Hand lay–up made pipes, usually for small diameters, have a high content of resin and therefore are recommended for highly corrosive fluids. They can be fully made in FRP or dual–laminated (thermoplastic as PVC, PP, PVDF, FEP, C–PVC, or others inside and FRP outside).
Pipes made by filament winding, a semi-automatic manufacturing system, have a higher content of fiberglass than hand lay–up pipes. Therefore, they have better mechanical resistance, sacrificing part of their chemical resistance. These kinds of pipes can also be used for corrosive fluids if their chemical barrier is dimensioned with the necessary thickness and the appropriate type of resin or if they have an inside liner of an appropriate thermoplastic (dual laminate).
Bell & Spigot with rubber rings
These types of pipes are usually made by filament winding system and, therefore, have a greater fiberglass content than hand lay–up pipes with better mechanical resistance. These kinds of pipes can be used for corrosive fluids in the same conditions as generic filament winding pipes. Leak–proof is guaranteed by rubber rings, and they are recommended for water or very little corrosive fluids pipelines, buried in almost all cases.
Bell & Spigot with rubber rings and locking tape
These types of pipes are usually manufactured by Filament Winding. They typically have a corrosion barrier of 1.5 mm thick, although it has to be calculated depending on the fluid to transport. The tightness of the joints is achieved by elastomeric O–rings that are suitable for water lines or chemically less aggressive fluids. It’s usually a pipe for immersion, like underwater emissaries, wherein the locking tape or retainer prevents the tubes from disengaging from each other.
Pipes with inert charge
Inert charge pipes are made through a filament winding procedure. They are especially recommended for water pipelines or for slightly aggressive fluids handling. The reinforcing layer contains an inert charge (usually sand) to increase its hoop stiffness without increasing its final cost. They are manufactured with bell & spigot joints (with or without a retainer) and for butt & wrap joining.
Filament Winding pipelines with bell & spigot with rubber rings and locking tape, specially designed to be installed underwater (both saltwater and freshwater). These pipelines are also prepared for butt & wrap joints if needed.