SPOTLIGHT REPORT Lighting Design for Health and Sustainability: a Guide for Architects Editors

SPOTLIGHT REPORT Lighting Design for Health and Sustainability: A Guide for Architects Editors

Paula Melton Editorial Director Brent Ehrlich Nadav Malin Alex Wilson James Wilson Peter Yost

Graphic Design Julia Eva Bacon

Cover Photo

The Louisville Free Public Library South Central Regional Library Photo: Brandon Stengel

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Published by BuildingGreen, Inc. 122 Birge St., Suite 30 Brattleboro, Vermont 05301 ©2021 BuildingGreen, Inc. All rights reserved. BuildingGreen Spotlight Report Lighting Design for Health and Sustainability: A Guide for Architects Lighting is an essential element in quality environments that support health and wellness while reducing energy use. By James Wilson Associate Editor

The functionality of a building is largely dependent on the quality of its lighting. In order to safely and comfortably perform their tasks, occupants need lighting that provides adequate visibility without causing discomfort or distraction.

But a focus on quality is also the key to achieving sustainable lighting.

As Nancy Clanton, CEO of Clanton & Asso- ciates, advises, “Don’t design for energy savings; design well, and the result will be incredible energy savings.” By creating quality lighting conditions in their Photo: Lara Swimmer buildings, not only will project teams The third-floor reading space of the Madison Central Public provide functional and comfortable lighting conditions and improved produc- Library, designed by MSR, is spaces, but they’ll also achieve efficiency. tivity as well as higher student test scores. designed to receive an Studies also suggest that quality lighting abundance of daylight. And because the lighting in a space has has positive impacts in healthcare set- such a significant impact on how- peo tings—for example by improving the ple use that space and how they feel mood and perception of both staff and while in that space, it is critical to the patients. Conversely, poor lighting con- human-health component of sustain- ditions can hinder the way people work, ability. Lighting affects not only the per- learn, and heal by causing distraction, formance and productivity of occupants discomfort, and fatigue. but also, more critically, their well-being. High-quality lighting, beyond providing Getting the light right is crucial. As Bob basic comfort, can protect and promote Harris, FAIA, principal at Lake|Flato Ar- health. chitects put it, “If you’re not doing a good job with lighting, you’re not going to be doing a good job architecturally.” He ex- The effects of lighting plains that lighting is often treated as a Like acoustic design, lighting design can secondary concern, taking a back seat to have either positive or negative effects form-making. Too often, he argues, archi- on people, especially in the spaces where tecture is conceived of as an object to be many people spend a lot of time, like viewed from a detached position rather schools and offices. Research has shown than as a habitat to be experienced and positive correlations between quality lived in.

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And of course, in addition to affecting And some LEDs also contain copper, usability, comfort, and health, the way a which can create an environmental building is lit also affects its environmen- hazard if it accumulates in waterways. tal impact. (LEDs, despite their long life, will eventually need to be replaced. They can be disposed of in regular landfills, What do we mean when we as they are not currently regulated as say sustainable lighting? hazardous waste.) A wide variety of sustainability issues intersect with architectural lighting. Though this report will largely focus on energy efficiency and occupant health and wellness, it is important to also consider the following related concerns when developing an integrated approach to sustainable lighting:

• Light pollution—Project teams should avoid over-lighting, prevent light trespass, and consider potential impacts of lighting on the plant and animal life of the surrounding ecosystem, as well as on neighboring buildings, places, Photo: Mike Knell. and communities. License: CC BY-SA 2.0. High quality, low energy As part of an integrated • Life-cycle impacts of lighting prod- approach to sustainable ucts—Lighting designers should work The information offered in this report lighting design, project with manufacturers over time to re- generally revolves around lighting design teams should avoid lighting strategies that contribute duce the embodied energy and car- that provides building occupants with the to light pollution. bon cost of fixtures, luminaires, and highest-quality illumination possible— lamps. To help extend the life of the providing comfortable and safe environ- building and further reduce environments in which to complete their tasks— mental impacts, when appropriate the while using as little energy as possible. lighting should be designed so that it can be easily retrofitted and adapted According to the Energy Information Ad- to align with future technology administration, in 2012, lighting in U.S. com- vances. (See Modular LED Lighting mercial buildings required 212 billion Enters the Mainstream and Product as kWh of electricity—about 17% of total a Service: Buying the Lumen, Not the commercial building electricity used in Lightbulb.) the nation. But technology has been rapidly evolving, and it’s becoming ever eas- • Chemicals of concern—Project teams ier and more cost effective to drastically should advocate and work with man- reduce the amount of energy consumed ufacturers to, over time, reduce the by lighting. In fact, LEDs have become level of toxic materials in lighting so efficacious that additional gains in products. For example, compact flu- efficiency are small. The point has been orescent lights, which contain highly reached where many in the lighting in- toxic mercury, have to a large extent dustry, who now see energy efficiency as been replaced by LEDs, which do not a given, are turning most of their atten- contain mercury. However, some- tion to the human-health component of times LEDs are manufactured with sustainability and the ways that quality high levels of lead and heavy metals. lighting can support it.

