Varunya Yoon jarunyaroj | AA March Sed Dissertation 2017 by Varunya Yoon Jarunyaroj

RETHINKING HDB FLAT APPLICABLE DESIGN OF PUBLIC HOUSING IN SINGAPORE Varunya Jarunyaroj MArch Sustainable Environmental Design Dissertation Project 2015-2017 AA Sustainable Environmental Design Programme Graduate School Architectural Association School of Architecture

MArch Sustainable Environmental Design Dissertation Project 2015-2017

RETHINKING HDB FLAT APPLICABLE DESIGN OF PUBLIC HOUSING IN SINGAPORE

Varunya Jarunyaroj January 2017

AA Sustainable Environmental Design Programme Graduate School Architectural Association School of Architecture

Abstract In the tropical environment, high level of heat and humidity are primary factors that make air conditioning become a popular yet highenergy-consuming solution for interior cooling for the majority of urban households. With the rising trends in global warming, continued increase in air conditioning usage has become serious environmental concerns over the past decades, calling for the need to rethink of a more sustainable solution to low-energy consuming and environmentally-friendly living space. The dissertation proposes a sustainable, energy-efficient, freerunning design solution for hi-rise residential buildings in Singapore. It is based on theoretical studies and supporting empirical experiments. The proposed approach uses the combination of design and materials to minimize impacts from humidity, while leveraging the benefits from relatively mild temperature for cooling. The solution can be achieved through integrating sustainable design strategies to optimize thermal and daylighting performance, with effective moisture control strategies. The ultimate goal is to create a comfortable and healthy-living environment while reducing the amount of energy consumption and waste. The first stage of the research features breathable material research and design experimentation of a humidity-control equipment" called the “Moisture Membrane” and “Passive Salt Dehumidifier”. The second stage features vernacular case studies, contemporary example researches, fieldworks, and parametric simulation studies. The design outcome which is applicable to both private and public spaces further define effective strategies that can be use to establish and foster stronger bonds among people within the community. The design is proposed for the construction of the Housing and Development Board (HDB) flat which is the government-developed public housing occupied by majority of Singaporeans.

Authorship Declaration FoRm

SUSTAINABLE ENVIRONMENTAL DESIGN PROGRAMME ARCHITECTURAL ASSOCIATION GRADUATE SCHOOL

PROGRAMME :

MArch Sustainable Environmental Design

SUBMISSION :

MArch Dissertation

TITLE :

Rethinking HDB Flat : Applicable Design of Public Housing in Singapore

NUMBER OF WORDS:

11,710 (excluding footnotes and references)

STUDENT NAME:

Varunya Jarunyaroj

DECLARATION: "I certify that the contents of this document are entirely my own work and that any quotation or paraphrase from the published or unpublished work of others is duly acknowledged"

SIGNATURE:

DATE:

January 27h, 2017

TABLE OF CONTENTS Abstract Acknowledgement Table of Contents Introduction

1. Context and Theoritical Background 1.1 Geographic Information 1.2 Climate and Comfort Analysis 1.3 Historical Background and Demography 1.4 Economic Background

5 7 8 10 12

2. Humidity Control Study 2.1 Methods 2.2 Breathable Materials and Application 2.3 Moisture membrane 2.4 Salt Passive Dehumidifier

13 15 16 20 22

3. Case Studies 3.1 Vernacular cases 3.2 Contemporary Examples

25 27 37

4. Fieldwork 4.1 Scope and Area of Study 4.2 The HDB Flat Community 4.3 Fieldwork 4.4 Summary

41 43 44 45 55

5. Analytic Work 5.1 Objectives 5.2 Parametric Studies

57 59 60

6. Guideline 6.1 Objectives 6.2 Development Guidelines for New Flats 6.3 Improvement Suggestion for Existing Flats

69 71 71 73

7. Design Applicability 7.1 Site Analysis 7.2 Programming 7.3 Outdoor Design 7.4 Indoor Design

75 77 81 83 101

Conclusion

115

References List of Figures and Tables Appendices

119 121

Acknowledgement First of all, I would like to express my sincere appreciation to Simos Yannas, Jorge RodrĂguez Alvarez, Mariam Kapsali, and all SED teaching staff for their guidance especially to the Co-Director of the SED Programme, my dissertation adviser, Dr Paula Cadima, who has given me constant support both morally and academically. I would also like to extend my gratitude to all my friends and classmates for all the support and good memories we have had, especially to Wan Fong Wu for going through all the ups and downs with me. Thanks to my co-founders at Rice Popper Co., Ltd., Professor Lindsay Bremner, and Assistant Professor Apiradee Kasemsook for their endorsement which led to this wonderful experience. Thanks to all my friends in Singapore for their warm welcome and cooperation which allowed me to complete my field study. Moreover, I would like to thank AA staff for their assistance, most notably to Clement Chung for his kindly understanding and eagerness to help. Finally and most importantly, I would like to declare how grateful I am for the support and encouragement I received from my family who never once failed to believe in me. A special thanks to my significant other, Som, for her endless patience and all her efforts.

RETHINKING HDB FLAT : Applicable Design of Public Housing in Singapore

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INTRODUCTION RESEARCH QUESTIONS HYPOTHESES METHODOLOGIES OUTCOME SUMMARY

RETHINKING HDB FLAT : Applicable Design of Public Housing in Singapore

INTRODUCTION Fig. 1 Multi-row panorama of HDB flats in Bukit Panjang Source: Soo, 2013

Fig. 2 Air-conditioners usage in HDB flats. Source: Project Manhattan, 2014

76% of households in Singapore own air-conditioners1 At glance, the number might not be surprising considering the tropical climate the country is in. However, in comparison, the country’s year-round air temperature is actually milder than those of other countries within the same region. As such, what is the cause of high demand for airconditioners among the Singaporean households? And most importantly, is it possible to create a sustainable solution to curb down the demand in order to reduce the country’s overall electricity consumption? Despite mild temperature, Singapore’s humidity level is considerably high. It creates a negative impact on body’s comfort as heat triggers the body’s mechanism to perspire to cool off the body; however, high level of humidity subsequently prevents the sweat from evaporating away leaving people to feel sweaty. The combination of heat and humidity is deceiving as it makes people feel hotter than it truly is. As a result, air conditioning has been chosen as a popular method to cool down the living space quickly, when in fact dehumidification method is instead required to provide comfort in such mild-weather environment. Over the past centuries, Singaporean residential building typologies have evolved over time from Malaysian Kampong houses, to the colonial style shop-houses, and to modern HDB flats. The evolution highlights the changes in how building structures have gradually influenced indoor cooling method over time. Under vernacular design, traditional homes were constructed to be functional and suitable to the local climate conditions, leveraging on essential construction elements and simple tools. With the absence of advanced technologies, the vernacular design clearly relied on people to alter their behaviours in order to obtain comfort while in different living spaces. Modern home design, in contrast does not

Fig. 3 Three generations of Singapore Housing

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Fig. 4 (Left) Household Electricity Consumption Source: National Environment Agency, 2016 Fig. 5 (Right) Sketch of urban heat island profile in Singapore Source: Wong, 2002

focus heavily on the functionality and climate compatibility. It overlooks the benefits from design simplicity and rely more heavily on the convenience of technology development in air conditioning instead. This dissertation proposes a sustainable, energy-efficient, freerunning design solution for public housing buildings. The proposed approach is to use the combination of design and materials to minimize impacts from humidity. The solution can be achieved through combining sustainable design strategies that optimize thermal and daylighting performance, with effective moisture control strategies. The ultimate goal is to create a comfortable and healthy-living environment while reducing the amount of energy consumption and waste.

Endnotes

1 Department of Statistic, 2016

● The first chapter of this dissertation will provide a brief summary on the context analysis including theoretical background. ● The second chapter will discuss the study of humidity control techniques covering a comprehensive analysis of breathable material properties which will lead to the selection of appropriate materials that could deliver positive effects on indoor moisture content levels. This chapter also further discusses the effectiveness of two elements of the humidity control equipment called the “Moisture Membrane” and “Passive Salt Dehumidifier”. ● The third chapter features case studies of vernacular architecture and contemporary examples. ● Chapter Four provides details on the fieldwork which features a thorough analysis of the existing public housing in Singapore. ● Chapter Five is the analytical work including parametric studies of thermal models and daylighting analysis simulations. ● The research completed up to this point will be concluded and illustrated in Chapter Six as a form of design guidelines for both existing and new developments. ● Chapter Seven describes the design outcome which comprises both comfortable and efficiently-used private and public spaces. Lastly, the chapter also proposes a flexible engagement strategy that should establish and foster stronger bonds among people within the community.

RETHINKING HDB FLAT : Applicable Design of Public Housing in Singapore

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1. CONTEXT AND THEORITECAL BACKGROUND 1.1 GEOGRAPHIC INFORMATION 1.2 CLIMATE AND COMFORT ANALYSIS 1.3 HISTORICAL BACKGROUND AND DEMOGRAPHY 1.4 ECONOMIC BACKGROUND

RETHINKING HDB FLAT : Applicable Design of Public Housing in Singapore

CHAPTER 1. CONTEXT AND AND THEORITECAL BACKGROUND 1.1 GEOGRAPHIC INFORMATION The Republic of Singapore is a single city country located on a group of islands situated in South-East Asia on the south border of Malaysia. The total area of Singapore is 718.3 km2 (in 2014)2 which could be considered the second smallest country in Asia after the Maldives. However, Singapore keeps extending its land size by reclaiming coastal areas, hence the total size is continually changing. To travel from the east end of the city to the west end would take only 40 minutes by car. Despite its size, Singapore is one of the most powerful developed countries in the region. The terrain of Singapore is relatively flat with the lowest and highest altitude of zero metres and only 163 metres above sea level respectively. There is absolutely no alteration of climate conditions across the island. The location of the island is slightly above the equator and therefore in a hot and humid tropical region. With close proximity to the equator, the country experiences equal amount of day and night hours throughout the year.

103°51′E

1°18′N

Equator

Fig. 6 Singapore Location on the World Map

Fig. 7 Satelite map of Singapore (Source: Google Map 2016)

agricultural land: 1% arable land: 0.9% permanent crops: 0.1% permanent pasture: 0% forest: 3.3% other: 95.7%

Fig. 8 Geographic and altitude diagram

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1.1 CLIMATE AND COMFORT ANALYSIS

337.50

22.50

Outdoor Temperature

35°C

Avg

292.50

247.50

112.50

225.00 202.50

3 m/s

100

Diffuse

2 m/s

1 m/s

0 [Wh/m2]

0m/s

250

<=0.00

MAR

FEB

MAR

345.00 67.50

E 112.50 135.00

6 mm 6 mm 5 mm 5 mm 4 mm 4 mm 3 mm 3 mm

292.50

W 247.50

202.50

157.50 S

135.00 157.50

157.50

337.50 345.00

E 5.00 4.00 112.50 3.00 2.00 1.00

135.00

1 m/s 1 m/s 0m/s 0m/s

<=0.00

8.00 7.00 6.00 5.00 4.00 3.00 2.00 1.00

<=0.00

22.50 45.00

45.00

67.50

247.50

112.50 225.00 202.50 S

Max Drybulb Temperature Min Drybulb Temperature

22.50

67.50

202.50

200 200 Speed [m/s] Wind Global 3 m/s 150 Mean 150 Outdoor Temperature [°C] Global 3 m/s Maximum Mean Outdoor TemperatureDiffuse [°C] 100 2 m/s Diffuse 100 Minimum Mean Outdoor Temperature [°C] 2 m/s

N 337.50

292.50

225.00

157.50 S

135.00 157.50

112.50

135.00

Wind Speed [m/s] Wind Speed [m/s] Mean Outdoor Temperature [°C] Mean Outdoor Temperature [°C] Maximum Mean Outdoor Temperature [°C] Maximum Mean Outdoor Temperature [°C] Minimum Mean Outdoor Temperature [°C] Minimum Mean Outdoor Temperature [°C] Comfort Band [°C] Comfort Band [°C] Precipitable Water [mm] Precipitable Water [mm] Global Horizontal Radiation [Wh/m2] Global Horizontal Radiation [Wh/m2] Diffuse Horizontal Radiation [Wh/m2] Diffuse Horizontal Radiation [Wh/m2] Relative Humidity [%] Relative Humidity [%]

31 C 25 C

APR

MAY

JUN JUL AUG CLIMATE SUMMARY

SEP

OCT

NOV

DEC

APR

MAY

JUN

JUL

AUG

SEP

OCT

NOV

DEC

30 20 25 15 20 10 15 5 10 0

225.00

22.50

35 25

112.50

Singapore Airp.

JAN

7.00

Sun Path Sun PathN 45.00

202.50

8.00

Singapore Airp.

