methods were tested in the past: ventilation of indoor air with heat recovery,
radon-proof membranes, protective coating of the floors, etc.
the sub-slab ventilation is considered the most effective system.
of designing and application of various ventilation systems are published in
CSN 730601 Protection of houses against radon from the soil.
- one, or
several perforated tubes drilled beneath existing floors (from the cellar, from
an external chase, or from an internal chase);
- one, or
several radon sumps installed into the sub-floor region of the building;
network of flexible perforated pipes inserted into the drainage layer of coarse
gravel placed beneath the floors (reconstruction of floors necessary);
combination of the above stated measures.
Example: old house with extremely high indoor radon
parameters of the ground
cA75 = 71 kBq.m-3
k75 = 1.6 10-11 m2
RP (radon potential) = 88
high radon index
average indoor radon values: about 35000 Bq.m-3 in habitable rooms; 77000 Bq.m-3 in the cellar
indoor radon concentration in the cellar was the same as the
soil-gas radon concentration in the surroundings of the building
very fast changes of indoor radon concentration were observed
Remedial measures were realized in 2005:
sub-slab ventilation and reconstruction of floors in almost all
sub-slab ventilation system consists of two independent sections
8.45 - 11.8. 9.30
start of the 1st section
9.30 - 18.8. 10.15
sections in operation (maximum power)
10.15 - 22.8. 12.00