Ensuring the safety and integrity of structures in contact with the ground includes not only watertightness but also protection against radon – a hidden yet significant health hazard. Radon protection systems are essential in buildings to prevent the accumulation of radon, a harmful, invisible, and odorless radioactive gas naturally emitted from the ground.
We have put together a comprehensive guide about radon, explaining what it is, the risks of radon exposure, various radon regulations worldwide, as well as how to prevent and reduce radon in buildings and homes.
What is Radon?
Radon, a naturally occurring radioactive gas, is an often overlooked yet critical aspect of building safety. This invisible, odorless, and tasteless gas is a product of the natural decay of uranium-238, an element commonly found in soils and rocks. As a noble gas, radon is chemically almost inert, but its radioactivity poses significant health risks. In fact, it is the second leading cause of lung cancer in the general population, next to smoking.
The World Health Organization (WHO) reports that radon is responsible for 3% to 14% of lung cancer cases, depending on the geographical area and the average radon levels in buildings. Alarmingly, there is no safe threshold for radon exposure; even low concentrations contribute to a heightened risk of lung cancer.
Where is Radon Found?
Radon’s presence is not limited to specific geographical locations; it can be found globally, with concentrations varying widely from one region to another. Factors such as the local geology, soil composition, building materials, and construction methods all influence radon levels in indoor environments.
One of the unique characteristics of radon is its ability to move freely through soil, eventually permeating into buildings. This infiltration typically occurs through cracks in foundations, gaps around pipes, or any other openings in structures in contact with the ground.
Once inside, radon can accumulate, especially in poorly ventilated areas, creating an invisible health hazard. Residential homes, schools, and workplaces are common settings where radon accumulation can occur, often unbeknownst to the occupants.
What You Should Know About Radon
This means it is produced when uranium decays. Uranium is found everywhere in the ground. It is invisible, tasteless and odorless and has a half-life of 3.8 days.
The mother isotopes of radon occur everywhere in the soil. They get into buildings through joints, cracks, and leaky pipes in all components that come into contact with the ground and then spread throughout the entire house.
The radioactive decay damages the bronchi, which can lead to lung cancer. Follow-up products are lead, bismuth, polonium.
The WHO has set a national reference level of 100 Bq/m³ for indoor radon, with a maximum acceptable level of 300 Bq/m³. This is comparable to the radiation exposure from one heart and lung x-ray per day.
Global Standards for Radon Protection
Around the world, the approach to managing radon risk in buildings varies, reflecting differing geographical radon concentrations and health policy priorities. While the specifics differ, a common goal unites these efforts: the reduction of radon levels to protect public health. Understanding these diverse standards is crucial for architects, builders, homeowners and building owners alike, ensuring compliance and safety across various regions.
Canada
The Canadian guideline for radon is 200 becquerels per cubic meter (Bq/m³).
Corrective actions need to be completed:
- in less than 1 year, if the radon level is greater than 600 Bq/m³
- in less than 2 years, if the radon level is between 200 Bq/m³ and 600 Bq/m³
USA: Environmental Protection Agency (EPA)
The EPA recommends taking action to reduce radon levels in buildings when they reach or exceed 4.0 pCi/L, equivalent to approximately 148 Bq/m³ (1 pCi/L = 37 Bq/m³).
Norway
- The indoor radon concentration (in the finished building) shall not be over 200 Bq/m3 of air.
- Buildings planned for long-term occupation shall have a radon barrier against the ground.
- Buildings planned for long-term occupation shall have suitable mitigation structures in the foundations which can be activated (.e.g. an electric fan) when the indoor concentration exceeds 100 Bq/m3.
Finland
- The reference level for the radon concentration in indoor air in dwellings and other living areas is 300 Bq/m3 of air.
- In designing and constructing new buildings, the reference level for the radon concentration in indoor air is 200 Bq/m3.
- The Finnish Radiation Decree defines reference values for radon levels in the workplace. Employees who work regular hours (more than 600 hours per year) must not be exposed to radon levels in excess of 300 Bq/m3 on average per year. The same reference value also applies to schools, nurseries and other public buildings.
Germany: Verordnung zum Schutz vor der schädlichen Wirkung ionisierender Strahlung
By the end of 2020, German states (Länder) were required to identify areas where high radon levels in buildings are expected, in accordance with the Radiation Protection Act.
- Regulations for Existing Private Homes: Owners and residents are encouraged, but not mandated, to take voluntary measures to reduce radon levels.
- New Private Buildings: Owners must implement structural measures to significantly prevent radon infiltration.
- Workplaces: Mandatory action is required if radon concentrations exceed 300 Bq/m³, focusing on reducing indoor radon levels.