35 30

67.50

m/s >=10.00 >=10.009.00 9.00

In Singapore, there are little changes in temperature level and precipitation level across seasons throughout the year. The monthly average mean temperature is around 27°C, while the average minimum and maximum are 25°C and 30°C respectively. The climate analysis chart (Figure 9-10) shows that the overall outdoor air temperature is usually within the comfort band. This information leads to the question of why nearly 80% of households in Singapore own air-conditioners. As discussed earlier in the introduction section, the information given on Figure 9 suggests that the constant average high humidity at 83% is a causeSUMMARY for the high demand for air-conditioners. CLIMATE

Fig. 10 (Below) Comfort Analysis Chart After : Brunelli, 2015 FEB

247.50

Diffuse Horizontal Radiation [Wh/m2]

Fig. 9 (Above) Climate analysis of Singapore in current and predicted situation

JAN

m/s

45.00

Sun Path

50Band [°C] Comfort 50 0 Water [mm] Precipitable 0 2 [Wh/m ] 2 [Wh/m ] Horizontal Radiation [Wh/m2] Global

27 C 83 %

22.50

6.00

225.00

Relative Humidity [%]

Annual Average Data Mean Drybulb Temperature Relative Humidity

22.50

67.50

202.50

JAN FEB JAN MAR FEB APR MAR MAY APR JUN MAY JUL JUN AUG JUL SEP AUG OCT SEP NOV OCT DEC NOV DEC

Global

Wind Speed

150

250

N 337.50

292.50

157.50

Relative Humidity

200

Horizontal Solar Radiation

250

Horizontal Solar Radiation

Relative Humidity

3 mm

Min

135.00

247.50

Min

Wind Speed

60%

2.00

Wind Speed

4 mm

3.00 Avg Avg

Precipitation

5 mm

70%

337.50 345.00

4.00

Precipitation

80%

Precipitation

6 mm

Max Max 5.00

1.00

337.50

90%

292.50

7.00

15°C 345.00 15°C 292.50 90% 90% 80% W 80% 70% 70% 247.50 60% 60% 225.00

15°C

345.00

6.00

20°C 20°C

20°C

>=10.00 9.00 8.00

67.50

25°C 25°C

Min

JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC

m/s 45.00

30°C 30°C W

Max

25°C

Outdoor Temperature

345.00 35°C 35°C

30°C

Prevailing Wind Prevailing Wind N

Climate Analysis: Singapore Prevailing Wind Climate Analysis: Singapore 2050

Climate Analysis: Singapore

AVERAGE WIND SPEED [m/s] AVERAGE DAILY DIFFUSE HORIZONTAL SOLAR RADIATION [ kWh/m²] AVERAGE MONTHLY MEAN TEMPERATURE [°C] AVERAGE WIND MONTHLY MIMIMUM TEMPERATURE [°C] AVERAGE SPEED [m/s] AVERAGE DAILY DIFFUSE HORIZONTAL SOLAR RADIATION [ kWh/m²] AVERAGE MONTHLY MEAN TEMPERATURE [°C] AVERAGE MONTHLY MIMIMUM TEMPERATURE [°C]

AVERAGE DAILY DIRECT HORIZONTAL SOLAR RADIATION [kWh/m²] Comfort band limit [°C] AVERAGE MONTHLY MAXIMUM TEMPERATURE [°C] AVERAGE DAILY DIRECT HORIZONTAL SOLAR RADIATION [kWh/m²] Comfort band limit [°C] AVERAGE MONTHLY MAXIMUM TEMPERATURE [°C]

The research by Jitkhajornwanich, K. (2006) claimed that people tend to adapt and feel that the extra 2-3K above comfort band range is positively acceptable. Furthermore, the upper comfort band could be extended by 2K. Therefore the upper comfort band range used in this project is 1K wider than the ASHRAE 55 standard Also, base on observation, it could be concluded that people in hot and humid always appreciate slightly cold weather hence the lower comfort band will not be focused on on this dissertation

RETHINKING HDB FLAT : Applicable Design of Public Housing in Singapore

Figure 11 illustrates climate analysis using a psychrometric chart further confirms that dehumidification is required in order to achieve a comfortable environment. Relative humidity does not only affect bodyâ&#x20AC;&#x2122;s comfort, but it also does harmful effects on people's health. Figure 12 exhibits a healthy relative humidity range which is an optimal extent that could neutralise the adverse health effects caused by moisture.

Fig. 11 Psychrometric chart for Singapore climate After: Climate Consultant 6.0

Asthma is one of the top 4 burden diseases in Singaporean children age 0-11and Respitatory involve disease is one of the top 10 burden diesease in adult citizens Optimum Healthy Relative Humidity Range 40 - 60 % Singapore Annual average Outdoor Relative Humidity 83% Fig. 12 Healthy indoor relative humidity range Source: Arundel et al. ,1986

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1.3 HISTORICAL BACKGROUND AND DEMOGRAPHY Fig. 13 Boat Quays in 1900 Source: G.R. Lambert and Company, 1900

Fig. 14 Boat Quays 2014 Source: Causse 2014

Initially, a trading port city of Malaysia in the Kingdom of Singapura, Singapore was exceedingly valuable which meant it was occupied by many powerful nations. In the 1970s, Singapore finally gained its independence, and with the leadership of Prime Minister Lee Kuan Yew, Singapore almost immediately leapt out of third world country status and became one of first world affluence. However, this accelerated development did not come without drawbacks. Consequently, the population grew out of control. Chinese immigrants made up a majority share of the community while the rest of the locals are native Malaysian and the rest are Indian. Furthermore, the current demographic situation has changed as the economy grew. Presently 43% of the population are foreign-born and in which 3/4 are still working-permit holders. Moreover, within three generations, Singapore has lost the population age balance, to be more precise, similar to many developed countries, the percentage of the elderly population has grown larger and out of proportion. The situation drove the government to prolong the retirement age further with a campaign to re-employ older citizens back to work.3 Fig. 15 Population Trends 2016 Source: Department of Statistic, 2016

RETHINKING HDB FLAT : Applicable Design of Public Housing in Singapore

2012

Fig. 16 Population age proportion in 2012 and Prediction in 2050 Source: Department of Statistic, 2016

2050

The rising number of people combined with the scarcity of land pushed the government to come up with proper urban planning and management hence the Housing and Development Board (HDB) was established to tackle the housing crisis. The HDB has consistently been responsible for building high-rise public housing apartments to provide affordable housing for people. Consequently, 80% of the Singaporean population today reside in HDB flats. HDB flats do not just provide people with housing but also essential amenities tied to the concept of urban planning which aims to decentralise and adequately provide people with local and regional facilities for a comfortable life in their community. Located within reach of most of the HDB flats are convenient stores, nurseries, playgrounds, green spaces, community areas, and recreational grounds. The well-planned city and social structure solved social problems such as the low employment rate and housing crisis. Controlling the number of privately-owned cars in the city making Singapore on of the cleanest and safest cities in the world. Singapore’s urban planning has become well known as an excellent model for urban planning.

Fig. 17 (Above) Singapore urban concept plant diagram After: Bin, T.S.,no date Fig. 18 (Below) HDB flats and local amenities

WOODLAND REGIONAL

RESIDENTIAL AREA

LOCAL

SCHOOL

TAMPINES REGIONAL

TOH PAYOH CITY CENTERFRINGE

JURONG EAST REGIONAL

LOCAL MALL

HAWKER CENTER

PARK RECREATIONAL

INDUSTRIAL DICTRICT

CITY CENTER

INDUSTRIAL ZONE

TOURIST ATTRACTION

COMMERCIAL CENTER

CITY CENTER BUSINESS DISTRICT

ttttdddfdsf ttttdddfdscxvxcvedwerwrwerwerwerewrr



 mama shop

Meeting Area

ttttdddfdsf

Sport and Recreation

Park

UNIVERSITIES

Pavillion

Coverd Walkway

Nursery

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1.4 ECONOMIC BACKGROUND The deficiency of land in Singapore also affects the nation’s resources. It is confirmed that, at the moment, Singapore has no choice but to rely on imported energy The report (EMA, 2015) pointed out that 85% of Singapore’s electricity demand is met by imported natural gas, the rest of the 15% of the electricity demand is from other sectors. The concern about these unsustainable energy supplies led the government to seek new sources of cleaner energy. The study by NUS (Nian, 2010) suggested that moving toward renewable sources of energy would be a sensible step to make, Singapore could replace natural gas electricity plants with nuclear and coal plants, or import power directly from neighbouring countries. The water situation seems more promising than the energy issue, but Singapore is still en route to achieving its goals of being able to supply 80% of its water demands. The country currently has five NEWater4 factories which cleanse reclaimed water and two desalination plants. These two types of facilities can now provide up to 55% of the overall water demand5. The rest of the water supply is mainly imported from a river in Johor Bahru, Malaysia. However, Singapore’s stand in a water agreement with Malaysia is endangered. The river in Johor Bahru itself has been facing an extended period of dry-spell annually, and when this issue occurs, the river can only provide five million gallons a day while being tied to the agreement to allow Singapore to draw up to 250 million gallons daily. As a result, Singapore, in turn, supplies Johor potable water during this yearly occurrence6. Consequently, the country is striving to move toward more sustainable resources by developing renewable supplies as well as raising people’s awareness to generate better users behaviour. Moreover, the urban farm movement, which is happening nationwide, creates an opportunity for Singaporeans to be more self-sufficient. The government also has started building "living labs" and an "eco-town" to test how efficiently PV panels work and can be maintained in high humidity. While executing the plan to resolve this circumstance, Singapore is reported to still import at least 90% of their food, 80% of their energy, and up to 50% of their water.

Endnotes

2 Wikipedia, no date 3 Ministry of Manpower, 2016 4 NEWater = high-grade reclaimed water produced from treated used water that is further purified using advanced membrane technologies and ultra-violet disinfection, making it ultra-clean and safe to drink 5 Singapore National Water, no date 6 Malaysiakini, 2016 12

RETHINKING HDB FLAT : Applicable Design of Public Housing in Singapore

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2. HUMIDITY CONTROL STUDY 2.1 METHODS 2.2 BREATHABLE MATERIALS AND APPLICATION 2.3 MOISTURE MEMBRANCE 2.4 SALT PASSIVE DEHUMIDIFIER

RETHINKING HDB FLAT : Applicable Design of Public Housing in Singapore

CHAPTER 2. HUMIDITY CONTROL 2.1 METHODS As previously stated, humidity plays a major role affecting peopleâ&#x20AC;&#x2122;s comfort in the hot and humid atmosphere while also reduce buildings' endurance. Hence, indoor humidity controls are important in a climate like Singaporeâ&#x20AC;&#x2122;s. Logically, two major solutions to deal with humidity are moisture control and dehumidification. First, moisture control involves managing medians of moisture preventing the indoor conditions from getting more humid, to be more precise, this solution involves restraining moisture content from sources such as the kitchen, toilet, or outdoor environment. Second, to make the damp indoor environment less humid by getting rid of the humidity caused by internal factors or inescapable moisture content using a dehumidification process. The study on the humidity controls strategy is divided into two parts: 1) Literature review The first part involves literature reviews focusing on the breathability property of selective materials to gain advantages and avoid issues using materiality. 2) Experiment The second part features experiments regarding the understanding of the effectiveness of the humidity control solutions which lead to the design applicability of the moisture control equipment and dehumidifier. Controlled environment (Data logger 1) Data logger 2: Base case

Source of heat

Fig. 19 Experimentation set-up diagram

Data logger 3: X case

Hygrometer Temperature: 28-32 C RH: 75-85%

Source of moisture

Fig. 20 Images of experimentation set-up

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The experiments were conducted using a control chamber with heat and humidity sources to raise the temperature and humidity to a tropical range. After that, two identical boxes with the same opening size were put in, one is a controlled subject box which is empty, and another box is for test subjects. Three data loggers were used to keep records of temperature and relative humidity in the control chamber, the controlled subject box, and the test subject box for comparison. The conclusion of the research will be explained further in the following three sections giving descriptive information on how each strategy worked and their applications. 2.2 BREATHABLE MATERIAL AND APPILCATION Moisture transferred through building envelopes can negatively influence its nature and lower the material’s strength and durability. In some cases, accumulated dampness in building elements could drop resistance characteristics and could potentially cause mild electric shocks from a short circuit. This situation in normal cases would not be fatal; however, it certainly creates an annoyance to everyday lives. Additionally, the stored or transferred moisture could affect indoor moisture levels as the moisture moves through the building envelope. Understanding material breathability properties means defining how moisture content moves through the substances' bodies and this is a crucial key to maximising material durability and maintaining a comfortable indoor condition. The three features which distinguish breathability are: ● Hygroscopicity: the ability to absorb and release moisture content. ● Vapour Permeability: the ability to let the vapour move through. ● Capillarity: the ability to transfer and release water in liquid form.

Fig. 21 Breathable material properties and suitable application ACCEPTABLE LEVEL

VAPOUR PERMEABILITY

HYGROSCOPICITY

Quick Moderate Slow

FLOOR CEILING EXTERIOR WALL INTERIOR WALL

● ● ● ● ● ●

STRUCTURE

●●● ●● ●● ● ● ●

FOUNDATION

● ● ●● ●● ●● ●●●

● ● ●

CAPILLARITY

RETHINKING HDB FLAT : Applicable Design of Public Housing in Singapore

Fig. 22 Materials properties and the application diagram

6v Vapour Water Insulation Low permea Heat

Different building elements need different breathability characteristic. Structures, floors, and ceilings require less permeability and capillarity as possible while hygroscopicity is although unnecessary but desirable. It means that if these building elements get in contact with the water in any form, the transfer of moisture content would be slow or halted, however, in the case that the parts have absorbed water, it is better if they could release the water quickly. Next, it is preferable for typical internal walls to have high hygroscopicity while moderate to low capillarity and permeability are acceptable as their chances of exposure to water are considerably low. To be more specific, the interior wall should be able to dry quickly while the ability to absorb and let water through should be kept at the minimum. Finally, the breathability requirement for external walls is ideally unique. Initially, they should have high hygroscopicity which means they would be able to dry quickly but also have low capillarity so that when it rains, they will not absorb water. High permeability is highly required so the walls can let the vapour buffer through. This property can be an advantage when there are differences between humidity levels on both sides of the walls. However, the ideal aspect of the exterior wallsâ&#x20AC;&#x2122; property is that it should only work one-way. When the humidity level inside is higher, the walls should transfer moisture content from inside to outside, on the other hand, the property ought to shift and stop the transfer when the condition is reversed. OUT

WHEN THE HUMIDITY INSIDE IS HIGHER 17

OUT

WHEN THE HUMIDITY INSIDE IS LOWER

Fig. 23 Exterior wall property diagram

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ROOF

EXTERNAL WALL

Rice hull insulated concrete slab

Rendered unfired clay brick with shutter

U Value

0.5 W/m2K

U Value

FLOOR

0.8

Concrete and Bamboo laminate U Value 0.8 W/m2K

Concrete (Dense) U Value 0.6

Fig. 24 Material Selection

W/m2K

STRUCTURE

INTERNAL WALL

GLAZING

Rendered unfired clay brick

Single clear 6mm

U Value

U Value 3.1

1.3

W/m2K

Accordingly, the main selection of materials regarding their individual breathability requirement are: Dense concrete is commonly selected for building structures, especially in high-rise buildings because of its strength and handy application. Dense concrete is considered not breathable; it would be used as a structural element and foundation where the impact from water and vapour should be minimal. ● Timber Timber usually absorbs and release moisture quickly, but it does not allow the transfer through. In this project, the main sources of timber are renewable rubber ash and bamboo which grow well in Thailand and Malaysia. ● Unfired Clay Brick Stufy The internal and external walls feature unfired clay brick as the main structure combined with lime rendering and appropriate cladding. Unfired clay brick is similar to traditional brick, but its production using radiation from the sun to dry instead of fire or manufactured heat causes them to have a lot less embodied carbon. They dry quickly and importantly let vapour transfer through. Nevertheless, the capillarity level of unfired clay brick alone is high and therefore a suitable render is needed. ● Hygro-skin This composited material allows the possibility to create the ideal property for external walls. Hygro-skin is a climate responsive material which was a part of FARC Centre Oelean done by a team from The ICD from University of Stuttgart in 2013. The way hygro-skin works is simply by using the property of a thin layer of wood which has a natural mechanism to quickly change its shaped in response to the humidity level. This property in a natural setting could be seen in pine cones which could change their outer skin shape according to the dampness in the air as shown in Figure 25. The application of hygro-skin on the external walls as seen in Figure 26 and 27 would create an automatic adaptability to slow down or stop moisture buffering when the humidity outside gets higher.

