Shakiba Bagheri

Dr Mohamad Fakri Zaky bin Ja'afar

Prof.Madya Ar. Meor Mohammad Fared

16th February 2015

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Why daylight is important in architecture?• May reduces energy in building

(Lee et al, 2013; Alrubaih et al., 2013; Konis, 2013; Dean, 2005; Zain-Ahmed et al., 2002 )

• May improves indoor environment quality(Galasiu & Reinhart, 2008; Zainordin, Abdullah, & Baharum, 2012; Alrubaih et al., 2013; Li & Lam,

2003; Boyce, 2010; Kim & Kim, 2010 )

• Affects occupants’ visual experience , comfort, and health

(Boyce et al., 2006; Edwards & Torcellini, 2002; Van Bommel & Van den Beld, 2004; Webb, 2006)

Why we need daylighting design assessment?

• Ensure to make full use of daylight while response to the

occupant needs

• Ensure getting the benefits of daylighting

Why daylighting design is important for library?• Importance of good daylight at commercial building

(Galasiu & Reinhart, 2008; C. F. Reinhart, 2006; Fadzil et al 2004)

• Effect of light on reading (Malman, 2004; Othman & Mazli, 2012)

• Effect of daylight on length and quality of stay in library (Kilic & Hasirci, 2011)

• Most of existing studies focused on energy benefits of daylighting strategies

rather than its occupants effects and its possible associated discomfort

problems.

(Zain-Ahmed et al, 2002) (Lee et al, 2013), (Nikpour et al, 2013),

(A.H. Mahdavi 2013)

• Most of previous study did not considers the annual performance of daylighting

and the local climate so they have evaluated daylighting only by static metrics.

(Lim, Yaik Wah ,2011) (Dahlan 2005-library /statics metrics)

(Othman et al, 2012- library/survey) (Fadzil et al, 2004-office/sunlight

penetration and statics metrics)

• Most of previous daylighting assessment studies focused on offices and health

care facilities.

(Lim, Y 2012-office) (Dorasol et al, 2012 and Aripin, S. ,2007-hospital)

Gap:

“Far too little attention has been paid in previous daylighting assessment

studies, to the issue of glare problem and occupant visual comfort, in

a daylit library without sun control shading devices with

considering annual performance of daylighting and local climate of

location.

Research question:What are the effects of implemented daylighting systems at UPM library in

providing visually comfortable environment for users?

The sub-questions:

1. How daylighting is designed in UPM library? ( how is the light admission and control

strategies in the library of UPM)

2. What are the effects of daylighting design implemented in the library on lighting

environment?

3. What is the level of visual comfort for users of case study library?

Objectives:

To understand occupants’ preference and perception and satisfaction level with

different locations and various activities regarding existing daylighting condition in

library setting

To evaluate existing lighting condition in different locations of library

To evaluate the annual lighting environment quality of library and effectiveness of its

implemented daylighting systems

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• Daylighting defined as any methods for admission of daylight into a room

(Manning, 2006) and the controlled use of daylight in and around buildings

(Reinhart & Weissman, 2012)

• Complete definition proposed by Reinhart & Wienold (2011) and Reinhart &

Weissman (2012) is :

Daylighting is “an attempt to optimizing the annual

daylight availability within space while making

that energy efficient and sure that occupants are in

high satisfaction.”

Daylighting design

DAYLIGHTING

The Main Objectives Of Daylighting Design:1. Provide appropriate light level

2. Enhance occupants’ comfort health and

performance

3. Reduce building energy use(Reinhart & Selkowitz, 2006; Galasiu & Reinhart, 2008;

Zainordin, et al, 2012; Alrubaih et al., 2013; Zain-Ahmed et al.,

2002; Li & Lam, 2003; Boyce, 2010; Kim & Kim, 2010)

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Requirement For Daylighting Assessment Are

Review:

At this research the implemented daylighting in case study has been evaluated from the

successfulness of two aspects namely:

Provide appropriate light level DAYLIGHT AVAILABILITY

Enhance occupants’ comfort health and performance VISUAL COMFORT

Daylighting assessment

Daylighting assessment

The most basic metric to measure daylight availability is ‘work plane illuminance’

(Nabil & Mardaljevic, 2005; C. F. Reinhart et al

Dynamic (Climate-based) Metrics:

The basis is absolute values of time-varying daylight illuminances within a

building extend over the whole year with use of annual climate datasets.

