External Strengthening of In-Service Pipe
Fibrwrap Construction recently aided a large industrial facility in the United States by renewing a 300-ft. cast iron pipeline constructed in the 1920s. The pipe, with pipe segments ranging from 24-inches to 72-inches in diameter, had experienced significant degradation over time and was in need of repair.
The pipe had been structurally wrapped in the mid-1960s with a polyester resin-saturated glass fiber system designed to withstand up to 100 psi. An evaluation of thisexisting glass fiber wrap installed in the 1960s confirmed that it was near the end of its reliable service life. Due to the critical nature of the pipeline, a proactive strengthening of the pipeline was selected by the owner to avoid structural concerns.
Continuous use of the cooling water pipeline is necessary for plant operations at all times. Any outage in service for the pipe would require a plant wide shutdown -- costing the facility over $1 million per day. Therefore, plant operators had to choose a solution requiring zero downtime to install. The owner chose to rehabilitate the pipeline using the externally-applied Tyfo® Fibrwrap® composite system manufactured by Fyfe Company, LLC.
The selected rehabilitation system consisted of a combination of Tyfo® WEB bi-directional glass fiber-reinforced polymer (FRP) and Tyfo® SCH uni-directional carbon FRP. The product was specially designed to provide a structural solution without relying on the cast iron host pipe or the existing glass fiber wrap. Installed without taking the header out of service, the layer of Tyfo® WEB conformed to the external geometry of the pipe and provided load continuity in the transverse direction of the hoop layers of the Tyfo® SCH, which resisted the internal design pressures.
During installation, the outer surface of the existing glass fiber wrap was prepared in order to provide adequate adhesion for the Tyfo® Fibrwrap® system. After application, the completed product was then finished with a UV-resistant coat of Tyfo® U coating. Fibrwrap® Construction performed the installation safely and successfully within the schedule requirements provided by the owner.