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Radiat Environ Biophys (2009) 48:153158 DOI 10.1007/s00411-009-0212-5
ORIGINAL PAPER
Radon diffusion coefcients of vapour barrier membranes used in Canadian building construction
Jing Chen Jim Ly Eveline Schroth Stan Hnatiuk Etienne Frenette Marie-France Blain
Received: 5 November 2008 / Accepted: 22 January 2009 / Published online: 12 February 2009 Springer-Verlag 2009
Abstract Vapour barrier membranes are often used as soil gas retarder in building construction. While vapour permeance characteristics of these membranes are well known and specied in Canadian standards, their radon diffusion coefcients are yet not available. This study provides test results of radon diffusion coefcients for 10 vapour barrier membranes commonly used in Canadian building construction.
Introduction
Based on more recent scientic information [Darby et al. 2005; Krewski et al. 2005], Health Canada recommended the lowering of the Canadian Radon Guideline from 800 to 200 Bq/m3 [Health Canada 2004]. This lower guideline, with its extended scope of protection against indoor radon exposure, was ofcially announced in June 2007 [Government of Canada radon guideline 2007]. It now includes the following new recommendation: The construction of
new dwellings should employ techniques that will minimize radon entry and will facilitate post-construction radon removal, should this subsequently prove necessary. This new recommendation has raised questions as to whether current acceptable solutions for soil gas control in the National Building Code of Canada 2005 [National Research Council Canada 2005] are adequate to protect occupants from the ingress of soil gas radon.
The National Building Code of Canada includes a paragraph on soil gas control. The Code identied radon as one pollutant often found in soil gas. As indicated in the code, Floors-on-ground serving all types of occupancies other than garages must be constructed to reduce the potential for entry of radon or other soil gases. In most cases, this will be accomplished by placing0.15 mm polyethylene under the oor. This recommendation was based on the former Canadian Radon Guideline of 800 Bq/m3.
Polyethylene membranes are often used as vapour barriers in building construction. Soil gas is any gas emanating from the soil, including radon, methane and water vapour. In many parts of Canada, polyethylene sheeting is normally placed on top of the gas-permeable granular layer under the foundation to help prevent the soil gas and moisture from entering the...