A Post-occupancy Evaluation of Patient’s Perception of ...€¦ · factors beyond good medical practices and safe environment that contribute to patient healing. The term „Healing

INTERNATIONAL JOURNAL OF ENVIRONMENTAL SCIENCES Volume 3, No 3, 2012

© Copyright by the authors - Licensee IPA- Under Creative Commons license 3.0

Research article ISSN 0976 – 4402

Received on October 2012 Published on November 2012 1010

A Post-occupancy Evaluation of Patient’s Perception of Visual Comfort in

Hospital Wards

B.Pritam

1, B.Mukta

2

1. Consultant, Enviornmental Architect, Associate- Chandrashekhar architects, Mumbai

2. Assistant Professor, Department of Physiology, Topiwala National Medical College,

Mumbai

[email protected]

doi: 10.6088/ijes.2012030133009

ABSTRACT

Patient‟s perceptions are gaining popularity to evaluate the quality of healthcare facilities

delivered. A study was conducted to understand the visual comfort condition of hospital ward

patients with reference to the physical aspects of natural, artificial and ambient light. We

undertook an observational study in which 136 consecutive inpatients of both the genders

were evaluated. POE (Post occupancy evaluation) questionnaire method for visual comfort in

3 multi-specialty hospitals was used for assessment. Post occupancy evaluation allows direct

comparison of the physical parameters with the inputs of the occupant‟s perception. The

gathered data was analyzed using SPSS statistical package to determine the co-relation in

patient‟s visual comfort and light levels. The qualitative findings noted a positive

contribution of patient satisfaction and daylight (72%) as well as ambient daylight levels

(77%). Thus, there is preference for natural day lighting as against artificial lighting and

natural lighting reduces lighting energy demand. Also, there is a positive preference to certain

illumination quality and levels in patients for visual comfort. This study hence provides data

for visual comfort which is the main and yet understudied determinant of lighting

requirements in a ward setup and also suggests economical recommendations to modify

architectural design and maximize use of natural light in wards.

Keywords: Light; Visual comfort; Post- occupancy evaluation; Academic hospitals; India.

1. Introduction

Hospitals today have evolved as advanced centers for healthcare- diagnostics and research,

recovery and preventive health facilities. Hospitals have a large ecological foot print. The

wards in hospitals form the largest component of any hospital setup. There are a number of

factors beyond good medical practices and safe environment that contribute to patient healing.

The term „Healing environment‟ (Geimer-Flanders, 2009) implies creating an environment

physically healthy and psychologically appropriate which would indirectly contribute to

patient‟s well-being. Indoor environment of these wards play a critical role in recovery of the

patients, where in light has the most significant role in modeling this indoor environment.

Adequate daylight and outdoor view in interior spaces enables efficient performance of visual

tasks and reduce errors in work environment. It has long been identified that light reaching

brain cells affects the body‟s circadian cycles which are biological events that repeat

themselves at regular intervals (Golombek and Rosenstein 2010). When UV light interacts

with skin, it triggers the formation of vitamin D. It is now proved that vitamin D is required

A Post-occupancy Evaluation of Patient’s Perception of Visual Comfort in Hospital Wards

B.Pritam, B.Mukta

International Journal of Environmental Sciences Volume 3 No.3, 2012 1011

not only for bone growth and remodeling but also for immune function, cell growth,

differentiation and apoptosis (Prentice et al. 2008). The role of low levels of vitamin D in

different types of cancer is being widely investigated (Garland et al. 1989; Krishnan et al.

2003; John et al. 1999; Lappe et al. 2007).

Previous studies have also shown a positive association between abundant daylight levels and

physical and psychological well-being after illness or injury. Aldemir (2001) reported

increased frequency of episodes of organic delirium in intensive care unit without windows.

Sunny rooms have been shown to lower the length of stay of patients. Several studies have

shown co-relation between depressive symptoms of seasonal affective disorder (SAD) and

shorter exposure to daylight (Lewy 1987; Terman et al. 1989; Wirz-Justice 2006). A majority

of studies have examined the effectiveness of natural (Benedetti et al. 2001) and artificial

bright light (Beauchemin and Hays 1996; Rosnethal et al.1984) on reducing depression.

