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Daylighting study of a LEED platinum laboratory building: a post-occupancy evaluation comparing performance in use to design intent

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Daylighting study of a LEED platinum laboratory building: a post-occupancy evaluation comparing performance in use to design intent

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DAYLIGHTING STUDY OF A LEED PLATINUM LABORATORY BUILDING:

A Post-Occupancy Evaluation Comparing Performance in Use to Design Intent

By

Kelly L. Burkhart

Presented to the
FACULTY OF THE
SCHOOL OF ARCHITECTURE
UNIVERSITY OF SOUTHERN CALIFORNIA
In partial fulfillment of the
Requirements of degree
MASTER OF BUILDING SCIENCE

MAY 2016

1

COMMITTEE

Kyle Konis, AIA, Ph.D.
Assistant Professor
USC School of Architecture
kkonis@usc.edu

Joon-Ho Choi, Ph.D.
Assistant Professor
USC School of Architecture
joonhoch@usc.edu
(213) 740-4576

Karen Kensek
Assistant Professor
USC School of Architecture
kensek@usc.edu
(213) 740-2081

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ACKNOWLEDGEMENTS

I would like to thank the architect and engineers of the building for supporting this study and for providing
the information about its design. I would also like to thank the occupants and especially the managers of
the Jorgensen Lab for providing access to the facility and participating in the study. This thesis would not
have been possible without the cooperation and support of all those involved.

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ABSTRACT

Daylighting is a common goal for sustainability-focused projects looking to achieve energy efficiency and
occupant comfort and well-being. However, it is less common to evaluate the outcomes of these designs
once the building is constructed and occupied; there is currently no established feedback loop to inform
designers which strategies are most and least effective in meeting daylighting goals.

In 2010, a university laboratory building in Southern California underwent a major renovation, most
noticeable of which was a retrofit of the façade. One of the major goals of the renovation was to design
for maximum daylight utilization. The major strategies used for daylighting included the construction of
a highly-glazed curtainwall and placement of the laboratories and office spaces at the perimeter of the
building. The renovated building earned a LEED Platinum rating under LEED v2009.

In order to evaluate the daylighting design outcomes in this laboratory building a methodology was
employed that consisted of two major parts: physical data collection in laboratories and office spaces and
occupant surveys. The data collection consisted of observation of interior shade positioning and usage,
and measurements off illuminance, glare, and spectral power distribution. The survey of building
occupants was completed in two ways. The first was through a repeated-measures survey which polled
occupants about their visual comfort at defined intervals over a two-week period by means of a smartphone
application. The second survey method was a traditional one-time survey which asked occupants about
their satisfaction with daylight, glare, and views in their workspaces. Through these methods, five research
questions were evaluated in three categories:

1) Façade: Does the achieved visible light transmittance (VLT) of the façade and components in use
match what was intended by the designer?
2) Physical Light Properties:
a. Are the horizontal daylight illuminance levels intended by the designer being achieved?
b. Is there a high potential for glare discomfort?
c. Is the spectral power distribution from daylight sufficient for human health and well-being,
specifically in regards to melatonin suppression?
3) Human Comfort: What percentage of occupants are satisfied with daylight and views in their
workspaces?

The results found that the VLT of the façade is greatly reduced from the intended design due to high
occlusion by interior shades. The illuminance in the laboratories only met the intended design levels in
the morning hours. Glare (measured by daylight glare probability) was effectively mitigated in most of
the measured areas of the building. Despite reduced daylight penetration caused by interior shades,
spectral power distribution was sufficient for adequate melatonin suppression in most measured areas.
Occupant satisfaction with daylight was 79% in offices and 85% in laboratories, although a number of

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occupants also reported that daylight levels were low, but not low enough to cause discomfort. Occupant
satisfaction with views was only 25% in offices and 63% in laboratories, likely due to the high occlusion
of the façade by the interior shades.

Most of the results are a product of shades usage of lack thereof. The effectiveness of the building’s
daylighting design is heavily dependent upon an adaptive building. In the case, the ability of the building
to adapt to the daylight conditions is dependent upon the occupants to adjust interior shades and artificial
lighting. Optimal adjustment of the indoor environment by the occupants is not occurring, meaning that
the building is not meeting its full daylighting potential.

HYPOTHESIS

By comparing daylighting performance in use to design intent, it can be determined which strategies are
most effective and critical to achieving design goals.

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TABLE OF CONTENTS
ACKNOWLEDGEMENTS ..................................................................................................................... 2
ABSTRACT ............................................................................................................................................... 3
HYPOTHESIS........................................................................................................................................... 4
LIST OF FIGURES .................................................................................................................................. 7
LIST OF TABLES .................................................................................................................................. 12
1 INTRODUCTION............................................................................................................................... 13
1.1 The Importance of Studying Buildings .......................................................................................... 13
1.2 Important Terminology .................................................................................................................. 15
1.3 Study Boundaries ........................................................................................................................... 16
1.4 Scope of Work ................................................................................................................................ 17
1.5 Chapter Structure ............................................................................................................................ 17
2 BACKGROUND ................................................................................................................................. 18
2.1 The Push for Better Performing Buildings ..................................................................................... 18
2.2 Post-Occupancy Evaluation and Daylighting................................................................................. 19
2.3 Illuminance ..................................................................................................................................... 21
2.4 Glare ............................................................................................................................................... 24
2.5 Spectral Power Distribution ........................................................................................................... 25
2.6 Chapter Summary ........................................................................................................................... 27
3 JORGENSEN LABORATORY BACKGROUND .......................................................................... 28
3.1 Renovation Design Goals ............................................................................................................... 28
3.2 Daylighting Design Considerations & Strategies ........................................................................... 31
3.3 Chapter Summary ........................................................................................................................... 35
4 METHODOLOGY ............................................................................................................................. 36
4.1 Physical Data Collection ................................................................................................................ 37
4.2 Occupant Survey ............................................................................................................................ 43
4.3 Chapter Summary ........................................................................................................................... 44
5 RESULTS ............................................................................................................................................ 45
5.1 Laboratory Results ......................................................................................................................... 45
5.2 Office and O.M.G. Survey Results ................................................................................................ 64
5.3 Overall Occupant Survey ............................................................................................................... 71
5.4 Chapter Summary ........................................................................................................................... 75
6 DISCUSSION ...................................................................................................................................... 76
6.1 Laboratory Results Discussion ....................................................................................................... 76
6.2 Office & O.M.G. Survey Results Discussion ................................................................................. 80

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6.3 Overall Occupant Survey ............................................................................................................... 84
6.4 Chapter Summary ........................................................................................................................... 86
7 CONCLUSIONS ................................................................................................................................. 88
7.1 Façade Visible Light Transmittance .............................................................................................. 88
7.2 Lighting Physics ............................................................................................................................. 89
7.3 Human Comfort .............................................................................................................................. 91
7.4 Summary of Conclusions and Lessons Learned ............................................................................ 92
7.5 Study Limitations ........................................................................................................................... 93
7.6 Future Work ................................................................................................................................... 93
BIBLIOGRAPHY ................................................................................................................................... 95
APPENDIX .............................................................................................................................................. 97

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LIST OF FIGURES

Figure 1. Example of Spatial Daylight Autonomy (sDA). The numbers in the grid indicate the percentage
of hours during the analysis time period (which is 8 AM to 6 PM 365 days of the year) that the location
is receiving more than 300 lux of sunlight. The number below the grid indicates that 11.91% of the
analysis area exceeds the threshold of 300 lux for more than 50% of the hours. ................................... 23
Figure 2. Annual Sunlight Exposure (ASE). The numbers in the grid indicate the percentage of hours
during the analysis time period that the illuminance from the sun exceeded 1000 lux. The number below
the grid indicates that 27% of the analysis area is above the threshold of 250 hours above 100 lux. .... 24
Figure 3. Spectral response of vision and circadian systems. While our visual systems respond ideally to
wavelengths around 550 nm, our circadian systems respond best to blue light around 480 nm (American
Society for Photobiology 2010). ............................................................................................................... 26
Figure 4. (Left) Spectral power distribution of natural sunlight, peaking in the range of blue light around
480 nm. This results in 67% melatonin suppression. (Right) Spectral power distribution of fluorescent
light (mixed with natural sunlight) with dramatic peaks in the red, green, and blue ranges. This results in
42% melatonin suppression. (Please note that that y-axes are at slightly different scales). ................... 26
Figure 5. Jorgensen Lab in 2011 before renovations began. The façade consists of large concrete
overhangs. This view is of the rear of the building. (JFAK Architects 2015) ............................................. 28
Figure 6. Diagram of façade retrofit process, which included removing the large concrete overhangs on
the upper two floors, extending the top floor façade outward to encompass what was previously a
balcony, and replacing the patio and bridge entrance with a pavilion. (JFAK Architects 2015) .............. 30
Figure 7. Jorgensen Lab at the California Institute of Technology in 2012 after the renovation was
completed. This is a view of the rear/north façade. (JFAK Architects 2015) ........................................... 30
Figure 8. Example of view-preserving shades in use in the Jorgensen Lab. ............................................. 31
Figure 9. Before and after cross-sections and photos of the façade. Before the retrofit, large concrete
overhangs blocked sunlight and the view to outside. After the retrofit, the views are enhanced and
sunlight penetrates deep into the space. (JFAK Architects 2015) ............................................................ 32
Figure 10. LEED Daylighting credit verification measurements in foot candles. (Left) Northeast corner lab:
100% of the area meets required daylighting of >10 fc. (Right) South facing lab: only the back row of
measurements does not meet the >10 fc daylighting requirement. (Kessner 2015). ............................. 34
Figure 11. Study methodology flowchart. ................................................................................................ 36
Figure 12. Jorgensen Lab second floor. Of the 3 major labs (highlighted) the NE and S Labs were studied.
The SW Lab was no studied due to minimal glazing and no daylighting design intention. ..................... 37

8

Figure 13. Example photo of shade position documentation. Pictured here is the east façade in the NE
Lab on November 13 at 10 a.m. ................................................................................................................ 38
Figure 14. Illuminance meter. ................................................................................................................... 38
Figure 15. NE Lab (left) and S Lab (right) with locations of illuminance measurements indicated by the
green dots. ................................................................................................................................................ 39
Figure 16. (Left) Camera for HDR image capture. .................................................................................... 40
Figure 17. NE Lab (left) and S Lab (right) with locations/directions of HDR image capture marked by the
blue arrow. The numbers indicate the distance of each measurement from the façade. ...................... 40
Figure 18. Example HDR image taken in the S Lab at 12 p.m. on November 20. The DGP as analyzed by
Evalglare is 0.258 (imperceptible). ........................................................................................................... 40
Figure 19. Ocean Optics Spectrometer. The spectrometer is the blue tube mounted on the camera lens
and the black box below the camera that the tube is connected to. At the end of the tube is a light sensor
which, as mounted, captures vertical light. .............................................................................................. 41
Figure 20. NE Lab (left) and S Lab (right) with locations and directions of spectrometer measurements
indicated in orange. The lighting spectrum was recorded at each location in the N, S, E, and W direction.
The numbers indicate the distance of the measurement from the façade. ............................................ 42
Figure 21. Sample light spectrum. A lot of daylight mixed with fluorescent lighting as evidenced by the
spikes in wavelength around 550 and 600nm. ......................................................................................... 42
Figure 22. O.M.G. “light from windows” question dialog and response. ................................................. 43
Figure 23. Interior shade positioning for the east (top) and north (bottom) façades in the NE Lab. The
blue panels represent clear glazing with complete view to the outdoors, the light blue/white panels
represent translucent panels, and the dark gray shading represents the interior shades as they were
positioned throughout the duration of the study. The east façade is 66% occluded by shades and the
north façade is 36% occluded. .................................................................................................................. 46
Figure 24. Interior shade positioning for the south façade in the S Lab. The blue panels represent clear
glazing with complete view to the outdoors, the light blue/white panels represent translucent panels,
and the dark gray shading represents the interior shades as they were positioned throughout the
duration of the study. The façade is 28% occluded by shades. ................................................................ 47
Figure 25. NE Lab illuminance map comparison with (right) and without (left) electric lighting at 9:30 a.m.
on October 30. The percentage indicates the amount of the total light that was from sunlight. ........... 48
Figure 26. NE Lab illuminance map comparison with shades as used (left) and with shades up (right) on
the east façade at 9:30 a.m. on October 30. ............................................................................................ 48

9

Figure 27. NE Lab illuminance map comparison of morning (left), noon (center), and afternoon (right) on
November 13. ........................................................................................................................................... 49
Figure 28. S Lab illuminance map comparison with (right) and without (left) electric lighting at 11:30 a.m.
on November 3. The percentage indicates the amount of the total light that was from sunlight. ......... 50
Figure 29. S Lab illuminance map comparing morning (left), noon (center), and afternoon (right) on
November 10. ........................................................................................................................................... 50
Figure 30. S Lab illuminance map comparing morning (left), noon (center), and afternoon (right) on
November 20. ........................................................................................................................................... 51
Figure 31. NE Lab diagram of image capture for glare analysis. The blue arrows indicate the location of
the camera (measured from the east façade) and the direction it was facing. An example image of each
of the four locations is provided for context of what the camera was capturing. ................................... 53
Figure 32. S Lab diagram of image capture for glare analysis. The blue arrows indicate the location of the
camera (distances measured from the south façade) and the direction it was facing. An example image
of each of the four locations is provided for context of what the camera was capturing. ...................... 55
Figure 33. (Left) NE Lab floor plan with location and direction of spectrometry measurements. The
distance are measured from the east façade. (Center) View of center aisle looking toward the east
façade. (Right) View of center aisle looking towards the west wall. ........................................................ 57
Figure 34. Lighting spectrum in the NE Lab, 5 ft from the façade, recorded on November 13 at 10 a.m.
Percent melatonin suppression is shown in the upper left corner of each graph. .................................. 58
Figure 35. Lighting spectrum in the NE Lab, 15 ft from the façade, recorded on November 13 at 10 a.m.
Percent melatonin suppression is shown in the upper left corner of each graph. .................................. 58
Figure 36. Lighting spectrum in the NE Lab, 25 ft from the façade, recorded on November 13 at 10 a.m.
Percent melatonin suppression is shown in the upper left corner of each graph. .................................. 59
Figure 37. Lighting spectrum in the NE Lab, 25 ft from the façade, recorded on November 13 at 10 a.m.
Percent melatonin suppression is shown in the upper left corner of each graph. .................................. 59
Figure 38. (Left) S Lab floor plan with location and direction of spectrometry measurements. The distance
are measured from the south façade. (Right) Photos of the S Lab in each of the three aisles. The top row
of photos looks towards the back of the lab and the bottom row looks towards the south façade. ...... 61
Figure 39. Lighting spectrum in the S Lab, 5 ft from the façade, recorded on November 20 at 10 a.m.
Percent melatonin suppression is shown in the upper left corner of each graph. .................................. 61
Figure 40. Lighting spectrum in the S Lab, 22 ft from the façade, recorded on November 20 at 10 a.m.
Percent melatonin suppression is shown in the upper left corner of each graph. .................................. 62

10

Figure 41. Lighting spectrum in the S Lab, 11 ft from the façade, recorded on November 20 at 10 a.m.
Percent melatonin suppression is shown in the upper left corner of each graph. .................................. 62
Figure 42. Lighting spectrum in the S Lab, 25 ft from the façade, recorded on November 20 at 10 a.m.
Percent melatonin suppression is shown in the upper left corner of each graph. .................................. 63
Figure 43. Lighting spectrum in the S Lab, 3 ft from the façade, recorded on November 20 at 10 a.m.
Percent melatonin suppression is shown in the upper left corner of each graph. .................................. 63
Figure 44. Location of participant workstations in the Jorgensen Lab labeled with identifying number.65
Figure 45. HDR images taken at Desk 6 for comparison of DGP with the shades up and down. (Left) Facing
towards the occupant’s desk. (Right) Facing towards the nearest façade from the occupant’s desk. ... 65
Figure 46. Lighting spectrums and corresponding HDR images for Desk 4. (Left) Facing the desk. (Right)
Facing the north façade. ........................................................................................................................... 66
Figure 47. Lighting spectrums and corresponding HDR images for Desk 11. (Left) Facing the south façade.
(Right) Facing the desk. ............................................................................................................................. 67
Figure 48. Lighting spectrums and corresponding HDR images for Desk 6 with shades up and shades
down. (Left) Facing the south façade. (Right) Facing the desk. (Top) Shades down. (Bottom) Shades up.
................................................................................................................................................................... 67
Figure 49. Boxplot of O.M.G. responses. (1) Too low it bothers me, (2) low but I am not bothered, (3)
neutral, (4) high but I am not bothered, (5) too high it bothers me. ....................................................... 69
Figure 50. O.M.G. survey results displaying responses to satisfaction with daylight. Each histogram
represents a different response. (1) Response “too low, it bothers me” (2) Response “low but I am not
bothered” (3) Response “neutral” (4) Response “bright but I am not bothered” (5) Response “too bright,
it bothers me” is not shown due to only one instance of this response. ................................................. 70
Figure 51. Overall, how satisfied are you with the daylight at your desk workspace? -3 = very
dissatisfied/too dim, 0 = neutral, 3 = very dissatisfied/too bright ........................................................... 71
Figure 52. Overall, how satisfied are you with the daylight in the lab you work most frequently? (if you
work in a lab) ............................................................................................................................................. 72
Figure 53. Overall, how satisfied are you with views to the outdoors at your desk workspace? ............ 72
Figure 54. Overall, how satisfied are you with your visual connection to the outdoors when the roller
shades were down in the lab? .................................................................................................................. 73
Figure 55. How satisfied are you with glare in your workspace(s)? ......................................................... 73

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Figure 56. How often do you adjust the shades in your workspace(s)? ................................................... 74
Figure 57. How often do you adjust the electric lighting in your workspace(s)? ..................................... 74
Figure 58. HDR images of Desk 2 used to calculate DGP. ......................................................................... 80
Figure 59. HDR images of Desk 6 with shades up and down. Percentages in the lower left corner of each
image are the melatonin suppression values. .......................................................................................... 82
Figure 60. HDR images of Desk 13. Percentages in lower left corner of each image are the melatonin
suppression values. ................................................................................................................................... 82
Figure 61. HDR images of Desk 3. Percentages in lower left corner of each image are the melatonin
suppression values. ................................................................................................................................... 83

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LIST OF TABLES

Table 1. Façade occlusion by interior shades in the NE Lab. .................................................................... 45
Table 2. Façade occlusion by interior shades in the S Lab. ....................................................................... 46
Table 3. Summary of horizontal illuminance results in the NE Lab measured in terms of percent of floor
area above 100 and 300 lux. ..................................................................................................................... 51
Table 4. Summary of horizontal illuminance results in the S Lab measured in terms of percent of floor
are above 100 and 300 lux. ....................................................................................................................... 52
Table 5. Daylight Glare Probability measurements in the NE Lab (unless otherwise noted, the shades
were positioned as used and the sky was clear). ..................................................................................... 53
Table 6. Daylight Glare Probability measurements in the S Lab. ............................................................. 55
Table 7. Summary of spectrometry data collection in the NE Lab. The numbers shaded grey are percent
melatonin suppression. Each block is one location and time, and the arrow points north. .................... 60
Table 8. Summary of spectrometry data collection in the S Lab. The numbers shaded grey are percent
melatonin suppression. Each block is one location and time, and the arrow points north. .................... 64
Table 9. Daylight Glare Probability as measured at occupant desks. Numbers in red indicate DGP that
exceeds 0.3. .............................................................................................................................................. 66
Table 10. Melatonin suppression as measured at occupant desks. Numbers in red indicate values less
than 20%. .................................................................................................................................................. 68
Table 11. Summary of laboratory shade occlusion .................................................................................. 77
Table 12. Summary of laboratory illuminance results. ............................................................................. 78
Table 13. Summary of conclusions. .......................................................................................................... 92

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1 INTRODUCTION

1.1 The Importance of Studying Buildings

1.1.1 Sustainable Design and Metrics of Success

Following the development of mechanical heating, cooling, and ventilation systems and prior to the
establishment of building energy codes in the late 1970s, buildings were designed under the assumption
of limitless energy (EPA 2015). Passive strategies were of little concern because, it was thought, the indoor
environment of a building could be controlled however desired simply by inputting more energy.
Following the energy crises of the 1970s however, the United States began developing energy codes, with
California being the first to implement theirs in 1978 (EPA 2015). In present day, energy is no longer
viewed as a cheap limitless resource; it is now well understood that the Earth’s resources are limited and
that current modes of development are unsustainable.

