Understanding and mitigating the risks of radon gas

Radon has become a pressing concern for homeowners and occupants across the globe. The odourless and tasteless radioactive gas, formed through the natural decay of uranium in soil and bedrock, has been identified as a Category 1 carcinogen by the International Agency of Research on Cancer (IARC), putting it in the same league as asbestos and benzene in terms of cancer-causing potential.

According to the Health Canada website, radon gas breaks down to form radioactive elements that can be inhaled into the lungs. “In the lungs, radon continues to breakdown, creating radioactive particles that release small bursts of energy. This energy is absorbed by nearby lung tissue, damaging the lung cells. When cells are damaged, they have the potential to result in cancer when they reproduce.”

“There’s no scent or taste to radon, but it does impact us when we breathe, and the only known impact is lung cancer,” says Pam Warkentin, executive director of the Canadian Association of Radon Scientists and Technologists (CARST), which works to raise radon awareness across the country, and aims to be a trusted radon resource for organizations, including HVAC contractors, plumbers and other professionals in the homebuilding and construction sectors. Established in 2011, CARST works with federal and municipal stakeholders on matters of policy and advocacy, developing standards, consulting on building codes and providing learning opportunities and training through their national certification program.

The long-term health effects of radon exposure have been researched for decades, and Warkentin says Health Canada determined in 2004 that even low concentrations of radon can increase the risk to humans, especially with longer durations of exposure. Thus, understanding the significance of radon gas and raising awareness about its potential risks and mitigation strategies is paramount. For homebuilders, contractors and professionals in the HVAC and plumbing industries, conversations about radon safety demonstrate a commitment to the safety and well-being of their clients.

“We encourage positive conversations about being proactive and preventative, bringing up information about radon early so that homeowners can prepare for it,” Warkentin says.

Understanding radon gas
Radon gas is a naturally occurring byproduct of soil and rock decay, which makes its presence ubiquitous in all types of soil and bedrock. “Radon comes from uranium,” Warkentin explains. “As uranium and radium go through part of the decay chain, they stay in the ground. Once it becomes gas, it moves easily out from the ground.”

Though radon exists in the air day to day, Warkentin says the real risk occurs when radon enters a building, coming in at an elevated concentration and introducing exposure in greater duration.

Almost all houses in Canada have some amount of radon gas. However, radon concentrations vary from province to province and from house to house as many factors affect the final indoor levels, says Fadi Basmaji.

Engineers, plumbers and HVAC contractors can play a role in mitigating. Photo courtesy of IPEX.

Basmaji is a Product Specialist at IPEX Inc., which designs and manufactures integrated thermoplastic piping products, including the RadonX Soil Gas Venting system. He says like other soil gases, radon can enter homes or buildings by a difference in air pressure. “Drains, cracks in the foundation wall and slab, gaps around pipes, and other openings provide points of entry for the soil gases,” he adds. “A combination of radon-enriched soil, entryways into the home or building and reduced passive ventilation without radon-reduction strategies is a recipe for elevated radon levels within the occupied spaces.”

Implications for contractors
Radon concentrations in indoor air can be reduced by impeding the flow of soil gases to areas in contact with the home or building. This can be achieved by eliminating all openings to the soil through the foundation, completely sealing all contact points of the building with the soil, and reducing the pressure difference between the soil beneath the home or building to prevent soil gases from entering. However, Basmaji cautions, this method alone is both impractical and ineffective. “Radon can enter through even the most miniscule cracks,” he notes, adding that while most cracks will be sealed during construction of the home or building, settlement will occur over time, causing new cracks and points of entry to appear. Because of these factors, radon prevention and mitigation strategies are crucial when it comes to construction planning and execution.

For existing buildings, Warkentin says there are easy measures to mitigate radon. She refers to the Canadian General Standards Board (CGSB), which has released radon mitigation options for existing and new construction in low-rise residential buildings. Furthermore, the 2020 National Building Code provides recommendations for how to collect and vent radon in large buildings.

“In new construction, there are three installation methods of soil gas vent piping: Level 1 (radon rough-in), Level 2 (full passive stack) and Level 3 (active stack),” Basmaji says. A Level 1 rough-in does not fully reduce radon levels, but allows for the future addition of a full passive or active system if the home tests high for radon after occupancy.

“The 2020 National Building Code (section 9.13.4.2) mandates a Level 1: rough-in for an active soil depressurization system as the minimum preventative measure for radon control in all new construction homes built in regions that adhere to this building code,” Basmaji adds.

He explains that installing a Level 2 full passive vent stack, which consists of a perforated pipe below the foundation floor that collects radon gas, and a full vent stack that runs upwards throughout the inside of the building releasing the gas outside above the roof, can reduce indoor radon levels. But, if radon levels are still detected in excess of Health Canada’s recommended concentration if 200 Becquerel per square metre (Bq/m³), the installation of a radon fan to the vent stack, which converts the depressurization system into an active one, can further reduce radon levels.

Basmaji also recommends the installation of the RadonX rain cap from IPEX to protect the vent stack from unwanted debris and rain while maintaining airflow. The patent-pending design has three vent screens for improved air movement and extended caps to protect the stack from rainfall, preventing condensation and ice build-up from blocking the openings. The rain cap is part of IPEX’s RadonX soil gas venting system, which also consists of a PVC gas collection (perforated) and vent (non-perforated) pipes, fittings, solvent cement and termination accessories.

Becoming part of the solution
For contractors, Basmaji and Warkentin advise becoming familiar with the unique standards required for different types of buildings and municipalities.

“For Part 3 Buildings, air barrier materials are required as a minimum to prevent uncontrolled air leakage which could allow radon gas to collect inside a building. Additionally, EPA 625/R-92/016 has been referenced in Section 6.2.1.1 Good Engineering Practice of the National Building Code 2020, providing recommendations for how to collect and vent radon in large buildings,” he says.

The building’s location may also impact which radon provisions apply. Warkentin says the building code in Ontario recommends additional levels of protection for higher-risk areas within the province.

“For municipalities that have done radon surveys and found they’ve had a percentage of homes above guidelines, we are seeing communities adopting [a Level 2 or Level 3 protection requirement in new construction].”

And, Basmaji continues, some municipalities have authority over which regulations apply to their area, potentially adding new radon provisions to building codes. “For example, the city of Guelph [Ontario] requires that all new low-rise residential dwellings to have radon gas mitigation measures in place when applying for building permits,” Basmaji says. “This program has also been extended to industrial, commercial, and institutional (ICI) buildings with a few exceptions related to building type.”

Regardless of construction type, both Warkentin and Basmaji emphasize that testing is the only way to identify if radon is a problem.

Warkentin recommends visiting takeactiononradon.ca, a website that lists sources to purchase various test kits, including one-time use detectors that require lab analysis, and digital monitors that provide both short- and long-term data on a building’s radon levels. She also suggests becoming certified through the Canadian-National Radon Proficiency Program, a designation program developed in partnership with Health Canada, to offer radon mitigation, testing and training services to clients and homeowners.

“By being proactive and educating your clients on radon, even going to the extent of offering the service of testing/mitigating for radon as part of your building contractors, you are reassuring your clients that their safety is a top priority,” Basmaji says.

For more information, visit ipexna.com. 

Created by Amplify by Annex, in partnership with IPEX and HPAC Magazine.