Spotlight lighting-design

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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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 & Associates, advises, “Don’t design for energy
savings; design well, and the result will
be incredible energy savings.” By creating quality lighting conditions in their
buildings, not only will project teams
provide functional and comfortable
spaces, but they’ll also achieve efficiency.
And because the lighting in a space has
such a significant impact on how people use that space and how they feel
while in that space, it is critical to the
human-health component of sustainability. Lighting affects not only the performance and productivity of occupants
but also, more critically, their well-being.
High-quality lighting, beyond providing
basic comfort, can protect and promote
health.
The effects of lighting
Like acoustic design, lighting design can
have either positive or negative effects
on people, especially in the spaces where
many people spend a lot of time, like
schools and offices. Research has shown
positive correlations between quality
Photo: Lara Swimmer
lighting conditions and improved productivity as well as higher student test scores.
Studies also suggest that quality lighting
has positive impacts in healthcare settings—for example by improving the
mood and perception of both staff and
patients. Conversely, poor lighting conditions can hinder the way people work,
learn, and heal by causing distraction,
discomfort, and fatigue.
The third floor reading space
of the Madison Central Public
Library, designed by MSR, is
designed to receive an
abundance of daylight.
Getting the light right is crucial. As Bob
Harris, FAIA, principal at Lake|Flato Architects put it, “If you’re not doing a good
job with lighting, you’re not going to be
doing a good job architecturally.” He explains that lighting is often treated as a
secondary concern, taking a back seat to
form-making. Too often, he argues, architecture is conceived of as an object to be
viewed from a detached position rather
than as a habitat to be experienced and
lived in.
Lighting Design for Health and Sustainability
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And of course, in addition to affecting
usability, comfort, and health, the way a
building is lit also affects its environmental impact.
What do we mean when we
say sustainable lighting?
And some LEDs also contain copper,
which can create an environmental
hazard if it accumulates in waterways.
(LEDs, despite their long life, will
eventually need to be replaced. They
can be disposed of in regular landfills,
as they are not currently regulated as
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,
and communities.
• Life-cycle impacts of lighting products—Lighting designers should work
with manufacturers over time to reduce the embodied energy and carbon cost of fixtures, luminaires, and
lamps. To help extend the life of the
building and further reduce environmental impacts, when appropriate the
lighting should be designed so that it
can be easily retrofitted and adapted
to align with future technology advances. (See Modular LED Lighting
Enters the Mainstream and Product as
a Service: Buying the Lumen, Not the
Lightbulb.)
• Chemicals of concern—Project teams
should advocate and work with manufacturers to, over time, reduce the
level of toxic materials in lighting
products. For example, compact fluorescent lights, which contain highly
toxic mercury, have to a large extent
been replaced by LEDs, which do not
contain mercury. However, sometimes LEDs are manufactured with
high levels of lead and heavy metals.
Photo: Mike Knell.
License: CC BY-SA 2.0.
High quality, low energy
The information offered in this report
generally revolves around lighting design
that provides building occupants with the
highest-quality illumination possible—
providing comfortable and safe environments in which to complete their tasks—
while using as little energy as possible.
As part of an integrated
approach to sustainable
lighting design, project
teams should avoid lighting
strategies that contribute
to light pollution.
According to the Energy Information Administration, in 2010, lighting in U.S. commercial buildings required 297 billion
kWh of electricity—about 22% of total
commercial building electricity used in
the nation. But technology has been rapidly evolving, and it’s becoming ever easier and more cost effective to drastically
reduce the amount of energy consumed
by lighting. In fact, LEDs have become
so efficacious that additional gains in
efficiency are small. The point has been
reached where many in the lighting industry, who now see energy efficiency as
a given, are turning most of their attention to the human-health component of
sustainability and the ways that quality
lighting can support it.
Lighting Design for Health and Sustainability
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Designing Sustainable Lighting
In pursuit of quality sustainable lighting,
a good place for any project team to start
is with a refresher on the fundamentals
of how light and human vision work. A
good grasp of the relationship between
light levels and what people actually see
can go a long way toward helping the
team make design decisions that will contribute to efficiency, health, and comfort.
Understanding the difference and relationship between “measured light”—for
example, the amount of lumens that a fixture emits—and “perceived light”—what
a person actually sees—shifts the focus
toward designing for effects of light and
away from engineering for light levels.
1. Learn the basics of light
As the members of a project team may all
have different levels of knowledge and
experience with lighting, it can be useful
and efficient to devote some time, at the
beginning of the design process, to getting
everyone up to speed and on the same
page.
One option is to have the lighting designer give a brief educational presentation to
the entire team. This would also allow the
lighting designer to catch everyone up on
the latest information about lighting techniques and technologies. (For example, a
basic understanding of how LEDs work
and how to evaluate the quality of different products can be very useful. See our
previous feature article, LEDs: The Future
Is Here.) The lighting industry is a rapidly
evolving and increasingly complex field,
and knowledge that was current only a
few years ago may already be outdated.
