High-Rise Living in Asian Cities

High-Rise Living in Asian Cities

Belinda Yuen · Anthony G.O. Yeh Editors

High-Rise Living in Asian Cities

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Editors Belinda Yuen Singapore [email protected]

Anthony G.O. Yeh Centre of Urban Studies and Urban Planning The University of Hong Kong Pokfulam Road Hong Kong SAR [email protected]

Additional material to this book can be downloaded from http://extras.springer.com ISBN 978-90-481-9737-8 e-ISBN 978-90-481-9738-5 DOI 10.1007/978-90-481-9738-5 Springer Dordrecht Heidelberg London New York © Springer Science+Business Media B.V. 2011 No part of this work may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, microfilming, recording or otherwise, without written permission from the Publisher, with the exception of any material supplied specifically for the purpose of being entered and executed on a computer system, for exclusive use by the purchaser of the work. CD-ROM included in inside back cover Cover illustration: Photograph taken by Mr. John Cheuk-yee Ng. Printed on acid-free paper Springer is part of Springer Science+Business Media (www.springer.com)

Contents

1 Introduction: High-Rise Living in Asian Cities . . . . . . . . . . . Anthony G.O. Yeh and Belinda Yuen

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2 Tall Building Living in High Density Cities: A Comparison of Hong Kong and Singapore . . . . . . . . . . . . . . . . . . . . . Anthony G.O. Yeh and Belinda Yuen

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3 Physical Environment of Tall Residential Buildings: The Case of Hong Kong . . . . . . . . . . . . . . . . . . . . . . . . Stephen S.Y. Lau

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4 The Planning and Design of Environmentally Sustainable High-Rises . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Wenjian Zhu and Rebecca L.H. Chiu

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5 Garden and Ecology in the Sky . . . . . . . . . . . . . . . . . . . . Belinda Yuen

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6 Legislation and Safety of Tall Residential Buildings . . . . . . . . . Wah Sang Wong

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7 The Value of Clean Air in High-Density Urban Areas . . . . . . . . K.W. Chau, S.K. Wong, Andy T. Chan, and K. Lam

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8 Liveability of Tall Residential Buildings . . . . . . . . . . . . . . . Belinda Yuen

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9 Community Development in Tall Residential Buildings . . . . . . . Stephen J. Appold

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In the March of High-Rise . . . . . . . . . . . . . . . . . . . . . . . Belinda Yuen

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Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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Appendix (CD-ROM included inside back cover) The State of Urban High-rise Research: An Annotated Bibliography Compiled by Belinda Yuen

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Contributors

Stephen J. Appold Kenan-Flagler Business School, Kenan Institute of Private Enterprise, Kenan Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-3440, USA, [email protected] Andy T. Chan Department of Mechanical Engineering, The University of Hong Kong, Pokfulam, Hong Kong K.W. Chau Department of Real Estate and Construction, The University of Hong Kong, Pokfulam, Hong Kong, [email protected] Rebecca L.H. Chiu Department of Urban Planning and Design, The University of Hong Kong, Pokfulam, Hong Kong, [email protected] K. Lam Department of Mechanical Engineering, The University of Hong Kong, Pokfulam, Hong Kong Stephen S.Y. Lau Department of Architecture, The University of Hong Kong, Pokfulam, Hong Kong, [email protected]; [email protected] S.K. Wong Department of Real Estate and Construction, The University of Hong Kong, Pokfulam, Hong Kong Wah Sang Wong Department of Architecture, The University of Hong Kong, Pokfulam, Hong Kong, [email protected] Anthony G.O. Yeh Centre of Urban Studies and Urban Planning, The University of Hong Kong, Pokfulam, Hong Kong, [email protected] Belinda Yuen Department of Real Estate, National University of Singapore, Singapore, [email protected] Wenjian Zhu College of Architecture and Urban Planning, Shenzhen University, Shenzhen, China, [email protected]

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Chapter 1

Introduction: High-Rise Living in Asian Cities Anthony G.O. Yeh and Belinda Yuen

Hong Kong and Singapore are two Asian cities that have often been compared in terms of their urban development. Hong Kong and Singapore have the highest urban densities in the world. They are also distinguished by their high-rise housing developments and expanding tradition of high-rise living. Living in super tall residential buildings of 60 or more storeys high is increasingly quite common in Hong Kong. Although the tallest residential building is presently 40-storey, Singapore is building 50- to 70-storey housing in its city centre. This book seeks to examine the high-rise living experience of Hong Kong and Singapore.

1.1 Compact City, High Density and High-Rise Housing With increases in urban population, there is an urgent need to conserve land and reduce greenhouse gas emissions. Many urban analysts have advocated more compact urban living (see, for example, Clark, 2005; de Roo & Miller, 2000; Hall, 1996). Against growing dissatisfaction with urban sprawl, compact city policies are becoming a common development consideration in both the developed and developing countries (Jenks & Burgess, 2000; Jenks, Burton, & Williams, 1996; Salat & Majoor, 2005). Compact urban form is perceived to be a sustainable urban solution that can not only contain urban sprawl but also conserve the environment (Yeh & Li, 2000), and provide the necessary population threshold for the support of public transport (Newman & Kenworthy, 1989), especially mass transit railways. Compact cities are characterised by central area revitalisation, high-density development, mixed-use development and services and facilities such as hospitals, parks, schools, leisure and fun. Most prescriptions for high density are based on skyscrapers. Even though many people associate higher densities in residential areas with noise pollution, crime, loss A.G.O. Yeh (B) Centre of Urban Studies and Urban Planning, The University of Hong Kong, Pokfulam, Hong Kong e-mail: [email protected]

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of privacy and increased demand on infrastructure, Yeh (2000) has argued that highrise high-density urban environment if properly planned and managed may offer “good” density. Better planning, design and management can reduce the impact of high density, making the living and working environment less crowded. Tall buildings can help to mitigate some of the negative effects of high density. Urban density is the number of people living in an area, often measured by persons per square area. Building density is the percentage of land occupied by buildings. Crowdiness which is the main problem of high-density living is more related to building density and liveable space. With a fixed density, the decrease in building density may be achieved by making the buildings taller to increase the extended shared space and reduce crowding of the environment with the same amount of living space per flat (Fig. 1.1). If there is a need to increase density, some of the negative effects of the increased density (e.g. feeling of crowding and withdrawal which are manifestations of the desire for more personal space) can be reduced by building taller buildings. Theoretically, tall buildings and high density may not be directly related. The increase in the number of storeys in a building may not necessarily lead to a big increase in density if the floor area per dwelling unit increases proportionally with the increase in the number of storeys. However, most cities would increase the number of storeys without increase in dwelling area because of high land price and the need to increase urban density due to limited land. In some extreme cases such as Hong Kong there is also a decrease in dwelling area in order to make housing more affordable because of high land price. The resultant urban form is increased residential height and a big increase in the density. Clearly, not everyone is in support of increased residential height. There are debates on both the research and policy front to support and condemn taller building construction. Equally, much has been written about the myths and benefits of compact city development (see, for example, O’Toole, 2009).

Fig. 1.1 Building height and building density with same population density

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The research debate on high-rise housing largely involves investigation of the quality of life including social and health impacts of living in tall buildings. While some have pointed to the negative effects relating to concerns of children’s safety and mental health (e.g. Costello, 2005; Jephcott & Robinson, 1971; Young, 1976), others have observed that high-rise living may bring positive benefits and satisfaction such as spectacular view, privacy and quietness (see Conway & Adams, 1977; Johnson, 2002; Yuen et al., 2006). With globalization, lifestyle and technological advancement, many more are revisiting the high-rise debate and agreeing with Church and Gale (2000) that It is . . . wrong to identify tower blocks as ‘vertical slums’ and insist that they should all be flattened. Many are clearly acceptable places to live for their residents (p. 19).

The policy debate, by contrast, is more concerned with strategic policy and alternatives. The debate has come full circle. It is punctuated by initial wide support for high-rise living – that it is the ultimate, ideal, modern dwelling form (see, e.g. Helleman & Wassenberg, 2004) to intense pressure to stop this construction following evidence-based research that high-rise living is harmful to its residents and resurgence in recent decades to once again include high-rise housing in urban agenda. In Asia, high-rise public housing development has been continually used by Hong Kong and Singapore in meeting their housing needs and making their highdensity environment more liveable. In the United States and United Kingdom after the period of abandonment in the 1970s high-rise housing is once again now being built but largely by the private sector in prime urban locations. There is a similar trend in Europe and elsewhere (New South Wales Department of Planning, 2005; Turkington, Van Kempen, & Wassenberg, 2004). Whatever the desire, a change is happening; living in flats may and could increasingly become an urban norm for many more people in cities in the coming decades. The definition of tall buildings by the Council of Tall Buildings and Urban Habitat is a building of 10 storeys or more. If we use this as the definition, then the residential buildings in Hong Kong and Singapore, which are increasingly 50 or more storeys high, can be considered to be “super tall” buildings. In this sense, Hong Kong and Singapore represent the extreme cases of tall residential building environment and high urban density. Equally, the perception of tall building is not so much by the height or number of storeys but in relative terms of tallness (Yusoff, Driscoll, & Beedle, 1986). In other words, human response is a central variable in the consideration of tallness and its receptivity. Yet, in many cities, the urban revolution of high-rise housing has largely proceeded with little explicit recognition or understanding of the social context in which this form of housing is delivered or its social outcomes (Helleman & Wassenberg, 2004; O’Toole, 2009). Although Hong Kong and Singapore both have “super tall” buildings, the height of these buildings is not the same. Hong Kong on average has more and higher tall buildings than Singapore. Thus, a comparative study of Hong Kong and Singapore’s high-rise living experience can help us to better understand the development of tall buildings and high-density environment between the two cities, which have similar culture and density but different context of tall building development.

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1.2 Hong Kong and Singapore – Highest Density and Tallest Living Environment in the World Hong Kong and Singapore have the highest densities and largest amount of tall housing in the world. They offer natural settings for doing research on high-rise high-density development. The height of residential buildings in these cities has grown from the post-war 5–8 storey walkups to the present 60–70 storey buildings. Hong Kong is made up of the Hong Kong Island, Kowloon peninsular, New Kowloon, and the New Territories. The current total land area is 1,068 km2 and the population is 6.9 million, giving an overall population density of 5,385 persons per km2 . However, because of the high concentration of people living in the urban areas along the northern coast of the Hong Kong Island, Kowloon, and New Kowloon, the overall population density has highly understated the population density in Hong Kong. In the New Territories where there is less population, the population density is 2,560 persons per km2 . But, on Hong Kong Island, Kowloon and New Kowloon where the population is mainly concentrated in the limited area, the population density is 26,950 persons per km2 . In the urban area, the density can be as high as 116,531 persons per km2 such as in the Mongkok district. When the density is calculated at the street block level, some may be as high as 400,000–600,000 persons per km2 . High-density development in Hong Kong is a result of its topography, historical development and land policy. Over 75% of Hong Kong’s land consisted of hill slopes. A large proportion of the relatively flat areas are under private ownership, making development difficult (Chau, 1981). Most of the development is concentrated in Kowloon, New Kowloon, and Hong Kong Island where most of the flat land are obtained from hill levelling and land reclamation by the government. Population density in Hong Kong has increased tremendously immediately after the Second World War because of the sudden increase in population and economic activities. There was a large influx of refugees to Hong Kong after the change of regime in China in 1949. Hong Kong’s population increased from 0.6 million in 1945 to over 2 million in 1951. This led to severe housing shortage, squatting, high density and poor living environment. In terms of land policy, the government owns land in Hong Kong. Land is subdivided before leasing to the private developers through auction and tender. The government has full control over the timing, location and amount of land to be leased. The sale of land leases is one of the major sources of revenue of the government. During the property boom periods, revenue from land sales can be as high as 30% of the total revenue of the government. The control over the sale of land leases is one of the reasons for high land price in Hong Kong. The direct effect of high land price is high office and house prices, leading to high-density development and the construction of super tall residential buildings of over 60-storey. As with Hong Kong, Singapore has embarked on a programme of high-rise living to address its housing needs in recent decades. Singapore and Hong Kong share several similarities in urban characteristics and strategies and are thus often compared in urban analysis (see, for example, Castells, Goh, & Kwok, 1990;

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Ng & Hills, 2003). Singapore is a city-state with a land area of 700 km2 and a current population of 5 million. The resultant population density stands at more than 6,000 people per km2 . The density of urban built-up area is however much higher, over 9,500 persons per km2 . Even though Singapore has over 50 islands within its territorial boundary (many are being used for industry and recreation, for example, Jurong Island and Sentosa respectively), the majority of its population is located on the main island of Singapore. Against the context of limited land and increasing population, Singapore has in its urban development intensified density to meet the city’s multiple needs. The intensification is perhaps best seen in its public-led housing strategy. In order to create a highly livable city with spaces for play, Singapore in its delivery of housing has made a conscious decision to build high-rise to increase its living space. In the public sector where the bulk of its housing stock is (over 80% of its 3.4 million resident population lives in public flats), high-rise is the common dwelling form. As Wong and Yeh (1985, p. 56) explain, Physical planning and design in the HDB [Housing and Development Board, the public housing authority in Singapore] context are strongly influenced by two major considerations. First is the need to optimize scarce land resources; second is the emphasis on providing a better housing environment than that from which the residents come.

Typically laid out in comprehensively serviced new towns where no more than half of the town’s land is allocated to residential use, the gross new town density is generally in excess of 90 dwelling units per ha. Over time aided by technology advancement, building height in these towns has increased from 10-storey to more than 25-storey. However, in terms of building height, the similarity between Hong Kong and Singapore quickly evaporates. According to the Singapore Department of Statistics (2000), the majority of Singapore’s residential buildings are 12-story and below (90% of public housing and 84% of private housing). Only 0.2% of public housing and 1.3% of private housing are 25-storey or higher. Construction of 30storey public housing largely appeared in the 1990s. It is only in the past few years that construction of 40- and more storeys has started (Yuen et al., 2006). As of 2009, the tallest lived-in public housing in Singapore is 40 storeys.

1.3 High-Rise Living in Hong Kong and Singapore This book brings together a collection of papers on Hong Kong and Singapore highrise living written by urban scholars from the two cities. It attempts to illuminate the Hong Kong and Singapore high-rise development experience, in particular, the public sector-led development and contribute to the evolving evidence based literature on tall housing. While the public housing development of the two cities has received much documentation (see, for example, Castells et al., 1990; Wong & Yeh, 1985), few has focused on the significant issues surrounding the planning and development of high(er) rise.

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This book first discusses the planning and design issues of tall residential buildings. It is then followed by discussions on the legislative, economic, liveability and community aspects of tall building living. Chapter 2 by Yeh and Yuen compares tall building living in Hong Kong and Singapore. The comparative study shows that people apparently adjust to living in super tall buildings through time. It seems that when the contextual building height environment is gradually predominated by very tall buildings, people are willing to live in them and willing to live higher. People may not be accustomed to tall building living if there is only one tall building in the city. If the findings in the extreme cases of Hong Kong and Singapore have any indication, the change in the contextual environment, the appearance of more tall buildings may help increase the receptivity of tall building living. However, the change in contextual environment is but one aspect of the perceived environment. It is unlikely to bear impact if the tall building compact environment is not carefully planned, designed and managed to minimize crowdiness and maximize sustainability. The physical environment of tall residential buildings is explored by Lau in Chapter 3. It examines the place of tall building in compact city development, the shape-making architecture and its impact with examples from Hong Kong. A frequent argument in support of tall building is its role and contribution to urban sustainability. This aspect is elaborated in Chapter 4 by Zhu and Chiu. The sustainability theme is continued in Chapter 5 by Yuen who examines the opportunity at the micro scale for creating garden and ecology in high-rise development with examples from Singapore. Garden spaces provide settings for community interaction. The important issue of legislation and safety of tall residential buildings is addressed by Wong in Chapter 6. Fire and building structural safety and reliability will continue to challenge high-rise designers and developers, especially as buildings go taller, not to mention energy and material conservation. The economics of tall residential buildings is examined in Chapter 7 by Chau et al. The value of clean air in high-density urban areas is illustrated with data from Hong Kong. A major premise behind high-rise high-density living and compact development is that people living in such neighbourhoods drive less and could reduce auto-related greenhouse gas emissions. Certainly, the onset of more efficient cars and alternative fuels cannot be ignored. While technology may improve auto-performance in terms of emissions reduction, a longstanding argument of urban planning is that planning and design of neighbourhoods can help to reduce dependence on the automobile and enhance quality of life. The liveability of tall housing from a post-construction residents’ perspective is examined by Yuen in Chapter 8. Residents are the most important factor in determining whether the high-rise housing solution works. They are the people who eventually have to live with the buildings that planners, architects and developers build. Their lived experiences and impressions are issues not to be neglected. Due to its shape, placement and surroundings, high-rise housing plays a key role in the city’s built environment. Their damage and dysfunction can have profound effect on the residents and trigger ripple effect through the city (see the examples of Ronan Point and World Trade Centre). In many cases, there are building safety guidelines

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and regulations such as that explored by Wong in this volume (Chapter 6). Denser neighbourhoods have often been held up as having a stronger sense of community. Chapter 8 by Appold examines community development in tall residential buildings with data from Singapore and the United States. In the final chapter, In the March of High-rise, Yuen attempts to revisit some of the major themes and key lessons for cities in their future engagement with highrise housing development as they reinterpret development options in changing and different times. Beyond the global urban norm, an open question for each city will be, what makes a tall housing specific to the time and place in which it is set. This book is not intended to advocate that every city under population and land pressure should develop high rise building and high density environment like Hong Kong and Singapore. Rather, it demonstrates that if high density development is inevitable, good planning, development and management of high rise residential building would improve the quality of high density living. As mentioned, Hong Kong and Singapore are probably the extreme cases of high rise living. Not all cities should develop to such high densities of high rise buildings. However, appropriate increase in high rise buildings may help to make high density living more liveable. There is still plenty of room for improvement in high rise residential buildings in Hong Kong and Singapore. For example, recently in Hong Kong, there are concerns about the visual and ventilation effects and heat island impacts of high rise buildings (Ng, 2001a, 2001b). There are also concerns of the wall effects of high rise buildings that were built very close together because of low minimum building separation distance. As a result, urban design guidelines (Planning Department, 2002) and building design guidelines (Environment Bureau, 2009) were developed to further improve the visual and ventilation design of high rise buildings, hoping to create a better high-rise high-density environment. Plot ratios were also lowered in some high density areas in order to address some of the concerns of society on extreme high density development. In other words, the search for better high-rise high-density living is still going on in the two cities, hoping it will provide further guidelines and insights on how to make high-rise environment become better in the future.

References Castells, M., Goh, L., & Kwok, R. (1990) The Shek Kip Mei syndrome: Economic development and public housing in Hong Kong and Singapore. London: Pion. Chau, C. S. (1981). High density development: Hong Kong as an example. In R. Kwok, & K. S. Pin (Eds.), Planning in Asia: Present and future. Hong Kong: Centre of Urban Studies and Urban Planning. Church, C., & Gale, T. (2000). Streets in the sky: The 1st report of the national sustainable tower block initiative. London: NSTBI. Clark, M. (2005). Editorial: The compact city: European ideal, global fix or myth. GBER, 4(3), 1–10. Conway, J., & Adams, B. (1977). The social effects of living off the ground. Habitat International, 2(5/6), 595–614.

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Costello, L. (2005). From prisons to penthouses: The changing images of high-rise living in Melbourne. Housing Studies, 20(1), 49–62. Department of Statistics, Singapore. (2000). High-rise living. Singapore: Singapore Statistics Paper. De Roo, G., & Miller, D. (2000). Compact cities and sustainable urban development: A critical assessment of policies and plans from an international perspective. Aldershot: Ashgate. Environment Bureau. (2009). Building design to foster a quality and sustainable built environment: Invitation for response document. Hong Kong: Sustainable Development Division, Environmental Bureau, Hong Kong SAR Government. Hall, P. (1996). The future of the metropolis and its form. Regional Studies, 31(3), 211–220. Helleman, G., & Wassenberg, F. (2004). The renewal of what was tomorrow’s idealistic city: Amsterdam’s Bijlmermeer high-rise. Cities, 21(1), 3–17. Jenks, M., & Burgess, R. (Eds). (2000). Compact cities: Sustainable urban forms for developing countries. London: E&FN Spon Press. Jenks, M., Burton, E., & Williams, K. (Eds). (1996). The compact city: A sustainable urban form? London: E&FN Spon Press. Jephcott, P., & Robinson, H. (1971). Homes in high flats: Some of the human problems involved in multi-storey housing. Edinburg: Oliver and Boyd. Johnson, B. (2002, January). Living in high life. National Real Estate Investor. Atlanta, GA: Penton Media Inc. Accessed January 1, 2002, from http://nreionline.com/mag/ real_estate_living_high_life/ Newman, P., & Kenworthy, J. (1989). Cities and automobile dependence: An international sourcebook. Aldershot: Gower. New South Wales Department of Planning. (2005). City of cities: A plan for Sydney’s future. Sydney: Department of Planning. Ng, E. (Ed.). (2010a). Designing high-density cities for social and environmental sustainability. London: Earthscan. Ng, E. (2010b). Designing for urban ventilation. In E. Ng (Ed.), Designing high-density cities for social and environmental sustainability (pp. 119–136). London: Earthscan. Ng, M. K., & Hills, P. (2003). World cities or great cities? A comparative study of five Asian metropolises. Cities, 20(3), 151–165. O’Toole, R. (2009). The myth of the compact city (Policy Analysis No. 653). Washington, DC: CATO Institute. Planning Department. (2002). Urban design guidelines for Hong Kong: Executive summary. Hong Kong: Planning Department, Hong Kong SAR Government. Salat, W. G. M., & Majoor, S. (2005). Amsterdam zuidas european space. Rotterdam: 010 Publishers. Turkington, R., Van Kempen, R., & Wassenberg, F. (Eds.). (2004). High-rise housing in Europe: Current trends and future prospects. Delft: DUP. Wong, A., & Yeh, S. H. K. (Eds.). (1985). Housing a nation. Singapore: Maruzen Asia. Yeh, A. G. O. (2000). The planning and management of a better high density environment. In A. G. O. Yeh & M. K. Ng (Eds.), Planning for a better urban living environment in Asia (pp. 116–143). Aldershot: Ashgate. Yeh, A. G. O., & Li, X. (2000). The need for compact development in fast growing areas of China: The Pearl River delta. In M. Jenks & R. Burgess (Eds.), Compact cities: Sustainable urban forms for developing countries (pp. 73–90). London: E&FN Spon Press. Young, S. (1976). Social and psychological effects of living in high-rise buildings. Ian Buchan Fell Research Project on Housing. Sydney: University of Sydney. Yuen, B., Yeh, A., Appold, S. J., Earl, G., Ting, J., & Kwee, L. K. (2006). High-rise living in Singapore public housing. Urban Studies, 43(3), 583–600. Yusoff, N., Driscoll, G. C., & Beedle, L. S. (1986). Tall buildings of the world. Bethlehem, PA: Council on Tall Buildings and Urban Habitat.

Chapter 2

Tall Building Living in High Density Cities: A Comparison of Hong Kong and Singapore Anthony G.O. Yeh and Belinda Yuen

2.1 Introduction This Chapter seeks to examine the high-rise living experience of two high-density cities: Hong Kong and Singapore. The aim is to investigate the difference in residents’ perception of tall building and tall building living between Hong Kong and Singapore to arrive at an understanding of: is there a relationship between how tall a person thinks a tall building is and his/her preference for life in high-rise buildings? The answer is pertinent to the debates on future urban density. Various urban scholars including Jacobs (1961) have long argued for proper density for urban dwellers. Ill-health, anxiety, isolation, for example, are some negative attributes of improper density ratios, commonly associated with high-rise living (Conway & Adams, 1977; Jephcott & Robinson, 1971). However, as explained in Chapter 1, tall buildings can help to mitigate some of the negative effects of high density. High rise housing development has been used by Hong Kong and increasingly in Singapore to meet their housing needs and make their high density environment more liveable. Hong Kong and Singapore have the highest densities and largest amount of tall housing in the world. The height of their residential buildings has risen from the post-war 4-storey walkups to the present 40–70 storey buildings. Hong Kong and Singapore are probably the extreme cases of tall residential building environment and high urban density in the world. To set the discussion context, it is relevant to define a number of terms. Urban density is the number of people living in an area, often measured by persons per square area. Building density is the percentage of land occupied by buildings. Crowdiness which is the main problem of high-density living is more related to building density and liveable space. With a fixed density, the decrease in building density may be achieved by making the buildings taller to increase the extended shared space and reduce crowdiness of the environment with the same amount of living space per flat (see Fig. 1.1). In other A.G.O. Yeh (B) Centre of Urban Studies and Urban Planning, The University of Hong Kong, Pokfulam, Hong Kong e-mail: [email protected]

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words, if there is a need to increase density, some of the negative effects of the increased density (e.g. feeling of crowding and withdrawal which are manifestations of the desire for more personal space) can be reduced by building taller buildings.