Fig. 25 Hygro-Skin Source: Menges et al., 2013

RETHINKING HDB FLAT : Applicable Design of Public Housing in Singapore

40% RH

45% RH

50% RH

55% RH

60% RH

65% RH

70% RH

75% RH

Fig. 26 (Above) How Hygro-Skin work Source: Menges et al., 2013

OPEN Fig. 27 (Above) Function and application of HygroSkin cladding

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2.3 MOISTURE MEMBRANE

Fig. 28 Fog catcher in Peru Source: Lavars, 2015 The fog catcher project originated in Peru where there is a lack of water and rain while, on the other hand, fog occurs quite frequently. Mesh structures are installed where the fog occurs to trap water from the air. The water captured from this device, even though it is not palatable, could be stored for other purposes. In tropical regions, natural ventilation could be the cause for high indoor humidity as moisture content would be freely let in along with the cool air. The fog catcher project proves that mesh surfaces can capture moisture from the atmosphere. Applying this methodology to use as a moisture control strategy might work. Like the fog catcher, applying a mesh surface on spaces’ openings could generate a similar effect by trapping the incoming moisture content while still allowing adequate ventilation.

Fig. 29 Moisture Membrane testing result : bamboo screen

Several test subjects were tested, namely, cotton meshes of various mesh size and handed-weaved bamboo mesh. The result in Figure 29 shows that the bamboo mesh works the best by decreasing the humidity by 8% while slowing down the wind speed by half. Average of 001 Temperature Average of 002 Temperature Average of 003 Temperature Average of 001 Humidity Average of 002 Humidity Average of 003 Humidity

100 95 90

Relative Humidity (%)

85 80 75 70

Values

9% RH Diffrence (%)

Wind flow property 2.5 m/s 1.2 m/s Values

Average of 001 Te

Average of 001 Temperature Environment Temperature

(°C) (°C) Average 003 Temperature Test ofSample Temperature (°C) Max of 001 Humidity RH (%) Environment Average 002 Humidity BaseofCase RH (%) Average 003 Humidity Test ofSample RH (%) Average 002 Temperature BaseofCase Temperature

Average of 002 Te

Average of 003 Te

Average of 001 Hu

Average of 002 Hu

Temperature (°C)

45 40 35 30 25 20

DAY 1

DAY 2

DAY 3

DAY 4

DAY 5

2016-09-21

2016-09-22

2016-09-23

2016-09-24

2016-09-25

00:00 02:00 04:00 06:00 08:00 10:00 12:00 14:00 16:00 18:00 20:00 22:00 00:00 02:00 04:00 06:00 08:00 10:00 12:00 14:00 16:00 18:00 20:00 22:00 00:00 02:00 04:00 06:00 08:00 10:00 12:00 14:00 16:00 18:00 20:00 22:00 00:00 02:00 04:00 06:00 08:00 10:00 12:00 14:00 16:00 18:00 20:00 22:00 01:00 03:00 05:00 07:00 09:00 11:00 13:00 15:00 17:00 19:00

Bamboo Screen (Hand made) Material : Bamboo Opening size : 2 mm Manufacture :Thailand

Date

Time

Average of 003 Hu

RETHINKING HDB FLAT : Applicable Design of Public Housing in Singapore

Figure 30 exhibits the application of mesh surface on the opening. The first type of application will be on the top ventilator which will be opened 24 hours to slowly ventilate and cool down the space while the adaptive membrane screen will be applied to the operable windows. Fig. 30 Moisture Membrane application

NORMAL MODE

OCCUPIED HOURS MODE

2.4 SALT PASSIVE DEHUMIDIFIER Fig. 31 Hygroscopic property of salt Salt drawing water out of cucumber with out direct contact Source: Blonder, 2011

Salt is a hygroscopic substance which has a supplementary ability not just to absorb water, but it can draw water out of sources via the surrounding air. Figure 31 demonstrates how salt draws water out from a piece of cucumber without direct contact. People use salt widely for this ability to preserve food or to keep storage dry. Many old rock salt quarries are later converted into storage facilities where a steady level of humidity is required. Testing how well salt works in the dehumidification process, a tray of salt was put into a test subject box. The result indicated that the salt could lower the relative humidity level from three to five percent. The experiment also covers other hygroscopic substances such as rice and crushed charcoal; however, salt proved to work the best.

Average of 001 Temperature Average of 002 Temperature Average of 003 Temperature Max of 001 Humidity Average of 002 Humidity Average of 003 Humidity

MArch SED 2016

100 95 90

Relative Humidity (%)

85 80 75 70

Values

Average of 001 Tem

Average of 002 Tem

Average of 003 Tem

Max of 001 Humidit

Average of 002 Hum

RH Diffrence (%)

3-5 %

Average of 003 Hum

Temperature (째C)

Average of 001 Temperature Environment Temperature

(째C) Average 002 Temperature BaseofCase Temperature (째C) Average 003 Temperature Test ofSample Temperature (째C) Max of 001 Humidity RH (%) Environment Average 002 Humidity BaseofCase RH (%) Average 003 Humidity Test ofSample RH (%)

11:00 11:30 12:00 12:30 13:00 13:30 14:00 14:30 15:00 15:30

Fig. 32 Dehumidifier testing result : Salt

Fig. 33 (Left) Portable passive salt dehumidifier After: The humidifier expert, 2015 Fig. 34 (Right) The proposed passive salt dehumidifier

35 30 25 20

Date

DAY 1

DAY 2

2016-08-10

2016-08-11

00:00 22:00 23:00 23:30 22:30 00:30 01:00 01:30 02:00 02:30 03:00 03:30 04:00 04:30 05:00 05:30 06:00 06:30 07:00 07:30 08:00 08:30 09:00 09:30 10:00 10:30 16:00 16:30 17:00 18:00 18:30 19:00 19:30 20:00 20:30 21:00 21:30 22:00 23:00 23:30 22:30 11:00 11:30 12:00 12:30 13:00 13:30 14:00 14:30 15:00 15:30

Values

Time

A DIY style salt dehumidifier as shown in Figure 33 is broadly adopted and used. A number of users claimed that these devices could reduce the interior relative humidity of up to 15%.7 The proposed device would be inserted into the floor featuring a salt chamber and water chamber divided by the fine mesh in the middle. The lid is an aluminium grate which people can step and walk over. When the salt absorbs the water, it will get saturated and become smaller until it falls through the divider and dissolves into the water. The water chamber connects to a separate sewage pipe, and the stored water can be used for various purposes others than potable water, for example, watering plants, by diluting it at 1:15 ratio with clean water, flushing, and or let back into the main sewage. All the occupants need to manage to maintain this device is to put in more salt.

SALT MESH DIVIDER WATER

Water Water pipe Chamber connect to the storage system

Salt

Endnotes 7 Malowski, 2014

RETHINKING HDB FLAT : Applicable Design of Public Housing in Singapore

Humidity Screen Preventing Vapour to get in with ventilated air

Passive Dehumidifier

Fig. 35 Diagram of moisture control devices

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RETHINKING HDB FLAT : Applicable Design of Public Housing in Singapore

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3. CASE STUDIES 3.1VERNACULAR CASES 3.2 CONTEMPORARY EXAMPLES

RETHINKING HDB FLAT : Applicable Design of Public Housing in Singapore

CHAPTER 3. CASE STUDIES 3.1 VERNACULARE CASES Vernacular architecture is a good example of how humans built their dwellings to be suitable for the climate. Without today’s advanced technology, people in the past learned how to adapt and make use of what they have and to use only what was essential. Undoubtedly, the sustainability of vernacular houses is indeed unquestionable as the slow pace of lives before the industrial revolution were low in carbon emissions, low in energy consumption, and not wasteful. On the contrary, architecture today is far from essential since people’s perceptions have changed while their lives have become more convenient. Capitalist lifestyles are wasteful and greedy as people believe they can get more when they can sacrifice only a little. Learning from vernacular models provides a better understanding of adaptive opportunities and strategies that could be valuable lessons for the new design. Instead of focusing the study on changes in the design of residential buildings in Singapore in three generations (Kampong house, Colonial style shop house, and HDB) this study will expand to pursue more schemes from different countries in the neighbouring region. The criteria for vernacular case selection are to choose cases from cities which share similar climate characteristics with Singapore. Appearances such as materiality, building mass form, and roof size and shape of the standard models need to be to a certain level, unique and provocative. The selection of vernacular examples which were chosen from various cities and countries are: ● Malay Kampong house from Singapore ● Thai-Muslim Blanor house from Songkhla, Thailand ● Toba Batak house from Medan, Indonesia

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Fig. 36 Selected Vernacular Cases

Malay Kampong house

Thai-Muslim Blanor house

Toba Batak house 28

RETHINKING HDB FLAT : Applicable Design of Public Housing in Singapore

3.1.1 Malay Kampong House Fig. 37 Traditional Kampong house Source : Radschool Association Magazine, 2013

A Kampong house is rarely seen in Singapore nowadays as the old settlements were replaced by larger capacity buildings to fulfil the requirement of housing and working space for the rising population. Some of the Kampong houses were found reserved on the Palau Ubin island north-east of the mainland; however, the condition and materials of these Kampong houses were modified for the purpose of easy maintenance. Unlike the modern version of residential buildings, the traditional Malay house manifests a clear expression of the unique culture and way of life. The evolution of the Malay Kampong house is seen through its dependence on nature and respect for ecological balance. They are efficiently designed to make coping easier. Apart from the various strategies applied to help those who live there adapt to the environment, Malay Kampong has developed a flexible prefabricated building system to satisfy individual requirements. Furthermore, it also fulfils the need for the immediate expansion of the houses which is a cultural identity of extended Malay families.

Structure

Wall

Floor

Roof

Window

Timber

Rubber ash with air gap

Rubber ash

Thatch

Composited Timber

Fig. 38 Kampong houses on Palau Ubin Island

Fig. 39 Materiality of Kampong houses

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Fig. 40 Kampong house strategies diagram Source: Yuan, 2002

The structure of a Kampong house is a simple post and lintel using materials that could be obtained locally. The main structure is solid timber. The overall space is raised on stilts with the wall and floor made of lightweight materials varying from solid wood to weaved bamboo panel. A thatched roof provides sound insulation and protection from high solar radiation. A Kampong house habitually features plenty of windows to stimulate sufficient ventilation at body level which would cool the occupantsâ&#x20AC;&#x2122; body directly. Body level ventilation works together with roof-joint ventilation which allows a stacking effect to happen and helps to bring the hot air which rises to the top, out of the house. The openness of the design is also reflected in an open plan layout of the interior space which uses a minimum number of partitions. Spaces are instead divided by differences in floor levels. The large size roofs with extended eaves protect walls and windows from solar radiation. Moreover, the design also minimises the glare problem by blocking the visual field from open skies.

The orientation of the Kampong house follows religious beliefs; hence, they traditionally face east and west8 to face the direction of Mecca. This orientation beneficially lessens the exposure to direct solar radiation. The outside of the house is often densely shaded with trees and vegetation which would lower the temperature around the house since vegetation and trees do not absorb, store, or radiate heat. The use of vegetation around the houses reduces reflective outside surface. Grilles and carved wooden panels are also used to distribute the brightness controlling the daylight at a more useful level.

Fig. 41 Diagram of space usage in Kampong houses Source: Yuan, 2002 30

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3.1.2 Thai-Muslim Blanor House The city of Songkhla is located in the southern part of Thailand. The climate of this region is tropically hot and humid, similar to Singapore; the average temperature is higher while relative humidity is slightly lower. The culture and way of life of Malaysian Muslim and Thai-Muslim households are very similar therefore the way interior spaces were used are almost identical. Thai-Muslim vernacular houses are divided into categories by the shape of the roofs. The scope of this research only focuses on the Blanor house which is the most commonly seen today. Prevailing Wind

Climate Analysis: Songkhla, Thailand

337.50

22.50

345.00

Outdoor Temperature

35°C

m/s 45.00

292.50

30°C

8.00

67.50

7.00 6.00

Max

Avg

25°C

247.50

Min

112.50

5.00 4.00 3.00 2.00 1.00

225.00

135.00 202.50

<=0.00

157.50 S

20°C

Sun Path 337.50

22.50

345.00

Relative Humidity

6 mm

80%

5 mm

70%

4 mm

60% 300

3 mm

250

45.00

292.50

Precipitation

90%

Horizontal Solar Radiation

15°C

67.50

W 247.50

112.50 225.00

135.00 202.50

157.50 S

200

Wind Speed [m/s]

Global

150

Mean Outdoor Temperature [°C]

3 m/s

100

2 m/s 1 m/s

0 [Wh/m2]

0m/s

JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC

Maximum Mean Outdoor Temperature [°C] Wind Speed

Diffuse

Minimum Mean Outdoor Temperature [°C] Comfort Band [°C] Precipitable Water [mm] Global Horizontal Radiation [Wh/m2] Diffuse Horizontal Radiation [Wh/m2] Relative Humidity [%]

Fig. 43 Songkhla location and climate Analysis

Fig. 44 Traditional Blanor house Source : Vernacularachi, 2017 Structure

Wall

Floor

Roof

Window

Rubber ash and Bamboo

Bamboo Stripe/ Timber

Rubber ash and Bamboo

Thatch

Composited Timber

>=10.00 9.00

Fig. 42 Materiality of Blanor house

MArch SED 2016

Plan and Elevation of Blanor

Kitchen Bed room

North Elevation

Entrance Porch

The Blanor house structure developed a prefabricating system which can be taken apart and reassembled. A basic lightweight construction of post and lintel timber raises the house on timber posts standing on stone footings to avoid damage from floods. A thatched gable roof provides good insulation. Bamboo weaved panel or solid timber planks are common wall materials. However, in some unique cases, the weaved bamboo panels were used to cover the floor instead of the typical solid timber with gaps. It could be thought that these floor constructions with gaps behave as another channel of ventilation. Window design in Blanor house is mostly full-height providing full Kitchen East full-height Elevation ventilation and views. The window consists of three parts: the top which has fixed ventilation panels, the operable window in the middle is solid, but in some of the cases, the solid panel is replaced with grills Entrance which allows the window to act as a ventilator when closed. The bottom Porch Bed room part functions similarly to the top, but in some examples, this panel is shut with solid panels behind a decorative railing. The interior layout of the house is open plan with split floor levels for different spaces allowing proper ventilation flow. The significance of the orientation of the Blanor house is unfounded. and Elevation of Bumbung Panjan More likely, the building order and orientation are determined based on location, social relationships, culture, and lifestyle. Some of the older examples still face east and west, facing the traditional direction of Mecca8.

