The Building Regulations (section C2) require that,
“precautions shall be taken to avoid danger to health and safety caused by substances found on or in the ground to be covered by the building”. One such substance is the radioactive gas, radon.
What is Radon?
Radon is a heavy, radioactive gas that is produced as a decay product of Uranium238, a metal that occurs naturally in certain types of soil and rock. Normally levels of radon in the air are not high enough to cause a significant risk to human health. However high levels of radon can build up when houses and other buildings are constructed in areas where the underlying geology contains Uranium238 (typically, but not exclusively granite and limestone areas).
The UK Government’s Health Protection Agency (HPA) advises an “Action Level” of 200 Bq/m3 in domestic properties. In commercial properties, the Ionising Radiations Regulations 1999 require action to protect employees if the average radon gas concentration exceeds 400 Bq/m3. If the level of radon in a building is close to or above these levels, action should be taken to reduce the levels of radon. Radon measurement is normally carried out using small, passive detectors that are left in a building for a period of time before being sent to a laboratory for analysis. These detectors can be purchased from the Health Protection Agency (http://www.ukradon.org/)
Radon Protection and Mitigation
There are a number of measures available for minimising or reducing levels of radon build-up in buildings. These are discussed on the following pages: