Pre versus post-occupancy evaluation of daylight quality in hospitals

1. Pre-versus post-occupancy evaluation of daylight quality in hospitals
Hussain Alzoubi a,*, Sana’a Al-Rqaibat a
, Rula F. Bataineh b
a
College of Architecture and Design, Jordan University of Science and Technology, Irbid 22110, Jordan
b
Department of English for Applied Studies, Jordan University of Science and Technology, Irbid 22110, Jordan
a r t i c l e i n f o
Article history:
Received 8 March 2010
Received in revised form
9 May 2010
Accepted 27 May 2010
Keywords:
Daylight
Daylight factor
Illuminance
Luminance
Post-occupancy
Simulation
a b s t r a c t
The purpose of this study is to examine the effect of space occupancy on indoor daylight quality in
hospitals. It assesses the effect of various design variables on the indoor daylight quality in King Abdullah
University Hospital (KAUH) in Jordan. By conducting a comparative study on the indoor daylight quality
of pre- and post-occupancy in patient wards, it was found that hospital occupancy is highly correlated
with indoor daylight quality.
Investigative analysis associated with evaluative approach for daylighting situation in the patient
rooms in KAUH was conducted in two phases: Firstly, pre-occupancy; using the lighting analysis software
(RADIANCE) to conduct graphical and numerical simulation, and secondly post-occupancy, focusing on
field measurements to develop a framework for hospital lighting design.
A representative sample of patient rooms from each wing was selected. The data were categorized
based on the orientation and location of the patient rooms to compare the two phases in terms of
daylight quality.
The study found significant effects of hospital occupation and interior design parameters on the indoor
daylight performance in terms of illuminance level and daylight factor.
Ó 2010 Elsevier Ltd. All rights reserved.
1. Introduction
The characteristics of any built environment influence health
and human productivity in spaces [1,2]. Natural light, unpolluted
indoor air, and good ventilation are essential to improve the envi-
ronment in healthcare buildings. In this context, this study focuses
on daylight in hospitals as a major factor for the improvement of
hospital environments.
Compared to electrical light, daylight in buildings is preferred by
most occupants since it offers dynamic interiors and views [3]. It is
used to maximize occupant comfort, and provide more pleasant
and attractive indoor environment with higher performance and
productivity [4]. Daylight can also reduce energy use and its asso-
ciated environmental emissions [3]. Daylight is also important and
useful in terms of visual comfort and energy-efficient building
design [5].
To the best of the researchers’ knowledge, there is a dearth of
research on the influence of design variables and interior design
parameters on indoor daylight quality. Jordan needs deliberate
research to handle healthcare facility problems in patient rooms
such as lighting, availability of windows in these rooms, daylight
level, and other necessary conditions for patients’ satisfaction.
This study attempts to fill the gaps of research in this field. It
focuses on how hospital occupancy affects indoor daylight quality.
It determines whether or not the indoor daylight quality in
hospitals conforms to the pre-occupancy design criteria. It assesses
the effect of hospital design variables, interior design parameters,
and hospital occupancy on indoor daylight qualities compared to
those predicted by designers in the pre-occupancy stages.
The ultimate objective of this study is to examine the relation
between two major stages of the building life; the pre- and post-
occupancy stages. This will set up a framework for hospital design
focusing on daylight factors to provide architects and practitioners
with information on the impact of hospital design and occupancy
on the quality of daylight. It eventually leads to design of healthy,
comfortable, and energy-efficient hospital spaces.
1.1. Daylight in hospitals
Daylighting has a major impact on the physical performance and
visual comfort of human beings in buildings [6]. The current
research focuses on health, productivity, and economic benefits
from daylighting [3,7,8]. Daylighting is important for human
performance because it affects human beings psychologically and
physiologically [9]. Good daylighting has a positive influence on
health, well-being, alertness, and even sleep quality [7].
* Corresponding author. Tel.: þ962 2 720 1000x26683; fax: þ962 2 720 1038.
E-mail address: alzoubih@umich.edu (H. Alzoubi).
Contents lists available at ScienceDirect
Building and Environment
journal homepage: www.elsevier.com/locate/buildenv
0360-1323/$ e see front matter Ó 2010 Elsevier Ltd. All rights reserved.
doi:10.1016/j.buildenv.2010.05.027
Building and Environment 45 (2010) 2652e2665