Fig. 45 Blanor house characteristic Plan and Elevation of Malaek Source: Santisan, nodate

Plan

Fig. 46 Thai-Muslim Blanor house strategies diagram

Bed room

Kitchen

Entrance Porch N

Figure 3. shows 4 main types of roof forms

East Elevation

Although the Bumbung Panjang roof form that was influenced from Malaysia W is the oldest identified in Satul, the most common roof form found all over the border of southern Thailand nowadays is Blanor.

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3.1.2 Batak Toba House The climate of Medan is similar but warmer in comparison to Singapore. The average air temperature is higher with a wider range between minimum and maximum while the average relative humidity is slightly lower for 75% of the year. The most striking element about the Batak Toba house is its boat-like shape with a roof that curves like a saddle. Prevailing Wind

Climate Analysis: Medan, Indonesia

337.50

22.50

345.00

Outdoor Temperature

35°C

292.50

30°C

>=10.00 9.00 8.00

67.50

7.00 6.00

Max

Avg

25°C

m/s 45.00

247.50

112.50

5.00 4.00 3.00 2.00 1.00

Min

225.00

135.00 202.50

<=0.00

157.50 S

20°C

Sun Path 337.50

22.50

345.00

Relative Humidity

6 mm

80%

5 mm

70%

4 mm

60% 300

3 mm

250

45.00

292.50

Precipitation

90%

Horizontal Solar Radiation

15°C

67.50

W 247.50

112.50 225.00

135.00 202.50

157.50 S

200

Wind Speed [m/s]

Global

150

2 m/s

Diffuse

1 m/s

0 [Wh/m2]

0m/s

JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC

Maximum Mean Outdoor Temperature [°C] Wind Speed

100

Mean Outdoor Temperature [°C]

3 m/s

Minimum Mean Outdoor Temperature [°C] Comfort Band [°C] Precipitable Water [mm] Global Horizontal Radiation [Wh/m2] Diffuse Horizontal Radiation [Wh/m2] Relative Humidity [%]

Fig. 47 (Left) Medan location and climate Analysis

Fig. 48 Batak Toba house Source : Oxborrow, 2015 Structure

Wall

Floor

Roof

Window

Rubber ash and Bamboo

Timber

Rubber ash and Bamboo

Thatch

Composited Timber

Fig. 49 Materiality of Batak Toba house

MArch SED 2016

Fig. 50 Blanor house characteristic Source: Knecht et all., 1983

The construction of the Batak Toba house uses complex craftsman skill which forms a mixture between a post and lintel system, frame system, and load-bearing wall systems. Even though the Batak Toba house is raised from the ground like Kampong and Blanor houses, the proportion is different. The timber pillars lift the house up only 1.5 metres on flat stone footing allowing the ground space to store animals; the footing prevents dampness from travelling up the structure. A few of these pillars stand stretch up to the roof level to support the roof structure. The walls are lightweight composited constructions of solid timber. These walls support the roof structure which is why they lean out to give the overall structures more stability. Most of the lower constructions and building elements are timber while the roofs are mainly of a bamboo structure. Without any internal structure, the space under the thatched roof provides an ample storage space. The steeply-pitched roof project, triangular eaves, and gable overlap covering all the lower parts, however, the protruded roof on the side of the house are only shortly extended out while the front and rear gables extend further. Unlike other discussed examples, the windows of the Batak Toba house are small and there are only a few to provide the occupants with the feeling of security at night. Even though the occupants usually spend the daytime outside, the small windows which allow inadequate ventilation could cause a problem when cooking, leaving the open living space smoky. Nevertheless, the small windows do give benefit by minimising external heat gain and solar radiation. However, this configuration could cause health problems because of the unventilated air and indoor humidity. The front and rear end of the Batak Toba always orient north and south as to protect the often used space underneath. E

Fig. 51 Thai-Muslim Blanor house strategies diagram

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3.1.4 Summary

ORIENTATION AVOIDING SUN ORIENTATION TO CATCH WIND HIGH PITCH ROOF BODY HEIGHT VENTILATION LARGE ROOF EAVES WEATHERPROOF FOUNDATION ELEVATED FLOOR TO GET STRONGER WIND LIGHT AND QUICK DRY MATERIAL ROOF INSULATION OPEN PLAN FOR BETTER VENTILATION FLOW LOW WINDOW TO FLOOR RATIO TO AVOID SUN WINDOW AS VENTILATION WHEN CLOSE ROOF VENTILATION (24hr ventilation)

● ● ● ● ● ● ● ● ● ● ● ● ●

Figure 52 illustrates the useful strategies extracted from each vernacular case study which include: 1) Using orientation avoiding high solar gain 2) Roof-joint ventilation to ventilate hot air 3) Body height ventilation cooling occupants’ bodies directly and evaporating sweat 4) Large overhang protecting the indoor space from sun penetration and high solar radiation 5) Grill element protects indoor space from diffuse solar radiation 6) Open plan layout and cross ventilation supports better ventilation rate 7) Waterproof foundation 8) Lightweight and quick dry material 9) Roof insulation 10) Low window to floor ratio helps limit external heat gain

N N S S Orientation

c Roof ventilation

B Open plan + Cross ventilation Flood proof foundation

Low window to floor ratio

● ● ● ● ● ● ● ● ● ● ● ● ●

Fig. 52 Vernacular cases analysis summary

Fig. 53 Useful strategies from vernacular cases

Body height ventilation

Large eaves

s Light and quick-dry material

kk Orientation to catch wind

● ● ● ● ● ● ● ● ● ● ● ● ●

Windows as ventilator

w Roof insulation

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Endnotes

8 Facing East-West Orientation is to face the front of the house (short span) toward East and West Directions

RETHINKING HDB FLAT : Applicable Design of Public Housing in Singapore

3.2 COMTEMPORARY EXAMPLES 3.2.1 The Case of Forecourt at Bedok Court Condominium

Fig. 54 Bedok Court Condominium Source: Kiechle, 2008 In a traditional Malaysian Kampong (village), the veranda space is always the liveliest areas. The shaded veranda spaces are visually connected to streets and used for numerous purposes: play spaces for children, meeting guests, having dinner, or even just relaxing. The verandas filter the public and private space but at the same time encourage connection within the neighbourhood. This socio-environmental phenomenon occurs in relation to the existence of semi-open spaces in high-rise or high-density residential buildings; they create a similar effect of a strong sense of security and neighbourliness (Bay et al., 2006). Fig. 55 Kampong house with veranda Source: Bay et all, 2006

Fig. 56 Kampong house veranda diagram Source: Bay et al., 2006

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Fig. 57 Forecourts on Bedok Court Condominium Source: Ply-Studio, 2008

Table. 1 Semi-open space and social effects Source: Bay et al., 2006

These semi-open spaces are called forecourts. The Bedok Court condominium was one of the last few residential buildings which featured sky streets and forecourts to create the sense of land settlement on highrise buildings before the change in building and housing regulations in 1986 which immediately discouraged developers from providing these types of spaces. The forecourts do not only reinforce the sense of community, but as the spaces are occupied by vegetation, it also enhances the quality of life which is missing in the case of high-rise and high-density living. Having lush plants could help decrease ambient temperatures in the surrounding area as shown in Table 1.

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3.2.2 The Punggol Eco Town The Punggol Eco-town is a recent development by HDB. The first phase sale, Punggol Northshore, was launched in 2015 and is currently under construction. The smart home concept does not only include home automation and convenience at oneâ&#x20AC;&#x2122;s fingertips, but it also introduces more sustainable features such as: 1) Remote metering and monitoring of electricity usage and maintenance status 2) Movement sensors and led lighting in common area 3) Rain harvesting system 4) Photovoltaic panel 5) Waste management system 6) Local public transportation system with low energy and low carbon vehicles. This system includes an intelligent bicycle rental system. The design also portrays many sustainable design strategies. The orientation of all buildings is facing a north-west direction toward the coast to catch the wind and avoid solar gain from the direct east and west directions. Additionally, the stripe buildings layout gives all units a uniform thermal performance. Vertical and horizontal shading devices such as hollow brick panels and grills are used widely in the project. The ground level is used for multiple functions such as gardens, community activities, and recreational activities providing quality of life for the residents.

Fig. 58 Northshore Residences Source: HDB, 2015

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3.2.2 Josai LT Share House This selected case study might not provide a valuable direct lesson regarding environmental sustainability; however, it gives lessons on efficient space management. The Josai LT share house, designed by Naruse Inokuma Architects, is located in Nagoya-Shi, Japan. The house is an excellent example of how to integrate public and private interior space using spatial configuration to encourage more connection and communication between the residents. The common area is visually connected while still providing enough sense of ownership for the inhabitants to use them for different activities at the same times.

Fig. 59 LT Josai Share House Source: Naruse Inokuma Architect, 2013

The design emphasises the common space over the private space; hence the bedrooms are small. The size of the bedrooms is merely 12.4m2 which fulfils the need yet still provides flexibility. The design of the shared house with space management makes a wise step to follow the principles of micro-living since Japan, similar to Singapore, is also facing a limited land situation.

RETHINKING HDB FLAT : Applicable Design of Public Housing in Singapore

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4. FIELDWORK 4.1 SCOPE AND AREA OF STUDY 4.2 THE HDB FLAT COMMUNITY 4.3 FIELDWORK 4.4 SUMMARY

RETHINKING HDB FLAT : Applicable Design of Public Housing in Singapore

CHAPTER 4. FIELDWORK 4.1 SCOPE AND AREA OF STUDY Fig. 60 Studied flats locations

A B C D

Fieldwork was performed in four existing flats to study how occupants used the spaces and the problems that occurred in the current model of HDB flats. The fieldwork cases were chosen from the Tampines hub area as the urban growth is quicker in this quarter in comparison to Jurong and Woodland sections which are closer to the industrial zone. Figure 60 shows the location of all studied flats on the following streets: 1) Flat A: Pasir Ris Street 71 2) Flat B: Pasir Ris Street 11 3) Flat C: Pasir Ris Street 13 4) Flat D: Bedok North Road The fieldwork data was collected by two means, first, spot measurements which were performed in all examples and second, data recording which was done only on Flat A. The data collected included temperature, relative humidity, wind speed, and lighting levels. Moreover, interviewed occupants pointed out what they think are the problematic issues. The opinions of the researcher were also noted with an additional discussion with a regular guest of all the studied flats. Tampines Regional Centre is one of the three regional centres which were planned to become commercial hubs in 2030 according to the latest Singapore urban concept plan. Most of the buildings in the Tampines area is currently residential; however, shopping malls and commercials sites are starting to appear. up. The draft for the master plan 2013 pamphlet describes Tampines as one of the most visited retail and leisure stops in Singapore. Moreover, as it is already home to a large part of the population in the east, Tampines is planning to develop further new accommodation, shopping facilities, more parkland and additional amenities, especially in Tampines North. This development includes new rail routes which will grant residents and visitors more comfortable and convenient commutes.

Fig. 61 Tampines as planed in Master Plan Draft 2013 Source: URA, 2013

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4.2 THE HDB FLAT COMMUNITY The relationship between members of HDB flat community, even though, is not as tight as it was in the past, but it could still be seen clearly how the provided amenities improved the residentâ&#x20AC;&#x2122;s quality of life and enhanced the neighbourliness. As the social context changes, these public facilities have become underused. The meeting spaces on the ground floor are usually spotted once in a while to be occupied by the older generations chatting or playing chess but often times they are deserted. To revive the community spirit, problems should be accurately identified.

Fig. 62 Typical ground floor areas usage of HDB flats

The fieldwork showed that the playground and sports ground are well used and comfortable with shade from trees, but the ground floor space area under the buildings do not have sufficient lighting. Also, the seating is limited and not comfortable.

Dark

Limited activities and seats

Store

Covered walkway and a day care

Playground

Garden 44

RETHINKING HDB FLAT : Applicable Design of Public Housing in Singapore

4.3 FIELDWORK 4.3.1 Flat A: Pasir Ris Street 71 A

Wall

Floor

Ceiling

Glazing

Curtain

Material: Rendered and Painted Single Brick

Material: White granite on concrete slab

Material: Rendered and Painted concrete slab

Material: Frosted single glazing 0.3 mm

Material: Double leyer fabric

U -Value: 1.25 W/m2K

U -Value: 3.1 W/m2K

Opacity: 0-20%

Fig. 63 Flat A - Exterior view

Fig. 64 Flat A - Materiality

Flat A is originally a four-room flat which provides a joined living and kitchen area and three bedrooms. Currently, Flat A has been modified and turned into a shared four bed unit with joined kitchen and living room. The flat holds four occupants from different careers and backgrounds. Three out of the four tenants work on a routine basis with switchable weekly days off while the fourth works as aircrew, hence the non-routine lifestyle. The occupants reported the flat to have adequate ventilation to feel sufficiently comfortable in the living area but only when both living room and kitchen windows are opened. The bedrooms were reported to be comfortable most of the time, however, on some occasions, they get damp. The dampness causes a mild shocking effect from short circuits via the floors and walls. The owner of the flat installed opaque films on all windows which seem to benefit the tenants by providing cooler indoor conditions but, according to the occupants, it became necessary to turn on the artificial lights at any time of the day.

Fig. 65 Flat A - Interior views

MArch SED 2016

Date : Time :

11 Oct 2016 16:20

Sky Condition : Outside DB : Outside RH : Wind V : 1.0 m/s Illuminace : Feel like : Type : Bedroom no. : Occupant no. :

Fan off: T : 30.1 °C RH: 59 % V: 0.00 m/s Feeling: Stuffy

31.3 °C 54.5%

8000 Lux Cloudy/Windy 4 rooms flat 3 4

Keys information from occupants - Acceptable ventilation if open both living room door and kitchen windows - Need to turn on light both day and night time

lux

Fan off: T : 31.0 °C RH: 52 % V: 0.2 m/s Feeling: Comfortable

2 Fan off: T : 31.0 °C RH: 57.2 % V: 0.0 m/s Feeling: Stuffy

Illuminance Level Ceiling Fan Portable Fan

Fig. 66 Flat A - Sport measurement data

Fig. 67 Flat A - Daylight Availability After : DIVA, 2016

Data logger location

1 1600

Gross area :

100 m2

Living room : 25.2 m2 MBR : 13.9 m2 BR1 : 12 m2 BR2 : 12.4 m2 BR3 : 9.1 m2 Kitchen : 15.9 m2

The recorded data shown in Figure 66 that the indoor temperature and relative humidity are significantly lower than the kitchen and the living area. This effect might be created by the occupant who reported that even though the windows are always kept ajar, the curtain, on the other hand, is never opened. The joined shared space thermal conditions are almost identical while there is some occurrence of peaks of the humidity levels in the kitchen due to the occupants’ activities.

