April 15, 2007

Model Homes Offer National IAQ Impact Results

Airborne contaminants in homes can range from allergic agents such as mold to potentially lethal threats such as carbon monoxide. Engineers at the National Institute of Standards and Technology (NIST) have developed a database of U.S. residential housing* to help conduct nationwide analyses of ventilation, air cleaning or moisture control strategies to reduce indoor air pollution.

Most people presume that the indoor air quality (IAQ) measures that rid one house of airborne contaminants should work in a similar house, but when it comes to ranking, on a regional or national scale, potentially expensive residential code or construction changes, housing and health authorities as well as homebuilders want more than conventional wisdom and supposition. They want data, and a lot of it. The new NIST set of more than 200 residential dwellings, representing 80 percent of the United States housing stock, can be combined with a computer simulation technique to determine the impacts of IAQ interventions.

NIST developed its database of model homes from the U.S. Census Bureau's American Housing Survey (AHS) and the U.S. Department of Energy's (DOE) Residential Energy Consumption Survey (RSECS). They then selected 209 dwellings as representative of 80 percent of U.S. housing stock. The homes, grouped into four categories--detached, attached, manufactured homes and apartments, were defined by their age, floor area, number of floors, foundation type and existence of a garage.

The engineers then developed floor plans for each house and created a model of each in NIST's multizone indoor air quality and ventilation assessment computer program, CONTAM. Analysts can use the models to simulate and examine energy, IAQ and human exposure issues in a particular type of dwelling or all the dwellings as a group. Conclusions drawn from simulations with a particular house type should be valid for similar houses on a nationwide or regional level. The current multizone representations of the 209 dwellings created with CONTAM are available at http://www.bfrl.nist.gov/IAQanalysis along with floorplans of the buildings. The U.S. Department of Housing and Urban Development sponsored this work.

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*A. Persily, A. Musser and D. Leber. A collection of homes to represent the U.S. housing stock. NISTIR 7330, August 2006.

Contact: John Blair
National Institute of Standards and Technology (NIST)

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