Perspectives on Sustainability

The connection between sustainable architecture and architectural science is implicit in the work that is being done around the world and here in Canada. That is why this first contribution to Architectural Science Forum begins with perspectives on sustainability–to outline the science and technology behind sustainable architecture.

Architectural science, commonly referred to as building science, is a composite body of knowledge, borrowing from the physical, life and social sciences within the context of architectural practice and education. It informs decisions across a wide range of design considerations from siting, to building systems, to the health and well-being of occupants. In some areas, where research and practice have advanced, this knowledge supports predictive methods of design and analysis. In other areas it informs us about relationships between nature and buildings, and points to future directions of exploration and initiative. It is recognized that architectural science represents only a part of the spectrum of knowledge associated with sustainable architecture, but this does not diminish its relevance to evolving architectural practice.

Sustainability Defined

Sustainability has many dimensions. It is not possible to deal with all of them here. For the purposes of this article, a broad consensus definition is presented as the basis for further discussion:

Humanity has the ability to make development sustainable–to ensure that it meets the needs of the present without compromising the ability of future generations to meet their own needs. The concept of sustainable development does imply limits–not absolute limits but limitations imposed by the present state of technology and social organization on environmental resources and by the ability of the biosphere to absorb the effects of human activity.

— G.H. Brundtland (Chair), Our Common Future, World Commission on Environment and Development, Oxford University Press, New York, 1987.

This definition implies that sustainability is not an architectural problem specifically, but rather a global cultural problem to which architecture may contribute valuable solutions. Architects and allied practitioners have acknowledged this role for some time now. Nearly 100 member countries of the Union Internationale des Architectes (UIA) signed the following declaration at the UIA/AIA World Congress of Architects in Chicago on June 21, 1993.

Architectural Science and Sustainability

Modern architectural science addresses the technological dimensions of sustainable architecture. It provides insight into the state of building technology and the ability of the biosphere to absorb human activities and interventions. We now know, with a high degree of confidence, that buildings, their construction, operation, maintenance, repair and deconstruction contribute significantly to climate change, the depletion of natural resources and degradation of the environment, including reductions in biodiversity. This awareness has spawned initiatives such as Canada’s National Standard for Sustainable Forest Management (CAN/CSA Z-809), but the impact of building materials production addresses only part of the problem.

Buildings account for almost one third of Canada’s annual, non-renewable energy consumption and greenhouse gas (GHG) emissions. Based on the evidence (see table), the buildings sector has had differential success in addressing Canada’s commitment to the Kyoto Agreement, which requires reductions to six per cent below 1990 GHG emission levels between 2008-2012. Government investments in residential buildings research and development since the 1980s, through a variety of energy efficiency and technology transfer programs, have yielded impressive returns in terms of avoided energy use and reduced GHG emissions. In the residential sector, without the last decade of improvements in codes, standards and practices, today’s GHG emissions would have been at least nine megatonnes higher, representing a 13.2% increase over 1990 levels. By contrast, in the commercial sector, the ubiquity of air conditioning coupled with the increasing intensity of computer use in offices, has resulted in a 13.7% growth in GHG emissions since 1990.

These statistics may appear gloomy, but important information is missing. The data apply to the entire building stock in Canada, from centuries-old buildings to the latest designs. Below the contemporary tip of Canada’s building stock iceberg await billions of square metres of building retrofit opportunities. Running parallel to the life cycle of Canada’s building stock are several positive trends. First, the energy efficiency of virtually all equipment, appliances and fixtures is constantly improving, and the potential for improvement is huge. (For example, the exergy efficiency, or absolute energy efficiency, of artificial lighting is a scant 0.8% at best; the other 99.2% of the electrical energy produces heat and light outside the spectrum visible to the human eye.) Second, investments in renewable energy sources will gradually replace non-renewable energy use, as its availability, cost and environmental impacts escalate. Significant contributions to sustainable development are within grasp, provided the knowledge needed to implement appropriate building technologies is available and accessible.

At present, the vast majority of architectural science research and development takes place with little input from, and even less direct participation by, architects. Design aesthetics are visible and accessible, whereas the sustainability dimensions of architecture remain implicit. This explains, in part, the interest in didactic “green” buildings where what happens after you flush the toilet is on display as a substitute for improved public awareness and education about architecture and the built environment. Unfortunately, the environmental impacts of buildings are not always so easy to portray because electricity, heat and greenhouse gases are largely invisible, as are many of the related side effects (externalities), affecting environments far beyond the property line. The architectural design process, let alone architectural science, remains equally mysterious to the average person.

Back to the Future?

