Experience has shown that radon levels may vary significantly from one building to the next and that the radon level in a house cannot be reliably inferred from measurements in other houses in the neighbourhood. Consequently, the The Irish Radiological Protection Institute recommends that all householders have a radon measurement made to determine the radon level in their home. Where high radon levels are found, householders are advised to consider having remedial work carried out to reduce the radon level.

The radon level in your house can be measured simply and inexpensively. It is usually carried out by placing a small testing devices, (see below), in the house for a period of three months or six months. At the end of the test you return the tester to our laboratory where it will be analysed. As the detectors can be sent by post there is no need for a technician to call to your home.

Radon levels in a building can change greatly from day to day due to changes in the weather conditions, ventilation, building usage, etc. A measurement period of at least three months is recommended, as it is generally considered that a measurement taken over a shorter period does not give an accurate representation of the exposure to radon in the home.

Technical Guidance Document C of the 1997 Building Regulations effective since July 1998, stipulates every new house is required to incorporate some degree of radon preventive measures at the time of construction in accordance with the revised Building Regulations. The degree of protection required is dependent upon whether the site is located within a high or low radon area.

Building Regulations -

Construction of new dwellings or long stay residential buildings. There are two levels of protection specified:-

High Radon Areas are areas where it is predicted that more than 10% of the houses have radon concentrations above the Reference Level. In order to determine the radon designation of an area,

• The basic or precautionary measures which apply to new buildings across the country
• The more advanced measures which apply to all new buildings in designated High Radon Areas.

The exact grid co-ordinates of the site should first be determined by consulting the appropriate Ordnance Survey map. The Ordnance Survey's Road Atlas of Ireland or Holiday Map (1:250,000) series are normally suitable for this purpose.

For all parts of the country, the Building Regulations require that new buildings include a potential means of reducing radon levels, should high levels be found in the completed building. In the case of dwellings of normal construction, this is most commonly achieved by means of a radon sump, as described in the Department of the Environment's publication "Radon in Buildings". The Radiological Protection Institute of Ireland recommends that, once occupied, all new buildings should be tested for radon. If the radon level is found to be above the Reference Level then the radon sump, or other means of reducing the radon levels, should be activated.

In High Radon Areas, the Building Regulations require that, in addition to providing a potential means of reducing radon levels, measures should be taken to protect the building from radon in the ground. For a dwelling of normal construction, this means that a fully sealed low-permeability membrane should be provided in addition to a radon sump.

Copies of Technical Guidance Document (C), and the Department of the Environment's publication "Radon in Buildings" may be purchased from the Government Publications Sale Office (Molesworth Street, Dublin 2 - Tel. (01) 661 3111).