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 16, 2013
Forty-three percent of energy leaders will invest more in efficiency next year (infographic)
Forty-three percent of energy leaders say their investment in energy efficiency next year is projected to be more than it was last year, according to survey results released today by Schneider Electric. Twenty-two percent said their projected investment would stay the same, and 10 percent reported their investment would be less than last year.
| Sep 16, 2013
Forty-three percent of energy leaders will invest more in efficiency next year (infographic)
Forty-three percent of energy leaders say their investment in energy efficiency next year is projected to be more than it was last year, according to survey results released today by Schneider Electric. Twenty-two percent said their projected investment would stay the same, and 10 percent reported their investment would be less than last year.
| Sep 16, 2013
Construction spending hits four-year high in July: AGC report
Total construction spending hit a four-year high in July as private residential and nonresidential activity increased while public spending declined, according to an analysis of new Census Bureau data by the Associated General Contractors of America. Association officials urged lawmakers in Washington to make infrastructure investment a top federal priority before funding runs out at the end of September.
| Sep 13, 2013
Loews Hotels & Resorts announces major cross-portfolio upgrades
Loews Hotels & Resorts is currently in the midst of a major growth and property redesign initiative, reflecting a strong national trend in hospitality renovation.
| Sep 13, 2013
Video: Arup offers tour of world's first algae-powered building
Dubbed BIQ house, the building features a bright green façade consisting of hollow glass panels filled with algae and water.
| Sep 11, 2013
Inaugural BUILDINGChicago/Greening the Heartland Expo & Conference draws attendees from 27 states
More than 500 attendees from 27 states attended the inaugural BUILDINGChicago/Greening the Heartland Conference, held September 9-11, at the Holiday Inn Chicago Mart Plaza.
| Sep 10, 2013
The new medical office building: 7 things to know about today’s outpatient clinic
Regulatory pressures, economic constraints, and emerging technologies are transforming healthcare. Learn how Building Teams are responding with efficient, appealing, boundary-blurring outpatient buildings.
| Sep 6, 2013
Public Architecture's Day Labor Station: Just the type of 'great idea' we're looking for in the $5,000 Vision U40 competition
Thinking about competing in BD+C's Vision U40 program at next month's U40 Leadership Summit? Here's a good example of the kind of "great idea" we're looking for.
| Sep 6, 2013
U40 Summit featured speaker: Arthur Gensler on how to build a world-class AEC practice
Gensler, founder of the world’s largest architecture firm, will talk about the role of the architect in society, the impact of great design, and the practicalities of starting and running a practice, and will offer advice for today’s young design and construction professionals.
| Sep 4, 2013
Augmented reality: 12 applications for design and construction professionals
Building Design+Construction reached out to AEC professionals who have studied and applied augmented reality and asked them to pinpoint applications that are ripe for the technology. Here’s what they had to offer.