Composite piping applications

The probabilistic analysis presented in this chapter is not restricted to a specific fabrication approach but rather presents results as a function of the fiber volume fraction and can be applied to a wide range of pipe rehabilitation methods. The time-dependent failure probability analysis is illustrated for specific fiber volume fractions and can be repeated for any fiber volume fraction depending on the manufacturing process of interest. Typical fiber volume fractions of 30% and 40% are selected conservatively for example probability analysis conducted in the chapter. Recent efforts to measure fiber volume fractions used in composite pipe applications report fiber volume fraction values ranging from 47.6% to 54% for filament-wound composite pipes (Abdalla et al., 2008), and Chin and Lee (2005) measured volume fractions of 47% for unidirectional laminates manufactured via resin transfer molding in a trenchless rehabilitation scheme. 

The newer open-cell foams, based on polyimides (qv), polybenzimidazoles, polypyrones, polyureas, polyphenylquinoxalines, and phenolic resins (qv), produce less smoke, are more fire resistant and can be used at higher temperatures. These materials are more expensive and used only for special applications including aircraft and marine vessels. Rigid poly (vinyl chloride) (PVC) foams are available in small quantities mainly for use in composite panels and piping applications (see Flame retardants Hrat-rrststantpot.ymf.rs). 

Polyester PC is used in various procast and cast-in-place applications in construction works, public and commercial buildings, for the manufacture of sanitary engineering, cladding of composite pipes in bathrooms and toilets, stairs, and chemical-resistant floors [2,6,7],... 

Glass fiber-reinforced polymer (GRP) pipe is used for the transport of water and wastewater in pressure and non-pressure systems. This composite is composed of glass fiber and PP, PE, or PVC resins. These pipes are lightweight, corrosion resistant, and straightforward to install and have a long and effective service life and low maintenance costs. These features make GFR POCs, a strong candidate for piping applications in environments with acidic soil [51]. 

While epoxy resins are known for excellent chemical resistance properties, the development and commercialization of epoxy vinyl ester resins in the 1970s by Shell and Dow offered enhanced resistance properties for hard-to-hold, corrosive chemicals such as acids, bases, and organic solvents. In conjimction with the development of the structural composites industry, epoxy vinyl ester resin composites found applications in demanding environments snch as tanks, pipes and ancillary equipment for petrochemical plants and oil refineries, automotive valve covers, and oil pans. More recently, epoxy and vinyl esters are used in the construction of windmill blades for wind energy farms. Increasing requirements in the composite industries for aerospace and defense applications in the 1980s led to the development of new, high performance multifunctional epoxy resins based on complex amine and phenolic structures. Examples of those products are the trisphenol epoxy novolacs developed by Dow Chemical and now marketed by Huntsman (formerly Ciba). 

There are also a number of patents on even more challenging applications for pipes [12]. For example, ABB claimed a PEEK pipe wrapped in continuous carbon fibre PEEK composite for use as an oilfield riser. Such risers could be several kilometres long and their near neutral buoyancy and excellent environmental resistance would allow recovery of oil from the deep oceans. The specific mechanical properties of composite pipes mean that they may also find uses as drill pipes. 

For buried nonpressure apphcations, a composite pipe (ASTM D 2680) is produced that consists of two concentric tubes that are integrally braced with a truss webbing. The resultant openings between the concentric tubes are filled with a hghtweight concrete. This construction increases both the ring and the beam stiffness. Composite pipe is used only for nonpressure buried applications such as sewerage and drainage. 

Composite glass-reinforced polyethylene (PE-GF) piping products, where short glass fibers are mixed directly into the polymer matrix in polymer extrudate, are a recent development and have been introduced for large-diameter piping applications, up to 120-in. diameters and even larger, in Europe. 

Composite spiral-wound steel-reinforced drainage pipes have also been developed in Japan and Australia and recently introduced into North America. These are used for larger-diameter piping products for storm drainage and sanitary sewer piping applications. 

Aluminium/plastic composite pipes for heating and sanitary applications are manufactured in five layers two layers of silane-crosslinked HOPE with an aluminium core and two adhesive layers. The aluminium layer provides an oxygen barrier. 

Applications. Epoxy resias constitute over 90% of the matrix resia material used ia advanced composites. In addition, epoxy resias are used ia all the various fabrication processes that convert resias and reinforcements iato composite articles. Liquid resias ia combiaation, mainly, with amines and anhydride are used for filament winding, resia transfer mol ding, and pultmsion. Parts for aircraft, rocket cases, pipes, rods, tennis rackets, ski poles, golf club shafts, and fishing poles are made by one of these processes with an epoxy resia system. 

---