Brennan Schumacher, lighting designer
and senior associate at Mazzetti + GBA,
told BuildingGreen that on every project
he works on, he gives a presentation to
the entire project team early in the process. This allows him to educate them
about his design perspective and approach to sustainable lighting design. “I
think that adds a lot of value for the owner and the architects,” he said. “I get a lot
of comments from the civil engineer, the
landscape architect, or the mechanical
LEARN THE LINGO:
Lighting Literacy
• Color Rendering Index
(CRI): a metric that describes
how faithfully a light source
renders the true colors of objects and spaces (natural light
has a perfect index of 100)
• Correlated Color temperature (CCT): often shortened
to “color temperature” or
“Kelvin temperature,” it is
used to described the color
output of a light source—
Common CCT values include:
»» 2,700K: warm, slightly
yellow tone, used to create
relaxing environments
»» 4,000K: neutral white tone,
used to create “balanced”
environments that allow
for both relaxation and
concentration
»» 6,500K: cool, slightly
blue tone, used to create
environments that have an
energizing effect
• Glare: a vision impairment
caused by either direct or
reflected intense light; occurs
whenever there is a high contrast between a light source
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 evaluating 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
Image: J.C. Walker. License: CC BY-SA 3.0.
It is useful for architects to know the definitions of different lighting metrics and how they relate.
Lighting Design for Health and Sustainability
• Wall washing: a lighting effect where a wall is illuminated so that surface irregularities are minimized, making
the surface appear smoother
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engineer about things that they have not
thought about in regard to lighting.”
Examples of some basic information that
might be covered in such a presentation
include the following.
What light is, and how it interacts
with building surfaces
• Light consists of photons, invisible
particles that are only perceived via
their interaction with matter. This is
what’s called light propagation—the
reflection of light off of surfaces. What
people see as light is the reflected color of surfaces.
• Light reflects differently based on the
color and structure of the surface at
the microscopic scale. Smoother surfaces—like glazed tile—produce more
direct reflections of light and are described as “specular.” Incident light—
the light that falls on a surface—is reflected back at close to the same angle
at which it strikes the surface. Matte
surfaces—like unfinished wood or
stone—are rougher and produce diffuse reflections of light because the
incident light that hits it is scattered,
meaning the light reflects off different
portions of the material at different
angles. The darker the color of the surface, the more light is absorbed and
the less is reflected.
How humans perceive and are
affected by light
• Humans have evolved over a long period to see the way they do, relying, for
most of their existence, on the sun as
their primary source of light. (Fire was
discovered in the Stone Age and then
combined with reflectors around 200
CE for use as a light source. Electric
lighting only started to become common in the early twentieth century.)
• The lenses, pupils, and irises of human
eyes control how much light is transmitted to the rods and cones at the
back of the eyes. The rods and cones
respond by sending a signal through
the optic nerve to the brain, which
then communicates what is seen.
Vision is not about the amount of light
a person sees but about what that
person perceives in the surrounding
environment.
• Humans have, at the backs of their
eyes, photosensitive retinal ganglion cells that send different signals
to the brain based on the light they
are exposed to, impacting hormone
production. This means that light affects a person’s physical, mental, and
behavioral states. For example, when
exposed to bright blue or white daylight, the body suppresses the production of melatonin, making a person
alert and awake. When exposed to
the warm red and yellow tones of the
setting sun, the body increases production of melatonin, which makes
a person relaxed and induces sleep.
This light-and-dark cycle is known as
circadian rhythm.
The factors that affect visibility,
which has little to do with light
levels
• the luminance, or reflected light,
in the space that our eyes perceive
• the contrast between different
luminance values in a space
• the size of the objects in a task being
performed
• the duration of time spent
performing the task
INSIGHT
Brendon Levitt, associate
at Loisos + Ubbelohde,
described the importance of
understanding the conceptual relationship between
the task being performed in
a space, the material in that
space, and how that space is
illuminated:
“I think that’s either misunderstood or not well understood
in a lot of cases. Understanding
the room as light fixture is a
critical piece.
"We were in a project where
we’d been going through this
with the architect and talking
about these corridors and how
the lighting would work with it,
and we had a strategy where
we were going to illuminate
the ceiling with an uplight in
order to get a nice diffuse light
throughout the corridors.
"Then the interior designer
came on and decided that they
wanted to have a really dark
walnut ceiling. And basically
they completely absorbed all
the light we were throwing up
onto the ceiling and negated all
the work that we did. So we had
to redo the whole design based
on that decision.
"I don’t think the interior
architect had any idea that that
would affect the lighting. So it’s
a combination of understanding what surfaces are being
illuminated and what materials
those are because in effect, by
illuminating those materials,
you’re creating another light
fixture."
The definitions of different lighting metrics and how they relate
• Luminous flux, measured in lumens,
refers to the light output of a fixture.
• Illuminance, measured in lux or
foot-candles, refers to the amount of
light that falls on a surface.
Lighting Design for Health and Sustainability
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• Luminance, measured in candelas
per square meter (cd/m2), refers to the
amount of light reflected off of surfaces that our eyes perceive. (The candela
is the base unit of luminous intensity,
which is the power emitted by a light
source in a particular direction.)
Brendon Levitt, associate at Loisos + Ubbelohde, explained why it’s important to
understand these basic concepts and the
general relationship between light sources and architecture. “It really translates
as, ‘What particular surface are you illuminating, for what purpose?’” he said. “I
think if more architects could ask themselves that question, they’d get to the
bottom of the lighting design a lot faster.
They’d sort of answer a lot of questions
for themselves about what they’re trying
to accomplish. Because there always has
to be a surface that’s illuminated.”
2. Work with a lighting
design consultant
Including a lighting design consultant on
a project team is a great way to ensure
that lighting concerns are integrated into
the design.