2.2 Tall Buildings and High Density Theoretically, tall buildings and high density may not be directly related. The increase in the number of storeys in a building may not necessarily lead to a big increase in density if the floor area per dwelling unit increases proportionally with the increase in the number of storeys. However, most cities increase the number of storeys without increase in dwelling area because of high land price and the need to increase urban density because of limited land. In some extreme cases, such as Hong Kong, there is also a decrease in dwelling area in order to make housing more affordable because of high land price. This leads to a big increase in the density. Many studies on high-density living have been done in the 1960s following major advancement in construction technology, building services, and fire fighting technology in that period of time which allowed buildings to be built much taller than before. There were concerns whether high density living as a result of the increase in the construction of high buildings will lead to an unacceptable urban environment and social pathology. The relationship between density and social pathology has been mainly confirmed by experiments on animals in laboratory settings (Mercer, 1975). Human beings are more adaptable than animals and the relationship between human density and social pathology has however not been well established in non-experimental settings. Many studies have shown that although high density is undesirable, there is little relationship between density and social pathology when other socio-economic variables are considered (Sundstrom, 1978). The perception of the environment, as well as the experience of crowdiness can be mediated by socio-economic status, cultural tradition, and the nature of activities performed in a given area (Stokols, Rall, Pinner, & Schopler, 1973). High density, though perceived as unpleasant, does not appear to have definite and consistent detrimental effects (Fischer, Baldassare, & Ofshe, 1975). Several researchers have disagreed that high urban density is associated with individual problems in health, social adaptation and pathological behavior (Baldassare, 1979; Patterson, Carson, & Hadden, 1996). There are many factors affecting social pathology in which density is just one of them. Other factors such as socio-economic background, education background, and health situation of individuals are more important variables than density in explaining social pathology (Millar, 1976; Sundstorm, 1978). It is found that the relationship between density and social pathology is mainly through the intervening variable of crowding. Crowding is a psychological subjective response to density. Social pathology is a result of stress and social conflict caused by crowding. As crowdiness is a psychological subjective response, high density does not always lead to stress (Freedman, 1975; Mitchell, 1972; Sundstrom, 1978). The effects of high density on crowdiness may be mitigated by personal

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background and interpersonal relationship. The perception of crowdiness depends on the duration of exposure to high density, expectation of the duration of the exposure, social interaction, the possibility of escaping to an external environment and the adaptation ability and tolerance of the persons concerned. The adaptation and tolerance of crowding depends on the socio-economic background, culture, age, education, and previous living environment of the individual. For a fixed density, people who are used to live in a denser environment will feel less crowded than someone who is used to live in a more spacious environment. Different cultures also have different levels of adaptation and tolerance to crowdiness. Asians and Chinese were often found to have a high adaptation and tolerance to crowdiness (Anderson, 1972; Schmidt, Goldman, & Feimer, 1976), although tolerance to crowdiness was often involuntary, due to social and economic disadvantage, and having no choice (Loo & Ong, 1984). There are two main types of density and their effect on crowding is different. They are personal space density and external space density which are related to Stokols’ (1972) and Baldassare’s (1979) concept of primary and secondary environment respectively. Personal space density is the measurement of density of the primary immediate working and living environment where the individual has more intimate contact with space for a relatively long time. It can be measured by the number of people per living/working space. External space density can be measured by the number of people in a certain area. The area can be measured by street blocks, neighbourhood, district, and the whole city. It is an expression of the secondary environment where space, facilities, and services are shared among the people within certain area. Because of the ease of measurement, it is one of the most commonly used indicators for density. In a two-dimensional city, there is little difference between residential density (persons/site area) and household density (persons/house or flat). However, in a three-dimensional city with high rise buildings like Hong Kong where there can be hundreds of flats on a single site, residential density can be many times higher than household density and therefore residential density is not a good indicator of household density. In fact, in most cases, it has grossly overestimated household density. Crowded primary environments are more undesirable than crowded secondary environment (Stokols, 1972). The effect of density on crowding is mainly through personal space density rather than external space density. Crowdiness may not be felt if external space density is increased but not personal space density such as the adding of more flats to a building site without reducing the size of each flat. The effect of density can be affected by the design, layout, open space, degree of sharing, traffic, and community facilities of the external and personal space. For external space, with a fixed density, people will feel less crowded if there are more open space, freer flow of traffic, and more community facilities. For personal space, with a fixed density, people will feel less crowded if there is a less degree of sharing and more privacy. The design and layout of rooms can make a room look more spacious. The subdivision and sound proofing of rooms can increase the privacy and reduce crowding. A small room can be made to appear larger by surrounding it with mirrored walls. A cluttered area will appear more crowded than one in which

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physical objects are neatly arranged. In other words, a reduction of the effect of high density can be achieved through better planning and management of the urban space. Hong Kong has the highest density in the world and therefore is a natural setting for carrying out research on high density development. Although Hong Kong has a much higher density than most Western cities where the relationship between high density and social pathology is studied most, similar to the findings of Western which have lower density, there is little evidence to find high density to be associated with social pathology. Mitchell (1972) found that emotional stress was not related to density. Stress was probably more influenced by inadequate income than density. He also found that forced social interaction between non-relatives as a result of flatsharing tended to create stress and tensions. It was the degree of sharing that caused stress rather than density. Easy escape from each other by retreating outdoor could significantly assist in reducing such stress. He suggested that there should be more attractive and spacious external environment in high-density areas as a means of reducing pressure from overcrowding indoor with high degree of sharing. Millar (1979) found that relationship between physical density and psychological problems was rather weak once socio-economic background had been taken into consideration. Many studies also showed that a substantial proportion of Hong Kong’s urban population did not see high density as a problem (Millar, 1976; Richardson, 1977). On the contrary, many of them enjoyed being surrounded by a large number of people (Millar, 1976; Traver, 1976). Chinese traditions and the previous poor living conditions when they were refugees were some of the probable reasons to explain the tolerance of the Hong Kong people towards high densities and overcrowding (Schmitt, 1963). Most of the above studies on high density living were done in Hong Kong when the density was the highest and there was a lack of urban planning and management. Even when the urban density and environment were at their worst in Hong Kong, there is no apparent evidence to support that high density is causing social pathology. The living environment has greatly improved since mid-1970s through better urban planning and management. Although improvements still remain, the negative effects of high density have been much mitigated with progressive improvement in design. With the progression, building height has increased. Studies in the 1970s on high density and tall buildings were done at the time when the buildings were mainly 20 storeys high which would be considered pretty low against present developments in Hong Kong and Singapore. Most of these studies were concentrated on density rather than the living environment of tall buildings, especially the effect of building height on residential satisfaction. Very few studies have addressed this. It was found that for low-rise housing, people may prefer to live in higher floors. In a study of low-rise 5-storey student dormitories in Ankara, Turkey, the finding was that students on the highest floor perceived their rooms as larger, less crowded and were more satisfied with their rooms than residents of the lowest floor (Kaya & Erkip, 2001). This is because rooms in the upper floors were brighter and less noisy. But, the preference for living in high-rise buildings is different. In the study of height preference for high-rise building in United Kingdom, Conway and Adams (1977) found that if respondents were given a free choice of floor in a 24-storey block, over 30% of them would have

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chosen the ground to second floors, another 15% the third to fifth floors, and only over 20% the twenty-first to twenty-third floors. This is mainly because the overall environmental setting is low rise housing. Prior experience and cultural background are factors influencing how residents perceive high-rise housing. Williamson (1981) did an excellent study by examining how Germans living in high rises (6–28 storeys) in and around Cologne and Dusseldorf adjusted to their high-rise living environment. Using structured and open-ended questions in an interview format, the study addressed how independent variables such as age, sex, martial status, and social class affected resident’s responses to the physical design, social networks, and adjustment of children in the high rise. Single people were aware of views offered from the windows of the high rise as well as the anonymity they experienced, whereas married people were conscious of balconies and their neighbours’ backgrounds, and chose to live on the lower floors. Older respondents complained more about management, children, the cleanliness of neighbours, and other aspects. It was also found that men were more negative than women; however, women were more concerned with specific problems such as security. Compared to men, women were more conscious of the poor design of entryways, hallways, and stairs. Herlyn (1970) suggested that, generally, height has a relatively positive factor. Findings showed that only 5% of residents wished to be on a lower floor than they were, whereas a third would like to have been on a higher floor. Greenberg and Greenberg (1977) suggested that satisfaction is strongly related to the floor on which one lives, density within the apartment, and anticipated duration of residence. Set against the high-rise development of Hong Kong and Singapore, most of these studies were done in relatively low-rise housing. In order to find out more about super tall building living, a study was carried out in Hong Kong and Singapore[1] respectively, trying to examine the influence of floor height on the perception of the living environment of tall buildings and whether there is a difference in the perception of tall buildings between Hong Kong and Singapore.

2.3 Super Tall Living in Hong Kong and Singapore 2.3.1 Methodology To compare the tall building living experience between Hong Kong and Singapore, a study was carried out in Singapore first through a questionnaire survey. The study in Singapore was reported in detail in Yuen, Yeh, Appold, Earl, Ting, and Kwee (2006). A similar questionnaire was used in Hong Kong for comparative purpose. In Singapore, the living experience of a sample of 218 residents in the 30-storey block precinct of Toa Payoh new town was collected. The high-rise blocks ranged from 12 to 30 storeys. In Hong Kong, a sample of 961 residents was collected from the Wang Tau Ho/Wong Tai Sin urban district (426 samples) and the Fanling/Sheung Shui new town (535 samples). The height of the sampled residential buildings ranged from 34 to 44 storeys which represented some of the tallest buildings in

14

A.G.O. Yeh and B. Yuen Table 2.1 Distribution of current floor levels of respondents Hong Kong

Singapore

Current floor level Number of respondents Percentage Number of respondents Percentage 1–5 floor 6–10 floor 11–15 floor 16–20 floor 21–25 floor 26–30 floor 31–35 floor 36–40 floor 41 floor or above

111 136 129 85 164 118 124 55 39

11.6 14.2 13.4 8.8 17.1 12.3 12.9 5.7 4.1

29 60 46 27 32 24

13.3 27.5 21.1 12.4 14.7 11.0 0.0 0.0 0.0

Total

961

100.0

218

100.0

the districts. Care was taken to include residents living on various floors from the lowest through to the top floor of the building. The distribution of the samples in Hong Kong and Singapore is shown in Table 2.1.

2.3.2 Main Findings The study in Singapore shows that perceptually, the residents are satisfied with their high rise living environment (Yuen et al., 2006). Similar satisfaction levels are found in Hong Kong. The studies show that high-rise living is a generally acceptable way of living in Hong Kong and Singapore and the residents are satisfied with the living environment. As found by Bonnes, Bonaiuto, and Ercolani (1991), the perception of crowdiness is a subjective reaction that is much related to the contextual spatiophysical features of the place that is being considered. Implicit in this type of inquiry is the notion that the height of nearby surrounding buildings has an impact on people’s attitude and subjective interpretation of that environment. Since the contextual environment of super tall buildings in Hong Kong and Singapore differs somewhat, with the former higher than the latter, there may be differences in the perception of tall buildings in Hong Kong and Singapore. Thus, the main focus of this Chapter is to examine the difference in the perception of tall building and tall building living between Hong Kong and Singapore. In other words, is there a relationship between how tall a person thinks a tall building is and his/her preference for life in high-rise buildings?

2.3.2.1 (A) Satisfaction of Living Height As shown by Table 2.2, sampled residents in the lower floors in Hong Kong and Singapore are less satisfied with the floor that they are staying as compared with

Total

Not high enough

Too low

Just right

Don’t care/never thought about it

Total

4.1

5.5

0.0 1.7 0.0 14.8 15.6 8.3 – – –

16.7

13.0 31.6 33.9 10.7 15.2 8.8 6.6 5.6 7.9 17.9

17.2 25.0 19.6 14.8 9.4 12.5 – – – 12.8

62.0 21.8 10.2 1.2 0.6 1.8 3.3 3.7 2.6 11.5

44.8 15.0 0.0 7.4 3.1 0.0 – – – 58.1

15.7 34.6 52.0 82.1 74.7 72.6 72.7 64.8 60.5 59.6

24.1 55.0 73.9 59.3 65.6 79.2 – – –

8.3

9.3 12.0 3.9 3.6 8.2 7.1 8.3 16.7 12.1

5.5

13.8 3.3 6.5 3.7 6.3 0.0 – – –

100.0

100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0

100.0

100.0 100.0 100.0 100.0 100.0 100.0

Hong Singapore Hong Singapore Hong Singapore Hong Singapore Hong Singapore Hong Singapore Kong (%) (%) Kong (%) (%) Kong (%) (%) Kong (%) (%) Kong (%) (%) Kong (%) (%)

1–5 floor – 6–10 floor – 11–15 floor – 16–20 floor 2.4 21–25 floor 1.3 26–30 floor 9.7 31–35 floor 9.1 36–40 floor 9.3 41 floor or above 18.4

Present floor level

Too high

Table 2.2 Comparison of satisfaction of living height

2 Tall Building Living in High Density Cities 15

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A.G.O. Yeh and B. Yuen

those in the upper floors. Only 15.7% in Hong Kong and 24.1% in Singapore living on 1st–5th floor considered the floor level that they were living was just right. On closer examination, a higher percentage of those living in 1st–5th floor in Hong Kong (62%) reported that they were living too low in Hong Kong as compared with Singapore (44.8%). In both Hong Kong and Singapore, residents staying in floors above 16th floor registered a higher satisfaction level with living height than those in lower floors. The satisfaction level is over 60% in both places. Because of the difference in the contextual environment of tall buildings, the satisfaction level of those living above 16th floor in Hong Kong is higher than those in Singapore. For most of the residents living in the tall buildings in Hong Kong, only a small percentage of less than 15% considered the floor that they are living to be too high. Even for those living on 41st floor or above in Hong Kong, only 18.4% considered that it is too high. By contrast, living on 5th floor is generally considered to be too high in most Western cities designed with suburban-style housing. But, in Hong Kong and Singapore, our data indicates that such living is considered to be too low. Similar findings were interestingly returned in a parallel study on high-rise living in Brisbane, Australia, where 30% of sampled respondents on 1st–5th floor considered their present floor level to be just right while 83% of those living on 16th–20th floor (the highest blocks surveyed) opined that their floor levels were just right. No one had rated their current floor level to be too high (Yuen, Appold, Yeh, Earl, Ting, & Kwee, 2003). These results prompted further investigation of the relationship between people’s perception of building tallness and their preference to live in high-rise housing. 2.3.2.2 (B) Perception of Tall Building Because of the contextual difference, the perception of a tall building is also apparently different between Hong Kong and Singapore. The perception of what is a tall and super tall building is consistently higher in Hong Kong than Singapore. In Singapore, 11% of the respondents considered a 20-storey residential building as a very tall building, but only 0.1% of those in Hong Kong considered this to be a very tall building (Table 2.3). A third of respondents (30.5%) in Singapore rated residential building of 40 storeys as a very tall building, but the proportion was only 17.7% in Hong Kong. Some 40% of respondents in Singapore had considered the 50-storey building to be a very tall building, whereas only 35% of respondents in Hong Kong rated such building as being very tall. Although there is a difference in the perception of tall and very tall buildings between Hong Kong and Singapore, there is not much of a difference in the perception of what is not a tall building. The perceived average height for both cities is around 17 storeys high which is considered to be tall by most low-rise western city standard. The implication is that the contextual environment may have influenced the perception of building tallness in these two high density cities, and because of the tall building environment, the perception of low rise building is similar. Even so, it is found that there is not much difference in the perception of tall buildings amongst the residents on different floor levels. In Hong Kong, regardless

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Table 2.3 Comparison of perceived building height

Building height 10-storey 15-storey 20-storey 25-storey 30-storey 40-storey 50-storey 60-storey Total Average height

Not a tall building

Tall building

Hong Kong (%)

Hong Kong (%)

Singapore (%)

31.4 27.4 20.2 13.6 5.1 1.5 0.6 0.3

32.1 30.2 17.0 11.9 7.4 1.2 0.1 –

100.0

100.0

17.3

16.9

1.03 4.99 13.23 20.09 28.01 21.04 7.77 – 100 31.5

Very tall building Singapore (%)

Hong Kong (%)

Singapore (%)

1.3 3.8 21.5 26.4 22.1 15.9 8.9 0.0

– – 0.1 0.9 4.0 17.7 35.3 42.1

0.2 0.2 11.3 3.6 14.7 30.5 40.0 –

100.0

100.0

100.0

24.7

51.4

39.6

Fig. 2.1 Perception of tall building by present floor level

of the floor level of respondents, the perceptions of what is not a tall building, tall building and super tall building are very similar (Fig. 2.1). This seems to indicate that the floor level does not have much influence over one’s perception of tall building. The contextual environment appears much more important than which floor level one is living, in the perception of what height makes a building tall. 2.3.2.3 (C) Highest Preferred Living Height The average highest preferred floor level is higher in Hong Kong than Singapore (Table 2.4). It is 29.3 for Hong Kong and 20.9 for Singapore. Only 15.3% of the

18

A.G.O. Yeh and B. Yuen Table 2.4 Comparison of highest preferred floor level Hong Kong Highest preferred floor

No.

1–5 floor 6–10 floor 11–15 floor 16–20 floor 21–25 floor 26–30 floor 31–35 floor 36–40 floor 41–45 floor 46–50 floor 51 floor or above

2 24 17 168 82 244 77 139 10

Total

857

Average floor level

Singapore %

%

0.2 2.8 2.0 19.6 9.6 28.5 9.0 16.2 1.2 11.0

2 23 33 40 26 58 28

5

2.3

100.0

215

100.0

94 29.3

No.

1.0 10.7 15.3 18.6 12.1 27.0 13.0

20.9

respondents in Singapore were willing to living above 31st floor, whereas this proportion has jumped to 37.4% for Hong Kong; 11% of those in Hong Kong were willing to live above 46th floor. The findings further lend support to the argument that contextual difference in the physical setting of Hong Kong and Singapore has influenced the higher preferred floor level. Hong Kong has more taller buildings than Singapore and its residents are consequentially emboldened by the familiar living experience and more willing to live higher in Hong Kong than Singapore. Contrary to the lack of relationship between floor level and the perception of what height makes a building tall, there is a difference in the highest preferred floor level and respondent’s present floor level (Fig. 2.2). In Hong Kong, the percentage of those who are willing to live higher than 40 storeys appears on an upward trajectory with floor height, rising from around 50% among those living below 20th floor to over 78% for those who are living above 40th floor. Lower floor residents appear to show less preference to live on higher levels than residents on higher floors. In other words, residents on higher floors appear more willing to live higher as they are familiar with the height. The willingness to live in 50-storey building is expectedly higher among those who are already living above 40th floor. 2.3.2.4 (D) Concerns of High-Rise Living It seems that there is not much of a difference in the concerns about high-rise living in Hong Kong and Singapore (Table 2.5). The first six concerns are the same between Hong Kong and Singapore. They are fire risk, life breakdown, neighbours, crime in lift, accidental falling off the building, and lack of neighbourhood facilities. They constitute 76.7 and 88.0% of the concerns of the respondents in Hong Kong and Singapore respectively. Perhaps because of the difference in housing design, their order of importance is slightly different. Hong Kong’s respondents ranked

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Fig. 2.2 Willingness to live in higher floor of tall building by present floor level Table 2.5 Comparison of concerns about high-rise living Hong Kong Concerns about high-rise living Fire risk Lift breakdown Who you have as your neighbors Crime in the lift Accidental falling off of family members Lack of neighbourhood facilities Power failure Traveling time in lift Collapse of the building Walking along the common corridor to reach your flat Other worries Height of the building Total

Percentage

Singapore Rank

Percentage

Rank

25.8 13.3 11.9 9.0 8.8

1 2 3 4 5

9.0 20.0 14.0 14.0 5.0

5 2 3 4 6

7.9 6.9 6.3 3.0 2.7

6 7 8 9 10

26.0 2.5 2.5 2.5 2.0

1 7 8 9 10

2.4 2.1

11 12

1.5 1.0

11 12

100.0

100.0

fire risk as their number one concern, whereas it was ranked 5th for respondents in Singapore. Lack of neighbourhood facilities ranked 1st in Singapore but ranked only 6th in Hong Kong. The ranking of other minor concerns, such as power failure, travelling time in lift, collapse of building, and walking along the common corridor to reach your flat are the same in Hong Kong and Singapore. The height of building

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A.G.O. Yeh and B. Yuen

is of very low concern in Hong Kong and Singapore. This is perhaps a reflection of respondents’ perception of building tallness and general satisfaction and familiarity with the tall environment.

2.4 Conclusion Although Hong Kong and Singapore may have the highest density as well as the tallest residential building environment in the world, the residents living in its tall buildings are in general quite satisfied with their living environment. In Western cities, floor higher than the 5th floor is normally considered to be very high. But in Hong Kong and Singapore, they are considered to be too low. Lower floor respondents prefer to live on higher floors. The average highest preferred floor level is about 29.3 for Hong Kong and 20.9 for Singapore. As we reported in Yuen et al. (2006), the pull factors of high-rise living include better view, less noisy, and better air quality. The preference for living in higher floors as illustrated by the Hong Kong situation is a reflection of flat price with height. The house price and rentals for higher floors are much higher than lower floors, especially for those with unobstructed sea views. There is therefore a strong desire to live as high as possible for those in affordability position as there is an implicit social status. In addition, there is a reinforcement effect that those who are familiar with life in high-rise are more prepared to experiment with higher floor living while those who have little notion of the building height are less inclined towards moving higher. The comparative study of Hong Kong and Singapore shows that the perception of tall building and super tall building and the highest floor that one is willing to live in varies from place to place and time to time, depending on the contextual environment. A “tall” building in city A may be a very low building in city B, but it may become a “super tall” building in another city C. The perception of tall building will also change through time. A “tall” building at one point of time may become a “low” building some years later when the building environment is dominated by other taller buildings. People become adjusted to the general building environment with familiarity. Although Hong Kong and Singapore both have a high building environment, because of the difference in the contextual environment, the perception of tall buildings in the two cities are not the same. Because the residential buildings of Hong Kong is on average higher and lie closer to each other than in Singapore, Hong Kong’s residents seem to be more used to living in super tall buildings. The perception of the height of super tall building is higher than that in Singapore. The study shows that when people are used to living in tall buildings, they are apparently quite satisfied with it. There is seemingly not much difference in their perception of building tallness whether they are living in lower floors or upper floors in super tall buildings. Needless to say, the adjustment is a gradual adjustment through time through the evolution of the built environment. If the study in Hong Kong was done 10 years ago when the contextual building height environment was very similar to the present environment in Singapore, the perception of the height of a tall building and

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the highest floor that one is willing to live could well be lower than what is obtained now. Many of the “not so tall” 30-storey building would be considered as “very tall building” in Hong Kong in the 1950s when most of the buildings were only 5–8 storeys high. If this is indeed true, might we see a convergence of perceptual height with optimal height over time? The implication is that many of the concerns of those living in super tall buildings could be addressed in the architecture, design and management of these buildings (Ali & Armstrong, 1995; Fong, 1985; Yeh, 2000). For example, the installation of devices to break and minimize the impact of fallen objects from height. Higher setback of windows can also help the residents not to see the full view of the distant ground below them so that they can focus by focusing their view on the wider horizon which is less frightening. The installation of CCTV in the lift can help to minimize concern over crime in lift. Good maintenance can minimize lift breakdown. In other words, better architecture, design and management can help make super tall buildings more liveable and mitigate the concerns of high-rise living. In both Hong Kong and Singapore, as tall buildings and even super tall buildings become common in the city, the building of high-rise is paralleled by careful block and flat design, and the provision of greenery and open spaces between buildings to relieve the crowdiness. Despite attention given to compact city development, we are not advocating for the massive building of super tall buildings. Although from the economic point of view, as shown in the study by Chau, Wong, Yau, and Cheung (2007), the optimal height for Hong Kong is 60 storeys with sea view and 57 storeys without sea view, there are many considerations in deciding how tall a building should be built in a particular city. It does not depend on economics alone. It also depends on the needs, culture, and social acceptability. The indication from our data is that the average highest preferred floor level at the present time is about 29.3 for Hong Kong and 20.9 for Singapore. Awareness of and research into people’s perception of building tallness and willingness to live in high-rise can help to inform and enrich efforts to recast the density question and sustainable urban development including the current revisit of high-rise in urban development agenda. The comparative study of Hong Kong and Singapore shows that people apparently adjust to living in super tall buildings through time. It seems that when the contextual building height environment is gradually predominated by very tall buildings, people are willing to living in them and willing to live higher. Further study is needed to test the cultural and contextual dimension on the perception of tall buildings. More study is needed to understand the psychological dimension of highrise living. People may not be accustomed to tall building living if there is only one tall building in the city. If the findings in the extreme cases of Hong Kong and Singapore have any indication, the change in the contextual environment, the appearance of more tall buildings may help increase the receptivity of tall building living. However, the change in contextual environment is but one aspect of the perceived environment. It is unlikely to bear impact if the tall building compact environment is not carefully planned, designed and managed to minimise crowdiness and maximise sustainability. For cities which need to increase their urban population

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density, the construction of “tall” housing which is relatively taller than their present ones can be one of the measures for mitigating the negative effects of crowdiness that are often associated with the increase in urban density.

Note 1. The major findings of the Singapore study has been reported in Yuen et al. (2006).

References Ali, M. M., & Armstrong, P. J. (Eds.). (1995). Architecture of tall buildings. New York: McGraw-Hill. Anderson, E. N. (1972). Some Chinese methods of dealing with crowding. Urban Anthropology, 1(2), 141–150. Baldassare, M. (1979). Residential crowding in urban United States. Berkeley, CA: University of California Press. Bonnes, M., Bonaiuto, M., & Erocolani, A. P. (1991). Crowding and residential satisfaction in the urban environment: A contextual approach. Environment and Behavior, 13(5), 531–552. Chau, K. W., Wong, S. K., Yau, Y., & Cheung, A. K. C. (2007). Determining optimal building height. Urban Studies, 44(3), 591–607. Conway, J., & Adams, B. (1977). The social effects of living off the ground. Habitat International, 2(5/6), 595–614. Fischer, C. S., Baldassare, M., & Ofshe, R. J. (1975). Crowding studies and urban life: A critical review. Journal of the American Institute of Planners, 41, 406–418. Fong, P. K. W. (1985). Management of high rise residential development in Hong Kong. Cities, 2, 243–251. Freedman, J. (1975). Crowding and behaviour. San Francisco: W.H. Freeman. Greenberg, J., & Greenberg, C. I. (1977). A survey of residential responses to high-rise living. In D. J. Conway (Ed.), Human response to tall buildings (pp 168–174). Stroudsburg, PA: Dowden, Hutchinson & Ross. Herlyn, U. (1970). Wohnen im Hochhaus. Stuttgart: Karl Kramer Verlag. Jacobs, J. (1961). The death and life of great American cities. London: Vintage Books. Jephcott, P., & Robinson, H. (1971). Homes in high flats: Some of the human problems involved in multi-storey housing. Edinburg: Oliver and Boyd. Kaya, N., & Erkip, F. (2001). Satisfaction in a dormitory building: the effects of floor heights on the perception of room size and crowding. Environment and Behavior, 33(1), 35–53. Loo, C., Ong, P. (1984). Crowding perceptions, attitudes, and consequences among the Chinese. Environment and Behavior, 16(1), 55–87. Mercer, C. (1975). Living in cities: Psychology and the urban environment. Harmondsworth: Penguin. Millar, S. E. (1976). Health and well-being in relation to high density living in Hong Kong. Unpublished PhD thesis, Australian National University, Canberra. Millar, S. E. (1979). The biosocial survey in Hong Kong. Canberra: Australian National University. Mitchell, R. E. (1972). Levels of emotional strain in Southeast Asian cities. Taipei: Orient Cultural Service. Patterson, C. C., Carson, D. J., & Hadden, D. R. (1996). Epidemiology of childhood IDDM in North Ireland 1989–1994: Low incidence in areas with highest population density and most household crowding, North Ireland diabetes study group. Diabetologia, 39, 1063–1069. Richarson, T. (1977). North point, Hong Kong: A case study of high density. Architectural Association and the Royal Institute of British Architects.

