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DEMONSTRATION OF RADON RESISTANT CONSTRUCTION TECHNIQUES - PHASE II. FINAL REPORT
Citation:
Tyson, J. AND C. Withers. DEMONSTRATION OF RADON RESISTANT CONSTRUCTION TECHNIQUES - PHASE II. FINAL REPORT. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/R-95/159 (NTIS PB96-121512), 1995.
Impact/Purpose:
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Description:
The report gives results of a demonstration of radon resistant construction techniques. Sub-slab mitigation systems were installed (in accordance with draft standards) in 15 new Florida houses in 1992, and these houses have undergone extensive testing to validate techniques used to prevent radon intrusion. Soil radon levels ranged from just under 500 to over 8000 pCi/L. All systems have been determined to extend negative pressure to practically all areas under the slab. Slabs tended to crack less than expected. Intact vapor barriers under new houses prevent radon intrusion through slab cracks in most instances. Slab pipe penetrations not sealed in accordance with standards contribute relatively higher amounts of radon into the house. Eleven mitigation systems were installed using ventilation matting, and four systems used wellpoint suction pipe. Both systems perform well as long as they are installed carefully. The highest indoor radon level with the mitigation system capped off was 5.6 pCi/L for a 48 hour period. Ten houses were under 2.9 pCi/L, the action level for a 48-hour measurement by continuous radon monitor, and did not require activation of their mitigation systems. Five houses required activation of their mitigation systems after the uncapped system test. All houses are currently under the action level.