An important subjective determinant of lighting levels is visual comfort. It is defined as

satisfaction of visual system and the absence of glare. However, it also depends on several

factors: interaction between all senses, architectural design, mood, aesthetic preferences to

name a few (Dubois et al. 2007). An adequate lighting condition thus control body‟s

circadian rhythm, affects mood and perception and is critical for patient as well as staff well-

being. The POE (Post Occupancy Evaluation) is a sub-process of BPE (Building Performance

Evaluation) and can be defined as act of evaluating a building with a systematic, research

based approach. The early model started in 1960‟s but was detailed and defined by Preiser

((Preiser and Nasar 2008), along with others (Thomson et al. 2003, Carthey 2006 and Cooper

et al. 1991). The study of post occupancy evaluation of Philip Merrill Environmental Centre

(Heerwagen and Zagreus 2005) was a beginning of understanding into how the human factor

impacts sustainable design practice. The results indicated close to 90% of the occupants were

satisfied with day lighting, the overall amount of light, and access to views. The occupant

survey, developed by the Centre for the Built Environment (CBE) at UC Berkeley (Zagreus

et al. 2004) includes a core section with questions on satisfaction with the workplace

environment, and an additional module with questions on psychosocial experience and

organizational satisfaction. The scores clearly indicate the positive response to most criteria‟s,

except the acoustical quality neutrally rated.

This study thereby acknowledged the importance of an evidence-based approach to

architectural design. The study by use of POE (Post Occupancy Evaluation) method aims at

understanding of the actual values as compared to standards. Post Occupancy Evaluation of

lighting in hospital wards allows direct comparison of the physical parameters with the inputs

of the occupant‟s perception.

2. Materials and Method

2.1 Site Description and data collection

This study examines how light affects patient‟s visual comfort in three multispecialty

hospitals in Belgaum, Karnataka, India. The entire data was collected from January 2011 to

May 2011. The sites are identified in one climatic zone as thermal comfort – humidity and

temperature are constant, the visual comfort as prime criteria. The selection of the patients for

interview were based on the variation of ward typologies and further orientation and location

of bed with reference to the source of light. The questionnaire for visual comfort for light was


B.Pritam, B.Mukta


based on the assumption that the patient is hospitalized with a non-critical illness, is not an

emergency case, and not an ophthalmic patient. The questionnaire‟s aim was to understand

the patient‟s response to natural, artificial and ambient light at various time of the day. The

questionnaire was drafted and reviewed by two academic professors for accuracy and validity.

A pilot study in 25 patients was conducted to pre-test the content. The patient‟s response was

graded as satisfactory or non-satisfactory.

2.2 Devices and Instruments

The data collected for lux levels by digital lux meter at bed height (600 mm) at minimum

number of locations as per Bureau of Energy Efficiency (BEE) criteria in the ward with “as-

is” condition. The photometer was calibrated and all the recordings were made at different

time of day and night. Further the daylight component is measured by putting all artificial

light in “switch off” mode. The amount of artificial light during the day, along with the type

of fixture and wattage shall be recorded. The artificial lighting during night shall be recorded,

along with the type of fixture and wattage. The artificial light component is assumed as the

differential between the natural light and the total ambient light. The lighting power density

(LPD) was measured as watts per meter square.

2.3 “Ambient lux level” (Average Illuminance) (BEE Code Lighting, 2006)

Determine the minimum no of readings required as per the Table-1 for RI (Room Index).

Room index, RI = L X W

Hm X (L + W)

Where L = Length

W = Width

Hm= Height of the luminaries above the plane of measurement

Table 1: Minimum number of points for illuminance measurements

Figure 1: BEE Diagram for lux level measurement points

Room index Minimum number of measurement points

For + 5% accuracy For + 10% accuracy

RI < 1 8 4

1< RI < 2 18 9

2< RI < 3 32 16

RI > 3 50 25


B.Pritam, B.Mukta


Average illuminance, Eav = E1+E2+E3+ .......+En X correction factor

N

E1, E2, E3, - - - - En are the Lux Levels at Points “X” in the room.