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Schmidt, D., Goldman, R., & Feimer, N. (1976). Physical and psychological factors associated with perceptions of crowding: an analysis of subcultural differences. Journal of Applied Psychology, 61(3), 279–289. Schmitt, R. G. (1963). Implications of density in Hong Kong. Journal of the American Institute of Planners, 29(3), 210–217. Stokols, D. (1972). A social-psychological model of human crowding phenomena. Journal of the American Institute of Planners, 38, 72–83. Stokols, D., Rall, M., Pinner, B., & Schopler, J. (1973). Physical, social, and personal determinants of the perception of crowding. Environment and Behavior, 5, 87–115. Sundstrom, E. (1978). Crowding as a sequential process: Review and research on the effects of population density on humans. In A. Baum & Y. M. Epstein (Eds.), Human response to crowding (pp. 31–116). Hillsdale, NJ: Lawrence Erlbaum Associates. Traver, H. (1976). Privacy and density: A survey of public attitudes towards privacy in Hong Kong. Hong Kong Law Journal, 6(3), 327–343. Williamson, R. C. (1981). Adjustment to the high-rise variables in a German sample. Environment and Behavior, 13(3), 289–310. Yeh, A. G. O. (2000). The planning and management of a better high density environment. In A. G. O. Yeh & M. K. Ng (Eds.), Planning for a better urban living environment in Asia (pp. 116–143). Aldershot: Ashgate. Yuen, B., Appold, S. J., Yeh, A., Earl, G., Ting, J., & Kwee, L. K. (2003). Living experience in super tall residential buildings. Final report (unpublished), National University of Singapore. Yuen, B., Yeh, A. G. O., Appold, S. J., Earl, G., Ting, J., & Kwee, L. K. (2006). High-rise living in Singapore public housing. Urban Studies, 43(3), 583–600.

Chapter 3

Physical Environment of Tall Residential Buildings: The Case of Hong Kong Stephen S.Y. Lau

3.1 Introduction Increasing urban populations, scarcity of urban land, depletion in resources and severe impact of urban development on sustainability are critical contemporary issues. Such issues have vast implications on the desirability of compact, highrise high-dense built forms. Yet, the environmental quality and social acceptance of these forms remain barely studied. This chapter reviews some of the critical environmental implications posed by the closely packed high-rise building and high urban densities. High-rise buildings of Hong Kong1 are explored to discuss the pressing challenges of poor air quality, ventilation, daylight, lack of open space and noise pollution. Both quantitative and qualitative appraisals of Hong Kong residents living in high-rise buildings are used to analyse the environmental challenges. Recommendations for improvements using current practices in Hong Kong and possible solutions for the future are also discussed.

3.2 Urban Morphology and Its Implications: The High Rise, High Density Compact Setting Urban morphology is the study of the physical form of a city. Broadly, such study would consider the street patterns, building sizes and shapes, architecture, population density and patterns of residential, commercial, industrial and other uses, among other things. Special attention is given to how the physical form of a city changes over time and how different cities can be compared with each other. Related

S.S.Y. Lau (B) Department of Architecture, The University of Hong Kong, Pokfulam, Hong Kong e-mail: [email protected]; [email protected] 1 Hong Kong is used as an example for the study because its choice of an urban form is seen to create a major influence on numerous Chinese cities.

B. Yuen, A.G.O. Yeh (eds.), High-Rise Living in Asian Cities, C Springer Science+Business Media B.V. 2011 DOI 10.1007/978-90-481-9738-5_3, 

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to the physical form, urban morphology would also study social forms, which are expressed in the physical layout of a city, and conversely, how physical form produces or reproduces various social forms. Urban morphology is at times considered as the study of urban fabric, as a means of discerning the underlying structure of the built landscape. This approach challenges the common perception of unplanned environments as chaotic or vaguely organic through an understanding of the structures and processes embedded in urbanization. It is widely accepted that there is a close relationship between shape, size, density and uses of a city and the sustainability of that city. However, this chapter is limited to the characteristics of a high-rise, high-density compact urban environment: Hong Kong and its environmental implications. It is said that urban intensification creates frequent walking trips and better accessibility to facilities (Masnavi, 2000). In a compact city the reduction in car ownership, vehicular trips and increase of pedestrian and transit use alleviate the environmental consequences associated with the automobile. Compact city has many advantages such as conservation of countryside, reduced need to travel by car and thereby reduction in fuel and pollution, support for public transport, walking and cycling, better access to services, more efficient utility and infrastructure provisions, and revitalization and regeneration of urban areas (Burton, 2000). In contrast to compact city, dispersed cities suffer from inefficient transport management and long commuting trips, which lead to a high dependency on automobile high energy consumption and pollution (Newman & Kenworthy, 1992). Although high density combined with mixed use allows for high accessibility to a majority of users, the mixing and co-location of incompatible uses such as housing, community, recreational and public spaces near commercial, industrial and transport can have consequences on the physical quality of the living environment. Greater intensification has implications on urban green space. Even though a valuable contributor to urban quality, urban greenery provision is often reduced under pressure from other land use development. Research claims that compact city suffers from a perceived lack of greenery, open spaces and parks which provision is seen to be better in low-density environment (Masnavi, 2000). However, urban sprawl results in unsustainable levels of resource use and inequitable lifestyles (Williams, Burton, & Jenks, 2000). In comparison with urban sprawl, the compact city is a dominant model for sustainability (Jenks, 2000). Yet, evidence on the impact of higher and lower densities on sustainability, the impact of centralized decentralized city form on sustainability are lacking. Review of some city forms indicates both advantages as well as disadvantages in sustainability. For example, forms that reduce travel and are fuel-efficient may be harmful to the environment and have social inequities. They may be locally beneficial but not city-wise beneficial (Williams et al., 2000). The effects of urban density on the total energy demand of a city are complex and at times conflicting (Givoni, 1998). Compactness of land use patterns will bring benefits to energy distribution and transport system design, but crowded conditions may create congestion and undesirable local microclimate (Hui, 2000). The compact city challenges are mainly associated with environmental quality and social acceptability (Williams et al., 2000).

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3.3 A Compact City: Case of Hong Kong A multiple intensive land use development in Hong Kong is formed by an intensification of land use through mixing residential and other uses at higher densities at selected urban locations, together with an efficient transport and pedestrian network (Lau & Coorey, 2007; Lau, Ghiridharan, & Ganesan, 2003). Hong Kong is one of the Asian cities that have evolved as a compact urban form. Situated at the south-eastern tip of China, Hong Kong is ideally positioned at the centre of rapidly developing East Asia. With a total area of 1,103 km2 , it covers Hong Kong Island (80.41 km2 ), the Kowloon peninsula just opposite (46.93 km2 ), and the more rural section of Hong Kong New Territories and 262 outlying islands (976.38 km2 ). The central part of both Hong Kong Island and Kowloon are hilly rising to a height of 3,050 m. Only 21.8% of Hong Kong land is built up, concentrating on the triangular tip of Kowloon and the coastal strip of northern Hong Kong Island. The total population in Hong Kong is 6,864,346 with the median age rising from 30 in 1988 to 36 in 2006 (Census and Statistics Department, 2006). The median monthly household income is HK$15,000. A population growth rate of approximately 1 million is observed in every 10 years in the last decade and the population forecast for 2,030 is 9 million (Fung, 2001). Although the total population density is 6,380 persons per km2 , urban areas hold a staggering population density of over 55,000 persons per km2 where certain districts rank among the most densely populated places in the world. The density of public housing reaches at least 2,500 residents per ha, which is twice the density of the most crowded residential areas in mainland China (Xue, Manuel, & Chung, 2001). High-density in a land limited country like Hong Kong is the norm. Cities often respond to development pressure by setting targets for increased urban densities, and the establishment of high-rise cityscape and compact urban settings is unavoidable (Hui, 2000). A chronological classification of tall building types in Hong Kong can be observed. The typology includes the verandah type from the 1920s, the cantilevered living quarters type from the 1950–1960s, the rectangular mass type from the 1970s, and the podium type from the 1980s onwards. Among the rectangular mass type and podium type buildings, several shapes of building forms are observed such as the rectangular, “Y” shape, clusters and crucifix shapes. When observing the pattern of development at a district scale, two significant variations in development is observed, namely, the clusters of multiple intensive land use developments around the mass transit nodes and the linear multiple intensive land use development alongside main roads and streets in the older parts of Hong Kong. The cluster of a high-density Multiple Intensive Land Use (MILU)2 development is mainly observed along (under) the three main rail lines of mass transit railway, namely, the Airport Railway, Urban Lines and Tseung Kwan O Lines. They are three-dimensional distribution of density and land uses integrated by three parallel

2 MILU is mixed use (multi functional) and high-density (intensive) development. The concept of MILU was formulated to tackle the problems of urban sprawl and the development of dysfunctions of urban, suburban and rural areas (Haccou, 2007).

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Primary MILU

Secondary MILU

Tertiary

MILU Fig. 3.1 Multiple intensive land use cluster development. Sources: Lau and Coorey (2007), and Wikipedia (2008)

commuting levels, namely, the mass transit rail (MTR), Kowloon-Canton railway, subways below ground, buses, taxis, light rail transit and tramways on ground and walkways above ground which are then vertically connected via ramps, stairways, elevators and escalators. Such developments are built above or connected in close proximity to mass transit railway and other public transport modes. As seen in Fig. 3.1, when several MILU nodes are developed in close proximity, an interdependency is formed among these developments where land use functions and services are shared, thus creating primary, secondary and tertiary interdependent zones (Lau et al., 2003). Plot ratios, also known as Floor Area Ratios, of up to 15 for commercial uses and up to 10 for residential uses have led to buildings of up to 80 storeys built above 3–4 level podiums. The podium levels incorporate the secondary supporting functions such as commercial, recreational, government, institutional and community (GIC) land uses while the primary residential, office or hotels/serviced apartments are located above as seen in Fig. 3.2. Four major types of MILU developments can be discerned according to its mix of land use types: 1. The primary use being office and/or hotel/serviced apartments with supporting secondary commercial, GIC and transport uses; 2. Primary use being residential supported by secondary commercial, GIC and transport uses; 3. Primary use being both residential and office supported by secondary commercial, GIC and transport uses; 4. Primary uses being office, residential, hotel/serviced apartments and secondary commercial, GIC and transport uses.

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Residents

Recreation,open space shops

Carpark,bus,taxi

GIC MTR

Meifoo Sun Chuen

Sunshine City Tung Chung Residential Land Use

Car Parks

Commercial Land Use

Transport (MTR/Taxi/Bus)

GIC(Government Institutional & Community Land Uses) Re Recreational land Uses (Open Spaces / Play Areas)

Connectivity of Land Uses

Fig. 3.2 Multiple intensive land use cluster development. Source: Lau and Coorey (2007)

These development clusters are defined as primary MILU nodes (Lau et al., 2003). Table 3.1 illustrates some examples of the four types of primary MILU developments that are commonly seen in Hong Kong. In Hong Kong where the buildable land resources are scarce due to hilly terrain and scarcity of usable land, tall buildings serve as an optimal option to maximise development potentials and best returns. Reduction in travel time due to intensification of mixed land uses contributes to efficiency and economic viability of the city (Wu, 2005). The concept of home-work-play gives the residents efficiency, convenience and savings in time. Tall buildings also provide a heuristic device to meet the housing demands for the increasing population. Additionally, the mixed use

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Table 3.1 Four combinations of MILU developments in Hong Kong. Sources: Hong Kong Mass Transit Railway Corporation (2008), Wikipedia (2008), Google Earth (2008) Type A office related MILU

Type B residential related MILU

International Finance Centre (IFC), Hong Kong Primary useoffice/ hotel/serviced apartments Secondary useretail, transport

Kornhill kowloon

Total GFA - 415,900 Office GFA - 254,190 Retail GFA - 59,460 Hotel / service apartments - 102, 250

Residential flats - 6,648 (Ave flat size 54 – 115) Retail – 104,170 GIC – 9,640

Primary useresidential Secondary usecommercial, GIC, transport

Type C office and residential related MILU

Type D office, residential and hotel/serviced apartment related MILU

Telford development, Kowloon station Kowloon Bay, development – Union Square, Kowloon Kowloon Primary usePrimary useresidential, office, hotel and residential and office serviced apartments Secondary useSecondary use-retail, transport commercial, GIC, transport

Residential flats - 4,992 (Ave flat size 44 – 62) Retail - 83,201 Office - 26,635 GIC - 909

Total GFA - 1,090, 011 Residential GFA - 608,011 Office GFA – 231,778 Retail GFA - 82,750 Hotel/service apartment 167,472

2 office towers 32 residential blocks 41 residential blocks 16, residential towers retail in multi level shopping centre 2 shopping centers, 2 mixed use (hotel /serviced apartments /residential) open spaces, recreation cinema, supermarket, podium, open spaces, towers, deluxe hotel and deluxe and community open spaces 118, storey of office and serviced apartment facilities recreation, hotel transport interchange linked to train station community facilities, shopping centre with train, bus, mini and parking office tower open spaces, recreation and bus, taxis, hotel transport coaches, tour buses and interchange - train, bus, community facilities, transport interchange-train, parking mini bus, taxi and bus, coaches, mini bus, parking taxis, hotel shuttle and tour buses and parking

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nature of developments creates places that are active and lively for longer duration of time, providing safe neighbourhoods and additional time for use of urban spaces for its residents. Rich, vibrant urban spaces are created within neighbourhoods. Urban intensification and compactness also provides savings in infrastructure and services, and high penetration of infrastructure and services for all residents. For example, it results in an overall reduction in energy use and traffic fumes (Wu, 2005). High-rise building rather than urban sprawl reduces the use of woodlands and forest areas for development, saving valuable land resources for future use and recreation purposes. In Hong Kong such country parks and woodlands can be easily accessed. Yet, there are some consequences associated with tall residential built forms arising from the very high population and extreme density. Both social and environmental implications are prevalent in such conditions. This chapter is specifically focused on the environmental implications and various measures and solutions that may mitigate the environmental consequences of tall residential buildings taking Hong Kong as a case study.

3.4 Environmental Challenges Related to Compact High-Rise Built Form High-density living in Hong Kong is strongly linked with significant air, water and noise pollution. Drastic environmental implications such as living in busy urban centres with high air and noise pollution, poor lighting and ventilation in individual housing units, urban heat island and wind tunnel effects are observed in Hong Kong’s high-rise building developments. One of the problems related to mixed land use developments at very high intensities is the incompatibility of uses. This problem is particularly apparent in the old built-up areas because of a lack of comprehensive planning in the past (Fung, 2001). Examples include those residential developments that face environmental nuisance due to its location adjacent to industrial areas. Another example is where highways pass through residential areas, posing the threat of noise and air pollution. Probably due to poor ventilation and lighting conditions, as high as 50% of all electricity used in Hong Kong is for lighting and space conditioning (Wu, 2005). Air conditioning accounts for one-third of the total power consumption of Hong Kong each year and costs HK$10 billion (Ching, 2005). High space conditioning further aggravates the outdoor climate conditions creating a vicious cycle of environmental pollution such as urban heat island. Table 3.2 outlines the positive and negative effects of high density on city’s energy demand as identified by Hui (2000). Current air pollution levels in Hong Kong are high due to the high intensity of emissions from industry and traffic as well as a lack of proper environmental planning in the past. The number of motor vehicles is increasing due to population growth and demands. Many areas in Hong Kong are topographically confined by hills and the air pollution dispersion in these areas is inhibited (Hong Kong

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Table 3.2 Positive and negative effects of urban density on city’s energy demand. Source: Hui (2000) Positive effects

Negative effects

Transport – Promote public transport and reduce the need for, and length of, trips by private cars

Transport – Congestion in urban areas reduces fuel efficiency of vehicles

Infrastructure – Reduce street length needed to accommodate a given number of inhabitants – Shorten the length of infrastructure facilities such as water supply and sewage lines, reducing the energy needed for pumping

Vertical Transportation – High-rise buildings involve lifts, thus increasing the need for electricity for the vertical transportation

Thermal Performance – Multistory, multiunit buildings could reduce the overall area of the building’s envelope and heat loss from the buildings – Shading among buildings could reduce solar exposure of buildings during the summer period Energy Systems – District cooling and heating system, which is usually more energy efficiency, is more feasible as density is higher Ventilation – A desirable air flow pattern around buildings may be obtained by proper arrangement of high-rise building blocks

Ventilation – A concentration of high-rise and large buildings may impede the urban ventilation conditions Urban Heat Island – Heat released and trapped in urban areas may increase the need for air conditioning Natural Lighting – The potential for natural lighting is generally reduced in high-density areas, increasing the need for electric lighting and the load on air conditioning to remove the heat resulting from the electric lighting Use of Solar Energy – Roof and exposed areas for collection of solar energy are limited

Planning Department, 2006a). Hong Kong has been facing two air pollution issues: local street-level pollution caused by motor vehicles; and regional smog problem caused by motor vehicles, industry and power plants both in Hong Kong and in the Pearl River Delta. Street level pollution is mainly caused by the large number of motor vehicles in highly dense urban areas. The emissions are trapped in between the very tall buildings along the streets. The tall stacks of building towers create urban walls that are barriers to wind circulation and vistas in the city. Further, it causes wind tunnel effects and unsafe environments at street levels. Walking at street levels in compact cities is no longer safe for the pedestrian. The high flow of vehicular traffic damages the quality of the street environment, with their high noise and air pollutants. Therefore, whether within enclosed spaces or outside in the public areas and streets, the quality of the living environment is being damaged, affecting the overall quality of life. Furthermore, since 2006, there has been an increasing concern on the “wall effect” caused by uniform high-rise developments, which adversely impact air circulation. A survey carried out by the environmental group, Green Sense revealed that 104 of 155 housing estates surveyed have a “wall-like” design (Yueng, 2006).

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The survey found the estates of Tai Kok Tsui and Tseung Kwan O as the best examples of this kind of design. In May 2007, citing concern over developments in West Kowloon, and near Tai Wai Yuen Long railway stations, some legislators called for a law to stop developers from constructing tall buildings which adversely affect air flow in densely populated areas, but the bid failed (Wong, 2007). More recently, in December 2008, a protest against “wall-effect” for a dozen of current and planned constructions was held at Central Government Offices (Ng, 2008). These protesters were also concerned about the development plans for Nam Cheong and Yueng Long stations. Tall buildings also pose threats to public safety and health in terms of easy spread of disease and viruses, fire risks and domestic accidents. Adequate ventilation and building maintenance are therefore an important issue for high-rise buildings in order to avoid the spread of disease and accidents associated with dilapidated structures (Wu, 2005). Study on residents’ satisfactions and aspirations of high-rise living in Hong Kong shows that better view, less noise, better air quality are the major reasons for people to opt for high-rise living (Lau, 2002). The higher selling prices for apartments on higher floors are also attributed to better views, less noise and better environmental quality. This trend may seem to suggest that residents who choose living on higher floors are seeking an escape from the environmental problems since living on higher floors allows one to be further way from the city surface. But, opting for taller buildings alone may not be a solution to the problem.

3.4.1 Air Quality, Wind Environment and Air Ventilation There exists a strong pressure from people to improve air quality and environment. The government has acknowledged this requirement and taken measures to improve the environment. For example, it has implemented vehicle emission and fuel standards, cleaner alternatives to diesel, emission inspection and enforcements such as controlling smoky vehicles, etc. and promoting vehicle maintenance and ecodriving. In his 2006–2007 policy address, the Chief Executive of Hong Kong has emphasized the importance of addressing these issues in order to secure sustainable development for future generations. He has outlined some of the measures, To reduce air pollution, we have formulated the Pearl River Delta (PRD) Regional Air Quality Management Plan. This plan, prepared in partnership with the Guangdong Provincial Government, aims to achieve specific emissions reduction targets by 2010. We have now set up a 16-station air quality monitoring network in the PRD. Based on the data collected, the PRD Regional Air Quality Index is released everyday on the Internet to keep the public informed of the actual regional air quality. The data collected will also help us assess the effectiveness of our pollution reduction measures . . . In Hong Kong, we have imposed emission caps on power plants at Castle Peak, Black Point and Lamma Island. These emission caps will be progressively tightened to meet the 2010 emission reduction targets. (Chief Executive, 2006–2007).

In 2006, particulates and nitrogen oxides levels on the street have dropped by 13 and 19% respectively since 1999. The number of smoky vehicles on the road has also reduced by about 80% (Environmental Protection Department, 2006). Increased

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use of mass transport and reduction in private car and taxi could help to reduce the air pollution levels caused by vehicular traffic. In addition to policy measures, urban design measures are suggested for improving air ventilation (Chinese University of Hong Kong, 2005; Hong Kong Planning Department, 2006b). Recent study identifies the following urban design issues as a means to a better quality and comfortable urban environment: lack of breezeways air paths; tall and bulky buildings closely packed causing undesirable wind breaks to urban fabric; uniform building heights resulting in wind skimming over the top of buildings and not being re-routed into the fabric; tight narrow streets not aligned with prevailing wind with tall buildings resulting in urban canyons; lack of urban permeability-with few open spaces, minimal gaps between buildings, excessive podium structures reducing air volumes at ground levels; large building blocks forming wind barriers; projections from buildings and obstructions on narrow streets and general lack of soft landscaping, shading and greenery as contributing to poor air ventilation and environmental quality in high-rise, compact built areas (Chinese University of Hong Kong, 2005; Hong Kong Planning Department, 2006b). For better urban air ventilation breezeways in the forms of roads, open spaces, and low-rise building corridors are suggested to allow air penetration to inner parts of urbanized areas. Breezeways, roads, main streets and avenues should be aligned either parallel or 30◦ to the prevailing wind directions. Open spaces must be linked and aligned to form unobstructed wind corridors with low-rise structures alongside them. Space between buildings must be maximized, especially in large sites with dense developments. The longer frontages of blocks may be aligned parallel to wind corridors, and non-built areas and setbacks may be introduced to further allow for good wind penetration. To maximise the penetration of sea breezes and land breeze water front sites may take special precautions to avoid blockages in wind paths (Chinese University of Hong Kong, 2005). Street patterns, building heights, open spaces, density, and landscape will determine the air ventilation, solar radiation, day lighting and air temperature in compact high-rise built forms having implications on indoor and outdoor environmental quality. To illustrate, reference is made to the natural ventilation study conducted for a proposed luxury residential development in Shenzhen, China. An assessment of air flow, solar energy and daylighting is done using computer based simulation tools such as Airpak (USA), ECOTECT (UK) and RADIANCE (USA) (Lau & Li, 2006). Table 3.3 shows the airflow study and wind velocities within the compact high dense residential site. All three graphs in Table 3.3 show high age of air, indicating low ventilation and increased stagnated air. In the surrounding areas of the high-rise towers the age of air reduces when elevation height increases from 5 to 40 m, indicating better ventilation and cleaner air in the upper floors. The low age of air is also spread in larger proportions when the elevation height increases. As seen in the graphs, both low- and high-rise buildings form a wall that is oriented perpendicular to the prevailing wind patterns. This creates a barrier to the southeast winds and creates stagnant air in the leeward sides of the buildings. Ideally, these built forms must be oriented parallel to the prevailing wind direction to ensure better ventilation and cleaner air. Lower age of air and better ventilation is observed surrounding the smaller fragmented

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Table 3.3 Ventilation study of a low rise & high rise new housing development in a Chinese city in Shenzhen, China. Source: Lau and Li (2006) Natural ventilation (South-East wind)

H = 5m (age of air)

H = 20m (age of air)

H = 40m (age of air)

Grey areas denote built areas. The large rectangular blocks in the S-E of the diagram are a low rise development. The two rows of smaller grey blocks in the N-W of the low rise development is a high rise development. Smaller narrow grey blocks in the N-W denote a high rise development. The blue areas in the above graphs denote low age of air indicating well ventilated areas with fresh air. The red parts denote high age of air indicating less ventilated areas with stagnant air. Red, orange, yellow, green, light blue, blue and dark blue denote age of air in descending order

H = 5m (velocity)

H = 20m (velocity)

H = 40m (velocity)

In the three diagrams above concentrated areas denote higher wind velocities. The short arrow strokes indicate low and long arrow strokes indicate high velocities. The red, yellow, green and blue strokes denote wind velocity in descending order

building shapes and footprints. The areas surrounding larger blocks show high age of air and comparatively poor ventilation. In all three graphs, the row of high-rise building further away from the wind direction have a higher age of air spread in larger compositions compared to the row of buildings closer to the wind direction. Observations confirm that the block size, orientations, building heights and distance from wind source affect the age of air, ventilation and air quality surrounding those buildings especially on the leeward side. The analysis can be further substantiated by the qualitative data gathered among occupants in high-rise living in Hong Kong (Lau, 2002). The general conceptions of occupants are that the apartments in higher floors are preferred due to better quality of environment – such quality can be specifically referred to as the air quality and reduced noise levels.

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The wind velocity graphs further confirm the observations made on the age of air distributions at varying heights. Lower wind velocities are observed at low height levels. Low wind velocities are also observed in the leeward sides of high-rise buildings, causing high age of air, poor ventilation and air quality in those areas. Also, when the distance from wind source increases, the velocities decrease indicating the higher age of air surrounding built forms further away from the wind source. In order to enhance the wind environment in Hong Kong, an air ventilation issue has been included in the Hong Kong Planning Standards and Guidelines. A set of qualitative guidelines and a framework for carrying out air ventilation assessment have been formulated on the basis of the air ventilation assessment study recommendations. The guidelines incorporated in the Hong Kong Planning Standards and Guidelines are to strengthen the urban design guidelines for better air ventilation. The guidelines were developed according to the results of “Feasibility Study for Establishment of Air Ventilation Assessment System” (the AVA Study) was conducted and completed in 2005. In addition to the guidelines, a technical guide for air ventilation assessment (AVA) has been issued by the Planning Department of Hong Kong (2005). AVA can be used to compare the air ventilation impacts of different design options and to identify the potential problem areas for design improvements. This technical guide specifies three steps in conducting AVA, i.e. expert evaluation, initial study and detailed study. The expert evaluation is a qualitative assessment based on the guidelines provided in Hong Kong Planning Standards and Guidelines, while the initial study will refine the expert evaluation and the detailed study will conclude the AVA. The AVA technical guide recommends using wind tunnel as the tool for carrying out both initial and detailed study. However, the use of Computational Fluid Dynamic (CFD) will be permitted in the initial study (Hong Kong Planning Department, 2005). The examples of using CFD simulation in AVA study are presented in Table 3.4. This study highlighted the air ventilation benefits of raising the podium level of residential buildings. The table shows the comparison of mountain and valley breezes for base case and proposed designs. According to the mountain/valley breeze simulations, we can find that the mountain can create local winds that vary from day to night if there is no background wind, which can also increase the air flow around the buildings in the mid-level. During the daytime, the air near the mountain surface can be heated up and higher than the free air far away at the same height due to the solar radiation. Thus the warm air moves up along the slopes. While during the night-time, as the mountain surfaces cool down, the cold breezes can be formed and flow down the slopes. The proposed new podium can enhance the air flow through the building. It can be imagined that the building region can benefit from the mountain breezes by bringing the cooled air at night-time on hot days. The thermal environment can be improved and energy can be saved (Li & Yang, 2008).