2. The importance of natural light for healing has been explored in
different studies [10]. Exposure to sunlight has a positive effect on
patient and staff satisfaction. Daylight can also reduce depression
among patients with seasonal affective disorders and bipolar
depression [11].
Exposure to natural light is associated with mood improvement,
reduced mortality among patients with cancer, and reduced length
Table 1
Geographic and weather information for King Abdullah University Hospital (Jordan
Meteorology Department, 2009).
Latitude 32.54
Longitude 35.85
Altitude 618 m (ASL)
Outdoor average temperature March 12.2 C
June 23.7 C
December 10.7 C
Average sunny hours/day March 7.1 h
June 11.9 h
December 5.4 h
Fig. 1. Illustrations for King Abdullah University Hospital.
Table 2
Reflectance values of building materials in architectural spaces.
Site (post-
occupancy)
Suggested values by
the designer
Recommended surface
reflectance (IESNA, 1995)
Wall 71% 45% 40e0.60%
Floor 46% 27% 20e40%
Ceiling 64% 70% 70e80%
Bed 67% e 25e45%
H. Alzoubi et al. / Building and Environment 45 (2010) 2652e2665 2653

3. Fig. 2. A typical plan for wings A and C of Medical Wards (source: Engineering Projects Unit, JUST, 2010).
Fig. 3. A typical plan for wings B and D of Medical Wards (source: Engineering Projects Unit, JUST, 2010).
Table 3
Properties of windows in wings A, B, C D.
Wings A and C Wings B and D
Window area 7.15 m2
3 m2
Glass type Bronze reflectance Bronze reflectance
Glass transmittance 25% 25%
Window/wall ratio 0.26 0.32
Window/floor ratio 0.38 0.16
Interior elevation
H. Alzoubi et al. / Building and Environment 45 (2010) 2652e26652654

4. of hospitalization for patients who experience myocardial infarc-
tion [12]. Good lighting conditions contribute to the improvement
in productivity, decrease in accidents, increase in mental perfor-
mance, improvement of sleep quality, and increase in morale
among nightshift workers [13]. In addition, lighting has significant
impact not only on the human visual system, but also on the human
photo biological systems as well [3].
Rashid and Zimring (2008) have explored the direct psycho-
logical effects of lighting on healthcare settings and discussed how
light modulations help reduce heart rate, activity level, and respi-
ration rates among infants. They have also explained the influence
of sunlight on patients’ mental health and intake of pain drugs in
hospital rooms [13].
Overall, daylighting in hospitals has a positive influence on both
patients’ physiological and psychological health.
1.2. Post-occupancy in hospitals
Light prediction in buildings in pre-occupancy stages is subject
to change after use. Post-occupancy in its broad concept requires
the involvement of systematic evaluation of occupants’ opinions
about many aspects in buildings. In general, it evaluates how well
a space matches the predicted situation in pre-occupancy stages. In
this study, lighting levels are inspected for both pre- and post-
occupancy. Basically, the predicted light values in architectural
spaces before building occupancy are compared to those of after
building occupancy.
1.2.1. Case study
The researchers chose King Abdullah University Hospital
(KAUH) for many reasons; firstly, this hospital is located in a semi
arid zone where the balance between daylight and thermal models
performance in buildings is much needed. Secondly, this hospital is
the biggest educational hospital in Jordan, and all its physical
problems should be solved for the improvement of the student and
patient environment.
KAUH is part of Jordan University of Science and Technology
(JUST) campus located in the northern part of Jordan. It has
a capacity of 683 beds with a possibility of being increased to 800
beds in any emergency situation.
The hospital is located in the northern part of Jordan; clear sky
conditions are common in this part of the country with few over-
cast sky days in winter. More information about the location of this
hospital is given in Table 1.
The hospital is a 15-storey building, in which all hospital beds
are located; another 3-storey block for outpatient clinics, diag-
nostics and other services is attached to the main hospital part.
Patient rooms occupy the fourth to sixth floor and from ninth to
twelfth floors; the seventh and eighth floors are assigned for faculty
offices.
The high-rise part has four wings connected by an intermediary
structural core. Because the daylight conditions are different in
each wing, the study took four wings for lighting measurements,
wings A, B, C, and D. Half of the patient rooms in wings B and D face
east, and the other half face west. In wings A and C, half of the
patient rooms face south, and the other half face north (Fig. 1).
1.2.2. Reflectance factors
The reflectivity of the surface materials of the patient rooms in
the hospital has been investigated. The reflectance of walls, floors,
and beds are different from the surface reflectance values recom-
mended by the Illuminating Engineering Society of North America
(IESNA). Table 2 compares the recommended reflectance values of
the design stage (pre-occupancy) with the actual values in the
hospital (post-occupancy), and the recommended values by IESNA.
1.2.3. Properties of patient rooms
Based on the number of beds, the hospital has three types of
patient rooms; single, double, and four-bed rooms. The rooms in
the hospital are distributed in the wings as follows; wings A and C
have double and four-bed rooms, and wings B and D single rooms.
This study focuses on the environment of single and double rooms
(Figs. 2 and 3).
The patient rooms in KAUH have two types of windows along
the hospital wings depending on their location; wings A and C have
large windows, and wings B and D have small ones (Table 3). All the
walls and ceilings are made of pre-cast concrete, and the
windowpane is made of regular 6-mm glass of with a transmittance
factor of 25%.
1.3. Methodology
This study examines how the occupancy of hospital buildings
affects indoor daylight quality in patient rooms in King Abdullah
University Hospital (KAUH).
Fig. 4. A comparison between on-site measurements and computed results by RADI-
ANCE software in a selected room in wing B.
Table 4
Placements of reference points in patient rooms in wings A, B, C, and D.
Type A (wings A þ C) Type B (wings B þ D)
12
7
H. Alzoubi et al. / Building and Environment 45 (2010) 2652e2665 2655

