During the past 10 years the U.S. Environmental Protection Agency (EPA) has pursued a national strategy to address radon remediation in buildings to meet its goals of radon risk reduction. Initially the approach developed and demonstrated remediation methods and techniques in existing residences with specific attention to the effect of regional climate variations and the differences in housing construction. A number of studies and demonstrations were undertaken to accurately characterize and evaluate the effectiveness of several remediation methods and techniques.
A computational sensitivity analysis was conducted to identify the conditions under which residential active soil depressurization (ASD) systems for indoor radon reduction might most likely exacerbate or create back-drafting of natural-draft combustion appliances. Parameters varied included: house size; normalized leakage area; exhaust rate of exhaust appliances other than the ASD system; and the amount of house air exhausted by the ASD system.
The effects of cracks and holes on the exhalation of radon from concrete have been investigated. It was found that the total radon exhaled from concrete blocks was the same irrespective of the diameters of holes drilled into them, and irrespective of the number of holes drilled. Furthermore, the surface area of the concrete blocks did not have any effect on the total radon exhaled
This report is one of a series giving practical advice on methods of reducing radon levels in existing dwellings. It is intended to help surveyors, builders and householders who are trying to reduce indoor radon levels by positive pressurisation. The report is based on a large body of remedial work carried out to advice from the Building Research Establishment (BRE), and on discussions with others working in the field. The measures it describes are applicable, in principle, to all dwellings and similar buildings.
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