Russell Leslie, Aaron Smith, Leora Radetsky, Mariana Figueiro, and

74 Pages·2011·7.54 MB·English

Russell Leslie, Aaron Smith, Leora Radetsky,
Mariana Figueiro, and Lisa Yue

Patterns to
Daylight Schools
for People
and Sustainability
Russell Leslie, Aaron Smith, Leora Radetsky,
Mariana Figueiro, and Lisa Yue
Copyright © 2010 Rensselaer Polytechnic Institute. All rights reserved.
Neither the entire publication nor any of the information contained herein may
be duplicated or excerpted in any way in any other publication, database, or oth-
er medium and may not be reproduced without the express written permission of
Rensselaer Polytechnic Institute. Making copies of all or part of this publication
for any purpose other than for undistributed personal use is a violation of United
States copyright law.
Acknowledgments
T
he authors wish to thank the United States Special thanks to Dennis Guyon for graphic design
Green Building Council (USGBC) for their and to members of the Lighting Research Center for
prescient recognition of the importance of their substantial contributions to this publication:
studying the impact of daylighting in schools and for Jennifer Brons, Rosa Capó, Christine Kingery, Anna
their generous sponsorship of the research and design Lok, Sara Nonaka, Barbara Plitnick, Mark Rea, and
leading to this book. Support for the work presented Rinara Reh.
here was also given by the Trans-NIH Genes, Environ-
ment and Health Initiative Grant U01 DA023822.
iv
Patterns to Daylight Schools for People and Sustainability
Table of Contents
Acknowledgments ........................................................................................................iv
Preface ............................................................................................................................2
Introduction ...................................................................................................................2
Background ....................................................................................................................3
How to Use This Book ..................................................................................................4
Goals and Metrics for Designing Daylighting for Schools ............................................5
Average Illuminance .........................................................................................6
Coverage ...........................................................................................................6
Diffuse Daylight ................................................................................................7
Daylight Autonomy ..........................................................................................7
Circadian Stimulus ...........................................................................................8
Glazing Area .....................................................................................................8
View ..................................................................................................................9
Solar Heat Gain ................................................................................................9
Ten Design Principles for Daylighting Schools ...........................................................10
Space Planning ............................................................................................................10
Turn Off the Lights ......................................................................................................11
Beyond Architectural Design ......................................................................................11
Electric Light ..................................................................................................11
Evening Light ................................................................................................12
Exposure Zones ...............................................................................................12
Material Choices .............................................................................................12
Schedule ..........................................................................................................12
Limitations ...................................................................................................................12
Electric Light ..................................................................................................12
Climate ...........................................................................................................12
Glazing ............................................................................................................12
Illuminance .....................................................................................................13
Circadian Stimulation ....................................................................................13
Refl ectance ......................................................................................................13
Shading Systems .............................................................................................13
Space Size .......................................................................................................13
Patterns for Daylighting Schools .................................................................................15
Classrooms ......................................................................................................16
Corridors .........................................................................................................48
Gymnasiums ....................................................................................................56
References ....................................................................................................................66
Additional Resources ...................................................................................................67
1
Preface
S
ince the early 90’s, the Lighting Research Cen- (cid:129) The designs and technical analyses are distilled
ter (LRC) has used pattern books as a means to to visual presentations for architects and school
accelerate the implementation of sustainable administrators.
lighting practice. These pattern books offer model de- (cid:129) A “daylighting dashboard” is introduced, a graphic
signs that can be adapted to your particular building and method to quickly compare the patterns. These
style. To have a large impact, lighting patterns should: comparisons include indicators of cost, comfort, the
(cid:129) Illustrate lighting solutions adaptable to many styles visual environment, and energy use.
and applicable to common, rather than monumen- (cid:129) Partnering with the U.S. Green Building Council
tal or unique buildings (USGBC), we offer wide electronic distribution to
(cid:129) Be clearly communicated in a format familiar to the reach many daylighting decision makers.
