The evolution of buildings and cities. Adapting to changing environmental conditions from urbanization

Welcome to this edition of Architectural Science Review (ASR). It is the first of 2018. A number of issues have come across my desk this year and reading the papers in this Edition reminds me of a number of challenges that face Architectural Science Research. Traditionally the research in this field has focused on the way the scientific phenomena of heat, light and sound relate to architecture, and importantly the concepts and methodologies used in understanding these phenomena. However, these concepts and methodologies have been used to examine a range of challenges concerning the built environment and the human condition therein, be it the human subjective or objective response to that environment. In addition, different aspects of architecture are unpacked and researched using as their foundation the scientific method. Issues emerge in both the theoretical and the practical spheres for making buildings, urban planning, structural and environmental engineering to name a few. However, ASR has made and is continuing to make a significant contribution to some of the emerging challenges of the twenty-first century.

Many of these challenges stem from the evolution of our buildings and cities in the face of changing environmental conditions. Roaf, Crichton, and Nicol 2005 in their book ‘Adapting Buildings and Cities for Climate Change’ set out the issues for this challenge. There is an important chapter in this book where they discuss the evolution of buildings and how potential changes in environmental and social upheaval were brought about by climate change. They ask the question how can buildings and cities evolve in the face of climate change? They use a case study of pre-modern and modern buildings in the Mediterranean as this is an area predicted to suffer from increased summer temperatures. They note.

What we found was that the simple Roman building evolved over the following two millennia into extremely sophisticated and efficient passive building types, but surprisingly the most sophisticated was that of the Baroque period in the late eighteenth century, since when passive design skills appear to be on the decline. (Roaf, Crichton, and Nicol 2005, 49)

Roaf et al. carried out an analysis of the buildings studied and identified 36 passive adaptive counter-measures, which were used to control indoor conditions.

The first paper in this edition follows this theme. Authored by Indrika Rajapaksha, Francesco Fiorito, Estelle Lazer and Francesca Sartogo and called ‘Exploring thermal comfort in the context of historical conservation. A study of the vernacular architecture of Pompeii’, it provides further performance information on the adaptive measures that are used in this building type. Furthermore, it argues for the need to understand and conserve the environmental conditions in these buildings for future generations. The study of Pompeii shows the interconnection between the form of city and the design of the houses. The city comprises an early type ‘row house’ with building footprint consuming most of the site. Often the building site is geometrically irregular with atria and courtyards both large and small providing the environmental living conditions. The cities become an urban typology primarily of streets and courtyards, which provide access to light and ventilation. Whilst this observation seems self-evident, it demonstrates the importance not only of understanding the adaptive measures found in these historic buildings but also the forces which create (verb needed here) the environmental conditions. Hence, we need to look not only at the phenomena of climate change and its effects on cities but also the counter-measures and associated design process to address new environmental conditions.

As Roaf et al mention, the climate change phenomena in an urban context will mean increases in the temperatures. However, there will also be other effects on environmental conditions. With increase in temperatures an important counter-measure strategy is to examine the influences of the surfaces of urban areas and the impact on outdoor thermal comfort.

The next paper by Alan Lai, Yu Ting Kwok, Minjung Maing and Edward Ng is part of the PLEA Special Edition. The title is ‘Regression modelling of radiant fluxes on different view factors under shading in a densely built environment.’

Conventionally, this has involved examining the radiant environment. This has involved examining solar access to the urban space. Manual methods can be used to provide information on the overshadowing an the urban space by adjacent buildings and vegetation for different times of the year (Szokolay 1996, 20–21). However, in order to understand thermal comfort in the space, it is necessary to collect the mean radiant temperature (MRT) and other environmental factors. Conventionally, this has been done through the use of the global thermometer. However, the authors propose a method, which examines the relationship between MRT and Sky View Factor. The measurement of radiant flux is complex. However, the authors have developed a new model for calculating the mean radiant temperature. The authors report ‘As such, a quick estimation of the potential increase in the outdoor mean radiant temperature in relation to neighbouring built environments can be achieved, and industry guidelines for the design of thermally comfortable open spaces can be formulated accordingly.’ The study is interesting as it disaggregates the elements of urban radiant fluxes into specific factors – Sunlit View Factor (SLVF), Green View Factor (GNVF) and Sky View Factor (SVF). Results show a linear relationship between the factors. Further guidelines are given on the use of adaptive measures to reduce MRT and hence outdoor thermal comfort in the urban tropical environment of Hong Kong. Strategies for reducing radiation from buildings include using biotic elements to shade and cool the urban space from solar radiation.

