DESIGNING HIGH-DENSITY CITIES HIGH-DENSITY DESIGNING ‘Designing High-Density Cities is a unique Compact living is sustainable living. High- contribution. It is an excellent overview of density cities can support closer amenities, the state of the art on design process for encourage reduced trip lengths and the cities presenting high densities. The book use of public transport, and therefore is an outcome of long standing research in reduce transport energy costs and carbon the area of urban sustainability and includes emissions. High-density planning also helps contributions from internationally acclaimed to control the spread of urban suburbs researchers and building scientists. This is into open lands, improves efficiency in a valuable reference not only for academics urban infrastructure and services, and but also for architects and practitioners.’ results in environmental improvements Mat Santamouris, Professor of Energy that support higher quality of life in cities. Physics, University of Athens, Greece Encouraging, even requiring, higher density urban development is a major policy and a ‘An outstanding collection of papers on a central principle of growth management key issue in planning today. Starting with programmes used by planners around the the essentials of high-density building, this world. However, such density creates design book then explores the complex relations challenges and problems. In this book, a of high-density metropolitan areas. It goes collection of experts in each of the related without saying that the combination of such architectural and planning areas examines important themes fills a gap in our knowledge these environmental and social issues, and that no planner can ignore this book’ and argues that high-density cities are a Tejo Spit, Professor of Urban and Regional sustainable solution. It will be essential Planning, Utrecht University, reading for anyone with an interest in The Netherlands sustainable urban development. ‘A distinctive and comprehensive selection of conceptual ideas covering the “art and science” of sustainable city design.’ Khee-Poh Lam, Professor of Architecture, Carnegie Mellon University, USA DESIGNING Edward Ng Edward HIGH-DENSITY Edward Ng is a Professor at the School of Architecture, The Chinese University of Hong Kong, and an environmental consultant to organizations and governments. CITIES For Social & Environmental Sustainability www.earthscan.co.uk Earthscan strives to minimize its impact on the environment Urban Planning / Architecture Edited by Edward Ng Prelims.qxd 11/17/2009 2:55 PM Page i Designing High-Density Cities Prelims.qxd 11/17/2009 2:55 PM Page ii Prelims.qxd 11/17/2009 2:55 PM Page iii Designing High-Density Cities for Social and Environmental Sustainability Edited by Edward Ng publishing for a sustainable future London • Sterling, VA Prelims.qxd 11/17/2009 2:55 PM Page iv First published by Earthscan in the UK and USA in 2010 Copyright © Edward Ng, 2010 All rights reserved ISBN: 978-1-84407-460-0 Typeset by Domex e-Data, India Cover design by Rob Watts For a full list of publications please contact: Earthscan Dunstan House 14a St Cross St London, EC1N 8XA, UK Tel: +44 (0)20 7841 1930 Fax: +44 (0)20 7242 1474 Email: [email protected] Web: www.earthscan.co.uk 22883 Quicksilver Drive, Sterling, VA 20166-2012, USA Earthscan publishes in association with the International Institute for Environment and Development A catalogue record for this book is available from the British Library Library of Congress Cataloging-in-Publication Data Designing high-density cities for social and environmental sustainability / edited by Edward Ng. p. cm. Includes bibliographical references and index. ISBN 978-1-84407-460-0 (hardback) 1. City planning--Environmental aspects. 2. Sustainable urban development. 3. Urban ecology (Sociology) I. Ng, Edward. HT166.D3869 2009 307.1'216--dc22 2009012710 At Earthscan we strive to minimize our environmental impacts and carbon footprint through reducing waste, recycling and offsetting our CO2 emissions, including those created through publication of this book. For more details of our environmental policy, see www.earthscan.co.uk. This book was printed in the UK by The Cromwell Press Group. The paper used is FSC certified. Prelims.qxd 11/17/2009 2:55 PM Page v Contents List of Figures and Tables xi List of Contributors xxi Foreword by Sir David Akers Jones xxix Preface xxxi Acknowledgements xxxvii List of Acronyms and Abbreviations xxxix PART I: AN UNDERSTANDING OF HIGH DENSITY 1 Understanding Density and High Density 3 Vicky Cheng Physical density 3 Building density and urban morphology 9 Perceived density 12 High density 13 Conclusions 16 2 Is the High-Density City the Only Option? 