Design Criteria for Achieving Low Radon Concentration Indoors

Design criteria for achieving low radon concentration indoors are presented in this paper. The paper suggests three design criteria. These criteria have to be considered at the early stage of the building design phase to meet the latest recommendations from the World Health Organization in most countries. The three design criteria are; first, establishing a radon barrier facing the ground; second, lowering the air pressure in the lower zone of the slab on ground facing downwards; third, diluting the indoor air with outdoor air. Three criteria when used can prevent radon infiltration and lower the radon concentration in the indoor air. In addition, a cheap and reliable method for measuring the radon concentration in the air indoors is described. The provision on radon in the Danish Building Regulations complies with the latest recommendations from the World Health Organization. Radon can cause lung cancer and it is not known whether there is a lower limit for when it is not harmful to human beings. Therefore, it is important to reduce the radon concentration as much as possible indoors in buildings. Airtightness is an important factor when dealing with buildings. For the building envelope above the ground it is important to avoid infiltration e.g. in compliance with energy requirements and towards the ground it is important to avoid infiltration e.g. of radon, to meet the requirements to ensure and control the indoor environment. Infiltration of air from the ground underneath a building is the main providing source of radon indoors.