intended audience Beyond direct application of these patterns, we
(cid:129) Include pattern performance in a format that allows hope that this approach encourages objective evalua-
comparison among pattern alternatives tion of daylight alternatives for all school buildings in
(cid:129) Be widely distributed. all climates. Model your evaluations after the analyses
Here we continue this legacy of pattern books, contained on the following pages. Monitor the rapidly
merging daylighting design with a light and health per- developing research in light and health to make student
spective, two key research areas at the LRC. Patterns to well-being a vested component of the analysis. Save en-
Daylight Schools for People and Sustainability follows the ergy while enjoying the beauty of daylight in schools.
four objectives above:
Russell P. Leslie, AIA FIES
(cid:129) Conceptual daylight approaches are offered for the
three most common spaces in schools: classrooms,
corridors, and gymnasiums.
Introduction
D
aylighting is the design of buildings to use when the school’s site, confi guration, and fenestration are
light from the sun. Done properly, daylight- formulated. Therefore, this book emphasizes schematic
ing in schools creates interesting, dynamic in- patterns to daylight typical classrooms, corridors, and gym-
teriors supportive of human health and activities while nasiums. Furthermore, exciting new science is demonstrat-
reducing energy demand. Done improperly, daylighting ing that lighting has a signifi cant impact, not just on our
impedes vision, causes discomfort, and demands exces- visual system but, on our health and well-being. This book
sive energy. balances well-known daylight design approaches with new
The most critical decisions for a well daylit building guidelines addressing these photobiological benefi ts of
come during the conceptual phase of architectural design, daylighting schools.
2
Patterns to Daylight Schools for People and Sustainability
Background
T
here are many excellent guides for daylight de- to get up early for school the following morning.
sign (see page 67). These guides often cite the The hypothesis posed by LRC researchers was that
benefi ts of daylight for saving energy, reducing the students who were not exposed to morning light
peak electric load, allowing continued operation dur- or daylight that would stimulate the circadian system
ing power outages, and using view to connect people would experience a more pronounced delayed circadian
to their external environment. Further, frequent claims phase, which would result in later bedtimes, and possi-
tout benefi ts of daylight for student productivity and bly chronic sleep deprivation, stress or mood disorders.
health, but there has not been a well established basis If the lighted environment in schools can promote cir-
for these claims.1,2 New science, however, has now estab- cadian entrainment by delivering light that will shift
lished a physiological basis that may explain these claims. the biological clock to an earlier time, students will fall
In response to the earth’s 24-hour cycle, all species asleep earlier at night and sleep deprivation will be re-
have evolved daily biological or circadian rhythms (for duced. In turn, students should feel better and perform
example, sleep/wake behavior) that repeat approxi- better in school.
mately every 24 hours. Circadian rhythms are generated Having enough light in the classroom to read and
and regulated by a biological clock located in the hu- study does not guarantee that there is suffi cient light to
man brain. In the absence of external cues, human cir- stimulate our biological clocks. This is because the hu-
cadian rhythms will run with an average period of 24.2 man visual system responds differently to light than the
hours. People are synchronized, or entrained, to the 24- human circadian system, which is much more sensitive
hr solar day most strongly by the Earth’s natural light/ to short-wavelength (blue) light and needs more light
dark cycle.3 Morning light will advance the biological to be activated than the visual system.9-12 Most schools
clock, resulting in earlier bedtimes, while evening light typically do not provide adequate electric light or day-
will delay it, resulting in later bedtimes.4 Since humans light to fully stimulate the circadian system. However,
have a circadian clock that is slightly longer than 24 if designers provide suffi cient daylight, which contains
hours, we need a daily morning light dose to advance ample, short-wavelength (blue) light, in classrooms,
our biological clock and, therefore, keep us entrained school buildings will be able to provide more circadian
with the solar day. stimulation and therefore, better support for circadian
In 2008, the USGBC awarded the LRC a grant to entrainment.
study the impact of daylight design on students’ well- The LRC’s fi eld studies found that insuffi cient ex-
being and performance in K-12 schools. Today’s middle posure to daily morning light contributes to teenagers
and high schools have rigid schedules requiring teenag- not getting enough sleep due to later bedtimes. Eleven
ers to be at school very early in the morning. These stu- eighth grade students, who wore special glasses that
dents are likely to miss the morning light because they fi ltered out short-wavelength (blue) morning light, ex-
often travel to school before the sun is up or as it is just perienced a 30-minute delay in their dim light mela-
rising; therefore, they may miss the light that promotes tonin onset (DLMO) by the end of the fi ve-day study.