Useful Daylight Illuminance (UDI)

the time when daylight levels are useful for building occupants means not too dark

not too bright. (Nabil & Mardaljevic, 2006; Mardaljevic et al., 2009)

with this metric: excludes bright area which are potential of glare or overheating problems

DAYLIGHT AVAILABILITY:• The larger the number of hours per year a daylighting system could meet the required

light level and not exceed the more successful is.

• Daylight availability is affected by natural changes in sun and sky condition (due to

latitude and climate) and building characteristics.

(Loftness, 2013; Zain-Ahmed et al., 2002;Ruck & Aschehoug, 2000;

Mardaljevic et al., 2009; Reinhart & Weissman, 2012)

Assessment Methods:

1. Daylight design guides

2. Field measurement

3. Daylight simulation

(Littlefair, P, 2002; Galasiu and Reinhart ,2008;Reinhart and Weissman ,2012)

• An absolute level of illuminance (as a threshold)for any task fulfilment

recommended by design guidelines. (Illuminating Engineering Society of North America

(IESNA)Malaysian Standards(MS1525:2007)

It is based on : the required accuracy of task .

• The measurement of light level on work plane shows how much measures are

below the thresholds (Hua et al., 2011; Loftness, 2013)

• A daylight simulation is a computer-based calculation which is used to

anticipate the daylight availability amount inside the buildingVariability of daylight availability Climate-based Daylight Modelling software Daysim

Measures spatial patterns of daylight over the whole year - in particular location

annual illuminance profile (temporal map)

(Nabil & Mardaljevic, 2006; Reinhart et al,. 2006; Cantin, F., & Dubois, M ,2011,

Alrubaih et al., 2013; Loftness, 2013)

Daylighting assessment

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VISUAL COMFORT:

Visual comfort: is when the light is enough , comfortable, pleasant

(Iwata et al, 1994; (Dorasol et al., 2012; Kilic & Hasirci, 2011)

Occupants’ preference, perception and satisfaction level

Factors affecting visual comfort: 1. Window design (including shading devices)

2. Light level

3. Glare and effectiveness of shading devices

4. Outside view

(Baker, 2000; Dorasol et al., 2012; Ing, 2013; Mardaljevic et al., 2009; Roche et al., 2000;

Cuttle, 2009; Cantin & Dubois, 2011; Konis, 2013; Dean, 2005)

Assessment Methods:

to evaluate the effectiveness of daylit environment form human perspective

Post Occupancy Evaluation (POE) method

User’s attitude and feedbacks on building performance (Hygge & Lofberg, 1997; Dorasol et al., 2012)

Using socio science- based tools: questionnaire survey, site observation

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to find the effects of a specific daylighting deign on occupants’ visual comfort

quantitative design by doing experiment

Overview Of Research Methods:1. Subjective assessment by questionnaire

2. Lighting measurement at work plane surfaces by Lux meter

3. Daylight simulation modelling of the whole reading areas using ECOTECT and

DAYSIM software

Variables to assess existing lighting condition:

• Amount of daylight for the visual task

• Provision of view

• Avoidance of glare

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Case Study

Daylighting

System

Descriptionc

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Subjective Assessment

• Date: the most problematic time of year /3 days survey from 18th

to 20th June 2013 / examination weeks

• Time: daytime operating hours form 8:30 am to 6:30 pm

• Respondents: individual library users- 98 questionnaire distributed ,85

questionnaire were analyzed

• Questionnaire distribution area: Different selected

area has its own

daylighting

characteristics

including:

• Window direction,

• Windows’ shading

device,

• Distance from

window

• Date: the most problematic time of year /one day 2nd of July

2013

• Time: daytime operating hours form 8:30 am to 6:30 pm.

In existing lighting condition

• Measurement points:

middle of selected tables at perimeter reading area/

Same measurement point for each table at height of

85cm/Interval measurement of 30 minutes

• Instrument: Lutron Lux meter

Field Measurements

• Area A: 6 points

• Area B: 4 points

• Area C: 4 points

Selected areas are

based on

• Existence of

shading devices

• window direction

Daylight Simulation Modeling

• Date: a whole year

• Time: daytime operating hours form 8:30 am to 6:30 pm

• Measurement points: Grid of sensors at 85 cm height from the floor

Daylighting condition only

• Tools: Ecotect and Daysim softwares

• Simulation inputs: project location/ climate data file of Malaysia/

Construction materials

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Result of subjective assessment: preferences

Q20: which one is your

preference about sunlight and

outside view in library?