5. It uses the well-known building simulation software for lighting
analyses (RADIANCE) and on-site measurement for internal illu-
minance level and daylight conditions in patient rooms. The
dependant variables in the study are illuminance level, luminance
level, and Daylight Factor.
The uncertainty of RADIANCE was checked by taking on-site
measurements and comparing them with the results of the soft-
ware for the same situation. The measurements were taken at 6
reference points in a selected room in wing B. The highest differ-
ence between the software and the real situation measurements
was less than 20% (Fig. 4).
In the field measurements, sample patient rooms from each
orientation in each wing of the KAUH were selected. The data were
categorized based on their orientation and location. The internal
illuminance levels in the sample for post-occupancy were
measured at a height of 0.80 m above the floor using a grid of 1.0 m
by 1.0 m. The lighting measurements were taken at 8 points in
patient rooms in wings A and C and 6 points in patient rooms in
wings B and D (Table 4).
The reflectance values of the existing room surfaces were
obtained using both illuminance and luminance meters. The
illuminance meter is a data logging light meter that stores
lighting readings in an internal memory. It has a very sensitive
sensor that could take different positions based on the light
source. The luminance meter measures the light values directly
reflected from surfaces and shows them on an internal screen
(Fig. 5).
The wall reflectance values were computed by finding the
quotient of illuminance over luminance values at a given point in
the room as follows [14]:
R ¼ L=E (1)
where R: reflectance value of surfaces; L : luminance value; E:
illuminance value.
Fig. 5. Lighting meters used in the study for measuring illuminance and luminance levels.
Fig. 6. KAUH with relation to sun path diagram (source: the authors).
H. Alzoubi et al. / Building and Environment 45 (2010) 2652e26652656

6. Table 5
The status of the four studied wings in terms of shadowed parts during the day.
Time North West South West South East North East
8:00 a.m.
9:00 a.m.
10:00 a.m.
11:00 a.m.
12:00 p.m.
1:00 p.m.
2:00 p.m.
3:00 p.m.
4:00 p.m.
H. Alzoubi et al. / Building and Environment 45 (2010) 2652e2665 2657

7. Table 6
A comparison of illuminance levels between pre- and post-occupancy in wings A and B in KAUH hospital.
Wing Illuminance level (pre and post-occupancy) at the reference points.
A, South
B, East
B, West
Table 7
A comparison of illuminance level between pre- and post-occupancy in wings C and D in KAUH hospital.
Wing Illuminance level (pre and post-occupancy)
C, North
D, East
D, West

