Protection against radon
Radon is emitted from radium-containing materials in the ground, and from certain concrete-type building materials, known as Blue Ytong, in older buildings. In order to prevent ground radon from finding its way into buildings, the surface of the ground beneath the building can be covered by a radon-impermeable membrane or barrier. The emission of radon from building materials, e.g. in walls, can sometimes be dealt with by radon-impermeable wallpapers or films.
SP has test equipment for measuring the impermeability of various materials to radon.
The test procedure
The test equipment consists of two chambers, primary and secondary, each with one open side. The material to be tested is placed between them, and a radon source is placed in the primary chamber.
Radon emission from the source increases the radon concentration in the primary chamber and changes the relative concentration in the two chambers, so that radon diffuses through the test material. Only radon gas (Rn) passes through the material, and not the radon daughter products (RnD).
The test results are expressed as radon permeance, determined by measuring the radon concentrations on both sides of the test material when exposed to radon on one side.
If the thickness of the test material is known, then its radon permeability can also be calculated.
Tests take about 4-6 days.