Volume 8, Issue 3 (March 2011)

    Correlation Between Water Vapor and Air Permeability of Building Materials: Experimental Observations

    (Received 15 December 2009; accepted 17 February 2011)

    Published Online: 2011

    CODEN: JAIOAD

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    Abstract

    Two fundamental properties of building materials that influence the hygrothermal performance of building envelope systems are water vapor permeability and air permeability. The driving forces for water vapor and air transmission through building materials are, respectively, partial water vapor pressure and total air pressure differentials. The theoretical similarity of the driving forces would suggest the possibility of a relationship between water vapor and air permeability. During past two decades, researchers at the National Research Council of Canada—Institute for Research in Construction have compiled a database of measured air permeability and water vapor permeability properties of building materials commonly used in North America. This material properties database was examined to identify the degree to which air permeability and water vapor permeability of the building materials might be functionally related. The database was segregated into categories for different material types. An approximately linear relationship could, within some categories, be observed between water vapor permeability and air permeability. There were however approximately as many categories within which no relationship between the parameters was apparent as there were categories within which functional relationships between the parameters were apparent. Within categories where functional relationships were apparent, the form of the relationships generally depended on the mean relative humidity at which water vapor permeability was measured. In most cases, a definitive functional form of the relationship between water vapor permeability and air permeability could not be established.


    Author Information:

    Mukhopadhyaya, Phalguni
    Senior Research Officer, Institute for Research in Construction, NRC Canada, Ottawa, Ontario

    Batcheller, Devin
    Co-op Student, Institute for Research in Construction, NRC Canada, Ottawa, Ontario

    Kumaran, Kumar
    Principal Research Officer, Institute for Research in Construction, NRC Canada, Ottawa, Ontario

    Lackey, John
    Technical Officer, Institute for Research in Construction, NRC Canada, Ottawa, Ontario

    van Reenen, David
    Technical Officer, Institute for Research in Construction, NRC Canada, Ottawa, Ontario

    Normandin, Nicole
    Technical Officer, Institute for Research in Construction, NRC Canada, Ottawa, Ontario


    Stock #: JAI102924

    ISSN: 1546-962X

    DOI: 10.1520/JAI102924

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    Author
    Title Correlation Between Water Vapor and Air Permeability of Building Materials: Experimental Observations
    Symposium , 0000-00-00
    Committee C16