Growing up: What’s next for building life cycle assessments?

Life cycle assessments (LCA) are becoming increasingly sophisticated. How will they evolve to help us better measure — and minimize — the environmental impacts of our buildings?

Our Intelligent Infrastructure series explored numerous aspects of the technologies that are, or will be, integrated into our built environment and daily lives. But technologies, important as they are, are not the only tools to make a building smart.

While technology is the origin of the smart concept and remains an integral aspect, the definition of smart buildings is evolving to encompass all factors that make a building more effective, liveable and sustainable. How we define a smart building can include not only the tech, but also the design strategies to achieve sustainable and positive outcomes. Regulating bodies, rating systems, builders and consumers continue to ask: what can be done to maximize a building’s sustainability and minimize its environmental impact? To answer this question, we need to actually know the environmental impact of our buildings, both now and in the future — we need a whole-building Life Cycle Assessment (LCA).

 

Life cycle assessment (LCA)

Broadly, LCA is a method to measure the holistic impact that a product or process has on the environment. The methodology looks at the full lifespan and the full inventory of a product’s parts. In a buildings context, LCA can be a powerful decision-making and reporting tool for design teams and building owners alike, offering a broad and meaningful set of metrics and helping to answer key questions about the impacts of energy and materials, on-site processes and procurement.

LCA can ask and answer questions like: what is the optimal amount of insulation? What materials can be best re-used at their end-of-life? Is it better to source a material with higher recycled content from farther away, or a local material with lower recycled content?

Life cycle assessments as environmental management tools emerged in the 1960s, and have been widely used in the building sector since 1990. However, the comprehensive framework employed today, which includes International Organization for Standardization (ISO) standards, has only evolved within the past five to 10 years — largely due to changes in the Leadership in Energy and Environmental Design (LEED) certification program. Under LEED, LCA has been pushed more deeply into the psyche of building developers and regulators. But with the growing impetus for holistic and smart approaches, how will LCA respond and evolve?

 

The future of LCA

Tracking embodied and operational impacts

There are two broad categories for a building’s impact on the environment:

  1. Operational impacts: those which result from operating the building moment-to-moment (e.g., due to energy used by equipment)
  2. Embodied impacts: those which are emitted in the manufacturing, maintenance and eventual disposal of building materials (e.g., due to the construction of structural systems).

As we get a handle on optimizing operational performance, which has historically been the predominant focus of building sustainability, the applicability of LCA as a tool in tracking and minimizing the embodied impacts of a building has become increasingly important. Focus on embodied impacts has increased as electricity grids in places such as British Columbia, Ontario and Quebec have transitioned to low-carbon sources — and thus, opportunities for emission reductions from these already-clean grids are lower. LCA can track and provide insights to optimize embodied impacts while also considering operational impacts.

Building lifecycle-EN

Operational and embodied impacts of a building through its lifecycle

 

Tracking carbon

Following the Paris Agreement (2016) and subsequent efforts to reduce carbon emissions around the world, there has been a shift in focus from energy to carbon reduction. LCAs are used to track the full range of impacts on the environment, of which carbon or Greenhouse Gas Emissions (GHGs) are the established metric for measuring global warming and climate change impacts. LCAs can track baseline whole-life carbon footprints and carbon hotspots throughout the entire development, thereby identifying opportunities for GHG reduction.

 

Improving technology — modeling and blockchain

With the growth of LCA, a variety of software platforms have been developed to serve the growing market. Software such as Athena Impact Estimator, Tally, SimaPro, and GaBi can be used to create a building LCA model that considers where materials come from, how they are manufactured, where and how they are transported, and how the building is constructed on site. The model then tallies the impacts of the steps in each material’s life cycle to calculate the building’s cumulative life cycle impact. Design decisions can be informed by looking at a whole building model, or by examining relative impacts for specific materials. For example, comparisons can be made to clearly determine the environmental advantages of pursuing a wood versus concrete structure for a high-rise building, or vice versa.

Blockchain technology also offers opportunities for increased accuracy in LCA results, making the fine-tuned, bottom-up details about a product’s lifecycle available to practitioners. Briefly and simply, blockchain is a technology that accrues and stores digital information (“blocks”) in a public digital ledger (the “chain”). This publicly available ledger of accumulated information facilitates project-specific detail in an LCA, including precise greenhouse gas and energy-use footprints, which would otherwise be too detailed to track, thereby increasing the accuracy of LCA results and improving supply chain transparency and legitimacy.

 

Increasing adoption — voluntary and mandatory

Sustainability rating systems for the built environment, such as BREEAM, LEED, and Envision, have begun rewarding projects that put in the effort to examine extended building impacts with LCA. For example, BREEAM has outlined mandatory LCA assessments of embodied carbon impacts in its New Construction Scheme (2018). LEED’s most recent version (V4) of their green building rating strategy includes the inaugural introduction of whole-building LCA optimization, including a required 10 per cent reduction in embodied carbon from a project-specific baseline.

In addition to gaining widespread momentum organically, in some cases, LCA adoption is formally required. At the time of publication, one of the only examples in Canada is the City of Vancouver’s newest Green Buildings Policy for Rezonings, which now requires whole-building embodied carbon emissions reporting (using LCA) at three project permitting milestones.

As LCA-based tracking and reporting becomes more common, it is likely that datasets will be used to inform further policy - specifically, mandated reductions in embodied carbon intensity. At the time of publication, there are no known policies for mandatory reductions in embodied carbon in Canada; however, the City of Vancouver has publicly stated that following building impact disclosures, reductions to embodied carbon may be introduced, first in voluntary incentive-based programs and later as requirements.

 

Improving strategy

As the LCA perspective becomes increasingly refined and integrated into owner expectations, regulations and guidelines, design and assessment strategies need to evolve and be adopted early in the design and construction process to enable more effective decision-making. Well-structured teams, with a specialized LCA consultant (who often also wears the hat of the energy modeller or sustainability consultant) and early buy-in from the architectural, envelope, and structural consultants, will realize the many benefits and savings in GHG mitigation and other environmental impacts.

As building LCA concepts, methods and regulations mature, we gain more than just a comprehensive inventory of the sum of the parts. In addition to exploring a building’s environmental footprint more holistically, we also gain a foundation for effective action to reduce environmental impacts and develop insights to build even smarter buildings.

Authors

Antoni Paleshi
Project Director, Buildings
Canada
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Jamie Summers
Program Consultant, Future Ready
Canada
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