Although in the past architects relied
on lighting designers mainly for help
specifying fixtures, the lighting designer’s
role has evolved over the past decade or
so as architectural practice shifts toward
more integrated approaches. Architects
now often collaborate closely with lighting designers, starting in early phases of
design, when massing decisions, which
significantly affect opportunities for daylight, are being made. And, increasingly,
project teams are looking for ways to integrate lighting considerations from the
very beginning of the design process,
rather than treating it as a kind of ornamentation that’s added on to a design.
Great lighting design often appears seamless, and some may misinterpret that as
meaning the task was effortless. The reality, however, is that achieving quality
lighting often requires an extensive, iterative process and involves balancing
a range of factors. The expertise of a
lighting designer can go a long way toward making that process valuable and
effective. But in order for this to happen,
it’s important to treat lighting designers
as collaborators rather than just having
them run calculations or specify fixtures.
A skilled lighting designer will be able to
help blend together all the various, interdependent elements that affect the quality of lighting.
INSIGHT
Brendon Levitt, associate at
Loisos + Ubbelohde, described
the iterative process involved
in lighting design:
“You have to go through a few
times. Very rarely is it possible
to get it right on the first try. The
reason for that is that there are a
lot of variables here, and it’s not
a determinative solution. You
can’t say, ‘I need 62 foot-candles
on these three surfaces and so
the only solution is this right
here.’ There’s about a million
different variables between the
aesthetics, the architectural
intent, the task, the occupants’
expectation, the budget, the
controls, the technology that’s
available, the code restrictions,
what your local jurisdiction is,
how much light egress you get,
what impact you have on other
habitats, it goes on and on and
on. And so all these different
things mean that you’re going
through this multiple times and
you’re looking at it from multiple
perspectives each time.”
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.
Lighting Design for Health and Sustainability
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For example, Susan Morgan, AIA, an architect at MSR, explained that her firm
seeks to collaborate with lighting designers who have a facility with both the
quantitative and the qualitative 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.”
3. Start early
As is true with most aspects of high-performance design, it is crucial to start considering lighting early in the process. The
best way to maximize the value offered by
a lighting design consultant is to involve
them from the beginning of the project.
Clanton explained that, in terms of workflow, it is ideal for the lighting designer to
be involved early to talk with the architect about their ideas for materials, colors,
and different scenes. She described this
process as a kind of walkthrough of the
building with the architect to understand
the vision for how the spaces should be
experienced and to discuss how the lighting can support it.
Additionally, as energy codes continue to
evolve and as the requirements relating
to lighting change, it can be helpful to
have a lighting designer involved early
to assess and explain how the code could
potentially impact design decisions. In
locations with more progressive energy
codes, there may be more stringent rules
that restrict the number of design solutions available. It’s important that the
project team integrate these parameters
into the discussion before spending too
much time and money developing a design that will end up not being compliant.
Image: Lake|Flato Architects
Having a lighting design consultant involved from the early stages of design
can also help the project team ensure that
they are pursuing cost-effective solutions.
An experienced lighting designer can help
a project team assess factors like installation, programming, and maintenance to
determine if a given lighting technology
or strategy will be financially sustainable.
A section diagram explaining the
daylighting strategy used at the
Indian Springs School, designed
by Lake|Flato Architects.
4. Communicate effectively:
a way to talk about what
light can do
When collaborating, it can be helpful for
a lighting designer and an architect to
have a common vocabulary to discuss
how light can be used and to what effect.
This contributes to a more informed dialogue about how the project’s lighting
design impacts energy performance and
occupant health and comfort, which in
turn results in a more efficient and effective design process.
Richard Kelly—who is generally recognized as the first modern lighting designer—came up with a set of categories of
lighting effects in an effort to help the architects he worked with understand lighting design. Many contemporary lighting
designers have adopted these terms, or
variations of them, and find them to be
Lighting Design for Health and Sustainability
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effective when thinking together with
project teams about light:
• Play of brilliance—refers to lighting
that sparkles, shimmers, or shines.
An example would be a chandelier or
sunlight reflecting on water.
• Ambient luminescence—refers to
large washes of light, generally coming from the ceiling or walls. It’s what
most people mean when they say “ambient light.”
• Focal glow—refers to lighting meant
for a specific task in a space. An example would be spotlights on an artwork
in a museum, or a task lamp on a desk
in an office.
Lighting designers and architects use
these basic categories as layers that can
be overlapped and combined in different ways to both adequately illuminate a
space and produce visual interest, which
is important for comfort.
5. Start with the sun
The common view among lighting designers concerned with meeting sustainability goals of efficiency, health,
and comfort, is that daylight is where
all lighting design should start. After all,
daylight is free, abundant, and has positive effects on human well-being. For
example, exposure to daylight boosts
the body's production of vitamin D, a
healthy supply of which is believed to
promote bone growth and prevent illnesses such as breast and colon cancers,
multiple sclerosis, and depression.
And because designing for daylight has
implications for other major components—structure, mechanical system,
landscape, materials, etc.—it is also the
most logical place to start when taking an
integrative design approach.
