Radon Risk Assessment and Mitigation & BOMA BEST Certification

 What is Radon?

Radon is an invisible, tasteless, and odorless radioactive gas produced via the natural decay of subsurface uranium. Radon gas can migrate through bedrock, soil, and groundwater on its way to the surface. When released directly into the atmosphere, radon gas becomes diluted to concentrations that do not pose any health concerns. However, when it enters buildings, radon gas may accumulate in indoor air, potentially leading to high and harmful concentrations. All homes contain some radon, but concentrations vary based on geology, natural preferential pathways, and building features.

 

Radon gas can infiltrate into buildings directly through gas permeable materials such as concrete slabs/foundations and standard plastic vapour barriers or via preferential pathways such as cracks in floor slabs and foundation walls, gaps around utility entry points, empty spaces in walls, construction joints and/or seams, floor drains and sumps, and the water supply system. Radon gas tends to accumulate most in closed and/or poorly ventilated spaces, with the highest levels typically observed in crawl spaces and basements.

 

Health Risks and Testing

Radon gas exposure can pose significant long-term health risks. Radon is the leading cause of lung cancer among non-smokers, accounting for about 16% of cases and causing over 3,000 deaths annually in Canada. Risk increases with higher exposure and is compounded by smoking. The current Canadian guideline (Health Canada) for radon is 200 becquerels per cubic meter (200 Bq/m3).

 

While radon risk maps exist, they provide only broad regional estimates and cannot predict levels in a specific building. Testing is the only reliable method and can be done with do-it-yourself kits or through a certified professional accredited by the Canadian National Radon Proficiency Program (C-NRPP). As indoor radon levels can vary significantly over time, Health Canada recommends long-term testing during the heating season for at least 91 days. Short-term tests give quicker results but are less accurate. Certified professionals can assess the building, determine the best testing location(s), and provide guidance on results.

 

Radon Mitigation

If radon exceeds 200 Bq/m³, mitigation is recommended. If strong enough, air handling systems can potentially reduce radon when properly calibrated; however, they are not specifically designed for this purpose and are not typically equipped with an alarm to warn occupants when the unit is not functioning correctly. It is important to note that air handling systems not at equilibrium (i.e., those creating negative pressure within a room/building) may increase indoor radon levels by exasperating the chimney effect thereby drawing in more soil gas. The most effective method is Active Soil Depressurisation (ASD), where a fan mounted on a pipe that extends from under the building foundation draws in radon gas from beneath the home and expels it to the exterior, either through a side wall or the roof. This method creates a negative pressure differential between the air within the building and the soil underneath the foundation, thereby further reducing the amount of radon entering a home.

 

A C-NRPP certified professional will select and design the most suitable radon mitigation system (RMS), choose the optimal location(s), and confirm effectiveness with post-installation testing. ALL-TECH Environmental Services Limited has CNRPP-certified professionals to conduct radon assessment, and RMS design and installation/verification.

 

Radon and BOMA BEST Certification

Individuals looking to transition to more sustainable building operations and obtain certification can do so under the BOMA BEST environmental assessment and certification program for existing buildings.

 

Radon risk assessment contributes up to 3 points under the Indoor Air Quality (IAQ) and Hazards category. To obtain all 3 points, the following requirements must be met:

  • Conduct radon testing within the building in accordance with all applicable testing conditions and locations.

  • Test occupied areas for at least 91 days during the heating season.

  • Use C-NRPP-approved devices and laboratories.

  • Have results certified by a C-NRPP professional or similar certification body.

Alternatively, one point can be earned by reporting the percentage of homes with high radon levels in the surrounding region. Full details are available in the BOMA BEST Field Guide, available at: https://bomabestfieldguide.org/field-guide-for-sustainable-buildings/i6-3-radon-risk-assessment/.

BOMA NBPEI