Author: Keith Woolard
Last saved by: Canale, Claudia
Company: Microsoft

SBTD: Square Dish-style
The damper shall be Camfil model SBTD-series, dish style isolation damper. Damper shall be adequately reinforced to withstand a negative or positive pressure of 15" water gage.  Damper shall be manufactured from 14 ga. and 11 ga. T-304 stainless steel sheet metal.  The damper shall have a 20" (nominal) T-304 stainless steel dish shaped disc with a knife-edge that seats against an 11 ga. T-304 stainless steel frame with a solid membrane silicone gasket.  This creates a gasket-to-knife edge seal.  
Damper shall be factory equipped with a manual actuator.  Actuator shall be equipped with a hand wheel.  Actuator shall be a quarter-turn manual worm geared operator.  Actuator housings and covers shall be cast iron, worms shall be heat-treated carbon steel, worm wheels shall be cast ductile iron, input shafts shall be carbon steel, shaft and worm seals shall be BUNA-N rubber, housing to cover seals shall be impregnated cellulose fiber, bushings shall be oil impregnated copper nickel steel alloy.  The actuator shall be of sufficient capacity to operate the damper under all conditions, and to guarantee tight close-off of the damper against all system pressures encountered.