Evaluation of Radon-Resistant Construction Techniques and Radon Measurement Methods
Creators: name: Cseko, Gary Carl
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 1998

description: This research project included two main objectives. The primary objective was to evaluate the effectiveness of radon-resistant home construction techniques in Zone 1 counties of North Carolina. Zone 1 counties have an average predicted indoor radon screening potential greater than 4 pCi/L[-1](US EPA 1993). The secondary objective was to evaluate the commercial charcoal radon test kits used for the home radon measurements. The commercial kits were compared with charcoal diffusion barrier canisters made at The University of North Carolina at Chapel Hill and a Pylon Model AB-5 Radon Monitor. The commercial kits and two types of UNC diffusion barrier charcoal canisters were evaluated under "field conditions" in a laboratory at UNC. The materials used for the diffusion barriers included glass fiber and stainless steel. Experiments were performed in which several of each type of UNC diffusion barrier canister and commercial charcoal kits were exposed to varying radon concentrations for periods of 4 or 7 days, analyzed, and the results compared to those determined by a Pylon continuous direct reading radon monitor. The diffusion barrier canisters and commercial kits all seemed to give average concentrations that were closer to the average Pylon results for the last 1-3 days of the exposure period than the average for the entire exposure period. It was concluded that all charcoal detectors evaluated were more sensitive to concentrations near the end of deployment. The results of this study also indicated better precision of measurement for the commercial kits than for the UNC diffusion barrier canisters. To identify homes equipped with radon-resistant construction, advertisements offering free radon testing were placed in select newspapers in Western North Carolina. Once homeowners were identified, commercial radon test kits were mailed to each participant and they were asked to complete a questionnaire regarding the construction of their home. Analyses of the test kits were performed by the manufacturer which participates in the EPA's Radon Measurement Proficiency Program. Radon concentrations measured in the homes were compared with the EPA guideline of 4 pCi/L as well as results from a radon survey conducted in 1990 by the EPA and North Carolina Division of Radiation Protection (NCDRP). All Buncombe county homes tested in the UNC study, which featured a vented sub-slab system, had basement radon concentrations less than the EPA guideline of 4 pCi/L. The average basement radon concentration for these homes was 1.9 pCi/L, which is less than the average determined by the EPA/NCDRP study for Buncombe county (2.18 pCi/L). The average basement concentration for Buncombe county homes with radon-resistant construction, other than vented sub-slabs, is 6.9 pCi/L, which is higher than the EPA/NCDRP study average. These data, while limited, suggest that vented sub-slab systems are an effective radon-resistant construction technique. Only sixty-six percent of Watauga county homes tested, which featured a vented sub-slab system, had basement concentrations less than the EPA guideline of 4 pCi/L while 57% of homes tested featuring any radon-resistant construction technique were below 4 pCi/L. The limited data from Watauga county also suggest an increased effectiveness of vented sub-slab systems as a radon-resistant construction technique.