The next paper called ‘Daytime thermal performance of different urban surfaces: a case study in an institution precinct of Melbourne’ by Salman Shooshtarian and Priyadarsini Rajagopalan is also concerned about the thermal quality of the urban environment. The paper ‘aims to understand thermal behaviour of common urban surface materials in Melbourne's city centre in an educational precinct.’ The authors argue … 

Urbanisation causes changes in the selection of materials, structure and energy balance compared to that in rural areas (Rosenfeld et al. 1998; Coutts, Beringer, and Tapper 2007a). It is well known that modification in the land surface is one of the main contributors to the occurrence of Urban Heat Island (UHI) followed by the anthropogenic heat generation (Asaeda, Ca, and Wake 1996; Solecki et al. 2005). UHI phenomenon is responsible for elevated air temperature (T_a) and surface temperature (T_s) in cities and city centres compared to the surrounding areas.

This study compared the daily and seasonal variations of the near-surface air temperatures of eight common materials including asphalt painted timber, synthetic grass, garden beds, exposed concrete aggregate and granite cobblestone paving. Findings from the research are useful for design decision-making as it suggest which counter measures can assist with reducing local temperature.

The next paper by Maricruz Solera Jimenez is called ‘Green walls: a sustainable approach to climate change, a case study of London.’ It explores the use of vegetation as an adaptive measure to address climate change on the facades of buildings. A monitoring methodology was used to evaluate the performance comparing vegetated walls with non-vegetated walls

The study quantifies and demonstrates that a vegetated façade can reduce the exterior surface temperature by up to 12°C. The results of the case studies demonstrate the LWS can reduce the ambient air temperature between 0.5°C and 4.1°C compared to a distance of 2 m away. Wind speed can be decreased by up to 0.7 m/s in front of a green façade and be reduced to nearly zero into the leaves foliage. The experimental monitoring showed how green walls can provide a cooler ambient temperature and generate fewer temperature fluctuations in London.

Furthermore a survey of users was carried out to study the perceived benefits of the system. The survey demonstrated a positive response amongst interviewees to the system. The main claimed advantages they felt was that the system contributes to the provision of healthy clean air. This leads to the conclusion as to the importance of landscape and microclimate control for climate change migration and adaption counter measures. This can be taken further through using heat mapping of the urban environment and then retrofitting landscape to mitigate the heating effects. Singapore URA has adopted this measure with a Landscape Replacement Policy (2009) (Edward 2018) to achieve this goal.

The next paper by Anir Kumar Upadhyay is called ‘Climate information for building designers: a graphical approach’ and moves the discussion to the design process and to the evolution of climate analysis tools. The study presents current innovative graphical representations of climate data, which it is argued can give designers a more comprehensive view of such data. This paper uses ‘thermal environmental conditions’ as the basis for the analysis of climate data. It then develops design strategies based on the climate information rather than generalized ‘set of recommendations’ found in most of the climate analysis tools.

The paper uses Brisbane as a case study. Putting this paper in perspective, we need to look at how these tools have progressed with the advances in the science. Some of the historical information is found in Docherty and Szokolay 1999 and Szokolay 1996. The development of climate information for architecture came from the development of climate analysis. Doherty and Sokolay argued that whilst early classifications such as Koppen-Geiger, Thornthwaite, which provided data on vegetation and later temperature, rainfall and seasonal variations, were suited to agriculturalists, a simpler system based on the human thermal responses to climate conditions such as comfort was necessary. Hence, they suggested three building-orientated climate types – cold, warm and moderate (which has the attributes of both cold and warm for buildings) and that there are three purposes for climate information;

• (1) to create a qualitative understanding of the climate for human use;

• (2) to provide a basis for simple manual calculations or simple computer programs, and

• (3) to give the climate input for detailed hour by hour simulation programmes.

