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Masters of Light: Mark Sutton-Vane on Invisible Light

In “Invisible Light,” Mark Sutton-Vane of Sutton Vane Associates explores how to use concealed lighting hardware to articulate and re-interpret building architecture.

Episodes of the UK’s LIGHTING Magazine’s “Masters of Light” webcast series are now available for on-demand viewing. In this series, lighting designers, artists and architects talk about their work, methods and philosophy in one-hour retrospectives hosted by the magazine’s editors.

In “Invisible Light,” Mark Sutton-Vane, Sutton Vane Associates explores how to use concealed lighting hardware to articulate and re-interpret building architecture.

Click here to check it out. Registration required.

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New GATEWAY Report on Tunable Lighting in a Behavioral Health Unit

DOE has released a new report on a tunable lighting system installed at the Swedish Medical Behavior Unit in Seattle that sought to leverage biophilic design principles.

The U.S. Department of Energy’s GATEWAY program has released a new report on a tunable lighting system installed in the new Swedish Medical Behavioral Health Unit in Seattle that sought to leverage biophilic design tenets. The unit incorporates color-tunable luminaires in common areas, and the lighting system uses advanced controls for dimming and color tuning, with the goal of providing a better environment for staff and patients.

The report reviews the design of the tunable lighting system, summarizes two sets of measurements, and discusses the circadian, energy, and commissioning implications as well as lessons learned from the project, which provided a chance to better understand how LED systems are delivering value to end users, and how those systems can be improved to deliver better quality and efficiency.

Among the key takeaways:

• Tunable LED systems can provide significant energy savings compared to non-tunable alternatives, based on the dimming typically incorporated into tunable applications.
• Achieving design goals related to circadian and other biological and behavioral effects of lighting sometimes requires higher illuminances than those recommended for visual tasks, and consequently may increase energy use during the hours when those high illuminances are needed.
• Allowing the building occupant some degree of manual control can increase energy savings.
• Commissioning of tunable systems remains a challenge.

Scientific evidence continues to emerge, relating the medical effects of tunable lighting to proposed lighting metrics, but none of the metrics have been formally adopted for use in lighting practice.

Click here to get the report.

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Outdoor Lighting 101

Outdoor stationary lighting presents a substantial market and a distinctive subset of lighting design. This article, which I wrote for the November issue of tED Magazine, describes considerations for evaluating and designing outdoor lighting systems.

Below is another article I wrote for the November issue of tED Magazine. Reprinted with permission.

Outdoor stationary lighting presents a substantial market and a distinctive subset of lighting design. While the market covers a variety of applications, the largest are building exterior and area and roadway lighting.

In a typical indoor space lighted during the day, the ceiling is relatively bright, the light is localized and has little or no impact on the natural environment, and the eye uses photopic vision. With outdoor lighting, the “ceiling” is relatively dark, unshielded lighting may be visible at great distances and impact the environment, and the eye may use scotopic vision (dark conditions) or mesopic vision (semi-dark).

Generally, the primary goals are to enable nighttime business, leisure, and enjoyment while promoting safety and security. A key decision is choosing what to light. Good outdoor lighting lights only what is needed without glare, light trespassing onto neighboring properties or negatively impacting wildlife, and uplight that can produce skyglow.

In this article, we will discuss outdoor lighting design considerations and the basic design process. It is based on the Illuminating Engineering Society’s (IES) RP-33-14, Lighting for Exterior Environments and other sources.

Visual factors
Visual factors relevant to outdoor lighting include light level, brightness, visual adaptation, and color quality.

Light level.
Measured in footcandles or lux (metric), light level is the quantity of illumination falling on a specific area. The designer’s aim is to ensure sufficient light output to provide an average or minimum light level over time, which may be defined by the maintenance interval. IES recommends a range of light levels for accent, building entry, facade, fountain, parking deck, parking lot, pedestrian stairs, roadways, outdoor pools and retailing, pedestrian path, and other applications. A second goal is to provide a uniform distribution of light. IES recommends maximum-to-minimum and average-to-minimum light level uniformity ratios.

Brightness. Luminance is the light reflected or emitted to the observer’s eye; brightness is the subjective perception of luminance. Excessive brightness is glare, which may be disabling or discomforting to vision. A bright outdoor luminaire does not equate to sufficient light level.