Fig. 68 Flat A - Original plan

Potential Glare

%Occupied Hours 0

83 100

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In comparison to the outdoors, the indoor temperature is clearly steady and uncoupled with the outdoor, especially in the community space where the range of temperature is always at the upper edge of the comfort band. There are definite periods of air-conditioner use in the bedroom, but interestingly the air-conditioners only decrease the temperature to around 27Â°C while the thermostat is reportedly set at 25Â°C. The occupant admitted knowing the poor performance of the bedroom air-conditioners. An analysis of the original layout indicates satisfactory useful daylighting levels with some potential glare, however, the opaque films which were put on the glazing hinders the supposed good daylighting performance.

MArch SED 2016

Average of 001 Temperature Average of 002 Temperature Average of 003 Temperature Average of Out Temperature Average of 001 Humidity Average of 002 Humidity Average of 003 Humidity Average of Out Humidity

100

90 85 80 75 70

Values

Average

Out Humidity

Average

45 40 35 30

F 2016-07-08

Date Values Time

S 2016-07-09

S 2016-07-10

M 2016-07-11

T 2016-07-12

W 2016-07-13

T 2016-07-14

F 2016-07-15

S 2016-07-16

19:00

14:00

09:00

04:00

23:00

18:00

13:00

08:00

03:00

22:00

17:00

12:00

07:00

02:00

21:00

16:00

11:00

06:00

01:00

20:00

15:00

10:00

05:00

00:00

19:00

14:00

09:00

04:00

23:00

18:00

13:00

08:00

03:00

22:00

17:00

12:00

07:00

02:00

21:00

16:00

11:00

06:00

01:00

20:00

15:00

10:00

05:00

00:00

S 2016-07-17

Average of 001 Temperature Spot1 Temperature

[Bedroom] (째C) [Living room] (째C) Average of 003 Temperature Spot3 Temperature [Kitchen] (째C) Average of Out Temperature Outdoor Temperature (째C) Average of 001 Humidity Spot1 RH [Bedroom] (%) Average of 002 Humidity Spot2 RH [Living room] (%) Average of 003 Humidity Spot3 RH [Kitchen] ((%) Average of Out Humidity Outdoor RH (%) Average of 002 Temperature Spot2 Temperature

2016-07-16

19:00

14:00

09:00

04:00

23:00

18:00

13:00

08:00

03:00

Fig. 69 Flat A - Data loggers recorded data

2016-07-17

RETHINKING HDB FLAT : Applicable Design of Public Housing in Singapore

4.3.2. Flat B: Pasir Ris Street 11 B

Wall

Floor

Ceiling

Glazing

Curtain

Material: Rendered and Painted Single Brick

Material: Black granite on soncrete slab

Material: Rendered and Painted concrete slab

Material: Single glazing 0.3 mm

Material: Opaque Fabric

U -Value: 1.25 W/m2K

U -Value: 3.1 W/m2K

Opacity: 5%

Flat B is originally an executive unit which provides a living room with study area, kitchen, and three bedrooms; the flat has currently been modified by combining the study area with the master bedroom. Flat B has four occupants in total all working with non-routine schedules. The residents revealed that the spacious living area has poor ventilation hence the space is hot most of the time, particularly with temporary sun penetration. Moreover, the tenants say that having electric fans is highly essential. According to the observation, while there is good ambient daylight from outside, the daylight distribution to the kitchen, which requires good lighting, is poor. The factor that causes the space to be uncomfortably hot could be the orientation and lack of shading devices. The living room windows face west with 50 centimetres overhang; this setting may not be adequate as the solar radiation comes from a high angle. Also, the lack of shading device means the space is unprotected from the sunâ&#x20AC;&#x2122;s penetration which could heat up the area. Converting the study area into the master bedroom also negatively affects the internal wind flow by blocking the design intent cross ventilation.

Fig. 70 Flat B - Exterior view

Fig. 71 Flat B- Materiality

Fig. 72 Flat B - Interior views

MArch SED 2016

Date : Time :

6 July 2016 16:00

Sky Condition : Outside DB : 34.7 °C Outside RH : 54.2 % Wind V : 0.06 m/s Illuminace : ~20000 Lux Feel like : Hot and Sweaty Type : Bedoom no. : Occupant no. :

Ceiling Fan

Portable Fan

Fig. 73 (Above) Flat B - Spot measurement data Fig. 74 (Left) Flat A - Daylight Availability After : DIVA, 2016

Fan off: T : 31.2 °C RH: 62.2 % V: 0 m/s Feeling: Hot

2000

680 55 189

116

213

Ceiling Fan

2000

545

Executive Flat 3 4

Keys information from occupants - Poor ventilation - Solar radiation penetration - Feel hot most of the time - Fan on @ all occupant time

lux

Fan on: T : 31.6 °C RH: 60.7 % V: 1.0 m/s Feeling: Neutral Fan off: T : 31.6 °C RH: 62.2 % V: 0.0 m/s Feeling: Hot

Gross area : 147 m2 Living room : 53.9 m2 MBR : 34.7 m2 BR1 : 13.6 m2 BR2 : 16 m2 Kitchen : 16.5 m2

The window’s design seems to play a role in the low daylighting performance. The dining area contains only narrow and high windows which cannot provide good daylight distribution at working surface level. As a result, the use of this multi-purpose space is not efficient.

Fig. 75 (Right) Flat A - Original plan

Potential Glare

%Occupied Hours 0

83 100

RETHINKING HDB FLAT : Applicable Design of Public Housing in Singapore

4.3.3 Flat B: Pasir Ris Street 13 C

Wall

Floor

Ceiling

Glazing

Curtain

Material: Rendered and Painted Single Brick

Material: White granite on concrete slab

Material: Rendered and Painted concrete slab

Material: Single glazing 0.3 mm

Material: Translucent fabric (White)

U -Value: 1.25 W/m2K

U -Value: 3.1 W/m2K

Opacity: 30%

Fig. 76 Flat C - Exterior view

Fig. 77 Flat C - Materiality

Flat C is the most common type of HDB flat, a four-room unit which provides three bedrooms and a joined area which includes living, dining, and kitchen area. Flat B occupies three renters in total all working with non-routine schedules. The residents describe the unit as having excellent ventilation when the living room windows are opened on both sides. Despite the assumed lower ventilation rate, all occupants confirm feeling comfortable in their bedrooms. Different from the other examples, tenants from Flat C seem to use the shared space more often. The interview revealed that while using the shared space, the occupants usually feel comfortable with portable fans and sometimes the area is adequately comfortable without the fans. The daylighting performance too is reported as satisfactory; however, it could be seen from the observation that the dining area was considerably darker and the light in this area had to be turned on while in use.

Fig. 78 Flat C - Interior views

MArch SED 2016

Date : Time :

7 July 2016 16:50

Sky Condition : Outside DB : 30.5 °C Outside RH : 66.6 % Wind V : 5.50 m/s Illuminace : ~12000 Lux Feel like : Windy Type : Bedroomno. : Occupant no. :

4 rooms flat 3 3

Keys information from occupants - Good ventilation if open both living door and window - Poor ventilation if the entrance door is closed - Comfortable in bedrooms - Fans are used often but not all the time lux

Fan on: T : 29.7 °C RH: 65 % V: 0.5 m/s Feeling: Comfortable

760 2000 100

450

100

260

Fan off: T : 30.5 °C RH: 65 % V: 0.4 m/s Feeling: Comfortable Gross area : 100 m2 Living room : 53 m2 MBR : 15.7 m2 BR1 : 12 m2 BR2 : 12 m2

Illuminance Level Ceiling Fan Portable Fan

Fig. 79 (Above) Flat C - Spot measurement data

Fig. 80 (Left) Flat C - Daylight Availability After : DIVA, 2016

The key to a comfortable indoor environment seems to be the orientation of the flat which has its windows facing north and south plus the available cross ventilation without obstruction. Furthermore, the reason that Flat C appears to favour its occupants more might be just because the apartment is used in the way it was designed to without modification. The solution to getting residents to use the common space might be simple, as seen in Flat C, by providing the users with thermal comfort and good daylighting performance.

Fig. 81 (Right) Flat C - Original plan

Potential Glare

%Occupied Hours 0

83 100

RETHINKING HDB FLAT : Applicable Design of Public Housing in Singapore

4.3.4. Flat D: Bedok North Road D

Wall

Floor

Ceiling

Glazing

Curtain

Material: Rendered and Painted Single Brick

Material: White granite on concrete slab

Material: Rendered and Painted concrete slab

Material: Single glazing 0.3 mm

Material: Opaque Fabric

U -Value: 1.25 W/m2K

U -Value: 3.1 W/m2K

Opacity: 5%

Fig. 82 Flat D - Exterior view Source: Google Inc, 2017

Fig. 83 Flat D - Materiality

Flat D is a five-room unit which provides three bedrooms, a joined living-dining area, and a kitchen. In comparison to the other selected models, the layout of Flat D is unique with a compound shaped design. This arrangement causes the windows and the exposure of the external wall of each room to be facing different directions. Some of the windows on the west and north-west side of the unit open into a narrow and tall courtyard. Flat D is occupied by three renters in which all work with nonroutine schedules. The occupants reported the unit to be stuffy. This problem is unmistakably a result of another issue learned from the interview that the apartment has poor ventilation. The poor ventilation rate happens even when the entrance door, kitchen windows, and living room windows are all opened, however, the situation improves when all doors and windows including those of the bedrooms are opened, but only to a tolerable level.

Fig. 84 Flat D - Interior views

MArch SED 2016

Date : Time :

15 July 2016 20:00

Sky Condition : Outside DB : 28 Â°C Outside RH : 77.5 % Wind V : 2.20 m/s Illuminace : Feel like : Wet and Sweaty Type : Bedroomno. : Occupant no. :

5 rooms flat 3 3

Keys information from occupants - Poor ventilation although entrance door, kitchen windows and living room windows are opened - Acceptable ventilation when open all doors and windows. lux

Illuminance Level Ceiling Fan Portable Fan

Fig. 85 Flat D - Spot measurement data

Gross area :

Fan on: T : 27.8 Â°C RH: 77.5 % V: 0.4 m/s Feeling: Hot and Stuffy

110 m2

Living room : 38 m2 MBR : 17.8 m2 BR1 : 12.3 m2 BR2 : 11.9 m2 Kitchen : 12.4 m2

The cause of the low ventilation rate issue could be simply identified as the layout of the flat which creates too many obstacles which could slow down the wind speed. The daylighting analysis shows that all the room may have severe glare problem which could be caused by the arbitrary orientation of the rooms. This issue requires different types of shading devices to resolve the problem, none of which are provided.

Fig. 86 Flat D - Daylight Availability After : DIVA, 2016

Potential Glare

%Occupied Hours 0

83 100

RETHINKING HDB FLAT : Applicable Design of Public Housing in Singapore

4.4. SUMMARY Table 2 illustrates the analysed results of the performance of each flat in each. The lessons learned from the existing HDB flats can be summarised as following: 1) Open plan and uncomplicated shaped layout allow proper ventilation 2) Cross ventilation should be applied 3) North and south orientation improve the thermal performance 4) Shading device is required 5) Ventilation flow between spaces would help to resolve stuffiness 6) To reduce glare, the strategy should be carefully applied to not cause a lack of lighting instead.

● ● ● ●

FAIR PERFORMANCE

POOR PERFORMANCE

GOOD PERFORMANCE

Dark most of the day = Frosted glass

● ● ● ●

WIND FLOW PERFORMANCE OCCUPANT THERMAL COMFORT OCCUPANT DAYLIGHT COMFORT OCCUPANT COMMENT ON MOISTURE PROBLEM

POOR PERFORMANCE

VERDICT

Bad wind flow = obstruction

Bad wind flow = Layout

PROBLEMS AND CAUSES

Hot = of solar gain

Stuffy = Bad wind flow

Dark = Small window in required area

Table. 2 Summary of fieldwork study

MArch SED 2016

RETHINKING HDB FLAT : Applicable Design of Public Housing in Singapore

MArch SED 2016

5. ANALYTIC WORK 5.1 OBJECTIVES 5.2 PARAMETRIC STUDY

RETHINKING HDB FLAT : Applicable Design of Public Housing in Singapore

CHAPTER 5. ANALYTIC WORK 5.1 OBJECTIVES The main purpose of the analytic work is to get a better understanding of how each test parameters affect the thermal and daylighting performance and to what extent the test parameters affect the thermal and daylighting performance. As a result, the outcome of these parametric simulations will provide sufficient information to deliver the best combination to create a good design or to weigh the options when designers need to compromise with any restrictions that hinder the best parameters to be used. The analytic work is divided into three sections and each section adopts different tools. First, the thermal section is studied which is based on thermal model simulations on Openstudio and Energy Plus. The second section, the daylighting performance test, was done on the DIVA application on a Rhinoceros platform. Lastly, the shading devices study was done using Honeybee and Ladybug plugin on Grasshopper for Rhinoceros platform. The tested parameters included:

1) Ventilation periods 2) Window to floor ratio 3) Depth of layout 4) Different shading application (overhang, vertical and horizontal fins and laths) 5) Ceiling height 6) Opening height and proportion

As to be able to compare the number of parameters, the majority of the thermal test results were recorded in a sensible cooling rate and moisture load to dehumidifying rate instead of a comparing temperature graph. However, the case of different ceiling height was compared using a temperature chart because the volume differences made the cooling and dehumidifying rate count inaccurate. Moreover, the cases were sub-divided into two types of space: cross ventilation space which is common for living rooms, and single-sided ventilation which is more likely for bedrooms. The daylight autonomy at 300 lux was tested in different cases to determine which setting provided adequate daylight levels and which does not. The incidental solar radiation on the surface was simulated on the windows to observe the effect of heat gain from different types of shading. The base setting for all cases, unless otherwise stated, is 8 m2 for living room and 6 m2 for bedroom, square-shaped floor area, 30% window to floor ratio, ventilation at occupied hours with 50% opening factor. Base case materials are plastered and painted brick walls, concrete floor with granite finishing, and single glazed windows.

MArch SED 2016

5.2 PARAMETRIC STUDIES 5.2.1 Ventilation period The chart in Figure 87 shows that the longer period spaces are ventilated, the lower cooling rate they consume. On the other hand, the more hours they are ventilated, the more humid they are. This information indicated that the control mode of ventilation should be carefully designed to maximise usersâ&#x20AC;&#x2122; comfort. Fig. 87 Parametric thermal study result : Ventilation period After : Openstudio and Energyplus, 2017

Living Room

Bedroom

5.2.2. Window to floor ratio The window to floor ratio affects the thermal performance of the space slightly by benefiting the single-sided ventilation while the opposite effect happens in cross-ventilated space. Clearly, it could be seen that the higher the window to floor ratio, the spaces are getting more humid. This issue could be a result of the inlet moisture and leakage. The daylighting analysis shows that without a shading device, a 20% to 30% window to floor ratio appears to favour the space the most by providing enough daylighting levels while not creating a critical glare problem. The outcome pointed out that the window to floor ratio should be kept at the optimum level to avoid the impact of inlet heat, moisture, and glare problems. Fig. 88 Parametric thermal study result : Window to floor ratio After : Openstudio and Energyplus, 2017

Living Room

Bedroom

RETHINKING HDB FLAT : Applicable Design of Public Housing in Singapore

Living Room

Table. 3 Parametric daylight study result : Window to floor ratio After : DIVA, 2017

Bedroom

10%

20%

10%

20%

30%

40%

30%

40%

%Occupied Hours 0

83 100

5.2.3. Depth of layout and orientation The thermal analysis confirms that the favourable orientation is north and south for cross ventilation spaces and south for spaces with single-sided ventilation. Moreover, the shallow layout is suitable for the single-sided windowâ&#x20AC;&#x2122;s as it provides good thermal and daylight distribution while, on the other hand, the deep plan layout is preferable for cross ventilated spaces. The simulation also proves that the second most preferable orientations are diagonal directions while orienting spaces to the immediate east or west is to be avoided. Living Room : Deep and Shallow Layout

Fig. 89 Parametric thermal study result : Living room Layout and Orientation After : Openstudio and Energyplus, 2017 Living Room : Square Layout

Table. 4 Parametric daylight study result : Living room Layout and Orientation After : DIVA, 2017 %Occupied Hours 0

DEEP PLAN

SHALLOW PLAN

N-S

E-W

N-S

E-W

N-S

E-W

NW-SE

NE-SW

NW-SE

NE-SW

NW-SE

NE-SW

83 100

MArch SED 2016

Bedroom : Deep and Shallow Layout

Fig. 90 (Above) Parametric thermal study result : Bedroom Layout and Orientation After : Openstudio and Energyplus, 2017

Bedroom

Table. 5 (Left) Parametric daylight study result : Bedroom Layout and Orientation After : DIVA, 2017

DEEP PLAN

Bedroom : Square Layout

%Occupied Hours 33

83 100

DEEP PLAN

RETHINKING HDB FLAT : Applicable Design of Public Housing in Singapore

5.2.4. Different shading application First, the thermal study shows that the 2-metre overhang works the best for all orientations while it does not have any noticeable impact on indoor humidity. The more detailed shading study using simulations of incidental solar radiation on vertical surfaces shows that the size of overhang plays a significant part protecting indoor spaces from solar radiation. The other shading devices such as the horizontal fin, vertical fins, and laths also decrease the amount of heat on the surface significantly. The daylight autonomy confirms that combining the best options based on the thermal and solar incident simulations could provide adequate daylight levels with good distribution. The combination of shading devices of the final cases are 2 metres overhang, horizontal fins, 1.5-meter width vertical fins, and vertical laths Living Room N-S

E-W

NW_SE

NE-SW

Fig. 91 Parametric thermal study result : Living room shading (overhang) After : Openstudio and Energyplus, 2017

MArch SED 2016

Fig. 92 Parametric thermal study result : Bedroom shading After : Openstudio and Energyplus, 2017

Bedroom N

Fig. 93 Parametric Study : Shading Devices After: Honeybee and Ladybug, 2017

Horizontal Lath

Vertical Lath

Vertical Fin on Baclcoy 1.5m

Vertical Fin on Baclcoy 1.0m

Vertical Fin on Baclcoy 0.5m

Horizontal Lath

Vertical Lath

Vertical Fin on Baclcoy 1.5m

Vertical Fin on Baclcoy 1.0m

Vertical Fin on Baclcoy 0.5m

Horizontal Fin

Horizontal Lath

Vertical Lath

Vertical Fin on Baclcoy 1.5m

Vertical Fin on Baclcoy 1.0m

Vertical Fin on Baclcoy 0.5m

Horizontal Fin

Overhang 2.0 m

Horizontal Lath

Vertical Lath

Vertical Fin on Baclcoy 1.5m

Vertical Fin on Baclcoy 1.0m

Vertical Fin on Baclcoy 0.5m

Horizontal Fin

Overhang 2.0 m

1.06 0.861 0.719 0.67 0.849 0.78 0.745 0.479 0.48

Horizontal Fin

Overhang 2.0 m

Overhang 1.5 m

1.19 0.918 0.734 0.69 0.904 0.848 0.782 0.511 0.521

Overhang 2.0 m

Incident Solar Radiation on Windows Surface : North-East NW

Overhang 1.5 m

Incident Solar Radiation on Windows Surface : North-West 0.97 0.825 0.694 0.649 0.812 0.759 0.702 0.468 0.465

Overhang 1.5 m

Incident Solar Radiation on Windows Surface : East Overhang 1.0 m

Incident Solar Radiation on Windows Surface : North NE

Overhang 1.0 m

1.25 0.94 0.748 0.7 0.927 0.87 0.805 0.517 0.531

Overhang 1.0 m

Horizontal Lath

Overhang 1.0 m

Horizontal Lath

Vertical Lath

1.576 1.213 0.911 0.857 1.204 1.162 1.12 0.56 0.631

Horizontal Lath

Vertical Lath

Horizontal Lath

Vertical Lath

Vertical Fin on Baclcoy 1.5m

1.103 0.973 0.833 0.765 0.964 0.925 0.887 0.454 0.528

Vertical Lath

Vertical Fin on Baclcoy 1.5m

Vertical Fin on Baclcoy 1.0m

0.799 0.69 0.605 0.569 0.67 0.626 0.579 0.378 0.399

Vertical Fin on Baclcoy 1.5m

Vertical Fin on Baclcoy 1.0m

Vertical Fin on Baclcoy 0.5m

Vertical Fin on Baclcoy 1.0m

Vertical Fin on Baclcoy 0.5m

Horizontal Fin

Overhang 2.0 m

Overhang 1.5 m

Overhang 1.0 m

0.828 0.713 0.625 0.588 0.69 0.642 0.594 0.388 0.415

Vertical Fin on Baclcoy 1.0m

Vertical Fin on Baclcoy 0.5m

Horizontal Fin

Overhang 2.0 m

Overhang 1.5 m

Overhang 1.0 m

Vertical Fin on Baclcoy 0.5m

Horizontal Fin

Overhang 2.0 m

Overhang 1.5 m

Overhang 1.0 m

Base (30%WF 1mOverhang) Overhang 1.5m Overhang 2.0m Horizontal Fin Vertical Fin on Balcony End 0.5m Vertical Fin on Balcony End 1.0m Vertical Fin on Balcony End 1.5m Lath Vertical Lath Horizontal

Horizontal Fin

Overhang 2.0 m

Overhang 1.5 m

Overhang 1.0 m

RETHINKING HDB FLAT : Applicable Design of Public Housing in Singapore

Incident Solar Incident on vertical surface [kW/m2] Table. 6 Parametric study result : Shading After: Honeybee and Ladybug, 2017

Incident Solar Radiation on Windows Surface : South

Incident Solar Radiation on Windows Surface : West

Incident Solar Radiation on Windows Surface : South-East

Incident Solar Radiation on Windows Surface : South-West

MArch SED 2016

Chart Title

5.2.5. Ceiling Height In addition Chart Title to the base configuration, vertical fins and laths were applied to the thermal model to study the impact of the alteration of the ceiling height. The test was done only on the living room model as bedrooms do not usually adopt double-height design. Figure 94 shows that the temperature in double height space is lower when the outdoor temperature is already low, but when the outdoor condition is high, the double height space is not significantly cooler. Besides, the favourable effect is only at a trivial level compared to the space with a high ceiling. The space with 2.6 metres height ceiling always performed the worst and conclusively should not be employed.

Fig. 94 Parametric thermal study result : Ceiling Height 30 After : Openstudio and Energyplus, 2017

Therefore, it could be concluded from the simulation result that the medium height ceiling from 3 to 4 metres should be of the most advantage to the occupants. Chart Title

40 40

35 35

Site

2.4m Ceiling (Minimum) THERMAL ZONE: 2.6:Zone Air Temperature [C](Hourly)

THERMAL ZONE: 3.0:Zone Air Temperature [C](Hourly)

4.0 Ceiling ZONE: 4.0:Zone Air Temperature [C](Hourly) THERMAL

THERMAL ZONE: 6.0 LOFT:Zone Air Temperature [C](Hourly)

Table. 7 Parametric daylight study result : Ceiling Height After : DIVA, 2017

Window Height 3m

%Occupied Hours 0

83 100

Potential glare

06/21 01:00:00 06/18 19:00:00

06/20 22:00:00 06/18 16:00:00

06/21 22:00:00

6.0m Ceiling (Double THERMAL ZONE: Height) 6.0 LOFT:Zone Air Temperature [C](Hourly)

THERMAL ZONE: 6.0 LOFT:Zone Air Temperature [C](Hourly)

06/20 19:00:00 06/18 13:00:00

3.0m Ceiling THERMAL ZONE: 3.0:Zone Air Temperature [C](Hourly) THERMAL ZONE: 4.0:Zone Air Temperature [C](Hourly)

THERMAL ZONE: 3.0:Zone Air Temperature [C](Hourly)

06/20 16:00:00 06/18 10:00:00

06/21 16:00:00

06/21 10:00:00

SAT

06/20 13:00:00 06/21 19:00:00 06/18 07:00:00

06/21 13:00:00 06/20 10:00:00 06/18 04:00:00

06/21 04:00:00

06/21 07:00:00 06/20 07:00:00 06/18 01:00:00

THERMAL ZONE: 2.6:Zone Air Temperature [C](Hourly)

06/21 01:00:00 06/20 04:00:00 06/17 22:00:00

06/20 13:00:00

FRI

06/20 19:00:00 06/20 01:00:00 06/17 19:00:00 06/20 22:00:00

06/19 22:00:00 06/17 16:00:00 06/20 16:00:00

06/20 07:00:00

06/19 19:00:00 06/17 13:00:00 06/20 10:00:00

06/20 01:00:00

06/19 16:00:00 06/17 10:00:00 06/20 04:00:00

06/19 19:00:00

Outdoor Temperature Site

06/19 13:00:00

THU

06/19 22:00:00 06/19 13:00:00 06/17 07:00:00

06/19 16:00:00 06/19 10:00:00 06/17 04:00:00

06/19 07:00:00

06/19 10:00:00 06/19 07:00:00 06/17 01:00:00

06/19 04:00:00 06/19 04:00:00 06/16 22:00:00

06/18 16:00:00

06/18 10:00:00

WED

06/18 22:00:00 06/19 01:00:00 06/16 19:00:00 06/19 01:00:00

06/18 22:00:00 06/16 16:00:00 06/18 19:00:00

06/18 19:00:00 06/16 13:00:00 06/18 13:00:00

06/18 04:00:00

06/18 16:00:00 06/16 10:00:00 06/18 07:00:00

06/17 22:00:00

06/18 01:00:00 06/18 13:00:00 06/16 07:00:00

06/17 16:00:00

06/17 10:00:00

TUE

06/17 19:00:00 06/18 10:00:00 06/16 04:00:00

06/17 13:00:00 06/18 07:00:00 06/16 01:00:00

06/17 07:00:00 06/18 04:00:00 06/15 22:00:00

06/17 01:00:00 06/18 01:00:00 06/15 19:00:00 06/17 04:00:00

Site

06/16 19:00:00

06/16 13:00:00

06/16 07:00:00

MON

06/17 22:00:00 06/15 16:00:00 06/16 22:00:00

06/17 19:00:00 06/15 13:00:00 06/16 16:00:00

06/17 16:00:00 06/15 10:00:00 06/16 10:00:00

06/16 01:00:00

06/16 04:00:00 06/17 13:00:00 06/15 07:00:00

06/15 19:00:00

06/15 13:00:00

SUN

06/15 10:00:00 06/17 04:00:00

06/15 04:00:00 06/17 01:00:00 06/15 07:00:00

06/16 22:00:00 06/15 01:00:00

06/16 19:00:00

06/16 16:00:00

06/16 13:00:00

06/16 10:00:00

06/16 07:00:00

06/16 04:00:00

20 20

06/15 22:00:00 06/17 10:00:00 06/15 04:00:00

25 25

06/15 16:00:00 06/17 07:00:00 06/15 01:00:00

30 30

THER

RETHINKING HDB FLAT : Applicable Design of Public Housing in Singapore

5.2.6. Opening height and proportion According to the thermal analysis, the location of normal size windows shows no notable difference in thermal performance, however, as suggested in the vernacular architecture study, the body height windows help cool down the occupantsâ&#x20AC;&#x2122; bodies directly with the wind velocity. The study of window shape and location indicates different daylighting performance. The window types selected for study in this chapter are narrow horizontal and narrow vertical windows. The narrow horizontal windows at a high level show the potential to provide adequate daylight on both north-south and east-west facing models without shading device, however, in comparison to the normal height windows, the daylight distribution of narrower windows is limited. The narrow vertical windows are clearly not providing proper daylight distribution since they create blind spots on the horizontal plane. Despite the lack of performance compared to normal size windows, the narrow windows can be well used with specific functions, for example, the cases that need limited eye level or spot lighting.