The purpose of the qualitative data was to represent the climate information in a graphical way to give the characteristic of the climate ‘at a glimpse’ (Docherty and Szokolay, 14). Climate information is also used for determining comfort and uses separate qualitative representations such as the bioclimatic chart with its ‘playful interpretation’ (Auliciems and Szokolay, 1997, 14). The paper starts to rethink the way that climate information is presented using developments in the science of thermal comfort and new techniques of graphic representation.

The next paper presents ‘A study towards interdisciplinary research: a Material-based Integrated Computational Design Model (MICD-m) in architecture’ by Sevil Yazici & Leyla Tanacan.

The main direction of the paper is to present a model which integrates architectural and engineering aspects of design though the medium of computer-aided design. Whilst there have been approaches to design using this methodology this paper brings together the science in both disciplines for schematic work at the conceptual stage in the design process. A custom-designed user interface, database and reports are included in the MICD-m, designed as a plug-in for a 3D geometric modelling tool. The MICD-m is tested with a case study in a parametric modelling environment. The focus on materials in this tool is important since the environmental starting point to the design of many buildings is the decisions concerning the fabric and it is these inherent strengths and weaknesses that draw much of the design attention. An important development work of this tool is the connection to additional software tools that can advance the architectural and environmental understanding and realization of the design.

In the final paper, we turn to environmental quality of internal space. Authored by Mark B. Luther, Peter Horan and Olubukola Tokede it is called ‘Investigating CO2 concentration and occupancy in school classrooms at different stages in their life cycle’.

The move to more active systems in buildings such as schools has meant that the classrooms have become ‘sealed’ which has led to potential problems associated with indoor air quality that may affect the health and well-being of children. Studies of CO2 emissions have been carried out in 24 classrooms in six different schools in Australia. The study found that there are important factors for predicting C02 concentration at different stages in the life cycle of a building from new to 45 years of age. These are the air change rate, carbon dioxide exhalation rate and the number of pupils, respectively. A tool was developed in this paper for on-site evaluation of these parameters to give feedback to the occupants.

News on the changing environments in our worlds’ cities continues to lay down the research agenda for environmental design and urbanization. The Thomson Reuters Foundation recently pointed out … ‘Scorching summer days are growing hotter in the world’'s big cities at a significantly faster pace than the average rise in world temperatures – a trend that could mean more deadly urban heatwaves in years ahead’ (Goering 2018). This article is based on research which draws on data from 9000 weather stations worldwide by the Department of Civil and Environmental Engineering, University of California, Irvine, CA, USA, National Center for Atmospheric Research, Boulder, CO, USA (Papalexiou et al. 2018). They report.

Short-term heatwaves can cause substantial health, economic, and social impacts. They adversely affect animals and plants, and increase the risk of wildfire while inadequate air conditioning may cause human fatalities. Most short-term heatwaves are associated with a strong anticyclone, and often with dry conditions, but they are clearly exacerbated by global warming from human-induced climate change. Other effects, such as intensified urbanization can also add to the risks.

Whilst the conclusion from this research is alarming it gives motivation for more research into softening the impacts of higher-density cites through adaptive measures.

Papalexiou et al. 2018 argue that the research agenda should look at the local causes of temperature increase in the urban setting and developed counter measures to mitigate these effects i.e. think local act local. Papers in this edition provide greater understanding of these issues and offer some counter-measures to the consequences of urbanization. This year’s Architectural Science Association Conference in Melbourne focuses ‘Engaging Architectural Science: Meeting the Challenges of Higher Density.’ (https://www.asa2018conference.com/). The PLEA Conference for 2018 ‘Smart and Healthy within the 2-degree Limit,’ is in Hong Kong (http://www.plea2018.org/) are devoted to the urbanism and climate change.