Correction Factor as per manufacturer or standard Calibrated instrument Refer BEE Code.

Total available lumens on the measurement plane = Average illuminance X (L X W)

3. Findings for visual comfort

Graph 1: Patients preferring natural light viz a viz artificial light

The Y- axis is the no of patients,

X axis 0- no say=12%, 1- artificial light= 15%, 2- natural light = 72.5%

Graph 2: Patients experiencing Glare

The Y- axis is the no of patients,

X axis 0- NA = 5%, 1- No = 60%, 2- Yes = 35%


B.Pritam, B.Mukta


Graph 3: Patients age and satisfaction (Artificial lighting ambient)

The X- axis the age, Y – axis 1- dissatisfied, 2- satisfied

Graph 4: Lighting Power Density and Lux levels

w/sq.m

lux

The Y- axis- LPD, X – axis- L=lux levels


B.Pritam, B.Mukta


Table 2: Ambient Lux levels measured at 0800hrs, patient satisfaction

LUX

Patients Total

NOT

SATISFACTORY SATISFACTORY

< 50

Count 2 4 6

% within

ALL8H 33.30% 66.70% 100.00%

51-150

Count 19 38 57

% within

ALL8H 33.30% 66.70% 100.00%

151-300

Count 4 38 42

% within

ALL8H 9.50% 90.50% 100.00%

301-500

Count 2 25 27

% within

ALL8H 7.40% 92.60% 100.00%

> 500

Count 3 1 4

% within

ALL8H 75.00% 25.00% 100.00%

Total

Count 30 106 136

% within

ALL8H 22.10% 77.90% 100.00%

Pearson Chi-Square value= 18.388 P= 0.001 (significant)


Lux

Patients Total

NOT


> 50

Count 3 3 6

% within

ALL12H 50.00% 50.00% 100.00%

51-150

Count 13 14 27

% within

ALL12H 48.10% 51.90% 100.00%

151-300

Count 3 77 80

% within

ALL12H 3.80% 96.30% 100.00%

301-500

Count 3 20 23

% within

ALL12H 13.00% 87.00% 100.00%

Total

Count 22 114 136

% within

ALL12H 16.20% 83.80% 100.00%

Pearson Chi-Square value= 34.693(a) P= 0.00 (highly significant)


B.Pritam, B.Mukta



Lux

Patients Total

NOT


51-150

Count 10 69 79

% within

ALL16H 12.70% 87.30% 100.00%

151-300

Count 8 16 24

% within

ALL16H 33.30% 66.70% 100.00%

301-500

Count 8 8 16

% within

ALL16H 50.00% 50.00% 100.00%

> 500

Count 7 9 16

% within

ALL16H 43.80% 56.30% 100.00%

Total

Count 33 102 135

% within

ALL16H 24.40% 75.60% 100.00%

Pearson Chi-Square value= 15.855(a) P= 0.001 (significant)


Lux

Patients Total

NOT


>50

Count 16 65 81

% within

ALL20H 19.80% 80.20% 100.00%

51-150

Count 2 46 48

% within

ALL20H 4.20% 95.80% 100.00%

151-300

Count 5 0 5

% within

ALL20H 100.00% 0.00% 100.00%

Total

Count 23 111 134

% within

ALL20H 17.20% 82.80% 100.00%

Pearson Chi-Square value= 30.215(a) P= 0.00 (highly significant)

There is a significant variation in illumination levels within the same ward. There is a

variation in the day light distribution across the ward largely due to size of ward, orientation,

window type, shading type and different elevation of the wards. Out of the 136 patients one


B.Pritam, B.Mukta


respondent was discharged prior to 1600 hrs and another prior to 2000 hrs and hence were

unable to complete the questionnaire.

3.1 Patient satisfaction and daylight/ artificial light

High percentages (72%) of patients prefer daylight (Graph 1). Dissatisfaction of daylight is

mainly due to glare (35% patients experienced glare) (Graph 2). Undesirable glare was found

from artificial lighting in pediatric ward due to fixture mounting at low level and fixture

design.

