RPC produces a complete range of round and circular ducts plus all necessary fittings, including elbows, reducers, transitions and laterals. Circular ducts are available in diameters ranging from 50mm to over 3,000mm.
Rectangular duct and fittings can be fabricated to virtually any dimension specified by the customer, but is more expensive to manufacture / supply compared with the equivalent circular duct profiles. In some cases, turning vanes, splitters or stiffeners may be required to reinforce rectangular duct, particularly for vacuum applications.
GRP elbows in diameters up to 600mm NB are moulded in one piece with a continuous radius. This size range has a 1.5 diameter centreline radius. Standard elbows over this size are produced in a three-section metered construction with any desired centreline radius. Mitred elbows can be produced with a greater number of sections when specified by the customer. All elbows are produced with a smooth interior to eliminate air turbulence and assure long service life.
Square to round transitions can be designed and accurately fabricated to assure tight, leak-proof joints for connection to fans, heaters, blowers etc. These transitions are available in standard sizes or can be custom fabricated to meet individual customer requirements.
GRP reducers for use between different sizes of duct are furnished with a standard taper of 2.5 (D1 - D2). The diameter of the larger duct section should be used in determining correct wall thickness for the reducer.
Duct Supports and Hangers
GRP duct is typically recommended to be supported on 120° (min) saddles or hangers to avoid localised stress concentrations and point loads.
Corrosion-proof and weather proof throughout, high strength GRP stacks require minimal support because of their lightweight nature. These stacks have no longitudinal seams and are supplied in 6m and 12m sections. Fabricated with a bell-joint end (optional), they can be factory assembled before shipment or erected in the field without special equipment. RPC engineers are prepared to design stacks to meet specific operating conditions.
Standard GRP branch connections are available in 30°, 45° and 90° configurations. The stub is normally cut and bonded to the manifold or main by factory personnel, unless otherwise specified. Branch connections can be assembled in the field by RPC installation crews or by customer personnel.
Maintenance-free GRP weather caps are ideal for both corrosive fume ventilating systems and for industry-wide applications involving less severe industrial fumes. Offering proven resistance to the effects of weather, including hail and windstorms, these caps feature a special rigid construction that eliminates the need for guy-wires and other external support.
FRP dampers provide positive system control plus maximum resistance to severe corrosive attack. These units are standard adjustable dampers complete with quadrants and locking screws. Adjustment ranges from complete shut-off to full 90 degree opening.
Butterfly flow control, isolation or radial vane dampers provide positive system control, plus maximum resistance to severe corrosive attack. These units are standard adjustable dampers with locking handles, or motorised complete with PLC controllers. Adjustment ranges from complete shut-off to full 90° opening.
Furnished for both round and square duct systems, blast gates are recommended for use where relatively few adjustments are required. The gate fits snugly into the slot moulded into the GRP section. A convenient hand grip is provided to facilitate removal. Dampers are recommended where the system requires frequent adjustment.
Standard GRP flanges are fabricated to allow conventional connection to expansion joints, dampers and heaters, and for connection to tanks and vessels. They are integrally attached to the duct in the factory or can be site fitted to suit construction requirements.