Specify galvanized steel ductwork and plenums. Support exposed ducts with rods bolted to duct angle stiffeners or to steel angle or channel cradles. Support vertical risers at each floor level with intermediate guide support midway between floor. Provide factory-fabricated hardware for manual dampers, plenum doors and access doors as manufactured by Vent Fabrics or DuroDyne. Provide grease hood exhaust ducts with welded grease-tight seams and joints.
Pitch duct back to hood and provide for drainage.
Outdoor ducts shall be sealed watertight and top of duct shall be sloped to prevent water pooling. Provide capped instrument test holes on each side of heating coils, fans and units with duct connections. Location shall be visible and accessible for taking accurate measurements of static pressures and air velocities. M. Dampers 1. Show accessible manual volume dampers at major divisions in all duct systems to permit balancing of air quantities.