The report describes analytical procedures for diagnosing radon entry mechanisms into buildings. These diagnostic methods are generally based on the premise that pressure-driven flow of radon-bearing soil gas into buildings is the most significant source of radon in houses with elevated concentrations, although procedures to determine the contributions of other potential sources to indoor airborne concentrations are also included. The initial problem assessment procedures rely on an organized set of measurements to characterize the structure, the surrounding soil, and the likely entry pathways from the soil into the building. The measurement procedures, described in detail, include radon grab sampling under both naturally and mechanically depressurized conditions, visual and instrumental analyses of air movement at various substructure locations, building leakage area tests, and soil characterization methods. Post-mitigation evaluation procedures are also described. Samples of various data forms and test logs are provided.

"June 1988." "EPA/600/8-88/084." Microfiche.