ABSTRACT
A comprehensive multi-institutional project on ventilation drying in screen-type enclosure wall systems, funded largely by ASHRAE, was recently completed. The project involved laboratory testing, field testing, and computer modeling. This paper presents the results of one test program. Three metal cladding panels with different sheathing membranes were tested under different climate conditions. The focus of the study was on the nature and extent of ventilation drying and the influence of the sheathing membrane. Ventilation wetting, a topic that has stimulated much discussion, was observed in the summer and high sun test and within a daily cycle both wetting and drying occurred. However, in all these tests the overall effect was clearly drying. This finding is important in that it demonstrates that under certain climatic conditions short periods of ventilation wetting can occur in the wall system but the overall performance is still drying.
