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U.S. Department of Energy
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Monitoring and evaluation of radon mitigation systems over a two-year period

Conference ·
OSTI ID:6714922

Fourteen single-family detached houses in the Spokane, Washington, and Coeur D'Alene, Idaho, area were tracked for two years following mitigation for elevated indoor concentrations of radon. Each house was monitored quarterly using mailed alpha-track radon detectors deployed in each zone of the structure. During the second heating season following mitigation, radon concentrations were monitored continuously for several weeks in seven of the houses, each house and mitigation system was inspected and selected measurements were performed in order to access mitigation system performance. Occupants were also interviewed regarding their maintenance, operation, and subjective evaluation of the radon mitigation system(s). The quarterly alpha-track measurements showed an increase in radon levels in a majority of the homes during many of the follow-up measurement periods compared to concentrations measured immediately after mitigation. The greatest increases in radon concentrations occurred in 3 of the 4 houses equipped with basement pressurization systems where radon levels approached the pre-mitigation levels during at least one of the follow-up measurement periods. In some of the houses mitigated with subsurface ventilation, radon concentrations generally increased over the course of the follow-up periods. Factors causing decreased mitigation system performance included: (1) build up of debris on the soil at the outlet of subsurface pressurization pipes; (2) noisy and vibrating fans were turned off; (3) air-to-air heat exchanger, basement pressurization, and subsurface ventilation fans were turned off and fan speeds reduced; and (4) crawl space vents were closed or sealed. 7 refs., 2 figs., 2 tabs.

Research Organization:
Lawrence Berkeley Lab., CA (USA)
DOE Contract Number:
AC03-76SF00098
OSTI ID:
6714922
Report Number(s):
LBL-25909; CONF-8810134-3; ON: DE89002921
Country of Publication:
United States
Language:
English