A Moisture index approach to characterizing climates for moisture management of building envelopes

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Conference9th Conference on Building Science Technology: 27 February 2003, Vancouver, British Columbia
Pages383398; # of pages: 16
Subjectmoisture index, driving rain, moisture reference years, climate classification; Moisture performance
AbstractPremature failures of building envelopes in some North American locations appear to be climate related. An IRC-led research consortium called MEWS (Moisture Management of Exterior Wall Systems) developed a method using hygrothermal modelling to identify locations where walls may experience moisture related problems. The method classifies climates by a Moisture Index (MI) based on wetting and drying potentials. Responses of various wall systems to the climatic inputs of Moisture Reference Years (MRY, selected according to their MI) were examined for seven North American locations spanning the MI range of climate severity. The study linked the likelihood of failure to construction deficiencies allowing excessive amounts of rain into the wall, and generally confirmed a direct relationship between hygrothermal response and MI.Application of MI and MRY did, however, reveal anomalies for some climates. MI can post warning flags, but hygrothermal modelling is required to explore potential problems in depth.
Publication date
AffiliationNRC Institute for Research in Construction; National Research Council Canada
Peer reviewedYes
NRC number45704
NPARC number20378565
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Record identifiere4a056e6-73ea-47da-89cb-6ea52f433575
Record created2012-07-24
Record modified2016-05-09
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