Get ductwork venting, fittings and caps at Grainger! Round, square and perforated diffusers help disperse air from ductwork in ceilings or walls. Motorized fire and smoke dampers feature factory-installed actuators that can force damper blades to close in emergency fire and smoke situations. Various diameters of gas vent pipe fit into separate firestop support plates that can act as passive fire prevention. Grease duct and hi-temp access doors can help you easily gain entry for inspection and cleaning. Trust Grainger for all your ductwork venting, fittings and caps.