The ventilation of large and small rooms, as well as the design of the necessary equipment and its supply and exhaust ducts, present the engineer with a complex problem. It makes a difference whether the trailing edge angle is to be varied or whether smoke extraction is to be ensured in an underground garage in the event of a fire. The decisive factor is the level of detail required for the task at hand. What does the fan do and what does this mean for my task? Read on to find out how to find your way around this map.