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Table 3.4 Building shapes and re-entrants. Source: Lau and Baharudin

Prevailing layout plan prior to year 2003. Narrow and deep re-entrant shapes bring in minimal light and ventilation in the well type shape high-rise towers. This is also the typical shape of Amoy Gardens Residential Development where the outbreak of SARS occurred in March 2003. By April 2003 there were a total of 321 cases of SARS in Amoy Gardens (Hong Kong Department of Health, 2003)

New layout plans after year 2003. Different re-entrant shapes are seen above creating shallow wider shaped reentrants. Better light and ventilation is created for better environmental quality and hygiene

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3.4.2 Daylighting and Ventilation Within High-Rise Housing Units The air ventilation and daylight penetration into individual housing units play an important role in high-rise residential building designs. Many factors determine the daylight quality within housing units. Study done by the students of the final year Bachelor of Arts in Architectural Studies, Department of Architecture University of Hong Kong (2006/2007) reveals several factors that determine the daylight quality within housing units. Table 3.5 illustrates the types of building footprints found in high-rise residential buildings in Hong Kong and the evaluation of the lighting quality within a selected individual housing unit. A qualitative appraisal of the lighting quality in individual rooms of the housing unit is done by its occupant. This is combined with a quantitative – daylight simulation for the residential units showing the distribution of lighting within the spaces. The distribution of lighting quality significantly varied across the building types and spaces/rooms within the individual units. Lack of sufficient lighting and ventilation in the kitchen and washrooms were a common observation. Obstructions to light due to windows being covered for better privacy and furniture layout were also observed as barriers to daylighting within the spaces. Some spaces have no windows at all and may be for the purpose of storage. But due to the lack of sufficient living space such spaces are also used for habitation. On most occasions, occupants use artificial lighting in such spaces even during day-time. Small window sizes and fixed glazing were also commonly noted as causes for poor light and ventilation. Further, it can be observed that most kitchen and toilet spaces in high-rise buildings are ventilated via “Re-entrant light wells”. These are equivalent to a light well with the main purpose of bringing in light and ventilation (Lau et al., 2006). Residents most often use the window opening into re-entrants for drying clothes, etc. The inlet and outlet water pipes to kitchen and toilets are located along the re-entrant spaces. The mechanical ventilation outlets are also located along these re-entrants that act as a shaft for bringing in fresh air as well as outlets for foul air from toilets and kitchen. The building shapes play a major role in determining the re-entrant shapes (see Table 3.5 for building shapes and re-entrant shapes). Most often, the reentrants are too narrow and inadequate for bringing in light and ventilation. Wider, more open re-entrant shapes are needed for sufficient light and ventilation. The size, number and positioning of windows, the floor area of space, windowfloor area ratio, the shape of the room and depth of space from window, internal reflectance of materials and finishes, the building footprint shape, external obstructions, building orientation, obstructions caused by neighbouring towers and distance between towers, external barriers to wind and daylight such as hills and internal furniture layouts all affect the quality of ventilation and daylighting within residential units in high-rise towers (Final Year Bachelor of Arts in Architectural Studies Students, 2006/2007; Lau et al., 2006). A common issue is windows placed within the visibility range from neighbouring blocks cause lack of privacy. As a result, most windows are kept closed and covered using opaque materials such as shades, curtains, etc. blocking light and ventilation into the housing units. Tables 3.6 and 3.7 illustrate the case studies and respective daylight analyses.

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Table 3.5 Daylight study of high rise housing. Sources: Chan (2006/2007), Chow (2006/2007), Ho (2006/2007) Description

Well type

Cluster shape

Crucifix shape

Location

Full wing building, Hung Hom, Kowloon

Whampoa garden, Kowloon

Lok Fu estate, Kowloon

Ariel view

Building foot print

Individual housing unit layout plan

Daylight analysis

Issues relating to lighting and ventilation

Uneven day light distribution in several spaces within the block is caused due to window sizes and numbers, the floor area, window-floor area ratio, the location of windows, shape of building foot print, interior furniture layout and distance between blocks and block layout, contextual barriers such as hills, obstructions from other buildings also determine the lighting quality and ventilating inside housing units of high rise blocks. Windows facing neighbouring blocks are being constantly kept closed due to lack of privacy, thereby does not serve the purpose of brining in light and ventilation

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Table 3.6 Day light study of high rise housing. Sources: Chan (2006/2007), Cheung (2006/2007), Kei (2006/2007), Wong (2006/2007) Trident-3 type

‘Y’ Shape

Irregular shape

Public residential development Shatin, new territories

Chen on public housing estate Tsing Yi, new territories

Private residential Classical gardens private housing estate, development, Tai Po, Ap Lei Chau, new territories new territories

Well type

Deeper spaces from the window have less lighting Bay windows and full height windows affect better lighting quality in the internal spaces

In addition, Lau and Baharuddin (2006) investigated the effect of relaxation of room height as a means for improving daylight conditions. The study investigated the relaxation of room heights from 2,800 to 3,650 mm and sustainable design features of proposed residential building located at Mid-Levels, Hong Kong.

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Table 3.7 Day light study for residential development in mid-levels, Hong Kong – the effects of relaxation of room height. Source: Lau (2006) Case 1 − base case

Case 2 − room 1

Case 3 − room 2

Window size- 1,250 × 1,200 mm

Window size- 1,250 × 1,200 mm

Window size- 1,250 × 1,700 mm

Room height- 2,600 mm

Room height- 3,450 mm

Room height- 3,450 mm

15

Daylight Factor (%)

12.5

10

Base Case Room 1 Room 2

7.5

5

2.5

0

0

0.5

1 1.5

2

2.5

3

3.5

4

4.5

5

Distance (m)

When window size remains the same and the room height is increased the day light within the room is improved but not a very significant improvement is seen. But when window size and room height is increased there is a significant increase in the daylight quality within the room. Also graph shows that in Room 2 with higher room height and larger window size the day light factor shows significant increase

The simulations were carried out based on the parameters: date 21 Dec (winter solstice), time 9:00 am, sky condition: overcast sky, design sky 8,500 lux. This analysis is regarded as the worst-case scenario for daylight calculation. Three cases are presented in Table 3.8. The study revealed that an increase in room height has some effect on improving the daylight quality within a room. In addition, the increase of window height can make a significant contribution to the daylight quality within the room.

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Table 3.8 Study of factors influencing occupants’ satisfaction of open space in high density public housing in Hong Kong. Source: Coorey (2007) Lower density

Medium density

Higher density

<1,200 per ha

1,200–2,200 per ha

2,200–3,200 per ha

Lai Kok Estate (13 floors)

Choi Hung Estate (8–20 Floors) Fortune Estate

Upper Wong Tai Sin Estate (10–41 Floors) Lower Wong Tai Sin Estate (15–32 Floors) Ping Shek Estate (8–28 Floors)

(20–40 Floors)

Social qualities 23.9%

Social qualities 10.2%

Social qualities 7.9%

Physical qualities 10.5%

Physical qualities 26.4%

Physical qualities 17.7%

Above results show that 23.9% variance in open space satisfaction is explained by the social quality of open space in the lower density cases, but in the higher density cases only 7.9% variance in open space satisfaction is explained by its social qualities In contrast in the lower density cases only 10.5% variance in occupants’ satisfaction of open space is explained by its physical qualities, but in the higher density cases 17.7% variance in satisfaction is explained by its physical qualities In the above physical qualities the climatic comfort in open space (CLIMCOMF) is a significant indicator for open space satisfaction

3.4.3 Occupants’ Satisfaction of Open Space in Tall Residential Buildings Outdoor living space of high-rise residential buildings is equally important. Adequate provision of open space, greenery, vistas and visual corridors is a critical issue in the light of high land prices and the general lack of space between and around tall buildings. Open spaces and landscaping on podiums are design measures taken to improve resident perceptions of open spaces, views and greenery. Open spaces located close to highways, roadways, and transport nodes create poor environmental quality due to noise, dust and smoke emissions. In other words, it can be argued that even if open spaces are provided within residential blocks or outside in close proximity to homes, if its quality does not meet the demands and satisfaction of its users, such open spaces may not be efficiently utilised. Podium open spaces and sky gardens create a barrier from traffic and pollution at road levels. Yet, being surrounded by high-rise buildings these spaces have a

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tendency to trap pollutants due to a lack of cross ventilation and high building mass. The lack of green cover, trees and hard landscaping may contribute to poor micro climatic conditions in the outdoor spaces of high-rise developments (Tan & Fwa, 1992; Wilmers, 1990/1991). But, people are forced to use these open spaces despite its poor environmental quality. Study by Davies (1998) has shown that the most popular form of recreation among Hong Kong residents is the use of passive local open spaces. It is observed that the majority of users of such open spaces are elderly, low income groups whose accessibility to district open spaces and country parks may be limited. Study of open space satisfaction among occupants of high-rise public residential estates in Hong Kong by Coorey (2007) shows that satisfaction of open space is primarily dependent on the physical qualities as opposed to its social qualities. The physical qualities such as climatic comfort, maintenance, facilities and provisions were identified as having important implications on their overall satisfaction. The study involved 600 questionnaire interviews conducted in 6 high-density public housing estates in Hong Kong. Respondents evaluated the physical and social quality of open space and their levels of satisfaction in 15 open spaces including those on podiums and ground level in the six high-rise developments. A comparison of open spaces located within public housing of varying density showed that occupants in higher density developments considered the physical qualities of open space such as climatic comfort, provision for open space and maintenance as having higher impact on their overall open space satisfaction. Respondents living in the lower density cases tend to consider the social qualities such as safety, crowding, privacy and interaction to have a higher implication on their open space satisfaction (Coorey, 2007). The study highlighted the importance of environmental quality for optimum satisfaction of open spaces located within high-rise residential developments. It further highlighted that open space satisfaction among occupants living in higher density cases was significantly influenced by its environmental quality as opposed to its social qualities. Such open spaces play a critical role in the lives of residents living in high-rise buildings as they are their only means of escape from the otherwise built up urban setting. Additionally, its importance for the elderly and low-income groups, specifically draws on the need for optimizing the environmental quality of open spaces in high-rise developments. An increase in respondents’ satisfaction with climatic comfort in open space is shown when the number of trees, the proportion of greenery is higher and the sky view factor is low due to taller buildings adjacent to smaller narrower open spaces (Coorey, 2007).

3.4.4 Noise Pollution Noise pollution is a common environmental quality issue associated with mixed use and high connectivity with transport networks. Taller buildings with residences in the higher floors are preferred due to less noise in the higher floors (Lau, 2002). Also, elevated walkways and podiums serve as design principles for segregating

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pedestrian routes from noise and pollutant sources at street and ground levels. The podiums act as buffers from noise at ground level. The building clusters in Hong Kong are well integrated through elevated walkways subways and podiums that induce people to walk through buildings rather than being exposed to the fumes and noise of vehicular traffic at road levels. Study of external noise measurements in the surrounding areas of an arts performing school showed that high traffic noise reflectance was caused by the façade effect and canyon effect due to high-rise built forms running parallel to the roadways (Lau, 2006). Measurements were taken alongside two roadways on opposite sides of the arts school. One roadway has high-rise buildings located alongside it while low-rise buildings frame the roadway on the opposite side. Higher noise levels are observed from the roadway with high-rise buildings. The facades of high-rise built form act as reflectors for noise sources from vehicular traffic. The taller building forms create a canyon effect causing higher noise levels. It can be suggested that the building facades, orientations with the noise sources and its noise reflectance and absorption values must be manipulated. This can be done by orientating the buildings so that it does not obstruct and reflect noise. Instead, it disseminates the noise and avoids a canyon effect. The materials of the facades should be of less reflectance and higher absorption values. In addition, trees and shrubs can be introduced as noise screens alongside roadways. Zoning at planning stage must be done with an awareness of the noise sources and noise reflectors in the surrounding context. Habitable spaces can be buffered by elevating the units above the noise source levels. Soft landscaping features such as water fountains can be used to mask and create distraction from traffic noise.

3.5 Conclusion Although tall residential buildings have many social and environmental implications, Hong Kong’s topography and continuous increase in population have propelled the planning and design of Hong Kong’s built form clearly in the direction of tall buildings. But how tall and how to design such tall building is the question of concern. The general policy and regulations provoke taller buildings. But the regulations and attention of Hong Kong designers are turned towards more sensitive design measures that will balance the demand for taller buildings with more sensitive, sustainable and liveable design features. The critical implications for building tall are mainly associated with poor air quality, lack of wind ventilation in a macro context of a high-rise city as well as the micro context within the residential units or apartments. Poor daylighting quality within tall buildings is a pressing issue for tall buildings. The lack of open space and the poor environmental quality in such open space is another issue that impacts the quantity and quality of open space among highrise occupants. The noise levels due to reflectance from high-rise towers caused by façade and canyon effects are also a challenge for zoning, orientations and design.

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Such issues bring about specific criteria for zoning, planning and design in tall building contexts. This chapter highlighted some of the design issues and possibilities. Acknowledgments The author acknowledges the research assistance given by Dr. Shaleeni B. A. Coorey and Dr. Baharuddin of Department of Architecture, the University of Hong Kong. The useful information and data provided by Professor Y. Li and Dr. Lina Yang of Department of Mechanical Engineering, the University of Hong Kong, the Chinese University of Hong Kong- Air Ventilation Assessment Project Team, Hong Kong Planning Department, Hong Kong Buildings Department, Hong Kong Mass Transit Rail Corporation, and the Final Year Bachelor of Arts Students 2006/2007 of the Department of Architecture, University of Hong Kong; Chan K. H., Cheung H. F., Chow K. Y., Kei Y. S., and Wong Y. N. are gratefully acknowledged.

References Burton, E. (2000). The compact city: Just or just compact? A preliminary analysis. Urban Studies, 37(11), 1969–2007. Chan, K. H. (2006/2007). Daylight analysis: Residential buildings in Hong Kong. Unpublished Bachelor of Arts in Architectural Studies Final Year ProjectWork, Department of Architecture, The University of Hong Kong, Hong Kong. Cheung, H. F. (2006/2007). Daylight analysis: Residential buildings in Hong Kong. Unpublished Bachelor of Arts in Architectural Studies Final Year ProjectWork, Department of Architecture, The University of Hong Kong, Hong Kong. Chief Executive. (2006–2007). 2006–2007 policy address by chief executive. Hong Kong: Hong Kong SAR Government. Last accessed December 15, 2009, from http://www.info.gov.hk/gia/general/200610/11/P20061010101_print.htm Chinese University of Hong Kong. (2005). Feasibility study for establishment of air ventilation assessment system-executive summary. Hong Kong: Department of Architecture, Chinese University of Hong Kong, Hong Kong. Ching, L. Y. (2005). Sustainable development of tall buildings in Hong Kong. Paper presented at the tall buildings: From engineering to sustainability, Hong Kong. Chow, K. Y. (2006/2007). Daylight analysis: Residential buildings in Hong Kong. Unpublished Bachelor of Arts in Architectural Studies Final Year ProjectWork, Department of Architecture, The University of Hong Kong, Hong Kong. Coorey, S. B. A. (2007). Design of open spaces in high density zones: Case study of public housing estates in Hong Kong. Unpublished PhD thesis, The University of Hong Kong, Hong Kong. Davies, L. (1998). Study of leisure habits and recreation preferences and review of chapter four of the Hong Kong planning standards and guidelines. Final Report, Planning Department, Hong Kong. Final Year Bachelor of Arts in Architectural Studies Students – Department of Architecture University of Hong Kong. (2006/2007). Daylight analysis: Residential buildings in Hong Kong. Unpublished Final Year Project, The University of Hong Kong, Hong Kong. Fung, B. C. K. (2001). Planning for high density development in Hong Kong. Hong Kong: The Planning Department of Hong Kong, Hong Kong. Givoni, B. (1998). Climate consideration in building and urban design. New York: Van Nostrand Reinhold. Google Earth. (2008). IFC, Kornhill, Telford, union square images in google earth. Last accessed December 15, 2009, from http://www.googleearth.com Haccou, H. A. (2007). MILUnet: Multi functional intensive land use – Principle, practices, projects, policies – Towards sustainable area development. Harbiforum Foundation, The Netherlands. Ho, K. Y. (2006/2007). Daylight analysis: Residential buildings in Hong Kong. Unpublished Bachelor of Arts Final Year Project Work, Department of Architecture, The University of Hong Kong, Hong Kong.

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Hong Kong Department of Health. (2003). Outbreak of severe acute respiratory syndrome (SARS) at Amoy Gardens, Kowloon Bay, Hong Kong – Main findings of the investigations. Department of Health, Hong Kong. Hong Kong Environmental Protection Department. (2006). Air quality in Hong Kong 2006. Hong Kong Environmental Protection Department, Hong Kong. Last accessed December 15, 2009, from http://www.epd-asg.gov.hk/english/report/files/aqr06e.pdf Hong Kong Mass Transit Railway Corporation. (2008). MTR properties. Hong Kong Mass Transit Railway Corporation, Hong Kong. Last accessed December 15, 2009, from http://www.mtr.com.hk/eng/properties/prop_dev_index.html Hong Kong Planning Department. (2005). Technical guide for air ventilation assessment for developments in Hong Kong. Hong Kong Planning Department, Hong Kong. Last accessed December 15, 2009, from http://www.pland.gov.hk/p_study/comp_s/avas/ papers&reports/technical_guide.pdf Hong Kong Planning Department. (2006a). Planning department annual report 2006. Hong Kong Planning Department, Hong Kong. Hong Kong Planning Department. (2006b). Hong Kong planning standards and guidelines. Hong Kong Planning Department, Hong Kong. Hui, S. C. M. (2000). Low energy building design in high density urban cities. World Renewable Energy Congress VI, Brighton. Jenks, M. (2000). Sustainable urban form in developing countries? In M. Jenks & R. Burgess (Eds.), Compact cities sustainable urban forms for developing countries. London: Spon Press. Kei, Y. S. (2006/2007). Daylight analysis: Residential buildings in Hong Kong. Unpublished Bachelor of Arts Final Year Project Work. Department of Architecture, The University of Hong Kong, Hong Kong. Lau, S. S. Y. (2002). A survey on residents’ responses to high rise living in Hong Kong. Centre for Architecture and Urban Design for China and Hong Kong, Department of Architecture, The University of Hong Kong, Hong Kong. Lau, S. S. Y. (2006). Traffic noise measurement for the school of performing arts. Department of Architecture, The University of Hong Kong, Hong Kong. Lau, S. S. Y., & Baharuddin. (2006). Sustainable building design: Residential development, midlevels, Hong Kong. The University of Hong Kong, Hong Kong. Lau, S. S. Y., Baharuddin, Lee, W. Y. W., Leung, D. K. C., Ye, A. M., Amato, A., et al. (2006). Reconsidering daylighting design parameters for tall buildings in densely built city. Architectural Science Review, 49(3), 285–294. Lau, S. S. Y., & Coorey, S. B. A. (2007). Hong Kong: MILU and how it is perceived. In H. A. Haccou, T. Deelstra, A. Jain, V. Pamer, K. Krosnicka, & W. R. De (Eds.), MILUnet: Multi functional intensive land use – Principle, practices, projects, policies – Towards sustainable area development. Harbiforum Foundation, The Netherlands. Lau, S. S. Y., Ghiridharan, R., & Ganesan, S. (2003). Policies for implementing multiple intensive land use in Hong Kong. Journal of Housing and the Built Environment, 18(4), 365–378. Lau, S. S. Y., & Li, Y. (2006). Environmental performance analysis: Proposed luxury residential development in Shenzhen, China. The University of Hong Kong, Hong Kong. Li, Y., & Yang, L. (2008). Ventilation study of residential development at IL 2510 & extension, 15 magazine gap road, mid-levels, Hong Kong. Unpublished Report, The University of Hong Kong, Hong Kong. Masnavi, M. R. (2000). The compact city in practice: The new millennium and the new urban paradigm. In K. Williams, E. Burton, & M. Jenks (Eds.), Achieving sustainable urban form (pp. 64–73). London: E&FN Spon. Newman, P., & Kenworthy, J. (1992). Is there a role for physical planners. Journal of the American Planning Association, 58, 353–362. Ng, Y. H. (2008). Protesters demand review of ‘wall effect’ projects, South China morning post. Last accessed December 15, 2008, from http://proquest.umi.com/

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Planning department of Hong Kong. (2005). Technical guide for air ventilation assessment (AVA) for developments in Hong Kong. Planning Department of Hong Kong, Hong Kong. Last accessed December 15, 2009, from http://www.pland.gov.hk/ pland_en/p_study/comp_s/avas/papers&reports/technical_guide.pdf Tan, S., & Fwa, T. (1992). Influence of pavement materials on the thermal environment of outdoor spaces. Building and Environment, 27(3), 289–295. Williams, K., Burton, E., & Jenks, M. (2000). Achieving sustainable urban form. London: E&FN Spon. Wilmers, F. (1990/1991). Effects of vegetation on urban climate and buildings. Energy and Buildings, 15–16, 425–431. Wong, Y. N. (2006/2007). Daylight analysis: Residential buildings in Hong Kong. Unpublished Bachelor of Arts Final Year ProjectWork. Department of Architecture, The University of Hong Kong, Hong Kong. Wong, O. (2007). Call for law against ‘wall effect’ fails, South China morning post. http://proquest.umi.com/ Wu, M. (2005). Policies and planning of tall buildings in Hong Kong. Paper presented at the tall buildings: From engineering to sustainability, Hong Kong. Xue, C. Q. L., Manuel, K. K., & Chung, R. H. Y. (2001). Public space in the old derelict city area – A case study of Mong Kok, Hong Kong. Urban Design International, 6(1), 15–31. Yueng, C. (2006). Asia’s walled city’ leaves – Residents longing for air, the standard. Accessed December 15, 2009, from http://www.thestandard.com.hk/

Chapter 4

The Planning and Design of Environmentally Sustainable High-Rises Wenjian Zhu and Rebecca L.H. Chiu

4.1 Introduction Subsequent to the publication of the Brundtland report on sustainable development, there has been a global movement to search and achieve urban development that “meets the needs of the present without compromising the ability of future generations to meet their own needs” (World Commission on Environment and Development, 1987). Among the various sustainable urban forms advocated, the concept of compact city development has become increasingly popular as a spatial strategy to counteract the environmental ills of urban sprawl (Jenks, Burton, & Williams, 1996a; Jenks & Burgess, 2000). The compact city concept has a variety of definitions but in general, it refers to a well-defined urban mode with relatively high density, mixed land use pattern, and an efficient public transport system (Jenks et al., 1996a; Jenks & Burgess, 2000). It also argues that high population and building densities are financially conducive for the operation of an efficient public transport system, which is environmentally friendlier (Newman & Kenworthy, 1989a). To save on the use of land, the model also encourages multi-storey residential buildings, though the norms vary across different urban cultures. In fact, perceived from the perspective of environmental sustainability, housing development is a process that involves the change of natural resources, via labour power, into liveable spaces. The housing units produced in turn provide shelter, use and reproduce energy, and generate waste to the wider area (Bhatti, 1994; Chiu, 2000; Rydin, 1992). From this perspective, housing has significant implications for the pursuit of urban sustainability as housing is one of the most important components of the built environment. The sustainability concerns of housing in the environmental dimension are the impacts of residential activities on the ecological system, and the quality of the living environment of the inhabitants. Put in other words, the meeting of the housing needs and demands of the population should be qualified by the capacity of the natural environment to make such provisions (Bhatti, 1994; Chiu, 2000; Rydin, 1992). The tenet of environmentally sustainable housing W. Zhu (B) College of Architecture and Urban Planning, Shenzhen University, Shenzhen, China e-mail: [email protected] B. Yuen, A.G.O. Yeh (eds.), High-Rise Living in Asian Cities, C Springer Science+Business Media B.V. 2011 DOI 10.1007/978-90-481-9738-5_4, 

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development is thus to minimize the negative environmental impacts of housing activities and to simultaneously improve the environmental quality of housing for the residents. Whether residential buildings in the form of high rises are more environmentally sustainable than low rises have been debatable (see, for example, Rudlin & Falk, 1999; Thomas & Cousins, 1996; Troy, 1996a). Inevitably, both building forms and the liveability they bring about incur environmental advantages as well as disadvantages. While policy makers should take the sustainability performance into account when formulating housing and urban strategies, it is also important and necessary that research is undertaken to improve the environmental sustainability of residential buildings, be they high rises or low rises. The purpose of this chapter is therefore to explore ways to enhance the environmental sustainability of residential high rises at the planning and design stages. Following this introduction, the Chapter first examines the sustainability advantages and disadvantages of residential high rises. It then discusses planning strategies and design principles which can enhance environmental sustainability, citing examples from Hong Kong, a city renowned for its high density living and skyscrapers.

4.2 Sustainability Advantages 4.2.1 Less Land Consumption Housing and residential land use is the largest consumers of urban space. High-rise and high-density development model could save land consumption, preserving more natural and green space and thus maintaining ecosystem dynamics (Alberti, 2000; Bookchin, 1986; Rudlin & Falk, 1999). Furthermore, because sites of cities are often chosen or expanded to exploit the agricultural hinterland, urban sprawl tends to consume high quality agricultural land. Intensification of land use by building high-rise is thus an important way of reducing sprawl onto farmland (Jenks & Burgess, 2000; Pun, 1994). Despite an average population density of 6,352 persons/km2. (Census and Statistics Department, 2007), the developed areas of Hong Kong only occupied 23.8% pf the total land area, whereas the country parks alone accounted for 38% (Hong Kong SAR Government, 2007).

4.2.2 Higher Energy Efficiency and Lower Resource Consumptions For housing the same number of residents, a high-rise block consumes less building material as flats share foundations, roofs and partition walls, compared with a detached dwelling. High rises are also potentially more energy efficient since they have less exposed wall area and the dwelling units often have no heat-loss roof. This is also true for mixed-use buildings where workspace and shops are located in the lower floors, when compared with single-storey structures (Rudlin & Falk, 1999). High rises also reduce the cost of environmentally friendly services. Owens (1986)

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and Travers (2001) claimed that higher-density settlements are better able to afford recycling programmes, such as waste collection, facilities recovering waste materials, the marketing of waste materials, and the control and treatment of effluents and other forms of pollution. High-rise development also facilitates the reduction of transport energy consumption. The studies of Newman and Kenworthy (1989a, 1989b) examined the relationship between residential density, the viability of public transit systems, and automotive fuel usage, and concluded that higher residential densities enhance the viability of public transport. Other studies also argued that higher residential densities enabled mixed land-uses, and better job-housing balances, thus reducing automobile use (Cervero, 1998). Thus, high rises indirectly lead to a reduction of the emission of carbon dioxide (CO2 ) and nitrogen oxides (NOx ) that contribute to the greenhouse effect, air pollution and noise pollution (Barter, 2000; Brown, 1987; Rudlin & Falk, 1999).