“The first thing I want to know as the
electric lighting designer is: where is the
daylight coming from?” said Levitt. “I
INSIGHT
Brennan Schumacher, lighting
designer and senior associate
at Mazzetti + GBA described a
successful project he worked
on that demonstrates the
value of a design approach
that integrates lighting early
in the process:
“We did the Indian Springs
school with Lake|Flato. It’s a
little school outside Birmingham,
Alabama—a series of classrooms
and a couple offices. When they
started the design, it was small
classrooms and windows on
both sides of the classrooms.
They were analyzing this. … This
is one where we were involved
early on in the process, and we
said, ‘What would you think if we
popped the top and put a roof
monitor up there?’
“They weren’t loving the idea
right away, but they were open
to it. So we ran a series of calcs
and renderings kind of showing
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.
Lighting Design for Health and Sustainability
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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 nearly 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.
Project teams should also keep in mind
that all electric lights produce heat—either through radiation or convection—
and that this heat all eventually ends up
as heat in a space. So in addition to requiring more electricity, excess electric
light fixtures also raise energy use by increasing the cooling load of a space.
Design for daylight can also often provide occupants with views to the outside,
which, because it relaxes the visual system, contributes to health and comfort.
Where direct views to the outdoors are
not possible, reflecting dynamic, natural
light into the space can also support a
comforting and beneficial connection to
nature. The more exposure people have
to views and daylight, the better aligned
their circadian rhythms are to the natural
dark-light cycle. And research suggests
that maintaining a consistent circadian
rhythm may help improve overall health
and prevent chronic diseases.
Image: Qais Tabib.
License: CC BY-SA 3.0.
Designers can use a number of
different techniques to bring
daylight into interior spaces.
But it’s critical to control the amount of
daylight entering a space, for example by
adding shading devices to windows. Extremely intense direct light and glare on
task surfaces can cause severe discomfort
and make a space unusable. Over-glazing and failure to properly control the
amount of daylight entering a build-
Lighting Design for Health and Sustainability
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ing can also lead to excessive solar heat
gain, causing thermal discomfort and increasing the building’s cooling load. (See
Rethinking the All-Glass Building.)
Steps should be taken to mitigate potential glare, especially during early hours of
the day and in the evening, when the sun
is low in the sky. If occupants draw their
blinds to block glare, they often will leave
them drawn, reducing the energy and
health benefits that would otherwise be
provided by incoming daylight.
It’s also important to evaluate potential
daylight strategies in relation to all sky
conditions—clear, overcast, and partly
cloudy—as any single design approach
will perform differently under each. (For
more information on designing for daylight, see Doing Daylighting Right.)
6. Integrate electric lighting
Once the available daylight has been fully
considered, integrated into the architec-
tural design, and optimized for the space’s
particular use, electric light should be
blended in to augment the natural light
and provide any additional illumination
needed.
In certain instances, it will not be possible to get much daylight into a space.
One example is the low floors of buildings in dense urban settings. In such cases, it does not make sense to spend time
and money to develop strategies based
on daylight as a primary source. Basic
early analysis tools can be used to study
a project’s site and context and quickly
determine whether daylight will be a feasible option.
7. Conduct early analysis
Project teams can use early analysis tools
(like Sefaira, DIVA-for-Rhino, and Ladybug Tools) to study the impact of the following characteristics, which will lead
to better, more informed lighting design
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
• building form and footprint
• placement and size of windows
• placement, shape, and size of exterior
solar shading
• ceiling heights
• section profiles
Using early analysis tools to understand
which spaces receive daylight—and how
much daylight, and when—can inform
programming, occupancy, and scheduling decisions.
There are two common climate-based
metrics that early analysis tools generate
to describe a building’s relationship with
daylight:
• Spatial daylight autonomy (sDA) describes the percentage of a space that
will receive sufficient daylight—defined as floor area that receives a minimum illumination level for a minimum percentage of annual occupied
hours. For example, an area of floor
may receive at least 300 lux for at least
50% of occupied hours. Designers can
use this metric to help determine the
right number and location of windows, the best ceiling heights, and the
best floor plate depths.
• Annual solar exposure (ASE) describes the percentage of a space that
will receive too much direct sunlight
(which can cause both visual and thermal discomfort), defined as at least
1,000 lux for at least 250 occupied
hours per year. Note that ASE is not
a direct measure of glare or thermal
discomfort, but is only an indicator
of possible glare or thermal comfort
issues. Designers can use this metric
during early analysis to determine
which areas will receive too much direct sunlight and to evaluate the effectiveness of daylight control measures
like shading devices or glazing with
reduced visible transmittance.
If an architect conducts early analysis
to study site conditions and massing options, it can serve as a good starting point
for discussions with the lighting designer about what’s possible regarding use
of daylight and how electric light can be
integrated to augment it. The lighting designer can also, if involved early enough,
help substantiate or improve the assumptions made for early energy assessments.
8. Focus on quality
In terms of creating lighting conditions
that are conducive to human health, wellness, and comfort, the main objective is
providing for visibility, which has everything to do with the quality of light in an
environment and little to do with the actual quantity of light provided.
An environment that feels bright and balanced, in which occupants can easily see
what they need to see and where they are
not distracted or fatigued by excess glare
or contrast, is the baseline requirement
for a quality lighting condition. Designers
can increase the quality by adding visual
interest.
A main technique used to create comfortable and pleasurable environments is to
focus on illuminating the building surfaces in a space—treating them as “light
sources” that reflect light to provide visibility. It’s important then to pay attention to the reflectance values—which are
based on material color—of the surfaces
in the space. To avoid creating high levels of contrast, surfaces with drastically
different reflectance values should not
be placed together. Dark materials can be
used to accent a room, but if too many of
the surfaces are dark, it will require more
light—and more electricity—to achieve
an adequate level of brightness.