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Designing Sustainable Lighting LEARN THE LINGO: Lighting Literacy In pursuit of quality sustainable lighting, One option is to have the lighting design- a good place for any project team to start er give a brief educational presentation to • Color Rendering Index (CRI): a metric that describes is with a refresher on the fundamentals the entire team. This would also allow the how faithfully a light source of how light and human vision work. A lighting designer to catch everyone up on renders the true colors of ob- good grasp of the relationship between the latest information about lighting tech- jects and spaces (natural light light levels and what people actually see niques and technologies. (For example, a has a perfect index of 100) can go a long way toward helping the basic understanding of how LEDs work • Correlated Color temperature (CCT): often shortened team make design decisions that will con- and how to evaluate the quality of differ- to “color temperature” or tribute to efficiency, health, and comfort. ent products can be very useful. See our “Kelvin temperature,” it is previous feature article, LEDs: The Future used to described the color Understanding the difference and rela- Is Here.) The lighting industry is a rapidly output of a light source— Common CCT values include: tionship between “measured light”—for evolving and increasingly complex field, » warm, slightly example, the amount of lumens that a fix- and knowledge that was current only a 2,700K: ture emits—and “perceived light”—what yellow tone, used to create few years ago may already be outdated. relaxing environments a person actually sees—shifts the focus » toward designing for effects of light and Brennan Schumacher, lighting design- 4,000K: neutral white tone, used to create “balanced” away from engineering for light levels. er and associate principal at Mazzetti + environments that allow GBA, told BuildingGreen that on every for both relaxation and project he works on, he gives a presen- concentration 1. Learn the basics of light tation to the entire project team early in » 6,500K: cool, slightly As the members of a project team may all the process. This allows him to educate blue tone, used to create environments that have an have different levels of knowledge and them about his design perspective and energizing effect experience with lighting, it can be useful approach to sustainable lighting design. • Glare: a vision impairment and efficient to devote some time, at the “I think that adds a lot of value for the caused by either direct or beginning of the design process, to getting owner and the architects,” he said. “I get reflected intense light; occurs everyone up to speed and on the same a lot of comments from the civil engineer, whenever there is a high contrast between a light source page. the landscape architect, or the mechani- and the surface or object being viewed • Luminous flux: the total output of light emitted by a light source, measured in lumens • Reflectance: a property of surfaces, expressed as the ratio of reflected light to incident light • TM-30-15: often shortened to TM-30, a method of evaluat- ing and communicating the color rendering properties of a light source that includes several related measures and graphics, and which improves on the CRI method • Wall grazing: a lighting effect where a wall with an irregular, granular surface is illuminated creating both highlighted and shaded areas • Wall washing: a lighting effect where a wall is illuminated so that surface irregular- Image: J.C. Walker. License: CC BY-SA 3.0. ities are minimized, making It is useful for architects to know the definitions of different lighting metrics and how they relate. the surface appear smoother

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cal engineer about things that they have back of the eyes. The rods and cones INSIGHT not thought about in regard to lighting.” respond by sending a signal through the optic nerve to the brain, which Brendon Levitt, senior asso- Examples of some basic information that then communicates what is seen. ciate at Loisos + Ubbelohde, might be covered in such a presentation Vision is not about the amount of light described the importance of include the following. understanding the concep- a person sees but about what that tual relationship between person perceives in the surrounding the task being performed in What light is, and how it interacts environment. a space, the material in that with building surfaces space, and how that space is • Humans have, at the backs of their illuminated: • Light consists of photons, invisible eyes, photosensitive retinal gangli- “I think that’s either misunder- particles that are only perceived via on cells that send different signals stood or not well understood their interaction with matter. This is to the brain based on the light they in a lot of cases. Understanding the room as light fixture is a what’s called light propagation—the are exposed to, impacting hormone critical piece. reflection of light off of surfaces. What production. This means that light af- people see as light is the reflected col- fects a person’s physical, mental, and "We were in a project where or of surfaces. behavioral states. For example, when we’d been going through this with the architect and talking exposed to bright blue or white day- • Light reflects differently based on the about these corridors and how light, the body suppresses the produc- the lighting would work with it, color and structure of the surface at tion of melatonin, making a person and we had a strategy where the microscopic scale. Smoother sur- we were going to illuminate alert and awake. When exposed to faces—like glazed tile—produce more the ceiling with an uplight in the warm red and yellow tones of the direct reflections of light and are de- order to get a nice diffuse light setting sun, the body increases pro- throughout the corridors. scribed as “specular.” Incident light— duction of melatonin, which makes the light that falls on a surface—is re- "Then the interior designer a person relaxed and induces sleep. flected back at close to the same angle came on and decided that they This light-and-dark cycle is known as wanted to have a really dark at which it strikes the surface. Matte circadian rhythm. walnut ceiling. And basically surfaces—like unfinished wood or they completely absorbed all stone—are rougher and produce dif- the light we were throwing up fuse reflections of light because the The factors that affect visibility, onto the ceiling and negated all the work that we did. So we had incident light that hits it is scattered, which has little to do with light to redo the whole design based meaning the light reflects off different levels on that decision. portions of the material at different • the luminance, or reflected light, "I don’t think the interior angles. The darker the color of the sur- in the space that our eyes perceive architect had any idea that that face, the more light is absorbed and would affect the lighting. So it’s the less is reflected. • the contrast between different a combination of understanding what surfaces are being luminance values in a space illuminated and what materials How humans perceive and are those are because in effect, by • the size of the objects in a task being illuminating those materials, affected by light performed you’re creating another light • Humans have evolved over a long pe- fixture." riod to see the way they do, relying, for • the duration of time spent most of their existence, on the sun as performing the task their primary source of light. (Fire was discovered in the Stone Age and then The definitions of different light- combined with reflectors around 200 ing metrics and how they relate CE for use as a light source. Electric • Luminous flux, measured in lumens, lighting only started to become com- refers to the light output of a fixture. mon in the early twentieth century.) • Illuminance, measured in lux or • The lenses, pupils, and irises of human foot-candles, refers to the amount of eyes control how much light is trans- light that falls on a surface. mitted to the rods and cones at the