Visual adaptation.
The eye takes time to adjust from light to dark, including reduced visibility. Good outdoor lighting provides smooth transitions from bright to dark areas. In a large visual environment, very bright areas may result in less visibility in adjacent dim areas within view.

Color quality. At very low light levels, the eye adapts to scotopic vision, which is essentially colorblind, with an exception for very bright objects such as traffic lights. Most urban environments deliver enough ambient light to enable mesopic vision, a combination of photopic (daytime) and scotopic (nighttime) vision. For greater visibility, consider luminaires with some short wavelength (blue) output. Short-wavelength light is more likely to be judged as glaring, however, because the eye is more sensitive to this radiation at low ambient light levels, and short-wavelength light scatters more widely than other wavelengths within the eye. Outdoor luminaires should be selected with an appropriate spectral mix that provides both visibility and visual comfort.

Image courtesy of Wattstopper.

External factors
A variety of external factors influence selection of outdoor lighting, from space use to community master plans to local regulations regarding wildlife. Here, we will focus on three: energy codes, dark-sky ordinances, and American Medical Association (AMA) guidelines.

The latest generation of energy codes and standards prescribe maximum allowable power for outdoor lighting by application. These power densities are declining as more-efficient LED outdoor lighting has become viable. Codes and standards also contain detailed mandatory control requirements.

Dusk-to-dawn lighting must be turned ON/OFF using a photocell. During operation, power must automatically reduce by at least 30 percent after business operations or in response to occupancy. Façade/Landscape lighting must be operated using a combination photocell/time switch that turns it OFF between midnight or business closing (whichever is later) and 6:00AM or business opening (whichever is earlier).

Dark-sky ordinances vary but are generally designed to limit light trespass, skyglow, or both. Light trespass occurs when light spills onto neighboring properties. Skyglow occurs when uplight from nighttime lighting obscures a view of the stars. Many communities have adopted the Model Lighting Ordinance (MLO) developed by the IES and International Dark-Sky Association, which addresses both light trespass and skyglow in addition to energy efficiency and glare.

Both the major energy code standards and the MLO base requirements on a lighting zone (LZ) system (LZ 0-4). These zones range from no ambient light (e.g., wilderness parks and preserves) to high ambient light (e.g., high-activity commercial districts).

In 2016, the AMA issued community guidance cautioning against glare, which can affect safety, and LED lighting with a very cool correlated color temperature (CCT), which may suppress melatonin production. AMA specifically recommended 3000K sources, luminaire design that minimizes glare and light trespass, and dimming during off-peak operation. While cooler CCT sources remain more efficacious (lumens/W) than warmer CCT sources, the efficacy gap has been shrinking, increasing demand for warmer sources. The CCT recommendation received considerable pushback from the lighting industry, including IES, which issued a public statement saying the 3000K recommendation is insufficiently substantiated and that CCT itself is not an appropriate metric for predicting health outcomes.

Product selection factors
A wide variety of factors influence outdoor luminaire selection. Wattage, light output and distribution, glare control, color quality, ruggedness, certifications, aesthetics, maintenance, cost, and others come into play. Due to energy codes, controllability of LED sources, and advances in wireless connectivity, lighting controls are becoming much more important, offering extraordinary possibilities for global management and data collection.

The Backlight Uplight Glare (BUG) luminaire classification system developed by IES in TM-15-11 offers a useful tool for evaluating luminaire quality. Featured in the MLO. BUG delineates a luminaire’s light output by zones and tags these zones by distribution—backlight, which can cause light trespass; uplight, which contributes to skyglow; and glare, which is objectionable light. There are three zonal regions for backlight, for example (high, middle, and low). The MLO establishes maximum zonal lumens for each by LZ. Many luminaire manufacturers publish BUG ratings for their outdoor luminaires, while the MLO provides maximums by LZ.

Putting it together
All of the above must be matched to the application to provide the optimal customer solution. With the proliferation of the LED source, outdoor luminaires now offer much more expansive and robust capabilities, such as superior optical control, dimming, collecting data, and changing color by time of night. By understanding the basics of outdoor lighting, electrical distributors can add even greater value to projects.

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IES 2018 Illumination Awards Opens January 2

Submissions open January 2, 2018 for the IES Illumination Awards program, which recognizes individuals for professionalism, ingenuity and originality in lighting design.

The IES Illumination Awards program recognizes individuals for professionalism, ingenuity and originality in lighting design. Submitted projects are judged on how well the lighting design meets the program criteria. 2018 marks the 45th anniversary of the IES lighting awards program.

