21. They are available with either fixed or movable louvers . 22. The most common method of controlling the louvers is the balanced swell pedal. 23. Some modern louver systems serve to improve indoor daylighting. 24. In industrial facilities such as steel power plants, louvers are very common. 25. A wider arena and faster louver speed cause a faster, tighter vortex. 26. Roll control was by differential actuation of the wing-fan exit louvers . 27. Most earlier models also had louvers near the bottom of each side panel. 28. One example was the return of the bonnet louvers . 29. Lining the fa�ade of the David Brower Center are fixed exterior aluminum louvers . 30. These louvers block the direct sun and minimize heat gains within the building.
