December 1, 2010 - Ottawa, Ontario
Canadians buying homes built to meet the 2010 National Building Code provisions will face less risk of radon exposure, thanks to new protective measures.
Radon - a radioactive gas you can't see, smell or taste - is found at varying levels in most homes in Canada. It is formed by the breakdown of uranium, a natural radioactive material found in soil, rock and groundwater. When radon is released from the ground into enclosed spaces like basements, it can sometimes accumulate to high levels and become a health risk.
Radon is the second leading cause of lung cancer after smoking. In 2006, an estimated 1,900 lung cancer deaths in Canada were due to radon exposure.
Health Canada
In 2007, Health Canada issued a new guideline for exposure to radon in indoor air. The old radon guideline had been 800 becquerels per cubic metre (Bq/m³), while the new guideline sets a maximum acceptable exposure of 200 Bq/m³. This level is in line with limits set by the Environmental Protection Agency in the U.S. and most other countries.
The 2005 edition of the National Building Code already contained basic measures to protect against radon and other soil gases seeping into buildings, such as soil gas barriers. Although these basic measures remain largely unchanged, they now apply to all new homes.
What's new is that the 2010 Code reflects the revised Health Canada guideline and provides for additional mitigation measures. For example, engineers and designers must now consider radon protection in the design of larger buildings.
"Once radon is found to be a problem in a home, it's often too late and too costly to put in a system to remove it," says Frank Lohmann, a technical advisor in the Canadian Codes Centre at NRC.
As it happens, Lohmann found excessive levels of radon in his 30-year-old home in Chelsea, Quebec - an area known for high radon levels. But, given his line of work, he knew exactly what to do. Lohmann has installed a subfloor depressurization system that sucks radon out from underneath the concrete basement slab.
The 2010 National Building Code is one of three national model codes recently published by NRC, the other two being the National Fire Code and the National Plumbing Code. These model codes are developed through broad-based consultation and consensus among all sectors of the construction industry - regulatory authorities, designers, builders, suppliers, researchers and the general public.
The national model codes published by NRC are model codes only, given that the provinces and territories have jurisdiction over construction. Some provinces/territories adopt the national model codes without change while others adapt them to suit regional needs before publishing them as their own codes.
Not only does NRC play a crucial role in providing Canada's national model building codes, but it also conducts research to increase safety in buildings. For example, several NRC institutes are working together to develop new sensor technology to detect common indoor contaminants, including radon. The NRC Institute for Research in Construction is responsible for the specification, testing and validation of the sensors within the context of building ventilation strategies and control.
