The need to decrease energy usage and subsequent emissions from the building sector has been at the forefront of U.S. green movement. Not only has energy reduction been viewed as a step for improving the environment, it has financial benefits for companies and homeowners.
To address this, researchers at the Massachusetts Institute of Technology’s (MIT) Concrete Sustainability Hub conducted a life-cycle assessment (LCA) study to evaluate and improve the environmental impact and study how the “dual use” aspect of concrete – its ability to offer a durable structure while providing thermal mass benefits for energy loads – affects the environmental footprint of the structure.
"Methods, Impacts, and Opportunities in the Concrete Building Life Cycle" provides a comprehensive analysis that advances three key areas relevant to the buildings LCA field: methodology, benchmarking, and impact-reduction opportunities. The study is a major development for construction-related life-cycle assessment because it thoroughly examines all phases of the complete life cycle of a building – from acquisition of materials to construction, the use of the building, and finally demolition and end of life.
“Most environmental assessments do not move beyond the construction phase and only provide a partial picture of the full impact a particular material can have on a building. This is short-sighted,” David Shepherd, director of sustainable development for the Portland Cement Association (PCA) said. “The heating, cooling, and general operations of buildings and homes in the United States accounts for approximately 70 percent of national energy consumption each year and an accurate LCA needs to include the operational phase.”
Concrete, essential for the construction of buildings and homes, has largely been chosen as a building material for its structural properties rather than its energy-saving properties. Although sustainable builders have known the thermal mass attributes of concrete significantly reduce heating and cooling needs, the energy consumption required to produce its key ingredient, cement, has raised questions about its environmental viability.
In its environmental assessment, MIT researchers found concrete homes produce lower greenhouse gas emissions than current best practice code – compliant wood-frame residences throughout a 60-year service life.
Concrete homes did have a higher embodied global warming potential (GWP) associated with the pre-use phase of LCA when raw materials are harvested and turned into construction materials, transported to the site, and assembled into the finished home. However, this phase accounts for only about 2 to 12%of the overall global warming potential for the life of the home. For the 60-year period of the study, houses constructed with insulated concrete forms have 5 to 8 percent lower GWP than current code compliant light frame wood houses, based on greater thermal mass and higher R-values. Researchers found similar results when evaluating multifamily residences.
Commercial office buildings built with a concrete structural frame produce slightly less greenhouse gas emissions over a 60-year service life than commercial structures built with steel frames, based on the results of the comprehensive MIT assessment.
MIT researchers then evaluated strategies to lower a concrete building’s carbon footprint and overall environmental impact. A major advancement was the incorporation of a cost-impact analysis to determine whether or not a given environmental reduction strategy made economic sense. Among the strategies evaluated, the two that reduced embodied emissions – increased fly ash and reducing the thickness of concrete walls from a 6-inch to a 4-inch concrete core – were found to be both economical and effective ways to reduce emissions. BD+C
Related Stories
Architects | Jan 26, 2016
HOK promotes Bill Hellmuth to chief executive
Hellmuth is set to replace Patrick MacLeamy, who will remain as the firm’s chairman.
Mixed-Use | Jan 25, 2016
SOM unveils renderings of dual-tower Manhattan West development
The five million-sf project includes two office towers, a residential tower, retail space, and a new public square.
Office Buildings | Jan 21, 2016
Nike reveals design, first images of planned 3.2 million-sf expansion to its world headquarters
The expansion looks to combine design elements inspired by human movement, speed, and the strength and energy of competition.
Market Data | Jan 20, 2016
Architecture Billings Index ends year on positive note
While volatility persists, architecture firms reported healthy performance for 2015.
Architects | Jan 18, 2016
EHDD’s Monterey Bay Aquarium wins AIA Twenty-five Year Award
The aquarium set new technical standards for the building type, which still influence today, such as the flow-through seawater-based heat pump system, naturalistic exhibitions, and corrosion protection.
Architects | Jan 15, 2016
Best in Architecture: 18 projects named AIA Institute Honor Award winners
Morphosis' Perot Museum and Studio Gang's WMS Boathouse are among the projects to win AIA's highest honor for architecture.
| Jan 14, 2016
How to succeed with EIFS: exterior insulation and finish systems
This AIA CES Discovery course discusses the six elements of an EIFS wall assembly; common EIFS failures and how to prevent them; and EIFS and sustainability.
Market Data | Jan 13, 2016
Morgan Stanley bucks gloom and doom, thinks U.S. economy has legs through 2020
Strong job growth and dwindling consumer debt give rise to hope.
Architects | Jan 13, 2016
‘Socially engaged’ architect Alejandro Aravena named 2016 Pritzker Architecture Prize Laureate
Known for his inventive social housing initiatives in his native Chile, Aravena epitomizes the revival of a more socially engaged architect, the Pritzker jury stated.
Architects | Jan 12, 2016
Dear Architecture: It's time to create a level field for female designers
If architecture took one moment to be introspective, it would discover appalling imbalances between the opportunities for women and men, as Perkins+Will's Vershaé Hite and Brittany Eaker-Kirkland wrote in an open letter.