Submissions open January 2, 2018. Submit before Feb 2 for reduced submission rates.

Click here to learn more.

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Product Monday: Architectural LED Luminaires by Apure

Designed to enable higher ceilings and architectural flexibility, Apure’s MINUS product series offers an ultra-thin profile for minimal recess and an almost imperceptible aperture. The MINUS, designed by Porsche Design…

Designed to enable higher ceilings and architectural flexibility, Apure’s MINUS product series offers an ultra-thin profile for minimal recess and an almost imperceptible aperture.

The MINUS, designed by Porsche Design Studio, features proprietary precision optics engineered to distribute light very evenly without glare. The luminaire itself is invisible to the eye and is available in two form factors; MINUS ONE, a round finish, and MINUS TWO, a square finish.

Recesses 3/4 inch, choice of 2700K, 3000K, or 4000K CCT with 80 or 90 CRI, fully dimmable (flicker free down to 1%), 50,000 hours, 20° or 40° beam angle options, source output 1,140 lumens, five luminaires per 100W transformer.

Click here to learn more.

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Rethinking Exposure to Saturated Colored Light

In the most recent issue of Architectural Lighting, LRC Director Dr. Mariana Figueiro explains how red and blue light can be a means of increasing daytime alertness and nighttime sleep….

In the most recent issue of Architectural Lighting, LRC Director Dr. Mariana Figueiro explains how red and blue light can be a means of increasing daytime alertness and nighttime sleep.

While tunable lighting systems provide a dynamic lighting solution that create an aesthetically pleasing environment for users, when it comes to circadian-effective lighting, layers of saturated colored lights delivered at the plane of the cornea, rather than white light coming from the ceiling, may provide a more energy-efficient, comfortable, cost-effective, and aesthetically pleasing design solution.

Check it out here.

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IES Issues Call for Posters for 2018 Research Symposium

The Illuminating Engineering Society has issued a call for posters for the 2018 IES Research Symposium, which will explore how light affects human health. The deadline for abstract submissions is December 15, 2017.

The Illuminating Engineering Society has issued a call for posters for the 2018 IES Research Symposium, which will explore how light affects human health.

The deadline for abstract submissions is December 15, 2017.

The symposium will be held at the Crowne Plaza Atlanta Midtown in Atlanta, April 8-10, 2018.

Click here to learn more.

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Evaluating Color with LED

LEDs have further differentiated themselves from traditional light sources by offering dramatically expanded color capabilities. These capabilities enable distributors to better serve existing customers and build new markets. Accomplishing this requires understanding LED technology, metrics used to evaluate color, and knowing what the customer wants and needs.

Below is my contribution to the November issue of tED Magazine. Reprinted with permission.

LEDs have further differentiated themselves from traditional light sources by offering dramatically expanded color capabilities. These capabilities enable distributors to better serve existing customers and build new markets. Accomplishing this requires understanding LED technology, metrics used to evaluate color, and knowing what the customer wants and needs.

The LED advantage
Visible light is energy residing along the 400-700 nanometer band of the electromagnetic spectrum. The size of these wavelengths corresponds to specific colors from violet to red. Combining these wavelengths produces white light. Separating them via a prism produces a rainbow.

The eye perceives color in an object because that color is present in both the object and the light striking it. The object absorbs all colors except a given color, which reflects to the eye. While daylight offers a full spectrum source, electric light sources are engineered as mixes of wavelengths at relative intensities, typically focused on red, green, and blue (RGB). The spectral makeup is expressed in the source’s spectral power distribution (SPD).

As with traditional light sources, with LEDs we have a choice of specific colors or white light. In the case of color, this is accomplished with LEDs emitting light in a narrow spectral band. For white light, blue or ultraviolet LEDs coated with a phosphor producing a deep blue peak and high irradiance in the 470-630 nanometer range.

With LEDs, however, colors can be mixed to produce virtually any color needed, allowing dynamic effects. White light color appearance can be adjusted with relative ease using controls. Combining white and color LEDs allows virtually any SPD to be created, opening possibilities in targeting light to human physiology, plant growth, and environmental needs. And with advances in LED technology, building owners no longer have to choose between excellent color quality and high efficiency.

Tunable-white LED lighting, matched with appropriate controls, enable CCT adjustment across a given range to satisfy variable preferences for applications demanding color flexibility. Image courtesy of USAI Lighting.