4.2.3 Better Liveability High density attributed by high rises has the potential of providing a diversity of easily accessible services to meet the needs of different household types of different interests and lifestyles (Forsyth, 1997; Jenks, Burton, & Williams 1996b). Owing to the agglomeration of inhabitants, a large number of services may be located within walking distance form dwellings and in close proximity to each other. This also enhances the potential for walking and cycling, thereby enabling various population groups (children, teenagers, the elderly, the handicapped, and those without cars) to avail themselves of resources independently. Also, higher densities meant that more people could be housed or could work closely together, requiring shorter lengths of cables, pipes and sewers, bus routes, roads and also fewer but may be larger commuting facilities, such as shops, hospitals and schools (Pun, 1994; Travers, 2001).

4.3 Sustainability Disadvantages 4.3.1 Insufficient Urban and Housing Land Compact development frequently implies savings in the use of urban and agricultural land. However, Pun (1994) argued that if high-rise and high-density buildings had to be cramped into limited urban area, they posted great pressure to a city’s infrastructure system. With limited urban area, housing, public facilities and infrastructures needed to compete for land for development, and such competition mostly resulted in the deficiency of facilities, living space and highly congested townscapes. Gordon and Richardson (1997) also pointed out that the high prices of urban land caused by compactness might lure governments and developers to either use low value farmland, or to cut back the hills, or even to reclaim land from the sea to generate profits, thus unnecessarily damage the natural ecosystems.

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4.3.2 High Operation Energy Compared with traditional low rises, the embodied energy in the operation of highrise building is likely to be very high because of the higher levels of investment in fixtures and fittings (Rydin, 1992). Troy (1996a) pointed out that larger buildings, especially offices and apartment blocks, had to consume large amounts of energy for lighting, heating, cooling and air-conditioning, especially for the operation of lifts. Further, low rises are more likely than high rises to be able to meet the energy requirements using renewable sources such as wood and solar energy. As well, lowrise development is more likely to be able to maximize advantages from orientation and design due to less structure restriction (Troy, 1996a, 1996b).

4.3.3 Less Desirable Living Environment In the review of the environmental effects on intensification, Paehlke (1991), Thomas and Cousins (1996) acknowledged that taller buildings would be more exposed to wind and day lighting infiltration. In a compact living environment, contacts with the natural environment may also be lost (Hitchcock, 1994). Furthermore, residents are forced to interact with strangers in high rise buildings such as in the corridors or in the lifts. Close proximity could lead to conflicts as the lifestyle may diversify – especially in mixed-use areas. The feeling of overcrowding in the public realm, noise, pollution, loss of identity and reduction in privacy are other problems (Williams, Burton, & Jenks, 2000). Putting these advantages and disadvantages into the context of environmental sustainability, high rises giving rise to a more compact urban form can shorten travel distance, reduce the emission of greenhouse gases, and reduce energy consumption with the greater use of public transport. High rises can also mitigate the use of natural land and other resources, and lessen the need for the geographical expansion of infrastructure, thus better protect the natural ecology. They may also shield residents from air pollution, noise and dust from vehicle exhausts. However, the disadvantages of environmental impacts of high rises also abound. This may include higher energy consumption during construction and the operation of the buildings, the restrictions in the use of renewable sources, and the need to use more energy intensive material such as concrete. While high rises can shield air and noise pollution, they may also create heat island and hamper the dispersion of pollutants.

4.4 Planning Strategies and Design Principles for Enhancing Environmental Sustainability Obviously, the planning strategies and design principles of high rises are closely associated with the sustainability advantages and disadvantages discussed above. For instance, a planning strategy of maximizing open space in the development site would improve natural ventilation and reduce the external adverse impacts of the

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use of air conditioner. The planning and design of high rises are certainly complex and intricate matters, and need to take many factors and trade-offs into account. This section discusses the major planning strategies and design principles, which contribute to achieving the environmental substantiality of high rises: minimizing the negative environmental impacts of their activities and improving the quality of the living environment of the inhabitants.

4.4.1 Vertical Organization of Land Uses Since residential land use is the largest consumer of urban space, the wider use of residential high rises enables urban development to be more sustainable by reducing the demand on land. Residential high rises can be further developed to accommodate mix uses to reduce travel trips, thus reducing energy consumption. Traditionally, most Western mixed-use housing developments are planned horizontally with integrated community and retail facilities in the neighbourhood. But in Asian cities such as Hong Kong, Tokyo, Singapore and Shanghai, more and more residential super/mega structures are planned and designed to accommodate a multiple of uses. There are usually four vertical components (Fig. 4.1). At the top are the residential floors, below which is usually a massive podium designed as green open and social space for the exclusive use of the residents. The podium also effectively blocks street noise and dust. Below the podium level are the amenity floors, comprised of one to three levels of retail facilities (e.g. shops, restaurant), community facilities (e.g. community centre, kindergarten) and sometimes a public transport

Fig. 4.1 Vertical organization of land uses

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interchange. These commercial floors reduce the need to travel for facilities and also block residents from the noise and exhaustive gases from vehicles. Furthermore, these facilities could be shared by other users living or working in the district. If the commercial floors of other housing projects are linked by footbridges, the networks of pedestrian walkways could be enhanced. At the basement level are the subway and car parks, which are divided into residents’ and shoppers’ sections. The vertical organization of land uses also has different varieties, such as residential floors, plus podium and car park, or residential floors plus sky garden, commercial/entertainment facilities and car park. The vertical organization of land uses increased development intensity, and enlarging the accommodation capacity of housing sites. However, the higher concentration of population, involving a more diverse mix as well, also incurs greater pressure on the infrastructure and transport facilities. In Zhu’s (2008) study of Hong Kong’s three public housing estates, comprised of high rise blocks of 22–41 storeys, it was found that the residents’ satisfaction rates for the provision of public transport services and community facilities were only 44.8% and 48.5% respectively. The problems encountered by residents included insufficient bus routes and bus frequency, and inadequate community facilities, such as market and youth centres, to meet their needs. These planning problems certainly could not be fully ascribed to the public housing provider, as the work of other government departments and the market forces were at play. Indeed, the pursuit of higher density development through vertical organization of land uses requires more sophisticated planning and forecast skills, and greater co-ordination effort in infrastructure construction and service provision.

4.4.2 Energy-Efficient Envelope Design As earlier discussed, high-rise building forms on one hand can save energy because of the shared foundations, roof, and partition walls, but on the other, they consume high levels of energy due to the operation of lifts, and the use of air conditioning to combat bad ventilation. There is not much room to significantly reduce energy consumed by lifts except by restricting unnecessary movements with computer programming and designing convenient pedestrian system to encourage the use of staircase. However, the design of the building envelope has drastic influence on the indoor microenvironment, which in turn affects the energy needed for heating, air conditioning and lighting. The envelope of the building consists of the exterior walls, the roof, floors, windows and doors. In addition to giving the envelope the desired appearance, the envelope must withstand the stresses to which it is exposed and also must protect the enclosed space against the local climate. The first consideration of envelope design is thermal comfort. In cold climate region, the function of thermal insulation is to obstruct indoor heat loss through the envelope (Farahbakhsh, Ugursal, & Fung, 1998; Jaber, 2002). But in hot area, it may need to reduce the solar heat gain (Bojic & Yik, 2001; Niu, 2004). Today, with dynamic architecture and the proliferation of new materials, components

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and construction techniques, a great variety of new designs are possible (John, Clements-Croome, & Jeronimidis, 2005). But in fact, designs for exterior envelope for buildings have never been developed in a universal way due to the different local climate, developers and residents’ demands and architects’ creativities. However, two common measures are used to indicate the thermal performance of the envelope: the U-values (overall coefficient of heat transmission) in the colder region such as Europe; and the Overall Thermal Transfer Value in the hotter regions such as Asia. At the design stage, the building professionals need to consider the thermal insulation facing the outside or inside of the room, the thickness of thermal insulation and room orientation as they all affect the final thermal performance of the envelope (Bojic & Yik, 2001; Burnett, 2004; Cheung, Fuller, & Luther, 2001). Also, large and convex-shaped windows have become very popular to provide better views to the occupants. Consequently, solar heat gains or heat loss through glass has become another dominant air-conditioning or space heating load (Cheung et al., 2001). As well, the shading of buildings should also be considered because it also affects heat exposure. The second consideration of envelope design is ventilation and light penetration. Sufficient natural ventilation can remove the indoor air pollutants and smell, decrease the indoor temperature in hot region, and save energy consumed by air conditioning and fan movement. For sufficient natural light, it can enhance comfort and health, and save energy (Burnett, 2004). To estimate the ventilation and day-lighting in the design, Computational Fluid Dynamics technique and Daylight Factor approach are the analytical tools. But for high-rise residential buildings, many factors affect the design of ventilation and day-lighting and the final performance of individual dwelling units, such as local climate and environment, room orientation, building form and floor level. Several designs became popular in the recent years. One of these is windowvent designed with a pollutant filtration function, enabling constant air flow by self-regulating the opening degree in response to pressure differences (Niu, 2004). Double skin façade is another method, reducing up to 30–40% of the cooling energy of the conventional façade designs (Leigh, Bae, & Ryu, 2004). These designs were, however, originally conceived for office building. The applications and the costeffectiveness and acceptability in high-rise residential applications need further investigation. For designing the energy efficiency of the envelope, it is important to recognize at the outset the different requirements and conditions of the sites, such as the local climate. It is also necessary to consider and balance the overall function of the envelope. For example, though enlarging the window size could improve the daylight penetration, it may also lead to greater heat loss or solar heat gain. It may also be required to satisfy a number of lesser requirements such as colour, texture and porosity. Further, all of these must be achieved at an acceptable life time cost. In Hong Kong, energy-efficiency has not been attended to seriously in the envelope design of residential high rises. Statutory Overall Thermal Transfer Value has been determined for commercial buildings but not residential buildings. However, the Verbena Heights (Fig. 4.2), a social housing development completed in 1997,

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Fig. 4.2 Cantilevered canopies as shading devices adopted by Verbena Heights

pioneered an environmentally-responsible design. In this project, external shading devices, roof shading and thermal insulation strategies are employed to reduce internal overheating and the penetration of direct sunlight, thus reducing the cooling load. Light-shelves are provided to optimize day-lighting to the depth of room, lobbies and other communal areas (Hong Kong Housing Society, 1998). These experiences were unfortunately not publicized much at the time. In the past few years, nonetheless, the Hong Kong Housing Authority began to explore environmental designs for public housing estates. For instance, the solar heat gains of different façade and overhang were calculated to determine the thickness and shading device of the glass window. The wind walls from the second floor to the twenty-eighth floor were installed in order to improve the ventilation in the flats. Computational fluid dynamics simulations, wind tunnel tests and daylight simulation tools were used with the aim to improve sustainability (Hong Kong Housing Authority, 2001, 2002, 2003, 2004, 2005, 2006). So far, the public sector has been taking the head in these pioneering experiments.

4.4.3 Optimizing Spatial Configuration The attractions of high rises are often the views, the breeze and the privacy (as the units are high up in the sky) that residents can enjoy (Yuen, 2005; Yuen et al., 2006). The local climate (prevailing wind, solar angle) and site characteristics (e.g. hillside or waterfront site) are the important factors to be considered in the planning and design of housing. However, in a high-density built environment, tall buildings are usually close to one another. The close proximity may reduce airflow around buildings (Fig. 4.3) (Chow, 2004; Hui, 2001; Santamouris et al., 2001). It may also create the heat island effect (Giridharan, Ganesan, & Lau, 2004), or obstruct direct sunlight (Hui, 2001; Zhu & Lin, 2004), or block the views (Planning Department,

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Fig. 4.3 Optimization of spatial configuration to improve natural ventilation

2006). The microclimate issues (e.g. ventilation, day-lighting) are thus special factors in the planning and design of high rises. These concerns should be carefully considered not only in the planning and design stage of the buildings, but also in the formulation of the master layout plan or the spatial configuration of the whole development project. There are several important points to note. First, for the master layout plan, the distance between residential buildings should be maximized and the orientation of buildings should be tested to enhance air and sunlight permeability (Fig. 4.3). Also, building heights should be staggered to allow the wind and direct sunlight to penetrate through the project site. It would enable residents in rear buildings to share good views and better ventilation (Capeluto, Yezioro, & Shaviv, 2003; Planning Department, 2005, 2006; Zhu & Lin, 2004). Second, for building height design, the height should decrease towards the direction of major visual corridor or visual centre and the prevailing wind. As well, open spaces for children or youngster should also be designed in the windward direction whereas that for the elderly should be in the sheltered area. Large slab blocks creating wall effect should be avoided (Capeluto et al., 2003; Planning Department, 2005, 2006; Zhu & Lin, 2004). In fact, the above principles are generally adopted in the planning of public housing estates in Hong Kong (Hong Kong Housing Authority, 2007b). In Lei Muk Shue Estate, for example, residential blocks divided into two groups are planned to create an east to west wind tunnel to improve the flow of wind into the estate. In another estate – Hoi Lai Estate, besides dividing the blocks to create a wind tunnel, buildings facing the sea are shifted to allow the sea breezes into the estate (Zhu, 2008). Unfortunately, the private developers are interested in the more sustainable designs if they bring profit. Actually, in order to maximize plot ratios, the saleable area, the sea and/or hill views, many high rise residential projects in Hong Kong adopt a long slab building form, not only blocking the penetration of the wind to the rest of the site but also to the district behind. To mitigate the wall effects, the government has considered the use of regulatory tools such as planning controls or land lease controls (all land in Hong Kong is owned by the government) to guide building forms. Since 2006, air ventilation analysis has also been required for large housing projects (Housing, Planning and Lands Bureau and Environment, Transport and Works Bureau, 2006).

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However, dilemmas and difficulties are involved in the planning and design of outdoor natural light and sunlight of high rises, such as in the public housing estates of Hong Kong. On the one hand, in summer, sunshine with a high solar altitude angle can shine on and heat a larger area. As Hong Kong is located at low latitude, the peak solar altitude is up to 90◦ in summer. On the other hand, in winter, direct sunlight with a low solar altitude (about 48◦ at noon) is blocked by the high-rise buildings. Zhu’s (2008) study shows that the planning and design of public housing in Hong Kong does not sufficiently mitigate the effects of direct sunlight in summer, nor maximize the penetration of natural light and sunlight in winter. But in recent years, the government has used computer simulation techniques to analyze solar path and building shade in order to better define different types of open space in individual estates.

4.4.4 Sky Open Space and Landscaping Sufficient open space and green surfaces in dense urban area are indispensable for improving residents’ social lives, for preventing uncomfortable heat island effects and for saving energy (Edwards, 1999; Gehl, 1987; Giridharan et al., 2004; Roseland, Cureton, & Wornell, 1998). Unfortunately, open space and planted surfaces are disappearing because of intensive development in city area. Turning building podium or roof surfaces into open space with intensive greenery becomes an efficient and stabilizing choice. Vertical open space and planting have many potential sustainability benefits. The first benefit of roof or sky open space is to offer urban dwellers extra amenity and recreational space for healthy living and opportunities for social interaction. The sights, fragrances, the variety of sounds, colours and movement provided by plants add immeasurably to the richness of experience and quality of life. They also offer attractive views to the overlooking buildings (Architectural Service Department, 2007; Osmundson, 1999). To design vertical open space, apart from the need to provide convenient access, it is also important to avoid concealed areas as they may deter users (Architectural Service Department, 2007). The second benefit is the ability of greened urban areas to filter out particulates, which would stay on the plant as the air passes by, and would eventually be washed into the soil by rain. The foliage can also absorb gaseous pollutants lodging them in their tissue. Reportedly, green roofs can trap up to 95% of cadmium, copper and lead and 16% of zinc (Dunnett & Kingsbury, 2004). Furthermore, intensive green roofs, with trees and large shrubs presenting large three-dimensional surface leaf area will have a much greater effect than extensive green roofs with a relatively flat, two-dimensional vegetation profile (Architectural Service Department, 2007). The third important benefit is that green roof increases building insulation and energy efficiency. For example, by trapping an air layer within the plant mass, the building surface is cooled in summer and warmed in winter (Onmura, Matsumoto, & Hokoi, 2001). Also, by covering the building with vegetation, the summer heat is prevented from reaching the building skin; and in winter, the internal heat loss is prevented (Niachou, Papakonstantinou, Santamouris, Tsangrassoulis,

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& Mihalakakou, 2001). Finally, podium and sky gardens could improve wind permeability. Generally, sky gardens are located at the mid-level of buildings so as to reduce stagnancy on the leeward side, enhancing the performance of natural ventilation in the area (Yau, 2002). Some mitigation measures may be required to avoid excessively high wind speed at the sky gardens by using compact or porous windbreaks or windguards (Lu, Lo, Fang, & Yuen, 2005). In Hong Kong, podium open space has been a common feature in the private and public projects for quite some years. However, due to the higher maintenance cost and the need to hard pave outdoor space for some recreation activities (such as football pitch), some podium open spaces of public housing estates are short of greenery; while some podiums, though greened, are with restricted access (Zhu, 2008). Sky garden is a recent endeavour. Only a few private housing projects have been designed with this feature. Nonetheless, given the benefits discussed above, there is increasing interest, even in the public housing sector, to adopt this design to enhance liveability. But the Hong Kong Housing Authority has piloted different green design initiatives according to specific site conditions and constraints. For example, Eastern Harbour Crossing Phase 4 project was piloting a vertical green panel system in modular prefabricated external cladding, for use on vertical surfaces as well as roof areas. The modulated prefabricated panels enabled easy on-site installation and maintenance. In this project, green roofs were proposed for all roof areas with a minimum of 4 hours direct sunlight per day (including the roofs of lift towers and ground floor canopies). Horizontal trellises were provided on both sides of the footbridge roof top and double deck walkway to allow climbing plants, which will visually enhance the area as well as helping to reduce the heat island effect, and support insulation and energy efficiency (Hong Kong Housing Authority, 2007a). If successful, these green initiatives could set a milestone in the pursuit of environmentally sustainable public housing development.

4.4.5 Provision of Balconies A balcony is one of the green features that could be incorporated into the design of high-rise buildings. It offers several advantages over traditional window designs. First, it can increase extra living space for residents. In high-density areas, intensive development compresses the outdoor open space, and engenders small-sized flats. Also, there are often unavoidable ground noise and air pollution. Balconies help to mitigate these problems. Second, from an environmental standpoint, balconies can be a more sensible solution to traffic noise control without compromising views and urban image (Griffiths, 1999). It is especially relevant in high-density cities with high-rise buildings because the installation of noise barrier along the road for cutting down traffic noise to the upper building levels is often very expensive (Cheng, Ng, & Fung, 2000; Hothersall, Horoshenkov, & Mercy, 1996; Li, Lui, Lau, & Chan, 2003). Third, balconies can be used to increase the depth of the façade to buffer interior space and to reduce the solar heat gain. Balconies also provide an opportunity for landscaping. Further, plantings can assist with the buffering process, as

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they can catch the wind breeze to enhance natural ventilation (Yau, 2002). Fourth, balconies also provide semi-outdoor space for the natural drying of clothing and beddings. Without a balcony, occupants are forced to hang and dry their wet cloth inside the flat or in re-entrant space. This results in inconvenience and greater energy consumption if drying machine has to be used (Niu, 2004). Sanitary problems may also be posed if clothes are dried in narrow re-entrant space without direct sunlight. Thus, balconies do not only improve living quality, but also reduce energy use. In Hong Kong, for many years, balconies are not popular because they are included in the gross floor area calculation, thus their provision was at the expense of internal floor space. As an effort to enhance environmental sustainability, the government announced in 2001 that balconies smaller than 5 square meters will be excluded from gross floor area calculation (Building Department, Lands Department, & Planning Department, 2001). Though the exemption is granted with conditions (e.g. the balcony must be open at least on two sides), it has encouraged the market to explore green features as selling points, and has the impact of shaping consumers’ taste.

4.5 Conclusion This chapter has surveyed the sustainability advantages and disadvantages of residential high rises from the environmental perspective, and canvassed planning and design practices to improve their sustainability. Defining environmental sustainability of housing as the environmental impact of residential activities and the quality of the living environment for the inhabitants, this chapter found that most sustainability advantages of residential high rises pertain to reducing the environmental impacts, notably minimizing the use of natural land, building materials and transport energy. In contrast, the disadvantages are mainly the negative impacts on the quality of the living environment, particularly the problem of congestion and pollution. The urban context within which the high rises situate also affect the sustainability of these buildings, especially the planning policies for the provision of facilities and services to meet daily needs, such as transport and retail facilities. The five planning and design practices investigated and recommended in this chapter also focus on reducing environmental toll and improving liveability. They particularly aim to reduce the operation energy of high rises, especially in a more compact living environment. The energy-efficient envelope design, permeable spatial configurations, sky open space and balconies all have the effect of reducing the use of energy for ventilation, cooling, heating and lighting. Vertical organization of housing-related facilities within high rises is also regarded desirable for reducing transport energy consumption. The above designs also enhance liveability as more green and social space is provided within close proximity, while air and noise pollution are reduced, and more living space is provided. In many Asian cities, the provision of dwellings in the form of high rises is not a choice but the only solution to combat the deficiency in developable land and population growth. To build and

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operate more environmentally sustainable high rises is also not a choice but the only way to survive in the long term giving the limits of the earth. It is therefore imperative that more research be conducted to improve the environmental sustainability of residential and other types of high rises.

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Chapter 5

Garden and Ecology in the Sky Belinda Yuen

5.1 Introduction This chapter examines the greening and ecology promotion effort in high-rise housing environment. Urban greening encapsulates the strategies that protect and restore ecology within the urban area. Despite rapid urbanization, Singapore has emphasized tree-planting, landscaping and open space provision to maximize its environmental capital. The aim is to make Singapore a “better place to live”. Rather than treating the space between tall buildings as a loss of valuable building or for parking spaces, in Singapore, such space increasingly is being greened, and specifically created as part of the total living environment to give “heart” to the high-rise community. As described in Chapter 1, Singapore’s high-rise public housing is spatially clustered as new towns. Each new town is provided with considerable landscaping, including a connected framework of green open spaces, parks and gardens as the main structuring element of the community. Attention is on integrating the natural environment, albeit largely manmade, into the new community. The green spaces are an important part of the network of public spaces and ecology in the high-rise housing environment. Many scholars have discussed the importance of public space to urban quality of life (see, for example, Carr, Francis, Rivlin, & Stone, 1992; Low & Smith, 2006; Madanipour, 1996). As Carr et al. (1992, p. 3) assert public space is “the common grounds for play and relaxation”. It includes all publicly accessible (usually also publicly managed) spaces, which are designed primarily for public enjoyment. Common examples are the parks, gardens, and green open spaces. The multiple – aesthetic, cultural, environmental, psychological, recreation, restorative and social – benefits of the nature landscape of parks and green open spaces are well documented (see, for example, Kaplan & Kaplan, 1989; Swanwick, Dunnett, & Woolley, 2003; Low, Taplin, & Scheld, 2005). The convergence of the diverse benefits serves to emphasize the preservation, enhancement and creation of greenery in cities. As

B. Yuen (B) Department of Real Estate, National University of Singapore, Singapore e-mail: [email protected]

B. Yuen, A.G.O. Yeh (eds.), High-Rise Living in Asian Cities, C Springer Science+Business Media B.V. 2011 DOI 10.1007/978-90-481-9738-5_5, 

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Berg, Magilavy, and Zuckerman (1989) argue, urban greening is a manifestation of bioregionalism; it combines urbanism and nature to create healthy, civilising and enriching places to live. These spaces take on renewed pertinence in the increasingly urbanized society, particularly, high-rise living with its heightened verticality and high density. As Gobster and Barro (2000) note, urban people’s desire for interaction with nature is stronger than ever. In Singapore, as also the case in Hong Kong and many other cities, not all public housing residents will have the means and time to travel to distant places for leisure and recreation. The home and its immediate neighbourhood remain the space where residents relax and socialize, children do much of their playing, and elderly residents spend most of their time (Alexander, Ishikawa, & Silverstein, 1977; Forrest & Williams, 2001). These circumstances help reinforce the case for proximate green space provision in high-rise neighbourhood. Green open spaces are not a residual space but an integral part of any high-rise planning. While there is a rich literature on parks and public spaces, the topic of green open space in high-rise living remains barely explored. This chapter will examine the changing attitude to this space in Singapore’s high-rise living, and the emerging evidence on residents’ relationship with these green spaces. As Rogers (1999) remind in the review of British urbanism, Public spaces work best when they establish a direct relationship between the space and the people who live and work around it (p. 57).

As the number of tall housing expands under current sustainable development narrative, understanding that relationship will become ever more important. Skyrise greenery1 in Singapore’s latest 50-storey public housing development will be reviewed. The chapter will also discuss Singapore’s proactive approach to protecting the environment, and developing environmental sustainability in the design and construction of its high-rise public housing. Singapore’s first eco-precinct public housing development will be examined.

5.2 From Periphery to Centre-Stage Green open spaces in Singapore’s public housing have evolved from the once peripheral, leftover space to becoming an integral part of its new town planning (Yuen, 1996). During the early phase of public housing development, in the 1960s, attention is on development – building as many housing units as possible to meet the severe housing shortage (Wong & Yeh, 1985). Little consideration is given to the environment – the existing landscape and the location and quality of green open spaces. Green open spaces often are assigned sites that could not be used for housing. With the retreat of the housing shortage and increasing emphasis on quality of

1 In Singapore, skyrise greenery refers to the provision of rooftop gardens and the planting on parts of the building such as podium gardens, facade greenery and balcony planting.