In response, architects and others in the building industry have begun to develop sustainable practices.
The Architecture 2030 Challenge is one way in which architects are working towards minimizing the
impact of buildings on the Earth’s resources. The Architecture 2030 Challenge is a goal to reach carbon-
neutrality by 2030, and a majority of top architecture and planning firms are participating along with the
American Institute of Architects (AIA), the American Society of Heating, Refrigerating and Air-
Conditioning Engineers (ASHRAE), the U.S. Conference of Mayors, the U.S. federal government, the
Royal Architectural Institute of Canada, and the Ontario Association of Architects, just to name a few
(Architecture 2030 2015).

A number of metrics have been developed in the building industry in order to measure the sustainability
of a project and award and recognize exemplary performance. Most popular of these in the United States
is LEED, or Leadership in Energy and Environmental Design, the rating system developed by the U.S.
Green Building Council (USGBC 2014). One shortcoming of LEED for New Construction is that
certification is awarded almost entirely based on design and construction documentation and very little on
actual building performance. So, although a building’s performance can be predicted through simulation
in terms of thermal gains and losses, daylighting, and overall energy consumption, the only way to truly
know if the building is meeting its performance expectations is to study the building once in use,
something not required by LEED.

1.1.2 Post-Occupancy Evaluation

The study of a building once in use is referred to as a post-occupancy evaluation (POE). A POE, as defined
by Wolgang F.E. Preiser who has written extensively on the topic, is “the process of evaluating buildings
in a systematic and rigorous manner after they have been built and occupied for some time” (Preiser, The

14

Evolution of Post-Occupancy Evaluation Toward Building Performance and Universal Design Evaluation
2002). Preiser has said that POE is a “process of systematic data collection, analysis, and comparison with
explicitly stated performance criteria pertaining to occupied built environments” (Hadjri and Crozier 2009,
22). The word “systematic” is quite important to these definitions. In an informal sense, people evaluate
buildings on a regular basis; they notice when a building is too hot or too cold, too dark, too loud, too
humid, or too drafty. However, the feedback loop between design and occupant experience is not
employed as a standard part of architectural practice the way that, for example, a software developer seeks
constant feedback from users (Hadjri and Crozier 2009).

Formal, systematic POEs are a relatively recent development in the history of the building industry.
According to Preiser, who cites some of his own studies, POEs emerged in the 1960s, mainly in the
academic realm (Preiser 1994, 95). In 1965, the Royal Institute of British Architects incorporated a final
feedback stage into the “Plan of work” in their handbook in order to systematically identify the successes
and failures of buildings (Hadjri and Crozier 2009, 23). In the decades following, POEs were completed
on hospitals, schools, and government facilities, buildings of significant value to the welfare of the general
public (Preiser 1994, 95). Today, POEs are conducted in a similar manner, mainly by academics or in
buildings significant to the public or government.

Despite some professional efforts and interest amongst the academic community, POEs have not become
a standard of practice within the building industry (Hadjri and Crozier 2009). There appear to be two
major reasons for this cited throughout the literature on the topic. The first is a matter of finances; clients
and owners are unlikely to pay for a POE to be completed unless they can see a probable profitability from
it (Hadjri and Crozier 2009, 30). The second reason is a fear of liability on both the side of the designers
and the side of the owners (Hadjri and Crozier 2009, 30). Who is responsible if the results of the study are
negative? With the knowledge available, owners may feel obligated to correct the issues, but it will
probably cost them more than they would like to spend to remedy the problem. Will the owner blame the
designer? Will the designer be legally liable? How will it impact their reputation? The potential of
litigation and/or negative reputation is enough to make owners and designers extremely hesitant towards
a post-occupancy evaluation of their buildings (Hadjri and Crozier 2009, 30).

However, POEs offer many benefits to designers, owners, facility managers, and users alike (Hadjri and
Crozier 2009). By determining what design strategies do and do not work well in existing buildings,
designers can continually improve their designs to provide better quality buildings to their clients, backed
up with data from currently operating buildings (Hadjri and Crozier 2009, 25). Owners and facility
managers can benefit by determining ways to operate their buildings more effectively, and users benefit
from a system in which they can express what is and is not working for their necessary functions (Hadjri
and Crozier 2009, 25).

15

1.1.3 The Role of Daylighting in Sustainable Building Design

One of the largest contributions to energy consumption in commercial buildings is lighting (U.S. EIA
2003). Therefore, daylighting is an important component of a low-energy building design. But daylighting
doesn’t just have an effect on building energy consumption, it also has a significant impact on occupant
health and well-being. Studies have shown that views to the outdoors (which often come hand-in-hand
with daylighting design) are important to occupant well-being (Jackson 2003). In addition, daylight is
important for our circadian systems which regulate our sleep/wake cycles as well as many other biological
processes (Lockley, Brainard and Czeisler 2003).

1.1.4 The Jorgensen Laboratory

The subject of this study is the Jorgensen Laboratory, a university building located in Southern California.
In 2010-2011 it was heavily renovated, transformed from its original brutalist form to a modern, highly-
glazed building. To reflect the goals of Caltech and the clean-energy focused research that the building
would house, the designers stressed sustainable solutions and energy efficiency. One of the major goals
of the renovation was improved daylighting.

The building was studied in order to compare daylighting design intentions to daylighting design
outcomes.

1.2 Important Terminology

1.3.1 Post-Occupancy Evaluation

A post-occupancy evaluation (POE) is an evaluation of a building once construction has been completed
and the building has been occupied. A POE can be a survey of building occupants and/or a measurement
of the indoor environment of the building. The benefit of completing a POE is to determine whether or
not the design strategies implemented are producing the outcomes that were desired, and, from this, a
design team can learn from the successes and failures of one building in order to better design future
buildings. (Hadjri and Crozier 2009)

1.3.2 Illuminance

Illuminance is density of luminous flux that is incident on a surface and oriented in a specific direction.
In this study, horizontal illuminance is measured, which is the luminous flux density incident on a
horizontal surface perpendicular to that surface. In SI units, illuminance is measured in units of lux
(lumens/m
2
). (DiLaura, et al. 2011)

16

1.3.3 Glare

Glare describes the phenomenon that occurs when luminance is too high or when the range of luminance
values within the field of vision is too large (i.e. the luminance ratio is too high). Glare can cause visual
discomfort or entirely impede vision. (DiLaura, et al. 2011)

1.3.4 Spectral Power Distribution

A spectral power distribution (SPD) is the distribution of radiant power of light at each wavelength along
the electromagnetic spectrum (DiLaura, et al. 2011).

1.3.5 Melatonin Suppression

Melatonin is a chemical naturally produced by the human brain which aids relaxation and sleep. Melatonin
production responds to light stimulus of the circadian system. Stimulus by daylight in the early hours of
the day triggers melatonin suppression, a reduction of the amount of melatonin the brain produces in order
to aid alertness during the daytime hours. (Lockley, Brainard and Czeisler 2003)

1.3 Study Boundaries

With any research project there are an infinite number of questions that could be explored. Resources and
time, on the other hand, are limited, and for this reason it is necessary to clearly define the boundaries of
the study being conducted.

This study investigated the successes of daylighting design in a laboratory building. The domain of the
study included the determination of whether the daylighting design strategies that were implemented in
the building are functioning as expected and such that the occupants are comfortable in their environment.
Only one building was studied, located in the warm, sunny climate of Southern California. The entirety
of the study was carried out in the autumn months of October and November 2015. Successful design
strategies in this environment may not necessarily be successful in other environments, and it was not
within the study boundaries to identify the best strategies, only to determine if the design strategies used
in this case are functioning as expected.

The rationale for choosing this domain is based on time constraints and the availability of buildings to
investigate. Gaining permission to complete a post-occupancy evaluation of a building and getting all of
the relevant parties involved to the necessary degree requires large amounts of coordination. In addition,
building owners and architects are not often willing to perform POEs as discussed previously.

17

1.4 Scope of Work

The scope of work consisted primarily of a post-occupancy evaluation of daylighting in a university
laboratory building located in Southern California. The post-occupancy evaluation designed for this study
included data collection (illuminance, glare, and spectrometry), and occupant surveys. The results of this
evaluation were used to analyze the success of the daylighting strategies implemented in the renovation.
Success was defined for the purpose of this study as the realization of intended/predicted design outcomes
in terms of daylighting properties and occupant comfort. The goals and related design strategies used in
the building’s renovation were identified and compared to the data collected during the POE to determine
if the daylighting design strategies translated into occupant satisfaction.

1.5 Chapter Structure

In the following chapter, more detailed background research is presented. Chapter 2 also includes previous
research that has been completed concerning POEs and the outcomes of sustainable and energy-efficient
building design. Information about the laboratory building being studied is detailed in Chapter 3.

Following the background chapters is the actual content of the study. The methodology is described in
Chapter 4, which outlines exactly how the study was completed, what assumptions were made, and the
rationale behind each step of the research.

The analysis and results of the data collection are presented in Chapter 5. This chapter outlines what data
was collected and any interesting trends that emerged. Chapter 6 is the discussion chapter in which the
results of the study are interpreted. Finally, conclusions are presented in Chapter 7 which ties the research
back to the broader ideas presented in the introduction.

Following the actual content of the research, Chapter 8 presents the limitations of the study and ways that
future research could expand upon the findings.

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2 BACKGROUND

This chapter presents background information relevant to the study. A literature review of previous
daylighting POE studies is presented to review research that has already been completed by others, but
also to show in what ways this study differs. Daylighting metrics used in the study are also explained in
this chapter. These metrics include illuminance analysis using LEED metrics and Spatial Daylight
Autonomy, glare analysis using Daylight Glare Probability, and a thorough explanation of how
spectrometry analysis of lighting spectrum.

2.1 The Push for Better Performing Buildings

With the understanding that our current energy resources are finite and that fossil fuel consumption is
causing detrimental changes to the earth’s climate, the necessity for curbing energy consumption has been
recognized. The building sector is one of the largest consumers of energy, therefore a number of public
and private organizations have launched initiatives and set out plans for reducing building energy
consumption.

In 2008, the California Public Utilities Commission released the California Long Term Energy Efficiency
Strategic Plan in order to lay out a detailed plan to meet the state’s ambitious energy efficiency goals. The
plan incorporates industry targets, codes and standards, education, research, and local government
responsibilities to reach the energy efficiency goals (California Public Utilities Commission 2008). The
plan’s vision for the commercial building sector (which includes schools and colleges) is for all new
buildings and a significant percentage of existing buildings to be zero net energy (ZNE) by 2030, which
is the same goal of Architecture 2030 as discussed in Chapter 1 (California Public Utilities Commission
2008). Commercial buildings account for 38% of the state’s electricity consumption, and overall 34.5%
of that electricity is used for interior and exterior lighting, the largest end-use by far (cooling, the second-
highest consumption, uses 14.9% of the electricity consumed by buildings) (California Public Utilities
Commission 2008). The plan defines three strategies for reaching net zero energy goals: implementing
tougher codes and standards, using building benchmarking and advanced metering to improve operations
and maintenance practices, and expanding financing initiatives (California Public Utilities Commission
2008). California’s building energy efficiency code, Title 24, is one of the strictest in the country
(California Energy Commission 2012).

The importance of energy efficiency in buildings has gained much traction in the past decade. Those at
the forefront of building innovation are now also emphasizing the importance of human health and well-
being considerations in building design in conjunction with energy efficiency. It is one thing to reduce
energy consumption, but it is also important that people are happy, healthy, and productive in their
workspaces. This applies greatly to daylighting which serves both to reduce electricity consumption and
is also known increase human health and well-being (Aries, Aarts and van Hoof 2013).

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Although state and local codes exist to set minimum requirements for buildings, independent building
rating systems have been established to provide incentives for going above and beyond minimum code
requirements. Probably the most well-known and commonly used of these rating systems in the U.S. is
LEED (Leadership in Energy and Environmental Design). LEED offers a few credits for daylighting and
views, which will be discussed in Chapter 3. A common criticism of LEED is the lack of required
verification of LEED-certified buildings once they are in use (Newsham, Mancini and Birt 2009).

2.2 Post-Occupancy Evaluation and Daylighting

2.2.1 Literature Review of POE Studies

Many studies have been published reporting the results of post-occupancy evaluations. The studies cover
a variety of different building types and focus on different aspects of indoor environmental quality.
Summarized in this section are a number of post-occupancy evaluations which specifically studied
daylighting.

Most relevant to this study, Ying Hua and colleagues at Cornell University studied the effectiveness of
the daylighting design in a campus laboratory building that had received a LEED Gold rating. The building
in question is located in the northeast region of the U.S. and was studied for two weeks at the end of
February in 2009. The research objectives were to (1) evaluate the visual environment, (2) understand
occupant visual satisfaction, (3) evaluate the effectiveness of the daylighting design strategies, (4) identify
solutions, and (5) develop a method for lighting and visual comfort evaluation. They used a number of
methods to collect the necessary data, including occupant surveys and interviews, documentation of the
occupants’ visual environment at time of survey, instantaneous and continuous measurements of lighting
levels in workspaces, analysis of glare, documentation of all building features affecting the visual
environment, daylight simulation using Radiance, and measurements of outdoor sunlight. The data was
analyzed primarily through statistical analyses using SPSS software. In addition, the existing lighting
levels were compared to suggested levels, and the correlation of glare from both daylight and electric
lighting to occupant satisfaction was analyzed. The results were presented via bar graphs, box plots, and
tables of the statistical analyses and line graphs of the continuous lighting measurements. The study’s key
findings were that (1) the use of daylight was mostly well-received by the building occupants, (2)
horizontal shades were effective in creating a visually comfortable environment, (3) the lighting levels in
the building are higher than necessary and electric lighting is not fully integrated with daylighting features,
and (4) providing occupants with control over their visual environment correlated with higher satisfaction
(Hua, Oswald and Yang 2011).

A 2012 study by Kyle Konis, then at the University of California, Berkeley, studied the effectiveness of
daylighting strategies and visual comfort of occupants in a large office building in San Francisco, CA.
The office of interest was completed in 2007 and achieved a LEED Silver rating. The research objectives

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were to (1) “evaluate the outcomes of specific daylighting design strategies on daylight availability,
electrical lighting energy reduction and visual comfort over a range of daily and seasonal variation in sun
and sky conditions,” (2) “examine the impacts of modifications to the building façade by…occupants…on
daylighting effectiveness and visual connection to the outdoors,” (3) “demonstrate a method for collecting
repeated-measures of occupant subjective assessments paired with physical measurements using a novel
desktop polling station device,” and (4) “identify guidelines to inform and improve the daylighting design
practices implemented in the building evaluated.” The performance of daylighting design measures was
evaluated four ways: (1) time-lapse photos to record occupant adjustment of shades (and measure
luminance at their workstations), (2) use of a “novel desktop polling station device” for occupants to report
visual comfort as well as measure workstation luminance, (3) monitoring of electric lighting consumption,
and (4) “on-site observations and in-depth survey questionnaire.” The study was conducted in 2-3 week
phases throughout a year, with each participant involved in two of these phases. The results were analyzed
and presented in a number of different ways. “Overall subjective assessments” were presented as boxplots
of distribution of responses regarding satisfaction related to the visual environment. “Occupant shade
control behavior” is shown via a diagram of the participant’s work environment. “Measured daylight
illuminance in perimeter and core workstations” from daylight and electric lighting is presented in a
number of different tables and graphs such as to show the percentage of the day that daylight is above a
certain level or what percentage of lighting in a space is from daylight or electric through the day.
“Occupant subjective assessments” were analyzed in a number of different ways based on the responses
to survey questions and measured illuminance. The survey responses analyzed related to “perception of
daylight sufficiency,” “visual comfort,” and “subjective assessment of visual connection to outdoors.” The
study’s key finding is that despite the reduction in visual light transmittance from the shading devices,
occupants reported sufficient lighting levels to perform their work even when the lighting levels were
below recommended values (Konis 2013).

