Moisture permeability data presented as a mathematical relationship

A detailed statistical analysis is presented of the correlation between moisture permeability and relative humidity based on experimental data obtained by the authors and a variety of other investigators using standard gravimetric measurement methods. In total, five proposed mathematical formulations are examined for five different types of material commonly used in building construction. The suitability of each formulation is investigated using non-linear regression techniques including an analysis of collinearity and relative standard error. This statistical approach allows the best functional form of equation for describing the variability of moisture permeability with relative humidity to be identified for building materials. A database covering a total of ten materials is then presented on the basis of this equation.