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Fig. 5.1 Roof spaces are increasingly turned into gardens

life, more and more attention has been accorded to the provision of green open spaces, and designing with nature. These considerations are no longer marginal concerns but part of the increasing range of play and nature opportunities in the immediate home environment. Reflecting the wider national vision of a clean and green city, Singapore’s built environment increasingly is designed with nature to increase the diversity of land use, create the feel of a “city in a garden”, and stimulate a sense of place and community stake-holding. A green matrix of tree-lined streets, parks, green connectors and gardens on top of buildings provides nature opportunities in the rapid restructuring of the built environment (Fig. 5.1). In the process, green open space has become the most prevalent landscape feature in the public housing residential environment. The hierarchical provision of parks and gardens aside, the space between residential blocks2 is generally left green. As the Urban Redevelopment Authority (2002, p. 15) rationalizes, A liveable town is not merely measured by the significance and prominence of its buildings, but also the quality of the spaces that surround the buildings and arise out of the collage of structures.

spacing is computed by the formula: d = HL + 0.5HD + 0.1HU where d = minimum building spacing, HL = vertical overlap of the two buildings, HD = difference of ground levels of the two buildings, HU = difference of roof levels of the two buildings. See Wong and Yeh (1985) for detailed discussion. 2 Building

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These patternings reinforce other implementation of sustainable development advanced in its spatial plan (Keung, 1998). Under its long-term Concept Plan, spatial planning will capitalize on the country’s island character and existing tropical greenery by establishing an island-wide network of parks, gardens and connectors. As much as 24% of the country’s ultimate land area (or 177 km2 ) will remain green. Of this, 103 km2 will be natural woodlands (or 82% of current woodland areas). The Concept Plan envisages that the home and workplace environment will become “heavily decorated with natural tropical foliage”. The city will have more parks, and offer more leisure opportunities under its leisure plan, the Green and Blue Plan. The Green and Blue Plan, which derives its name from its focus on linking the system of open space (green) with the waterways (blue), proposes three main strategies to enhance the urban environment: • having more parks and gardens; • carefully tending the natural foliage; and • bringing the natural environment closer to the urban areas. The implementation of these strategies is effected through the development of six different types of open spaces: 1. natural open space (such as mangrove swamps, wooded areas and nature reserves which will be preserved); 2. major parks and gardens (such as regional parks); 3. sports and recreation grounds (including sports stadiums, golf courses and camping sites); 4. boundary separators (such as green buffers between new towns); 5. internal greenways and connectors (including proposed pedestrian malls that define and link neighbourhoods to town centres within new towns); and 6. other open space (including military training and agricultural areas). Rather than discrete and separate offerings, the six types of open spaces will be linked to one another, and to the coastal areas by a network of park connectors to realize the vision of Singapore as a garden city where accessibility to every part of the garden is ensured. The entire network of 360 km of park connectors is anticipated to complete in about 20–30 years’ time. Shifting the development of the built environment towards sustainability inevitably raises consideration about nature in the city. As alluded to earlier, the argument is for more, not less nature in cities. The motivation for urban greening is as much ideology as it is pragmatism. Urban trees contribute to the absorption of air pollution, and to the visual coherence of the regenerated city areas. As stated in Singapore’s national report to the United Nations, From the outset, Singapore has always recognised the role of plant cover in alleviating pollution, promoting rainfall and in improving the aesthetic quality of life, as well as the vital function of providing shade in our hot, sunny climate. (United Nations Conference on Environment and Development, 1992, p. 39)

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In a similar vein, Sherlock (1991) argues that greenery in urban areas is best provided by trees and shrubs in paving, be it in streets, in squares or in spaces between buildings. To improve the appearance and safety of the whole urban environment, Sherlock (1991) further advocates a minimum level of open space provision: every urban borough or district needs one substantial park with plenty of forest trees, and an area of grass large enough to survive universal use and the provision of formal recreational spaces in every neighbourhood. Jacobs (1961), however, discounts the idea of parks as lungs as science fiction. She argues that it has led to settlement dispersal, which in turn leads to greater use of cars and the production of more carbon monoxide in the atmosphere. The implication for urban form is clear. Integrated land use (and high-rise) support an urban compactness that could conserve resources. Urban development integrated with nature can not only save resources but also allow city dwellers to enjoy a more natural environment. This is crucial for high-rise development. High-rise when compared with low-rise single-family houses is often perceived with impediments to leisure and recreation opportunities. A common anxiety is over the lack of outdoor play space for children, the lack of opportunities for observing nature, and the stress of isolation (Conway & Adams, 1977; Jephcott & Robinson, 1971). In the extreme, such disaffection with high-rise living has proffered pressure for the cessation and demolition of high-rise housing (Costello, 2005; Helleman & Wassenberg, 2004).

5.3 Greening the Verticality In Singapore, within its basic new town planning prototype model, open space generally accounts for about 4% (approximately 26 ha) of new town land. Reflecting the British notion of park hierarchy, the distribution typically includes one town garden (5 or more hectares), several neighbourhood parks (1 per neighbourhood, each of 1–1.5 ha serving about 4,000–6,000 dwelling units), and precinct gardens (0.2 ha, 1 per 1,000–2,000 dwelling units). Each neighbourhood is self-sufficient in terms of open spaces and playgrounds. The parks and gardens have strong design features. The larger the space the wider is its range of facilities. Thus, the precinct garden, the smallest of these spaces, would typically appear as a landscaped green open space with seating, a children’s playground or a hard court for ball game (Fig. 5.2). The neighbourhood and town parks would have additional facilities such as pavilion, foot reflexology path, jogging track, cycling track and fitness station (Fig. 5.3). Provided with standardized recreational facilities like seats, swing and other play and recreation equipment, these spaces are basically what Low et al. (2005, p. 26) would term, “recreation facility parks” designed for vernacular recreation such as exercise, picnic, children’s play and arrival by walking. The guiding principle is to encourage access by proximity. In addition to the ground level recreation facilities, the apartment blocks are invested with a range of external public spaces to enhance residents’ accessibility to play spaces. Over the decades, there is not only more internal home space with

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Fig. 5.2 Children’s playground and/or hard court are common in precinct garden

larger and better-designed housing units but also external space. An example is the decision in the late 1960s to construct slab buildings with common corridor serving housing units on one side rather than on both sides, as was the case in earlier block design. This design change not only provided immediate gains in natural lighting

Fig. 5.3 A broader range of facilities in the neighbourhood park

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and ventilation but also created a space immediately outside the apartment unit front door for children’s play. With continued block design changes and the introduction of taller point-tower (25- and more storeys) blocks, some of these common spaces have expanded to become courtyard in the sky, creating semi-private lobbies, sheltered corridors and garden enclaves for residents. Since the 1990s, park connectors and vertical green open spaces – roof gardens – have been introduced to complement the ground level green spaces within the town-neighbourhood-precinct planning subdivisions. The modular prefabricated extensive green roof tray system is used in the roof garden to help ensure vegetation survival during dry season. Two systems are being tested in vertical greening, the transparent system, which uses steel rack and mesh and cables to create a porous look, and the opaque system, which uses a green wall system to give a planted look to the building surface. The vertical greening additions are aimed at bringing greenery and community spaces closer to individual homes as the buildings increase in height. The objective is to progress the whole town towards garden city living. Underpinning this is the goal to establish “home” places. As the Minister for National Development wrote, . . .we must remember that public housing is not just about good design. It is about building homes and communities. Building affordable homes that will meet the aspirations of families and building cohesive communities that will flourish with people from different backgrounds coming together in one place, to live, work and play; a place that they are all proud to call home. (Urban Redevelopment Authority, 2002, p. 6)

In the Duxton Plain public housing redevelopment, 1848 new homes will be built at a plot ratio of 8.4 and up to 50 storeys.3 This marks the tallest public housing in Singapore. The brief is to provide fresh, innovative and new ideas on how high-rise, high-density public housing can create an attractive and environmentally conscious living environment. The winning design, selected from more than 200 entries from around the world, includes a continuity of vertical greenery that provides the seven tower blocks with view, air and light flow, and sky park connection at the 26th and 50th storeys. The sky parks, located on the 26th storey and roof level, are designed for openness, panoramic view of the city and safety with a landscape moat and glass windbreak. Two high-speed lifts and seven standard lifts connect the sky parks to residents and ground level. At ground level, existing greenery will be preserved and landscaped into a historical garden – central plaza for the residents, and as a landmark to the development. In addition, new landscape design will heighten human scale, and offer varying degrees of privacy and enclosure, depending on the viewing axis, height and density of the trees. The design is under construction, expected to complete by 2010. To what extent is the green spaces being used? While there is extensive documentation on Singapore’s high-rise public housing programme (Wong & Yeh, 1985;

3 The redevelopment of Duxton Plain site is the subject of an international competition in 2002. The site is 2.5 ha with 334 flats in 2 slab blocks built in 1963. See Urban Redevelopment Authority, 2002, for more details.

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Yuen, Teo, & Ooi, 1999), there are fewer specific elaborations on its green spaces. From the authority or provider’s perspective, the green spaces and their facilities are planned to meet “the needs of residents”, and “play an important role in promoting social interactions and forging community bonds among residents” (Housing and Development Board, 2003a, p. 59). Against the basic assertion that public space exists to serve the needs of people, such space is continually redefined, and given purpose through usage. At the nexus remains the investigative concern with people – “how the particular setting does or might facilitate particular kinds of behavior which are hopefully or necessarily to be carried out in that setting” (Proshansky, Ittelson, & Rivlin, 1976, p. 435). For the purpose of clarity of exposition, the analysis draws on Madanipour (1996) social space dimensions of access, agency (ownership), and interest (benefit) as the framework for discussion. This conceptualisation reflects one of the key themes of modernist planning (Colquhoun, 1989; Lefebvre, 1991). Access, as Lynch (1981) defines it, is the ability to reach other persons, activities or places. In the study of public spaces, this access, as Carr et al. (1992) argue, may be visual, symbolic or physical, affecting people’s entry into, and their use of the space. As public spaces in public housing towns, the green spaces in Singapore’s high-rise – precinct gardens, neighbourhood and town parks – are open to all. There are at present no gates, fences or security measures to prevent anyone, resident or outsider, from entering the public new town, neighbourhoods, precincts, blocks and public spaces. At night, the public spaces are well lighted to enhance safety and security.4 By design, the local precinct gardens are readily accessible on foot, and visually oriented in good view of dwellings. Their landscape and provision clearly define these public spaces as parks and gardens for recreation use. Accordingly, ball games, for example, are not permitted in the void deck, access corridors or lift lobbies of the apartment block,5 but in the green open spaces, especially where the appropriate play court/field is provided. The operational framework of facility provision, rules, and regulations set the limits of public life, and behavioural cues for the use/non-use of public spaces in the new town. According to the latest Sample Household Survey 2003,6 about 18% of public housing residents had used the park, fitness corner, jogging track and children’s playground on a weekly basis, while 82% had used these facilities on less than weekly basis. Compared to 5 years ago, the weekly usage of fitness corner/jogging track had increased (10% of residents reported this use in 1998), but the weekly usage level of children’s playground and park indicated a decline (23% of residents in 1998). Although no reason was offered for the trend, consideration of the wider 4 Residents, whether renters or owners pay a monthly service and conservancy charge (amount vary according to flat size) towards the town’s public cleansing and maintenance. 5 The void deck is the ground or 1st storey of the block that is deliberately left vacant – void—as a sheltered space for the organization of big family events such as funeral wakes and weddings. 6 Conducted at intervals of about 5 years, this survey on residents living in public flats yields information on their demographic profile and adaptation to high-rise living.

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socio-demographic development suggests the probable influence of more people embracing sports as a lifestyle (sport participation of the population as a whole has increased by approximately 47% over the same period under the national sports for all programme), and declining national birth rate7 . Examination of the findings in respect of household’s family life cycle indicates families with children as the major user of children’s playground: 45% were families with young children (up to 12 years old), 17% were families with teenaged children (below 21 years old), 20% were families with married children/grandchildren (Housing and Development Board, 2003a). The children’s playground in the precinct garden is generally designed for young children aged 2–8 years old while the hard court is for older children. An average of 350 users per day has been recorded in the precinct garden, and the majority, 43% of observed activities are play-related (Dao & Yuen, 2005). The favoured time of visit is generally either in the morning (before 9 a.m.) or late afternoon/evening, after 4 p.m.; fewer residents had visited the public space during mid-day. The average duration of on-site usage has been generally around 20–30 min. On-site observation also pointed to residents seeking out shaded places during the day, and using the not so shaded outdoor spaces when the weather is much cooler. This is understandable given Singapore’s equatorial climate with day temperatures (Celsius) in the mid-30s (Singapore is located 1◦ north of the equator). As Carmona, Heath, and Tiesdell (2003) argue elsewhere, climate – the level of sunshine, humidity, rain, etc – can be a major factor influencing usage. In particular, “comfort is a prerequisite of successful public spaces” (Carmona et al., 2003, p. 165), and might not be compromised. Notwithstanding that the usage may be a reflection of site provision – the availability of playground – the data reinforces the relevance of open access to play provision in high-rise. The basic premise is that children, especially young children, need proximate outdoor play spaces within home range for healthy growth (Conway & Adams, 1977; Hart, 1979; Moore, 1990). Compared to playground, the neighbourhood park and their broader range of facilities, including fitness corner/jogging track tend to have a wider appeal, attracting usage from every life cycle stage of the households. Among the many facilities of the new towns, commercial facilities like the market/supermarket and shop are the better-used provision with over 80% of residents visiting these on a weekly basis. Even though parks and gardens may not have been the most used facility, the majority, 93% of resident households have continued to express high overall satisfaction with the facilities (Housing and Development Board, 2003a). Interestingly, satisfaction level appeared generally higher among households living in smaller flats who incidentally were also families with lower income. As an amorphous space between high-rise buildings, the ubiquitous green open space is a neutral ground where residents can come and go as they please throughout 7 During the 2006 National Day speech, the Prime Minister has announced a number of strategies including immigration as the fillip to the continuing decline in birth rate, which has remained below replacement level for the 28th straight year. See http://www.workpermit.com/news/2006_08_22/ global/singapore_needs_immigrants.htm accessed on 13 Dec 2006 4:54 pm.

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the day. Easy accessibility and regular usage are investing this nondescript space with ownership, affinity and happening for certain groups in the community. The precinct garden with its children’s playground, for example, offers a familiar place where children and their caregivers would readily recognise and go in their daily lives. Majority of the caregivers are women – mothers or maids – watching over their children at play. Their access to the playground opens opportunity for social interaction with other caregivers, and an escape from the house and domestic life. Empirical research from other cities has often found that parks are places for social interaction, escape and diversion from urban living (Kaplan & Kaplan, 1989; Low et al., 2005). Karp, Stone, and Yoels (1991, p. 153) have taken this usage a stage further by reflecting the dominance of women in park as the “gendered nature of urban space”. By contrast, in the hard courts designed for ball games, the dominant users are almost exclusively male, mostly teenagers or young adults who have gone to the space on their own or with friends and siblings (Dao & Yuen, 2005). Comparative studies of residential satisfaction among American suburban teenagers and those living at higher density with easy access to shops, public transport, etc. in Sweden indicate that the former group is more often bored and engage in vandalism than the latter group (Cooper Marcus & Sarkkissian, 1986). By implication, teenagers in high-rise housing are more likely to find others of the same age group living within walking distance, and have access to common shared facilities out of sight of the home, yet not far away. Just as the precinct garden emerges as a core setting of children and teenagers, adult and elderly residents appear the more frequent user of neighbourhood parks, and the seating in the precinct spaces. It is not uncommon to find the elderly, singly or in groups, sitting and relaxing in the climatically protected void deck on a daily basis. Their presence has prompted the authority and local community groups to provide elderly-related leisure facility such as chess play sets, elderly fitness equipment, and sometimes even an old piano to create senior citizens’ corner. In consequence, the void deck is not just for pedestrian movement (to get in and out of the apartment block), but joins the green open space to contribute to everyday social life. It is a place where children play when they cannot get to outdoor play areas because of rain (they are, however, not allowed to kick ball in the void deck), the elderly meet and talk to one another, relax or just people watch. Even though often manmade, and at times minimalist in design, the residents would point to the green spaces in public housing as a near-home place that they could go for a bit of nature in the immediate home range. The central narrative among residents is that these parks and playgrounds are a convenient commonplace for their respective daily routine activities. Some would seek specific activities (such as to exercise or to sit, relax and be with nature in the garden) hoping or certain that particular provision (for example, greenery, exercise equipment or seats) would be available in the place. Others perceive the garden as a convenient meeting place in the neighbourhood where they could meet their neighbours, hold block parties, and promote neighbourly activities and interaction. As usage develops, these spaces become increasingly “claimed”, and invested with social relations and informal

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public life. According to the Housing and Development Board (2003b), residents at neighbourhood parks and playgrounds generally record knowing many more neighbours than those who reportedly meet each other along access corridors and staircases. The usage of green open space grounds support for their provision in high-rise housing. From an environmental perspective, the benefit includes clean urban air and reducing the urban island heat effect, which is well documented (Chen & Wong, 2006; Wong & Chen, 2005). It offers the high-rise a “softer and greener” environment. From a social perspective, Alexander et al. (1977) have long postulated that people will visit urban greenery on a regular basis if it is within 3–5 min walk of their home or workplace. An attractive green environment offers many opportunities for urban social life. Others have acknowledged with empirical data that most urban residents visit parks and gardens for a range of reasons (Kaplan & Kaplan, 1989; Low et al., 2005). The interest might have been to connect with nature, provide pleasure, aesthetic satisfaction, social interaction, rejuvenation, and better quality of life through exposure, active or otherwise, to fresh air, sunlight, and open space. In many ways, the preference for green open space is the option to have opportunity to do all of these activities and more. In a similar vein, Oldenburg (1997, p. 16) has argued the importance of providing urban residents with “third places” that “host the regular, voluntary, informal, and happily anticipated gatherings of individuals beyond the realms of home and work”. Cast against the multiple functions of green space, the emerging sense is that it would appear counter-productive not to provide these spaces on an everyday basis, especially in the high-rise residential environment. Almost as a reminder, Singapore residents when speaking of their concerns with high-rise living seem to worry more over a lack of neighbourhood facilities than they would over lift breakdown, crime in the lift, and collapse of the buildings (Yuen et al., 2006).

5.4 Ecological Design Singapore increasingly has turned towards environmental sustainable development in its high-rise public housing programme. At the macro level, public housing new town with its mixed land use, cradle to grave facilities and high density is designed to minimise the need for travel. The new town is designed for the pedestrian and transit as well as the car, facilitating easy movement through all parts of the town by foot, bicycle, public transit and bus. Pedestrian comfort is enhanced with the provision of sheltered walkways, traffic calming within the precinct roads and car parking lots increasingly placed in multi-storey car parks, providing an attractive, safe and inviting public realm. As mentioned, rather than “demolish and build”, the existing landform is increasingly recognised and integrated into the new town development to celebrate local history and ecology. As set out in the Concept Plan 2001, the proposal is for strengthening identity in new towns with the participation and input of the community, including “existing features that are unique, significant landmarks and natural elements as part of new developments”.

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At the micro level, the apartment blocks and their flats are designed to encourage natural lighting and cross ventilation so as to reduce energy need. Building facades are generally oriented to face north-south, minimising the east-west sun exposure. Fenestration, secondary roofing and wall design including gable end cavity wall, ventilated and cool wall as well as zero energy and low-energy systems further improve energy and comfort level. Water conservation and recycling is built into its water sensitive urban design, which encompasses all aspects of an integrated urban water cycle management. Recycled material and equipment are part of its alternative construction resource. Many of its playgrounds, street furniture and rubbish bins provide examples of recycled equipment. Public housing is increasingly built with the use of prefabrication technology that has not only improved the speed of construction but also optimised resource use, reducing unnecessary wastage, noise and air pollution on site. More and more, public housing is designed with nature, incorporating greenery and green technologies for optimal usage of energy and water. The environment is seen as a basic part of development that enhances the ecological agenda and quality of life. The “prime site” of the environment is the eco-precinct demonstration project, introduced in 2007 and expected to complete in 2010–2011. The eco-precinct to be developed at Treetops, Punggol new town will have 712 flats in seven 16-storey blocks. Residents will be served by the public bus, rail and light rail transport network, providing easy access within the town and to the rest of the city. The development will incorporate a range of green building technologies and innovations for effective energy, water and waste management, including green balconies and roofs, solar panels to generate lighting for common areas (this will save 80% of energy used), centralised recycling refuse chute and rainwater collection system. Green linkways – Green Path – and extensive greening on the facade and roof of buildings – eco-deck – will help to relieve urban heat island effect (anticipated to reduce surrounding temperature by as much as 4◦ C), and provide shaded walkway and spaces for the social interaction of residents. Greenery provision is anticipated to be greater than 4; for most existing public housing greenery provision ranges from 2.8 to 4. The eco-precinct will cost 5–8% more to build than conventional public housing. However, the contribution to the environment cannot be neglected. Studies have shown that energy-efficient green buildings can be cost-effective in the long-term; energy consumption can be reduced by as much as 35%. The eco-precinct at Treetops, Punggol new town has been accorded the Platinum Green Mark Award (top award), which is a scheme launched by Singapore Building and Construction Authority in 2005 to promote sustainability in the built environment. The Green Mark Scheme is a green building rating system that evaluates a building for its environmental impact and performance along five key dimensions: energy efficiency, water efficiency, site/project development and management, good indoor environmental quality and environmental protection, and innovation. Green building is part of a wider national effort. Under its Green Building Master Plan, the Building and Construction Authority is actively promoting research and development in green buildings through its S$20 million Green Mark Incentive Scheme. The incentive is scaled on the basis of Gold (S$3 per m2 gross floor area),

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Gold Plus (S$5 per m2 gross floor area) or Platinum Green Mark Award (S$6 per m2 gross floor area), up to S$3 million in cash. Secondly, the industry may apply for funding under the Ministry of National Development S$50 million research fund to intensify research and development in green building technologies and energy efficiency, and thereby making the mass application of green building technology more viable and cost-effective. The eco-precinct marks a new phase of high-rise public housing development in Singapore. The new generation of high-rise public housing is anticipated to explore further concepts of sustainable community such as housing-in-a-park, sky gardens and community gardens.

5.5 Conclusion This chapter has argued that green open space is important to high-rise living. Equally important is the need to reinforce environmentally sustainability in highrise building development. Its compact form offers opportunity to minimise building footprint, maximise mixed use, and incorporate green technologies and innovations. In the face of climate change, designing towards environmental sustainability is no longer an option. It is a must-do for cities. Many urban neighbourhoods need more green space. A major criticism of high-rise built form is often its homogeneous stratification of floors – vertical stacking, leading to design standardisation and monotony. The homogeneity of spaces, however, could be softened and made aesthetically beautiful by a matrix of greenery, vertically considered. Greenery in high-rise is not an ornamental, marginal provision but a functional, integral component of high-rise living. Green linkages and spaces provide for “place making” and public spaces in the sky, re-creating ground conditions – the continuity of spaces and circulation, the provision of immediate access to nature and open spaces, etc – in the vertical city. The emerging evidence is that high-rise residents use (even though not all of the time) and appreciate this public space in their immediate residential area. Indication is that these green spaces create various opportunities for the high-rise community. Even though by themselves the opportunities and activities may be everyday commonplace happenings, they contribute to neighbourhood amenity and the spatial realities that ground support for public space provision in the high-rise residential environment. As this chapter demonstrates, the green space offers convenient familiar settings for relaxation, discovery and social interaction with peers, neighbours, and family. Children can use the space for play; teenagers for active sports, to meet friends or hang out, etc, a few minutes away from their homes. Adult residents draw on the space for neighbourly interaction, daily exercise routines, relaxation, peace and private conversation, and an alternative to being in the apartment. In other words, the community creatively uses the green space for a variety of day-to-day purposes. To neglect, or worse, close off such provision is to paralyze the everyday life activities of the residents, and diminish the high-rise living experience. This perspective pivots us towards understanding and sanctifying green space from that of the users: the residents and the ways in which they discover, consume, and

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experience the space. As Jayne (2006) reminds, “The city is produced and consumed through commonplace and everyday spaces and activities . . . in parks, the street, shopping centres, and so on.” (p159) They represent a fundamental asset in the “total living environment” that has potential to address social needs, support community interaction and progress environmental sustainability.

References Alexander, C., Ishikawa, S., & Silverstein, M. (1977). A pattern language. New York: Oxford University Press. Berg, P., Magilavy, B., & Zuckerman, S. (1989). A green city program for San Francisco bay area cities and towns. San Francisco: Planet/Drum Books. Carmona, M., Heath, T., Oc, T., & Tiesdell, S. (2003). Public places-urban spaces: the dimensions of urban design. Oxford: Architectural Press. Carr, S., Francis, M., Rivlin, L. G., & Stone, A. M. (1992). Public space. New York: Cambridge University Press. Chen, Y., & Wong, N. H. (2006). Thermal benefits of city parks. Energy and Building, 38, 105–120. Colquhoun, A. (1989). Modernity and the classical tradition: architectural essays 1980–1987. Cambridge: MIT Press. Conway, J., & Adams, B. (1977). The social effects of living off the ground. Habitat International, 2(5), 595–614. Cooper Marcus, C., & Sarkissian, W. (1986). Housing as if people mattered: Site design guidelines for medium-density family housing. Berkeley, CA: University of California Press. Costello, L. (2005). From prisons to penthouses: The changing images of high-rise living in Melbourne. Housing Studies, 20(1), 49–62. Dao, T. C., & Yuen, B. (2005, April 11–13). Constituting the use in the making of local spaces. Proceedings, conference on Sustainable Building, South-East Asia (SB04 series), Kuala Lumpur, Malaysia. Forrest, R., & Williams, P. (2001). Housing in the twentieth century. In R. Paddison (Ed.), Handbook of urban studies (pp. 88–101). London: Sage. Gobster, P. H., & Barro, S. C. (2000). Negotiating nature: Making restoration happen in an urban park context. In P. H. Gobster & R. B. Hull (Eds.), Restoring nature: Perspectives from the social sciences and humanities (pp. 185–207). Washington, DC: Island Press. Hart, R. (1979). Children’s experience of place. New York: Irvington. Helleman, G., & Wassenberg, F. (2004). The renewal of what was tomorrow’s idealistic city: Amsterdam’s Bijlmermeer high-rise. Cities, 21(1), 3–17. Housing and Development Board. (2003a). Public housing in Singapore: Residents’ profile and physical aspects. Housing and Development Board Sample Household Survey, Housing and Development Board, Singapore. Housing and Development Board. (2003b). Public housing in Singapore: Social aspects and the elderly. Housing and Development Board Sample Household Survey. Housing and Development Board, Singapore. Jacobs, J. (1961). The death and life of great American cities. New York: Vintage. Jayne, M. (2006). Cities and consumption. London: Routledge. Jephcott, P., & Robinson, H. (1971). Homes in high flats: Some of the human problems involved in multi-storey housing. Edinburgh: Oliver and Boyd. Kaplan, R., & Kaplan, S. (1989). The experience of nature. Cambridge, MA: Cambridge University Press. Karp, D., Stone, G., & Yoels, W. (1991). Being urban: A sociology of city life. New York: Praeger. Keung, J. (1998). Planning for sustainable urban development: The Singapore approach. In B. Yuen (Ed.), Planning Singapore: From plan to implementation. Singapore: Singapore Institute of Planners.