8. The data of the pre-occupancy phase were obtained using
RADIANCE. The patient room configurations were modeled using
the Computer Aided Design software (CAD).
The on-site measurements for the current situation were
compared to the results obtained from the computer simulation for
the pre-occupancy stage. A comparison of the two phases was
conducted using the analysis of variance by the 2007 Number
Cruncher Statistical System (NCSS) software.
2. Results and analysis
2.1. Analysis of daylight level in patient rooms
As shown in Fig. 6 and Table 5, the west-oriented patient rooms
in wing B have no direct sunlight in the morning until around 12:00
p.m. Wing C partially blocks the sunlight from the lowest floors of
wing B.
The east-oriented patient rooms in wing B receive direct
sunlight in the upper floors. Wing A casts shadows on wing B and
blocks the sunlight in the lowest floors till 10:00 a.m. At 11:00 a.m.,
all the rooms receive direct sunlight but some lower floors are
partially shadowed by wing A.
The south-facing patient rooms in wing A receive direct sunlight
all year, but wing D blocks it and shades the lowest floors after
12:00 p.m. The south-facing patient rooms in wing C receive
sunlight all day, but wing D blocks daylight and shades it in the
morning (Table 5).
The west-facing patient rooms in wing D receive sunlight after
12:00 p.m. and the east facing patient rooms in wing D only in the
morning until 12:00 p.m. (Table 5).
Table 8
RADIANCE images of luminance ratio for wing A at 1:00 p.m. on December 10th, clear sky.
Type of analysis Wing A, South, at 1:00 p.m., December 10th. Clear sky
Post Occupancy Pre Occupancy
Human Sensitivity
Iso Contour
False Color
H. Alzoubi et al. / Building and Environment 45 (2010) 2652e2665 2659

9. The daylight levels in the patient rooms were measured with
light meters. The measurements were taken in a clear sky condition
on the 4th, 11th, and 15th of December from 11:00 a.m. to 4:00 p.m.
Tables 6 and 7 display a comparison between pre- and post-
occupancy results for the internal illuminance levels in patient
rooms in the studied wings for different days and times. The
computed values from RADIANCE represent the simulated illumi-
nance for the pre-occupancy stage, and the on-site values represent
the measured illuminance in the post-occupancy stage.
The results show that the illuminance values in the pre-occu-
pancy stage are less than those of the post-occupancy stage. For
example, at the reference point 5 at 4 p.m. on December 4th, the
illuminance level is 200 lx for post-occupancy and 100 lx for pre-
occupancy. This difference is subject to change based on the loca-
tion of the measuring points. For instance, at reference point 1 at 1
p.m. on December 10th, the difference between the illuminance for
pre-occupancy and post-occupancy is about 4000 lx (Table 6).
The situation in wings A and C is very similar to that of wings
B and D. The difference between the illuminance levels in the
two stages at reference point 1 at 2:10 p.m. on December 11th is
about 5000 lx. This occurs in the western patient rooms in wing
D. However, the difference between the pre- and post-occupancy
Table 9
RADIANCE images of luminance ratios, wings B and E at 2:10 p.m. on December 11th, clear sky.
Type of analysis Wing B, East at 2:10 pm, December 11th. Clear sky conditions
Post occupancy Pre occupancy
Human Sensitivity
Iso Contour
False Color
H. Alzoubi et al. / Building and Environment 45 (2010) 2652e26652660

10. Table 10
Comparison of daylight factor (DF) between pre- and post-occupancy.
Wing name DF, Pre-occupancy DF, Post-occupancy Difference Percentages
A, South 2.77% 3.12% þ11%
B, East 3.58% 4.75% þ24.6%
B, West 1.41% 1.29% À8.5%
C, North 8.22% 6.54% À20%
D, East 3.37% 4.68% 39%
D, West 11.21% 12.55% 12%
Table 11
Statistical analysis for wings A and B (measured values in December).
Wing Orientation No. of samples Significance Means, lx
A South 22 0.048644
2.95
3.03
3.10
3.18
3.25
post pre
Variables
MeanValue
Means of Mean Value
B
East 18 0.007869
40.00
47.50
55.00
62.50
70.00
POST PRE
Means of Mean Value
Variables
MeanValue
West 18 0.029031
2.10
2.15
2.20
2.25
2.30
POST PRE
Means of Mean Value
Variables
MeanValue
H. Alzoubi et al. / Building and Environment 45 (2010) 2652e2665 2661