Another study was conducted in April 2011 by Yaik-Wah Lim and colleagues at Universiti Teknologi
Malaysia. They studied the impact of the façade design of a typical government office building on
daylighting quality. The large office tower, located in Johor Bahru, Malaysia, was constructed in 1978
and not designed with any consideration of daylighting. A previous study conducted by the group showed
that daylight was extremely insufficient to light the building’s offices, therefore the objective of this study
was to determine effectiveness of a number of modifications that could be made to the façade in order to
utilize daylighting for visual comfort. Two methods were used to collect the necessary data: (1)
illuminance meters were placed in a typical office facing south and on the roof to collect actual data and
(2) Radiance simulations of the existing conditions and modified façade scenarios were run. The results
were analyzed and presented in the following ways: (1) the actual office daylight levels were compared
to the required minimum by Malaysian standards, (2) line graphs of measured and simulated work plane
illuminance (WPI) and daylight ratios were shown for the existing and simulated scenarios, (3) a table
showing false color contours, mean daylight ratios, and uniformity ratios for each of the scenarios was
presented, and (4) a table of simulation photos and values show the results of a glare analysis. The key

21

finding of the study was that light shelves helped significantly in creating more uniform lighting and
reducing some but not all glare in the offices in comparison to the existing scenario with no overhang
shades. In addition, blinds can be used to successfully block glare when it occurs (Lim, et al. 2012).

2.2.2 Relevance of Jorgensen POE

The study of daylighting in the Jorgensen Lab is unique in a number of ways. It is a relatively small
laboratory building located in Southern California, a climate known for its ample sunlight. The building
itself was not built from scratch; it was a retrofit of an existing building and was therefore subjected to the
limitations of the original structure. In part a response to the “bunker-like” design of the original building
(but also as part of the sustainable design goals), the laboratory was intentionally designed to maximize
daylight use. It is this combination of factors which makes the Jorgensen Lab unique from previous
daylighting POEs.

Most daylighting studies include physical analysis of illuminance and glare, as did all of those referenced
in this section. Fewer, but still many, pair physical analysis with subjective occupant reports. The Cornell
lab study and San Francisco office building study referenced previously both performed surveys of
occupant satisfaction, whereas the study in Malaysia focused solely on the physical lighting properties in
the building. This study of the Jorgensen Lab aims to be more holistic, including both physical analysis
and occupant satisfaction. In addition to the standard metrics of illuminance and glare, this study includes
spectrometry analysis to measure light wavelength within the building (this is explained in detail later in
the chapter). The effect of light on human health is not new knowledge, however studying the lighting in
buildings in this capacity has not been done much, if at all.

2.3 Illuminance

Horizontal illuminance is the amount of light (or luminous flux) that hits a horizontal surface. It is
measured in lux (lumens/m
2
). Proper illuminance in buildings is important to performing our daily tasks.
Before electric lighting, buildings were reliant upon daylight to provide sufficient illuminance and were
designed accordingly. Daylighting became a less important design consideration after electric lighting,
however daylight is again being utilized to meet illuminance needs as energy efficiency becomes a major
priority of architecture.

The Illuminating Engineering Society defines two main metrics for evaluating daylight illuminance in
buildings: spatial daylight autonomy (sDA) and annual sunlight exposure (ASE) (Illuminating
Engineering Society 2013).

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2.3.1 LEED v2009 Daylighting Requirements

The newest version of LEED (LEED v4) requires the use of sDA and ASE metrics as explained in the
following sections, but the previous version of LEED (LEED v2009), for which the Jorgensen Lab was
designed, used different metrics. LEED v2009 has four options for meeting the requirements of the
daylighting credit (USGBC 2008). The first option, simulation, requires the designers to show through
computer simulations that “applicable spaces achieve daylight illuminance levels of a minimum of 110
lux and a maximum of 5,400 lux in a clear sky condition on September 21 at 9 a.m. and 3 p.m” (USGBC
2008). The second option, prescriptive, is simply a list of design requirements that must be met. The third
option, measurement, requires the designers to “demonstrate through records of indoor light
measurements that a minimum daylight illumination level of 110 lux and a maximum of 5,400 lux has
been achieved in the applicable spaces” (USGBC 2008). In both the simulation and measurement options,
LEED requires that 75% of the applicable floor area meet these metrics. The fourth option was to use a
combination of the previous options.

2.3.2 Spatial Daylight Autonomy (sDA)

“Spatial Daylight Autonomy (sDA) is a metric describing annual sufficiency of ambient daylight levels
in interior environments. It is defined as the percent of an analysis area that meets a minimum daylight
illuminance level for a specified fraction of the operating hours per year” (Illuminating Engineering
Society 2013). The standard for illuminance set by the Illuminating Engineering Society is 300 lux for
50% of the analysis time period (sDA300/50%), which is reported as the percentage of the analysis area in
the building which meets this minimum threshold (Illuminating Engineering Society 2013). Two levels
of daylight sufficiency are defined: Preferred Daylight Sufficiency and Nominally Accepted Daylight
Sufficiency. Preferred Daylight Sufficiency is reached when 75% or more of the analysis area is
sDA300/50% and Nominally Accepted Daylight Sufficiency is reached when 55% or more of the analysis
area is sDA300/50% (Illuminating Engineering Society 2013).

sDA is determined via daylight simulation of a 3D model of the building modeled as realistically as
possible. The time period of analysis is set for typical working hours from 8 AM to 6 PM, and the analysis
area is broken into a 1-2 ft grid. IES provides in depth specifications for proper simulation methods,
including the following specifications for the building model: interior shades shall be modeled such that
they are closed to block light whenever more than 2% of the analysis points receive direct sunlight;
windows should be modeled as constructed but with a dirt depreciation factor subtracted from the VLT;
interior surface reflectance should be modeled as measured if possible, otherwise default values are
specified; furniture and interior partitions should be modeled as accurately as possible (Illuminating
Engineering Society 2013). Important to note here is the assumption for the shades. It is assumed that
occupants will pull the shades down whenever there is direct sunlight in a space, but also that they will let

23

the shades back up when there is no longer direct sunlight. The accuracy of the model is heavily dependent
upon this assumption.

An example of spatial daylight analysis is shown in Figure 1, which was created based on data from this
study. The numbers in the grid indicate the percentage of hours during the analysis time period (which is
8 AM to 6 PM 365 days of the year) that the location is receiving more than 300 lux of sunlight. The
number below the grid indicates that only 11.91% of the analysis area exceeds the threshold of 300 lux
for more than 50% of the hours. This is below the nominally accepted daylight sufficiency.

Figure 1. Example of Spatial Daylight Autonomy (sDA). The numbers in the grid indicate the percentage of hours
during the analysis time period (which is 8 AM to 6 PM 365 days of the year) that the location is receiving more than
300 lux of sunlight. The number below the grid indicates that 11.91% of the analysis area exceeds the threshold of 300
lux for more than 50% of the hours.

2.3.3 Annual Sunlight Exposure (ASE)

“Annual Sunlight Exposure (ASE) is a metric that describes the potential for visual discomfort in interior
work environments. It is defined as the percent of an analysis area that exceeds a specified direct sunlight
illuminance level more than a specified number of hours per year” (Illuminating Engineering Society
2013). The threshold used to report ASE is the percentage of an area that is “exposed to more than 1000
lux of direct sunlight for more than 250 hours per year (ASE1000,250h)” in the case of no operable blinds
considered for the analysis (Illuminating Engineering Society 2013).

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The ASE analysis (also competed via simulation of 3D building model) does not include interior shade
usage as the metric is intended to measure the risk that glare presents in the analysis area, but other than
that ASE shall be modeled exactly the same as sDA (Illuminating Engineering Society 2013). ASE is
meant to be reported along with sDA, and smaller values are preferred, although there is no set maximum
and ASE is considered to be relative (Illuminating Engineering Society 2013).

An example of annual sunlight exposure analysis is shown in Figure 2. The numbers in the grid indicate
the percentage of hours during the analysis time period that the illuminance from the sun exceeded 1000
lux. The number below the grid indicates that 27% of the analysis area is above the threshold of 250 hours
above 100 lux.

Figure 2. Annual Sunlight Exposure (ASE). The numbers in the grid indicate the percentage of hours during the
analysis time period that the illuminance from the sun exceeded 1000 lux. The number below the grid indicates that
27% of the analysis area is above the threshold of 250 hours above 100 lux.

2.4 Glare

Glare describes the phenomenon that occurs when luminance is too high or when the range of luminance
values within the field of vision is too large (i.e. the luminance ratio is too high). Glare can cause visual
discomfort or entirely impede vision. (DiLaura, et al. 2011). Glare is notoriously difficult to quantify, in
part because the perception and discomfort caused by glare can vary widely from person to person. A
number of glare metrics have been developed, however, all consisting of four main factors which
contribute to glare: the luminance of the glare source, the size of the glare source, the angle of the glare
source from the line of sight, and the luminance of the background environment (Wienold and
Christofferson 2006). The first two are positively correlated with glare perception, meaning that an
increase in source luminance and increase in source size will increase glare. The latter two causes of glare

25

are negatively correlated, meaning that the greater the angle of the source from the line of site and the
higher the background luminance, the less glare there will be (Wienold and Christofferson 2006).

A widely used method for analyzing the potential for glare is Daylight Glare Probability (DGP), which
was developed by Jan Wienold and Jens Christofferson in 2006. Instead of attempting to measure glare in
terms of magnitude, DGP evaluates glare in terms of the probability that it will be perceived as disturbing
(Wienold and Christofferson 2006). The metric was created by studying individuals’ responses to glare in
a controlled test environment. The resulting equation is as follows (Wienold and Christofferson 2006):

𝐷𝐷𝐷𝐷𝐷𝐷 = 𝑐𝑐 1
∙ 𝐸𝐸 𝑣𝑣 + 𝑐𝑐 2
∙log � 1+ �
𝐿𝐿 𝑠𝑠 , 𝑖𝑖 2
∙ 𝜔𝜔 𝑠𝑠 , 𝑖𝑖 𝐸𝐸 𝑣𝑣 𝑎𝑎 1
∙ 𝐷𝐷 𝑖𝑖 2
𝑖𝑖 � + 𝑐𝑐 3

where Ev is vertical eye illuminance, Ls is the luminance of the glare source, ωs is the solid angle of the
glare source, P is the position index, and c1, c2, and c3, are constants determined by the trends found in the
study (Wienold and Christofferson 2006). The researchers created a RADIANCE-based program called
Evalglare which can be used to complete a glare analysis using the DGP metric. Evalglare uses an HDR
image created from photos taken using a fisheye lens, determines the values of each of the four variables
in the DGP equation, and produces the daylight glare probability for the image.

2.5 Spectral Power Distribution

A spectral power distribution (SPD) is the distribution of radiant power of light at each wavelength along
the electromagnetic spectrum (DiLaura, et al. 2011). This is measured using a device called a
spectrometer.

The connection between illuminance and vision is well understood and has been used as a measure of
light sufficiency for a long time, but there is also an important connection between light and the human
circadian system which is not visibly evident. In addition to rods and cones which produce vision, humans
also have “intrinsically photosensitive retinal ganglion cells,” which respond to light in a non-visual
manner (M. S. Rea, et al. 2005). The difference in response to light between vision and the circadian
system is illustrated by the graph in Figure 3.

26

Figure 3. Spectral response of vision and circadian systems. While our visual systems respond ideally to wavelengths
around 550 nm, our circadian systems respond best to blue light around 480 nm (American Society for Photobiology
2010).

While the human visual system responds ideally to wavelengths of light around 550 nm (green/yellow
light), the circadian system responds best to wavelengths around 480 nm (blue light) (Lockley, Brainard
and Czeisler 2003). Among many other functions, the circadian system requires appropriate wavelengths
of light in order to regulate our sleep/wake cycle by means of melatonin production and suppression
(Lockley, Brainard and Czeisler 2003). This means that even though illuminance may be sufficient for
visual comfort, the light may not be sufficient for adequate melatonin suppression. Melatonin is a chemical
released by the brain to aid relaxation in preparation for sleep, and proper wavelength light is necessary
to suppress melatonin production to aid alertness during the day (Lockley, Brainard and Czeisler 2003).

Natural sunlight, which carries light of wavelengths across the entire visible light spectrum, peaks around
480 nm, the ideal wavelength for the circadian system to trigger melatonin suppression. Conversely,
fluorescent lights common in buildings have peaks of blue, green, and red light wavelengths. A
comparison of SPDs for sunlight and fluorescent light is shown in Figure 4.

Figure 4. (Left) Spectral power distribution of natural sunlight, peaking in the range of blue light around 480 nm.
This results in 67% melatonin suppression. (Right) Spectral power distribution of fluorescent light (mixed with
natural sunlight) with dramatic peaks in the red, green, and blue ranges. This results in 42% melatonin suppression.
(Please note that that y-axes are at slightly different scales).

27

Sunlight is preferable for melatonin suppression. One study found that 460 nm light caused double the
melatonin suppression of light of 555 nm (Lockley, Brainard and Czeisler 2003). In the example in Figure
4, sunlight equates to 67% melatonin suppression (nearing the upper bound of possible melatonin
suppression because production cannot be shut off entirely) and fluorescent light mixed with low sunlight
equates to 42% melatonin suppression. There is no standard value for how much melatonin suppression
is ideal for human health. While any amount of suppression is technically beneficial, for the purposes of
this research desirable melatonin suppression will be defined as anything above 20%. Twenty percent
suppression can be achieved by 100 lux of sunlight (M. Rea, et al. 2012), a reasonable illuminance for an
interior daylit space according to the daylight requirements in LEED v2009.

2.6 Chapter Summary

This chapter provided background information on the building performance goals, post-occupancy
evaluations, and daylighting metrics. The building industry is currently experience a push for buildings
that are more energy efficient and better for the health and well-being of the occupants. This is evident in
numerous codes, guidelines, and rating systems which seek to guide designers and set minimum
requirements that owners must meet. In the academic realm, many daylighting studies have been carried
out to evaluate how well a building is functioning, which is defined differently for different studies. Some
studies are concerned with measuring only the physical, objective functionality of a building (e.g. Does
that building meet the requirements of codes and standards?), while other studies have pushed for deeper
evaluation which considers occupant satisfaction as an important indicator of how well a building
functions. This study in particular paired physical measurements wavelength with occupant satisfaction
surveys. The physical measurements of illuminance, glare, and lighting spectrum/wavelength are defined
in this chapter.

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3 JORGENSEN LABORATORY BACKGROUND

The building of interest in this study is the Earle M. Jorgensen Lab located in Pasadena, CA. The building
was originally constructed in 1974 and housed a computer lab. In 2011 the building was heavily renovated,
with only the structure being preserved, and the building was converted to laboratories to support
sustainable energy research. In order to gain an in depth understanding of the Jorgensen Lab’s design and
construction, interviews of the building’s project team were conducted and archival documents were
gathered and studied. This chapter presents the findings of this archival background research, including
the goals of the renovation and the daylighting strategies that were (and were not) implemented along with
the rationale for the decisions that were made.

3.1 Renovation Design Goals

The Jorgensen Laboratory, located in Pasadena, CA, was originally constructed in 1974 and housed a
30,000 square-foot computer lab (Buro Happold Engineering 2015). Figure 5 is a photograph of the
building taken from the rear before the renovation project was started in 2011. On all four sides of the
building the original façade consisted of large concrete overhangs, which blocked daylight and views to
the outdoors. It was due to these daylight-blocking features that one of the main goals of the renovation
was to bring ample daylight into the building (pers. comm. JFAK Architects 2015).

Figure 5. Jorgensen Lab in 2011 before renovations began. The façade consists of large concrete overhangs. This view
is of the rear of the building. (JFAK Architects 2015)

29

Overall, the renovation, which was completed in 2012, included replacement of the façade, HVAC, and
lighting systems, and reuse of the building’s original structure. To reflect the institution’s commitment to
sustainability and the aims of the research being conducted within the building, sustainability and energy-
efficiency were the guiding principles in the design of the building renovation. The general sustainability
objectives included the following (JFAK Architects 2015):

1) Reuse of the existing building structure
2) Passive design to reduce energy use
3) Active strategies to reduce energy use
4) Energy-efficient mechanical systems
5) Plumbing and landscape water use reduction
6) Material selection for exceptional indoor air quality

The previously unused balcony that encircled the top floor was enclosed in the renovation, adding 4,700
square-feet of interior space for laboratories, and the building was also expanded by the addition of an
entrance pavilion which is used as an educational space for visitors and an informal meeting space for
researchers. Figure 6 is a diagram of this façade retrofit process and entry pavilion addition. Figure 7 is a
photograph of the building taken of the rear (north side) of the building in 2012 after the renovation was
completed.

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Figure 6. Diagram of façade retrofit process, which included removing the large concrete overhangs on the upper two
floors, extending the top floor façade outward to encompass what was previously a balcony, and replacing the patio
and bridge entrance with a pavilion. (JFAK Architects 2015)

Figure 7. Jorgensen Lab at the California Institute of Technology in 2012 after the renovation was completed. This is
a view of the rear/north façade. (JFAK Architects 2015)

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3.2 Daylighting Design Considerations & Strategies

Through archival research and conversations with the project’s architect, the daylighting design strategies
used in the building were determined.

3.2.1 Façade Design

The façade is critical to the daylighting design. The goal of the designers was to open the building up to
let in daylight and views to the outdoors. The large concrete overhangs were removed on both levels to
allow for better views and more natural light, and the façade was extended to enclose the entire second
floor balcony. The new façade consists almost entirely of insulated glazing units with a summer daytime
U-value of 0.28 Btu/hr-ft
2
-°F that extends from waist height up to the ceiling. Most of the units are clear
glass with a visible light transmittance of 50%. On the second floor, the façade is also interspersed with
silk-screened insulated glazing units. The silk-screening has 100% coverage and a visible light
transmittance of 12%. All of the windows are equipped with interior, “view-preserving” roll-up shades
with an openness factor of 5% that blocks most of the sunlight but preserves some of the view to the
outdoors. An example of the “view-preserving” shades and their effect is shown in Figure 8.

Figure 8. Example of view-preserving shades in use in the Jorgensen Lab.

Figure 9 shows before and after cross-section diagrams of the façade and indicates the change in views
due to the renovation. Notice that a large space has been consumed by the drop ceiling due to the large
demands of the laboratory ventilation systems and equipment requirements.

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Figure 9. Before and after cross-sections and photos of the façade. Before the retrofit, large concrete overhangs
blocked sunlight and the view to outside. After the retrofit, the views are enhanced and sunlight penetrates deep into
the space. (JFAK Architects 2015)

Trees provide some shade on the south (front) and east sides of the building and the west side is shaded
by a taller building. The north façade, which naturally never receives direct sunlight, is the only side of
the building that is completely exposed, therefore the decision was made (along with financial
considerations) to build the same façade on all four sides of the building (Kessner 2015). The second floor,
west façade does not include any glazing due to the layout of the labs and the proximity to the neighboring
building.

A number of the second floor windows also have vertical and horizontal fins that box the section of
window. Though mainly for visual interest and texture, the vertical fins provide some shade to the east
side of the building.

