SENSITIVITY OF BUILDING COMPONENTS' MOISTURE RESPONSES TO THE ATMOSPHERIC MOISTURE LOAD

This article aims at formulating a necessary level of detail in models for the atmospheric moisture load for attaining an accurate assessment of building components’ moisture responses. Simulated moisture responses of a ceramic brick outer leaf and rendering are compared for different models for the two key parts of the atmospheric moisture load: wind-driven rain and evaporative drying. It is shown that a constant wind-driven-rain coefficient yields only slight loss of accuracy, but the determination of the constant value has to take the influences of variability with rain intensity and wind speed and of temporal averaging into account. For the evaporative drying it is shown that the variations of the surface moisture and heat transfer coefficients with wind speed, and their overall order of magnitude, heavily influence the moisture responses. While most of the analysis is illustrated with the ceramic brick results only, it is noted that similar conclusions result for the slightly less sensitive rendering.