Color appearance

Manufacturers describe the color quality of light sources using metrics based on standardized measurements. The most popular are correlated color temperature (CCT) and color rendering index (CRI).

Measured in kelvins, CCT is the color appearance of a light source relative to an ideal reference light source. Color appearance is generally classified as visually warm (about <3000K, or yellowish white), neutral (about 3500K, white), or cool (about >4000K, or bluish white). A light source heavily laden in blue and deficient in red wavelengths will saturate blues in the space while muting reds.

A challenge for LEDs is the manufacturing process inherently involves variations in CCT. The result is potential color variation between LED products. To address this issue, manufacturers test and bin their LEDs according to deviation from CCTs based on x, y coordinates on the CIE 1931 Chromaticity Diagram, using a standardized method. The smaller the bin, the tighter the control of color variation, though gaining this consistency may impose a higher cost. Some manufacturers maintain extremely tight deviation as a point of differentiation for their products.

“Color consistency from credible LED manufacturers has improved significantly since white LEDs were first produced,” said Andrew Kites, Global Product Manager, Philips Lighting. “Some manufacturers have gotten much more skilled at producing LEDs that are closer to the center of the ANSI bin for that CCT, reducing waste in manufacturing from out-of-spec product, reducing LED costs, all while improving color consistency.”

Advances in control and driver technology enable manufacturers to provide custom SPD (using RGB+ LEDs), luminaires to produce both high-quality white and color (White+), and designers and users to adjust CCT in the field (White/White+). This extraordinary potential is opening new markets. Additionally, dim-to-warm LED products are growing in popularity for applications where users expect their lighting to dim to a warm glow similar to incandescent.

“It’s always important to listen to the customer,” said Bonnie Littman, President and CEO, USAI Lighting. “The better we can understand their preferences for color, the better we can serve them and provide the right product. There’s no ‘one size fits all’ when it comes to lighting, and there’s no reason someone should be relegated to static white light if that’s not what they want or need.”

She pointed to several examples where coming up with a customer-specific color solution became a point of differentiation for her company. Outdoor lighting on the Gulf Coast that provided nighttime visibility without disrupting the nocturnal habits of sea turtles. Experimentation with different CCTs in classrooms. Optimal SPDs for high-end retail. As the industry’s understanding of light and health develops, this capability may prove integral to circadian lighting, as spectrum is a major factor in circadian response. And some manufacturers are already looking beyond health to well-being, mood, and satisfaction via personalized lighting solutions.

“Research is ongoing to determine the appropriate light levels, spectral content, and lighting design that provides support for human circadian biorhythms,” Kites said. “The research points to humans generally having a biological response to both blue and red wavelengths.”

“With all of the promising LED products on the market now to support circadian health, I see this time as an exciting moment for the lighting industry to have a meaningful impact on workplace and healthcare environments,” Littman noted. “By mimicking the daily color temperature cycle of natural daylight, these technologies we’re creating can help minimize disruptions to the natural circadian rhythm, thus supporting overall health, well-being, and healing.”

Paul Scheidt, Product Marketing Manager, LED Components, Cree, however, says he has not yet seen a product that demonstrates a comprehensive understanding of physiological response to lighting. “The industry is not here yet,” he said. “We have identified the right variables for circadian lighting—color and light amount. However, we do not know where or how you set these controls to create direct biological impact, such as mood and energy levels. No one has a ‘mood’ knob on their light. Today’s controls are color and light amount. As an industry, we are still at the beginning of understanding the notion of mood and human preference for lighting.”

Color rendering and TM-30
While CCT is useful, it does not indicate whether the light source renders colors how most people would expect them to appear. Two sources with the same CCT may render various colors differently due to differing SPDs. A balanced SPD, particularly RGB, generally means the source offers good color rendering. A simpler and more direct way to evaluate color rendering is the lamps CRI rating. If two sources have the same CCT, one can meaningfully compare CRI to choose the right source.

Manufacturers test their sources and calculate CRI based on how closely they render eight standard color samples compared to an ideal reference source with the same CCT. The CRI rating is the average of these values. The less deviation from the reference source, the higher the CRI. Traditionally, about 80+ CRI is considered “good” for typical commercial applications requiring social interaction, about 90+ for color-critical applications such as higher-end retail. While the standard has endured, it has not been updated in many years, and its limitations are more pronounced with LED technology. In particular, a source may have a high CRI while ineffectively rendering saturated reds commonly found in applications like retail, supermarkets, etc. For this reason, some manufacturers began publishing R9 values to indicate color rendering for saturated reds for sources serving these markets.