3.2.2 Program Considerations

The placement of labs and office spaces was based on access to daylight. Spaces such as conference rooms,
kitchens, and bathrooms that are only temporarily occupied were placed in central locations where there
is not access to daylight. Permanent offices, write-up spaces for graduate students, and laboratories were
placed at the perimeter of the building, mostly on the south, east, and north sides, in order to have access
to ample daylight and views to the outdoors. The basement level, which has some access to sunlight on
the south side, but is below grade on the north side, was utilized to house light-averse laboratories. This
makes good use of the basement without depriving any of the spaces from access to daylight.

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3.2.3 Other Daylighting Features

Other daylighting features include the technological, such as daylight dimming and occupancy sensors in
some of the spaces. All of the doors in the building have a glass window and all of the conference rooms
have one entirely glass wall. The skylight above the stairway atrium also brings daylight into some of the
hallways on the first and second floors.

3.2.4 Daylighting Strategies Not Used

A few of the architect’s desired daylighting strategies were excluded during the value engineering process.
The first of these was light shelves. Light shelves were eliminated in the write-up spaces because it was
argued that the spaces were not deep enough for the light shelves to be effective. They were eliminated in
the lab spaces because it was thought that the low ceiling and crowding of lab equipment would prevent
the light shelves from being effective (Kessner 2015).

The second daylighting strategy that was not able to be implemented was light tubes. The architect wanted
to bring light into the inner hallways near the core of the building by means of light tubes. The structural
engineer would not allow this to be done because it would be detrimental to the structural integrity to
punch holes through the waffle slab (Kessner 2015).

3.2.5 LEED Daylighting Credit

The Jorgensen Laboratory received a LEED Platinum rating under LEED for New Construction 2009
(LEED v2009). As part of that, the building earned the credit for daylighting in the Indoor Environmental
Quality (IEQ) category. The daylighting credit in LEED v2009 provides four options (simulation,
prescriptive, measurement, or a combination) for designers to show that daylighting has been achieved in
at least 75% of the regularly occupied spaces of the building (USGBC 2008). Using the simulation method,
LEED requires that applicable building spaces receive a minimum of 110 lux (10 fc) and maximum of
5,400 lux (500 fc) from daylight on September 21 at 9 a.m. and 3 p.m assuming clear sky conditions
(USGBC 2008). It also states that if “view-preserving” shades are implemented to block glare that only
the minimum illuminance requirement must be met (USGBC 2008). The Jorgensen design team was not
able to meet the simulation criteria and instead opted for the measurement option (Kessner 2015). The
measurement option requires the same illuminance criteria to be met, but instead of simulating the building
the design team takes real measurements once building construction is complete (USGBC 2008). Using
this method, the Jorgensen design team was able to show that the building meets the minimum daylighting
requirements in 75% of the occupied spaces. The results of these measurements for the two second-floor
labs which are the subjects of this study are shown in Figure 10. The northeast corner lab meets the
daylighting requirement over the entire space, and the south facing lab meets the daylighting requirement
except for the last row of measurements which are about 30 ft from the façade.

34

Figure 10. LEED Daylighting credit verification measurements in foot candles. (Left) Northeast corner lab: 100% of
the area meets required daylighting of >10 fc. (Right) South facing lab: only the back row of measurements does not
meet the >10 fc daylighting requirement. (Kessner 2015).

The latest version of LEED (LEED v4) has much more stringent requirements for meeting the daylighting
credit and also offers 1-3 points depending on the level of daylighting implemented, whereas LEED v2009
offered only 1 point and had relatively simple requirements. LEED v4 gives two different options for
demonstrating compliance via simulation. The first simulation option uses Spatial Daylight Autonomy
(sDA) and Annual Sunlight Exposure (ASE), requiring sDA300/50% of at least 55% to earn 1 point and 75%
to earn 2 points (USGBC 2014). In addition, it requires that ASE1000,250 is no more than 10% (USGBC
2014). The second option for simulation uses illuminance calculations. This requirement is similar to
LEED v2009 except that the range of acceptable illuminance has been changed to 300-3,000 lux, and
achieving this in 75% of the regularly occupied spaces will earn just 1 point, while achieving daylighting
in 90% of the spaces will earn 2 points (USGBC 2014). The measurement option is also similar except
for the same change in acceptable illuminance range (USGBC 2014). In LEED v2009, 110 lux was
considered sufficient for daylighting, but LEED v4 now requires at least 300 lux to be considered
sufficient daylight. So although the Jorgensen Lab meets the requirements of LEED v2009, it may not
meet the new requirements in LEED v4.

35

3.3 Chapter Summary

This chapter presented the background research of the Jorgensen Laboratory. The building was originally
constructed in the 1970s and renovated in 2011. The renovation was heavily focused on promoting
sustainable design practices and especially on opening up the once heavily shaded building to provide
daylight throughout. Interviews with the architecture and engineering design teams revealed project goals,
decision-making rationale, and provided important information on the daylighting strategies that were and
were not implemented in the final renovation design. The design team was able to earn the daylighting
credits under LEED v2009. The information presented in this chapter is important to the study as it
provides for one half of the comparison between design intents and outcomes. The outcomes and
comparisons will be presented in the following chapters.

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4 METHODOLOGY

This chapter outlines and details the methodology used for the post-occupancy evaluation of daylighting
in the Jorgensen Lab. The POE consisted of three major components: (1) physical data collection of labs
and desk spaces, (2) occupant survey, and (3) daylight simulation. A diagram of the methodology is shown
in Figure 11. The POE was designed to measure/investigate the façade materials and construction, human
comfort, and the lighting physics within the building. These correlate to the research questions:

1) Façade: Does the achieved visible light transmittance (VLT) of the façade and components in use
match what was intended by the designer?
2) Physical Light Properties:
a. Are the horizontal daylight illuminance levels intended by the designer being achieved?
b. Is there a high potential for glare discomfort?
c. Is the spectral power distribution from daylight sufficient for human health and well-being,
specifically in regards to melatonin suppression?
3) Human Comfort: What percentage of occupants are satisfied with daylight and views in their
workspaces?

Figure 11. Study methodology flowchart.

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4.1 Physical Data Collection

Data of physical lighting properties in the building was collected using a number of specialized
instruments and methodological observation. The types of data collected were the positions of interior
shades, illuminance, HDR images to analyze glare, and measurements of spectral power distribution.
Physical data was collected in two different types of spaces: laboratories and at occupant desk spaces.

Data was collected in two of the three largest second floor laboratories on numerous days and at varying
times of the day. One of the labs is at the northeast corner of the building and the other is on the south side
of the building (Figure 12). The third, and largest lab, on the southwest corner of the second floor was not
studied due to the fact that it has a relatively small amount of glazed façade at its perimeter and was not
intended by the designers to be a daylit space (Kessner 2015). No laboratories exist on the first floor, and
the ground floor labs are windowless as they are used for light-sensitive experiments.

Figure 12. Jorgensen Lab second floor. Of the 3 major labs (highlighted) the NE and S Labs were studied. The SW
Lab was no studied due to minimal glazing and no daylighting design intention.

At desk spaces, data was recorded only during the time of day when the space received direct sunlight
(unless the space had only north-facing windows). The desk spaces studied were of those occupants who
volunteered to participate in the occupant survey and were located in various parts of the building on all
three floors. All of the data collection occurred over six weeks during October and November 2015.

38

4.1.1 Interior Shade Positioning

The interior shade positions were documented by observation and photo record. In the laboratories, which
were visited frequently over the duration of the study, the shade positions were recorded during each visit
if the positions had changed. The positioning of the interior shades was important to record due to the
significant impact that the shades have on the daylighting within the building. At the desk spaces, the
shade positioning was recorded only at the time of physical data collection.

Figure 13. Example photo of shade position documentation. Pictured here is the east façade in the NE Lab on
November 13 at 10 a.m.

4.1.2 Illuminance

Horizontal illuminance was measured using a handheld illuminance meter (Figure 14). In the laboratories,
illuminance was measured in the center of each of the aisles at 0, 10, 20, and 30 feet from the façade
(Figure 15). The illuminance meter was held 3 ft above the floor for each measurement. All of the same
overhead lights were switched on during each data collection, so illuminance was also measured at night
to determine what percentage of the light during the day is from daylight.

Figure 14. Illuminance meter.

39

Figure 15. NE Lab (left) and S Lab (right) with locations of illuminance measurements indicated by the green dots.

4.1.3 Glare

In order to analyze glare, a series of photographs were taken throughout the labs and at desk spaces using
a HDR-enabled camera equipped with a 180-degree hemispherical fisheye lens (Figure 16). Following the
same procedure as illuminance measurements, photos were taken in the laboratories on multiple days at
varying times of the day. Photos in the laboratories were taken at lab benches that researchers were likely
to be working at for extended periods of time instead of choosing locations on an arbitrary grid (Figure
17). This procedure was chosen due to the occupant-focused nature of the study. At desk spaces, photos
were taken from the perspective of the occupant as though they were sitting facing their computer and one
from the perspective of the occupant as though they were sitting at their desk but facing directly towards
the window. All photos were taken at an occupant’s seated eye height at 4 ft above the floor in the labs
and at the desks. In order to create the HDR image, 12 photos were taken at each instance at a range of
exposures. Entirely black (dark) or entirely white (bright) photos were discarded and the rest were
combined to create an HDR image (Figure 18). The HDR image was then analyzed using Evalglare
computer software to determine daylight glare probability (DGP). DGP values are defined as follows:
imperceptible = < 0.35, perceptible = 0.35-0.4, disturbing = 0.4-0.45, intolerable = > 0.45 (Jakubiec and
Reinhart 2012).

40

Figure 16. (Left) Camera for HDR image capture.

Figure 17. NE Lab (left) and S Lab (right) with locations/directions of HDR image capture marked by the blue arrow.
The numbers indicate the distance of each measurement from the façade.

Figure 18. Example HDR image taken in the S Lab at 12 p.m. on November 20. The DGP as analyzed by Evalglare is
0.258 (imperceptible).

41

4.1.4 Spectral Power Distribution

The SPD was measured using an Ocean Optics Spectrometer (Figure 19). The spectrometer connects to
the computer and measures the light spectrum through a blue tube with a light sensor on the end. The
output of the spectrometer is a distribution of the wavelengths of the light that is hitting the sensor at the
end of the tube. The distribution is measured in irradiance (W/m
2
) and wavelength is measured in
nanometers. In the NE Lab, lighting spectrum was measured in the center aisle at 5, 15, 25, and 35 ft from
the east façade (Figure 20). In the S Lab, lighting spectrum was measured at the same location as the HDR
images were captured (Figure 20). These measurement locations were chosen based on the configurations
of the labs. At all of the measurement locations in both labs, the lighting spectrum was recorded in all four
cardinal directions. At desk spaces, lighting spectrum was measured simultaneous to HDR image capture:
one measurement was recorded as though the occupant were sitting at their desk facing the computer and
a second measurement was recorded as though the occupant were sitting at their desk facing the façade.
The spectrometer’s sensor was mounted to the camera lens at a height of 4 ft above the floor for all lab
and desk measurements.

Figure 19. Ocean Optics Spectrometer. The spectrometer is the blue tube mounted on the camera lens and the black
box below the camera that the tube is connected to. At the end of the tube is a light sensor which, as mounted,
captures vertical light.

42

Figure 20. NE Lab (left) and S Lab (right) with locations and directions of spectrometer measurements indicated in
orange. The lighting spectrum was recorded at each location in the N, S, E, and W direction. The numbers indicate
the distance of the measurement from the façade.

The spectrometer outputs a graph of the light spectrum with wavelength on the x-axis and irradiance on
the y-axis as shown in Figure 21. The melatonin suppression triggered by this spectrum can then be
determined using a model of phototransduction created by scientists at the Lighting Research Center at
Rensselaer Polytechnic Institute (M. S. Rea, et al. 2005). The melatonin suppression for the graph in
Figure 21 is 59.3%. The upper limit for melatonin suppression is around 70%.

Figure 21. Sample light spectrum. A lot of daylight mixed with fluorescent lighting as evidenced by the spikes in
wavelength around 550 and 600nm.

43

4.2 Occupant Survey

An occupant survey was conducted to complement the physical data collection with subjective feedback
of the occupants in their personal workspaces. Fifteen building occupants were recruited to participate in
the survey on a voluntary basis. Those who participated had workspaces that were spread out on all three
floors and were a mixture of graduate students/researchers, administration, and IT (information
technology) staff. The survey consisted of two parts: a continuous two week survey and a one-time follow-
up survey.

4.2.1 Occupant Mobile Gateway Survey

The Occupant Mobile Gateway (O.M.G.) is a smartphone application developed by Professors Kyle Konis
and Murali Annavaram at the University of Southern California. The application prompts users to
complete a brief survey at a specified interval (Figure 22). The survey and time interval can be specified
based on the needs of the study being conducted. For this study, the application prompted the user to
complete a one-question survey every 1.5 hours between 7 AM and 7 PM. The user is prompted with a
question which asks them “Please rate the amount of light from windows right now.” The response options
are (a) “TOO LOW! It bothers me!” (b) “LOW, but I am not bothered,” (c) “Just right,” (d) “HIGH, but I
am not bothered,” and (e) “TOO HIGH! It bothers me!”

Figure 22. O.M.G. “light from windows” question dialog and response.

Simultaneous to the user submitting their response, the smartphone device records the temperature for the
first question and the illuminance for the second question. The temperature is measured via a thermal
sensor that plugs into the device’s audio port. The thermal sensor has been calibrated to account for the
temperature increase at the sensor due to heat generated by the smartphone. The illuminance is measured

44

by the built-in light sensor in the smartphone. In addition to recording these two measurements when a
survey response is recorded, the device was also set to collect data continuously throughout the two-week
study at an interval of 1.5 hours. All responses are sent to a spreadsheet which records the response,
illuminance, time and date of response, and on which survey device the response was recorded.

Each of the 15 occupants who volunteered to participate was provided a research-funded smartphone for
the two-week duration of the study. They were instructed on how to use the device and how to respond to
the survey prompts. They were told to keep the phone face-up on their desks while they were working.
For those participants who also work in laboratories, they were told that they could take the phones with
them but that they were not obligated to and could leave them on their desks instead. Through Wi-Fi
mapping, the location of the occupant within the building at the time of their response can be determined.
Therefore, for the researchers, it can be determined whether they were at their desk or in a laboratory when
the response was recorded.

4.2.2 Overview Follow-Up Survey

Following the O.M.G. survey, the participants completed a one-time questionnaire. The questionnaire
asked about general satisfaction with daylighting and glare in the building, satisfaction with views, and
the frequency with which they adjust interior shades and electric lighting. The full nine-question survey
can be found in the appendix.

For the purposes of this study, a successful rate of occupant satisfaction is defined as ≥ 80%.

4.3 Chapter Summary

This chapter presented the methodology of the post-occupancy evaluation of the Jorgensen Lab. The
methodology consisted of three major parts: (1) physical data collection, (2) occupant survey, and (3)
daylighting simulation. Physical data collection occurred in laboratories and at occupant desk spaces and
included documentation of interior shade positions, measurements of horizontal illuminance, HDR image
capture for glare analysis, and measurement of lighting spectrum via spectrometry.

45

5 RESULTS

The study encompassed two of the largest, daylit laboratories on the top floor and fourteen occupant
workstations. The laboratories are referred to as the Northeast (NE) Lab and South (S) Lab. As the
methodology for data collection and analysis was different between the labs and offices due to the
differences in the type of spaces, the results section is split into laboratory and office data collection.

5.1 Laboratory Results

This section details interior shade positioning, illuminance, glare, and spectrometry for the laboratories.

5.1.1 Interior Shade Positioning

The positioning of the interior shades was recorded via observation during each visit to the building. The
goal was to document the changes in shade position over time; however, upon each visit to the building
the shades were consistently observed to be in the same position.

A diagram of the interior shade positions in the NE Lab are shown in Figure 23. Located on the corner of
the building, this lab has two glazed exterior walls (east and north). The blue panels represent clear glazing
(VT 50%) with complete view to the outdoors, the light blue/white panels represent translucent panels
with 12% VT, and the dark gray shading represents the interior shades (openness factor 5%) as they were
positioned throughout the duration of the study. Overall, the east façade is approximately 74% clear
glazing and 26% translucent glazing. Approximately 66% of the total glazing was occluded by shades
with 69% of the clear glazing and 80% of the translucent glazing occluded. The north façade is
approximately 69% clear glazing and 31% translucent glazing overall. Approximately 36% of the glazing
is occluded by shades with 57% of the clear glazing and 35% of the translucent glazing occluded. A
summary of these results is presented in Table 1. The shades on the north façade are extremely
difficult/impossible to adjust as they are blocked by lab benches with shelves full of fragile glass lab
equipment. The southern-most shade on the east façade was broken and inoperable. In the diagram, the
only clear glazing panels that are 100% un-occluded are those that would have been covered by the
southern-most shade.

Table 1. Façade occlusion by interior shades in the NE Lab.
Percent of Total Façade Percent Occluded
EAST
Clear 74% 69%
Translucent 26% 31%
Total 66%
NORTH
Clear 69% 57%
Translucent 31% 35%
Total 36%

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Figure 23. Interior shade positioning for the east (top) and north (bottom) façades in the NE Lab. The blue panels
represent clear glazing with complete view to the outdoors, the light blue/white panels represent translucent panels,
and the dark gray shading represents the interior shades as they were positioned throughout the duration of the
study. The east façade is 66% occluded by shades and the north façade is 36% occluded.

The S Lab has one glazed exterior façade. A diagram of the interior shade positions for this façade are
shown in Figure 24. Overall, the façade is 50% clear glazing and 50% translucent glazing. Approximately
28% of the glazing is occluded by shades with 44% of the clear glazing and 13% of the translucent glazing
occluded. These results are summarized in Table 2. Similar to the north façade of the NE Lab, there were
shades on this façade that were extremely difficult to adjust due to being blocked by lab bench shelves
filled with equipment. The shade on the western-most end of the façade (the only shade pulled 100% of
the way down) was permanently stuck in that position.

Table 2. Façade occlusion by interior shades in the S Lab.
Percent of Total Façade Percent Occluded
SOUTH
Clear 50% 44%
Translucent 50% 13%
Total 28%

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Figure 24. Interior shade positioning for the south façade in the S Lab. The blue panels represent clear glazing with
complete view to the outdoors, the light blue/white panels represent translucent panels, and the dark gray shading
represents the interior shades as they were positioned throughout the duration of the study. The façade is 28%
occluded by shades.