- Standard for Radon Protection: The Radiation Protection Act sets a reference value of 300 Bq/m³ for evaluating the effectiveness of radon mitigation measures.
Spain: Technical Building Code (CTE) Part H6
Spain sets a reference level for the annual average indoor radon concentration at 300 Bq/m³ to limit user exposure.
France
France decreed the following limits on February 20, 2019:
- Below 300 Bq/m³: No specific measures required; regular ventilation is sufficient.
- Between 300 and 1000 Bq/m³:
- Regular Ventilation: Continuation of standard ventilation practices.
- Sealing Against Radon Entry: Focus on sealing areas like cellar doors, pipe entries, and floor cracks.
- Improving Basement Ventilation: Enhance or restore natural ventilation in basements, including unblocking crawl spaces or cellar vents. - Above 1000 Bq/m³:
- Building Airtightness: Ensure airtightness at critical points (pipes, doors, hatches) between basement and living spaces, and treat dirt floors.
- Increased Air Renewal: Focus on enhancing air turnover in occupied rooms.
- Basement Treatment: Aim to reduce radon entry by ventilating the basement or creating a slight air pressure depression in relation to the occupied volume, using mechanical extraction where possible.
Austria: Österreichisches Institut für Bautechnik - Radon Protection Ordinance (RnV)
In general, buildings with habitable rooms in radon precautionary or protection areas must be designed to prevent health-hazardous radon ingress from the subsurface. Compliance with a reference value of 300 Bq/m³ for radon activity concentration as an annual average in occupied rooms is considered satisfactory.
Classification of Areas:
- Areas Without Classification: No structural measures for radon protection are required.
- Radon Precautionary Areas: Convection-tight design of components in contact with the ground is necessary, as per ÖNORM S 5280-2, edition 15.07.2021.
- Radon Protection Areas: Alongside convection-tight design, installation of radon drainage is recommended, following the same standard.
Radon Protection Measures
There are three main ways to ensure effective radon protection:
1. Ground-Level
Defense
Radon is prevented from entering the building from the ground, where radon originates
Ensure that radon is blocked from infiltrating your building from the ground. This includes sealing openings and other penetrations in the building envelope with sealants or tapes that prevent radon ingress and installing a robust radon barrier.
Sika provides a comprehensive selection of waterproofing membranes and sealants. These not only offer excellent waterproofing capabilities but also ensure a high level of protection against radon gas infiltration, as verified by independent testing.
2. Ventilation
for Radon Reduction
Radon is transported out of the bulding, reducing its concentration in the premises
Implement natural or mechanical ventilation systems that actively transport radon out of the building, effectively reducing its concentration within the protected premises.
3. Proactive Removal
Radon is actively removed if it enters the building or before it enters the premises
Take proactive measures to eliminate radon before it even enters the building. Early detection and removal techniques can significantly reduce the presence of radon gas.
Please note: regulations in different countries may establish varying levels of intervention based on detected radon concentrations, reinforcing the importance of tailored radon protection strategies.
Radon Barrier Effectiveness Criteria
When it comes to protecting against radon, the effectiveness of radon barriers plays a key role.
Different countries have established specific criteria to determine what constitutes an effective radon barrier; for example:
Germany
Material Thickness and Diffusion Penetration: a material is considered radon-tight if its applied thickness exceeds thrice the diffusion penetration length obtained through testing.
UK
Building Research Establishment (BRE) Report BR 211:2023, a typical radon transmission rate for a radon-resistant membrane is 12 x 10^-12m²/s.
Spain
Technical Building Code (CTE) Part H6, Simplified Criteria: A radon diffusion coefficient of less than 10^-11 m²/s and minimum thickness of at least 2 mm. Spain also specifies performance characteristics of the protective barrier, including ensuring the barrier is continuous, crack-free, and durable, as well as sealing interrupting elements and doors.
Find Radon Protection Products
Are you uncertain about the radon protection requirements for your project, or which radon barrier is the perfect fit? Perhaps you’re seeking insights into the local standards governing your project’s location. Maybe you’re eager to explore Sika’s extensive range of radon protection solutions, including bonded membranes, liquid applied membranes, and joint sealing products, as well as the latest advancements in radon mitigation.
Visit our Radon Protection Solutions page for more information and to explore our product portfolio.
Speak to Our Radon Expert
When it comes to radon protection, expert guidance can make all the difference. Our dedicated radon expert, Albert Berenguel, is here to assist you in creating a safer and healthier indoor environment. Whether you have questions, need personalized recommendations, or require assistance with your radon protection project, don’t hesitate to reach out for expert insights and support.
Albert Berenguel
Market Development Manager
Waterproofing
Sika Services AG