And because humans mostly look at vertical surfaces like walls, these should be
lighted first, and the ceiling next. Floors
should be lighted last—as humans rare-
Lighting Design for Health and Sustainability
INSIGHT
Susan T. Morgan, AIA, an
architect at MSR, described
how her firm uses early
analysis tools to inform its
understanding of a project’s
lighting potential and support
its collaborations with lighting designers:
“It is now standard practice on
our projects that we do a Sefaira
daylight modeling study as we’re
looking at preliminary massing
to help us understand orientation, building massing, and
geometry, and really maximizing
the floor plate for daylight within
the building. It’s been about a
year-and-a-half since we put that
into practice, and for us it has
made a huge difference in us
meeting our future and broader
project goals from an energy
standpoint.
“I think both on an individual
and a team level, it’s increased
our literacy, and on the other
hand it’s given us both tools
and vocabulary to educate our
clients about the effects that
these early decisions have. And
in fact, in many ways … it’s
freed them up from a long-term
commitment to electric lighting
and the idea that … these spaces can be broadly daylit for the
most part versus being broadly
electric[ally] lit. And that really is
a change in practice over the last
few decades.
“We usually have completed that
before we sit down with a lighting designer because oftentimes
we don’t bring them in until
we’ve already done a little bit
of a massing study and already
started to understand the general footprint of the building on
the site. But this becomes a tool
for our dialogue about what decisions we’ve made to date and
then what decisions lie ahead of
us so that we can talk together
about using the attributes of the
site to really maximize daylighting on the project.”
11
BuildingGreen Spotlight Report
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 involuntarily back and forth between peripheral distractions 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 incorporates 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.
• Accent lighting, sometimes referred to
as decorative lighting, is used to highlight points of interest in a space, like
an artwork or architectural feature.
• Task lighting provides illumination
for the specific tasks that occupants
perform in a space. Table and floor
lamps, desk lamps, and bathroom
vanity lighting are examples of task
lighting.
Photo: Andrea Calo
Harris explained how great lighting design could even go beyond creating comfort to cause delight. “Often there are
things that can happen with light that
help create a sense of wonder and awe
in certain ways,” he said. He added that,
though this isn’t necessarily the primary
goal, it is always very pleasant and appealing when the lighting, having been
carefully crafted, adds a human touch to
the architecture.
Lighting Design for Health and Sustainability
When designing the Austin
Central Library, by Lake|Flato
Architects, the project team
focused on the concept of
quality of light and set a goal
of making the project one of
the best daylit buildings in the
world.
12
BuildingGreen Spotlight Report
10. Reduce ambient, provide
task
One common strategy for achieving greater efficiency is to provide a reduced level
of ambient light in a space, and then provide users in that space the ability to focus higher levels of light on areas where
tasks are being performed. An example
would be individual task lamps on desks
in an open office space.
Lighting the walls and ceiling of a space
to produce a lower ambient light level
can also contribute to visual pleasure by
making a space look alive and balanced.
It also makes the space more flexible because the light is less tied to a certain set
of tasks.
11. Leverage technology to
protect health and increase
comfort
Light sources that provide a wider spectrum of light promote comfort because
they increase the occupant’s ability to
see objects in true color, the way they’re
meant to be seen. One reason daylight is
such a pleasant light source is that it provides the full spectrum of light, unlike
most electric light sources (like incandescent and fluorescent lamps), which only
provide portions of the spectrum.
However, LED technology has now advanced to the point where high quality
LEDs are able to provide the full spectrum of light, or close to it. Additionally,
it’s now possible to produce LEDs that
give the occupant the ability to control
the color temperature of the light source,
as well as the spectral distribution.
This is important because it allows occupants to tune the electric lighting in their
space, depending on the time of day, to
create optimal conditions for circadian
stimulus. For example, during the day,
electric lights can be tuned to a cooler,
neutral color temperature like 4,000 degrees Kelvin (4,000K), and in the evening
they can be tuned to a warmer temperature like 2,700K. (The lower the color temperature of the light, the closer it is to the
red end of the visible spectrum and the
“warmer” the light feels.) This creates a
more comfortable visual environment
and protects the occupant from excessive levels of cool, blue light, which, as
discussed earlier, can have a negative impact on the sleep cycle.
12. Specify high-quality LEDs
Because of these advanced capabilities,
LEDs have become the default source for
electric lighting in almost every application—valued as much for their ability to
create comfortable, pleasing light conditions as for their energy efficiency. (See
Innovative LED Lighting from LightFair
2018 to read about some of the most cutting-edge products in the field.)
However, manufacturing of LEDs is inconsistent, and not all LED products are
created equal. Just because a light source
Image: Phrood. License: Public domain.
Different color temperatures are used to create environments with different effects. Warmer
colors (lower temperatures) are used to create relaxing environments while cooler colors (higher 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.”
