Driving Rain Test Facility

The Driving Rain Test Facility is used to investigated the water tightness of tiled roofs and shingled walls. The test specimen - width 2 m and length 3 m - will be covered by the tiles or shingles provided by the client. It is exposed to a combined rain and wind action. The pitch angle may be adjusted relative to the horinzontal axis of the wind tunnel.

Water penetration under a tiled surface is mainly due to the wind stagnation at the lower edges of the tiles. The corresponding stagnation pressure forces the water flowing down the tiles ord shingled surface into the batten space. The intensity of the rain and wind action may be quantified according to LACEY as driving rain index (DRI). The validity of the driving rain index has been developed by LACEY in the 1970ies and was confirmed by CHOI in Canada in the 1990ies.