Abstract: A critical area recirculation and exhaust system for a room operates in a normal operating mode where fresh air is delivered from an air handler through a diffuser and returned to the air handler through a room return duct. In a selected isolation operating mode, a fan filter unit is activated to draw contaminated air from the room through one or more filters and to expel the filtered air through the diffuser and through an exhaust air duct to create an increased air change rate and a negative pressure in the room.

Abstract: Pattern controllers located in discharge slots of an active beam comprise a series of planar paddles hinged on an axis disposed at an angle to the planar surface of a side of the discharge slot thereby producing discharged air displacement in both the horizontal and vertical directions when the paddles are rotated.

Abstract: A ceiling panel clip to engage the grid structure of a drop ceiling and thereby hold panels of a drop ceiling in place.

Abstract: An adjustable terminal basket with lightweight horizontal diffuser grille is mounted in the floor of an occupied space for delivering conditioned air from an under floor air plenum to the occupied space above the floor. The modular floor terminal basket regulates the air passing through the terminal, and the lightweight horizontal diffuser grille diffuses the conditioned air along the floor of the occupied space. The lightweight horizontal diffuser grille is constructed with a top and bottom plate with hollow support pillars between the plates and with reinforcing ribs adjacent the center of the diffuser grille.

Abstract: An adjustable terminal basket with lightweight horizontal diffuser grille is mounted in the floor of an occupied space for delivering conditioned air from an under floor air plenum to the occupied space above the floor. The modular floor terminal basket regulates the air passing through the terminal, and the lightweight horizontal diffuser grille diffuses the conditioned air along the floor of the occupied space. The lightweight horizontal diffuser grille is constructed with a top and bottom plate with hollow support pillars between the plates and with reinforcing ribs adjacent the center of the diffuser grille.