b'HEALTH & SAFETYRADON 101 UREWHY BUILDERS NEED TO ENSURE ADEQUATE MITIGATION MEASURES ARE IN PLACE FROM THE GET-GO By Matthew BradfordHEIGHTENED EXPOSURE TOprovince is slated to adopt stricter radonright at the start of a project that will radon gas can pose significantregulations for new construction in theinhibit radon entry in order to simplify health and safety risks and constructioncoming years. Most provinces across themitigation requirements down the road. professionals need to be aware ofcountry have adopted a requirement for aOne of the first mistakes constructors mitigation measures they can take toradon mitigation rough-in as part of theirmake is concluding they dont need lessen its impact on building occupantsbuilding code, and Ontario will join themradon-resistant construction in new down the road. This past spring, TCAin early 2020, Innes reports.construction, or they dont think their held an information session on radonradon resistant design to completion, to address the issue, and some of theRadon can enter buildings of all typessays Bruce Decker, senior indoor discussion points are reviewed here. via openings of any size in the envelope,environmental specialist with BGIS. That including sump pits, cracks in the slab,approach can lead to thousands of dollars Radon is a naturally occurring radioactiveand cold joints where the slab meetsin remediation work down the line.gas that is colourless, odourless andthe wall. The mechanism which drives tasteless. It is produced from theradon into buildings is based on pressureDecker, who joined Innes and Cryer breakdown of uranium in soil, rock anddifferentials between [whats] under andfor the TCA presentation, adds that groundwaterthe gas releases radonabove the building slab, explains Scotttesting the soil for radon before starting decay products (RDPs) which cling toCryer, national practice leader, Radon,construction is not always a reliable lungs and decay into radioactive alphaPinchin Ltd., and another presenter attechnique: This method has been shown particles that can contribute to lungthe TCA event. Buildings typically have ato be filled with challenges and does not cancer. It is imperative that buildersrelatively higher pressure below the slabprovide confidence that the building wont take steps to identify and mitigate thewhich drives radon into a building. Whenhave high radon.presence of radon during work on bothbuildings are mitigated for radon, the new and existing buildings. While traceintent is to reverse that trend and create a amounts of radon are present in thenegative pressure under the slab relativeAnother misconception is that lack of air we breathe, exposure to elevatedto the pressure which exists above radon in the area means there is no need concentrations needs to be avoided. Itsthe slab.to test. Innes says this couldnt be further a Class A carcinogen that is the leading cause of lung cancer after smoking, says David Innes, director of sales with RadonNUMEROUS PROVINCES HAVE ALREADY PUT RELIABLE MEASURESEnvironmental Management Corp., one of the presenters at the TCA event.IN PLACE TO MITIGATE RADON GAS, INCLUDING MANDATORY TESTING, There is limited legislation to date that mandates what concentrations of radonPUBLIC EDUCATION AND RADON MEASUREMENT GUIDELINESare acceptable to building occupants in the workplace. Under the Canada Labour Code, the enforceable limit for occupant exposure is set at 800 BecquerelsThere are techniques to manipulate thesefrom the truth: We often see one house per cubic metre (Bq/m), which ispressures in new and existing projects.in a neighbourhood test high and the one significantly higher than Health CanadasHVAC systems can be used to pressurizebeside it test low. This can be the result of recommended action level of 200 Bq/ or ventilate buildings to control radonsub-grade cracks and fissures coming up m. That said, Labour Canada is planninglevels, while sub-slab depressurizationunder one house and carrying the radon to harmonize its standards with Healthsystems can be installed to exhaust radonup under that house. The earths crust is Canada later this year. gas from under a slab to the exterior ofalso moving constantly, so even if you test the building. Other strategies at the timelow today, it is a good idea to test every Numerous provinces have already putof construction include using passivetwo to three years.reliable measures in place to mitigatesystems (versus active), ensuring all vital radon gas, including mandatory testing,components are sealed; using high-quality public education and radon measurementgravel; and working with radon mitigationConsidering the risks and incoming guidelines. Several Ontario jurisdictionsspecialists in the design phase.regulations, the message is clear: its have followed suit with respect toessential that the citys construction implementing radon mitigation measuresThe underlying message is that it isindustry make radon mitigation a priority at time of construction. As well, thebeneficial to incorporate measureson all building projects.BUILDERSDIGEST Quarter 2 201923'