5.1.2 Illuminance

“Point in time” global horizontal illuminance measurements were taken periodically over the course of
the study in the NE and S Labs using an illuminance meter. All of the measurements were taken with the
electric overhead lighting turned on; therefore, measurements were also taken after dark to record the
illuminance of only the electric lighting. The electric lighting illuminance was then subtracted from the
overall illuminance to determine the illuminance from the daylight only. This calculation was possible
because it was documented that the same overhead lights were turned on in the labs during each visit
during the day and the night, and the lights did not dim during the day.

Figure 25 shows a comparison of the illuminance distribution at 3 ft off the floor over a grid spaced at 10
ft by 10 ft. The measurements were taken in the NE Lab with and without electric lights on October 30, a
clear day, at 9:30 a.m. The diagram on the left is the lab with only daylight and the diagram on the right
is the lab with both daylight and electric lighting. The diagrams of shade positions from the previous
section are included for reference. Illuminance was measured at each of the locations marked by a color-
coded circle. All except for the darkest gray circles indicate locations in which the illuminance was above
100 lux, the threshold for which the LEED v2009 daylighting credit requires at least 75% of the space to
exceed. The orange and yellow circles indicate locations in which the measured illuminance exceeded 300
lux, the minimum threshold for illuminance specified by sDA and LEED v4. The percentage of floor area
exceeding 100 lux from daylight was 65% and 300 lux was 45%. On the daylight only diagram, the
percentages indicate the amount of the total light at each location that was daylight. Unless otherwise
stated the remainder of the diagrams will show only the illuminance from daylight.

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Figure 25. NE Lab illuminance map comparison with (right) and without (left) electric lighting at 9:30 a.m. on
October 30. The percentage indicates the amount of the total light that was from sunlight.

Figure 26 shows a comparison of daylight illuminance in the NE Lab with the shades positioned as used
and with the shades up on October 30 at 9:30 a.m. Only the shades on the east façade were adjusted for
the comparison as it is the only façade that receives direct sunlight in this lab. With the shades positioned
as used, the percent of floor area above 100 lux was 65% and 300 lux was 45% (this is the same data as
the daylight diagram from Figure 25). With the shades up on the east façade, the percent of the floor area
above 100 lux was 75% and 300 lux was 60%.

Figure 26. NE Lab illuminance map comparison with shades as used (left) and with shades up (right) on the east
façade at 9:30 a.m. on October 30.

49

Figure 27 shows a comparison of daylight illuminance in the NE Lab on November 13 at 10 a.m., 12 p.m.,
and 2 p.m. The percent of floor area above 100 lux was 80% at 10 a.m., 60% at 12 p.m., and 60% at 2
p.m. The percent of floor area above 300 lux was 50% at 10 a.m., 35% at 12 p.m., and 15% at 2 p.m.

Figure 27. NE Lab illuminance map comparison of morning (left), noon (center), and afternoon (right) on November
13.

Figure 28 shows a comparison of the illuminance in the S Lab with and without electric lights on
November 3 at 11:30 a.m. The diagram on the left is the lab with only daylight and the diagram on the
right is the lab with both daylight and electric lighting. On the daylight only diagram, the percentages
indicate the amount of the total light at each location that was daylight. The percent of the floor area that
daylight exceeds 100 lux was 83% and 300 lux was 58%.

50

Figure 28. S Lab illuminance map comparison with (right) and without (left) electric lighting at 11:30 a.m. on
November 3. The percentage indicates the amount of the total light that was from sunlight.

Figure 29 shows a comparison of the daylight illuminance in the S Lab on November 10 at 9:30 a.m.,
11:30 a.m., and 1:30 p.m. The percent of the floor area above 100 lux was 83% at 9:30 a.m., 75% at 11:30
a.m., and 58% at 1:30 p.m. The percent of the floor area above 300 lux was 75% at 9:30 a.m., 50% at
11:30 a.m., and 42% at 1:30 p.m.

Figure 29. S Lab illuminance map comparing morning (left), noon (center), and afternoon (right) on November 10.

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Figure 30 shows a comparison of the daylight illuminance in the S Lab on November 20 at 9:45 a.m.,
11:45 a.m., and 1:45 p.m. The percent of the floor area above 100 lux was 75% at 9:45 a.m., 75% at 11:45
a.m., and 50% at 1:45 p.m. The percent of the floor area above 300 lux was 42% at 9:45 a.m., 58% at
11:45 a.m., and 42% at 1:45 p.m. The illuminance results are summarized in Table 3 and Table 4.

Figure 30. S Lab illuminance map comparing morning (left), noon (center), and afternoon (right) on November 20.

Table 3. Summary of horizontal illuminance results in the NE Lab measured in terms of percent of floor area above
100 and 300 lux.
Date Time
Floor area above…
Notes
100 lux 300 lux
10/30/2016 9:30 AM
65% 45% shades down
75% 60% shades up
11/3/2016 9:30 AM 50% 35%
11/13/2016
10:00 AM 80% 50%
12:00 PM 60% 35%
2:00 PM 60% 15%

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Table 4. Summary of horizontal illuminance results in the S Lab measured in terms of percent of floor are above 100
and 300 lux.
Date Time
Floor area above…
100 lux 300 lux
11/3/2016 11:30 AM 83% 58%
11/6/2016 11:30 AM 75% 67%
11/10/2016
9:30 AM 83% 75%
11:30 AM 75% 50%
1:30 PM 58% 42%
11/20/2016
9:45 AM 75% 42%
11:45 AM 75% 58%
1:45 PM 50% 42%

5.1.3 Glare

Glare was measured using the Daylight Glare Probability (DGP) metric as calculated by Evalglare, and
the values are defined as follows: imperceptible = < 0.35, perceptible = 0.35-0.4, disturbing = 0.4-0.45,
intolerable = > 0.45 (Jakubiec and Reinhart 2012). In the NE Lab, glare was evaluated at four typical lab
station locations in the center aisle of the laboratory as indicated on the floor plan in Figure 31. The
diagram (Figure 31) shows the floor plan of the NE Lab with the location and direction of image capture
marked by blue arrows. The distances next to each arrow are measured from the east façade. An example
image for each of the locations is shown to give context to the DGP values. The DGP values collected for
the NE Lab are presented in Table 5. Each of the “camera orientation” columns corresponds to the blue
arrows on the floor plan in Figure 31. None of the DGP values measured in the NE Lab exceed 0.26,
meaning they are all in the range of “imperceptible” glare.

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Figure 31. NE Lab diagram of image capture for glare analysis. The blue arrows indicate the location of the camera
(measured from the east façade) and the direction it was facing. An example image of each of the four locations is
provided for context of what the camera was capturing.

Table 5. Daylight Glare Probability measurements in the NE Lab (unless otherwise noted, the shades were positioned
as used and the sky was clear).
DAYLIGHT GLARE PROBABILITY in the NE LAB
Date Time
Camera Orientation
Notes
25 ft, facing N 25ft, facing S 10 ft, facing S 6 ft, facing N
27-Oct 10:30 AM 0.215 0.091 0.154 -
30-Oct 10:30 AM
0.110 0.251 0.212 0.165 shades down
0.154 0.223 0.217 0.192 shades up
3-Nov 10:30 AM
0.183 0.216 0.098 0.14 clouds
0.217 0.235 0.111 0.18 clear sky
13-Nov
10:00 AM 0.118 0.227 0.223 0.158
12:00 PM - 0.237 - 0.204
2:00 PM 0.205 0.228 - 0.207

On October 30 at 10:30 a.m., a comparison of DGP with shades as used and shades up was collected. The
DGP at 6ft from the façade facing south increased by 0.027 when the shades were rolled up, and the DGP
at 25ft facing north increased by 0.044. The DGP at 10ft facing south increased very little (0.005), and the
DGP at 25ft facing south actually decreased by 0.028. These results do not indicate a strong trend, likely
due to the fact that for all measurements (except for the ones at 6 ft from the façade) direct sunlight from
the façade is only minimally visible from these locations.

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On November 3 at 10:30 a.m., a comparison of DGP with cloudy and clear skies was collected. The DGP
for all four measurement locations increased in clear skies when compared to the cloudy sky condition.
The increases were 0.04 at 6ft facing north, 0.013 at 10ft facing south, 0.019 at 25ft facing south, and
0.034 at 25ft facing north.

On November 13, a comparison of DGP at 10 a.m., 12 p.m., and 2 p.m. was collected. A few of the data
points were not able to be measured due to researchers actively conducting lab experiments at the time of
data collection. At 6ft from the façade facing north the DGP increased as the day progressed with the
largest increase between 10 a.m. and 12 p.m. of 0.046. At 25ft facing south, the DGP increased slightly
and then decreased again from 10 a.m. to 12 p.m. to 2 p.m. Overall, the DGP in the NE Lab for all times
of day, shade positions, and sky conditions, was fairly low and did not change dramatically as the different
variables changed.

In the S Lab, glare was evaluated at five typical lab stations throughout the lab. These locations are
indicated on the floor plan in Figure 32 by blue arrows which indicate the location and direction that the
image was captured. The distances next to each of the arrows is measured from the south façade. An
example is provided for each of the five locations to give context for the environment being captured for
the DGP determination. All of the DGP values collected for the S Lab are presented in Table 6, and each
column corresponds to one of the five locations. The three cells highlighted in light grey are in the range
of “perceptible glare” (DGP = 0.35-0.4) and the dark grey cells with red font exceed the threshold of
“intolerable” glare (DGP > 0.45). Whereas in the NE Lab none of the DGP values exceeded 0.26, some
of the values in the S Lab, particularly at 3ft facing south, reach up to 0.6.

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Figure 32. S Lab diagram of image capture for glare analysis. The blue arrows indicate the location of the camera
(distances measured from the south façade) and the direction it was facing. An example image of each of the four
locations is provided for context of what the camera was capturing.

Table 6. Daylight Glare Probability measurements in the S Lab.
Date Time
Camera Orientation
5ft, facing W 22ft, facing E 25ft, facing W 11ft, facing E 3ft, facing S
10/27/2015 11:30 PM 0.205 - - 0.137 0.321
10/30/2015 12:00 PM 0.16 - - 0.268 0.457
11/3/2015 12:30 PM 0.182 - - 0.297 0.492
11/6/2015 11:30 AM 0.187 - - 0.268 0.496
11/10/2015
11:30 AM 0.235 0.178 0.171 0.249 0.518
1:30 PM 0.192 0.115 0.155 0.227 0.366
11/20/2015
10:00 AM 0.396 - 0.222 0.217 0.248
12:00 PM 0.235 0.322 0.206 0.264 0.625
2:00 PM 0.108 0.202 0.199 0.223 0.358

Overall, the DGP measurements for all except for 3ft facing south are in the range of “imperceptible”
glare (DGP < 0.35). The values at 3ft facing south however are, predictably, much higher as the lab station
is only 3 ft away from the façade and facing directly toward the window into direct sunlight. The lab bench

56

shelves provide some shelter for the lab work station. The DGP values measured at this location ranged
from 0.321-0.625 around noon between the dates 10/27 and 11/20.

On November 10, a comparison of DGP at 11:30 a.m. and 1:30 p.m. was measured. For all five
measurement locations, the DGP was higher at 11:30 a.m. than at 1:30 p.m. The difference are 0.043 at
5ft facing west, 0.063 at 22ft facing east, 0.016 at 25ft facing west, 0.022 at 11ft facing east, and the largest
difference of 0.152 at 3ft facing south.

On November 20, a comparison of DGP was made at 10:00 a.m., 12:00 p.m., and 2:00 p.m. Similar to the
November 10 data, all of the afternoon DGP values are lower than the values at noon. The morning (10:00
a.m.) values, however are not consistently lower as might be expected; the values are higher in the morning
at 5ft facing west and 25 ft facing west. Again, the largest difference between values is at 3ft facing south.
The DGP at 12:00 p.m. is 0.377 higher than the DGP at 10:00 a.m. and 0.267 higher than the DGP at 2:00
p.m.

5.1.4 Spectral Power Distribution

A spectrometer was used to measure the spectral power distribution (SPD) in a number of locations and
orientations in the NE and S Labs. From the data recorded by the spectrometer, the light spectrum was
graphed, and the melatonin suppression was calculated as a percent.

The diagram in Figure 33 shows the locations in which the spectral power distribution was measured in
the NE Lab. Measurements were taken in the middle aisle at varying distances from the east façade. At
each of the locations (marked by purple arrows) the light spectrum was recorded in all four cardinal
directions (N, S, E, W). The photos to the left of the floor plan are views of the center aisle, the center
photo taken from the back of the lab facing the east façade, and the right photo taken from in front of the
façade facing the back of the lab (Figure 33).

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Figure 33. (Left) NE Lab floor plan with location and direction of spectrometry measurements. The distance are
measured from the east façade. (Center) View of center aisle looking toward the east façade. (Right) View of center
aisle looking towards the west wall.

Spectrometry measurements were recorded in the NE Lab on November 13 at 10 a.m., 12 p.m., and 2 p.m.
The spectral power distributions for the measurements taken at 10 a.m. are shown in the diagrams in
Figure 34-Figure 37. Each diagram displays the spectrums in the north, south, east, and west directions as
indicated by the directional arrows inside the box in the center of the diagram. The box is a simplified
representation of the lab with the dotted lines and solid lines indicating the façade faces and the interior
walls, respectively, that define the room. The number in the center of the box corresponds to the location
on the floor plan (Figure 33) from which the data was recorded (for example, the graphs in Figure 34 were
recorded at 5 ft from the façade). In the upper left corner of each of the individual graphs is the percent
that melatonin would be suppressed in that lighting environment. The numbers are green when melatonin
suppression is above 20% and red when it is below 20% (the rationale for using a cutoff of 20% is
presented in the methodology in Chapter 4).

A B C D

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Figure 34. Lighting spectrum in the NE Lab, 5 ft from the façade, recorded on November 13 at 10 a.m. Percent
melatonin suppression is shown in the upper left corner of each graph.

Figure 35. Lighting spectrum in the NE Lab, 15 ft from the façade, recorded on November 13 at 10 a.m. Percent
melatonin suppression is shown in the upper left corner of each graph.

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Figure 36. Lighting spectrum in the NE Lab, 25 ft from the façade, recorded on November 13 at 10 a.m. Percent
melatonin suppression is shown in the upper left corner of each graph.

Figure 37. Lighting spectrum in the NE Lab, 25 ft from the façade, recorded on November 13 at 10 a.m. Percent
melatonin suppression is shown in the upper left corner of each graph.

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At 10 a.m., the only value below 20% was at 15 ft facing north, which yielded a value of 15% melatonin
suppression. A summary of all of the spectrometry data collected on November 13 in the NE Lab is
presented in Table 7. Each row is a different time of day and each column is the distance from the east
façade. Each cell contains the percent melatonin suppression determined for each direction (N, S, E, W)
with an arrow pointing north for orientation. The only location below 20% melatonin suppression at all
three times of data collection was at 15 ft facing north.

Table 7. Summary of spectrometry data collection in the NE Lab. The numbers shaded grey are percent melatonin
suppression. Each block is one location and time, and the arrow points north.
A B C D
13-Nov
10:00 AM
54 34 15 52
21 ↑ 44 41 → 49 46 → 55 42 → 67
40 26 29 53
12:00 PM
55 38 12 48
25 ↑ 46 45 → 50 48 → 53 40 → 67
42 39 27 44
2:00 PM
52 33 11 49
20 ↑ 46 42 → 47 45 → 52 40 → 66
39 39 26 41

In the S Lab, spectrometry measurements were recorded at the locations indicated on the floor plan
diagram in
Figure 38. The measurement locations are marked by purple arrows in the same way it was marked in the
NE Lab. Due to a differing configuration from the NE Lab, measurements were taken at typical
workstations in each of three aisles. The photos to the right of the floor plan show views of the lab looking
towards the south façade and the north interior wall in each of the aisles.

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Figure 38. (Left) S Lab floor plan with location and direction of spectrometry measurements. The distance are
measured from the south façade. (Right) Photos of the S Lab in each of the three aisles. The top row of photos looks
towards the back of the lab and the bottom row looks towards the south façade.

Spectrometry measurements were recorded in the S Lab on November 20 at 10 a.m., 12 p.m., and 2 p.m.
The results for the S Lab are presented here in the same way that the NE Lab results were presented.
Figure 39-Figure 43 show the spectral power distributions recorded at each location at 10 a.m.

Figure 39. Lighting spectrum in the S Lab, 5 ft from the façade, recorded on November 20 at 10 a.m. Percent
melatonin suppression is shown in the upper left corner of each graph.
A
B
C
D
E

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Figure 40. Lighting spectrum in the S Lab, 22 ft from the façade, recorded on November 20 at 10 a.m. Percent
melatonin suppression is shown in the upper left corner of each graph.

Figure 41. Lighting spectrum in the S Lab, 11 ft from the façade, recorded on November 20 at 10 a.m. Percent
melatonin suppression is shown in the upper left corner of each graph.

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Figure 42. Lighting spectrum in the S Lab, 25 ft from the façade, recorded on November 20 at 10 a.m. Percent
melatonin suppression is shown in the upper left corner of each graph.

Figure 43. Lighting spectrum in the S Lab, 3 ft from the façade, recorded on November 20 at 10 a.m. Percent
melatonin suppression is shown in the upper left corner of each graph.

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At 10 a.m., the only value below 20% was at 22 ft in the west-most aisle facing north. This location yielded
a melatonin suppression of 17%. A summary of the spectrometry data collected in the S Lab on November
20 is presented in Table 8. The location at 22 ft facing north remained below 20% at each time of data
collection, yielding a melatonin suppression of 15% at noon and 7% at 2 p.m. The only other instance
below 20% was at 5 ft in the west-most aisle facing north at 2 p.m. Otherwise, the largest values occurred,
predictably, at the locations closest to the façade when the spectrometer was oriented south.

Table 8. Summary of spectrometry data collection in the S Lab. The numbers shaded grey are percent melatonin
suppression. Each block is one location and time, and the arrow points north.
A B C D E
20-Nov
10:00 AM
44 17 54 44 58
53 ↓ 65 30 ↓ 40 67 ↓ 57 32 ↓ 33 63 ↓ 60
69 49 71 61 65
12:00 PM
39 15 50 43 70
46 ↓ 59 29 ↓ 38 57 ↓ 60 29 ↓ 31 66 ↓ 72
71 45 70 57 72
2:00 PM
12 7 39 41 56
20 ↓ 42 23 → 38 47 ↓ 45 25 ↓ 27 58 ↓ 68
53 27 66 50 68

5.2 Office and O.M.G. Survey Results

The data collection in office workspaces consisted of 13 participants located throughout all three floors of
the building and included both administrators and researchers. Each of the participants was set-up with an
O.M.G. survey device for two weeks and glare and lighting spectrum were measured during one occasion
at each of the participants’ desk spaces. The diagram in Figure 44 shows the location of each of the
participants’ workspaces on the floor plan with an identifying number (2-13, 16) based on the identifying
number of the O.M.G. device which they were issued. This section details the glare, spectrometry, and
O.M.G. survey results for the office spaces.

