An investigation of a passive opened top-end pipe as an alternative solution for passive soil depressurisation systems for indoor radon mitigation.

This study carried out a series of large-scale experimental tests and numerical simulations to investigate the performance of a passive opened top-end pipe as an alternative solution for passive soil depressurisation systems for indoor radon mitigation. Measurements were conducted in terms of wind velocity, extracted air velocity and negative pressure at the sump-end inside the pipe. Investigations were performed with controlled and natural wind conditions. Test results confirmed that the passive opened top-end pipe can be used as an alternative solution for indoor radon concentration mitigation at low additional construction cost. However, the extracted air velocity and negative pressure were found to fluctuate when tested under natural wind conditions. This fluctuation would reduce the effectiveness of the performance of the passive pipe. To reduce this fluctuation, a novel static ventilator has been developed and can be added on the top-end of the pipe.