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
| Sep 6, 2012
CPPI awarded $30.3 million contract for University of Florida’s Harrell Medical Education Building
The specialized interdisciplinary learning environment will serve as a focal point for integration and program development for all primary care educational activities in the College of Medicine.
| Sep 5, 2012
Pagano joins Thornton Tomasetti as Vice President in Newark office
Pagano is a Certified Energy Planner and Certified Energy Manager through the Association of Energy Engineers.
| Aug 30, 2012
John S Clark Co. completes teaching lab at UNC Wilmington
Three-story building provides offices, classrooms, and labs.
| Aug 29, 2012
BOND completes South Cove Community Health Center
$11 million, 21,000 square foot community health center opens in Quincy, Mass.
| Aug 29, 2012
Mamayek joins HDR as Design Principal in Boston
He will work closely with the Executive Committee and business group leaders to expand and promote HDR’s Design Excellence initiatives in the Northeast region.
| Aug 28, 2012
McCarthy begins construction on transportation center at Bob Hope Airport
Designed to meet LEED silver certification standards, the facility will feature unique, above ground base isolators that will resist a maximum credible earthquake.
| Aug 28, 2012
Wisnewski Blair & Associates changes name to HGA Mid-Atlantic
New name reflects firm's growing design resources on East Coast.
| Aug 24, 2012
Meis heads to Woods Bagot Sport
Staples Center, Paul Brown Stadium architect to leverage global studio to serve clients worldwide.
| Aug 21, 2012
Under 40 Leadership Summit slated for October 3-5 in Chicago
Attendees will be given an exclusive technical tour of Wrigley Field, led by Steven J. Jacobsen, CDP, who has been retained by the Chicago Cubs to create the business plan and high-level concepts to evaluate the feasibility of various renovation options for this iconic sports venue; and Carl Rice, Cubs’ Vice President, Baseball Operations.