Radon is a naturally occurring radioactive gas. It has no taste, colour or smell. It is formed in the ground by the radioactive decay of uranium which is present in all rocks and soils. You cannot see it, smell it or taste it. It can only be measured with special detectors.
The Building Regulations require the installation of radon preventive measures to minimise the level of radon in new homes.
The World Health Organisation has categorised radon as a carcinogen, in the same group as asbestos and tobacco smoke. In Ireland, up to 250 cases of lung cancer each year are linked to exposure to radon. Smoking and radon work together with the result that smokers are at much greater risk of developing radon related lung cancer than non-smokers. There is no scientific evidence linking radon with any other types of respiratory illnesses or other cancers.
Radon can enter a building from the ground through small cracks in floors and through gaps around pipes or cables. Buildings in some parts of the country are more likely to have a radon problem. These parts of the country are called High Radon Areas. You can check our interactive map to see whether a building is in a High Radon Area. Outside radon is diluted to very low levels.
The acceptable level, or Reference Level, for homes and schools in Ireland is 200 becquerel per cubic metre (Bq/m3). For workplaces the Reference Level is 400 Bq/m3.
Over a long period of time, exposure to radon can increase your risk of developing lung cancer. Radon produces tiny radioactive particles. When they are inhaled these particles can be deposited in the airways and result in a radiation dose to your lungs. There is a synergistic effect between radon and lung cancer. This means that smokers are at much greater risk of developing radon related lung cancer than non-smokers.
The risk of developing radon related lung cancer
Your risk of contracting lung cancer from exposure to radon depends on:
- how much radon you have been exposed to
- how long you have been exposed to this level of radon
- whether or not you are a smoker (smokers are at 25 times more risk from radon than non-smokers)
To find out more read our radon and your health leaflet
Buildings in some parts of the country are more likely to have a radon problem. These parts of the country are called High Radon Areas. You can check our interactive map to see whether a building is in a High Radon Area. The only way to know how much radon is in a building is to take the radon test.
For buildings built since 1st July in High Radon Areas the installation of a radon barrier is required.
There is no published national standard setting out the required specifications for radon barriers. However, the National Standards Authority of Ireland has issued technical certification for a number of radon barriers. The NSAI Agrément Certificates establish proof that the certified products are ‘proper materials’ suitable for their intended use under Irish site conditions, and in accordance with the Building Regulations.
The Building Regulations also require that all buildings built since 1st July 1998 are fitted with a standby radon sump. This is simple pipe work that extends from under the foundations into the outdoor air. If high radon levels are measured, the standby sump can be activated by adding a fan. It should be noted that a standby sump that has not been activated by adding a fan does not reduce radon levels in a building.
Training and CPD
Correct installation of passive preventive measures in new buildings is the most cost effective way of protecting the population against radon. Research has shown that, on average, radon levels in houses built after 1998 in high radon areas are lower than in those built before 1998 by approximately 25%. However, the installation of a radon barrier cannot guarantee that radon in an individual building will be below the Reference Level and the quality of the installation is critical to the success of the barrier.
A short training course in radon preventive measures has been developed and will be rolled out by the Construction Industry Federation during 2017. Once available, more information will be available on this website.
A two day training course on radon remediation measures has been developed and was offered to remediation specialists and staff of State bodies during 2016. This course is a prerequisite to being listed as a registered radon remediation company will be run again where there is demand.
Testing for Radon
The EPA recommends that all buildings are tested for radon, including those that have radon preventive measures installed.
Testing a home for radon
Please watch our animated video to see how easy it is to test a home for radon.
A radon test is carried out by placing two small detectors, about the size of a match box, in a home for three months. One detector is placed in a bedroom the other in a living room - the places most occupied by the family. After three months, when the detectors are posted back to the laboratory, they are analysed to see how much radon they have been exposed to in the home.
The results of the radon test are then posted to the homeowner. If the results are high, advice on what to do next will also be included.
Radon levels can vary a lot between homes so all homes should be individually tested.
How do I test the levels of radon in a workplace?
A workplace is tested by placing one small detector, about the size of a match box, in each occupied room on the ground floor or in the basement. Only those workplaces with an occupancy of more than 100 hours per year need be measured.
After three months, when the detectors are posted back to the laboratory, they are analysed to see how much radon they have been exposed to. It is a legal requirement that radon testing in the workplace must be carried out for at least three months. Once the results are known, a report is issued setting out radon level in each room tested. More details about testing your workplace for radon are available in our booklet.
For underground workplaces such as caves and mines, the EPA has produced specific guidance.
How do I test the levels of radon in a school?
A radon test is carried out by placing a small detector, about the size of a match box, in every occupied ground floor classroom and office for three months (it is not necessary to test corridors, bathrooms or storage areas). After three months, when the detectors are posted back to the laboratory, they are analysed to see how much radon they have been exposed to. A copy of the results will then be sent to both your school and the Department of Education and Skills. Where radon levels are above 200 Bq/m3, remedial work should be carried out.