Living Room

Fig. 95 Parametric thermal study result : Opening height and proportion After : Openstudio and Energyplus, 2017

Bedroom

High Narrow Horizontal Window Narrow Vertical Window

N-S

E-W

Narrow Horizontal Window

N-S

W-F

N-S

E-W

Table. 8 Parametric daylight study result : Opening height and proportion After : DIVA, 2017 %Occupied Hours 0

Potential glare

83 100

MArch SED 2016

RETHINKING HDB FLAT : Applicable Design of Public Housing in Singapore

MArch SED 2016

6. GUIDELINES 6.1 OBJECTIVES 6.2 DEVELOPMENT GUIDELINES FOR NEW FLATS 6.3 IMPROVEMENT SUGGESTION FOR EXISTING FLATS

RETHINKING HDB FLAT : Applicable Design of Public Housing in Singapore

CHAPTER 6. GUIDELINES 6.1 OBJECTIVES The successful current HDB flat model indicates the repetitive design and configurations are what led to its successful history. Despite being viewed as lacking creativity, repetition proves good practice which can be used again and further developed. The guidelines, which are the outcome of research done on this project, will remodel the HDB flats by bringing a more sustainable lifestyle and reduce the impact on the environment. The guidelines consist of two major sections, the development guidelines for new projects and the improvement suggestions for existing flats. The parametric analysis work results discussed in Chapter 5 need to be included and used simultaneously with the guidelines since the guidelines suggest the best and preferable practice as the test results will provide information to aid the designers to make decisions to overcome what hinders them in adopting the best practice. 6.2 DEVELOPMENT GUIDELINES FOR NEW FLATS 6.2.1 Outdoors Like the existing model, the ground level of the area should be designed as a public space to build a connection between the buildings and the surrounding context. The spaces which are encouraged to be occupied by various activities at different times would create movement and a sense of security for the residents. The commercial zone, if applicable, should be separated from the rest of the zones by using buffering green spaces which would not cut the commercial area off completely. The blurred edges between spaces and an intentionally designed visual connection will impact the way people use and commute on ground level by encouraging them to explore and maximise the efficiency of the spaces. Access from the street should be protected from the sun and rain with a covered walkway which branches into all building and areas. Importantly, all parts of these areas should be accessible for those with disabilities. To minimising car usage, the ratio of carparks per unit should be kept at a necessary level with occasional car renting services provided. According to the statistic9, around 30% of households own a private car; this number could be used as a reference. Disabled people will be entitled to one parking space per person while the rest could be let out to the occupants. The landscape scheme should provide as much vegetation space as possible including large size trees, shrubs, and groundcover. This greenery will provide shading and help lower the mean radiant temperature on the ground level and, as a result, make the users feel comfortable. The plantation areas should be carefully studied to ensure that enough sunlight is provided. Fig. 96 Landscape design recommendation example Source: Jones, 2008

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6.2.2 Indoor All the flat areas should be step free and wheelchair friendly. The forecourt is recommended as well as corridor garden spaces which would lower the temperature around the apartment and encourage neighbourliness. The internal area should be divided into zones which could be modified as it would provide more flexibility for different types of occupants. The preferable orientation is north-south to avoid high solar gain from the east and the west. The layout of the living rooms should be a deep plan with cross ventilation while the bedroom without cross ventilation should be shallow-plan. Moreover, ventilation between spaces which do not produce excess humidity should be provided to accelerate the ventilation rate. The recommend window to floor ratio is from 20% to 30% with the application of the moisture membrane. Furthermore, the salt dehumidifier should be installed, or as an alteration, the portable type can be used. In addition to the natural ventilation, the use of electric fans should be promoted to maintain indoor comfort; ceiling fans create more constant wind flow in the space while portable fans can supply spot cooling. Shading devices should include (Figure 97): 1) 1.5 to 2-metre overhangs which could act as a balcony 2) Horizontal Fins 3) Vertical Fins 4) Vertical Laths Importantly, changing peoplesâ&#x20AC;&#x2122; behaviour toward a more sustainable lifestyle is a crucial factor to generate a sustainable environment. The resolution of this issue, other than educating the users and raising awareness, could be the monitoring method where visible meters are installed where they are visible to the neighbourhood. Consequently, this strategy would create a competitive reaction which leads to the change of behaviour. Plus, the regulation on low energy equipment and appliances should be made and agreed on. Fig. 97 Indoor strategies diagram

RETHINKING HDB FLAT : Applicable Design of Public Housing in Singapore

6.3. IMPROVEMENT SUGGESTION FOR EXISTING FLAT 6.3.1 Outdoors The outdoor alteration for current projects should focus on boosting the usage of ground floor spaces by adding more shaded areas with seating and providing more opportunities for activities. Installing small sports accessories like table tennis tables, adding seating which is suitable for study, or holding events like crafting workshops will help revive these spaces. Additionally, light shelves or other means should be used to brighten up the spaces under the buildings to provide sufficient daylight levels and bring more liveliness into the ground floor space. The renovation of the green areas which are now underused should also be executed in the course that they provide larger varieties of typologies. Also, to convince people to help in the converting and maintaining of the areas could be strategies to boost the localâ&#x20AC;&#x2122;s sense of ownership which might, as a consequence, make the area more popular with locals. Fig. 99 Light Shelf Source: Jones, 2008

6.3.2. Indoors For the internal area, it is a vital step to adopt and employ humidity control strategies. The portable type of salt dehumidifier can be used while upgrading windows with moisture membrane application will help to reduce the internal relative humidity bringing comfort to the indoor space. Furthermore, adding ventilation to the interior doors would promote indoor air flow between spaces which would distribute the cooler air from the cooler areas and help keep the rooms cool at all times. To reduce the effects of solar heat gain, extra lightweight shading devices can be applied, for example, extendable overhangs or vertical wooden laths. Adding more lush plants around the corridor area should also reduce the impact from reflected heat and diffuse radiation.

Fig. 98 Awning Source: Jones, 2008

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Endnotes

9 Department of Statistics Singapore, 2016

RETHINKING HDB FLAT : Applicable Design of Public Housing in Singapore

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7. DESIGN APPLICABILITY 7.1 SITE ANALYSIS 7.2 PROGRAMMING 7.3 OUTDOOR 7.4 INDOOR

RETHINKING HDB FLAT : Applicable Design of Public Housing in Singapore

CHAPTER 7. DESIGN APPLICABILITY 7.1 SITE ANALYSIS The selected site is in the Bedok area on New Upper Changi Road which is a suburban area on the south edge of Tampines hub on the east side of the mainland. The main road leads directly to the city centre on the west and the airport in the east. The one kilometre radius of the surrounding area is full of resources with schools, local markets, sports centres, and most importantly, the MRT station10, Tanah Merah, and a bus stop which is located in front of the chosen location.

Fig. 100 1 kilometre radius surrouding context Site Green Space Sport Facilities Local Market School Private Residential Building

The empty area, now occupied by vegetation, is divided into two plots with a walkway cutting through the middle. The area on the west will be the designated site while the east plot will be reserved as a public park for the locals. With the resources mentioned earlier, multiple private residential buildings were built in this area in recent years, hence even though developing a new HDB flat on the site would destroy the local green space, the plot will soon be taken over by developers nonetheless. Therefore, the project intentionally proposes to maximise its green plot ratio as compensation for the green spaces taken from the neighbourhood.

Fig. 101 Site location

Site Area 33,790 Sq.m

Site

Park

MArch SED 2016

Fig. 102 Site views Source: Google Inc, 2017

RETHINKING HDB FLAT : Applicable Design of Public Housing in Singapore

The environmental analysis shows that the surrounding context does not affect the site area. Solar access and sun patch analysis indicate the site has full access to sunlight on the equinox and solstice. The wind analysis shows that the wind direction, which primarily comes from the south-west in June to September, might be diverted on to the street level to reach the site from the west. On the contrary, the wind from November to March, which mainly comes from the north, will remain north. However, although the climate analysis shows that significant portions of the wind come from the north and south-west in different seasons, the wind will still expectedly come from all directions.

Fig. 103 Site analysis : Sun Path After: Honeybee and Ladybug, 2017

MAR 21

JUN 21

Fig. 104 Site analysis : Solar Access After: Honeybee and Ladybug, 2017

DEC 21

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Fig. 105 Site analysis : Sun Patch After: Honeybee and Ladybug, 2017 Fig. 106 Site analysis : Wind Analysis After: Autodesk Flow Design, 2017

JUN to SEP

RETHINKING HDB FLAT : Applicable Design of Public Housing in Singapore

7.2 PROGRAMMING The design objectives will be to lead occupants to a more sustainable and healthier lifestyle while encouraging community spirit. The objectives also aim to provide a flexible space for Singaporeâ&#x20AC;&#x2122;s multi-cultural social context. The project also offers to provide the occupants with renewable resources such as energy, water, and food. These resource management strategies are intended to support a more sustainable and self-sufficient future for the community and the nation, which as mentioned beforehand Singapore imports a vast portion of their resources. The photovoltaic panels and rain harvesting system will be installed on the rooftop while the farm will be included in the buildings. 7.2.1 Occupantsâ&#x20AC;&#x2122; Analysis To fulfil a flexible lifestyle, two scenarios of occupant patterns were predicted and studied. The first pattern is of a regular working class single and family residents where people go to work in the morning and come back at dusk on weekdays and spend most of the weekend at home. The second pattern portrays the lifestyle of users who work on shifts and non-routine schedules where some of the occupants might stay home during the daytime on weekdays.

Table. 9 Occupant Pattern

Time 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Normal Routine

NonRoutine

Living Room Weekday Bedroom Living Room Weekend Bedroom Living Room Bedroom Living Room Weekend Bedroom Weekday

Household Size: 4 People 7.2.2 Facilities The public facilities are intended to create a good quality of life for the residents by providing all necessities and conveniences. 1) Community meeting area 2) A day care 3) A playground 4) A sports ground 5) Green spaces 6) Public multi-purpose space 7) Community car and bicycle rental 8) Commercial zone 7.2.3 Sky-Farm Urban farming in Singapore has become more popular in the last decade. More rooftop farms and corridor farms, both commercial and private, are being adopted nationwide. Factoring agriculture space into the scheme does not only supply food for the residents, but it also creates job opportunities for the elderly who are to be re-employed according to the government plan to tackle the population age balance issue. Besides, by providing jobs at home, the supposedly retired-aged workers will not have to travel far for work.

Fully Occupied Partly Occupied

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7.2.4 Structures and Materiality The project uses a prefabricated construction system with module beams and wall panels. Same as normal brick, unfired clay brick can also be made into a composited panel before shipping to the construction site. The columns spans are designed to be a six by six metre grid which would reduce the waste of material since six metres is a standard length of steel sections, steel rod, and timber sections. ROOF

Rice hull insulated concrete slab U Value 0.5 W/m2K

Unfired Clay Brick

FLOOR

Concrete and Bamboo laminate U Value 0.8 W/m2K

INTERNAL WALL

Timber

Rendered unfired clay brick U Value 1.3 W/m2K EXTERNAL WALL

Rendered unfired clay brick with shutter U Value 0.8 W/m2K STRUCTURE

Concrete

Concrete (Dense) U Value 0.6 W/m2K GLAZING

Timber

Single clear 6mm U Value 3.1 W/m2K

Fig. 107 Structure and material diagram

Lime Render

Fig. 108 Prefabricated brick panel and wall composited

Prefabricated Unfired Clay Brick Panel

kin

-S gro

din

d Cla

RETHINKING HDB FLAT : Applicable Design of Public Housing in Singapore

Fig. 109 Master Plan Concept Section

PUBLIC

BUFFER

FARM

FAR

GARDEN

COMMUNITY ACTIVITY

COMMERCIAL

COMMUNITY ACTIVITY

FARM

7.3 OUTDOOR DESIGN AND ANALYSIS 7.3.1 Massing and Master Plan All five apartment buildings stand facing north and south orientation parallel to each other and the site boundary. This building configuration will benefit all flats equally by protecting them from high solar radiation from the east and west. The farm will be located between storeys creating movement in the buildings. These voids also create a perforated effect which would allow the wind to get through. The ground level is optimised for semi-public use while still focusing on providing amenities for the community itself. All spaces are connected by a covered walkway which is accessible by foot and wheelchair. The ground floor of each building serves different purposes with several types of gardens as a buffer between them. The area on the east side next to the park is intended to be a tropical rain forest garden creating a strong relationship to the park and encouraging people to use the areas seamlessly with the park.

FOCUS ON COMMUNITY USE FOCUS ON COMMUNITY USE

FARM

FARM FARM

COMMUNITY ACTIVITY

MArch SED 2016

GARDEN

NURSERY GARDEN

SPORT GROUNDSPORT GROUND SERVICE & NURSERY & PLAYGROUD & PLAYGROUD PARKING

FARM

SERVICE & PARKING

RETHINKING HDB FLAT : Applicable Design of Public Housing in Singapore

Fig. 110 Master Plan

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pot

tal s

en cle R

Bicy

Covered Walkway

p > Sto n> Bus Statio o t T R es oM inut 2 m nutes t i 5m

rea

A ercial Comm

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F Grass

E C

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Fig. 111 Master Plan - Functions

The ground floor level of building A is a local market where the products from the sky-farm can be sold. Under Building B, a community area which seamlessly connects to the sunken gardens is ideal for various group or individual activities; residents can use this space for relaxing, playing chess, or even having a meeting. The ground floor of Building C provides a semi-open pavilion with a garden view from both sides; the pavilion space would fulfil the Malaysianâ&#x20AC;&#x2122;s need to gather for ceremonies and religious events. Under Building D a day care centre is located where residents can drop their children off before going to work; the nursery is connected to a small playground. Building Eâ&#x20AC;&#x2122;s ground floor is left open for multi-purpose use; however, this space could be regularly occupied with seating for study and workshops.

Fig. 112 Buildings Layout

RETHINKING HDB FLAT : Applicable Design of Public Housing in Singapore

Fig. 113 Building plan

Fig. 114 Building mass in relation to the sunpath After: Honeybee and Ladybug, 2017

MArch SED 2016

Fig. 115 View from the street

Fig. 116 Bird eye view

RETHINKING HDB FLAT : Applicable Design of Public Housing in Singapore

The daylighting analysis in Figure 118 confirms that most of the utilised ground areas have sufficient daylight level at 300 lux for more than 90% of the time. Fig. 117 2D Sunpath After: Honeybee and Ladybug, 2017

% occupied hours

Fig. 118 Daylight Autonomy 300 lux Ground floor spaces under the buildings After: DIVA, 2017

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MAR 21

JUN 21

DEC 21

Fig. 119 Solar Access Ground floor vegetation spaces After: Honeybee and Ladybug 2017

RETHINKING HDB FLAT : Applicable Design of Public Housing in Singapore

% occupied hours

Fig. 120 Daylight Autonomy 10,000 lux Ground floor vegetation spaces After: DIVA, 2017

% occupied hours

Fig. 121 Daylight Autonomy 5,000 lux Ground floor vegetation spaces After: DIVA, 2017

MArch SED 2016

7.3.2 Sky-Farm The daylight autonomy chart (Figure 122-123) reveals that some of the farm areas achieve five hours of 10,000 lux which is needed for the chosen plants to grow well and 5000 lux which is required to maintain a healthy growing rate.11 The more well-lit spaces could be used for fruit vegetation, while the medium lit areas can be used to grow leafy plants and herbs. The shaded areas can serve as a plant nursery, tool storage, and mushroom shed. The vegetables that can be grown on the Sky-Farm are listed as following: ● Fruit vegetation: lime, chilli, tomatoes, cucumber, melon ● Leafy vegetation and herb: basil, morning glory, coriander, asparagus ● Shaded vegetation: mushroom

Fig. 122 View from corridor to Sky-

Fig. 123 Vegetation that can be grown on Sky-Farm 92

RETHINKING HDB FLAT : Applicable Design of Public Housing in Singapore

% occupied hours

Fig. 124 Daylight Autonomy 5,000 lux Sky-Farm After: DIVA, 2017

% occupied hours

Fig. 125 Daylight Autonomy 10,000 lux Sky-Farm After: DIVA, 2017

MArch SED 2016

MAR 21

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DEC 21

Fig. 126 Solar Access Sky-Farm After: Honeybee and Ladybug 2017

RETHINKING HDB FLAT : Applicable Design of Public Housing in Singapore

7.3.3 Outdoor Comfort Analysis Figure 128-132 shows the comfort analysis at different spots on the ground floor. The result shows that most of the tested spots are comfortable most of the time which could be a result of shading from the building and vegetation.