19 Brenda Vale and Robert Vale The post-oil scenario 19 The food equation 20 Wastes and fertility 23 Low density or high density? 24 Conclusions 24 3 The Sustainability of High Density 27 Susan Roaf Population and the people problem 27 Resource depletion 33 Pollution 36 Conclusions: Avoid the Ozymandias syndrome 37 4 Density and Urban Sustainability: An Exploration of Critical Issues 41 Chye Kiang Heng and Lai Choo Malone-Lee Sustainability and planning 41 Historical review 42 Density and sustainability 43 Conclusions 50 Prelims.qxd 11/17/2009 2:55 PM Page vi vi DESIGNING HIGH-DENSITY CITIES PART II: CLIMATE AND HIGH-DENSITY DESIGN 5 Climate Changes Brought About by Urban Living 55 Chiu-Ying Lam Temperature 55 On climate changes brought about by urban living 55 Wind 57 State of the sky 57 Evaporation 59 Thinking about people 60 6 Urbanization and City Climate: A Diurnal and Seasonal Perspective 63 Wing-Mo Leung and Tsz-Cheung Lee Urban heat island (UHI) intensity 63 Diurnal variation of UHI intensity 64 Seasonal variation of UHI intensity 66 Favourable conditions for high UHI intensity 67 Conclusions 67 7 Urban Climate in Dense Cities 71 Lutz Katzschner Introduction 71 Problems 72 Urban climatic maps 74 Urban climate and planning 78 PART III: ENVIRONMENTAL ASPECTS OF HIGH-DENSITY DESIGN 8 Thermal Comfort Issues and Implications in High-Density Cities 87 Baruch Givoni Thermal comfort 87 Recent research on comfort 90 Conclusions: Implications for building design and urban planning 104 9 Urban Environment Diversity and Human Comfort 107 Koen Steemers and Marylis Ramos Introduction 107 Background 108 Monitoring outdoor comfort 108 Conclusions 116 Prelims.qxd 11/17/2009 2:55 PM Page vii CONTENTS vii 10 Designing for Urban Ventilation 119 Edward Ng Introduction 119 Urban ventilation in high-density cities 119 Wind velocity ratio for urban ventilation 120 Building and city morphology for urban ventilation 121 Case study: Hong Kong 124 Design guidelines 130 Conclusions 135 11 Natural Ventilation in High-Density Cities 137 Francis Allard, Christian Ghiaus and Agota Szucs Introduction 137 Role of ventilation 138 Cooling potential by ventilation in a dense urban environment 141 Natural ventilation strategies in a dense urban environment 156 12 Sound Environment: High- versus Low-Density Cities 163 Jian Kang Sound distribution 163 Sound perception 168 Noise reduction 177 13 Designing for Daylighting 181 Edward Ng Introduction 181 Context 181 Graphical tools for design 182 The need for daylight 184 Towards high density 186 A tool for high density 188 The way forward 190 Conclusions 193 14 Designing for Waste Minimization in High-Density Cities 195 Chi-Sun Poon and Lara Jaillon Introduction: Waste management and waste minimization 195 Designing for waste minimization 200 Conclusions 206 15 Fire Engineering for High-Density Cities 209 Wan-Ki Chow Introduction 209 Possible fire hazards 210 Fire safety provisions 211 Prelims.qxd 11/17/2009 2:55 PM Page viii viii DESIGNING HIGH-DENSITY CITIES Performance-based design 213 Atrium sprinkler 214 Structural members under substantial fires 214 Super-tall buildings 217 Glass façade 219 Application of performance-based design in Hong Kong 219 Necessity of full-scale burning tests 220 Fire engineering as a new profession 221 Conclusions 222 16 The Role of Urban Greenery in High-Density Cities 227 Nyuk-Hien Wong and Yu Chen Introduction 227 Reducing ambient air temperature with plants 229 Reducing surface temperature with plants 243 Challenges in incorporating urban greenery in high-density cities 257 17 Energy in High-Density Cities 263 Adrian Pitts Introduction 263 Energy demand 263 Energy supply 266 18 Environmental Assessment: Shifting Scales 273 Raymond J. Cole Introduction 273 Building environmental assessment methods 274 Shifting scales 277 Blurring boundaries 279 High-density urban contexts 280 Conclusions 281 PART IV: HIGH-DENSITY SPACES AND LIVING 19 The Social and Psychological Issues of High-Density City Space 285 Bryan Lawson Introduction 285 Privacy 287 Public policy 288 The city territory 289 Evidence-based design 290 Perception of density and satisfaction 291 What have we learned? 291 Prelims.qxd 11/17/2009 2:55 PM Page ix CONTENTS ix 20 Sustainable Compact Cities and High-Rise Buildings 293 Sung Woo Shin History and background 293 Current status, direction and effect of high-rise buildings 294 High-rise buildings – their trend and efficiency in terms of the sustainable compact city 298 Conclusions 307 21 Microclimate in Public Housing: An Environmental Approach to Community Development 309 John C. Y. Ng Introduction 309 Sustainable community: A holistic approach 310 Community development: In pursuit of economic sustainability 310 Community development: In pursuit of social sustainability 311 Community