<strong>Types of Ventilation Designs:</strong><br /> 1) With a single-sided, high level opening, ventilation is generally effective to room depths of up to 10 feet (or less than two times the room height).<br /> 2) When using single-sided, high and low openings, ventilation can be effective up to 30 feet (or less than 2.5 times the room height).<br /> 3) If a building space has cross ventilation with windows on two opposite sides, the ventilation can be effective up to 40 feet of the room depth (or five times the room height).