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Lefebvre, H. (1991). The production of space. Oxford: Blackwell. Low, S., & Smith, N. (2006). The politics of public space. New York: Routledge. Low, S., Taplin, D., & Scheld, S. (2005). Rethinking urban parks. Austin: University of Texas Press. Lynch, K. (1981). Good city form. Cambridge: MIT Press. Madanipour, A. (1996). Design of urban space: An inquiry into a socio-spatial process. New York: Wiley. Moore, R. (1990). Childhood’s domain: Play and place in child development. Berkeley, CA: MIG Communications. Oldenburg, R. (1997). The great good places. New York: Marlowe and Co. Proshansky, H. M., Ittelson, W. H., & Rivlin, L. G. (1976). Environmental psychology: People and their physical settings. New York: Holt, Rinehart and Winston. Rogers, R. (1999). Urban task force, towards an urban renaissance: Final report of the urban task force. London: Department of Environment, Transport and the Regions. Sherlock, H. (1991). Cities are good for us: The case for high densities, friendly streets, local shops and public transport. London: Paladin. Swanwick, C., Dunnett, N., & Woolley, H. (2003). Nature, role and value of green space in towns and cities: An overview. Building and Environment, 29(2), 94–106. United Nations Conference on Environment and Development (UNCED). (1992). Singapore’s national report for the 1992 UN Conference on Environment and Development. Singapore: Inter-Ministry Committee for the UNCED Preparatory Committee. Urban Redevelopment Authority. (2002). Duxton plain public housing. Singapore: Urban Redevelopment Authority. Wong, N. H., & Chen, Y. (2005). Study of green areas and urban heat island in a tropical city. Habitat International, 29, 547–558. Wong, A., & Yeh, S. H. K. (1985). Housing a nation. Singapore: Housing and Development Board. Yuen, B. (1996). Creating the garden city: The Singapore experience. Urban Studies, 33(1), 955– 970. Yuen, B., Teo, H. P., & Ooi, G. L. (1999). Singapore housing: An annotated bibliography. Singapore: National University of Singapore. Yuen, B., Yeh, A., Appold, S. J., Earl, G., Ting, J., & Kwee, L. K. (2006). High-rise living in Singapore public housing. Urban Studies, 43(3), 583–600.

Chapter 6

Legislation and Safety of Tall Residential Buildings Wah Sang Wong

6.1 Introduction Vitruvius, a Roman architect in the first century BC considered as the first architect, has defined three interrelated qualities for the completeness of architecture in his book, De Architecture: firmitas, utilitas and venusta. “Firmitas” means strength and stability, which is the technical basis. “Utilitas” means utility and usefulness, which is the functional aspect. “Venustas” means attractiveness and liveliness, which is an abstract, spiritual aspect. Together, these qualities mean durability, convenience and beauty, laid out in that order (Vitruvius, 1960). In other words, it is the actual building with “firmitas” as the basis to support “utilitas” that gives rise to “venustas”. The aspect of safety in tall buildings can also be addressed in a similar manner. Consideration of safety in the physical establishment of a building will create “firmitas”, which allows activities to be carried out under conditions of safety. Together with the phenomenon of “utilitas” the result is “venustas”, supporting positive feelings of safety. Hence, safety can be seen as a persistent inseparable issue, no matter how we look at buildings. The sequence of Vitruvius’ terms, however, is changed following Sir Henry Wotton’s translation in the seventeenth century to form a new sequence of “commodity, firmness and delight”. Here, “commodity” takes the lead, and with “firmness”, they form the essential logical prerequisites of architectural beauty (Wotton, 1624). This can be seen as taking the sequence from the viewpoint of design; hence function is used to determine form and subsequently aesthetics. Applied to the subject of safety, it can be said that the concern of safety as a function is used to design form that generates the aesthetical effect of safety. To a large measure, this is the thinking when modernism entered architecture in the last century. The ideology of modernism in architecture (1920–1960) can be represented by the idiom of “Form follows function” (Nerdinger, 1985). The modernists believed in a functional approach to determine form. Architectural design is perceived as a

W.S. Wong (B) Department of Architecture, The University of Hong Kong, Pokfulam, Hong Kong e-mail: [email protected]

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process to transform functions into physical building forms. In consequence, buildings are efficiently designed and constructed with developable space. Combined with efficiency, functions are further pursued in a highly commercialized environment with the result that buildings are looked at as businesses. Developable space becomes a commodity. Economic value is assigned to different aspects of a building. As economy takes priority in modern cities, “form follows finance” becomes another common idiom of architectural design (Willis, 1995). In recent years, disastrous global events like Sep 11 2001 terrorists’ destruction of tall buildings in New York, and the spread of SARS in 2003 in densely populated Asian cities have triggered concern and closer scrutiny of building safety in the urban environment. Will it become a case of “form follows safety”? To properly administer safety in a fair and acceptable manner, legislation is a formal way of upholding safety standards in the modern residential environment. Legislation through the building code becomes the common means of control. In an environment of high density, private residential spaces are particularly vulnerable under real estate economy. The influence of financial considerations has to be limited, otherwise there is only influence based on economic power and no control for public concern. This chapter will discuss the urban background of high-rise buildings, the issue of safety in modern habitat, the means of legislative control, the key variables of the building code. It will also review the development of building legislation in Hong Kong, the effectiveness of the control system, and discuss their contribution to sustainability and the development of the three mentioned interrelated qualities of architecture.

6.2 From High-Density to High-Rise The development of high-rise buildings can be traced to the effect of urbanization. In China, the urbanization process, which started from the 1978 economic reform, has brought one-third of China’s 1.3 billion people to live in cities, and its rate of urbanization will allow one-half of that total population (forecasted as 1.45 billion) to be urbanized by 2020. High-rise buildings have become a norm for residential buildings, and the continuous demand to produce high-rise buildings in cities is forecasted (Dou, 2003; Edwards & Turrent, 2000). In the case of Hong Kong, the rate of change from a fishing village at the time of British colonization in 1841 with a population of a few thousands to its present metropolis with almost 7 million people is indeed fast. The resultant landscape is a high-density urban environment with high-rise buildings. Due to its hilly topography, the built-up area is highly concentrated on the relatively flat land as early as the late nineteenth century. This can be seen from the close packing of 4- to 5-storey tenement houses at that time (Walker & Rowlinson, 1990). With the advancement of building technology, Hong Kong has become a situation of both high density and high-rise (Fig. 6.1). With the prevalence of high density, hazards of fire and health have been the issues for control in achieving an environment of safety. There are many cases to

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Fig. 6.1 The high-rise and high density phenomenon of Hong Kong

give alarm for concern of a safer and healthier environment. For example, in 1878, a huge fire broke out in Central, burning down 368 houses. In 1918, a great fire at Happy Valley race course killed 600 people. In 1937, cholera killed more than 1,000 people. In 1953, a fire at Shek Kip Mei left 60,000 people homeless. The recent spread of SARS in 2003 killing hundreds of people in the urban environment is alarming. Hence, the control of safety is fundamental for the development of a high-density city, and the legislation relating to density and safety is a key issue. From the planning point of view, the density of development is related to specific usage and number of persons, which affect the provision of infrastructure and amenities for the neighbourhood. The usage of the development and the number of persons are quantified as the amount of Developable Space. In other words, the space bounded by the site that is supported by a building structure to form physically contained functional space allowing human activities or building servicing. It can be measured in volume or area, depending on the system of control and calculation. In the Hong Kong Buildings Ordinance, developable space is controlled by the two clauses on “plot ratio” and “site coverage” in the Building (Planning) Regulations (Buildings Department, 1998). These determine generally the maximum development. Both means of control involve the term “gross floor area”. This is defined in the Building (Planning) Regulations (1998) as “the area contained within the external walls of the building measured at each floor level (including any floor below the level of the ground), together with the area of each balcony in the building, which shall be calculated from the overall dimensions of the balcony (including the thickness of the sides thereof), and the thickness of the external walls of the building.”

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Fig. 6.2 Typical plan of a common cruciform shaped plan in the Hong Kong residential buildings for efficiency

Through such definition, public common spaces such as elevator shafts, lobbies and staircases are minimized to achieve the maximum saleable floor area in residential buildings. Hence, the resultant typology of these high-rise residential buildings is a uniform eight-unit with central core plan with minimum consideration on other design aspects such as health or safety (Wong, 1999) (Fig. 6.2).

6.3 Issue of Safety Under the Legislation for the Habitat As discussed in Section 5.2, the issue of safety is a basic concern in the making of legislation for the control of residential buildings in Asian cities. Yet, there are subtle differences and emphasis in different cities to reflect the cultural variation or development standard. In China where a lot of urban development is in progress,

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Fig. 6.3 Residential buildings in Shenzhen, mainland China

the Department of Construction ( ) under the Evaluation Standard ( ) defines the function of residential buildings as to satisfy the residents with regard to the accumulation of fundamental issues of usability, safety and health, etc (CCIP, 1997) (Fig. 6.3). ) is denoted as one of the fundamental issues. Indeed, safety Safety ( is assessed as 10% of the weightage in China’s Evaluation Standard, and is subcategorised as safety measures and structural safety, which are further established with weighting of 40 and 60% respectively (Table 6.1). For safety measures, these are specifically stated as fire safety, theft safety, safety to prevent falling safety to prevent electric shock, etc. Rating is given to encourage good practice and innovation. On the other hand, structural safety is defined as conformity to structural requirement. This can be seen as technically clear for the definition of safety issues in quantitative terms in the current construction of residential buildings in China. In the developed Asian countries such as Japan, the purpose of the Building Standard Law is precise with its statement by the Ministry of Construction as “to safeguard the life, health, and property of people by providing minimum standards concerning the site, structure, equipment, and use of buildings, and thereby to contribute to the furtherance of the public welfare”. No matter how advanced the technology, protection for people is well announced. Through the coverage of the Japanese law to include “general provisions”, “site, structure and building equipment of buildings” and “site, structure and building equipment of buildings within city planning areas”, etc, the consideration of safety for both people and property is well stated in the purpose, which the interpretations and applications are built upon and stipulated into the individual items of the law articles (Fig. 6.4).

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W.S. Wong Table 6.1 Weighting for evaluation standard in the design of residential buildings in China Function aspects Primary criteria 1

Spatial planning and layout

2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18

Plan data

Kitchen and bathroom Habitability

Safety Architectural design

Weighting Secondary criteria Integrated effect of spatial planning Average room numbers Orientation and size of bedrooms and living rooms Furniture layout Storage facilities Average construction area of unit Efficiency of usable area Average frontage of unit Kitchen layout Bathroom layout Lighting Ventilation Heat insulation Acoustical insulation Safety measures Structural safety Facade effect Interior effect

Primary weighting (%) 35

Weighting (%) 9

9 8

20

5 4 8

15

7 5 8

10

10 10

7 3 2–3 2–3 2 4 6 6 4

In a city with a strong government such as Singapore, control is provided in the legislation administered by the Building and Construction Authority (Building Control Act, 1999). It looks at such legislative control from the boarder perspective of urban design and incorporates “buildings, structures and infrastructure” as the “built environment” to “provide the setting for the community’s activities”. “We shape a safe, high quality, sustainable and friendly built environment” is the Building and Construction Authority statement of mission. The Singapore Building and Construction Authority (BCA) focuses on four key areas: “safety, quality, sustainability and user-friendliness” to achieve the vision to have “the best built environment for Singapore, our distinctive global city”. These four areas are interrelated. The following strategic thrusts are formulated to achieve the vision: 1. We (BCA) aim to be a caring and progressive organization that values its people, the innovative spirit, integrity, and service excellence 2. We ensure high safety standards and promote quality excellence in the built environment 3. We champion barrier-free accessibility and sustainability of the built environment

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Fig. 6.4 Residential buildings in Fukuoka, Japan

4. We lead and transform the building and construction industry by: a. b. c. d.

Enhancing skills and professionalism Improving design and construction capabilities Developing niche expertise Promoting export of construction related services

5. We forge effective partnerships with the stakeholders and the community to achieve our vision. This can be seen as a holistic approach with safety issues relating to the other disciplines of management, design, technology and community. The actual provisions are formulated in the Building Control Act (Chapter 29), (Building Control Act, 1999) (Fig. 6.5). Clear legislation for safety is also seen in the highly dense city of Hong Kong. The authority of building control in Hong Kong is the Buildings Department with its director acting as the Building Authority. Its vision is “to make the built environment safe and healthy for our community” while the mission statement is “to set and enforce safety, health and environmental standards for private buildings”. The issue of safety is thus clearly stated. This is consolidated in the Building Ordinance with its long title “to provide for the planning, design and construction of buildings and associated works; to make provision for the rendering safe of dangerous buildings and land; and to make provision for matters connected therewith”. This Ordinance is further supported by Building Regulations in various fields and codes of practices.

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Fig. 6.5 Residential buildings in Singapore

For example, the Fire Safety (Buildings) Ordinance enacted in 2007 is a supporting legislation regarding building safety in residential buildings (Buildings Department, 2007a). Its long title states that it is “An Ordinance to provide for fire safety improvements to be made to certain composite buildings and domestic buildings and to provide for related matters”. Hence, composite buildings mean a site with buildings used for both domestic (residential) and non-domestic purposes (Fig. 6.6). Going through the safety issues in various legislations, it can be understood that in China, safety is placed with quantitative control to measure and allow flexibility in various standards of residential buildings. In Singapore, the safety factor is more integrated with the environment and society. In Hong Kong, safety, health and environment are looked upon as joint measures to make a liveable habitat (Buildings Department, 1999). In Japan, the law safeguards people’s life, health and property. The indication is a progression towards urbanization or development where the basis of legislation moves from building standards and control to include a boarder view of the environment for the community, serving people is the ultimate goal.

6.4 Aspects of Legislative Control The principle of development control through three levels of scale based on land matters, planning issues and building code is widely adopted. However, such landuse planning and zoning methods usually result in a functionalist vision in planning. One of the outcomes of such a planning approach is the International Style where tradition and regionalism can be lost (Kurokawa, 1988). Kurokawa (1988) has

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Fig. 6.6 Residential buildings in Hong Kong

argued that the functionalist trend for rational design should be revised in the modern perspective to explore issues relating to the profundities of the human spirit, which is “rich with ambiguities and harmoniously balanced”. The focus on safety is often not apparent in the lease condition or zoning requirement, which reflects respectively the legislative control on land matters and planning issues. At the planning level, what is usually seen is the allocation of open spaces in the form of parks or plazas to lower the sense of high density in the urban fabric. On a broad scale, the phenomenon of urban renewal can be seen as a planning exercise to improve the safety and health conditions of an existing city. In Singapore, the Housing and Development Board was set up in 1960 under the Housing and Development Act to clear the housing deficiency and provide housing for the population. In the process, the housing strategy had facilitated the urban renewal of the densely populated city area (Dale, 1999). A similar situation is found in Hong Kong when the Housing Authority was set up to respond to a housing crisis where 60,000 people were left homeless after a fire broke out in Shek Kip Mei squatter settlement

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on Christmas night of 1953 (Yeung & Wong, 2003). It was the urgent demand for housing and safety that gave impetus to these government housing organisations, and through which work, urban renewal is a continuous process to upgrade the standard of health and safety. To explicate the three levels of controls in Hong Kong, we turn to the work of several scholars. Lai (1997) has stated that the lease document in Hong Kong being the land contract would allow for maximum development. The building has to be completed within a time period to avoid complete waste of land. Re-entering land by government is also possible for a “public purpose” before the expiry of the lease. When the tenant causes nuisance such as rendering the building unsafe to waste the land, the government can also re-enter the land. In addition, Nissim (1998) has highlighted the main purpose of the Building Covenant laid out in lease conditions of Hong Kong as to ensure that the site would be developed with an acceptable amount of floor space within a reasonable period of time. Master Layout Plans are prepared for large-scale developments to receive an early indication from government departments for the proposed layout to be acceptable under legislation. This will include safety measures such as emergency vehicular access for fire fighting. Chan (1998) further states that development in Hong Kong is controlled through planning matters, building matters, lands matters and environmental matters, which are administered by different government authorities. Generally, standards and good practices are expected from these controls on health and safety. There are also related Ordinances that might affect development. His views are based on real estate development, and not specifically on design aspects. According to Chan, Mok, and Scott (2001), the building control system in Hong Kong is to enforce health and safety in and around buildings. There are eight aspects for a comprehensive and supportive building control system: (i) Building Law: providing regulations, statutory instruments and codes of practice etc (can be on Performance or Prescribed basis) (ii) Maintaining a building control institution backed up by fair administrative provisions (iii) Accreditation of test laboratories and materials or products of a 3rd party (iv) Delegation of power to the private sector: involving professional registration of statutory agents (v) Promotion of building related education and setting standards with constant review through R&D (vi) Availability of reasonable professional indemnity insurance for consumer protection (vii) Law Reform: reviewing legislation to cap tort and statutory liabilities to a reasonable level acceptable to society, and (viii) Support from an objection and appeal mechanism with transparency and public participation in the administration. At the levels of land lease and planning, safety control is exercised through density, and details of the safety control can be seen in the Buildings Ordinance. Hence,

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as a pioneer city with a high-density mode of development, a review of Hong Kong’s development of the Buildings Ordinance in relation to safety issues will be useful.

6.5 A Review of the Evolution of Buildings Ordinance in Hong Kong Hong Kong with an average population of about 6,700 persons per km2 . and rising to 116,000 persons per km2 . in its densest area is extreme high density. This means the utilization of urban land must be maximized (Pun, 1996). The result is vertical pileup of developed floor space to accommodate more people and activities on any individual piece of land. Concentration of development allows communal facilities and infrastructure to be provided at lower costs. However, high density may also lead to overcrowding and undesired environmental pollution (Pun, 1994) to render health and safety at risk. This is the situation when development control is necessary to provide an order in the building of the city. However, such control may lead to standardized architectural solutions with the prime objection to meet efficiency. Up to present, development does not only meet with density, which is a quantitative measure but also environmental awareness, which is a qualitative sense. Chief Executive, Donald Tsang in his 2007–2008 Policy Address in Hong Kong has advocated the concept of “progressive development” to integrate sustainability with the built environment to make “quality life and quality city”. A cleaner city with greener environment is expected. The concept of safety is extended beyond the building to the urban environment, and even the global environment (Hong Kong Government, 2007). The legislative control for design in the level of buildings takes the form of the Buildings Ordinance and related Building Regulations (Building Authority, 1997) and Codes of Practice. These had started from the early beginnings of Hong Kong as a colony and gradually evolved through years of actual development with advancement of construction technology, increase of population density and addition of complications for building design. To thoroughly reveal the building code, a brief discussion on its historical evolvement is necessary. When the colony started in 1841 and the first land sale took place on 14th June, development was mainly controlled through lease conditions. In 1844, the Ordinance for the Preservation of Order and Cleanliness within the Colony of Hong Kong was the first specific development control on buildings, and dealt with dilapidated buildings and certain building materials acceptable for local construction. It was later in 1856 that the first Ordinance for control of building design was set up under the governorship of Sir John Bowring (GN 12 of 1856). This was titled as an Ordinance for Buildings and Nuisances with 19 clauses including, (i) Definitions were given for walls, floors, story, works, building and house. (ii) Requirement was also set for the construction of houses, including residential buildings, for walls, brick walls, stone walls, foundation and floors, e.g., the walls of all houses should be built of bricks or stones. Construction

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materials of walls were expressively spelt out as walls gave horizontal separation to the row houses common at that time and afforded structural and fire safety. Material of floors was not stated as timber was often used for such construction. As related to health, every house should have a safe working place and a sufficient water closet or privy. With regards to maintenance and care of buildings, all houses with deficiencies of construction have to be made good. For dangerous buildings, buildings in a ruinous or dangerous condition would be considered a nuisance. Buildings erected of any inflammable material would also be considered a nuisance. Design control for building projections was such that any projection affecting the passengers would be considered a nuisance. A Surveyor General was empowered by this Ordinance to make survey and inspection of buildings for satisfying this Ordinance.

Though this Ordinance is brief compared with the present Ordinance, it forms the basis to expand into the present Buildings Ordinance, Building (Administration) Regulations Building (Planning) Regulations and Building (Construction) Regulations, by initiating the definitions, materials, passage and right of inspection. Enhancement of safety and health issues is apparent. In 1882, Osbert Chadwick, the first Chadwick Professor of Municipal Engineering at University College London, reported on the poor sanitary condition of Hong Kong, and the need to improve water supply, drainage, scavenging and waste collection as well as to completely revise the Buildings Ordinance (Bristow, 1984). Further recommendations include the provision of open spaces, correction of overcrowding conditions, provision of proper roads and drains before land sales and improvement made to existing buildings. Here, safety is revealed as the removal of overcrowding conditions. The standard for overcrowding was only determined when in 1887, a Public Health Bill defined overcrowding as less than 300 cubic feet of living space per person. This also stated a 4-foot gap between buildings; a backyard was required for new building and certification for compliance with the new Ordinance for new completed buildings. Quantitative Order was thus started by defining and controlling density relating to the volume of building. In 1888, the Verandah Ordinance (GN 4 of 1888) stated that verandahs should not be enclosed which would violate health and safety conditions. Eventually, in 1889, the governor, William Des Voeux amended the laws relating to the construction of Buildings, and enacted the Buildings Ordinance with 89 sections. With further outbreak of plague, Osbert Chadwick visited Hong Kong again to recommend better standards of buildings for safety and health. A new Public Health and Buildings Ordinance (GN 1 of 1903) was drawn up by Chadwick, Simpson (his co-author) and Clark (the Medical Officer of Health) (Bristow, 1984). This new Ordinance contained 266 clauses, divided into 7 parts and 11 schedules. For the construction regulations, these were mainly based on the Glasgow Building Act of

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1900 and modified for Hong Kong conditions. The control of safety in domestic buildings is revealed through the prevention of overcrowding, which was defined as “in excess of a proportion of one adult for every fifty square feet of habitable floor space or superficial area and five hundred and fifty cubic feet of clear and unobstructed internal air space”, in the urban areas. However, in the European Reservation or the Hill District, overcrowding is defined as “more than one person to every one thousand cubic feet of clear internal space” (GN 1 of 1903). The 1903 Public Health and Buildings Ordinance had certain practical deficiencies. The mixing of sanitary works with buildings had problems on operation, and led to investigation to avoid corruption. Another problem was the constant increase in population from influx of refugees from China that caused overcrowding. Advanced technology from the introduction of reinforced concrete construction with the possibility of higher standards of lighting and ventilation was another inducing factor for change. Thus, in 1935, control for buildings was separated from public health when the Public Health (Sanitation) and Buildings Ordinance was enacted. More detailed attention to safety can be seen when the standard of staircase was revised to give more safety with a tread of not less than nine inches and a rise not greater than seven inches. Fire resisting doors in communication with the staircase had to be of solid teak, not less than 2 inches thick (Section 43). This illustrated an improved standard of safety and fire protection. Requirements for lifts and fire escapes were also stated (Sections 44–45), showing the tendency to develop in the vertical dimension, and thus the need for appropriate control. For the next 20 years including the World War II period, building control was under the Buildings Ordinance of 1935. In 1955, the Buildings Ordinance (CAP 123) (68 of 1955) was enacted for amendment and consolidation of law relating to buildings. Certain parts of the 1935 Ordinance, like the provisions pertaining to the rights of adjoining owners, were re-enacted in the 1955 Ordinance. This 1955 Ordinance remains the basis of building control for the present time. Together with 3 important pieces of subsidiary legislation, the Building (Administration) Regulations, the Building (Construction) Regulations and the Building (Planning) Regulations, building development and design have been kept under control. This Ordinance consisted of 7 parts: Part I: Part II: Part III: Part IV: Part V: Part VI: Part VII:

Authorized Architects and Registered Contractors. Control of Building. Miscellaneous and General. Offences. Exemptions. Appeals. Repeal and Savings.

The planning and design of buildings are administered under the control of, including (i) streets; (ii) projections; (iii) heights, volumes and open spaces including scavenging lanes;

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(iv) (v) (vi) (vii) (viii)

lighting and ventilation; sanitation; staircases and fire-escapes; domestic buildings; buildings for special uses including industrial buildings, places of public entertainment and schools; (ix) seawall, breakwater, jetty, mole, quay, wharf and pier; (x) exceptional structures; (xi) timber yards, and hoardings and scaffoldings. The construction of buildings is controlled through:

(i) (ii) (iii) (iv) (v) (vi) (vii) (viii) (ix) (x) (xi)

materials; loads and stresses; foundations, floors and sites; walls and piers; roofs, flues and chimneys; structural steel work, reinforced concrete, and timber; fire-resisting construction; retaining walls; plumbing and drainage; wells; lifts and escalators.