6 5

3 4

Fig. 127 Site Plan and mPET analysis location

MArch SED 2016

Spot 1 Male (35) Height 175cm Weight 75kg

^Unconfortable Hours

Relaxing Position sitting clo. 0.2 met 1.0

1 Fig. 128 - View from the entrance : mPET spot 1 Spot 2 Male (4) Height 100cm Weight 25kg

^Unconfortable Hours

Playing Position standing clo. 0.2 met 4.0

Fig. 129 - Playground: mPET spot 2

RETHINKING HDB FLAT : Applicable Design of Public Housing in Singapore

^Unconfortable Hours

Spot 3 Male (35) Height 175cm Weight 75kg Spot 3 Male (35) Height 175cm Weight 75kg

^Unconfortable Hours

3 Fig. 130 - Basketball Court: mPET spot 3 and 4

Playing Baskerball Position standing clo. 0.2 met 7.0

Spot 4 Male (35) Height 175cm Weight 75kg

Playing Baskerball Position standing clo. 0.2 met 7.0

Resting Position sitting clo. 0.2 met 1.0

MArch SED 2016

^Unconfortable Hours

Spot 5 Male (35) Height 175cm Weight 75kg

Relxing Position sitting clo. 0.2 met 1.0

^Unconfortable Hours

Spot 6 Male (35) Height 175cm Weight 75kg

Walking in the garden Position standing clo. 0.2 met 2.4

Fig. 131 - Sunken Garden: mPET spot 5 and 6

RETHINKING HDB FLAT : Applicable Design of Public Housing in Singapore

^Unconfortable Hours

Spot 7 Male (60) Height 175cm Weight 75kg

^Unconfortable Hours

Spot 8 Male (35) Height 175cm Weight 75kg

Fig. 132 - Covered walkway: mPETspot 7 and 8

Fig. 133 - View from the bus stop and from bicycle rental stand

Playing Chess Position sitting clo. 0.2 met 1.6

Gathering Position sitting clo. 0.2 met 1.6

MArch SED 2016

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G LEVEL

Fig. 134 Sun patch analysis After: Honeybee and Ladybug, 2017

G LEVEL

FARM OPENING LEVEL

G LEVEL

FARM OPENING LEVEL

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G LEVEL

Fig. 135 Wind flow analysis After: Autodesk Flow Design, 2017 100

RETHINKING HDB FLAT : Applicable Design of Public Housing in Singapore

7.4 INDOOR DESIGN AND ANALYSIS 7.4.1 Module design

Fig. 136 Forecourt

The flat design aims to achieve flexible spaces for both families and residents sharing accommodation together. The 3-bedroom type, which is the most common type, were chosen for the reason that it is the most flexible. The 3-bedroom flats with one double bedroom, one single bedroom, and one convertible bedroom could provide 1) Home for a family with 1–2 children 2) Home for a family with a child and 1–2 elderly people 3) Shared flat for 3–4 people The new design with the forecourt covers 110 metres2 which is about the same amount of space as the existing model, excluding the balcony which is converted from the overhang. Connected to the forecourt, the common area contains the living and dining area. This furniture layout separates the living area into zones that can be occupied by different activities at the same time. The kitchen is arranged in a separate room to block the heat and moisture from cooking spreading into the joined space. The bedrooms are functional but the small size is intended to encourage the occupants to use the more spacious common area.

Fig. 137 Flexible layout diagram

110 sq. m. Family with 1-2 Children Shared Resident Family with 1 and 2 Elderly Family with 1-2 Children and 1 Elderly

101

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BEDROOM 2 MASTER BEDROOM

CORRIDOR

BEDROOM 3

BALCONY

KITCHEN

LIVING ROOM

FORECOURT

Fig. 138 Module Plan

102

RETHINKING HDB FLAT : Applicable Design of Public Housing in Singapore

Fig. 139 - Multi-function living room : View from dining area

Fig. 140 - Multi-function living room : View from living area

103

MArch SED 2016

Fig. 141 - Master Bedroom : Small but functional bedroom space

Fig. 142 - Bedroom 2 : Convertible double-single bedroom

Fig. 143 - Bedroom 3: Small but functional bedroom space

104

RETHINKING HDB FLAT : Applicable Design of Public Housing in Singapore

Fig. 144 Strategies Diagram

105

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7.4.2 Strategies All spaces would be natural ventilated 24 hours by a ventilation panel with moisture membrane located above the windows which would allow the ventilation to slowly, but constantly, get rid of hot air while preventing moisture from the outside getting in. Operable windows with adaptive moisture membrane screens are designed to be controlled by the occupants while the spaces are in use. Moreover, to accelerate the ventilation rate in the bedrooms, a ventilation panel above the bedroom doors was also applied to allow cross ventilation between indoor spaces. The overhang on both sides is 2 metres wide which would prevent direct sun penetration from a high angle, while vertical laths with horizontal fins on the top are used to decrease the effect from diffuse solar radiation. The lath elements are divided into panels which provide flexibility to open and close the middle panel as needed. The overhang space would be used as a balcony where people can also grow vegetation. Furthermore, instead of using body height openings, the ceiling fans are added to give a similar effect without losing the control of humidity. The proposed salt dehumidifier will be installed on the floor. The hygro-skin faรงade would be automatically working, stopping and allowing the moisture to buffer between the indoor and outdoor environments.

106

RETHINKING HDB FLAT : Applicable Design of Public Housing in Singapore

7.4.3 Comfort and Daylighting Analysis The simulation of the regular week shows that the operative temperature in all rooms is lower than the outside at midday when the temperature is usually the highest. More importantly, the indoor temperature is within the comfort band at all occupied times. Figure 146 shows the scenario that if the applied moisture control strategies work, the indoor humidity might be decreased by 10% from the simulation result bringing the indoor humidity much closer to the healthy range. However, in the situation where the living room is occupied at daytime on the weekday, it is still recommended to keep windows closed during that extra period and to only use the ventilation panel to maintain the control of the indoor humidity.

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0 Average of global horizontal radiation [Wh/m2]

Average of diffuse horizontal radiation [Wh/m2]

Average of wind speed [m/s]

Average of precipitable water [mm]

Average of DBT [C]

Comfort Band Range

Average of LR Temp

Average of MBR Temp

Average of BR3 Temp

Average of BR2 Temp

Fig. 145 Weekly Average Thermal Simulation Result After: Openstudio and Energy plus, 2017

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Outdoor Relative Humidity [%]

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35 Fig. 146 34 Proposed adaptation scenario Humidity level in all room 33 After: Openstudio and Energy plus, 2017

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U-Value

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Venting Schedule

Floor 0.8 W/m2K External Wall0.8 W/m2K Internal Wall 1.3 W/m2K Ceiling 1.45 W/m2K Glazing 3.1 W/m2K

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Outdoor Air Temperature [C]Humidity [%] Living Room Relative

Bedroom 2 Relative Humidity [%] MON TUE Wind Speed [m/s]

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19/10/1990

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Bedroom 3 Temperature [C]

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28 19/10/1990 21/10/1990

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Bedroom 2 Temperature [C]

Wind Speed [m/s]

DiffuseHorizontal Radiation [Wh/m2]

Global Horizontal Radiation [Wh/m2]

Fig. 147 Bedroom thermal simulation result After: Openstudio and Energy plus, 2017

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2:00 AM 4:00 AM 6:00 AM 8:00 AM 10:00 AM 12:00Wh/m2 PM 2:00 PM 4:00CPM 6:00 PM 8:00 PM 10:002:00 PM AM 12:004:00 AM AM 2:006:00 AM AM 4:008:00 AM AM 6:00 AM 10:00 8:00 AM AM 12:00 10:00 AM PM 12:002:00 PM PM 2:004:00 PM PM 4:006:00 PM PM 6:00 PM 8:008:00 PM PM 10:00 10:00 PM PM 12:00 AM AM 12:00 2:002:00 AM AM 4:004:00 AM AM 6:00 AM 6:00 8:00 AM AM 10:008:00 AM AM 10:00 12:00 PM AM 2:00 PM PM 12:00 4:002:00 PM PM 6:00 PM 8:004:00 PM PM 6:00 10:00 PM PM 12:008:00 AM PM 2:00 AM PM 10:00 4:00 AM AM 12:00 6:00 AM 2:00 AM 8:00 AM 10:004:00 AM AM 6:00 12:00 PM AM 2:008:00 PM AM 4:00 PM AM 10:00 6:00 PM 12:00 PM 8:00 PM 10:002:00 PM PM 12:004:00 AM PM 2:006:00 AM PM 4:008:00 AM PM 6:00 AM 10:00 PM 8:00 AM 12:00 10:00 AM AM 12:002:00 PM AM 2:004:00 PM AM 4:006:00 PM AM 6:00 PM 8:00 AM 8:00 PM 10:00 10:00 PM AM 12:00 12:00 AM PM 2:002:00 AM PM 4:004:00 AM PM 6:006:00 AM PM 8:00 AM 8:00 10:00 AM PM 10:00 12:00 PM PM 2:00 PM AM 12:00 4:002:00 PM AM 6:004:00 PM AM 8:00 PM 10:006:00 PM AM 12:008:00 AM AM 10:00 2:00 AM AM 4:00 AM PM 12:00 6:002:00 AM PM 8:00 AM 4:00 10:00 AM PM 12:006:00 PM PM 2:008:00 PM PM 4:00 PM PM 10:00 6:00 PM AM 12:00 8:00 PM 10:002:00 PM AM

Wh/m2

1000 25

2:00 AM 4:00 AM 6:00 AM 8:00 AM 10:00 AM 12:00 PM 2:00 PM 4:00 PM 6:00 PM 8:00 PM 10:00 PM 12:00 AM 2:00 AM 4:00Wh/m2 AM 6:00 AM 8:00CAM 10:00 AM 12:00 01:00:00 PM 09/15 2:00 PM 4:0004:00:00 PM 09/15 6:00 PM 8:0007:00:00 PM 09/15 10:00 PM 12:00 10:00:00 AM 09/15 2:00 AM 4:0013:00:00 AM 09/15 6:00 AM 8:0016:00:00 AM 09/15 10:00 AM 12:00 19:00:00 PM 09/15 2:00 PM 4:0022:00:00 PM 09/15 6:00 PM 8:0001:00:00 PM 09/16 10:00 PM 12:00 04:00:00 AM 09/16 2:00 AM 09/16 4:0007:00:00 AM 6:00 AM 09/16 8:0010:00:00 AM 10:00 AM 09/16 12:00 13:00:00 PM 2:00 PM 09/16 4:0016:00:00 PM 6:00 PM 09/16 8:0019:00:00 PM 10:00 PM 09/16 12:00 22:00:00 AM 2:00 AM 09/17 4:0001:00:00 AM 6:00 AM 09/17 8:0004:00:00 AM 10:00 AM 09/17 12:00 07:00:00 PM 2:00 PM 09/17 4:0010:00:00 PM 6:00 PM 09/17 8:0013:00:00 PM 10:00 PM 09/17 12:00 16:00:00 AM 2:00 AM 09/17 4:0019:00:00 AM 6:00 AM 09/17 8:0022:00:00 AM 10:00 AM 09/18 12:00 01:00:00 PM 2:00 PM 09/18 4:0004:00:00 PM 6:00 PM 09/18 8:0007:00:00 PM 10:00 PM 09/18 12:00 10:00:00 AM 2:00 AM 09/18 4:0013:00:00 AM 6:00 AM 09/18 8:0016:00:00 AM 10:00 AM 09/18 12:00 19:00:00 PM 2:00 PM 09/18 4:0022:00:00 PM 6:00 PM 09/19 8:0001:00:00 PM 10:00 PM

Wh/m2

FRI

SAT 100%

80%

60% m/s

8.00

6.00

4.00

2.00 0

20/10/1990

Outdoor Relative Humidity [%] Living Room Relative Humidity [%] Master Bedroom Relative Humidity [%]

THU

SAT 100%

Comfort Band 80%

800 24

60%

m/s

8.00

6.00

4.00

0 20

109

400 22

0 20

200 21

15/10/1990

16/10/1990

U-Value

Load

Venting Schedule

Floor 0.8 W/m2K External Wall0.8 W/m2K Internal Wall 1.3 W/m2K Ceiling 1.45 W/m2K Glazing 3.1 W/m2K

Outdoor Air Temperature [C] Lighting 5 Wh/m2

Living RoomOccupied Indoor Air Temperature Window hours [C] Master Bedroom Temperature [C] Ventilator 24 hours

DiffuseHorizontal Radiation [Wh/m2]

Wind Speed [m/s]

17/10/1990

Equipment Wh/m2 Global Horizontal5Radiation [Wh/m2]

18/10/1990

Fig. 149 Scenario 2 - Non-routine lifestyle : Living room thermal simulation result After: Openstudio and Energy plus, 2017

Bedroom 1 Temperature [C]

Bedroom 2 Temperature [C]

19/10/1990

20/10/1990

DiffuseHorizontal Radiation [Wh/m2]

Wind Speed [m/s]

40%

4.00

2.00

21/10/1990

Outdoor Air Temperature [C]

Indoor Air Temperature [C]

Global Horizontal Radiation [Wh/m2]

THU

09/20 10:00:00

09/20 07:00:00

09/20 04:00:00

Wind Speed [m/s]

09/20 01:00:00

DiffuseHorizontal WEDRadiation [Wh/m2]

09/19 22:00:00

200 21 09/20 10:00:00

09/20 07:00:00

09/20 04:00:00

09/20 01:00:00

09/19 22:00:00

09/19 19:00:00

09/19 16:00:00

09/19 13:00:00

09/19 10:00:00

09/19 19:00:00

09/19 07:00:00

2.00

09/19 16:00:00

40%

09/19 04:00:00

01:00:00

22:00:00

19:00:00

16:00:00

4.00

09/19 13:00:00

28 13:00:00

10:00:00

07:00:00

04:00:00

01:00:00

22:00:00

19:00:00

16:00:00

13:00:00

10:00:00

07:00:00

04:00:00

01:00:00

22:00:00

19:00:00

16:00:00

13:00:00

10:00:00

07:00:00

04:00:00

01:00:00

200 21

09/19 10:00:00

600 23 RH

09/19 07:00:00

800 24

FRI

09/19 04:00:00

400 22

THU