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• Luminance, measured in candelas specifying fixtures, the lighting designer’s INSIGHT per square meter (cd/m2), refers to the role has evolved over the past decade or amount of light reflected off of surfac- so as architectural practice shifts toward Brendon Levitt, senior associ- es that our eyes perceive. (The candela more integrated approaches. Architects ate at Loisos + Ubbelohde, de- is the base unit of luminous intensity, now often collaborate closely with light- scribed the iterative process involved in lighting design: which is the power emitted by a light ing designers, starting in early phases of source in a particular direction.) design, when massing decisions, which “You have to go through a few significantly affect opportunities for day- times. Very rarely is it possible to get it right on the first try. The Brendon Levitt, senior associate at Loisos light, are being made. And, increasingly, + Ubbelohde, explained why it’s import- reason for that is that there are a project teams are looking for ways to in- lot of variables here, and it’s not ant to understand these basic concepts tegrate lighting considerations from the a determinative solution. You and the general relationship between very beginning of the design process, can’t say, ‘I need 62 foot-candles light sources and architecture. “It really on these three surfaces and so rather than treating it as a kind of orna- the only solution is this right translates as, ‘What particular surface are mentation that’s added on to a design. here.’ There’s about a million you illuminating, for what purpose?’” he different variables between the said. “I think if more architects could ask Great lighting design often appears seam- aesthetics, the architectural themselves that question, they’d get to the less, and some may misinterpret that as intent, the task, the occupants’ expectation, the budget, the bottom of the lighting design a lot faster. meaning the task was effortless. The re- controls, the technology that’s They’d sort of answer a lot of questions ality, however, is that achieving quality available, the code restrictions, for themselves about what they’re trying lighting often requires an extensive, it- what your local jurisdiction is, to accomplish. Because there always has erative process and involves balancing how much light egress you get, what impact you have on other to be a surface that’s illuminated.” a range of factors. The expertise of a habitats, it goes on and on and lighting designer can go a long way to- on. And so all these different ward making that process valuable and things mean that you’re going through this multiple times and 2. Work with a lighting effective. But in order for this to happen, you’re looking at it from multiple design consultant it’s important to treat lighting designers perspectives each time.” Including a lighting design consultant on as collaborators rather than just having a project team is a great way to ensure them run calculations or specify fixtures. that lighting concerns are integrated into A skilled lighting designer will be able to the design. help blend together all the various, inter- dependent elements that affect the quali- Although in the past architects relied ty of lighting. on lighting designers mainly for help

Photos: Timothy Brown (L), Andreas Praefcke (R) . License: CC BY 2.0. Louis Kahn, architect of the Kimbell Art Museum, worked with lighting designer Richard Kelly to develop the curved reflectors of the museum’s skylight system. The reflectors spread indirect natural light across the gallery ceilings while preventing direct sunlight, which would damage the paintings, from entering the space. Commissioned in 1966, the project used a computer expert to help determine the precise shape of the reflector’s curve—one of the earliest instances of designers using computer technology to model architectural components.

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For example, Susan Morgan, AIA, for- merly an architect at MSR, explained that the firm seeks to collaborate with lighting designers who have a facility with both the quantitative and the qual- itative performance aspects of lighting because it allows for early conversations about how to achieve quality of place. “It really becomes a dialogue about where are the opportunities for lighting to help reinforce whatever it is,” she said. “If it’s in a large reading room in a library, it’s about being welcoming and comforting; if it’s about the design of an entry space, we want to present a strong sense of character and identity.”

Image: Lake|Flato Architects 3. Start early Having a lighting design consultant in- A section diagram explaining the volved from the early stages of design daylighting strategy used at the As is true with most aspects of high-per- Indian Springs School, designed can also help the project team ensure that formance design, it is crucial to start con- by Lake|Flato Architects. they are pursuing cost-effective solutions. sidering lighting early in the process. The An experienced lighting designer can help best way to maximize the value offered by a project team assess factors like installa- a lighting design consultant is to involve tion, programming, and maintenance to them from the beginning of the project. determine if a given lighting technology Clanton explained that, in terms of work- or strategy will be financially sustainable. flow, it is ideal for the lighting designer to be involved early to talk with the archi- 4. Communicate effectively: tect about their ideas for materials, colors, and different scenes. She described this a way to talk about what process as a kind of walkthrough of the light can do building with the architect to understand When collaborating, it can be helpful for the vision for how the spaces should be a lighting designer and an architect to experienced and to discuss how the light- have a common vocabulary to discuss ing can support it. how light can be used and to what effect. This contributes to a more informed di- Additionally, as energy codes continue to alogue about how the project’s lighting evolve and as the requirements relating design impacts energy performance and to lighting change, it can be helpful to occupant health and comfort, which in have a lighting designer involved early turn results in a more efficient and effec- to assess and explain how the code could tive design process. potentially impact design decisions. In locations with more progressive energy Richard Kelly—who is generally recog- codes, there may be more stringent rules nized as the first modern lighting design- that restrict the number of design solu- er—came up with a set of categories of tions available. It’s important that the lighting effects in an effort to help the ar- project team integrate these parameters chitects he worked with understand light- into the discussion before spending too ing design. Many contemporary lighting much time and money developing a de- designers have adopted these terms, or sign that will end up not being compliant. variations of them, and find them to be

Lighting Design for Health and Sustainability 8 BuildingGreen Spotlight Report effective when thinking together with 5. Start with the sun INSIGHT project teams about light: The common view among lighting de- Brennan Schumacher, light- signers concerned with meeting sus- • Play of brilliance—refers to lighting ing designer and associate that sparkles, shimmers, or shines. tainability goals of efficiency, health, principal at Mazzetti + GBA An example would be a chandelier or and comfort, is that daylight is where described a successful project sunlight reflecting on water. all lighting design should start. After all, he worked on that demon- strates the value of a design daylight is free, abundant, and has pos- approach that integrates • Ambient luminescence—refers to itive effects on human well-being. For lighting early in the process: large washes of light, generally com- example, exposure to daylight boosts ing from the ceiling or walls. It’s what “We did the Indian Springs the body's production of vitamin D, a school with Lake|Flato. It’s a most people mean when they say “am- healthy supply of which is believed to little school outside Birmingham, bient light.” promote bone growth and prevent ill- Alabama—a series of classrooms nesses such as breast and colon cancers, and a couple offices. When they • Focal glow—refers to lighting meant started the design, it was small multiple sclerosis, and depression. for a specific task in a space. An exam- classrooms and windows on both sides of the classrooms. ple would be spotlights on an artwork And because designing for daylight has They were analyzing this. … This in a museum, or a task lamp on a desk implications for other major compo- is one where we were involved in an office. nents—structure, mechanical system, early on in the process, and we said, ‘What would you think if we landscape, materials, etc.—it is also the Lighting designers and architects use popped the top and put a roof most logical place to start when taking an monitor up there?’ these basic categories as layers that can integrative design approach. be overlapped and combined in differ- “They weren’t loving the idea ent ways to both adequately illuminate a “The first thing I want to know as the right away, but they were open space and produce visual interest, which to it. So we ran a series of calcs electric lighting designer is: where is the and renderings kind of showing is important for comfort. daylight coming from?” said Levitt. “I what this roof monitor could do. They loved it; they embraced it. They played with the form of that window a little bit, and we were analyzing the north and south side—really dialed it in. And now you can be in there and basically between the hours of 8:30 and 4 there’s not any direct sun that’s going to hit a student’s desk and yet the whole place is daylit. They would never need to have any electric lighting on during their hours of class. And I think that really is a singing success of integrated design and what it means to bring a lighting designer that’s willing to think about things in a more detailed or in a more sustainable way.”

