A Triple Casement is a Casement window with three sash with two that operate
inside a frame while the center one is fixed and serves as a picture window. Just as in a Pair Casement one operable sash swings on its left while the other swings on its right. A Triple Casement can have sash that swing in or out. They can use a crank mechanism to swing out or they can be butt hinged to swing in or out. The locking mechanism is based on the operating mechanism.
