie: What metrics are available to electrical contractors seeking to evaluate flicker potential of LED products?

Biery: Many lighting professionals are looking for an industry standard that definitively identifies acceptable levels of TLA (both flicker and stroboscopic effects), and can be applied in a wide variety of applications. At this time, however, it’s best to proceed with considerable caution because existing industry metrics for measuring and mitigating TLA remain limited and somewhat controversial.

Until researchers agree on a way to measure and replicate results that are consistent with human perception, while also controlling for all contributing factors, many lighting manufacturers and industry organizations are hesitant to recommend a particular standard or guideline.

DiLouie: What are the shortcomings of these metrics? What is the industry doing to develop suitable new metrics? How do you anticipate they will be used?

Biery: Most existing metrics have little correlation with the human perception of flicker, and therefore offer little insight as to whether or not the flicker will be visible in the end application.

Flicker is a scientific measurement and needs to be treated as such in developing design standards and identifying appropriate metrics. Both NEMA and the Department of Energy (DoE) are actively working to characterize TLA and measurement devices in hopes of developing metrics that are reproducible and account for the wide number of variables in general-purpose lighting applications.

For example, the DoE has recently tested existing flicker meters against a benchmark to provide specifiers and their customers with better guidelines and recommendations regarding measuring and accounting for basic flicker parameters in their projects (Click here to learn more.)

DiLouie: If you could tell the entire electrical industry just one thing about the flicker and LED lighting, what would it be?

Biery: TLA should certainly be taken seriously, as it can be a source of occupant discomfort and dissatisfaction, but until the industry reaches a consensus on a standard that accounts for all the variables in a lighting scenario, merely citing existing flicker metrics is probably not sufficient. Instead, work with high-quality, experienced manufacturers that will recommend, install, and support the right LED solution for your project. In the meantime, look for further updates on IES, CIE, and NEMA developments in flicker research. As an industry, we all look forward to a robust, reproducible, and accurate standard for measuring TLA.

Below is my contribution to the August issue of tED Magazine on the topic of lighting and health. Reprinted with permission.

For millions of years, sunrise and sunset set the human body clock, or circadian system. This system produces and regulates bodily functions such as sleep-wake cycles, body temperature and hormonal release based on 24-hour cycles, or circadian rhythms. These functions in turn are stimulated by light falling on specialized cells in the eye that convert it into neural signals.

In the modern age, humans spend the vast majority of their time indoors exposed to electric lighting systems designed primarily for vision. People also spend large amounts of time with mobile devices. This creates risks of circadian disruption that can affect health and well-bring.

“Research now tells us that a disrupted circadian system is connected to long-term health, productivity and behavioral problems such as fatigue, cancer, obesity, diabetes, depression, mood and sleep disorders, reduced physical and mental performance, and irritability,” says Bonnie Littman, President and CEO, USAI Lighting. “In essence, light is powerful and essential, and can and should be used for the betterment of human health and well-bring.”

As scientists advance our understanding of light and health, the lighting industry is beginning to experiment with practices and products that can be used to create more circadian-friendly environments.

“There is currently enough evidence to claim benefit for individual health and happiness,” says John Hollander, Director Brand Development, Hubbell Healthcare Solutions. “Where care has to be taken is claiming healing benefits or patient outcomes.”

What we know

The Lighting Research Center has identified four main characteristics that influence light’s impact on circadian health:

• Intensity: cumulative amount of light falling on the eye’s photoreceptors throughout the day—an issue of vertical, not horizontal, light levels. This may be the chief influence.
• Spectrum: wavelength of the light. Visual acuity is most responsive to “green” (medium-wavelength) light, while circadian regulation is most responsive to “blue” (short-wavelength) light. Meanwhile, “red” light can increase daytime and nighttime alertness, making it also important.
• Timing: when light and spectrum are received by the eye’s photoreceptors. A high intensity of blue light received in the morning will aid an early bedtime but can delay sleep if received in the evening.
• Duration: quantity of time of exposure. The circadian system responds slowly to light received throughout the day.

“We know with certainty that for normal populations, exposure to blue-rich light during the day supports optimal circadian health, and exposure to blue-rich light at night disrupts our circadian rhythms with negative consequences for sleep and health,” says Scott Roos, Vice President Product Design, Juno Lighting Group, an Acuity Brands company. “The ‘typical’ lighting scenario of working in a cool, brightly illuminated office during the day and a warmer, more dimly illuminated home environment during the evening is actually spot-on in terms of supporting good circadian health for normal populations.”