Photo: Casey Dunn At the Indian Springs School, designed by Lake|Flato Architects, a roof monitor over classrooms fills the space with natural light and prevents glare. The result is a comfortable space that’s conducive to learning.

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think all electric light needs to start with daylight. Electric light should be for the evening, and during the daytime, whenever and wherever possible, the electric light should be off.”

Clanton told BuildingGreen that although some architects see her firm as dealing only with electric lighting, the first step in her practice is always to help design the daylighting. “If the daylighting is designed well, the electric lighting plays a very small role,” she said. “It’s not near- ly as great as what it would be in a space without daylighting.”

There are certain “rule of thumb” design strategies that can be applied to maximize the amount of usable daylight brought into a building, including:

• south- and north-facing orientations • narrow floor plates • high ceilings • open sections

Designing windows and rooms so that daylight is redirected to light the walls and the ceiling, and using lighter, more reflective materials on interior surfaces helps to distribute the daylight throughout the space. The darker the materials, the more light is absorbed, and the more electric lighting will potentially be needed to adequately illuminate the space. Image: Qais Tabib. comforting and beneficial connection to License: CC BY-SA 3.0. Project teams should also keep in mind nature. The more exposure people have Designers can use a number of that all electric lights produce heat—ei- to views and daylight, the better aligned different techniques to bring daylight into interior spaces. ther through radiation or convection— their circadian rhythms are to the natural and that this heat all eventually ends up dark-light cycle. And research suggests as heat in a space. So in addition to re- that maintaining a consistent circadian quiring more electricity, excess electric rhythm may help improve overall health light fixtures also raise energy use by in- and prevent chronic diseases. creasing the cooling load of a space. But it’s critical to control the amount of Design for daylight can also often pro- daylight entering a space, for example by vide occupants with views to the outside, adding shading devices to windows. Ex- which, because it relaxes the visual sys- tremely intense direct light and glare on tem, contributes to health and comfort. task surfaces can cause severe discomfort Where direct views to the outdoors are and make a space unusable. Over-glaz- not possible, reflecting dynamic, natural ing and failure to properly control the light into the space can also support a amount of daylight entering a build-

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ing can also lead to excessive solar heat tural design, and optimized for the space’s gain, causing thermal discomfort and in- particular use, electric light should be creasing the building’s cooling load. (See blended in to augment the natural light Rethinking the All-Glass Building.) and provide any additional illumination needed. Steps should be taken to mitigate potential glare, especially during early hours of In certain instances, it will not be pos- the day and in the evening, when the sun sible to get much daylight into a space. is low in the sky. If occupants draw their One example is the low floors of build- blinds to block glare, they often will leave ings in dense urban settings. In such cas- them drawn, reducing the energy and es, it does not make sense to spend time health benefits that would otherwise be and money to develop strategies based provided by incoming daylight. on daylight as a primary source. Basic early analysis tools can be used to study It’s also important to evaluate potential a project’s site and context and quickly daylight strategies in relation to all sky determine whether daylight will be a fea- conditions—clear, overcast, and partly sible option. cloudy—as any single design approach will perform differently under each. (For more information on designing for day- 7. Conduct early analysis light, see Doing Daylighting Right.) Project teams can use early analysis tools (like Sefaira, DIVA-for-Rhino, and Lady- 6. Integrate electric lighting bug Tools) to study the impact of the following characteristics, which will lead Once the available daylight has been fully to better, more informed lighting design considered, integrated into the architec- decisions:

Image: Sefaira Architects can use early analysis tools, like Sefaira, to study the impact of design decisions like orientation and window placement.

