THE IMPORTANT ROLE OF LIFE-CYCLE ASSESSMENT

Building greener communities begins with being able to measure the environmental impacts of our buildings, roads and other infrastructure projects so that they can be minimized.

A growing number of decision makers rely on a Lifecycle Assessment (LCA) approach to design, build and maintain buildings and infrastructure with a significantly lower carbon footprint.

LCAs seek to measure the environmental impacts associated with all stages of a product (e.g. concrete) or a project (e.g. a building or highway), from raw material extraction through to processing, transportation, use and disposal.

For example, LCA studies have shown that depending on location and service life, over 90% of our buildings’ emissions come from operational energy use. Similarly, multiple studies have shown that the environmental impact of the 'in use' phase of our highways and roads outweigh all other phases of a pavement’s lifecycle, including construction.

A new landmark study done by the International Institute for Sustainable Development (IISD), Emission Omissions: Carbon accounting gaps in the built environment, finds that life-cycle assessment (LCA) is the right approach to measure carbon emissions, but more data, transparency and robust LCA standards are needed, especially with respect to accounting for biogenic carbon from wood products.

According to the researchers, LCAs need to become more robust and transparent, including full disclosure of research assumptions, if they are to guide GHG reduction strategies and reduce other environmental harms from buildings and infrastructure.

CONCRETE’S PERFORMANCE OVER THE LIFE-CYCLE

The Canadian concrete industry has been working with experts from MIT, the Athena Sustainable Materials Institute and the International Institute for Sustainable Development to identify and measure concrete’s contribution to the sustainability performance of our buildings and infrastructure projects.

MIT studies show that the passive energy efficiency of concrete’s thermal mass — gains of 8% over other building materials — more than make up for the embodied impacts of the cement and concrete manufacturing process. Used strategically and integrated with smart design and technologies, concrete’s thermal mass reduces the operational energy needs of large commercial buildings. Such an example is Manitoba Hydro Place (MHP), which has achieved a 70% energy efficiency improvement over the Model National Energy Code for Buildings.

The new peer-reviewed study Emission Omissions: Carbon accounting gaps in the built environment, conducted by the International Institute for Sustainable Development finds that up to 72% of a wood product’s carbon emissions may currently be omitted from wood LCAs and that when these emissions are taken into account, concrete’s embodied carbon footprint could be up to 6% less intensive than that of wood products.