To restrict density, the building bulk is controlled by building heights, volumes, open spaces and lanes. The height of the main wall could not exceed twice the width of the street (Regulation 17). Setbacks at an angle of 76◦ are allowed (Clause 18). This is explained as a consideration for Hong Kong’s geographical position, to allow natural lighting to streets. Volume of a building is set in a formula, depending on the location of site and use of the building (Regulation 20): Volume = Factor (F) times the width of street times the area of site For example,

Location of site

Domestic buildings

Other buildings

Abutting on one street or on two streets but not forming a corner site Abutting on two streets forming a corner site Abutting on three or more streets forming a corner site or an island site

Factor F = 1.25

Factor F = 1.75

Factor F = 1.50

Factor F = 2.00

Factor F = 1.75

Factor F = 2.25

For the purpose of above computation, no street less than 15 feet in width shall be deemed to be a street. To allow for adequate lighting and ventilation and separation from other buildings, domestic buildings are further required to provide open space, depending on location of site (Clause 22):

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Location of site

Opened space required

Abutting on one street or on two streets but not forming a corner site Abutting on two streets forming a corner site

Not less than one half of the roofed over area of such building Not less than one quarter of the roofed over area of such building Not less than one eighth of the roofed over area of such building

Abutting on three streets not forming an island site

To cater for fire separation, every domestic building will need a scavenging lane at the rear or side (Regulation 24). Under the Building (Planning) Regulations of 1956, developable space was controlled by volume. This produced development of very high density, often beyond the current social and health standards. Buildings at corner sites could reach densities of 10,000 per acre, and general cases of densities at 6,000 per acre were common. The amendment in 1962 introduced the idea of plot ratio and site coverage to control the intensity of development or the amount of developable space (Regulation 20). The previous regulations using the width of street to determine the height of buildings, which induced certain unfairness for large site fronting a narrow street, would be inhibited. The plot ratio was defined as “the gross floor area of a building divided by the area of the site on which the building is erected”. The site coverage was defined as “the area of the site that is covered by the building that is erected thereon and, when used in relation to a part of a composite building, means the area of the site on which the building is erected that is covered by that part of the building”. The plot ratio depends on the type of site, type of building and height of building. Buildings were only of two types – domestic and non-domestic. Domestic meant the use relating to habitation. A building could also have both domestic part and nondomestic part. This was called a ‘composite’ building. The regulations allowed more plot ratio with non-domestic buildings rather than domestic buildings with maximum plot ratio of 15 and 10 respectively. For additional control of safety, Ordinance No.3 of 1964 has a requirement for both the plans and the completed building to be inspected and certified by the Director of Fire Services before endorsement by the Building Authority (Section 9B). In the 1966 Building (Planning) (Amendment) Regulations, open space for domestic buildings had to be provided for at no place be less than 5 feet (amended regulation 22). This was intended to stop the previous practice of providing “Open Space” as narrow passages connecting wider areas of open space. To improve fire safety for tall buildings, a building with the uppermost storey more than 55 feet above the ground level should have 25 staircases as means of escape (amended Regulation 37). Previous control was set at 6 storeys. The 1950s to 1970s could be considered as the High-rise Era of Hong Kong buildings. During that time, multi-storey buildings were the development trend. The 1970s to 1990s could be considered the New Town Era with the start of the

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New Towns Programme in 1973 and extensive urban development. Arising from concern with universal design in buildings, the Building (Planning) (Amendment) Regulations (1984) have made provisions on planning of buildings to be used by disabled persons (Regulation 72). A Third Schedule on Disabled Persons was added to the Regulations, stating requirements on initial access, ramps, dropped kerbs, lifts, corridors, lobbies, doors, water closet cubicles, handrails, wheelchair spaces in concert hall and rooms for the disabled in hotels. Here, safety for disabled person is also of concern. In the Amendment, 52 of 1990 of the Ordinance, the Scheduled Areas with sensitive geotechnical conditions was added. Site formation plans had to be submitted with geotechnical report. In the Amendment, 91 of 1990, priority demolition was added for consideration of certain emergency cases causing danger or nuisance to the public (Section 24). Other amendments included dangerous hillside, naming of streets, offences and appeal tribunal. To care for safety in construction, the Buildings Amendment (1995) included restrictions to the use of “hand-dug caisson”, which was defined as any foundation or earth-retaining structure, or part thereof, the construction of which includes the excavation of a shaft in the ground by means of digging carried out by any person inside the shaft with or without the aid of machine tools. To monitor safety in construction, the Amendment, 54 of 1996, dealt with new formations for the Registration Ordinance and the supervision plan. The registration Ordinance included the Architects Registration Ordinance (CAP 408), the Engineers Registration Ordinance (CAP 409), and the Surveyors Registration Ordinance (CAP 417). There was also requirement for registration of general contractors and specialist contractors. The “supervision plan” was determined as a requirement for consent to building works (Section 16(3)). This means a plan setting out the plan of safety management of building works or street works lodged by an authorized person with the Building Authority, (a) prior to or at the time of application for consent to the commencement of building works or street works; or (b) as a result of carrying out urgent works, and includes a revised supervision plan lodged as a result of any amendments necessary under this Ordinance. For the present (Hong Kong Government, 2008), the Hong Kong Building (Planning) Regulations have evolved to consist of the following: Part III, heights, site coverage, plot ratio open spaces and lanes (Regulations 16–28), deals with the extent of built-up spaces, controlling the bulk of development. Part IV (Regulation 29–37) deals with Lighting and Ventilation Requirement of buildings, affecting the fenestration and hence the elevation design of buildings. Part V, Staircases, fire escapes and access for fire fighting and rescue purposes, (Regulations 38–44) affects the internal planning for staircases, lifts and corridors. As these items often form the non-saleable portion of real estate development, they are usually kept minimum in size and just basic compliance with the Regulations.

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PART I PART II PART III PART IV PART V PART VI PART VIA PART VII PART VIII PART IX PART X

General Projections Heights, site coverage, plot ratio, open spaces and lanes Lighting and ventilation Staircases, fire escapes and access for fire fighting and rescue purposes Domestic buildings Places of public entertainment Temporary buildings Repealed Hoardings, covered walkways and gantries Miscellaneous

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Reg. 1–6 Reg. 7–15 Reg. 16–28 Reg. 29–37 Reg. 38–44 Reg. 45–49 Reg. 49A–49E Reg. 50–58 Reg. 64–70 Reg. 71–72

Part VI (Regulation 45–49) deals with Domestic Buildings on a few other aspects. Regulation 45 requires domestic buildings to provide kitchen accommodation. Regulation 46 deals with tenement house, which means “any building in the domestic part of which any living room is intended or adapted for the use of more than one tenant or sub-tenant”. Provisions on windows and kitchens are stated. For residential flats with only single tenement, this Regulation does not apply. Regulation 47 states no domestic building shall be erected against a retaining wall or massive rock face exceeding 4.5 m. Regulation 48 allows retaining wall to form part of a domestic building, subject to Regulation 27. Regulation 49 states domestic building not to combine with incompatible trades such as dangerous goods, motor repair, vulcanizing, automobile painting, other painting, and dry-cleaning, etc, as these are environmental polluting trades. The Building (Construction) Regulations deal with building materials, imposed loads to buildings, foundations, walls, curtain walls, roofs, structural use of concrete and retaining walls. Regulation 38 states the concrete external wall has to be not less than 100 mm thick, which is a common local practice. Part XV on fire resisting construction states the objectives for building against fire: (a) (b) (c) (d)

stop the spread of fire within building provide adequate resistance to fire maintain structural stability in case of fire stop the spread of fire to other buildings

In addition to the Buildings Ordinance and Building Regulations, there are codes of practice to be observed in Hong Kong. Codes of Practice that are more significant to building design include the following, • The Code of Practice for Fire Resisting Construction includes general provisions and specific requirements for fire resisting construction. There are two approaches to fire safety. One is to comply with the prescriptive provision in

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the code and the other is an alternative approach, in particular, suitable for buildings of special hazards. The first approach is usually adopted as the alternative approach requires time and costs for research and development. The concept of fire resistance is by means of compartmentation, the separation using walls and floors of different spaces to prevent spread of fire. The measurement unit and the standard for resisting fire is the fire resistance period, which is related to the material of construction and its dimension. Openings through fire resisting walls can be made by means of protected lobby with doors. Protection against spread of fire and smoke between floors of some building can be made by a barrier of not less than 450 mm measured vertically. Protection of adjoining buildings can be by fire-resisting external walls. Any openings have to be located at least 450 mm from the common boundary. • The Code of Practice for Minimum Fire Service Installations and Equipment and Inspection, Testing and Maintenance of Installations and Equipment deals with the actual installations and equipment to deal with fire fighting. Smoke detectors, sprinkler heads, exit signs, fire hydrants, hose reels and fire alarms, etc, have to be incorporated into the architectural design. The extent and particulars of installations depend on the use, location and size of the building. • The Code of Practice for Means of Access for Fire fighting and Rescue makes provision for access staircase, fireman’s lifts and fire fighting and rescue stairways. Access staircase means “a staircase so designed and constructed as to allow firemen safe and unobstructed access to all floors of a building in the event of a fire”. Fire fighting and rescue stairway means “a stairway accommodating an access staircase and a fireman’s lift”. An access staircase can still be used as an escape staircase. But the fire fighting and rescue stairways have to be on the external wall. The type and number of staircases required depends on the type and complexity of the building, ranging from no requirement for a 3-storey domestic building up to very stringent control on industrial undertakings and basements exceeding 2 storeys. The presence of the fire fighting and rescue stairways on the elevation can be a restraint on the design of the building. • The Code of Practice for the Provision of Means of Escape in Case of Fire makes provisions on means of escape in the event of fire or other emergencies. To assess the requirements for means of escape, the population of the building is assessed by the intended use and usable floor area. The term usable floor area means “the aggregate of the areas of the floor or floors in a storey or a building excluding, unless otherwise specified, any staircases, public circulation space, lift landings, lavatories, water-closets, kitchens in self-contained flats, and any space occupied by machinery for any lift, air-conditioning system or similar service provided for the building”. Based on the population capacity of a room or storey, the minimum number of exit doors or exit routes with required widths can be worked out. The staircases should have the capacity of evacuating the residing people efficiently based on a standard discharge value working from the width of staircase and the number of storeys served. There are also certain restrictions on direct distance and travel distance, which have to be complied with. Such restrictions vary according to the use of the premises and the protection on the exit routes.

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In summary, the current Buildings Ordinance (2008) has sections controlling building design through safety, town planning, street works and projections. Safety is considered as provision of escape route and access for fire fighting in case of fire. On the other hand, the Outline Zoning Plan issued by the Town Planning Board has to be complied with by buildings on planning matters. Streets have to be constructed based on a certain public standard. Projections from buildings onto streets are generally permitted to protect the pedestrians on the streets. The current Building (Planning) Regulations have more specific control variables on building design. The control on plot ratio restricts the density and hence affects the internal planning to achieve the highest efficiency. Control on lighting and ventilation affects the provision of windows and hence the elevation design. The control on staircases affects safety and the internal planning which may influence the elevations. The control on provisions for persons with a disability affects some architectural details and requires additional space for certain functions. There are also a number of Codes of Practice affecting building design. The Code of Practice for Fire Resisting Construction affects the separation between different spaces and different buildings. The Code of Practice for Fire Service Installations deals with details of fire fighting installations and related builder’s work items.

Fig. 6.7 Corridor access in Hong Kong buildings for means of escape

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Provisions are based on the floor area. The Code of Practice for Means of Access gives provisions to install access staircases as regard to use and degree of fire hazard. The Code of Practice for Means of Escape determines the amount of escape staircases, based on the specific use and the floor area (Fig. 6.7). For the building code, the trend to consider environmental awareness can be seen in the issue of Building (Efficiency) Regulations in 1995, continuous study on the environmental aspect like the Comprehensive Environmental Performance Assessment Scheme for Buildings (CEPAS, Buildings Department, 2007) and when the Buildings Department joined with Planning Department and Lands Department to publish Joint Practice Note for Green and Innovative Buildings (JPN, 2004, 2006).

6.6 Comparative Review of Legislation in Asian Cities The aspects of safety can be categorized as structural safety, fire safety and life safety due to other risks. Yet, in Asian cities where high density forms the mode of living, density control through developable space is the fundamental mechanism to derive safety guidelines.

6.6.1 Density In Hong Kong, the Developable Space is calculated by gross floor area (GFA) (Wong, 2000a). According to the Building (Planning) Regulation 23(3)(a): “GFA is the area contained within the outer surface of external walls of a building measured at each floor level (including any floor below the level of the ground), together with the area of each balcony in the building, which shall be calculated from the overall dimensions of the balcony (including the thickness of the sides thereof), and the thickness of the external walls of the building”. This is related to the site area, and expressed as “plot ratio”. Due to the high value of real estate in Hong Kong, the way of interpreting the gross floor area is essential in the work of government. In determining the GFA, the Building Authority may disregard any floor space that is constructed or intended to be used solely for parking motor vehicles, loading or unloading of motor vehicles or occupied solely by machinery or equipment for any lift, air-conditioning or heating system or any similar service. Projecting windows and minor projections such as sun-shading devices that are genuine energy efficiency measures are also exempted from the GFA calculation. The maximum gross floor area of a site is determined by plot ratio and site coverage, which may be increased by bonus gross floor area through dedication of ground floor or first floor for public passage, subject to the acceptance by government. In China, developable space is controlled by usable floor area (UFA). UFA in each unit is equal to the sum of the floor areas of bedrooms, living rooms, dining rooms, corridors, kitchens, toilets, storerooms and wardrobes. The internal staircases in split level units shall be calculated depending on the total floor area.

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The internal finishes are also included. Smoke vents, ventilation ducts, pipe ducts are exempted in the usable floor area calculation. In Singapore, the developable space is controlled by gross floor area (GFA). Here, GFA is the total area of the floor space within a building measured from the external wall. This includes the total of all covered floor areas, except otherwise stated, and uncovered areas for commercial uses of the building (Urban Redevelopment Authority, 1999). In Japan (Ministry of Construction, 1990), the ratio of built-upon area is controlled under a system called “kenpeisitzu”, considering both the floor area and the area of the site. This is also similar to the plot ratio control; the kenpeisitzu also changes depending on the location of the site.

6.6.2 Structural Safety In Hong Kong, the Registered Structural Engineer is responsible for structural safety of buildings with the building works co-ordinated by the Authorized Person. Under the Building (Construction) Regulations, the dead loads, live loads and wind loads are checked and calculated to form the substructure (foundation) and superstructure. The structural enclosure for a space has to serve the dual function of structural safety and fire safety. Here, the concept of fire rating is introduced so that a structural element such as a concrete slab has to withstand combustion due to fire for a certain period. Another example is the requirement of concrete cover for the steel reinforcement in a structural element to serve as fire protection. Besides the building structure, there are ground conditions for structural safety. The problems due to geotechnical matters are taken care of by Registered Geotechnical Engineers in Hong Kong. There are also sensitive ground zones such as those with marble caves, slope areas, close vicinity with the underground mass transit, etc., which require strengthened ground works. In Japan, buildings have to be designed safe from dead load, live load, snow load, wind pressure, ground pressure, water pressure, earthquakes or other vibration or shook in accordance with the Building Standard Law of Japan. Landslides are also considered in certain sites for appropriate measure of safety. In China, the particular structural requirement can vary in different provinces, yet it is an important consideration for building codes. This is also rated through a marking system of the structural safety, ranging from unsatisfactory to satisfactory, fairly reasonable and reasonable. The purpose of which is to give a fair evaluation, to enhance the quality, and to raise the standard of residential buildings. For protection against fire, there are active and passive means. The active means include fire detection, fire extinction and access to fire fighting and rescue while the passive means include structural fire protection and means of escape.

6.6.3 Fire Safety In Hong Kong, the fire safety is controlled by the Building (Planning) Regulation, Code of Practice for the Provision of Means of Escape in Case of Fire, Code

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of Practice for Means of Access to Firefighting and Rescue, Code of Practice for Fire Resisting Construction, Code of Practice for Minimum Fire Service Installations and Equipment and Inspection and Testing of Installations and Equipment. According to the Building (Planning) Regulation 43: Every part of any building intended for habitation shall be not more than 24 m from a staircase, passage or other normal means of egress.

According to the Code of Practice for the Provision of Means of Escape in Case of Fire Regulation 14: Direct distance should be maximum 15 m. Travel distance should be maximum 30 m. Sum of direct distance and travel distance should be maximum 36 m

The Fire Safety (Buildings) Ordinance enacted in 2001 states the requirement for fire service installation on the non-domestic (non-residential) part of composite buildings (buildings with both residential and non-residential use) as well as improvement for the domestic part. In China, buildings have to be designed with enough protection from fire risk. Buildings are divided into four grades. According to the maximum length and maximum area for each compartment, there will be different limitations on maximum escape distance, minimum width of escape route, minimum width of staircase, etc. The emergency vehicle access in China shall have a width of at least 3.5 m and a clear height of at least 4 m. The distance from the buildings to the boundary of site should not be greater than 160 m. There are also requirement for minimum treads and the maximum risers for buildings of different uses. Fire control rooms, pump rooms, A/C machine rooms, lift machine rooms, TBEX rooms and switch rooms, etc. shall have 3 h FRP for enclosing wall, 2 h FRP for enclosing slab, and 1.2 h FRP for exit doors. In addition, there are regulations which control the maximum area of each compartments, the FRP of enclosing walls/slabs of rooms with different functions, the requirements for interior decoration, the requirements for MVAC systems, the provision of fire extinguishing facilities, the provision of lighting and electricity in case of fire, etc. The depth or dimensions of various kinds of construction materials with different FRP are also stipulated in the regulations. For residential buildings, the maximum travel distance shall fulfil the following requirements: (a) The distance from any points of the room to the door shall not be more than 15 m. (b) The distance from exit door to the nearest fire escape staircase shall not be more than 30 m if the room is located between two or more fire escape staircases. If the room is located in a deadend, the maximum distance from exit doors to the nearest fire escape staircase shall be 15 m. In a single loaded corridor, the minimum width of the escape route shall be 1.2 m whereas in a double loading corridor, the minimum width of the escape route shall be 1.5 m. In both cases, the minimum width of exit doors shall be 1 m. In case of

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high-rise buildings, the minimum width of the exit route for a single loading corridor shall be 1.2 m, and 1.3 m for a double loading corridor. The minimum width of the exit doors shall be 1.1 m. The width of the staircase shall be at least 1.1 m; the treads shall be not less than 0.25 m and the risers not more than 0.18 m. In the Building Standard Law of Japan, according to Article 23, with respect to wooden buildings within urban areas, the portion of external walls liable to catch fire shall be made of earth plaster or of such construction as has a fire preventive effect not less than that of earth plaster external walls. According to Article 25, with respect to wooden buildings whose total floor area (or the aggregate of total floor areas if there are two or more wooden buildings on the same site) exceeds 1,000 m2 , the portion of external walls and soffits liable to catch fire shall be of fire preventive construction and roofs or non-combustible materials. As the chapter is on tall buildings, only regulations that relate to tall buildings are discussed.

6.6.4 Fire Escape and Fire Fighting Being an important element of safety, the staircase design in Hong Kong, China and Japan are controlled respectively by the Building (Planning) Regulations, the Architectural Design Building Code and the Building Law for determining the width, landing, treads and sizes of the staircase (Figs. 6.8, 6.9 and 6.10). In Hong Kong, exit design and provision of fire fighting equipment are governed by the corresponding Code of Practices as enforced by the Building (Planning) Regulations. In China, the aims of the regulations are to provide safe exit routes and enough means of escape in the case of emergency. There are limitations for vehicular exit routes of some development, which will experience heavy traffic, such as car parks, patrol stations, etc. The traffic exits of such development should be at least 70 m from any intersection point of main roads; at least 5 m from any zebra crossing, traffic light, etc.; at least 10 m from station of public transport; and at least 20 m from school, public park, kindergarten, etc. Also, there are limitations for buildings like cinemas, theatres, city halls, exposition buildings, commercial centres, etc, where the crowd will gather. In Japan, regulations are laid down for structural strength, fireproof construction, fire prevention construction, fire separation, evacuation facilities, etc. Dilapidated buildings are dangerous. Especially for high-rise buildings, falling concrete, falling windows, poor drainage pipes, etc, can cause immediate or potential hazards. Hence, building maintenance becomes important through the life of buildings. In this regard, the Building Department in Hong Kong has promoted building safety through publications such as the “Building Maintenance Guidebook”, “An Introduction to the Co-ordinated Maintenance of Building Scheme”, “A Safe Living Environment Depends on Owner’s Initiative”, “What you need to know about drainage pipe maintenance”, “Building Safety Loan Scheme”, “Aluminium Windows Maintenance” and “Falling Concrete Kills, Timely Maintenance Heals”, etc.

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Fig. 6.8 Staircase in Hong Kong

6.7 A Positive Approach for Safety The control of safety through legislation can be quite negative as only the minimum standard is stated in the Building Law. Also, due to further complication in administration and functional complexities, the designer or developer will tend to compromise by the design not achieving the best result in terms of the whole life of the building or from a more holistic consideration of the environment. The following

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Fig. 6.9 Staircase in China

examples illustrate possibilities in Asian cities for the creation of better quality habitat through encouragement and evaluation means, which present a workable direction for the way forward.

6.7.1 Building Award in Singapore The Evaluation System in China states different levels of achieving safety through meeting different standards to promote quality in building design, rather than just meeting the basic workable standards. However, a more positive approach can be seen in the Singapore Building and Construction Authority aim to promote quality through building awards. Based on its mission “to shape a safe, high quality,

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Fig. 6.10 Staircase in Japan

sustainable and friendly built environment”, the Design and Engineering Safety Excellence Awards was organized in late 2007 to recognize efforts by the design team to ensure safety in design, construction and maintenance of a building through innovative design processes, measures and solutions (Fig. 6.11). The award assessment criteria are: a. Design processes and solutions that emphasize safety, such as the use of innovative features or materials, design solutions that can be constructed safely without compromising buildability or economy, collaboration between the structural engineer and other project team members, competent staff, peer reviews, specialist input and verification tests.

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Fig. 6.11 Double volume space and open kitchen design in Japan

b. Quality approach in design, details and specifications, including comprehensive design analysis, proven detailing and clearly spelled out specifications. c. Design for safe operation and maintenance that incorporates provisions for safe inspection of key structural elements, features that facilitate maintenance and/or replacement of structural components as well as durability considerations.

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d. Construction quality and safe construction processes such as well-defined builder’s site management and supervision, Qualified Person’s supervision and inspections, testing, reporting and monitoring programme. e. Public safety consideration such as safety provisions and management of the construction process, structural systems that minimise impact on neighbourhood during construction, no adverse feedback regarding safety and environmental issues. To ensure a fair system, the Building and Construction Authority also states the following assessment criteria: Building and Civil Engineering Projects A

Design

70%

(1) Structural design processes and solutions that emphasize safety Ingenious design processes and solutions to meet challenges posed by the unique nature of the project: (i) (ii) (iii) (iv)

Elegant choice of special or innovative features, advanced structural system, including robust design concept, or materials to address the challenges and risks; Design solutions that can be constructed safely without compromising buildability or economy; Careful integration of design between the structural engineer, architect and other design professionals; Judicious use of competent staff, peer review, specialists input, and verification tests

40%

(2) Quality approach in design, details and specification (i) (ii) (iii)

Comprehensive design analysis and checks; Well thought through and excellent attention to detailing; Well defined particular specifications to achieve design intent relating to special or key elements of structural system

15%

(3) Design for safe operation and maintenance (i) (ii)

B

Provisions for safe inspection of key structural elements after completion; Design features that facilitate maintenance and/or replacement of structural components; (iii) Durability considerations Construction (1) Construction quality and safe construction processes Commitment to high standards of site management and building safety beyond statutory duties: (i) Well-defined Builder’s site management and supervision plan; (ii) QP’s supervision and inspection, testing and monitoring programme; (iii) Excellent or innovative construction method

15%

30%

15%

(2) Public Safety considerations Minimise impact of construction activities to the immediate neighbourhood: (i) (ii) (iii)

Safety provisions and management of the construction; Adoption of structural systems that minimise impact to neighbourhood during construction; No adverse public feedback/complaints regarding safety and environmental issues

15%

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In such holistic consideration of design construction and maintenance, safety as a basis for human habitat can be enhanced as a factor of sustainability.

6.7.2 Intelligent Building Index Another approach for future residential buildings in Asia is the Intelligent Building. Although there is no universal definition, the Intelligent Building is expected to be interactive with people and environment, self-caring to achieve a harmonious relationship of building and nature as well as highly adaptive to change and advancement of technology and communication (AIIB, 2001). This will be fostered by a thorough comprehension of needs and collaboration of building structure, building systems, building management and building services. There are nine modules formulated by members of the Asian Institute of Intelligent Buildings: (M1) Environmental friendliness – health and energy conservation (M2) Space Utilisation and flexibility (M3) Human comfort (M4) Working efficiency (M5) Culture (M6) Image of high technology (M7) Safety and security measures – fire, earthquake, disaster and structural damages etc. (M8) Construction process and structure (M9) Cost effectiveness – operation and maintenance with emphasis on effectiveness. The “safety and security measures” can be implemented through functional requirement and technologies such as property management, facility management, fire detection, fire fighting, security control, building automation, energy saving, etc. These will accumulate to a certain quality that is further measured through the “Safety and Security Index”, which is roughly 10% of the whole Intelligent Building Index. This index is formulated with factors, which may be existing or non-existing according to the locality. The factors are earthquake monitoring devices, wind load monitoring devices, structural monitoring devices, structural control, tile debonding, terrorist attack consideration, indefensible space, average width of corridor, average usable area in percentage of total gross floor area, means of escape, circulation for the disabled, fire detection and fire fighting, fire resistance, means of access, electrical wiring regulation, reliability of elevator systems, time to identify trapped passengers without a mobile phone, closed circuit television (CCTV), response to special event, security control system, number of unmonitored exits and entrances, advanced AI-based security system, time needed to report a disastrous event to the building management, time needed for public announcement of disasters, time for total egress, quality of systematic escape route plan, essential electric power, comprehensive scheme of preventive maintenance, maintainability

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of installation, thermal comfort and indoor air quality and special feature(s) recommended by the auditor. This can be seen as another positive means to encourage better quality habitat. A sense of competition for quality can be generated through designers and private developers to provide the best habitat for people. Legislation as a means of forced control alone will not be successful. It requires the complement of means of encouragement and promotion.

6.8 Concluding Remarks To achieve sustainability, all the three interrelated factors, “firmitas”, “utilitas” and “venustas”, have to be met for quality buildings. There is actually no particular sequence of the three factors as all three have to be well integrated to evolve the habitation, which is both physically and mentally pleasant. The emphasis or sequence may be from the viewpoint of the particular character acting as tenant, landlord, designer or code administrator. Hence, form, function and safety become inseparable issues in the high-density environment. Asian cities are noted for their high-density living, which gives benefits of high efficiency, strong community sense and energy saving. Yet, un-harmonized situation of high density can lead to conflicts of overcrowding. Safety becomes the critical issue for determining the right balance for control or freedom. Legislation through the building law becomes the means of control or standards of criteria for regulating the dense built environment. Differences of legislation are observed in various Asian cities, and are understood as the results of variation in the culture of habitation and degree of development. For instance, many Japanese homes still keep at least one traditional Japanese styled room called “washitsu”, which is a flexible empty room furnished with tatami flooring and shoji. This can serve as a family room during the day, and a bedroom during the night. However, in Hong Kong, the kitchen and the bedroom have to be naturally lit and ventilated as well as separable from the living areas for safety and health precautions. In Singapore, open kitchen and double-volume habitable spaces are acceptable. Hence, the spirit of legislation varies according to the local societal culture. In Hong Kong, because of the high economic pressure and high real estate value, regulatory measure through strict control is exercised. Redefinition of the means of control and terms of floor area can be a positive approach for quality (Wong, 2000b). In Singapore, a more positive approach to design is through celebration of design excellence. The holistic view of design construction and maintenance is worth a reference. In Japan, despite the strict control and local cultural characteristics, innovation is still encouraged through projects designed by international architects. In China, due to the great differences in societal needs, different grading of buildings can serve the appropriate requirement. Still under testing and review, the Intelligent Building Index may serve to lead the future trend of the Asian residential buildings. Against the rapid development in Asian cities, the way forward for safety in highrise will still be along sustainability aspect, whereby a healthy and safe habitat prevail to suit the local cultural identity and technology as well as to endure and make the home for people.

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References AIFB (Asian Institute of Intelligent Buildings). (2001). The intelligent building index manual. Hong Kong: City University of Hong Kong. Bristow, R. (1984). Land-use planning in Hong Kong – History, polices and procedures. Hong Kong: Oxford University. Building Authority. (1997). Building ordinance and allied regulations, Chapter 123. Hong Kong: Hong Kong Government. http://www.bd.gov.hk/english/index.e.html Building Control Act. (1999). Building Control Act, Chapter 29, Singapore. Last accessed December 15, 2009, from http://www.bca.gov.sg/BuildingControlAct/building_control_act. html Buildings Department. (1998). Building (planning) regulations. Hong Kong: Reg. 20 to 23. Buildings Department. (1999). Building development and control in Hong Kong. Hong Kong: Hong Kong Government. Buildings Department. (2007a). Fire safety (buildings) ordinance. Hong Kong. Buildings Department. (2007b). Comprehensive environmental performance assessment scheme for buildings (CEPAS). Hong Kong: Hong Kong Government. CCIP (China Construction Industry