Lighting Design for Health and Sustainability
INSIGHT
Bob Harris, FAIA, principal
at Lake|Flato Architects,
described how a goal to maximize the quality of daylight at
the Austin Civic Library was
achieved and the impact it
had on the users:
“We really thought this goal
would be a worthy goal for
ourselves—to help create a
sense of how we want to shape
the architecture and the whole
approach to it. We worked
with lighting designers and
natural daylighting experts and
engineers and others to help
reinforce those goals from the
outset. We were able to do a lot
of that visioning and goal setting
upfront, and then put in the time
and attention that was necessary
to creating the right architectural
responses to the lighting. And
to bring both the natural and
artificial lighting to the table to
inform the building form, the
footprint, everything about the
way the program laid out on the
site, and to help shape the right
experience for the users.
“It really was our central
departure point for all those
decisions—the idea of quality
of light. It opened up this last
year and has been overrun with
citizens and people enjoying the
library in new ways that they'd
never had access to, at least in
Austin, or I’d say probably in the
state.”
He explained that, although
libraries are often thought of as
quiet, private, darker spaces, the
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 social meeting grounds for people
to come together around books
but also around education and
collaboration, and for meeting their neighbors and being
together—a place that I think
maybe libraries haven’t always
been in the past.”
13
BuildingGreen Spotlight Report
is an LED doesn’t automatically mean it’s
a good light source. In short, the quality
of an LED product depends on the supplier and the quality controls and root
technologies that supplier uses. There are
several different factors that are used to
determine the quality of a light source.
It can quickly get complicated, so having
a lighting specialist on the team to help
navigate the complexities is important.
13. Reduce power, time,
or both
When pursuing lighting energy-performance goals, it can be useful to think in
terms of the equation: energy = power ×
time. The power variable has to do with
the efficacy of the design (see definitions
of efficacy below), and the time variable
has to do with how long the light sources
are on.
Levitt explains, “If you can reduce either
power or time, you’re going to reduce energy. If you can reduce both, you’re going
to reduce a lot of energy. It’s also really interesting to note that if you can reduce either one a lot, then the other one matters
a whole lot less. So if you can reduce your
time, so that you only have lights on for
a half hour a day, then how much power
those use is much less important.”
The following five scales of efficacy—
which each affect the “power” variable of
the equation—can serve as a guide to help
project teams discuss and understand the
various ways different lighting products
and strategies impact the efficacy of the
overall lighting design:
• Lamp efficacy refers to the amount
of light a lamp supplies for a given
amount of electricity. It is measured in
lumens per watt, or LPW.
• Fixture or luminaire efficacy refers
to how efficiently a luminaire directs
the light offered by the lamp. For example, if the lamp offers a thousand
lumens, how well does the luminaire
act to direct those thousand lumens in
a way that’s useful? A luminaire with
black inner surfaces, which would
absorb a large portion of the lumens
offered by the lamp, would not be efficacious.
• Layout efficacy refers to how well the
fixtures in a space are located to properly illuminate surfaces and tasks.
• Room efficacy refers to how well the
characteristics of a space enhance the
lighting.
• Task efficacy refers to how well the illumination supports the task at hand.
Ideally, only the surfaces that need to
be illuminated for occupants to perform their tasks would be illuminated.
14. Provide controls
In addition to optimizing the efficacy of
the architectural space and specifying
high-performance light sources, project
teams can use controls to further reduce
energy use. In fact, some lighting designers argue that the only way to get a lighting system to save energy, regardless of
how efficient the light sources are, is to
combine them with proper controls.
Referring back to the “energy = power
× time” equation, the purpose of using
controls is to reduce the “time“ variable
as much as possible. In short, the lights
should either be dimmed or turned off
whenever possible.
Common types of controls used to reduce
lighting energy use include:
• photo sensors, which dim or turn
lights on or off in response to the
amount of daylight in a space
INSIGHT
Susan T. Morgan, AIA, an
architect at MSR, described
her experience working with
a lighting designer on a 700seat multi-purpose auditorium for a library:
“This is the kind of space where
generally we have to control
daylight because … it’s theater performances, it’s music
performances—you don’t think
of having to bring daylight into a
space like that. But because the
client wants to use it for other
events, we started having very
early conversations in pre-design
about ‘Is there a way to bring
daylight in?’
“And having a working charrette
[with the lighting designer], we
actually talked through the differences. Typically as architects
we look at things from a form
basis—so, ‘What if we put the
windows on the side, what if
we put the windows on the top,
what is the shape, what is the
aspect?’ And to bring Brennan
[the lighting designer] into that
conversation allowed us to really
talk through not just, ‘What if
we do it on this side?’ but what
are some of the outcomes … in
terms of quality of light—the color, and the hue, and the intensity? How easy or how difficult is it
for us to manage daylighting on
each of these facades?
“So that allowed us … at a kind
of deeper level to really kind of
think through possibilities, but
to also understand the outcomes
a little more fully than you typically would during a pre-design
phase, so it helps establish goals
in a more specific and deliberate
way than sometimes you would
be able to.”
• occupancy sensors, which dim or
turn lights on or off in response to the
presence of occupants in a space
• time clocks, which dim or turn lights
on or off based on an automated schedule that is programmed according
Lighting Design for Health and Sustainability
14
BuildingGreen Spotlight Report
to occupancy patterns or the daily
sunrise and sunset times for the project’s geographical location
• 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 required by code depending on project location, should ideally be designed and
calibrated so that they are as seamless
as possible. For example, when using occupancy sensors, project teams should
specify dual-technology sensors that detect both ultrasonic and infrared signals.
