Abstract
Over the years the ventilation demands in industrial plants have been increasing steadily with larger and more complex plants, increased heat input of automated production and service machinery, and greater emphasis on environmental control. Very few ventilation systems actually handle their rated air volumes. Components now are tested separately and under ideal conditions; however, they seldom deliver their rated performance when combined and under service conditions. Servicing of installed units is often rendered very difficult by designs to minimize space requirements or by inaccessible location. It is recommended that all specifications call for delivery of 100% of rated volume in the completed installation.