Wind tunnel tests on scale model buildings as a means for studying ventilation and allied problems.

Wind tunnel test conducted on a scale model of a classroom show that, provided the test air speed is kept in excess of about 3mph, it is feasible to use models for predicting, with good accuracy, the air-flow conditions in and around full-scale buildings. In the case of low-pitch roofs the height of the stagnant zone set up as a result of flow separation occurring at the windward eaves of a building is influenced by wall height rather than by roof pitch. As a result of the absence of directed flow, roof ventilators and other ventilation openings situated within the stagnant zone will cause extraction of air from the building, not by direct action of the wind but by the differential pressures acting across them.