Fiberglass composite pipe

At the 2013 Offshore Technology Conference, Joie L. Folkers of National Oilwell Varco Fiber Glass Systems presented a paper illustrating the difficulties associated with prescriptive rules (Folkers 2013). He used the example of fiberglass-composite pipe. The following is extracted from his presentation. 

The storage and transfer of raw chemicals requires special considerations relative to the equipment that come into contact with epoxy resins. Carbon steel is generally satisfactory for pipe and tank construction and will not rust beneath the epoxy resin. Rust occuring above the level of the epoxy and accidentally introduced into the resin may be removed by filters. Epoxy coated steel pipe, aluminum or stainless steel pipe, or epoxy fiberglass composite tubing is used to prevent rusting downstream of the filter. 

Example 2.4 Estimation of heat flow through a composite wall with constant thermal conductivities A pipe with an outside diameter of 10 cm and a length of 110 m is carrying hot fluid. The pipe is insulated with 0.5 cm thick silica foam and 10 cm thick fiberglass. The pipe wall is at 120°C and the outside surface of the fiberglass is at 30°C. Estimate the heat flow in the radial direction of the pipe. The thermal conductivities of silica foam and fiberglass are 0.055 and 0.0485 W/(m K), respectively. 

Corrosion-Resistant Binder for Fiberglass Composites. A second application of furan resins is as a premium, corrosion-resistant binder for fiberglass for fabrication of FRP structures for the chemical process industry. Structures can be easily fabricated using "hand lay-up" techniques used to fabricate polyester composites (see Figure 4). In this fashion, pipes, ducts, tanks, scrubbers, etc., are produced for use with process media which quickly... 

In the context of corrosion, composites refer to glass or other fiber or flake-reinforced thermosetting resins. Composite products use for their anticorrosion properties are fiberglass-reinforced pipe and storage tanks, fiber-reinforced plastic grating, handrails, I-beams, and other shapes equal to these that are made of steel. 

Another method of manufacture of solid-wall pipe is to extrude and wrap molten sheets or strips of thermoplastic around the outside surface of a tubular mandrel. Where this method is used, this pipe is manufactured to a controlled inside diameter. Continuous fiberglass-reinforced thermosetting resin pipe is generally manufactured in this manner. Some types of spiral-strip-wound composite piping are manufactured by being formed against the inside surface of a tubular fixture. 

Fiberglass reinforced plastic (FRP) is used in composite systems. It is particularly important in the process industry because of its corrosion resistance and light weight. The epoxy resin in the FRP matrix begins to melt at approximately 150°C (302°F). This may be used as a first-order failure criterion. Failure of empty 5-mm thick FRP pipes in 2-6 minutes has been reported (SINTEF,... 

Polyester-based resins are also used in bulk plastics in fiberglass reinforced fabrications such as boats, auto body repairs, and for very large structures such as industrial vessels and pipes, and ships for mine sweeping [10]. This technology uses a combination of polycondensation and vinyl-type (chain reaction) technologies to obtain the final composite product. The viscous, still fluid resin used for layup is a linear unsaturated polyester of relatively low-molecular weight. Unsaturation is introduced into the backbone of the polymer by using maleic anhydride to replace a part of the phthalic anhydride (e.g., Eq. 21.4). 

For a pipe less than 20 cm in diameter, the installed cost of fiber-reinforced pipe (FRP) is 50% greater than steel pipe, while for 20-40 cm pipe, the installed costs of FRP and steel are equal. In the case of pipe larger than 40 cm in diameter the installed cost of FRP is less than that of steel. Overall, the installed cost of an FRP pipe is about 30% higher than the installed cost of steel pipe (Ameron Fiberglass, Personal communication, Aug. 1999.). The 30% extra cost is the actual cost of corrosion, and the annual contribution to the total cost of corrosion by composites is 1,864 billion x 30%, which equals 559 million. 

Fiberglass Pipe Handbook, New York, SPI Composites Institute, 1992. 

Figure 3. Commercial applications of fiberglass reinforced polymer matrix composite structures. Manifold intake (top, left) shower and tub unit (center, left) printed wiring board (bottom, left) boat hull (top, right) pipes (center, right) recreation vehicle body (bottom, right). Reproduced with permission from PPG Industries, Incorporated, Pittsburgh, PA.

Armor Plate (Texas, US) is another pipe repair system that uses multipurpose fiberglass/epoxy wraps and different curing agents (see Fig. 18.11). The difference between Armor Plate and StrongBack composite repair systems (discussed below) is that Armor Plate uses chemicals instead of water as the catalyst agent. 

Reinforced Thermosetting Piping Fiberglass Pipe Institute/Composites Institute, a Division of the Society of the Plastics Industry, 355 Lexington Avenue, New York, NY 10017 The Materials Technology Institute of the Chemical Process Industries, Inc., 12747 Olive St. Rd., Suite 203, St. Louis, MO 63141-6269... 

Other civil engineering examples of polymers and composites are geotechnical fabric for soils, polymer natural gas pipe, fiberglass reinforcing-bar (re-bar), composite I-beams, as well as the aforementioned decking for bridges. 

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