This article was originally published as "CCFRPM Pipe Tests Time" in the September 2019 print edition of iWWD.
One of Hobas Pipe’s first fiberglass pipes manufactured in its Houston, Texas, plant in 1987 still is in use and still exceeds ASTM standards. This means it has lasted more than twice the useful lifetime for other common pipe materials under the same environmental conditions.
In June 1987, Hobas announced the grand opening of its new fiberglass pipe facility in Houston, Texas. At the same time, a large provider servicing a west Texas oil field was in need of new service lines, and the corrosion resistance of the fiberglass pipe was a perfect match for the environment.
West Texas Water Supply System (WTWSS), a privately owned commercial water delivery system serving the oil industry, was expanding its distribution lines. Two separate 18-in. diameter lines were included in the project to deliver brackish water originating from the Capitan Reef Complex Aquifer to oil fields in the Midland and Odessa area. The WTWSS lines have changed ownership over the years, having been acquired by Centurion Pipeline L.P., which in turn was acquired by Lotus Midstream LLC.
CCFRPM Pipe & Brackish Water
The groundwater pumped from this aquifer, located in southeast New Mexico and far West Texas, is transferred to regional oil fields for use in secondary recovery processes. This brackish water has a temperature between 90 to 95ºF and is contaminated with hydrogen sulfide and other minerals. Due to the water’s high salinity characteristics, pipes made of other commonly used materials experience a shorter lifespan under these same conditions.
Engineers designing this project chose centrifugally cast fiberglass reinforced polymer mortar (CCFRPM) pipe because of its inherent corrosion resistance. WTWSS management expected a 50-year or longer service life for the fiberglass pipes in this environment. Both pipelines used minimum pipe classes PN 150 (maximum 150 psi operating pressure), SN 36 (minimum 36 psi pipe stiffness).
For installation, the CCFRPM was delivered in 20-ft sections and field-assembled with standard FWC couplings. The first phase was a 21,000-ft extension line to supply a Chevron field near Goldsmith, Texas. Field-tested to 185 psi, the line was put into service delivering 35,000 barrels per day. The second phase of the project included a 124,000-ft extension to supply a Texaco field on Mabee Ranch north of Midland, Texas. Each of the lines was capable of delivering 120,000 barrels per day at capacity. Under normal operation, these lines operated between 75 and 100 psi of pressure.
For more than 20 years, these two lines were out of sight and out of mind. But then an adjacent pipeline consisting of another material ruptured and damaged several segments of one of the existing lines. Within one week, the Hobas Pipe plant in Houston manufactured and shipped 80 ft of new 18-in. diameter CCFRPM pipe to the west Texas repair site.
It is rare that segments of historical lines are available for testing before they reach their full life expectancy, as most remain in use for their lifetime. In this instance, Hobas was fortunate enough to receive some of the 21.5-year-old pipe at its plant, where the company determined it was one of the first fiberglass pipes manufactured in the USA in November 1987. The damaged sample was inspected by an outside testing facility that oversaw the testing of returned pipes. The third party evaluated the mechanical properties in accordance with the ASTM standards for the product. Physical testing of specimens included axial tensile strength and strain, hoop tensile strength, hoop flexural strength and strain, and axial compressive strength. In all cases, the results of these tests showed the CCFRPM had exceeded the original ASTM requirements. Quickly repaired, this line is once again out of sight and out of mind.
Pumped Storage Facility
Hydroelectric penstocks utilize water and elevation (water head) to generate electricity. It is one of the cleanest, most reliable and cost-effective sources of energy. Penstocks have been in operation in the U.S. for years; however, many installed in the last century are reaching the end of their useful life. To preserve this environmentally friendly energy generation alternative, rehabilitation projects are underway across the U.S.
One such penstock located in Connecticut is utilized to store energy. An 8-sq-mi storage area is filled by pumping water from the river during periods when electricity is least expensive. When electricity demand reaches a peak, water is released through the same penstock, and the motors driving the pumps reverse to become generators that produce electricity.
The penstock transports water between Candlewood Lake (upper reservoir) and the plant’s surge tank above the Housatonic River (lower reservoir) by means of the Rocky River plant. Candlewood Lake was named for nearby Candlewood Mountain and is the largest manmade lake in the state.
Like many older penstocks, Rocky River was a wood stave pipeline. The original penstock, which operated from 1928 to 1965, was made of Douglas fir that was held in place by iron rings. In 1965, the penstock was replaced by another made of the same materials. Again, this material outlived its useful life and the owner and engineers looked for another solution.
This time, the solution was CCFRPM pipe. Hobas supplied 950 ln ft of 120-in.-diameter CCFRPM pipe that included three miter joints to navigate directional changes. The pipe was manufactured with a stiffness class of 36 psi and pressure class of 26 psi. The pipe provided a structurally sound replacement, eliminated the leaking joints that had been problematic over the years, and will require little maintenance.
“Rocky River, owned by First Light Power (FLP), is located in Connecticut. The 15-ft-diameter wood stave penstock’s leakage resulted in safety concerns, and costly maintenance had become time consuming and prohibitive. The final configuration consisted of a 10-ft-diameter [fiberglass reinforced polymer] FRP pipe with an estimated service life at least equal to steel but with less maintenance,” said Jillian Davis, P.E., Kleinschmidt Associates.