Testing of radon-reducing measures under strictly controlled conditions in a laboratory house

摘要

A laboratory house has been constructed, consisting of two enclosed spaces, simulating a living area (height 2.6 m) with a crawlspace (height 1 m) beneath, both having dimensions of about 3.5 m x 2 m. The two spaces are separated by a concrete floor, 15 cm thick, the air leakage of which can be fully regulated. Phosphogypsum blocks with a total source strength of about 800 Bq radon-222 per hour are placed in the crawlspace. The house is climate controlled and the temperature, humidity, radon concentrations, airflow rates and pressure difference across the floor are registered every ten minutes. The facility can be used to test the effectiveness of various radon-reducing measures quickly, under precisely defined and strictly controlled conditions. In this paper, consideration is given to the use of a polyethylene thin-film membrane and the effects of increased crawlspace ventilation. A so-called airlock floor construction has been found to be the most effective measure, reducing the radon infiltration from the crawlspace by more than 95 per cent.