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• building orientation If an architect conducts early analysis INSIGHT • building form and footprint to study site conditions and massing op- tions, it can serve as a good starting point Susan T. Morgan, AIA, for- • placement and size of windows for discussions with the lighting design- merly an architect at MSR, • placement, shape, and size of exterior er about what’s possible regarding use described how the firm uses early analysis tools to solar shading of daylight and how electric light can be inform its understanding of integrated to augment it. The lighting de- • ceiling heights a project’s lighting potential signer can also, if involved early enough, and support its collaborations • section profiles help substantiate or improve the assump- with lighting designers: tions made for early energy assessments. Using early analysis tools to understand “It is now standard practice on our projects that we do a Sefaira which spaces receive daylight—and how daylight modeling study as we’re much daylight, and when—can inform 8. Focus on quality looking at preliminary massing programming, occupancy, and schedul- to help us understand orien- In terms of creating lighting conditions ing decisions. tation, building massing, and that are conducive to human health, well- geometry, and really maximizing ness, and comfort, the main objective is the floor plate for daylight within There are two common climate-based the building. It’s been about a metrics that early analysis tools generate providing for visibility, which has every- year-and-a-half since we put that to describe a building’s relationship with thing to do with the quality of light in an into practice, and for us it has daylight: environment and little to do with the ac- made a huge difference in us meeting our future and broader tual quantity of light provided. project goals from an energy • Spatial daylight autonomy (sDA) de- standpoint. scribes the percentage of a space that An environment that feels bright and bal- will receive sufficient daylight—de- anced, in which occupants can easily see “I think both on an individual and a team level, it’s increased fined as floor area that receives a min- what they need to see and where they are our literacy, and on the other imum illumination level for a mini- not distracted or fatigued by excess glare hand it’s given us both tools mum percentage of annual occupied or contrast, is the baseline requirement and vocabulary to educate our hours. For example, an area of floor for a quality lighting condition. Designers clients about the effects that can increase the quality by adding visual these early decisions have. And may receive at least 300 lux for at least in fact, in many ways … it’s 50% of occupied hours. Designers can interest. freed them up from a long-term use this metric to help determine the commitment to electric lighting A main technique used to create comfort- right number and location of win- and the idea that … these spac- able and pleasurable environments is to es can be broadly daylit for the dows, the best ceiling heights, and the focus on illuminating the building sur- most part versus being broadly best floor plate depths. electric[ally] lit. And that really is faces in a space—treating them as “light a change in practice over the last • Annual solar exposure (ASE) de- sources” that reflect light to provide vis- few decades. scribes the percentage of a space that ibility. It’s important then to pay atten- “We usually have completed that will receive too much direct sunlight tion to the reflectance values—which are before we sit down with a light- (which can cause both visual and ther- based on material color—of the surfaces ing designer because oftentimes mal discomfort), defined as at least in the space. To avoid creating high lev- we don’t bring them in until els of contrast, surfaces with drastically we’ve already done a little bit 1,000 lux for at least 250 occupied of a massing study and already hours per year. Note that ASE is not different reflectance values should not started to understand the gen- a direct measure of glare or thermal be placed together. Dark materials can be eral footprint of the building on discomfort, but is only an indicator used to accent a room, but if too many of the site. But this becomes a tool for our dialogue about what de- the surfaces are dark, it will require more of possible glare or thermal comfort cisions we’ve made to date and issues. Designers can use this metric light—and more electricity—to achieve then what decisions lie ahead of during early analysis to determine an adequate level of brightness. us so that we can talk together about using the attributes of the which areas will receive too much di- And because humans mostly look at ver- site to really maximize daylight- rect sunlight and to evaluate the effec- ing on the project.” tical surfaces like walls, these should be tiveness of daylight control measures lighted first, and the ceiling next. Floors like shading devices or glazing with should be lighted last—as humans rare- reduced visible transmittance.

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ly look at floors. And where downlights are used to light the floor, it’s important to use fixtures that also direct some light up. This reduces the potential for glare caused by the contrast of a bright light source against a darker ceiling.

In spaces where occupant focus and attention are important, like learning and work environments, it can help to provide a more simplified, uniform field of view. Because a very small portion of human vision is focused on the central area of the field of view, movement or glare at the periphery of the field of view can automatically catch the eye and divert attention away from tasks like reading. The eye will move constantly and involuntari- ly back and forth between peripheral dis- tractions and central vision focused on a task, causing eye fatigue.

9. Layer light Designers can apply light as an architectural “material” to create effects that shape the spatial experience of an environment and affect the mood and perception of occupants.

For example, lighting design that incor- porates different layers of light creates an interesting, comfortable, and flexible environment. There are three standard layers or categories of light:

• Ambient lighting is generally a uniform, base layer that provides general, overall illumination to a space. Photo: Andrea Calo When designing the Austin • Accent lighting, sometimes referred to Harris explained how great lighting de- Central Library, by Lake|Flato as decorative lighting, is used to high- sign could even go beyond creating com- Architects, the project team focused on the concept of fort to cause delight. “Often there are light points of interest in a space, like quality of light and set a goal an artwork or architectural feature. things that can happen with light that of making the project one of help create a sense of wonder and awe the best daylit buildings in the • Task lighting provides illumination in certain ways,” he said. He added that, world. for the specific tasks that occupants though this isn’t necessarily the primary perform in a space. Table and floor goal, it is always very pleasant and ap- lamps, desk lamps, and bathroom pealing when the lighting, having been vanity lighting are examples of task carefully crafted, adds a human touch to lighting. the architecture.