Healthcare and assisted-living facilities are considered solid early adopter opportunities for circadian lighting strategies. Image courtesy of USAI Lighting.

The devil in the details

Current research doesn’t connect health outcomes with specific lighting design strategies. Most research is conducted in laboratory conditions, and with average responses. Additionally, nighttime light exposure is as important as daytime exposure, and individual lifestyle trumps all of it.

The lighting industry understands that light and health are connected, and that lighting, as the application of light, can impact health. Practitioners have the basic understanding and tools they need to make lighting systems more circadian-friendly. They’re just not sure to what extent and for what percentage of people. And there’s currently no best practice.

“The science of illumination is expanding with varying experts’ views on applications and outcomes,” Littman says. “Creating new metrics to explain how light impacts our biological systems will be critical in realizing the promise that light has in its impact on health and productivity.”

Hollander recognizes that current research suggests some general guidelines but otherwise the industry is still learning. “There isn’t a recognized ‘prescription’ for the optimized spectrum, intensity, timing and duration,” he says. “It is very likely we will see a ‘prescription’ or template in the future with the equipment to support it.”

Ideal early applications include environments in which occupant activity and wake/sleep patterns are predictable, such as healthcare and assisted-living facilities. Roos says research is continuing and, along with the results of early adopter applications, will reveal recommended practices. He says: “Our knowledge base and ability to provide more concrete information will continue to increase.” By the time organizations such as the Illuminating Engineering Society publish a specific recommended practice, he adds, the basics of circadian lighting will be widely understood.

“Additional tools will be used to guide us,” says Littman. “There are new lighting metrics such as circadian light, circadian stimulus, melanopic lux and others that are emerging to guide lighting product development and lighting design practice.”

General guidelines

“Research has shown that by providing exposure to natural light throughout the day or electric illumination where the intensity and spectrum is adjusted for the time of day, individuals experience a more typical sleep/wake pattern,” Hollander says.

He points to research specifically recommending introduction of blue-rich light starting in the morning with an intensity of 30-40 vertical footcandles. The light would then transition to a warmer spectrum and lower light levels at late afternoon and into the evening. At home, intensity would then drop to 1-2 footcandles before total darkness at bedtime.

Looking at a typical commercial building with workers occupying it on a 9-5 schedule, several elements are needed in the lighting design. Since we are concerned with vertical illumination, the lighting must deliver sufficient light on vertical surfaces such as walls. Task lighting can efficiently provide high local vertical light levels. The lighting system must be properly controlled to automatically adjust intensity and optimally spectrum during the day on a schedule. Ideally, occupants will be exposed to daylight. If they don’t have access to daylight, they should be encouraged to take a 30-minute walk outside in daylight in the morning. Finally, they should be educated about good nighttime lighting practices.

Circadian lighting and LED sources with intelligent control are ideally matched. “We are starting to characterize the circadian content of various light sources, which is different than the visual amount of light as measured in lumens or footcandles,” Roos says. “Understanding this will help us do a better job selecting the most efficient light source in terms of either eliciting a circadian response during the day or preventing it at night. As we continue the migration toward LED technology, we will have more refined ways to optimize the quality and amount of light both during the day and at night. For example, we can now spectrally tune LEDs to insert or remove blue content and can specify warm dimming as an option.”

Distributors interested in circadian lighting should get educated about the latest research and principles, and identify experts and manufacturers that can be used as a resource. Distributors may also benefit from being able to point out poor approaches, such as a space that operates during the day and night but maintains blue-rich, high-intensity light at night instead of adjusting to warmer, lower-intensity light.

“Like any new field, it will likely take a decade or more to become mainstream, but that creates a great opportunity for you to lead your organization into this emerging field,” Roos says. “An opportunity to create your network of experts that allow you to step into a non-commoditized ‘blue ocean’ field and differentiate yourself in your served markets.”

Hollander concludes: “The convergence of growing research on the connection between lighting and health and the capabilities of solid-state lighting and controls presents an exciting opportunity. We can dramatically change our approaches to lighting spaces and deliver a new level of interaction between occupants and their space.”