the entrainment of their biological clock to the external Melatonin is a hormone produced at night and under
environment. Lack of entrainment between light and conditions of darkness. The onset of melatonin typi-
dark and the biological clock may lead to sleep depriva- cally occurs about two hours prior to falling asleep. A
tion, as well as symptoms of stress, mood disorders, and later DLMO is generally associated with a later bed-
perhaps immune system defi ciencies.5-8 In adolescents, time. Principal investigator Dr. Mariana Figueiro
sleep deprivation has been linked to one’s inability to concluded, “These morning-light-deprived teenagers
fall asleep at appropriate evening hours and one’s need are going to bed later, getting less sleep and possibly
3
under-performing on standardized tests.” students should receive the light that activates the cir-
Furthermore, exposure to early evening daylight in cadian system in the early morning and avoid that same
the springtime was found to have a similar effect on the light in the early evening.13
biological clock. In the springtime, later sunset and ex- How then, should architects employ these fi ndings
tended daylight exposure in the evening can also delay in the design of schools? This book translates current
bedtimes for teenagers. This research shows that expo- light and health research fi ndings to recommendations
sure to short-wavelength (blue) light in the evening for school design. The patterns on the following pages
has just as much effect on the body as removing early merge these recommendations with well-established
morning light; both delayed sleep onset in students. daylighting design principles to assist architects seeking
For a more regular sleep pattern and earlier bedtimes, to create healthy and sustainable schools.
How to Use This Book
A
rchitects should use this book to identify
potential approaches, or “patterns,” to day-
light classrooms, gymnasiums, and corridors
in schools. Similar to traditional architectural pat-
tern books, this book gives model designs that can be
adapted in confi guration and style to a particular school
project. To aid in the selection of patterns that meet
the architect’s design objectives, this book identifi es
positive attributes and fl ags potential shortcomings of
each pattern, summarized in a color-coded diagram, a
“daylighting dashboard,” which represents eight goals
for good daylighting design.
The daylighting dashboard, shown on the right, is
divided into eight segments, each representing one of
The daylighting dashboard.
the daylighting goals described on pages 6-9. Each goal
includes an associated metric. The daylighting dash- infl uences the building design. The daylighting dash-
board summarizes a pattern’s performance. board described in this book provides an overview of
A red rating is a warning that the goal is unlikely to the performance trade-offs of each pattern.
be met with the pattern; yellow indicates caution, for Consider this book as a conceptual tool. This guide
example careful evaluation or modifi cation of the pat- allows comparison of the likely merits of generic daylight-
tern is necessary to fully meet the goal; green indicates ing approaches in schools. For a specifi c project, several
that the designer is well on the way to fully meeting that candidate patterns should be identifi ed for each room.
goal. The eight goals are evaluated with the following Then, during schematic design, a site-specifi c analysis
metrics: average illuminance, coverage, diffuse daylight, should be conducted to fi ne tune the performance rat-
daylight autonomy, circadian stimulus potential, glazing ings. In order to further improve the performance of the
area, view, and solar heat gain. schematic design, ten principles for daylighting schools,
Architects may weigh the importance of the eight listed on p. 10, should be considered. The References and
goals differently for different projects. Sometimes cost Additional Resources sections offer further information
is the driver; other times view or energy savings most that will aid in the school’s daylighting design.
