b'The performance of these systems is interconnected. Given their complexities, these systems can negatively interfere with each other if not designed, coordinated and built with due care. To achieve both energy efficiency and radon control, a comprehensive, whole-building approach is required, involving multidisciplinary efforts to design systems that synergize, rather than interfere with each other. 3. METHODS FOR RADON MITIGATIONA combination of three measures isFIGURE 2. RADON CONTROL OPTIONS ACCORDING TO CAN/CGSB-149.11-2019 AND CAN/CGSB-149.12-2017.required to control radon in buildings:3.1.Physical Barrier barrier is also critical, such as use ofdisplacement and conditioning to specialty tapes at laps, transitionsmaintain acceptable radon levels, The barrier method relies on the phys- to other materials, penetrations andeven with heat recovery.ical properties, installation and conti- termination details.nuity of the soil gas and air barrier toThe above three methods in combi-stop the entry of radon into interior spaces. This approach is heavily3.2.Soil Depressurization nation provide the best outcome for Radon mitigation systems relyradon mitigation without competing dependent on installation quality. Therefore, even with robust mate- on an air-permeable layer such aswith energy efficiency goals.rials and good installation practice, acrushed gravel or air space formed with channelled rigid insulation atphysical radon barrier alone may notbelow-grade floor assemblies. The4. 2024 BRITISH COLUMBIA be reliable as the sole radon controlair-permeable layer is connected to aBUILDING CODE (BCBC) measure. Additionally, the barriervent pipe, which induces a negativeREQUIREMENTS may be compromised as a result ofpressure on the soil to pull radon natural building settlement when new4.1. Part 9 away into the atmosphere, either service penetrations are added to thepassively by stack effect or activelyThe latest BCBC released in March building, or if modifications are madeusing a fan.2024 includes changes related throughout the buildings life. to radon considerations and the 3.3.Mechanical Dilutionremoval of the radon risk map TableMechanically balanced ventila- C-4 in Appendix C. Now require-Most radon mitigation guides refer-ence a six-mil polyethylene sheet astion dilutes indoor air pollutantsments pertaining to radon barriers, the minimum required material forby replacing the indoor air withsubfloor mitigation systems and an effective soil gas barrier to preventoutdoor air, thereby diluting radonrough-ins apply across the province. diffusion. However, often thickerconcentrations. In buildings withSections of CAN/CGSB Standard or more tear-resistant materials areabsent or poor physical radon149.11 are referenced regarding the favourable to withstand damage frombarriers and under-slab soil depres- design and construction of radon construction activity, e.g. 10-mil orsurization systems, this approachmitigation systems, e.g. a passive 15-mil polyethylene or polyolefin.can lead to energy cost penalties,vertical radon stack that runs upward Keen attention to detailing of theas large volumes of air will requirethrough the inside of the building STRATEGIES FOR THE BUILT ENVIRONMENTCOMPLEX QUESTIONS ANSWERED.Optimize the quality, value, and performance of your projects and facilities with Rimkus.rimkus.comConsultants. Experts. Innovators. 866-891-9869SPRING/SUMMER 2024 21'