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Figure 44. Location of participant workstations in the Jorgensen Lab labeled with identifying number.

5.2.1 Glare

Photos for glare analysis were taken at each desk with one photo facing towards the occupant’s computer
and a second photo taken in the same location but facing towards the nearest façade. Figure 45 shows
sample HDR images from Desk 6 comparing the DGP when shades are down versus when they are up.
As expected, the DGP increases facing both the desk and the façade when the shades are pulled up.

Figure 45. HDR images taken at Desk 6 for comparison of DGP with the shades up and down. (Left) Facing towards
the occupant’s desk. (Right) Facing towards the nearest façade from the occupant’s desk.

Presented in Table 9 are the DGP results at each of the participant’s desks. The values are shown facing
the façade and facing the desk/computer. The cardinal direction is included for which the camera was
facing in order to take the measurement and the table is organized firstly by the direction of the nearest
façade. Only one value exceeded the “imperceptible” glare threshold of 0.35 DGP. The location that
exceeded 0.35 is at Desk 2 facing the façade. This desk is located on the north side of the second floor,
directly adjacent to the façade. Although the north façade does not receive direct sunlight, the workstation
is in very close proximity to the façade which could have possibly been the reason for the DGP value as
the shades were not pulled down.

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Table 9. Daylight Glare Probability as measured at occupant desks. Numbers in red indicate DGP that exceeds 0.3.
Desk # Date Time
Daylight Glare Probability
Floor
Distance
from façade
Shade
position
Facing façade Facing desk
3 17-Nov 10:20 AM E 0.077 NW 0.236 1st 8 ft down
8 20-Nov 9:30 AM E 0.248 SE 0.238 1st 5 ft down
7 17-Nov 10:15 AM E 0.205 N 0.128 2nd 2 ft down
12 17-Nov 11:00 AM S 0.22 E 0.206 2nd 3 ft down
16 17-Nov 11:10 AM S 0.238 W 0.219 2nd 6 ft down
11 17-Nov 10:00 AM S 0.236 E 0.337 2nd 3 ft down
5 17-Nov 10:30 AM S 0.173 W 0.152 G 8 ft down
5 17-Nov 10:35 AM S 0.257 W 0.17 G 8 ft up
6 17-Nov 10:30 AM S 0.12 W 0.093 G 2 ft down
6 17-Nov 10:35 AM S 0.249 W 0.123 G 2 ft up
10 17-Nov 10:45 AM S 0.113 E 0.012 G 8 ft down
9 17-Nov 1:40 PM S - E 0.18 G 20 ft -
2 17-Nov 11:20 AM N 0.369 W 0.207 2nd 2 ft up
4 17-Nov 11:40 AM N 0.294 W 0.03 1st 5 ft up
13 17-Nov 11:30 AM N 0.254 W 0.045 1st 10 ft up

5.2.2 Spectral Power Distribution

Measurements of spectral power distribution were taken in the exact same manner as the glare
measurements, therefore each light spectrum has a corresponding HDR image. A few samples are shown
in the following figures. Figure 46 shows the spectral power distributions and HDR images taken at Desk
4 located on the first floor adjacent to the north façade. This location yielded an insufficient melatonin
suppression of 4% when facing the desk and a barely passing 21% when facing the façade. Compared to
all of the other office spaces in the building, this office has a very small amount of window surface area,
a stairway blocks daylight from the outside, and a piece of cardboard has been placed on the inside of the
window by the occupants, further reducing daylight penetration in the room.

Figure 46. Lighting spectrums and corresponding HDR images for Desk 4. (Left) Facing the desk. (Right) Facing the
north façade.

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Figure 47 shows the lighting spectrum and HDR images taken at Desk 11 located on the southeast corner
of the second floor. This location yielded very high melatonin suppression values nearing saturation with
68% facing the south façade and 62% facing the desk. Daylight is not impeded by any overhangs or trees
at this location, therefore direct sunlight can easily reach the façade in the morning hours when the
measurement was recorded. It is also of note that the shades are pulled down at this location.

Figure 47. Lighting spectrums and corresponding HDR images for Desk 11. (Left) Facing the south façade. (Right)
Facing the desk.

Figure 48 shows the lighting spectrums and HDR images taken at Desk 6 located on the south side of the
basement level. One set of measurements was recorded with the shades pulled down as they are used by
the occupants and a second set of measurements was recorded with the shades rolled up. With the shades
pulled down, the melatonin suppression was 28% facing the façade and 18% facing the desk. When the
shades were pulled up, the value increased to 58% facing the façade and decreased to 15% facing the desk.
The position of the shades had very little impact in changing the melatonin suppression value facing the
desk, for which both values are below the recommended value. However, the value when facing the façade
did increase a significant amount.

Figure 48. Lighting spectrums and corresponding HDR images for Desk 6 with shades up and shades down. (Left)
Facing the south façade. (Right) Facing the desk. (Top) Shades down. (Bottom) Shades up.

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Presented in Table 10 are the spectrometry results for melatonin suppression at each of the occupant
workstations. The values are presented in the same format as the DGP. A few of the values fall below
sufficient melatonin suppression of 20%, indicated in red in the table. These values mainly occur facing
toward the desk and by turning towards the façade the melatonin suppression increases to sufficient levels
for circadian function. One insufficient value was found in the orientation facing the façade. In this office,
all of the shades were pulled down, a large column blocks a portion of the window on the inside, and trees
shade the façade from the outside. All of the electric lighting is turned on including a bright task light
above the computer which might explain the higher value for melatonin suppression when facing the desk.

Table 10. Melatonin suppression as measured at occupant desks. Numbers in red indicate values less than 20%.
Desk # Date Time
Melatonin Suppression (%)
Floor
Distance from
façade
Shade
position
Facing façade Facing desk
3 17-Nov 10:20 AM E 19.2 NW 35.3 1st 8 ft down
8 20-Nov 9:30 AM E 60.2 SE 50.7 1st 5 ft down
7 17-Nov 10:15 AM E 53 N 32 2nd 2 ft down
12 17-Nov 11:00 AM S 59.8 E 46.4 2nd 3 ft down
16 17-Nov 11:10 AM S 66.7 W 49 2nd 6 ft down
11 17-Nov 10:00 AM S 67.8 E 61.7 2nd 3 ft down
5 17-Nov 10:30 AM S
39.7
W
27.8
G 8 ft
down
64 34.9 up
6 17-Nov 10:30 AM S
28.9
W
17.7
G 2 ft
down
57.8 14.9 up
10 17-Nov 10:45 AM S
28.9
E
0
G 8 ft
down
50.9 4.6 up
9 17-Nov 1:40 PM S - E 31.2 G 20 ft -
2 17-Nov 11:20 AM N 69.9 W 55.6 2nd 2 ft up
4 17-Nov 11:40 AM N 20.5 W 4.4 1st 5 ft up
13 17-Nov 11:30 AM N 40.4 W 7.8 1st 10 ft up

5.2.3 O.M.G. Survey Results

The Occupant Mobile Gateway survey was completed by 15 occupants for a time period of two weeks.
The survey asked one question every one and a half hours about the occupant’s satisfaction with light
from windows while simultaneously recording the illuminance level. The overall results are shown in a
boxplot in Figure 49. The most common response was (3) “neutral” with 107 out of a total of 214
responses. The second most frequent response was (2) “low but I am not bothered” with 89 responses.
The rest of the response options were recorded only a few times: (1) “too low it bothers me” had 12
responses, (4) “high but I am not bothered” had 5 responses, and (5) “too high it bothers me” had only

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one response. Based on the boxplot, the average illuminance was around 300-400 lux for responses (2),
(3), and (4). The average illuminance for response (1) was around 200 lux. Response (5) had only one
response with an illuminance of 50 lux, which is likely an error. It is possible that the survey device was
placed in a shaded location, or that the response itself was incorrect. Either way, response (5) is not
included in the analysis.

Figure 50 breaks the responses down into four separate histograms, one for each response, binned by
illuminance. The fifth survey response “too bright, it bothers me” is not shown because there was only
one instance of this response recorded in the study. The histograms show the number of each response
option that was recorded in each of the illuminance ranges set at 100 lux intervals. The first response
option (1) “too low, it bothers me” indicates that the occupant felt that there was insufficient daylight. All
instances of this response occurred below 400 lux and there were 12 instances of this response. The second
response option (2) “low but I am not bothered” indicates that the occupant would preferably like more
daylight but that it is not causing them discomfort. All but one of these responses was above 600 lux and
most were below 500 lux (86 out of 89 total instances). The third response option (3) “neutral” indicates
that the occupant is perfectly content with the amount of daylight. This was the most common response.
The fourth response (4) “high but I am not bothered” was recorded less than 10 times and each instance
was recorded at less than 500 lux. This is unexpected but may due to the placement of the survey device
on the occupant’s workspace. It is possible that the device receiving less daylight/light than the rest of the
room.

Note that the illuminance measures both daylight and electric lighting, therefore the question is gauging
occupant’s perception of daylight sufficiency and not actual daylight.

6
Figure 49. Boxplot of O.M.G. responses. (1) Too low it bothers me, (2) low but I am not bothered, (3) neutral, (4) high
but I am not bothered, (5) too high it bothers me.

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Figure 50. O.M.G. survey results displaying responses to satisfaction with daylight. Each histogram represents a
different response. (1) Response “too low, it bothers me” (2) Response “low but I am not bothered” (3) Response
“neutral” (4) Response “bright but I am not bothered” (5) Response “too bright, it bothers me” is not shown due to
only one instance of this response.

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5.3 Overall Occupant Survey

The overall occupant survey was distributed to everyone who works in the building and 20 responses were
collected. The survey consisted of seven major questions and the results are summarized in the following
figures. Figure 51 shows a bar chart of responses to the question “Overall, how satisfied are you with the
daylight at your desk workspace?” The most frequent response was “0 = very satisfied” followed by “-1
= mostly satisfied (prefer more daylight).”

Figure 51. Overall, how satisfied are you with the daylight at your desk workspace? -3 = very dissatisfied/too dim, 0 =
neutral, 3 = very dissatisfied/too bright

Figure 52 shows a bar chart of responses to the question “Overall, how satisfied are you with the daylight
in the lab you work most frequently” for which occupants were instructed to respond only if they worked
in one of the labs. The most frequent response was again “0 = very satisfied.” However, “-1 = mostly
satisfied (prefer more daylight)” and “-2 = dissatisfied (too little daylight)” also make up a significant
portion of the responses. No one responded that there was too much daylight in the labs.

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Figure 52. Overall, how satisfied are you with the daylight in the lab you work most frequently? (if you work in a lab)

Figure 53 shows a bar chart of responses to the question “Overall, how satisfied are you with views to the
outdoors at your desk workspace?” A majority of the responses fall between neutral and very satisfied.

Figure 53. Overall, how satisfied are you with views to the outdoors at your desk workspace?

Figure 54 shows a bar chart of responses to the question “Overall, how satisfied are you with your visual
connection to the outdoors when the roller shades were down?” A majority of respondents answered
“neutral” and more leaned toward dissatisfied than satisfied.

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Figure 54. Overall, how satisfied are you with your visual connection to the outdoors when the roller shades were
down in the lab?

Figure 55 shows a bar chart of responses to the question “How satisfied are you with glare in your
workspace(s)?” The most responses were recorded for “very satisfied” and very few respondents were
dissatisfied to any degree.

Figure 55. How satisfied are you with glare in your workspace(s)?

Figure 56 shows a bar chart of responses to the question “How often do you adjust the shades in your
workspace(s)?” Of the 19 responses recorded for this question, 14 responded that they never adjust the
shades in their workspaces. At most, occupants responded that they adjust the shades a few times per
month.

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Figure 56. How often do you adjust the shades in your workspace(s)?

Figure 57 shows a bar chart of responses to the question “”How often do you adjust the electric lighting
in your workspace(s)?” Though slightly less dramatic than the shade usage, the majority of occupants
responded that they never adjust the electric lighting. In the open plan desk workspaces (particularly the
student/researcher spaces on the second floor), overhead electric lighting was rarely used, and daylight
supplemented with task lighting seemed sufficient for the occupants. In the laboratories, however, the
same overhead lights seemed to always be turned on, and some of the lights did not respond to any of the
switches accessible by occupants. A conversation with one researcher in the S Lab revealed that he was
not sure how to turn on or off some of the overhead lights and always let them be, using task lights when
necessary.

Figure 57. How often do you adjust the electric lighting in your workspace(s)?

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5.4 Chapter Summary

This chapter presented the results from both the laboratories and office desk spaces in the Jorgensen Lab.
In the laboratories, the results were presented for shade positioning/usage, horizontal illuminance, glare,
and lighting spectrum. For the office spaces, the results were presented for glare, lighting spectrum, the
Occupant Mobile Gateway survey, and an overall occupant survey.

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6 DISCUSSION

This chapter discusses the implications of the results presented in the previous chapter and provides
lessons learned which can be used by designers to inform future daylighting design decisions. Recall from
the methodology chapter the study’s major research questions:

1) In regards to the façade, does the achieved visible light transmittance of the façade and components
in use match what was intended by the designer?
2) In regards to physical lighting properties:
a. Are the horizontal daylight illuminance levels intended by the designer being achieved?
b. Is there a high potential for glare discomfort?
c. Is the spectral power distribution from daylight sufficient for human health and well-being,
specifically in regards to melatonin suppression?
3) In regards to human comfort, what percentage of occupants are satisfied with daylight and views
in their workspaces?

Each of the results sections are discussed here in relation to these three questions.

6.1 Laboratory Results Discussion

6.1.1 Interior Shade Positioning

As mentioned previously, the goal was to document the change in the shade positions over time in order
to determine how much of the façade was shaded and how often. However, it was found that the shades
in the laboratories were never adjusted and remained in the same positions for the duration of the study.
Due to this, the variable of time is eliminated and the only factor remaining is how much of the façade is
shaded. This finding is particularly relevant because, as mentioned in Chapter 2, the spatial daylight
autonomy (sDA) calculation assumes “active” shade usage by occupants, specifically the metric assumes
that shades will be lower when illuminance exceeds 1000 lux and will be raised again when illuminance
falls below 1000 lux (Illuminating Engineering Society 2013). The newest version of LEED (v4) also uses
the sDA metric and this assumption.

The first research question asks how the achieved visible light transmittance (VLT) of the façade in use
compares to that which was designed/constructed. In order to answer this question, the intended visible
transmittance of the façade must be defined. It is assumed that the intent of the designer was for the full
use of the glazing, meaning that ideally none of the shades would be closed if not necessary, with necessary
meaning to block glare. The intended VLT is 50% for the clear glazing and 12% for the translucent
glazing.

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For the east façade in the NE Lab, the only time of day in which lowering the shades is necessary would
be in the morning when the façade receives direct sunlight. Observation has shown, however, that this
pattern of usage is not the case and that many of the shades are lowered and remain in one position
constantly. With 69% of the clear glazing shaded, the average VLT for the east façade in the NE Lab is
reduced to 17%. The translucent glazing, which was 80% shaded, is reduced to an average VLT of 3%.

The north façade in the NE Lab should never require shade usage because the north side of the building
will never receive direct sunlight. Many of the shades are pulled down and left there however. With 57%
of the clear glazing shaded, the average VLT is reduced to 23%. The translucent glazing, which was 35%
shaded, is reduced to an average VLT of 8%.

The south façade in the S Lab presents a stronger case for being shaded for the entire day as it is almost
always subjected to direct sunlight. The design accounted for this by making a large percentage of the
glazing translucent as compared to the NE Lab, which is perhaps why a smaller percentage of the shades
are pulled down in this lab. With 44% of the clear glazing shaded, the average VLT is reduced to 29%.
The translucent glazing, which was 13% shaded, is reduced to an average VLT of 11%.

Table 11. Summary of laboratory shade occlusion
Façade Glazing type
Percent of
total façade
VLT designed VLT in use
NE Lab
east façade
clear 74% 50% 17%
translucent 26% 12% 3%
north façade
clear 69% 50% 23%
translucent 31% 12% 8%
S Lab south façade
clear 50% 50% 29%
translucent 50% 12% 11%

6.1.2 Illuminance

Part (a) of the second research question regarding lighting physics asks how the achieved daylight
illuminance compares to the target daylight illuminance intended by the designers. The designers’ intent
for daylighting illuminance was to earn the LEED v2009 Daylighting Credit. This means that the design
was looking to achieve a minimum of 110 lux in at least 75% of the space at 9 a.m. and 3 p.m. on
September 21. Due to the time constraints of the study, this exact measurement was not recorded. In the
NE Lab, the most similar measurements recorded were at 10 a.m. and 2 p.m. on November 13. At 10 a.m.
80% of the space exceeded illuminance of 100 lux, and at 2 p.m. 60% of the space exceeded 110 lux.
Predictably, the lab easily exceeds the daylighting criteria in the morning but falls short in the evening
when the sun has moved to the opposite side of the building.

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In the S Lab, the measurements most similar to LEED v2009 requirements were recorded on November
10 at 9:30 a.m. and 1:30 p.m. At 9:30 a.m. 83% of the space exceeded 110 lux and at 1:30 p.m. 58% of
the space exceeded 110 lux. Measurements were also recorded in the S Lab on November 20 at 9:45 a.m.
and 1:45 p.m. The percent of floor area above 110 lux was 75% at 9:45 a.m. and 50% at 1:45 p.m. In both
cases, the lab meets the LEED v2009 daylighting requirements in the morning but not in the afternoon.

As discussed previously, the new LEED v4 has tougher requirements to meet in order to achieve the
daylighting credit. Based on LEED v4 requirements, the building should achieve a minimum of 300 lux
in at least 75% of the spaces to earn one credit and 90% of the spaces to earn two credits. Although these
requirements were not the intent of the designers, it is valuable to evaluate whether the building holds up
to current standards, especially considering that it opened only 5 years ago. In the NE Lab, on November
13, 50% of the floor area exceeded 300 lux at 10 a.m. and 15% of the floor area exceeded 300 lux at 2
p.m. Neither of these measurements meets the daylighting requirements of LEED v4. In the S Lab, on
November 10, 75% of the floor area exceeded 300 lux at 9:30 a.m. and 42% of the floor area exceeded
300 lux at 1:30 p.m. On November 20, 42% of the floor area exceeded 300 lux at 9:45 a.m. and 42% of
the floor area exceeded 300 lux at 1:45 p.m. Only the 9:30 a.m. measurements on November 10 in the S
Lab meet the daylighting requirements.

