Revisiting the concept for evaluation of radon protective properties of building insulation materials

The known evaluation criteria of radon protective properties of building insulation materials are revised. Their main drawbacks are identified both qualitatively and quantitatively. The new concept in the evaluation of radon protective properties of insulation materials is demonstrated by the example of improving one of these criteria. The proposed approach has significantly less uncertainty, mainly due to the use of more representative results of laboratory determination of properties of the “active soil layer” as the main source of indoor radon, instead of highly variable and unreliable results of field measurements of radon concentrations in the soil. The main parameters that characterize the radon protective properties of building insulation materials are the thickness and the radon diffusion coefficient of the insulation material. It is shown that any insulation material with a diffusion coefficient less than 1 × 10−12 m2/s provides a reliable protection of the building against extremely high radon flux from the soil; therefore there is no need for obtaining highly accurate results during the test of such practically impermeable materials. •A new concept in evaluating radon protective properties of insulation materials based on “active soil layer” is suggested.•Field measurements of radon concentrations in the soil are highly variable and unreliable.•The proposed approach has significantly less uncertainty.•Any insulation material with diffusion coefficient