The core problem of CRI’s deficiencies remained, however, particularly in light of CRI being used in specifications such ENERGY STAR and the DesignLights Consortium, and in regulations such as California Title 20 and Title 24. In 2015, the Illuminating Engineering Society (IES) published TM-30, a method for evaluating color rendition that introduces two new metrics. First is the Fidelity Index (Rf). Based on 99 color samples instead of 8-14, it was designed as a more accurate alternative to CRI. Second is Gamut Index (Rg), which expresses average color saturation. To determine which colors are saturated or muted, graphics are provided. While more comprehensive and precise than CRI, adoption has been slow.

“Right now, the whole industry is still in the process of educating lighting designers,” said Scheidt. “For the most part, the lighting designers who have heard of TM-30 and understand it really like it and see the benefits of getting more information about the light ahead of time, without having to do trials.”

He added that TM-30 is useful for applications where color is important, such as museums, hospitals, car dealerships, retail, and some offices.

Selling with color
Traditionally, the key to selling with color is to know the customer and the application, understand best practices, and recommend lighting products that will satisfy the need for an appropriate cost. LED is no different, though it can accommodate a broader range of needs, thereby creating new markets. It provides a more powerful tool to explore and understand lighting’s impact on people than traditional sources ever could.

Scheidt said the first step is to do no harm. “It’s fairly simple,” he said. “If the color is bad, then people are not going to like the product and you will have more returns and unhappy customers.”

After that, he pointed out, listen to the customer to find out what they need. “Distributors do not always need to recommend the best color performance or the best color consistency into everything,” he added. “It’s about understanding which customers are going to care about color and which ones aren’t.”

“The only consideration you should need to make is the customer’s preference,” advised Littman.

To produce the right solutions, distributors further need to understand LED technology and the metrics used to evaluate products. “Customers new to LED lighting will look for recommendations, and distributors have the opportunity to help educate the market,” Kites said. “Spectral knowledge and color-tunable systems are new and exciting to the lighting industry, and will bring more challenges and opportunities to the market. The more we know and understand how these systems can positively impact our customers, the bigger the opportunity to bring value to our customers.”

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TLED Lamp Adoption Continues to Grow

The NEMA Linear Fluorescent Lamp Index showed respective market share of 57.3% for T8, 8.6% for T5 and 12.4% for T12 in the first quarter of 2017. Remarkably, TLED lamps, which accounted for 15.3% of shipments in the first quarter, increased to 21.7% in the second quarter.

The NEMA Linear Fluorescent Lamp Index showed respective market share of 57.3% for T8, 8.6% for T5 and 12.4% for T12 in the first quarter of 2017. The index rating for each of these declined by 10.5%, 9.3% and 8.1%, respectively, compared to the first quarter.

Remarkably, TLED lamps, which accounted for 15.3% of shipments in the first quarter, increased to 21.7% in the second quarter.

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Product Monday: Healthcare Light by Focal Point

A collaboration with Curbell Medical Products, Focal Point’s Apollo 8 LED is an 8” x 4’ linear recessed LED luminaire available in three configurations to support common considerations for healthcare design: comfort, function, safety, sustainability, and health and wellness.

A collaboration with Curbell Medical Products, Focal Point’s Apollo 8 LED is an 8” x 4’ linear recessed LED luminaire available in three configurations to support common considerations for healthcare design: comfort, function, safety, sustainability, and health and wellness.

Its clean form with soft curves imparts visual appeal, while its durable construction meets clinical requirements. A smooth acrylic diffuser with internal ribs provides even illumination and easy wipe down. The secure lens, silicone gasket, and antimicrobial finish ensure protection from contamination and inhibit microorganism growth. Utilizing an asymmetric focusing optic, the exam function delivers shadow-free, uniform illumination onto patient beds. Meanwhile, the reading light is strategically angled for optimal surface plane illuminance and patient comfort.

Apollo 8 LED provides flexibility with various color temperatures (3000K – 5000K), standard options of 80 and 90 CRI, and efficiencies greater than 100 LPW for all configurations. As part of the Right Light™ program from Focal Point, Apollo 8 LED contains tunable drivers to allow for custom wattage and lumen outputs to be specified within the standard range.

Click here to learn more.

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