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The observation of wind pressure acting on the wall and floor of a full-scale building model under cross ventilation was carried out. The measurement of air flow was also undertaken, and the existing prediction theory of the air flow rate, namely the orifice flow equation, including the discharge coefficient, was evaluated for its accuracy. At the same time, a method of predicting the discharge coefficient has been proposed and tested.

Mechanical devices such as exhaust fans and air handlers interact strongly with natural infiltration. In the past, the effects of mechanical systems have either been treated separately from those of natural infiltration or have been combined using simple models. This paper extends the theory of the interaction of unbalanced mechanical systems with stack-driven infiltration. The effects of leakage distribution and the flow exponent on fan efficiency are discussed. A simple model for combining the two effects is presented and compared with two previously proposed models.

Natural ventilation of dwellings is commonly applied, especially in mild and moderate climates. The disadvantage of natural ventilation is the poor control of both flow directions and flow rates within the ventilated building. To improve control, theuse of mechanical exhaust is often recommended. Though this may improve total ventilation, the ventilation of separate rooms often is insufficient still.