Air and Pollutant Transport from Attached Garages to
Residential Living Spaces – Literature Review and Field Tests
S.J.
Emmerich, J.E. Gorfain and C. Howard-Reed
National Institute of Standards and Technology, Gaithersburg, MD
20899 USA
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Abstract
The National Institute of Standards and Technology
(NIST) is conducting a study on the indoor air quality (IAQ) impacts and
engineering solutions related to the transport of pollutants from attached
garages to residential living spaces.
Natural or fan-induced pressure differences across air leakage
paths in house-garage (HG) interfaces can result in the transport of the
contaminants generated in garages into adjacent living spaces. This
paper summarises a literature review on the transport of pollutants from
garages to residential living spaces and describes a field study to
estimate the range of airtightness of attached garages and of HG
interfaces in the United States.
Although the body of literature on pollutant
transport from attached garages to residential buildings is limited, the
studies reviewed provide substantial evidence that transport of
contaminants from garages has the potential to negatively impact
residential IAQ in either an acute (e.g., carbon monoxide from
automobiles) or chronic manner (e.g., storage of chemical products).
However, the literature contains few answers on issues such as the
airtightness and geometry of the HG interface, the impact of heating and
cooling equipment in the garage, and the effectiveness of potential
engineering solutions.
To address one gap in understanding these issues, the airtightness of
garages and HG interfaces was measured in five residences using fan
pressurisation. While the small sample of houses limits generalisation of
the results, a range of house ages, styles, and sizes was included. For
all homes tested, the garage was found to be at least twice as leaky as
the house, based on air change per hour at 50 Pa. The
leakiness of the garage envelope, based on surface area normalised
effective leakage area at 4 Pa (ELA4/SA), ranges from a high of
nearly eleven times to a low of two and a half times that of the house
exterior envelope leakage. On average, the HG interface was almost two and
a half times as leaky as the rest of the house envelope, when based on ELA4/SA.
However, this average is somewhat skewed due to one HG interface measured
in this study that is almost eleven times as leaky as the rest of the
house envelope. Conversely, a larger Canadian study found HG interfaces to
be comparable to house envelopes but found the average garage to be about
ten times as leaky as houses – possibly because Canadian houses are
consistently tighter than U.S. houses (Fugler et al. 2002).
The knowledge gained from this review and the field study will be used in
a simulation study of the potential occupant exposure to pollutants from
attached garages and to explore potential engineering solutions to this
IAQ problem.
Key words: house-garage interface, attached
garage, blower door, indoor air quality, living space, pollutant
transport, airtightness.
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