11. takes place in all wings all the time. It varies from 25 lx to
5000 lx depending on the time and orientation of the rooms
(Tables 6 and 7).
2.2. Luminance analyses
The luminance values in the patient rooms in the pre- and
post-occupancy stages were simulated using RADIANCE software
for three different days, i.e. the 4th, 10th, and 15th, in three
different months, March, June, and December. Iso-contour line
analysis was conducted on the resulting images to demonstrate
the distribution of the luminance values. The false color analyses
were also applied on the resulting images to demonstrate the
distribution of the luminance ratio in the rooms by the differ-
ences in color distribution The results show that the luminance
values in the pre-occupancy stage are different from those of the
post-occupancy stage. For instance, the luminance values in the
pre-occupancy stage on December 11th range from 1719 to
0.534 Nit while the values of the post-occupancy range from
1646 to 0.276 Nit (Tables 8 and 9).
2.3. Analysis of the Daylight Factor (DF)
For the Daylight Factor calculations, average values from six
grids in the patient rooms were considered. The sensors were
placed one meter away from the window at a height of 0.80 m
which is suitable for the visual tasks most often required by
patients.
The Daylight Factors for pre- and post-occupancy in the patient
rooms in the 10th floors are shown in Table 10. These values are
above the recommended minimum DF in hospitals, which is 1 %
[15]. The Exceptional values have occurred in the west-oriented
patient rooms of wing B and wing C where the DF barely meets the
recommended values for hospitals. As shown in Table 10, the
Daylight Factor differences between pre- and post-occupancy range
Table 12
Statistical analysis for wings C and D (measured values in December).
Wing Orientation No. of samples Significance Means, lx
C North 24 0.009953
450.00
525.00
600.00
675.00
750.00
POST PRE
Means of Mean Value
Variables
MeanValue
D
East 18 0.000091
1.70
1.80
1.90
2.00
2.10
POST PRE
Means of Mean Value
Variables
MeanValue
West 18 0.017649
1500.00
2000.00
2500.00
3000.00
3500.00
POST PRE
Means of Mean Value
Variables
MeanValue
H. Alzoubi et al. / Building and Environment 45 (2010) 2652e26652662

12. from À8.5% to 39%. Most of the post-occupancy cases have higher
daylight factors except for wing B (west) and wing C.
2.4. Statistical analysis of the pre- and post-occupancy data
The internal illuminance levels for pre- and post-occupancy
were measured in patient rooms in the 10th floor of the four wings
in KAUH. The on-site measurements of post-occupancy were
compared with the RADIANCE results of pre-occupancy during
three different days (i.e. Dec 4th, Dec 10th, and Dec 15th) for all the
reference points in each room for different orientations (Tables 11
and 12). Additional simulations of pre- and post-occupancy have
been conducted to compare the two situations in three different
months: March, June, and December (Tables 13 and 14). In this
comparison, one-way analysis of variance was used to compare the
pre- and post-occupancy observations with a different means for
each group. Significance levels of 0.05 and 0.01 were used to test
the samples, which ranged from 98 to 104 readings in each
orientation.
The result of ANOVA for comparing pre- and post-occupancy in
each orientation of each wing showed a significant difference.
Wings A, B west, and D west showed a statistical evidence for the
difference between pre- and post-occupancy situations. Wings B
east, C north, and D east also showed a good proof for the difference
between post-occupancy and pre-occupancy by recording signifi-
cance values less than 0.01 (Tables 11e14).
The statistically significant results commonly prove that
hospital occupancy affects the indoor daylight quality. The interior
design parameters, furniture, and interior surface reflectance have
a strong impact on daylight performance in buildings.
In post-occupancy with higher reflectance surfaces, the illumi-
nance levels increased in wing A by an average percentage of 20.1%,
45.2%, and 39.1% in March, June, and December, respectively, in
wing B east by an average percentage of 46.1%, 47.26%, and 41.87%,
and in wing B west by an average of 26.65%, 27.24%, and 27.20%.
The values increased in wing C by 49.50%, 35.33%, and 42.12%,
in wing D East by 49.46%, 53.68% and 48.56%, and in wing D west,
by 48.48% 42.9% and 39.3% in March, June and December,
respectively.
Table 13
Statistical analysis for wings A and B (measured values along March, June and December).
Wing Orientation No. of samples Significance Means, lx
A South 40 0.009862
2.55
2.61
2.68
2.74
2.80
POST PRE
Means of Mean Value
Variables
MeanValue
B
East 40 0.002360
1.85
1.93
2.00
2.08
2.15
POST PRE
Means of Mean Value
Variables
MeanValue
West 40 0.023741
12.00
12.63
13.25
13.88
14.50
POST PRE
Means of Mean Value
Variables
MeanValue
H. Alzoubi et al. / Building and Environment 45 (2010) 2652e2665 2663

