PRESSURE-EQUALIZED RAINSCREENS - A STUDY IN THE FREQUENCY-DOMAIN

The pressure-equalized rainscreen approach to wall design is becoming more prevalent in Canada. This paper describes a theoretical and experimental study of the pressure-equalization in rainscreen walls which was undertaken to improve the understanding of several design parameters. Primary facto rs which control the pressure-equalization are the leakage of the air barrier, the aerodynamic damping introduced by the venting in the rainscreen, and the spatial nonuniformity of the steady and fluctuating exterior pressures. This paper discusses each of these via the results of theoretical models, wind tunnel experiments, and full-scale experiments on two separate rainscreen designs. The effects on pressure drop across the rainscreen of changes in venting area and configuration, air barrier leakage, cavity volume and compartment size are all considered.