In many ways, the continuing advances in architectural science are making it possible to become as connected to our environment, and as aware of our ecological impacts, as were the indigenous peoples of the past. It is now possible to make very reliable assessments of environmental consequences over the life cycle of a building.

At the design stage, a wide array of tools is now available to the practitioner, and emerging computer applications will soon enable the modeling and dynamic simulation of entire building system performance. Some advanced tools include: hygrothermal analysis of building envelope assemblies in response to heat, air and moisture flows; computational fluid dynamics (CFDs) applied to passive and active environmental systems behaviour; indoor air quality prediction and assessment models; acoustical and lighting design packages–not to mention applications in geotechnical, structural and aerodynamic engineering.

Predictive models and data are now a natural by-product of the computer aided design process. These can be applied to derive scientifically sound measures of sustainability, such as embodied energy, operating energy, exergy (absolute energy efficiency), durability, externalities, and ecological footprint. Further, these simpler measures can be combined into composite measures of sustainability obtained from life cycle assessment (LCA) techniques that more fully consider environmental impacts associated with architectural interventions.

The future of sustainability lies in public education and will be reinforced through the eco-labeling of products, materials and buildings. In Canada, labeling programs such as EnerGuide for Houses and the BREEAM/ Green Leaf Eco-Rating Program represent consumer-friendly measures of environmental responsibility that are gaining in use and acceptance. It is import
ant that architects acquire the knowledge needed to understand and contribute to these developments.

Obstacles and Opportunities

Sustainability is posing significant challenges to architects and allied professions. Heightened and often conflicting expectations by owners and occupants for economical and healthful buildings continue to strain conventional building budgets. Keeping up with advances in computer aided design technologies and information systems now demands an ongoing allocation of resources in progressive practices. The rate of innovation in building materials and systems continues to escalate, increasing the need for a more rigorous education and career development process. It seems that just as the sustainability of architecture as a profession is being tested, the demands for sustainable architecture further stress what is already a complex and demanding discipline.

Lack of public awareness and unwillingness to pay represent major obstacles to sustainable architecture, which generally costs more to design and build. Life cycle concepts are not well understood and continue to hold little interest for building owners. Sustainable architecture is a knowledge-based activity that challenges traditional buildings, their construction costs and design fees.

Immense opportunities are waiting to overcome the cultural inertia resisting sustainable architecture, and most of them will involve the application of architectural science. Bio-climatic approaches to design are demonstrating the potential to greatly reduce, and, in some climates, entirely eliminate non-renewable energy demands for environmental control. The art and science of daylighting and natural ventilation are being revived to address the health and well-being of urban populations that spend up to 90% of their time indoors. Innovative designs for flexible, adaptive architecture incorporating durable materials and components not only extend the service life of buildings, but also their social utility, providing more stable rates of return on building investments. A host of bio-technologies which benignly manage runoff, water and waste, in concert with renewable energy sources, nurture intensification and de-centralized communities. From an architectural science perspective, never has modern design freedom been greater. It is hoped the sensitive articulation of functional form and the intelligent integration of systems demanded by sustainable architecture will inform, rather than discourage, architectural expression.

This discussion of perspectives on sustainability is intended to reinforce the idea behind Architectural Science Forum. As architecture more fully engages the challenge of sustainable development, the need for architectural science education and the free exchange of knowledge will gain importance.

Ted Kesik is a professor in the Department of Architectural Science at Ryerson University and Visiting Associate Professor in the Faculty of Architecture, Landscape and Design at the University of Toronto. The full electronic version of this article is available on the Web at under Architectural Science Forum. This forum is intended to facilitate the exchange of knowledge and information pertaining to architectural science among practitioners, researchers, academics and students of architecture and its allied disciplines. For further information on submissions to Architectural Science Forum, contact:

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Above: table showing trends in energy consumption and greenhouse gas emissions in Canada, 1990 to 1999. (Source: Energy Efficiency Trends in Canada 1990 to 1999–An Update, Natural Resources Canada, Ottawa, 2001.)

UIA Declaration of Interdependence for a Sustainable Future

We commit ourselves, as members of the world’s architectural and building-design professions, individually and through our professional organizations, to:

Place environmental and social sustainability at the core of our practices and professional responsibilities;

Develop and continually improve practices, procedures, products, curricula, services, and standards that will enable the implementation of sustainable design;

Educate our fellow professionals, the building industry, clients, students, and the general public about the critical importance and substantial opportunities of sustainable design;

Establish policies, regulations, and practices in government and business that ensure sustainable design becomes normal practice;

Bring all existing and future elements of the built environment–in their design, production, use, and eventual reuse–up to sustainable design standards.