13. The increase of illuminance level in post-occupancy is attributed
to the inter-reflections between the furniture and wall surfaces. The
hospital furniture contributes to increasing the illuminance level
because of its high reflectance values.
3. Conclusions
This study has explored the effects of patient room occupation
and interior design parameters on the indoor daylight performance.
These influential factors were examined using on-site measure-
ments and the building simulation software RADIANCE. The results
show significant effects of hospital occupation and interior design
parameters on the indoor daylight performance in terms of illu-
minance level and daylight factor. Therefore, building occupancy
and the related interior furniture layout can significantly increase
the illuminance level in patient rooms and affect daylight
performance.
The interior design parameter, finishing, and furniture in patient
rooms are essential factors affecting the indoor daylight performance.
These results could only be generalized to hospitals because of the
bright colors of most of their furniture.
Light designers should utilize the effect of interior design in
integrating lighting and thermal models in buildings since efficient
lighting designs normally reduce solar heat gain, which eventually
contributes positively to minimizing energy bills.
Further work need be done to explore the effects of indoor
daylight quality on patient health and performance in hospitals in
Jordan and correlate this effect to various indoor design parameters
for different hospital prototypes.
Acknowledgements
The authors would like to thank Jordan University of Science and
Technology for facilitating this study. Special thanks go to the
administration of King Abdullah University Hospital for being very
cooperative during the on-site measurements. The authors would
also like to thank the University of Jordan for providing the authors
with the necessary tools and devices for conducting this research.
Table 14
Statistical analysis for wings C and D (measured values along March, June and December).
Wing Orientation No. of samples Significance Means, lx
C North 40 0.009123
450.00
525.00
600.00
675.00
750.00
POST PRE
Means of Mean Value
Variables
MeanValue
D
East 40 0.000097
1.65
1.73
1.80
1.88
1.95
POST PRE
Means of Mean Value
Variables
MeanValue
West 40 0.018880
1500.00
2000.00
2500.00
3000.00
3500.00
POST PRE
Means of Mean Value
Variables
MeanValue
H. Alzoubi et al. / Building and Environment 45 (2010) 2652e26652664

14. References
[1] Fisk W. Health and productivity gains from better indoor environments and
their relationship with building energy efficiency. Annual Review of Energy
and Environment 2002;5:537e66.
[2] Seppanen OA, Fisk WJ, Mendell MJ. Association of ventilation rates and CO2-
concentrations with health and other responses in commercial and institu-
tional buildings. Indoor Air 1999;9:226e52.
[3] Leslie R. Capturing the daylight dividend in buildings: why and how? Building
and Environment 2003;38(2):381e5.
[4] Ihm P, Nemri A, Krarti M. Estimation of lighting energy savings from
daylighting. Building and Environment 2008;44(3):509e14.
[5] Li DHW, Wong SL. Daylighting and energy implications due to shading effects
from nearby buildings. Applied Energy 2007;84(12):1199e209.
[6] Chaiwiwatworakul P, Chirarattananon S. An investigation of atmospheric
turbidity of Thai sky. Energy and Buildings 2004;36(7):650e9.
[7] Bommel W. Non-visual biological effect of lighting and the practical meaning
for lighting for work. Applied Ergonomics 2006;37(4):461e6.
[8] SteffyG.Architecturallightingdesign.2nded.NewYork:JohnWileySons;2002.
[9] Croome D. Environmental quality and the productive workplace. London:
EFN Spon; 2003.
[10] Schweitzer M, Gilpin L, Frampton S. Healing spaces: elements of environ-
mental design that make an impact on health. The Journal Of Alternative And
Complementary Medicine 2004;10(Suppl. 1):S-71e83.
[11] Nelson, C, West, T, Goodman C. The hospital built environment: what role
might funders of health services research play. AHRQ Publication No. 05-
0106-EF; 2005.
[12] Walch J, Bruce S, Rabin B, Day R, Williams J, Choi K, et al. The effect of sunlight
on postoperative analgesic medication use: a prospective study of patients
undergoing spinal surgery. Psychosomatic Medicine 2005;67:156e63.
[13] Rashid M, Zimring CA. Review of the empirical literature on the relationships
between indoor environment and stress in health care and office settings:
problems and prospects of sharing evidence. Environment and Behavior
2008;40(2):151e90.
[14] Egan David M. Concepts in architectural lighting. New York: McGraw Hill;
1983.
[15] Thomas R. Environmental design e an introduction for architects and engi-
neer. 3rd ed. London: Taylor Francis; 1996.
H. Alzoubi et al. / Building and Environment 45 (2010) 2652e2665 2665