Result: Most of the respondents

avoid direct sunlight in

choosing their seat at library

however they prefer to have

outside view (78.8%).

% %

Q17: how do you usually prefer to

seat in relation to the windows at

this library?

Result: Most of the respondents

prefer to sit perpendicularly to the

windows (45.2%).

%

Q5: which one you prefer more:

• Artificial lighting

• Natural lighting

• combination

Result: Most of the respondents

prefer to have a combination of

daylight and artificial lighting for

their study at library (48.2%).

Result of subjective assessment: Perception & Satisfaction

Q7: Assessment of total environment of library?

Q10: how do you feel about windows?

Q9: how satisfied are you with the following

aspects of this building in general?

• Lighting

• Window size

• Quality of view

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Effect of activity on visual comfort:(Two related samples test)

There is statistically significant differences between type

of activity and• Satisfaction with amount of daylight p = 0.037paper-based activity (M=3.86, SD=0.91)/computer works (M=3.51, SD=1.02)

• Intensity of disturbing glare p = 0.006computer work (M=3.49, SD=1) /paper-based activity (M=2.94, SD=1.17)

• Amount work area brightness p = 0.048computer work (M=3.49, SD=0.73) /paper-based activity (M=3.29, SD=0.72)

• View reflections on visual field p = 0.000computer work (M=1.69, SD=0.46) /paper-based activity (M=1.18, SD=0.39).

:

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:

Effect of location on visual comfort:(two-independent sample)

There is statistically significant differences between location of users and the

following variables of visual comfort:(Note: area A and B : without any shading devices, area C: with external shading device)

• Users at area A rated the intensity of glare higher than users at area B.

(p = 0.024)

• Users at area C rated the their satisfaction higher than users at area A.

(p = 0.020)

• Users at area C were more satisfied with amount of daylight for computer

works than those at area A. (p = 0.021)

• Users at area A rated their visual task area for computer works brighter than

those at area C. (p = 0.036)

Average

illuminance level

for area

(LUX)

Morning average

(8:30 am- 12:00 pm )

Afternoon average

(12:30pm- 18:30 pm )

Eastward

tables

Westward

tables

Eastward

tables

Westward

tables

Area A 2532.37 3131.12 656.97 528.89

Area B 3460.18 3612.43 1011.73 740

Area C257.43 567.06 100.34 133.1

MS1525-2007:

Appropriate light level for

library : 300-500 lux

Light level above 2000 lux=

high risk of glare and

overheating problems(Nabil & Mardaljevic, 2006; Mardaljevic et al.,

2009)

The average of

illuminance values for

14 measurement

locations

Without shading With shading devices

25

16

7

77

139

78

13

1

86

0

20

40

60

80

100

UDI <100 UDI 100-2000 UDI >2000

Axis

Tit

le

Area BCD Area D Area AE

Useful Daylight Index (UDI)

(% of wok year)

UDI <100UDI 100-

2000UDI>2000

Area BCD 16 7 77

Area D 13 9 78

Area AE 13 1 86

Average 14 5.66 80.33

The UDI above 2000 lux, for all three analysed areas is more than three quarter of a year.

Accordingly it confirms that there is too much daylight in all area of study with the high risk

for glare and overheating problems.

BCD

D AE

BCD

D AE

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• In perimeter area without shading device, there is lots of light,

more than design thresholds, and sunlight exposure for nearly

three quarter of a year ( base on simulation results). Which

resulted visual discomfort problem such as glare for occupants

(survey result) and caused not to be occupied most of the time.

• The study proved the effect of sunlight shading device on

occupants’ visual comfort and providing the stable light level.

• The importance of having daylighting design in library and

the importance of sunlight control strategies at daylighting

design was proved based on occupants’ preference assessment.

it can be concluded that using large glazing area in library without considering proper

shading devices is not supportive for visual comfort of occupants and will cause some

visual discomfort problems.