Analytical and numerical models for estimating the effect of exhaust ventilation on radon entry in houses with basements or crawl spaces

Technical Report · Fri Aug 01 00:00:00 EDT 1986

DOI:https://doi.org/10.2172/5100673· OSTI ID:5100673

Mowris, R J

Mechanical exhaust ventilation systems are being installed in newer, energy-efficient houses and their operation can increase the indoor-outdoor pressure differences that drive soil gas and thus radon entry. This thesis presents simplified models for estimating the pressure driven flow of radon into houses with basements or crawl spaces, due to underpressures induced by indoor-outdoor temperature differences, wind, or exhaust ventilation. A two-dimensional finite difference model is presented and used to calculate the pressure field and soil gas flow rate into a basement situated in soil of uniform permeability. A simplified analytical model is compared to the finite difference model with generally very good agreement. Another simplified model is presented for houses with a crawl space. Literature on radon research is also reviewed to show why pressure driven flow of soil gas is considered to be the major source of radon entry in houses with higher-than-average indoor radon concentrations. Comparisons of measured vs. calculated indoor radon concentrations for a house with a basement showed the simplified basement model underpredicting on average by 25%. For a house with a crawl space the simplified crawl space model overpredicted by 23% when the crawl space vents are open and 48% when the crawl space vents are sealed.

• Research Organization: Univ. of California, Berkeley, CA (United States)
• DOE Contract Number: AC03-76SF00098
• OSTI ID: 5100673
• Report Number(s): LBL-22067; ON: DE87000936
• Resource Relation: Other Information: Thesis. Portions of this document are illegible in microfiche products
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
HOUSES
VENTILATION
RADON
RADIOECOLOGICAL CONCENTRATION
AIR POLLUTION CONTROL
INDOOR AIR POLLUTION
AIR POLLUTION
BUILDINGS
CONTROL
ECOLOGICAL CONCENTRATION
ELEMENTS
FLUIDS
GASES
NONMETALS
POLLUTION
POLLUTION CONTROL
RARE GASES
RESIDENTIAL BUILDINGS
500300* - Environment
Atmospheric- Radioactive Materials Monitoring & Transport- (-1989)