A Moisture Index to Characterize Climates for Building Envelope Design

Abstract

/npsi/ctrl?lang=en http://nparc.cisti-icist.nrc-cnrc.gc.ca/npsi/ctrl?lang=fr Access and use of this website and the material on it are subject to the Terms and Conditions set forth at http://nparc.cisti-icist.nrc-cnrc.gc.ca/npsi/jsp/nparc_cp.jsp?lang=en NRC Publications Archive Archives des publications du CNRCThis publication could be one of several versions: author's original, accepted manuscript or the publisher's version. / La version de cette publication peut être l'une des suivantes : la version prépublication de l'auteur, la version acceptée du manuscrit ou la version de l'éditeur. For the publisher's version, please access the DOI link below./ Pour consulter la version de l'éditeur, utilisez le lien DOI ci-dessous.http://dx.doi.org/10.1177/109719603036210Journal of Thermal Envelope & Building Science, 27, 2, pp. 151-178, 2003-10-01 A Moisture index to characterize climates for building envelope design Cornick, S. M.; Dalgliesh, W. A. with lab testing and hygrothermal modeling to understand and deal with these problems. The method proposed in this paper was used in MEWS to 1) characterize climate with respect to the risk of moisture related building envelope problems, 2) select locations of interest for a detailed hygrothermal parametric study, and 3) to select moisture reference years for the parametric study (not covered in this paper). This paper describes a method proposed for mapping North American climatic regions according to moisture loading on one hand, and the potential for drying on the other. The composite Moisture Index can be used either with hourly records or summary data, and shows promise for application to specific problems, such as decay or corrosion, depending on the nature and mechanisms of the problem being investigated.Keywords: wall moisture; annual rainfall; climate classification; rain wetting; drying potential; moisture index; driving rain; directional driving rain index; decay hazard; Review Approaches to Climate Classification for ConstructionThere are several different schemes for classifying the world's climate, most of them possessing genuine merit. Almost all of the schemes of climate classification have subdivisions and boundaries partly based upon temperature and rainfall parameters which are not meaningful in themselves, but have significance in terms of some non-climatic feature, such as vegetation or human habitability. If one disregards non-climatic phenomena, it is difficult to provide meaningful temperature-rainfall limits of climatic types. The majority of classification schemes, therefore, are of an applied character. One basis for grouping climate schemes is to divide them into genetic (concerning origin) and empirical types. In genetic classifications an attempt is made to group climates into the causative factors (e.g. air masses, wind zones) that may be responsible for them. In empirical classifications, origin is discarded as an organizing principle, and observation and experience provide the essential elements for climatic differentiation. The Köppen cla...

Estimation of building components' exposure to moisture in Greece based on wind, rainfall and other climatic data

“…As cited by Cornick and Dagliesh (2003), analyses have revealed that the use of average annual data instead of average hourly data for the calculation of the annual driving rain index might lead to a severe underestimation of the exposure levels (up to 40%). Therefore, the use of average hourly data is considered to provide more reliable results than the use of daily data.…”

“…This attempt is based on the calculation of a moisture index. The index used is the one proposed by Cornick and Dagliesh (2003). This index comprises the calculation of a wetting index and a drying index.…”

“…), an indication of the impact of the urban environment to the estimated exposure levels is acquired for Thessaloniki. It is generally accepted that the use of data referring to smaller intervals for the calculation of annual driving rain leads to the derivation of more accurate results (Cornick and Dagliesh, 2003;Blocken and Carmeliet, 2008). Average daily wind speed and total daily precipitation for the city of Thessaloniki were available for all the 24 years studied (1980-2005, 1991 and 2004 excluded) (Université de Thessaloniki, 1981-2006).…”

Moisture content prediction of rain-exposed wood: Test and evaluation of a simple numerical model for durability applications

“…boundary moisture fluxes on the same form as equation (7). By assigning a large value to the surface transfer coefficient and changing weq for wwet, the Neumann-type condition becomes analogous to the condition given by equation (8). It should be noted that (8) applies exclusively to boundaries which are exposed to rain.…”

“…Empirical functions of weather parameters are often used to predict material climate when estimating the service life of timber [6][7][8]. However, empirical models are not always related to actual material properties.…”