Buying a radon test
The EPA provides a list of registered radon testing services.
Reducing High Levels
If the results from your radon test show that the radon levels in your home are high there are a number of simple ways that you can reduce these levels. The EPA provides a list of registered remediation contractors that will carry out this work.
Please watch our video to see how easy it is to reduce radon levels in your home.
The best way to reduce radon depends on the levels in your home and the building type. Here is a guide to the methods most commonly used:
Improving indoor ventilation
One of the simplest ways to dilute moderate levels of radon is to increase the indoor ventillation by installing wall vents or window trickle vents. This can reduce radon levels in a building by up to 50%. It is important that increased ventilation is installed at ground level only as additional ventilation on upper floors may increase the flow of radon from the ground into your home. This work usually costs in the region of a few hundred euro.
Improving under-floor ventilation (for homes with suspended floors)
If a building has a suspended floor you can also reduce the amount of radon entering the building by increasing the sub-floor ventilation. Clearing or replacing existing sub-floor vents or installing additional vents or airbricks will increase the flow of air below the floor and so reduce the amount of radon entering your home. This work usually costs in the region of a few hundred euro.
Installing a passive sump
For radon levels up to 400 Bq/m3, a passive sump can reduce radon levels by up to 50%. A passive sump is a sump system that works without the action of a fan. Instead, wind action over the top of the sump-pipe (which often is fitted with a rotating vane or ventilator) draws radon up through the sump system.
Installing an active radon sump
The most effective and most commonly used way of reducing the flow of radon into a building is by installing an active radon sump. A radon sump is a cavity about the size of a bucket immediately under the floor slab that is linked by pipe work to the outside. The radon rich air coming from the ground is drawn out from under the floor slab by a small electric fan in the pipeline and vented to outside before it is drawn into the building. This can reduce radon levels in your home by about 90% and sometimes up to 99%. An active radon sump can usually be installed in one day and all the work is carried out from outside the building. The work typically costs about €925, but this can range from €400 to €1500, depending on the complexity of the work. The annual running cost of the fan depends on the power of the fan used. The running costs range from about €30 using a 14 watt fan to about €150 for a 70 watt fan. Typically an active sump can reduce radon levels by about 90% but this may range from 60% to 99%.
Normally remediation is successful at the first attempt. However, sometimes more work is needed to reduce the radon levels to below 200 Bq/m3. There is no absolute certainty that radon will be reduced to below 200 Bq/m3 even following a number of remediation attempts. While this rarely happens, it is important to note that any significant reduction in radon levels will reduce the risk of lung cancer even if the levels are not reduced below the Reference Level.
For active sump systems it is important to ensure that fans are maintained. It is also important to ensure that passive ventilation systems remain clear from debris.
It is important to have the building re-tested after the work has been completed, to ensure that it has reduced the radon levels to below the Reference Level. The EPA provides a free post-remediation service to homeowners.
Further information about radon is available here:
Registered Radon Remediation Services
Under the National Radon Control Strategy a registration scheme for radon remediation services has been developed. Registered remediation contractors have met a number of requirements including attendance at a training course on remediation, followed by a successful assessment, adherence to a cope of practice, tax compliance, appropriate insurance, etc. Further details of this registration scheme are available in the Radon Remediation Registration Form.
The EPA provides this list of registered remediation contractors to those that wish to reduce radon levels in their buildings. The EPA recommends discussing the following with the contractor:
- Fan warranty and maintenance (for active sumps)
- Costs of running fans (for active sumps)
- Fan noise – if possible fans should be located away from bedrooms as they may be heard especially at night (for active sumps)
- Post remedial measurements
- What steps may be taken and the potential cost (if any) if further work is needed following re-testing
Following the remediation work the EPA advises that:
- It is very important to re-test your building after the work is completed to ensure that radon levels have been reduced to below the Reference Level. The EPA provides a free post-remediation measurement service to all homeowners.
- Although remediation is usually successful at the first attempt, sometimes more work is needed to reduce the radon levels to below the Reference Level.
- There is no absolute certainty that radon will be reduced to below the Reference Level even following a number of remediation attempts. While this rarely happens, it is important to note that any significant reduction in radon levels will reduce the risk of developing radon related lung cancer.
Registered Radon Testing Services
Also under the National Radon Control Strategy, a registration scheme for radon measurement services has been developped. Registered radon measurement services have provided evidence of successful proficiency testing, tax compliance and appropriate insurance. Further details of this registration scheme are available in the Registration Form and Guidelines. Listed services have also agreed to comply with the Environmental Protection Agency's Radon in Air Measurement Protocol.
To determine whether the radon levels in a workplace exceed the Reference Level the Regulations require that the test should be carried out over a minimum period of three months. For homes a minimum three month measurement is also recommended by the EPA. For these measurements, the use of passive detectors is generally the most cost effective and the most straightforward approach.