Table 12. Summary of laboratory illuminance results.
Lab Date Time % above 110 lux % above 300 lux
NE Lab Nov 13
10:00 AM 80 50
2:00 PM 60 15
S Lab
Nov 10
9:30 AM 83 75
1:30 PM 58 42
Nov 20
9:45 AM 75 42
1:45 PM 50 42

6.1.3 Glare

Part (b) of the second research question regarding physical light transmission asks whether there is a high
potential for glare discomfort. In comparing the design outcomes to the intent, glare metrics were not
considered in the design process or statement of design intent. Rather, the intent of the designer was much
more qualitative in that the goal was simply to ensure that glare would not be a consistent problem for the
occupants or disrupt their work. Of all of the glare measurements recorded in the NE Lab, the highest
Daylight Glare Probability (DGP) was 0.251, a measurement which was recorded while the shades were
positioned as used (mostly down). In order to test the difference, measurements were also taken with the
shades pulled up, but the highest of those measurements was still only 0.223. All of these values fall within
the range of “imperceptible” glare (DGP < 0.35).

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In the S Lab, very few of the glare measurements exceeded the DGP value for “imperceptible” glare,
except for those recorded at 3 ft from the façade facing south. Inevitably, this lab workstation has DGP
values in the range of 0.248-0.625 depending on the day and time. For most of the S Lab the daylight glare
probability is in the range of “imperceptible.” The only concern is for those working very close to the
façade where the DGP consistently entered the range of “intolerable” glare (DGP > 0.45).

This provided an objective analysis of glare, however glare is highly subjective and sensitivity to glare
varies widely from person to person. Because of this, a subjective assessment is very important to
evaluating the success or failure of glare prevention. A subjective evaluation of glare in the Jorgensen Lab
is analyzed in the occupant survey later in this chapter.

6.1.4 Spectral Power Distribution

Spectral power distribution in relation to circadian response was not a specific consideration of the
designer. Although many designers are aware that daylight and certain wavelengths of light are important
for ideal human circadian functioning, it is not specifically considered in design beyond the need to
provide it. How much daylight is necessary and the best way to deliver it for circadian functioning is less
understood. This analysis corresponds to part (c) of the second research questions which asks in how much
of the space is the lighting spectrum sufficient for melatonin suppression in the occupants. As there is no
set standard or widely recommended value for melatonin suppression, this study define
s “sufficient” as greater than or equal to light capable of achieving a 20% suppression in melatonin after
one hour of exposure.

In the NE Lab, only one location/orientation (15 ft from the south façade facing north) yielded melatonin
suppression less than 20%. The measurement was consistently less than 20% at 10 a.m., 12 p.m., and 2
p.m. This likely occurred due to crowded shelves and large lab equipment blocking daylight from the
north direction. The highest melatonin suppression is, not surprisingly, at 5 ft from the east façade facing
east, with values around 67% all three times of data collection. Recall that the range of possible melatonin
suppression maxes out around 70%, therefore 67% is nearing saturation. Other than these two
observations, there are no trends that stand out dramatically. It appears that at all times of the day, the
lighting spectrum reaching throughout the lab is sufficient for melatonin suppression.

Similarly, in the S Lab, one location (22 ft from the façade facing north) consistently resulted in a
melatonin suppression below 20%. This location, towards the back of the lab, does not receive much
sunlight and the electric overhead lighting is not turned on in this aisle. The instance of 12% melatonin
suppression at 5 ft facing north at 2 p.m. is likely due to similar conditions. Although close to the façade,
the location does not receive much sunlight in the afternoon, the shade closest to the location is always
shut, and the electric overhead lighting is not turned on. Overall, however, most of the lab receives lighting
of a sufficient spectrum for melatonin suppression at all times of the day.

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In both labs, no location was measured in which the melatonin suppression was too low in all cardinal
directions. There were a few locations/orientations where the value was less than 20%, however, simply
by turning to either side or moving around in the lab, an occupant would be exposed to sufficient lighting
spectrum. Even though the shades are limiting daylight penetration, there is still enough daylight entering
the space for circadian stimulus.

6.2 Office & O.M.G. Survey Results Discussion

6.2.1 Glare

Again, part (b) of the second research question regarding physical light transmission asks whether there
is a high potential for glare discomfort. This question was also addressed in the evaluation of glare in the
laboratories. The design intent did not include a specific quantitative goal for glare, but rather simply
aimed to ensure that glare would not disrupt the work of occupants.

Of all of the glare measurements evaluated at occupant desks, there was only one instance in which the
DGP exceeded the “imperceptible” glare threshold of 0.35. Strangely, this instance occurred at Desk 2
located on the north façade of the second floor. This number is interesting because the north façade does
not receive any direct sunlight. The desk is located directly against the north façade and none of the shades
were being used. As seen in the HDR images of Desk 2 in Figure 58, the view towards the façade does
appear excessively bright with the possibility to cause glare likely due to large window area contributing
daylight to the space. These images were taken on a clear, blue sky day.

Figure 58. HDR images of Desk 2 used to calculate DGP.

All of the glare measurements were taken in November, when the sun is low in the sky and has a higher
potential for glare, and also during the time of day in which the space being measured would be receiving

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direct sunlight (morning on the east façade, mid-day on the south façade, and afternoon on the west
façade). Therefore, the measurements were recorded in a worst-case-scenario situation.

Overall, the office spaces performed quite will with only one measurement registering as “perceptive”
glare and the rest in the range of “imperceptive” glare. As mentioned previously though, glare is incredibly
subjective. For that reason, occupant experiences of glare were also evaluated and are discussed later in
the chapter.

6.2.2 Spectrometry

As mentioned previously, spectral power in relation to circadian response was not specified as a design
intent for the Jorgensen Lab. The spectrometry analysis corresponds to part (c) of the second research
question which asks in how much of the building is the lighting spectrum sufficient for melatonin
suppression for the occupants. As there is no set standard or widely recommended value for melatonin
suppression, this study defines “sufficient” as greater than or equal to spectral power capable of achieving
a 20% suppression in melatonin after one hour of exposure.

A number of desk locations were found in which the lighting spectral power was insufficient for melatonin
suppression. These locations were concentrated in two locations: a basement/ground floor office on the
south façade and a first floor office on the north façade. For each of these desk/office spaces, the spectral
power was insufficient (< 20% melatonin suppression) when facing the desk, but sufficient (> 20%
melatonin suppression) when facing towards the façade, indicating that orientation within the spaces is
important.

For the ground/basement floor offices on the south side of the building, spectral power was evaluated with
the shades pulled down as used and again with the shades rolled up. For both desks (6 and 10) that were
evaluated, melatonin suppression was less than 20% when facing towards the desk regardless of whether
the shades were up or down. However, when facing directly towards the façade, the melatonin suppression
jumped from 28.9% to 57.8% at Desk 6 (Figure 59) and from 28.9% to 50.9% at Desk 10. This suggests
that shades do not have a significant impact on spectral power and melatonin suppression unless the
occupant is facing directly towards the façade. The orientation of the occupant has a greater impact on
melatonin suppression than whether or not the shades were in use. It is important to note that were it not
for the “view-preserving” shades, the spectral power and melatonin suppression would almost certainly
not be sufficient as all of the daylight would be blocked. The ability of “view-preserving” shades to
actually preserve the view may be contested, however the 5% openness factor of the shades allows enough
daylight through for circadian stimulus.

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Figure 59. HDR images of Desk 6 with shades up and down. Percentages in the lower left corner of each image are the
melatonin suppression values.

Desks 4 and 13, located in a first floor office on the north side of the building, both showed insufficient
melatonin suppression when facing towards the desk (Desk 4 = 4.4%, Desk 13 = 7.8%). This office has
the smallest window area of any of the perimeter offices and is also blocked from daylight by an
emergency staircase directly outside the window. This is likely the cause of the insufficient spectral power
and melatonin suppression. This is only when facing the desks. When facing the façade, Desk 4 receives
melatonin suppression of 20.5% and Desk 13 receives melatonin suppression of 40.4%.

Figure 60. HDR images of Desk 13. Percentages in lower left corner of each image are the melatonin suppression
values.

There was also one recorded case in which there was insufficient melatonin suppression facing the façade,
but a sufficient value when facing the desk (a counterintuitive result). At Desk 3, located in a first floor
office on the east side of the building, a value of 19.2% was recorded facing the façade and 35.3% when
facing the desk. This office is shaded from the outside by vegetation and had the shades closed on the
inside, so very little daylight was able to penetrate the space. This explains why the spectral power is
insufficient when facing the façade. Interestingly, however, the spectral power was sufficient when facing
the desk. Upon inspection of the HDR images taken at the time of data collection, a task light was switched

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on directly above the occupant’s computer, creating a very bright workspace, and the computer monitor
is switched on. These conditions are unique to this office as the occupant keeps daylight out of the space.
It is possible that the artificial task lighting and/or the computer monitor is/are responsible for providing
sufficient spectral power for melatonin suppression. If this is true, it means that the human circadian
system can effectively function from non-daylight sources in spaces where it might not be possible to
provide daylight (e.g. the light sensitive laboratories in the basement of the Jorgensen Lab).

Figure 61. HDR images of Desk 3. Percentages in lower left corner of each image are the melatonin suppression
values.

Overall, 73% of the spectral power measurements recorded provided sufficient melatonin suppression
with 23% providing > 60% melatonin suppression, approaching saturation. The building is highly glazed,
so this result is not unexpected.

6.2.3 O.M.G. Survey Results

The third research question asks how satisfied the occupants are with the daylight workspaces. The
Occupant Mobile Gateway survey was one way in which this was assessed. The design intent was to
provide ample daylight and views for all of the building’s occupants. Success for this metric is defined as
an 80% satisfaction rate among occupants.

Of the 214 total responses by 15 occupants over two weeks, 50% of the responses were “neutral” to the
question “rate your satisfaction with light from windows.” Another 42% of responses were “low but I am
not bothered,” leaving only 8% for the other three response options. This means that overall the occupants
are satisfied with the daylight, and although sometimes they perceive the daylight to be low they are not
bothered by it. This perception of low daylight is possibly a result of the shades being pulled down in
much of the building.

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The average illuminance for responses (2) “low but I am not bothered” and (3) “neutral” was around 300-
400 lux. This provides some validity to the 300 lux threshold used in calculating sDA. The average
illuminance for response (1) “too low it bothers me” is around 200 lux. The other response options were
not selected enough to be evaluated. The trend in the boxplot shows that satisfaction generally increases
from “too low” to “neutral” as the illuminance increases, an expected result.

Overall, the 80% satisfaction rate for daylight was easily met with 92% of occupants reporting satisfaction.

6.3 Overall Occupant Survey

The overall occupant survey largely provides the analysis for the third research question which asks how
satisfied occupants are with daylight and views in their workspaces.

The first question asked about satisfaction with daylight at occupant desk spaces. Some occupants have
an office to themselves (mostly administrators), and others (mostly graduate student researchers) work in
larger, open-plan rooms with many desks. On a scale from -3 (too little daylight) to 3 (too much daylight)
with 0 being neutral, a majority of the occupants surveyed (8 of 19) responded “0 – neutral.” Another 6
responded “-1 – mostly satisfied” leaning toward too little daylight. This response pattern is very similar
to the results of the O.M.G. survey as discussed in the previous section and is possibly caused by the
shades being pulled down in much of the building. In general, occupants are satisfied with the amount of
daylight at their desk/office workspaces potentially perceiving too little daylight, but not such that it is
bothersome. With a satisfaction rate for daylight in the office/desk spaces of 79%, the result is just below
the pre-defined success rate of 80%.

The second question was the same as the first except that it asked about lab workspaces for those occupants
who also work in one of the building’s laboratories. Of the 16 responses, 6 were “0 – neutral,” 5 were “-
1 – mostly satisfied,” 4 were “-2 – dissatisfied,” and 1 was “-3 – very dissatisfied,” all on the scale of too
little daylight. No one responded on the other side of the spectrum, too much daylight. More occupants
are “satisfied” or “mostly satisfied” with daylight in their laboratory than are dissatisfied, but a third (5 of
16) of the responses also reported dissatisfaction. The survey also asked occupants to report which labs
they work in most frequently, and upon closer inspection of the survey results 3 of the 5 occupants
dissatisfied with daylight in their labs work in the basement laboratories which were intentionally not
daylit due to the light-sensitive nature of the experiments being conducted. The overall success rate for
daylight in the labs is 69%, well below the 80% threshold. However, if the responses are removed of the
occupants in labs which were not allowed to be daylit, then the satisfaction rate increases to 85% (11 of
13 occupants satisfied). Satisfaction is considered to be responses -1, 0, and 1.

The third question asked about occupant satisfaction with views to the outdoors at their desk/office spaces
on a scale from 1 (very dissatisfied) to 7 (very satisfied) with 4 being neutral. Out of a total 19 responses,

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12 were in the satisfied range, 1 was neutral, and 6 were in the dissatisfied range. This is a satisfaction
rate of only 63%. Satisfaction is considered to be responses 5-7. The survey also asked where in the
building their desk is located, but there was no correlation between location and dissatisfaction with views.
The dissatisfaction with views is likely a product of the shade being pulled down in much of the building.

The fourth question more directly tackled the problem of shade usage in the laboratories. The question
asked about occupant satisfaction with their visual connection to the outdoors when the roller shades are
pulled down in the lab. Responses were on a scale from 1 (very dissatisfied) to 7 (very satisfied) with 4
being neutral. Of the total 16 responses, 5 were neutral, 7 were in the dissatisfied range, and 4 were in the
satisfied range. With a satisfaction rate of only 25%, it appears that occupants are not satisfied with views
to the outdoors in the labs when the shades are down. As evidenced by the lack of shade usage though,
this dissatisfaction with views is not motivation to reposition the shades.

The fifth question asked about occupant satisfaction with glare in all of their workspaces (labs and desks)
on a scale of 1 (very dissatisfied) to 7 (very satisfied) with 4 being neutral. Of 19 total responses, 12 were
in the satisfied range, 3 were neutral, and 4 were in the dissatisfied range. Considering satisfaction as
responses 4-7 (neutral to satisfied), the satisfaction rate for glare is 79%, just below the success threshold
of 80%. It should be expected that glare is not a significant problem in the building due to the heavy use
of shades, however there were still a number of people reporting dissatisfaction with glare. The reason for
this result is unclear based on the data gathered.

The sixth question asked about occupant shade usage. The response options were daily/whenever
necessary, a few times per week, a few times per month, a few times per year, or never. Of the 19 total
responses, 14 (74%) responded that they never adjust the shades, 3 (16%) responded that they adjust the
shades a few times per year, and 2 (11%) responded that they adjust the shades a few times per month.
This result indicates that occupants are not actively using the shades to modify their workspaces. Based
on observations of shade positions, it appears that the shades are pulled down when necessary to block
glare, but then they are never readjusted when glare is not present, and the shades remain down
permanently. This pattern of shade usage is not accounted for predictions of daylight autonomy in building
design. In the sDA method it assumed that occupants will pull shades down when there is glare but also
that they will put them back up when glare is no longer present.

The final survey question asked about occupant adjustment of electric lighting. The response options were
daily/whenever necessary, a few times per week, a few times per month, a few times per year, or never.
Of 19 total responses, 9 responded “never,” 4 responded “a few times per week,” 3 responded
“daily/whenever necessary,” 2 responded “a few times per year,” and 1 responded “a few times per
month.” Similar to shade adjustment, a large portion of the occupants report never adjusting the lighting
in their workspaces. Because occupants are not actively adjusting their workspaces, the building is not
reaching its full daylighting potential.

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6.4 Chapter Summary

This chapter discussed the study results in terms of the major research questions. The following is a
summary of the major discussion points for each of the research questions.

1) In regards to the façade, does the achieved visible light transmittance of the façade and components
in use match what was intended by the designer?

The visual transmittance of the façades in the labs is greatly reduced by the interior shades. Assuming that
the design intent is for no shades to be used as often as possible. Through observation it was concluded
that the shades are rarely, if ever, adjusted and most are pulled down at least part way to cover the façade,
therefore the building is not meeting its full daylighting potential. Design intent in terms of façade VT is
not being achieved.

1) In regards to physical lighting properties:

a. Are the horizontal daylight illuminance levels intended by the designer being achieved?

The design intent for daylight illuminance was to meet the daylight requirements for LEED v2009 which
requires 75% of the floor area to exceed 110 lux at 9 a.m. and 3 p.m. on September 21. Due to the time
constraints of the study, these exact measurements were not taken, however data was recorded in mid-
November in the morning and afternoon. Each of the labs exceeded 75% in the morning but not the
afternoon on a clear day with shades kept in the position used by the occupants. Based on these results, it
is possible but not likely that the design intent has been achieved. Perhaps the design intent is achieved if
the shades are not pulled down.

b. Is there a high potential for glare discomfort?

Objectively, measurements of daylight glare probability were quite low throughout the building, with only
a few instances measured of DGP > 0.3. The occupant survey results reinforce these results, with 79% of
those surveyed reported no dissatisfaction with glare, only barely missing the 80% threshold.

c. Is the spectral power distribution from daylight sufficient for human health and well-being,
specifically in regards to melatonin suppression?

Very few instances of insufficient spectral power for melatonin suppression were recorded in the labs and
offices in the building. Even areas with the shades down received sufficient spectral power for melatonin
suppression. Some locations had insufficient suppression when facing one direction, but in every case
changing orientation provided sufficient melatonin suppression.

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1) In regards to human comfort, what percentage of occupants are satisfied with daylight and views
in their workspaces?

A number of questions asked occupants about their satisfaction with daylight and views in their
workspaces. 79% reported satisfaction with daylight in their desk/office spaces. 69% reported satisfaction
with daylight in the labs, and if you discount those that work in labs not allowed to have daylight due to
light-sensitive experiments, the satisfaction rate is 85%. 63% of occupants are satisfied with views to the
outdoors from their desk/office spaces, and 25% are satisfied with views to the outdoors in the labs when
the shades are down.

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7 CONCLUSIONS

This chapter presents the conclusions drawn from the results in regards to the daylighting performance of
the Jorgensen Lab and presents lessons learned which can be used by designers to inform future
daylighting design decisions. Performance was evaluated by comparing the daylighting design intents to
the daylighting outcomes and answering the following research questions:

1) In regards to the façade, does the achieved visible light transmittance of the façade and components
in use match what was intended by the designer?
2) In regards to physical lighting properties:
a. Are the horizontal daylight illuminance levels intended by the designer being achieved?
b. Is there a high potential for glare discomfort?
c. Is the spectral power distribution from daylight sufficient for human health and well-being,
specifically in regards to melatonin suppression?
3) In regards to human comfort, what percentage of occupants are satisfied with daylight and views
in their workspaces?

The results and discussion chapters were organized in two sections: laboratory results and office/desk
results. This chapter is structured differently. The structure of the conclusions follows the format of the
research questions in order to properly draw conclusions for each question all at once.

7.1 Façade Visible Light Transmittance

The research question in regards to the façade asks how the VLT of the façade in use compares to the
VLT as intended by the designer. The intent of the designer was to increase views and daylight in the
Jorgensen Lab, meaning the intent is for the façade to un-occluded for as much of each day as possible.
The building was equipped with “view-preserving” interior roller shades, and it is generally assumed in
daylighting design that occupants will utilize that shades when necessary to block glare. In order to
calculate spatial daylight autonomy (sDA), the simulation is required to assume that shades are pulled
down when illuminance exceeds 1,000 lux and that they are up at all other times.

This pattern of shade usage was not observed however. It was found that occupants tended to pull the
shades down when necessary to block glare but that they did not roll them back up when glare was no
longer present. Instead, the shades remained down indefinitely. This result was shown in two ways: direct
observation/documentation of shade usage (or lack thereof) and a survey of building occupants which
asked how often they adjust the shades. Observation was the first indication that the shades in the
laboratories and occupant desk/office spaces were not being utilized optimally. Occlusion by shades was
found to dramatically reduce the intended VLT of the façade. Survey responses farther reinforced this
finding with 74% of respondents reporting that they never adjust the shades in their workspaces.

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It can be concluded from these results that the achieved VLT of the façade in use does not match that
which was intended by the designers. The façade is underperforming due to poor glare control mechanisms
which rely on optimal, and perhaps unrealistic, occupant participation for daylighting success. A building
such as this one would highly benefit from automated shading strategies, however these are often not
considered due to apparently higher costs. If occupants were actively using the shades then automated
shading would indeed be an increased construction cost with no life-cycle cost benefit. However, since
occupants do not actively use the shades, automated shading could increase lighting energy efficiency use
and therefore would reduce life-costs of the building.

7.2 Lighting Physics

There are three research questions which relate to physical lighting properties in the building. They pertain
to horizontal daylight illuminance, glare, and spectrometry measurements of light spectrum in regards to
human circadian function.

7.2.1 Illuminance

The research question in regards to illuminance asks if the horizontal illuminance measurements intended
by the designer are being achieved. In order to earn the LEED v2009 daylighting credit, the design team
aimed to provide a minimum of 110 lux to at least 75% of the floor area, and had to prove via measurement
that this condition was met at 9 a.m. and 3 p.m. on September 21. Due to the time constraints of the study,
these exact measurements were not taken to verify, however similar measurements were taken in the
second floor laboratories on numerous dates in November.

It was found from these measurements, that the two laboratories meet the LEED v2009 requirement in the
morning but not in the afternoon. The measurements were taken with the shades positioned as used by the
occupants and not as intended by the designers, in order to capture the most accurate representation of the
building’s daylight availability. Separate measurements in the NE Lab show that rolling all of the shades
up can significantly improve daylight illuminance in the lab, however not necessarily to the level needed
to meet LEED v2009 requirements. The design intent has not been achieved.

In addition, daylighting metrics have been greatly expanded upon since the building was constructed. In
order to meet the daylighting requirement for LEED v4 (the current version of LEED), the designers
would have to show via measurement that at least 75% (and preferably 90%) of the applicable floor area
received at least 300 lux from daylight during two times of the year. One morning measurement in the S
Lab just barely met this criteria. It can safely be concluded that (as used with the shades sub-optimally
positioned) the building does not meet the daylighting requirements of the current LEED (and IES)
standards.

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Although it is possible that the building could meet LEED v2009 daylighting requirements as intended by
the designers, it most certainly does not meet present-day daylighting standards. The daylighting potential
of the building is not being achieved and could be improved through more optimal interior shade usage.

7.2.2 Glare

The research question in regards to glare asks if there is a high potential for glare discomfort. Although
no metric was explicitly stated by the designer, it can safely be assumed that the intent was to minimize
glare and provide adequate glare control mechanisms. Only 9 measurements throughout the building
recorded a DGP value exceeding 0.35, above which is considered “perceptible” glare, and 7 of those
measurements were recorded in one location. Even fewer measurements (6) exceeded the threshold for
“disturbing” glare (DGP = 0.4-0.45) and “intolerable” glare (DGP > 0.45), and all were recorded in the
same location. These findings indicate a low potential for glare discomfort in the building.

The survey results reinforce this conclusion, with 79% of occupants reporting no dissatisfaction with glare
in their workspaces. The goal set for success by the author was 80% satisfaction as presented in the
methodology. Although the occupant satisfaction is just barely below the “successful” threshold, it can be
concluded that the designers’ intent to minimize glare was achieved due to the high occupant satisfaction
coupled with the objective results of DGP measurement. The interior shades are performing well in regards
to shade mitigation.

7.2.3 Spectrometry

The research question in regards to spectrometry asks whether the spectral power distribution throughout
the building is sufficient for melatonin suppression by the human circadian system. Glare and illuminance
are well-studied properties in buildings, but light spectrum for circadian response is just beginning to be
studied. Although the basic concept that daylight is necessary for proper circadian functioning is generally
understood by designers, specific metrics are not defined in the design goals beyond the need to provide
daylight. Therefore, it is more difficult to compare design intent to outcomes.

The outcomes, however, are promising for this building. Despite the interior shades being pulled down in
much of the building, there were very few locations in which measured light spectrum was insufficient
for circadian stimulus as measured by a mathematical model predicting the level of melatonin suppression
that would occur after 1 hour of exposure to the measured SPD. In the few locations in which melatonin
suppression was calculated to be less than 20% (defined for this study as the minimal acceptable value),
a simple change in orientation provided a sufficient SPD for melatonin suppression. For instance, if an
occupant received insufficient stimulus while facing toward their desk, turning to face the façade would
provide the necessary stimulus for adequate melatonin suppression. It was found that orientation within a
space had a greater effect on melatonin suppression than position of the interior shades.

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It can be concluded from these results that the spaces of the building designed for daylighting are
performing sufficiently for human circadian function in regards to melatonin suppression.

7.3 Human Comfort

The research question in regards to human comfort asks what percentage of occupants are satisfied with
daylight and views in their workspaces. The design intent was assumed to be 80% occupant satisfaction.

The O.M.G. repeated-measures survey found that the 15 participants in the survey were satisfied with the
daylight in their desk/office spaces 92% of the time, a successful rate of occupant satisfaction. Reinforcing
these findings are the results from the one-time overall survey of occupants in which 79% of respondents
reported satisfaction with the daylight in their desk/office spaces, just barely on the cusp of successful
occupant satisfaction. In the laboratories, only 63% of respondents reported satisfaction with daylight in
the labs, but a few of these responses noted that they work in basement laboratories without windows.
These labs are required to be windowless due to the light-sensitive nature of the experiments and therefore
there is inherently no daylighting potential. Excluding these responses, the satisfaction with daylight in
the labs becomes 85%. With these combined results, it can be concluded that occupant satisfaction with
daylight has been achieved in both the desk/office spaces and daylit laboratories.

Both methods of survey found that although most occupants are satisfied with the daylight, many reported
lower daylight levels than preferred, just not low enough to cause discomfort. It can be concluded from
this that the shade usage is impacting the daylight levels in the building to a degree which is perceptible
by the occupants.

Satisfaction with views was more problematic. When asked about satisfaction with views at their
desk/office workspace, only 63% of respondents reported satisfaction. The question asking about
satisfaction with views in the laboratories specifically asked about satisfaction when the shades were
down, as they often, if not always, were. Only 25% of respondents reported satisfaction with views in the
laboratories when the shades are down. This is despite the use of “view-preserving” shades, which
although preserving some of the view, apparently do not preserve enough of the view to truly satisfy
occupants. It can be concluded from these results that the occupant satisfaction with views has not been
achieved. With shades being positioned down most of the time in most of the building, it is not unexpected
that occupants are unsatisfied with their views. This dissatisfaction, however, does not seem motivation
enough or a high enough of a priority for the occupants to roll up the shades.

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7.4 Summary of Conclusions and Lessons Learned

The conclusions presented in this chapter are summarized in Table 13.

Table 13. Summary of conclusions.
Research Question Design Intent/Goal Reality Conclusion
Façade VLT No occlusion High occlusion Unsuccessful
Physical
Light
Properties
Illuminance ≥ 100 lux, 75% of floor area Only achieved in A.M. Unsuccessful
Glare < 0.35 DGP Most spaces < 0.35 Successful
Spectrometry ≥ 20% melatonin suppression Most spaces > 20% Successful*
Human
Comfort
Daylight ≥ 80% occupant satisfaction 79% (desks), 85% (lab) satisfaction Successful
Views ≥ 80% occupant satisfaction 25% (desks), 63% (lab) satisfaction Unsuccessful
*some stimulus is being provided by electric lighting

The effectiveness of daylighting appears heavily dependent upon an adaptive building. In the case of the
Jorgensen Lab, the ability of the building to adapt to the daylight conditions is dependent upon the
occupants to adjust interior shades and artificial lighting. Both of these things do not appear to be
happening however, meaning that the building is not meeting its full daylighting potential. Although the
lights in the lobby were observed to dim according to daylight levels, this was not observed in the
laboratories or graduate student desk-spaces. The lighting in the laboratories was observed to be turned
on at all times. The lights in the desk-spaces were sometimes turned on or off depending on the occupants’
preferences, even when there was ample daylight availability.

This study and its results provide a few lessons for designers prioritizing daylighting in buildings.

The first lesson is in regards to occupant shade usage. It is prescribed by present daylighting metrics to
assume that occupants are actively using the shading devices in their workspaces to modulate their
environment. Proper shade usage is important to providing sufficient daylighting in the building as it was
designed, but can it be expected of busy occupants to consistently adjust their indoor environment in such
a way? Harsh glare is motivation to pull the shades down, but there is little motivation to roll them back
up when it is far easier and less interrupting of the occupant’s productivity to simply turn on a task light
or to leave the overhead lighting on. It is easy to place the responsibility on a building’s occupants because
it doesn’t seem to be asking much of them. But with evidence that occupants are not using shading
mechanisms as assumed, should designers continue to expect active shade use by occupants or should
they instead design in such a way that depends on nothing but the building itself for proper functioning?
Systems such as automated shades and daylighting dimming lights (which were implemented in at least
some parts of the building) would be extremely beneficial to the Jorgensen Lab. These systems are more
expensive but may actually be worth the cost in the long run.

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The second lesson is more applicable to those who write daylighting metric requirements for rating
systems such as LEED and building codes, but it is also important for designers to know. Despite neither
laboratory meeting the 300 lux daylighting requirement specified by LEED v4 and recommended by IES
(Illuminating Engineering Society 2013), the occupants were generally satisfied with the level of daylight
in their workspaces. These brings up a question of the applicability of these metrics in different types of
buildings and for different occupants.

The final lesson comes back to the fundamental idea of the Jorgensen Lab’s design, which was a
renovation of 1970s building. The original building utilized large concrete shades which prevented direct
sunlight from entering the building, aiding thermal performance and minimizing glare, but also lessening
daylight availability. One of the major goals of the design was to open up the building to allow more
daylight and to improve views both out of and into the building. Although these goals were well-
intentioned, it is important to reflect back on the success of their implementation. The design traded
concrete overhangs for a highly-glazed façade with no external shading. Technically speaking, the original
design is more appropriate for the warm, sunny Southern California climate than the new design, despite
the current aesthetic preference for highly-glazed façades. One of the goals was to improve views to the
outdoors, which were existent but potentially lacking in the original building; however, occupants reported
dissatisfaction with views due to consistent obstruction by interior shades. The outcome is two different
buildings with different limitations, but whether the new design is better than the old is dependent on what
metric is being used to evaluate it. The current Jorgensen Lab is well-daylit with skylights and continuous
façade, but it appears that it could have benefited from exterior shading to shield occupants from too much
direct sunlight from the highly-glazed façade.

7.5 Study Limitations

A number of limitations existed which restricted the scope of the study. The major limitation was time.
As the sun’s path through the sky changes throughout the year, it is necessary to study the daylight
throughout an entire year to get a complete understanding of the daylighting in a building. However, this
study was limited to just a few months (October-November). Studying the winter daylight conditions
provides a sort of “worst-case-scenario” in terms of daylight illuminance and glare as daylight is limited
and the low angle of the sun creates a higher likelihood of glare.

7.6 Future Work

Future work could study the Jorgensen Lab throughout an entire year to gain a more complete
understanding of the daylighting within the building. This study was limited to data collection in October
and November, therefore a full year study could provide a more complete understanding of the daylighting
in the building.

94

Other future work could expand on each of the study’s findings. This study covered a range of measures
related to daylight and each produced interesting results. Illuminance, glare, and spectrometry could each
be studied more thoroughly as a project of its own. For example, a spectrometry focused study could help
better understand the influence of both sunlight and artificial lighting on the human circadian system as
experienced in existing buildings.

95

BIBLIOGRAPHY
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January 13, 2016. http://photobiology.info/Roberts-CR.html.
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Aries, MBC, MPJ Aarts, and J van Hoof. 2013. "Daylight and health: A review of the evidence and
consequences for the built environment." Lighting Research & Technology 6-27.
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Accessed August 23, 2015. http://www.burohappold.com/projects/project/california-institute-of-
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REV2.pdf.
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York: Illuminating Engineering Society of North America.
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Accessed March 2, 2016. http://www3.epa.gov/statelocalclimate/resources/action-guide.html.
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visual satisfaction in a LEED Gold laboratory building." Building and Environment 54-64.
Illuminating Engineering Society. 2013. Approved Method: IES Spatial Daylight Autonomy (sDA) and
Annual Sunlight Exposure (ASE). Illuminating Engineering Society.
Jackson, Laura E. 2003. "The relationship of urban design to human health and condition." Landscape
and Urban Planning 191-200.
Jakubiec, J. Alstan, and Christoph F. Reinhart. 2012. The 'adaptive zone' - A concept for assessing
discomfort glare throughout daylit spaces. Accessed March 3, 2016.
http://jakubiec.net/papers/Jakubiec,Reinhart_2012_TheAdaptiveZone.pdf.
JFAK Architects. 2015. Jorgensen Laboratory Renovation, Caltech: Resnick Sustinability Institute and
Joint Center for Artificial Photosynthesis. Accessed August 23, 2015. http://jfak.net/projects/40.

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Kessner, Claudia, interview by Kelly Burkhart. 2015. Associate Principal, JFAK Architects (October 21).
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Lim, Yaik-Wah, Mohd Zin Kandar, Mohd Hamdan Ahmad, Dilshan Remaz Ossen, and Aminatuzuhariah
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97

APPENDIX

Jorgensen Daylighting Study Follow-Up Survey:

1) Overall, how satisfied are you with the daylight at your desk workspace?
o Very dissatisfied (too little daylight)
o Dissatisfied (too little daylight)
o Mostly satisfied (prefer more daylight)
o Very satisfied with daylight
o Mostly satisfied (too much daylight)
o Dissatisfied (too much daylight)
o Very dissatisfied (too much daylight)

2) Overall, how satisfied are you with the daylight in the lab you work most frequently?
o Very dissatisfied (too little daylight)
o Dissatisfied (too little daylight)
o Mostly satisfied (prefer more daylight)
o Very satisfied with daylight
o Mostly satisfied (too much daylight)
o Dissatisfied (too much daylight)
o Very dissatisfied (too much daylight)

3) Overall, how satisfied are you with views to the outdoors at your workspace(s)?
(Very dissatisfied) 1 2 3 4 5 6 7 (Very satisfied)

4) Overall, how satisfied are you with your visual connection to the outdoors when the roller shades are
down (i.e. lowered) in the lab you work most frequently?
(Very dissatisfied) 1 2 3 4 5 6 7 (Very satisfied)

5) How satisfied are you with glare in your workspace(s)?
(Very dissatisfied – lots of glare) 1 2 3 4 5 6 7 (Very satisfied – no glare)

6) How often do you adjust the shades in your workspace(s)?
o Daily/whenever necessary
o A few times per week
o A few times per month
o A few times per year
o Never

98

7) If/when you adjust the shades, why do you do it?
o To block glare
o To let in more daylight
o To block warmth from direct sunlight
o To allow warmth from direct sunlight
o To improve your view to the outdoors
o Other _________________________

8) How often do you adjust the electric lighting in your workspace(s)?
o Daily/whenever necessary
o A few times per week
o A few times per month
o A few times per year
o Never

9) Overall, how satisfied are you with the Indoor Environmental Quality (daylight, thermal comfort,
acoustics, etc.) of your workspace(s) in the Jorgensen Lab?
(Very dissatisfied) 1 2 3 4 5 6 7 (Very satisfied)

10) Where in the building is your desk located?

11) If you work in a lab, which lab(s) do you work in?

Abstract (if available)

Abstract Daylighting is a common goal for sustainability-focused projects looking to achieve energy efficiency and occupant comfort and well-being. However, it is less common to evaluate the outcomes of these designs once the building is constructed and occupied

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Asset Metadata

Creator Burkhart, Kelly L. (author)

Core Title Daylighting study of a LEED platinum laboratory building: a post-occupancy evaluation comparing performance in use to design intent

School School of Architecture

Degree Master of Building Science

Degree Program Building Science

Publication Date 04/19/2016

Defense Date 03/21/2016

Publisher University of Southern California (original), University of Southern California. Libraries (digital)

Tag daylighting design,laboratory building,LEED,OAI-PMH Harvest,post-occupancy evaluation

Format application/pdf (imt)

Language English

Contributor Electronically uploaded by the author (provenance)

Advisor Konis, Kyle (committee chair), Choi, Joon-Ho (committee member), Kensek, Karen (committee member)

Creator Email kburkhart8@gmail.com,klburkha@usc.edu

Permanent Link (DOI) https://doi.org/10.25549/usctheses-c40-232931

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