Standards for natural radioactive substances in building materials. K voprosu o normirovanii soderzhaniya estestvennykh radioaktivnykh veshchestu v stroitel'nykh materialakh.

Discusses mechanisms for radon liberation in dwellings. Mentions survey which found radon concentrations exceeding the maximum permissable concentration of 3 x 10^-12 curies in 13 of the 65 dwellings. Gives expressions for number of radon atoms in indoor air at time t and activity due to radon per unit volume. Discusses liberation of radon from walls and from soil and concludes that if the ventilation is poor or if there is a high emanation of radon, the indoor radon concentration may approach the maximum permissable level. This can happen even in houses constructed of materials with a low content of radioactive substances if there is a poor barrier against radon from the soil.