ABSTRACT
This chapter discusses the effect of the wind and how and at what rates ventilation will take place without the need of mechanical ventilation will be discussed. Air flow velocity through window openings, due to pressure effect of the wind, depends upon and varies directly with wind speed. For low-silhouette buildings, 10-15 ft in height, wind speed is the chief force in natural ventilation. Natural ventilation should always be designed on the basis of at least a 2-mph wind, but more often a 4-mph wind is considered. To compute the flow due to temperature difference, when inflow and outflow openings are of unequal area or resistance, there has been developed the important concept of the neutral zone. Since windows are most often used for natural ventilation, it is quite normal that more should be known about the influence of the different types of windows on the flow of air.
