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 24, 2014
Architecture billings see continued strength, led by institutional sector
On the heels of recording its strongest pace of growth since 2007, there continues to be an increasing level of demand for design services signaled in the latest Architecture Billings Index.
| Sep 24, 2014
Frank Gehry's first building in Latin America will host grand opening on Oct. 2
Gehry's design for the Biomuseo, or Museum of Biodiversity, draws inspiration from the site's natural and cultural surroundings, including local Panamaian tin roofs.
| Sep 23, 2014
Cedars-Sinai looks to streamline trauma care with first-of-its-kind OR360 simulation space
The breakthrough simulation center features moveable walls and a modular ceiling grid that allow doctors and military personnel to easily reconfigure the shape and size of the space.
| Sep 23, 2014
Third phase of New York’s High Line redevelopment opens
The $35 million Phase 3, known as High Line at the Rail Yards, broke ground September 20, 2012, and officially opened to the public on September 21.
| Sep 23, 2014
Cloud-shaped skyscraper complex wins Shenzhen Bay Super City design competition
Forget the cubist, clinical, glass and concrete jungle of today's financial districts. Shenzhen's new plan features a complex of cloud-shaped skyscrapers connected to one another with sloping bridges.
| Sep 23, 2014
Designing with Water: Report analyzes ways coastal cities can cope with flooding
The report contains 12 case studies of cities around the world that have applied advanced flood management techniques.
| Sep 22, 2014
4 keys to effective post-occupancy evaluations
Perkins+Will's Janice Barnes covers the four steps that designers should take to create POEs that provide design direction and measure design effectiveness.
| Sep 22, 2014
NCARB overhauls Intern Development Program, cuts years off licensure process
The newly adopted changes will be implemented in two phases. The first will streamline the program by focusing on the IDP’s core requirements and removing its elective requirements. The second phase will condense the 17 current experience areas into six practice-based categories.
| Sep 22, 2014
Biloxi’s new Maritime and Seafood Industry Museum is like a ship in a bottle
Nine years after the Museum of Maritime and Seafood Industry in Biloxi, Miss., was damaged by Hurricane Katrina’s 30-foot tidal surge, the museum reopened its doors in a brand new, H3-designed building.
| Sep 22, 2014
Swanke-designed Eurasia Tower opens in Moscow
The 72-story tower—the first mixed-use, steel tower in Russia—is located within the new, 30 million-sf, 148-acre Moscow International Business Center.