NEW METHODS OF ENERGY-EFFICIENT RADON MITIGATION

Two new radon mitigation techniques are introduced and their evaluatio n in a field study complemented by numerical model predictions is desc ribed. Based on numerical predictions, installation of a sub gravel me mbrane at the study site resulted in a factor of 2 reduction in indoor radon concentrations, Experimental data indicated that installation o f ''short-circuit'' pipes extending between the subslab gravel and out doors caused an additional factor of 2 decrease in the radon concentra tion. Consequently, the combination of these two passive radon mitigat ion features, called the membrane and short-circuit (MASC) technique, was associated with a factor of 4 reduction in indoor radon concentrat ion. The energy-efficient active radon mitigation method, called effic ient active subslab pressurization (EASP), required only 20% of the fa n energy of conventional active subslab depressurization and reduced t he indoor radon concentration by approximately a factor of 15, includi ng the numerically-predicted impact of the sub-gravel membrane.