MIT Adds Economics to Lifecycle Research on Building Materials

MIT Adds Economics to Lifecycle Research on Building Materials

Researchers at the Massachusetts Institute of Technology are providing an early look at what they describe as groundbreaking work -- the first lifecycle assessments of building and paving materials to consider economic as well as environmental factors and include an in-depth examination of the materials' use phase.

Begun last year and scheduled for completion in 2011, the research will factor in material lifespans that are decades longer than usual -- the lifecycle window being studied for paving materials is 50 years and for building materials, 75 years -- while taking into account a number of variables affecting carbon emissions and cost impacts, said John Ochsendorf, who leads the research team and is an associate professor in MIT’s departments of architecture and civil and environmental engineering.

“We are trying to create a new level of clarity and a new level of literacy about the emissions related to buildings (and roads) and ways to reduce them,” said Ochsendorf.

Generally, costs and environmental impacts such as carbon emissions are considered separately, and analyses tend to emphasize design and construction over aspects such as use, performance and what happens to structures and roads after they’ve reached the end of their useful lives, Ochsendorf said. All those elements are being considered by researchers, he said.

"Absolutely we’re interested in reducing emissions in every phase of lifecycle,” Ochsendorf said. “The really exciting part is in identifying the cost effective opportunities to lower emissions.”

Ochsendorf and the MIT team have set their sights on producing comprehensive studies that establish new standards for lifecycle assessments.

The group also is striving to provide information that can help “develop designs of future that are backed up with the science of LCA,” Ochsendorf said.

Elements being considered by researchers include location, climate and the use phase of buildings and roads, which is a key point in the studies because that is where most emissions occur, Ochsendorf said. Researchers are also comparing use of different materials. The lifecycle assessment for building materials, for example, is expected to show how use of wood, steel and cement can affect environmental impact and cost of a structure. The LCA research is a project of the Concrete Sustainability Hub at MIT, a research center established in 2009 in collaboration with the Portland Cement Association and Ready Mixed Concrete Research & Education Foundation.

Early research findings, which were released last week, show that more than 90 percent of carbon emissions of a residential building and as much as 85 percent of emissions from highway pavement occur during the use period.

Other preliminary findings include:

  • In comparing use of concrete and steel in 12-story commercial buildings in warm and cold climates, research indicated that the thermal mass provided by concrete results in HVAC energy savings of 5 to 6 percent.
  • In comparing use of insulated concrete forms and wood frames in residential, research indicated the potential of operational energy savings of 20 percent and or more, with the greatest savings occurring colder climates.

 

In their studies, the researchers are using composites of buildings and highways and layering on data and variables to conduct the environmental and cost analyses, Ochsendorf said. For the buildings portion, the researchers started with 16 benchmark building models, which were developed by the Department of Energy and three of its national laboratories. The roads portion initially draws information from the California Department of Transportation and other highway agencies.

More information about the research is available at MIT’s Concrete Sustainability Hub and www.whataretherealcosts.org/index.html.

 

Image CC licensed by Flickr user Mike McCaffrey.