The Task Group (TG) on Radon, chaired by Kyna Low, met to review the July 22, 2025 meeting record, a proposed code change, and NRC research. CHBA followed up on concerns about inconsistencies between radon diagrams in the 2020 Code and the Part 9 Illustrated Guide. Staff confirmed the diagrams were reviewed but cannot be updated until the 2030 edition. CHBA emphasized the need to correct the Illustrated Guide sooner due to field confusion, including capping of intake pipes. Staff advised raising concerns with the Canadian Board for Harmonized Construction Codes.

Codes Canada presented a proposed change to include active radon mitigation systems in Part 9. If approved quickly, provinces and territories could possibly adopt it alongside existing 2025 passive stack requirements. Clearance details are pending, and the TG will review CGSB radon mitigation standards. CARST raised concerns about unqualified installers installing active systems. CHBA stressed the importance of including options, as the lack of flexibility could hinder adoption.

NRC presented research on how active systems affect home depressurization. The next step is to compare results with combustion appliance limits, though responsibility for this work remains unclear. CHBA recommended revisiting pre-2010 NRC or CMHC research that informed the 2010 NBC’s separate radon and depressurization requirements.

Staff also shared a list of potential future research topics for discussion at a later meeting.

The agenda package can be found below.

For any questions, please contact Jack.Mantyla@chba.ca