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it’s now possible to produce LEDs that 10. Reduce ambient, provide INSIGHT task give the occupant the ability to control the color temperature of the light source, Bob Harris, FAIA, principal One common strategy for achieving great- as well as the spectral distribution. at Lake|Flato Architects, er efficiency is to provide a reduced level described how a goal to maxi- of ambient light in a space, and then pro- This is important because it allows occu- mize the quality of daylight at pants to tune the electric lighting in their the Austin Civic Library was vide users in that space the ability to fo- achieved and the impact it cus higher levels of light on areas where space, depending on the time of day, to had on the users: tasks are being performed. An example create optimal conditions for circadian stimulus. For example, during the day, “We really thought this goal would be individual task lamps on desks would be a worthy goal for in an open office space. electric lights can be tuned to a cooler, ourselves—to help create a neutral color temperature like 4,000 de- sense of how we want to shape Lighting the walls and ceiling of a space grees Kelvin (4,000K), and in the evening the architecture and the whole approach to it. We worked to produce a lower ambient light level they can be tuned to a warmer tempera- with lighting designers and can also contribute to visual pleasure by ture like 2,700K. (The lower the color tem- natural daylighting experts and making a space look alive and balanced. perature of the light, the closer it is to the engineers and others to help It also makes the space more flexible be- red end of the visible spectrum and the reinforce those goals from the cause the light is less tied to a certain set outset. We were able to do a lot “warmer” the light feels.) This creates a of that visioning and goal setting of tasks. more comfortable visual environment upfront, and then put in the time and protects the occupant from exces- and attention that was necessary sive levels of cool, blue light, which, as to creating the right architectural 11. Leverage technology to responses to the lighting. And discussed earlier, can have a negative im- to bring both the natural and protect health and increase pact on the sleep cycle. artificial lighting to the table to comfort inform the building form, the footprint, everything about the Light sources that provide a wider spec- 12. Specify high-quality LEDs way the program laid out on the trum of light promote comfort because site, and to help shape the right they increase the occupant’s ability to Because of these advanced capabilities, experience for the users. LEDs have become the default source for see objects in true color, the way they’re “It really was our central meant to be seen. One reason daylight is electric lighting in almost every applica- departure point for all those such a pleasant light source is that it pro- tion—valued as much for their ability to decisions—the idea of quality create comfortable, pleasing light condi- of light. It opened up this last vides the full spectrum of light, unlike year and has been overrun with tions as for their energy efficiency. most electric light sources (like incandes- citizens and people enjoying the cent and fluorescent lamps), which only library in new ways that they'd However, manufacturing of LEDs is in- provide portions of the spectrum. never had access to, at least in consistent, and not all LED products are Austin, or I’d say probably in the state.” However, LED technology has now ad- created equal. Just because a light source vanced to the point where high quality is an LED doesn’t automatically mean it’s He explained that, although LEDs are able to provide the full spec- a good light source. In short, the quality libraries are often thought of as quiet, private, darker spaces, the trum of light, or close to it. Additionally, of an LED product depends on the sup- Austin Civic Library “was basically designed to be enlivened by light and to create a quality of the modern library that really functions more as a civic and so- cial meeting grounds for people to come together around books but also around education and collaboration, and for meeting their neighbors and being Image: Phrood. License: Public domain. together—a place that I think Different color temperatures are used to create environments with different effects. Warmer maybe libraries haven’t always colors (lower temperatures) are used to create relaxing environments while cooler colors (high- been in the past.” er temperatures) are used to create environments that have an energizing effect. In general, color temperatures below 3,200K are considered “warm” because they contain more reddish or yellowish tones. As the color temperature increases, they contain more blue and become increasingly “cool.”

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plier and the quality controls and root absorb a large portion of the lumens technologies that supplier uses. There are offered by the lamp, would not be ef- several different factors that are used to ficacious. determine the quality of a light source. INSIGHT It can quickly get complicated, so having • Layout efficacy refers to how well the a lighting specialist on the team to help fixtures in a space are located to prop- Susan T. Morgan, AIA, former- erly illuminate surfaces and tasks. ly an architect at MSR, de- navigate the complexities is important. scribed her experience work- • Room efficacy refers to how well the ing with a lighting designer on a 700-seat multi-purpose 13. Reduce power, time, characteristics of a space enhance the auditorium for a library: lighting. or both “This is the kind of space where When pursuing lighting energy-perfor- • Task efficacy refers to how well the il- generally we have to control daylight because … it’s the- mance goals, it can be useful to think in lumination supports the task at hand. ater performances, it’s music terms of the equation: energy = power × Ideally, only the surfaces that need to performances—you don’t think time. The power variable has to do with be illuminated for occupants to per- of having to bring daylight into a space like that. But because the the efficacy of the design (see definitions form their tasks would be illuminated. client wants to use it for other of efficacy below), and the time variable events, we started having very has to do with how long the light sources 14. Provide controls early conversations in pre-design are on. about ‘Is there a way to bring In addition to optimizing the efficacy of daylight in?’ Levitt explains, “If you can reduce either the architectural space and specifying “And having a working charrette power or time, you’re going to reduce en- high-performance light sources, project [with the lighting designer], we ergy. If you can reduce both, you’re going teams can use controls to further reduce actually talked through the dif- to reduce a lot of energy. It’s also really in- ferences. Typically as architects energy use. In fact, some lighting design- we look at things from a form teresting to note that if you can reduce ei- ers argue that the only way to get a light- basis—so, ‘What if we put the ther one a lot, then the other one matters ing system to save energy, regardless of windows on the side, what if we put the windows on the top, a whole lot less. So if you can reduce your how efficient the light sources are, is to what is the shape, what is the time, so that you only have lights on for combine them with proper controls. aspect?’ And to bring Brennan a half hour a day, then how much power [the lighting designer] into that those use is much less important.” Referring back to the “energy = power conversation allowed us to really × time” equation, the purpose of using talk through not just, ‘What if The following five scales of efficacy— controls is to reduce the “time“ variable we do it on this side?’ but what are some of the outcomes … in which each affect the “power” variable of as much as possible. In short, the lights terms of quality of light—the col- the equation—can serve as a guide to help should either be dimmed or turned off or, and the hue, and the intensi- project teams discuss and understand the whenever possible. ty? How easy or how difficult is it various ways different lighting products for us to manage daylighting on each of these facades? and strategies impact the efficacy of the Common types of controls used to reduce overall lighting design: lighting energy use include: “So that allowed us … at a kind of deeper level to really kind of • Lamp efficacy refers to the amount • photo sensors, which dim or turn think through possibilities, but of light a lamp supplies for a given lights on or off in response to the to also understand the outcomes a little more fully than you typi- amount of daylight in a space amount of electricity. It is measured in cally would during a pre-design lumens per watt, or LPW. phase, so it helps establish goals • occupancy sensors, which dim or in a more specific and deliberate • Fixture or luminaire efficacy refers turn lights on or off in response to the way than sometimes you would to how efficiently a luminaire directs presence of occupants in a space be able to.” the light offered by the lamp. For ex- • time clocks, which dim or turn lights ample, if the lamp offers a thousand on or off based on an automated sched- lumens, how well does the luminaire ule that is programmed according act to direct those thousand lumens in to occupancy patterns or the daily a way that’s useful? A luminaire with sunrise and sunset times for the proj- black inner surfaces, which would ect’s geographical location

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• a demand-response system, which dims or turns lights on or off based on communications from the utility regarding increased demand on the grid

It’s critical to design controls that are specific to the particular project. The project team should work with the owner to develop a clear, space-by-space control intent based on the use, occupancy, and daylight autonomy of each space. In private, single-occupant spaces, the controls might be pretty straightforward. But designing controls for public areas and shared, multi-occupant spaces can be complicated.

