Building regulations help reduce number of houses with high radon in Clare survey area

Date released: Jul 25 2003

A survey of radon gas in houses in the Ennis area of county Clare built since the introduction of the 1997 amending Building Regulations has found that 12% of houses had annual average radon concentrations in excess of the National Reference Level for houses of 200 Bq/m3.

This percentage represents an improvement on the figure of 28%, which was predicted on the basis of the National Radon Survey. This is one of the key findings of a pilot study published today by the Radiological Protection Institute of Ireland (RPII).

Radon concentrations were measured in 90 dwellings in the Ennis 10-km national Grid Square. All these houses had commenced construction after the introduction of the amending Building Regulations on July 1st 1998 and should, therefore, have had both a radon sump and radon barrier fitted. The results of the study showed that 11 houses had annual average radon concentrations in excess of the Reference Level of 200 Bq/m3. The Institute informed all participants of their results and those with values that exceeded the Reference Level were advised to consider carrying out remedial work. In most cases this would involve sump activation.

The radon concentrations found in this survey for this grid square are significantly lower than those predicted by the National Radon Survey, indicating that the incorporation of radon preventive measures at the time of construction does lead to a reduction in radon levels in homes. However, because a number of houses still had average annual radon levels above 200 Bq/m3, the Institute recommends that all new houses, once occupied, should be tested for radon to determine if sump activation is required.

The 1997 amending Building Regulations, which came into force on July 1st 1998, make Ireland one of the European countries most committed to taking measures to prevent the accumulation of high radon levels in newly constructed buildings. These Regulations require that measures be taken during construction to prevent the entry of radon into all buildings from the underlying soil. These Regulations require that all new dwellings should have a potential means to extract radon from the substructure such as a radon sump. In addition, all new houses in High Radon Areas require the fitting of an approved sealed membrane (radon barrier) of low radon permeability over the footprint of the building.
As part of the study, householders' awareness of the radon preventive measures incorporated into their house was assessed. The level of awareness was found to be low, with 45% and 35% of respondents respectively not knowing whether a radon sump or a radon barrier had been installed.

In its report, the Institute has recommended that the sump outlet be clearly identified to aid its location should sump activation be required. The Department of the Environment and Local Government is in the process of reviewing and amending its Technical Guidance Document C to take account of the Institute’s advice. This documentation is due to be published shortly.
Copy of the Institute’s report is available on our website:


Notes to editors

  • Radon gas is a naturally occurring radioactive gas.
  • Radon is colourless, odourless and tasteless and can only be measured using specialised equipment.
  • Radon is formed in the ground by the radioactive decay of uranium which is present in small quantities in rocks and soils.
  • Being a gas, radon has the ability to move through the soil and enter buildings through any small cracks, holes or imperfections that may exist in the floor area.
  • Once in a building radon quickly decays to produce radioactive particles which are suspended in the air.
  • When inhaled these particles can be deposited in the airways and attach themselves to lung tissue. This gives rise to a radiation dose which may eventually cause lung cancer.
  • From 1992 to 1999, the RPII carried out a National Survey of Radon in Dwellings. This survey classified areas in which greater than 10% of dwellings are predicted to have annual average radon concentrations
  • greater 200 Bq/m3 as High Radon Areas. Approximately 33% of the country is classified as a High Radon Area.
  • Download full report: Radon levels in Domestic Dwellings Built Since the introduction of the 1997 Building Regulations