These operate with fewer issues because
they require the absence of both types
of signals before dimming or turning off
lights, but require the presence of only
one type to turn lights on. It’s also important to give occupants the ability to easily
adjust or override the sensors remotely if
they need to.
Whether or not it makes sense to integrate
lighting controls into the central building
management system will depend on a variety of factors, such as project scale and
typology, budget, users, and the facility
Photo: Brandon Stengel
staff’s familiarity and comfort with the
system. For example, in projects with a
specific and fixed set of uses, and a regular group of users and schedules, centralized control can streamline efficiency
by reducing the number of people who
need to engage with the system. However, in public buildings, with a varying
set of uses and many different users occupying the building at irregular times, a
more simplified, intuitive, decentralized
system of controls is needed to provide
for occupant comfort.
The Louisville Free Public
Library South Central Regional Library, designed by MSR,
provides an example of how
daylighting and artificial lighting
can be balanced to create a
quality environment.
It can prove valuable to have the lighting
system communicate with the building’s
energy management system to produce
detailed reports on the use and energy
consumption of the lights. Facility management staff can use this feedback to
monitor whether the lighting system is
operating correctly or to locate the issue
if something’s not working as expected.
Lighting Design for Health and Sustainability
15
BuildingGreen Spotlight Report
SIDEBAR: LED BASICS
What Is an LED?
Energy efficiency
• LED (light emitting diode) lighting, or solid-state
lighting (SSL), uses semiconductors (LED chips) to
produce light as current flows across it. This produces
energy, as photons of light, and also releases some heat.
Using different semiconductor materials or engineering
produces different colors of light. White light can also be
created by using combinations of red, green, and blue
LEDs.
• LED lamps (sometimes called bulbs) are made up of
the following components: an LED chip or chips, a heat
management system (heat sink), electronics, and optics.
• LED luminaires (light fixtures) include the LED lamp
and components required to connect the lamp to the
power supply, protect the lamp, and distribute the light.
Optics
• 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.
• Primary optics cover the LED chip to help improve light
output. Phosphors that are critical for changing “blue”
light to warmer reds and yellows are often added to
these optics.
• Secondary optics typically adjust the beam angle or
create a more diffuse light.
Drivers and dimmers
• LEDs run on direct current (DC) and usually require a
driver, or power supply, to convert alternating current
(AC) from the utility to DC. Dimmers and building automation can also be integrated into the luminaire. In an
LED replacement lamp, the driver and other electronics
are contained in the base of the lamp.
• Other LED luminaires use external drivers, either
constant-current drivers that pair one light per driver,
or constant-voltage drivers that connect to multiple
lights connected in parallel. Drivers are critical to the
efficacy and overall performance of an LED luminaire.
• Energy efficiency in lighting is measured in the amount
of light produced (lumens) per watt of energy
consumed, or lumens per watt (lpw).
• Luminous efficacy (sometimes called source efficacy
or even LED efficacy) is the efficacy of just the LED chip
before the optics, driver, and other electronics are
added. Addition of the driver and other components
lower the efficacy of the luminaire significantly. Manufacturers often tout the amazing efficacy of their chips,
which can be confusing. Cree, for example, surpassed
300 lpw for one of its chips in 2014, but luminaires
rarely reach 110 lpw.
• Luminaire efficacy is a measure of the efficacy of the
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
color rendering index generally have lower efficacies.
Color and Quality
• LED color and quality are measured by the color
rendering index (CRI) and the correlated color
temperature (CCT).
• CRI is a measure of how accurately a light source
renders the colors of an object compared to a reference
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.
• CCT (measured in Kelvins) is based on the colors
given off by an ideal metal heated up to the point of
glowing. Most lighting falls in the 2,000K (orange-yellow
candlelight) to 6,500K (blue midday sunlight) range. In
general terms, 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.”
Light quality can vary between brands, and there are
no definitive color temperature cutoffs, but 3,200K to
4,500K are sometimes labeled neutral or cool white,
and those above 4,500K are sometimes called cool
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.
Lighting Design for Health and Sustainability
16
BuildingGreen Spotlight Report
15. Integrate interior and
exterior lighting
17. Conduct post-occupancy
evaluations
Especially on public projects, exterior
lighting providing nighttime visibility is
important for way-finding, security, and
safety, but if it is not carefully designed or
if too much light is provided, it can cause
glare, light trespass, and habitat disruption.
It’s always a good practice to visit projects
after occupancy to verify that all systems
are operating as designed and to address
any issues that occupants may have. This
is especially important when it comes to
lighting systems, as they have a significant impact on usability and comfort.
Although often exterior lighting is considered more as an afterthought, it can have
a significant impact on the experience
of the building. Architects should work
together with the lighting designer, the
landscape architect, and engineers to develop a holistic strategy in which interior
and exterior lighting interact seamlessly
and connect indoor and outdoor space.
On larger buildings with more complex
light systems, it’s important to go back
after the building has been occupied for
a few months and fine-tune the programming to match the actual use of the building as precisely as possible.
16. Commission the system
Once construction is complete, it’s crucial to commission the lighting system to
ensure that all the various components
have been installed and programmed
correctly. The more complex the lighting
design—projects with multiple sophisticated control schemes—the more important commissioning becomes.
The commissioning process can often
uncover small issues that seem minor
but can result in significant negative impacts on efficiency and occupant health
and comfort. For example, an occupancy
sensor may be installed too close to an air
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.
