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CONTRIBUTIONS OF BUILDING MATERIALS TO INDOOR RADON LEVELS IN FLORIDA BUILDINGS
Citation:
Nielson, K., R. Holt, AND V. Rogers. CONTRIBUTIONS OF BUILDING MATERIALS TO INDOOR RADON LEVELS IN FLORIDA BUILDINGS. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/R-96/107 (NTIS 97-104681), 1996.
Impact/Purpose:
information
Description:
The report documents work to characterize potential radon sources in concretes and recommend related changes to Florida's building materials radium standard. (NOTE: The Florida Standard for Radon-resistant Residential Building Construction originally contained a provision to limit the concentration of radium in concrete. The provision was designed to prevent concrete from causing elevated indoor radon concentrations. It was removed from the October 1994 version of the standard, however, because concrete from commercial sources had not been shown to be a major radon contributor in Florida.) A mathematical model is presented to estimate the contributions of building materials to indoor radon levels. The model computes radon flux from concrete surfaces using typical Florida concrete properties, and multiplies the flux by concrete surface areas to estimate their contribution to indoor radon. The model also accounts for building ventilation by outdoor air. A revised building material radium standard was developed to account for the areas and radium concentrations of concretes exposed to building interiors. The standard would limit concrete radon increment from building materials to 2 pCi/L. It would limit concrete radium concentrations to 7-9 pCi/g if only a single slab or walls contain elevated radium. However, it could limit radium to about 3 pCi/g if floor, ceiling, and walls are high.