This paper is a continuation of previous research carried out to improve the hygrothermal analysis capabilities of the readily available HAM-Tools building simulation software. HAM-Tools is an open source library of Simulink models specifically constructed for thermal system analysis in building physics including one-dimensional heat, air, and moisture (HAM) analysis through building envelope components and ventilated spaces. The previous study was intended to improve the program by adding a wind-driven rain module using a semi-empirical model from ASHRAE 160P in the hygrothermal analysis. Comparison toWUFI simulation results was used to verify the wind-driven rain module in HAM-Tools. However, the previous study did not account for the difference in moisture transport mechanism and calculation between the two programs. HAM-Tools uses suction pressure differential as the driving force and the hydraulic conductivity while WUFI uses moisture content difference as the driving force and liquid diffusivity for liquid transports. In this study, the verification procedure for the wind-driven rain module was corrected. Simulation results using HAM-Tools were compared to results fromWUFI simulation for different weather data and wall assemblies and to field measurements taken under coastal climate of British Columbia. The comparison with WUFI results and field measurements indicated that the newly designed HAM-Tools wind-driven rain module is performing properly.

Presented at Thermal Performance of Exterior Envelopes of Whole Buildings XII, December 2013