Testing positive pressurization technique against radon indoor accumulation

Abstract

Radon is one of the common contaminants inside buildings, with maximum presence in high potential areas classified as radon prone areas. This radioactive gas, which comes from the spontaneous disintegration of radium present in the earth's crust, can penetrate buildings and accumulate inside them. The spaces closest to the ground (basement and first floors) are the most affected. Its inhalation in high doses is associated with an increased risk of lung cancer. Several techniques are commonly used to mitigate its presence. One of them consists of blowing air from the outside to internal spaces, generating a double effect of interior pressurization and dilution of the gas. The effectiveness of this technique, and the implications on energy efficiency, depend on the constructive characteristics of the building, the volume, and the initial state of concentration. This paper presents the preliminary results of a study to characterize the effectiveness of the technique for three different types of buildings located in an area of high radon potential. The system applied consist in a commercial fan that blow air from outside to the indoor living spaces. Two types of fans have been used function of flow rate according to indoor volume of the three types of buildings. Several test have been carried out: envelope airtightness, indoor/outdoor and indoor/underground differential pressure measurements, flow rates, and continuous monitoring of radon levels for set ups analysis. The data show radon reductions between 47 and 96% for the different test sets. By adjusting the design variables, radon levels have been reduced to below 300 Bq/m3 (European Directive) for all three buildings.