Exhalation of Radon 222 from building materials and walls at constant and falling pressures.

Reports study of the exhalation of radon from building materials by following the build-up of activity in closed vessels containing samples of the material. On the basis of a linear diffusion model, the porosity, diffusion length and radon production rate were found for a light-weight concrete by measuring theexhalation at various, constant pressures. The exhalation of radon from wallswas measured in a concrete-walled basement room by studying the growth of activity in exhalation cans sealed to various portions of the walls. Gives main results of exhalation rate for four different materials, slate-based light weight concrete, ordinary concrete, clay-based light weight concrete and bricks, fibreboard and gypsum board.