Structural Pipeline Rehabilitation by Externally Wrapping with FRP

Fiber reinforced polymers (FRP) have been gaining momentum in the last decade for structural pipeline rehabilitation in addition to other infrastructure. The advantages these systems provide include having the highest strength to weight ratio in the industry, corrosion resistance, and ability to install with minimal disruption, footprint, equipment, and greenhouse gas emissions. Another advantage FRP systems provide is the ability to install them externally on a pipe without the need for stopping the flow of disrupting service. Use of externally wrapping has been more common in the energy industry as well as in other manufacturing facilities where pressures and safety factors can be quite high. As such, there is more experience in the field of mechanical engineering than civil, and ASME’s PCC2—Repair of Pressure Equipment and Piping, Part 4 provides detailed guidance for designing carbon fiber reinforced polymer (CFRP) wrap on energy and other facility piping. This paper will discuss the design methods for FRP linings with respect to differences in external and internal applications. The internal pressure design equations included in PCC2/Part 4 and AWWA C305 will be reviewed, and differences will be outlined. Then case studies on pipeline rehabilitation by externally wrapping of pipes with FRP in the water and wastewater facilities will be presented. The design methods used in those case studies will be elaborated.