Climate data analysis to assess resilience of wall assemblies to moisture loads arising from the effects of wind-driven rain

Abstract

In North America, and abroad, there currently exist standard test protocols for assessing the watertightness of wall assemblies and fenestration components although most of these methods are not directly related to expectations of in-field conditions as might be experienced by a wall assembly over its intended service life. How useful might such test protocols be to help determine the longevity of wall assemblies to future climate loads? Existing walls may, depending on their geographic location, be vulnerable to future climate loads and thus risk premature deterioration. For the design of new wall assemblies consideration ought to given to the non-stationarity of the climate and implications on the moisture loads on walls and the expected performance over the long-term. To permit assessing the resilience of wall assemblies to the effects of a changing climate as may occur in the future, and indeed, perhaps heightened moisture loads, one requires sufficient information on the watertightness of the assembly in relation to specified wind-driven rain loads and wall air-leakage conditions from which wall moisture retention functions could readily be developed. Such moisture functions are the basis of input of moisture loads to hygrothermal models and from which the expected long-term wall moisture performance can subsequently be derived. In this paper, a description is provided of the strategies used to analyze the WDR load for generating experimental input for a watertightness test protocol under development to assess resilience of wall assemblies to moisture loads arising from the effects of wind-driven rain in consideration of both historical climate loads and those as may arise from a changing climate.