Some of the most common complaints related to lighting gathered during post-occupancy evaluations have to do with occupancy sensors. If the sensors are not
operating correctly, occupants will often
get frustrated and override them. It’s important then to resolve any issues there
may be with the sensors to make sure that
they continue to operate and contribute
toward energy savings.
It is also critical to work with the building management staff to make sure they
understand how the controls and various
features of the lighting system work. The
more informed they are about how the
system works, the more likely they are to
engage with it to make sure it’s operating
at peak performance and that maximum
energy savings are being captured.
Lighting Design for Health and Sustainability
INSIGHT
Brennan Schumacher, lighting
designer and senior associate
at Mazzetti + GBA, gave an example of how educating the
building manager about how
to engage with the lighting
control system led to further
energy savings:
“We did the J. Craig Venter Institute a few years back.… We had
all the dim levels topped out at
75% so none of the lights could
come to full brightness, and we
told the building manager, if you
take that down 1% a day until
you find people starting to say it
doesn’t feel like we have enough
light, and then ratchet it back up
3 or 4 points—they feel like they
have great light, and you just
saved 12% more energy.
“The programming side—I can’t
stress it enough—it’s really,
really important, and for better
or worse, it often comes down
to the individual [who’s] actually
onsite. … So we try to be onsite
when the programming is happening, and I find that that adds
a lot of value. We can answer all
their questions right there on
the spot, they hear more about
our design intent, and I think
they care more when the person
[who] designed it is working with
them rather than just sending
them spreadsheets from 600
miles away.”
17
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
a BuildingGreen Premium member, you
can get continuing education credits by
successfully completing this quiz on our
website.
Learning Objectives
For BuildingGreen to automatically report
your CEUs, you will need to add your AIA
and/or GBCI identification info to your
profile, at www.buildinggreen.com/user.
Description
What do we mean when we say sustainable lighting? In this course BuildingGreen takes a closer look at lighting as
an essential element in quality environments that support health and wellness
while reducing energy use.
The functionality of a building is largely
dependent on the quality of its lighting,
which is often treated as a secondary concern, taking a back seat to form-making.
Lighting design can have either positive
or negative effects on people, especially
in the spaces where many people spend
a lot of time. In order to safely and comfortably perform their tasks, occupants
need lighting that provides adequate visibility 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
Upon completion of this course, participants will be able to:
1. Describe how high-quality lighting
design dovetails with sustainability
by improving energy efficiency and
supporting occupant health and
well-being.
®
2. Explain the sustainability benefits
of daylighting, including increased
energy efficiency and wellness,
along with the drawbacks of poor
daylighting design—such as excessive glare and solar heat gain,
which can reduce energy efficiency
and cause occupant discomfort.
3. Define basic lighting terms, such as
“play of brilliance,” “spatial daylight
autonomy,” and “color rendering
index,” along with the relevance of
such lighting terms to improved efficiency and occupant wellness.
4. Understand the expanding role of
high-quality LEDs in sustainable
lighting design, and demonstrate
proficiency with the vocabulary of
LEDs relating to efficacy and light
quality.
Lighting Design for Health and Sustainability
18
QUIZ QUESTIONS
1. I n order to safely and comfortably perform their
tasks, occupants need lighting that provides
adequate visibility without causing ____.




a.
b.
c.
d.
Thermal mirages
Faintness
Discomfort or distraction
Tint and texture
2. High-quality ____, beyond providing basic comfort,
can protect and promote health.




a.
b.
c.
d.
Lighting
Air
Stilts
Dressings
3. L ike acoustic design, ____ can have either positive
or negative effects on people, especially in the
spaces where many people spend a lot of time,
like schools and offices.




a.
b.
c.
d.
Aperture
Lighting design
Window treatments
Oranges
4. S tudies have shown that in healthcare settings,
poor lighting conditions can hinder the way people
work, learn, and heal by causing ____.
(Select all that apply)




a.
b.
c.
d.
Distraction
Discomfort
Fatigue
All of the above
a.
b.
c.
d.




a.
b.
c.
d.
Waterways
The air
Outdoor shoes
Pets
7. According to the Energy Information Administration,
in 2010, lighting in U.S. commercial buildings
required ____ kWh of electricity—about 22% of total
commercial building electricity use in the nation.




a.
b.
c.
d.
156 trillion
297 billion
758 million
124 million
8. Play of brilliance refers to lighting that sparkles,
shimmers, or shines, such as chandelier or sunlight
reflecting on ____ .




a.
b.
c.
d.
Water
Windows
Walls
Wellies
9. The three standard layers of light that creates an
interesting, comfortable, and flexible environment
are task, accent, and ambient lighting.
 a. True
 b. False
5. P
roject teams should avoid ____ by not overlighting, 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, and communities.




6. Some chemicals of concern in lighting products
are compact fluorescent lights, which contain
highly toxic mercury and LEDs that contain copper
which can create an environmental hazard if it
accumulates in ____.
Sound barriers
Integrated complexities
Tight hamstrings
Light pollution
10. Common types of controls used to reduce lighting
energy use include: (Select all that apply)





a.
b.
c.
d.
e.
Photo sensors
Occupancy sensors
Time clocks
Demand-response system
All of the above
TAKE THE OFFICIAL QUIZ
www.buildinggreen.com/spotlight/lighting