November 2025 Vol. 80 No. 11
Features
Swampy installation didn't bog down Petro Plant's water supply pipeline rehab
Not even a swampy bog, buildings or deeply buried gas and water lines could stop a major Canadian oil producer from quickly rehabilitating a 4,000-foot-long deteriorated water supply line. The solution for installing the desperately needed new pipeline was to go deep using trenchless technology and a composite high-density polyethylene (HDPE) pipe.
It was the first time this particular product was used in this manner. The achievement was so distinctive that it was named Project of the Year for the Energy Piping Systems Division of the Plastics Pipe Institute Inc. (PPI), a major North American trade association representing the plastic pipe industry. The maker of the pipe, FlexSteel USA, LLC, Houston, was presented with the award during the association’s annual meeting in May 2025.
The existing NPS 14 carbon steel pipe was installed in 1988 to supply ambient temperature freshwater at 435 psi from two wells to a bitumen recovery facility. Even though leaking due to age, it could, however, still serve an important purpose.
Also in the way of a smooth installation were sections of the old line under up to 25 feet of soil, and the terrain along the right-of-way included muskeg. The swampy bog, along with the burial depth plus the need for expediency – taking it offline for a long period of time would curtail production – led to pulling 4,000 feet of FlexSteel spoolable 10-inch 1500 psi pipe through the old, buried pipeline.
This pipe-in-pipe installation minimized both the amount of excavation and disruption above ground. The new pipe was pulled through the old in just five days, and the entire 4,000-foot line was restored to production a short time later.
The FlexSteel pipe contains a corrosion-resistant inner liner and outer layer made from an advanced grade (PE4710) of HDPE with a helically wrapped steel reinforcement in the middle. Because FlexSteel is steel-reinforced, flexible and strong enough to transverse the steep bends of the host pipe and can be pulled in long sections, only five strategically placed bell holes were required. The pipe does not rely on the structural integrity of the host pipe and, according to FlexSteel, provides a defined 20-plus year design life due to its corrosion-resistant properties.
Delivered on reels holding 577 feet helped the pipe-in-pipe rehabilitation to be accomplished in five days. For the installation, the crew ran a gauging assembly through the old carrier pipeline to ensure it was clear of obstructions. Then, a pig was connected to a wireline unit and inserted into the carrier pipe and propelled to the entry side of the carrier pipe using compressed air. A hydraulic wireline unit pulled the flexible steel pipe through the carrier pipe. Tension in the line was monitored to prevent damage to the pipe.
“This project was exceptional in a number of ways,” said Randy Knapp, Ph.D, engineering director of PPI’s Energy Piping Systems Division. “In fewer than three weeks, starting with the initial pre-construction survey, the pipeline was in service again. Because the pipe-in-pipe or slip-lining installation method is so efficient, there was minimal above-ground disruption.
“Furthermore, the need to excavate pipe buried 25 feet below the surface or to excavate muskeg areas was avoided – an important, favorable aspect of using any trenchless installation method. Digging in that environment would also present a safety concern for the crew.”
The FlexSteel pipe is designed and qualified in accordance with API SPEC 17J and API Spec 15S to provide years of failure-free performance. Delivered on spooled reels, which is not possible with steel pipe, it ultimately saved transportation costs and further reduced the impact on the land. The long, continuous lengths that required minimal connections also greatly increased the integrity of the pipeline, provided cost savings and made it possible for it to be installed in a narrow trench and much faster than steel pipe – about one-third the time.
According to PPI, the spoolable composite pipe structure using PE4710 HDPE allows for the maximization of pipe performance in a system, bringing an excellent level of slow crack growth resistance and enabling a piping system to be operated at high pressure without sacrificing safety or service life.
FOR MORE INFORMATION: PPI, plasticpipe.org/EnergyPipingSystems
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