Putting lifecycle performance at the centre of sustainable communities
Our built environment is at the heart of sustainability – the source of, and potential solution to virtually every sustainability challenge we face. How we design and build our communities and the buildings they contain
has vast implications for energy use, transportation, water and wastewater management, food supply and distribution, our social and economic prosperity and health, as well as our safety, security and resilience in the face of natural and human-made disasters.
it's no surprise, and indeed in many ways a great comfort, that cities − their planners, architects, engineers, asset managers, politicians and others − are at the forefront of sustainable innovation. through initiatives such as architecture 2030 and, of course, leed v4, new perspectives and new tools are reshaping the conversation about built infrastructure and the role that it can play in realizing a sustainable and resilient future.
perhaps one of the most important tools to benefit from this attention on the sustainability of our built environment is life cycle assessment (LCA). LCA recognizes the complexity hidden behind sometimes deceptively simple questions about the sustainability of a product or service by examining all stages of its life, from “cradle-to-cradle” – i.e. raw material extraction through materials processing, manufacturing, distribution, use, repair and maintenance, and end of life (repurposing, reusing, recycling or disposal). LCAs are underpinning greater transparency in the marketplace through, for example, facilitating the development of environmental and health product declarations (EPDs and HPDs), now recognized in leed v4. they add rigor and credibility to the claims of product manufacturers about the impacts of their products and services.
at the same time, LCAs are not without limitations, particularly when attempting to assemble a picture of sustainability for complex systems like buildings. in the same way that the whole isn't always the sum of
its parts, LCAs for individual products cannot be aggregated to give you a simple measure of a building's overall sustainability. taking greenhouse gas emissions as one example, buildings are responsible for up to half of all emissions in Canada and the u.s. and, depending on the location and service life, well over 90% of these emissions come from operational energy use. optimizing building performance is clearly a critical piece of solving the climate change challenge, which makes it all the more critical that we deploy LCAs at the systems level to give us an integrated picture of how all the components of a building – design, materials, technologies etc. – work together to optimize performance.
the Canadian concrete industry has taken this kind of approach, working with experts from MIT, the Athena sustainable materials institute, the university of British Columbia, the university of Toronto, the university of Waterloo and other Canadian institution, to identify and measure what concrete contributes to the life cycle sustainability performance of buildings, roads, and other infrastructure projects. in virtually all cases, and especially for buildings, LCAs demonstrate how architects and other infrastructure professionals can leverage
tremendous sustainability performance improvements through integrative approaches to materials and design.
for example, multiple academic studies illustrate that the passive energy efficiency benefits of concrete and masonry's thermal mass – gains of up to 8% over other materials – typically more than make up for the embodied impacts of the cement and concrete manufacturing process. more importantly, integrating thermal mass as a design strategy and pairing it with passive and/or active radiant heating and cooling systems can magnify efficiency benefits by a factor of ten while offering “side benefits” for indoor air quality and occupant health,
safety, comfort and productivity.
as we think to the future of green building, a key indicator of progress will surely be the extent to which the transparency offered by LCAs and other predictive measurement tools is translated at the project level to leverage
synergies between design, materials and technology and enhance the lifecycle sustainability performance of our buildings and communities.
Finally, longevity played a large role, highlighting how one of concrete's key advantages − durability from wind-driven rain, and other forms of environmental degradation – leads to lower maintenance, longer service-life
structures that extract the best economic and sustainability value from the cost, energy and materials required to build them.
Modeling the energy efficiency benefits of the concrete's thermal mass was not part of the original study, however, the design of the building takes full advantage of this property; the result is a LEED Platinum building that
uses over 40% less energy than an equivalent conventional building. While performance data is still being collected and analysed, preliminary results suggest that per unit of floor area, Équiterre may have realised their goal
of becoming the most energy efficient office building in Canada.
Source: Rediscover Concrete by CONCRETE COUNCIL OF CANADA.