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HOW TO INCREASE THE EFFECTIVENESS OF EXISTING MEASURES

Ineffective existing measures can be transformed into highly effective measures by simple, cheap and wellproven procedures. In most cases, the required efficiency can be achieved by changing the passive ventilation of the subsoil or of the floor air gaps into active ventilation powered by a suitable fan. This improvement can be installed without any intervention into existing floors, and without introducing obstructions into the living space of the house. The fan is preferably installed on an existing vertical exhaust pipe, either at the top of the pipe above the roof (Fig. 1), or inside the attic. If this arrangement cannot be applied, the existing subsoil ventilation system (Fig. 2) or floor air gap ventilation system (Fig. 3, 4) can be connected to a fan installed outside the house. Existing vent holes in the perimeter foundations that deliver the outdoor air into the subsoil or into air gaps need to be closed to prevent the floors being cooled in winter due to suction of the cool outdoor air under the floors. It is considerably cheaper to install and operate fans than to decrease the indoor radon concentration by enhanced ventilation of the living space. The power consumption of a fan is comparable with the power consumption of an ordinary 40 W bulb.


Fig. 1 - Changing the passive ventilation of the subsoil into active ventilation by installing a fan or a rotating cowl at the top of the vertical exhaust pipe.


Fig. 2 - Changing the passive ventilation of the subsoil into active ventilation by connecting the existing vent holes on one side of the house to the fan installed outside the house.


Fig. 3 - Connecting of existing holes ventilating the floor air gap to the fan installed outside the house. The interconnecting pipe runs under the ground surface.


Fig. 4 - Various possibilities of a fan positioning.


Fig. 5 - The effect of the floor air gap ventilation on the indoor radon concentration.  Operating periods of the fan are adjusted according to continuous measurements of indoor radon concentration.