3.2 Patient satisfaction and ambient light

High number of patients (77%) are satisfied with the ambient daylight levels, expect for some

cases especially during 0800 hrs and 1600hr (Tables 2-5). Though there is an indication of

satisfactory ambient lighting, the in-charge feedback was that there should be better

illumination levels at day and night. Good number of patients (80%) is satisfied with the

ambient artificial lighting, though cases of inadequacy are indicated due to location of fixture,

maintenance, and canopies. Higher percentage of patient satisfaction was found at ambient

day illumination range of 150 to 300 lux as compared to the recommended range of 50 to 150

lux. For night ambient illumination significant number of patient‟s preference was about 50

lux (range 30 to 100 lux) as compared to the recommended range of 30 to 50 lux at bedside

(NBC, 2005).The average patient being aged 40 years and age group ranging from 22 to 75

years, (pediatric ward not considered) there seem to be no clear indication as age related

demand for lighting (Graph 3).

3.3 Lighting Power Density and lux levels

It is observed that the LPD is not largely affected by natural light as the need for power

during natural lighting hours is almost nil. Introduction of proper natural light helped reduce

lighting power requirement during day. The LPD in all the case studies range from minimum

1.46w/sq.m. to maximum 5.62 w/sq.m. for illumination range of 16 lux to 247 lux. The

average at an output of ambient 54 lux at 2.67 w/sq.m. is observed (Graph 4). This is far

below the recommended LPD of 7.5w/sq.m in lux range of 50 to 150 lux for ambient light

(ECBC, 2009).

4. Discussion:

The study explores visual comfort in hospitalized patients. Previous studies have explored the

effect of physical environment in ICU patients and staff (Chaudhary 2009, Shepley et al.

2012, Tsai et al. 2007). However there is a paucity of data with reference to light comfort

levels in hospitalized patients. The study indicated that there is a positive preference to

certain illumination quality and levels in patients for visual comfort. Though there is also a

notable variation to in the indications provided by this sample size, which could imply that

enhanced sample size and parameters could be considered in future for such study. This study

also reinstates the fact that day light is more preferred as compared to artificial light,

indicating its importance in the circadian cycle. This is in accordance with a previous study

by Roche et al. 2000 which illustrated that occupants preferred zones located near windows

for most activities. Also is the established fact that proper consideration of day light in any

indoor environment can stimulate positive response from the occupants; which could be

inferred as that the artificial light must preferably simulate a natural light spectrum cycle.


B.Pritam, B.Mukta


The above also highlights the importance of proper colour rendition and proper distributions

of light, by implementing design parameters that help attain uniformity in illumination,

brightness and prevent glare. The present study has some significant revelations; indicating

the preference for higher range of illuminations as compared to the recommended. The

concept of proper implementation of optimal ambient light and further providing task light is

upheld.

5. Conclusion

The study indicates through inference the validity of the hypothesis; “there is a positive

preference to certain light quality and illumination levels in patients for visual comfort.” It is

also important for patients to experience the changing character of daylight. Further as India

lacks a significant user response based studies in this field, there is a lot of scope and need to

generate larger database to draw affirmative conditions of patients response and guidelines

for lighting in wards with the Indian context.

Recommendations (Architectural Design)

Day Lighting

Achieve adequate and uniform distribution of daylight through design; orientation,

window size, location & glazing type, light shelves, room index, dual source, etc.

Achieve deeper penetration of natural light through design of window, ventilators,

skylight, light shelves, courtyards, light wells, light tunnels, etc.

Prevent glare by providing shading, secondary buffers on inside or outside windows

(corridors), operable screens, etc.

Artificial lighting

Achieve uniform illumination, brightness and proper colour rendition; layout and

distribution, fixture selection, controls, etc.

Prevent glare by appropriate lighting layout and distribution, fixture selection, etc.

Achieve appropriate ambient lighting: lighting distribution, provide task lights.

Enhance indoor light and environment with well maintained indoor spaces, indoor

finishes with adequate co-efficient of reflection, well maintained windows and

glazing.

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A Post-occupancy Evaluation of Patient’s Perception of ...€¦ · factors beyond good medical practices and safe environment that contribute to patient healing. The term „Healing