Automatic controls, which may be re- Photo: Brandon Stengel ular group of users and schedules, cen- The Louisville Free Public quired by code depending on project lo- Library South Central Region- cation, should ideally be designed and tralized control can streamline efficiency al Library, designed by MSR, calibrated so that they are as seamless by reducing the number of people who provides an example of how as possible. For example, when using oc- need to engage with the system. How- daylighting and artificial lighting can be balanced to create a cupancy sensors, project teams should ever, in public buildings, with a varying quality environment. specify dual-technology sensors that de- set of uses and many different users oc- tect both ultrasonic and infrared signals. cupying the building at irregular times, a These operate with fewer issues because more simplified, intuitive, decentralized they require the absence of both types system of controls is needed to provide of signals before dimming or turning off for occupant comfort. lights, but require the presence of only It can prove valuable to have the lighting one type to turn lights on. It’s also import- system communicate with the building’s ant to give occupants the ability to easily energy management system to produce adjust or override the sensors remotely if detailed reports on the use and energy they need to. consumption of the lights. Facility man- Whether or not it makes sense to integrate agement staff can use this feedback to lighting controls into the central building monitor whether the lighting system is management system will depend on a va- operating correctly or to locate the issue riety of factors, such as project scale and if something’s not working as expected. typology, budget, users, and the facility staff’s familiarity and comfort with the system. For example, in projects with a specific and fixed set of uses, and a reg-

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SIDEBAR: LED BASICS

What Is an LED? Energy efficiency

• LED (light emitting diode) lighting, or solid-state • Energy efficiency in lighting is measured in the amount lighting (SSL), uses semiconductors (LED chips) to of light produced (lumens) per watt of energy produce light as current flows across it. This produces consumed, or lumens per watt (lpw). energy, as photons of light, and also releases some heat. Using different semiconductor materials or engineering • Luminous efficacy (sometimes called source efficacy produces different colors of light. White light can also be or even LED efficacy) is the efficacy of just the LED chip created by using combinations of red, green, and blue before the optics, driver, and other electronics are LEDs. added. Addition of the driver and other components lower the efficacy of the luminaire significantly. Manu- • LED lamps (sometimes called bulbs) are made up of facturers often tout the amazing efficacy of their chips, the following components: an LED chip or chips, a heat which can be confusing. Cree, for example, surpassed management system (heat sink), electronics, and optics. 300 lpw for one of its chips in 2014, but luminaires rarely reach 110 lpw. • LED luminaires (light fixtures) include the LED lamp and components required to connect the lamp to the • Luminaire efficacy is a measure of the efficacy of the power supply, protect the lamp, and distribute the light. entire luminaire (or fixture),after the optics, driver, and other electronics are added. It is a measure of the amount of power a luminaire consumes per light output of the entire unit. LED luminaires with high Optics color rendering index generally have lower efficacies. • The light produced by an LED shines in one direction (unlike an incandescent lamp), so it has to be directed and diffused by optics for specific end uses. Color and Quality

• Primary optics cover the LED chip to help improve light • LED color and quality are measured by the color output. Phosphors that are critical for changing “blue” rendering index (CRI) and the correlated color light to warmer reds and yellows are often added to temperature (CCT). these optics. • CRI is a measure of how accurately a light source • Secondary optics typically adjust the beam angle or renders the colors of an object compared to a reference create a more diffuse light. source. It is based on a scale from 0 to 100, with 100 being the most “accurate” color. An incandescent bulb has a CRI of 100, for example. LED CRIs are now above 80, with some reaching as high as 98. Drivers and dimmers • CCT (measured in Kelvins) is based on the colors • LEDs run on direct current (DC) and usually require a given off by an ideal metal heated up to the point of driver, or power supply, to convert alternating current glowing. Most lighting falls in the 2,000K (orange-yellow (AC) from the utility to DC. Dimmers and building auto- candlelight) to 6,500K (blue midday sunlight) range. In mation can also be integrated into the luminaire. In an general terms, color temperatures below 3,200K are LED replacement lamp, the driver and other electronics considered “warm” because they contain more reddish are contained in the base of the lamp. or yellowish tones. As the color temperature increases, they contain more blue and become increasingly “cool.” • Other LED luminaires use external drivers, either Light quality can vary between brands, and there are constant-current drivers that pair one light per driver, no definitive color temperature cutoffs, but 3,200K to or constant-voltage drivers that connect to multiple 4,500K are sometimes labeled neutral or cool white, lights connected in parallel. Drivers are critical to the and those above 4,500K are sometimes called cool efficacy and overall performance of an LED luminaire. white or daylight. • Dimming LEDs can be done in a number of ways, either through analog systems that vary the current or through digital systems using the international standard Digital Addressable Lighting Interface (DALI).

• Drivers and dimmers have to be compatible with one another to maximize performance and reduce the chance of getting “hum” or flicker in the LEDs.