4
Patterns to Daylight Schools for People and Sustainability
Goals and Metrics for Designing Daylighting for Schools
D
aylighting design, like most design, must pri- conditions for the Albany, NY area. A day during each
oritize sometimes confl icting design goals. of the four seasons was chosen: March 21, June 21, Sep-
The patterns contained herein provide con- tember 21, and December 21 were each evaluated at
ceptual feedback on how well each pattern would meet 9:00 a.m., 12:00 p.m., and 3:00 p.m.
a particular design goal. Thus, eight simple goals are The building energy use analysis tool, eQUEST,‡
evaluated for each design. Unlike other daylighting was used to evaluate the monthly and yearly solar heat
guides, these patterns also include the pattern’s poten- gain for each pattern. Since the program is not able to
tial to stimulate the circadian system. It is up to the separate clear and cloudy conditions, the daylighting
designer to weigh the relative importance of each goal dashboard reports a composite yearly average solar heat
and then to select candidate patterns for further analy- gain for clear and cloudy skies. Monthly averages for
sis during design development. Eight goals that should March, June, September, and December can be found
be at the forefront of any good daylighting design and in each pattern’s data table.
the metrics used for the daylighting dashboard are ex- Each pattern’s performance during the 12 represen-
plained on the pages 6-9. tative times was simulated under both clear and cloudy
Each goal on the daylighting dashboard includes a conditions. The data from each grid were used as the
metric for evaluating the pattern. The evaluation used input for evaluating the illuminance, coverage, diffuse
AGi32† to analyze each pattern. Illuminance values in daylight, daylight autonomy, and circadian stimulus.
footcandles (fc) were calculated at each point of a hori- The evaluation results are shown with each pattern
zontal grid located on the work plane 2.5 feet above the beginning on page 14.
fl oor. Each pattern was evaluated under typical daylight
† - AGi32 version 2.13 lighting software, Lighting Ana- ‡ - eQUEST version 3.64 building energy simula-
lysts, Inc., Littleton, Colorado. Download available at tion tool. eQUEST is a registered trademark of James
www.agi32.com J. Hirsch & Associates. Freeware is available at
doe2.com/equest
5
Average Illuminance
Goal daylight is usually suffi cient for all tasks typical of the
Provide suffi cient daylight to space. Red indicates that there will often be insuffi cient
perform tasks. daylight to perform tasks of small size and low contrast.
Yellow indicates that daylight levels are often below
Average illuminance on the
the target illuminance or that there is excessive illumi-
horizontal work plane is an in-
nance, which may produce uncomfortable glare.
dicator of daylighting availabil-
ity for performing visual tasks.
Approach
Illuminance signifi cantly below Illuminating Engineer-
The target illuminance for suffi cient daylight was guid-
ing Society (IES) recommended levels makes seeing
ed by the IES recommended values.14 The relative vi-
diffi cult without supplementary electric light. Excessive
sual performance (RVP) model was used to select a low
illuminance may cause glare, fade materials, and could
illuminance criterion based on the dominant tasks for
be an indicator that there is more glazing than necessary
each pattern.15 The 500 fc high illuminance criterion
in the space.
was based on the LEED 2009 IEQ credit 8.1.16
Metric
Green indicates that the average illuminance from
Classroom Corridor Gymnasium
Green 30-500 fc 10-500 fc 30-500 fc
Yellow 10-29 or greater than 500 fc 2-9 or greater than 500 fc 10-29 or greater than 500 fc
Red Below 10 fc Below 2 fc Below 10 fc
Coverage
Goal Metric
Avoid under-lit areas by distributing Green indicates that the entire space is above the low
ambient light throughout the space. illuminance criterion. Yellow indicates that most of the
space is above the low illuminance criterion. Red indi-
Coverage is the percentage of
cates that a signifi cant portion of the space is under-lit.
the work plane that is above the
low illuminance criterion. High
coverage is an indicator that Approach
most parts of the room are receiving adequate amounts The percentage of workplane calculation points was
of daylight to perform visual tasks. Low coverage indi- calculated above the low illuminance criteria, 10 fc for
cates under-lit areas from daylight. A space with under- classrooms and gymnasiums, and 2 fc for corridors, was
lit areas juxtaposed with well-lit areas may contribute to tabulated.
visual discomfort.
Classroom Corridor Gymnasium
Green 100% above 10 fc 100% above 2 fc 100% above 10 fc
Yellow 80-99% above 10 fc 80-99% above 2 fc 80-99% above 10 fc
Red Less than 80% above 10 fc Less than 80% above 2 fc Less than 80% above 10 fc
6