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15. Integrate interior and 17. Conduct post-occupancy INSIGHT exterior lighting evaluations Brennan Schumacher, lighting Especially on public projects, exterior It’s always a good practice to visit projects designer and associate prin- lighting providing nighttime visibility is after occupancy to verify that all systems cipal at Mazzetti + GBA, gave important for way-finding, security, and are operating as designed and to address an example of how educating the building manager about safety, but if it is not carefully designed or any issues that occupants may have. This how to engage with the if too much light is provided, it can cause is especially important when it comes to lighting control system led to glare, light trespass, and habitat disrup- lighting systems, as they have a signifi- further energy savings: tion. cant impact on usability and comfort. “We did the J. Craig Venter Insti- tute a few years back.… We had Although often exterior lighting is consid- On larger buildings with more complex all the dim levels topped out at ered more as an afterthought, it can have light systems, it’s important to go back 75% so none of the lights could a significant impact on the experience after the building has been occupied for come to full brightness, and we told the building manager, if you of the building. Architects should work a few months and fine-tune the program- take that down 1% a day until together with the lighting designer, the ming to match the actual use of the build- you find people starting to say it landscape architect, and engineers to de- ing as precisely as possible. doesn’t feel like we have enough velop a holistic strategy in which interior light, and then ratchet it back up Some of the most common complaints re- 3 or 4 points—they feel like they and exterior lighting interact seamlessly have great light, and you just lated to lighting gathered during post-oc- and connect indoor and outdoor space. saved 12% more energy. cupancy evaluations have to do with occupancy sensors. If the sensors are not “The programming side—I can’t stress it enough—it’s really, 16. Commission the system operating correctly, occupants will often really important, and for better Once construction is complete, it’s cru- get frustrated and override them. It’s im- or worse, it often comes down cial to commission the lighting system to portant then to resolve any issues there to the individual [who’s] actually may be with the sensors to make sure that onsite. … So we try to be onsite ensure that all the various components when the programming is hap- have been installed and programmed they continue to operate and contribute pening, and I find that that adds correctly. The more complex the lighting toward energy savings. a lot of value. We can answer all design—projects with multiple sophisti- their questions right there on It is also critical to work with the build- the spot, they hear more about cated control schemes—the more import- ing management staff to make sure they our design intent, and I think ant commissioning becomes. they care more when the person understand how the controls and various [who] designed it is working with The commissioning process can often features of the lighting system work. The them rather than just sending uncover small issues that seem minor more informed they are about how the them spreadsheets from 600 miles away.” but can result in significant negative im- system works, the more likely they are to pacts on efficiency and occupant health engage with it to make sure it’s operating and comfort. For example, an occupancy at peak performance and that maximum sensor may be installed too close to an air energy savings are being captured. diffuser, which will prevent that sensor from dimming or turning off lights when it should. Or a sensor that was originally calibrated according to the surface reflectance values in a room may need to be re-calibrated if the materials in that room have been altered and affect reflectance.

Lighting Design for Health and Sustainability 18 BuildingGreen Spotlight Report

Continuing Education To receive continuing education credits, take this quiz online at www.buildinggreen.com/spotlight/lighting.

1 AIA LU|HSW, 1 GBCI CE hour

INSTRUCTIONS: efficiency.

If you purchased this report, or if you are Learning Objectives a BuildingGreen Premium member, you Upon completion of this course, partici- can get continuing education credits by pants will be able to: successfully completing this quiz on our website. 1. Describe how high-quality lighting

design dovetails with sustainability ® For BuildingGreen to automatically report by improving energy efficiency and your CEUs, you will need to add your AIA supporting occupant health and and/or GBCI identification info to your well-being. profile, at www.buildinggreen.com/user. 2. Explain the sustainability benefits of daylighting, including increased energy efficiency and wellness, Description along with the drawbacks of poor What do we mean when we say sustain- daylighting design—such as ex- able lighting? In this course Building- cessive glare and solar heat gain, Green takes a closer look at lighting as which can reduce energy efficiency an essential element in quality environ- and cause occupant discomfort. ments that support health and wellness 3. Define basic lighting terms, such as while reducing energy use. “play of brilliance,” “spatial daylight The functionality of a building is largely autonomy,” and “color rendering dependent on the quality of its lighting, index,” along with the relevance of which is often treated as a secondary con- such lighting terms to improved ef- cern, taking a back seat to form-making. ficiency and occupant wellness. Lighting design can have either positive 4. Understand the expanding role of or negative effects on people, especially high-quality LEDs in sustainable in the spaces where many people spend lighting design, and demonstrate a lot of time. In order to safely and com- proficiency with the vocabulary of fortably perform their tasks, occupants LEDs relating to efficacy and light need lighting that provides adequate vis- quality. ibility without causing discomfort or distraction. Take a look with BuildingGreen at how quality lighting conditions in buildings not only provide functional and comfortable spaces, but can also achieve

Lighting Design for Health and Sustainability 19 QUIZ QUESTIONS

1. In order to safely and comfortably perform their 6. Some chemicals of concern in lighting products tasks, occupants need lighting that provides are compact fluorescent lights, which contain adequate visibility without causing ____. highly toxic mercury and LEDs that contain copper which can create an environmental hazard if it  a. Thermal mirages accumulates in ____.  b. Faintness  c. Discomfort or distraction  a. Waterways  d. Tint and texture  b. The air  c. Outdoor shoes  d. Pets 2. Which of the following are influenced by lighting design? (Choose all that apply.) 7. According to the Energy Information Administration,  a. Comfort in 2012, lighting in U.S. commercial buildings  b. Usability required ____ kWh of electricity—about 17% of total  c. Health commercial building electricity use in the nation.  d. Environmental impact  a. 156 trillion  b. 212 billion 3. Like acoustic design, ____ can have either positive  c. 758 million or negative effects on people, especially in the  d. 124 million spaces where many people spend a lot of time, like schools and offices. 8. Play of brilliance refers to lighting that sparkles,  a. Aperture shimmers, or shines, such as chandelier or sunlight  b. Lighting design reflecting on ____ .  c. Window treatments  a. Water  d. Wall washing  b. Windows  c. Walls 4. Studies have shown that in healthcare settings,  d. Workspaces poor lighting conditions can hinder the way people work, learn, and heal by causing ____. (Select all that apply) 9. The three standard layers of light that creates an interesting, comfortable, and flexible environment  a. Distraction are ____, accent, and ambient lighting.  b. Discomfort  c. Fatigue  a. Task  d. All of the above  b. Daylight  c. Sensor-controlled  d. None of the above 5. Project teams should avoid ____ by not over- lighting, prevent light trespass, and consider potential impacts of lighting on the plant and 10. Common types of controls used to reduce lighting animal life of the surrounding ecosystem as well as energy use include: (Select all that apply) on neighboring buildings, places, and communities.  a. Photo sensors  a. Sound barriers  b. Occupancy sensors  b. Integrated complexities  c. Time clocks  c. Daylighting  d. Demand-response system  d. Light pollution  e. All of the above

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