Gas pipeline rehab projects are challenging enough when planned for and the challenges increase when the project is needed due to an emergency. It’s in these emergency moments that trenchless experts from the contracting, engineering and manufacturing sectors come together to break open their collective toolboxes and let their ingenuity shine.
Such was the case in early 2020 in South Orange, New Jersey, when it was discovered that there was a leak in the Public Service Electric and Gas Co. (PSE&G) line running in an easement adjacent to the ever-busy South Orange Avenue and the East Branch of the Rahway River.
During the winter of 2019-2020, PSE&G was notified of a 15-psig leak on a 36×30-in. steel reducer and made a temporary repair with a concrete cap and a 2-in. vent line to vent the leaking gas as a safety measure. The reducer connected 10 lf of 30-in. cast iron main and a gate valve to a short 165-lf segment of 36-in. steel pipe. Buried more than 10 ft deep, the main was surrounded by – among other things – a critical large diameter water main, a 6-ft-wide telephone switching bank going to 8 ft deep and other essential underground utilities.
Why ‘The Mess?’
Adding to the challenge, in this short 175-lf section of the pipe were six complex compound bends, an opening for an inaccessible, active 20-in. lateral, and a legacy drip stack assembly made of steel located near monitoring well shafts around a decommissioned underground gasoline storage tank. On the east side of the project, the pipe plunged down from 5 ft to 15.5 ft to cross under the Rahway River, then rose sharply to a 10-ft depth on the west side of the river to connect with the inaccessible 30-in. gate valve, leaking reducer and a short run of 30-in. cast iron pipe stretching westward. The project team affectionately dubbed this section “The Mess” because it resembled a “tangled knotted ball of yarn.”
It is because of these technical complexities and the ingenuity and technical advancements necessary to complete this job that it was chosen as the 2021 Trenchless Technology Project of the Year for Rehabilitation.
“At only a short 175 lf length, with six bends, compounded and complicated by the challenging three-dimensional stack drip geometry fabricated of a tee with one leg looking down, reducer and gate valve, ‘The Mess’ was by far the most complex lining configuration attempted for CIPL,” says George Ragula, CEO of RagulaTech and PSE&G’s engineer for the project. “A 36-in. liner had to invert through a 36×30-in. reducer, a short section of 30-in. pipe, a 30-in. gate valve, a second 36×30 in. reducer, and then navigate six compound bends, also traveling past the lateral and stack drip geometry to invert through the entire 165-ft length of 36-in. steel pipe.”
The utility, with Ragula leading the design, looked at its toolbox to see what could be done, knowing that a trenchless solution was necessary given the congested and difficult to reach segment.
“This is a critical supply source that extends to the western portion of our territory. We knew there were several active leaks, and we also knew that there were many mechanical joints that were not sealed,” says Ragula. “Based on that, there wasn’t any thought about holding off on it. We were up against a short outage because of the criticality of the feed, so it unfolded quickly in May when we started talking about it.”
Trenchless Team Assemble
Ragula knew who he had to call to make this project go forward. Bringing the project to fruition was a team effort that included Progressive Pipeline Management (PPM), A&W Maintenance, Camden Group, ULC Robotics and Miller Pipeline.
“As the engineer of the project and my active involvement with NASTT, I always tracked trenchless industry innovations and advancements to stay abreast of the state-of-the-art of technology to keep such solutions in my back pocket as the opportunities arose,” he says. “When this project surfaced, I knew there was only one way to successfully complete it and immediately started planning activities with the various contractor/supplier teams to confirm constructability of something that had never been accomplished before.”
Planning began in May 2020. including PPM procurment, manufacturing and shop testing a trio of items that would prove to be industry-firsts on a CIPL project.
“We’ve been working with PSE&G since our company’s inception 20 years ago and we work well with them, and George [Ragula] specifically, on the designs,” says David Wickersham, president and CEO of PPM. “Once we received the plans from George, we sat down and laid things out to make sure we had the tools in our tool bag to make sure the lining was successful. That includes working with George, Avanti grouts and Warren Environmental to help us with a design to make sure the liner went through.”
First, the team had to procure and test a second 36×30 reducer to be used ahead of the 30-in. gate valve as removing the gate valve and the leaking 36×30 reducer was impossible. The team also needed to construct a 10-ft section of 36-in. guide pipe to ensure the 36-in. liner was aligned properly going through the two reducers and the gate valve. The team then tested the two components together to confirm that there would be minimal wrinkling and the liner would be structurally sound.
They also built and tested a temporary 20-in. restraint plug to block off the 20-in. lateral to provide a bearing surface as the liner passed the lateral so it would not rupture at the opening. Prior to lining, Miller Pipeline used its Weko-Seal product to seal the joints in the lateral.
With these custom-fabricated items tested and the team confident in its plan, PPM mobilized to the site on Aug. 17, 2020. Before it could clean and inspect the main, a critical step was needed to ensure water would not infiltrate the de-pressurized main since it is below the water table.
Ragula went into his trenchless files and pulled out the one marked curtain grouting. Used for the first time on its record-setting 42-in. CIPL project under the Garden State Parkway in 2019, he knew this method would successfully stop inflow and infiltration into the pipe once it was depressurized. This work was completed by Camden Group using Avanti grouts. It was completed ahead of PPM’s sandblasting the main and inspecting it in preparation of the lining.
Following the cleaning, one more key bit of preparation was required to ensure the liner would travel through The Mess just as smoothly as if it were a straight section of pipe. Ragula, working with Warren Environmental and its installer A&W Maintenance, discussed the use of high-strength epoxy to complete a trio of industry-firsts:
Fabricate a 90-degree bend at a 36×36 Tee of a stack drip fitting. In normal circumstances this legacy fitting would be removed but given the monitoring wells, that was impossible. Creating the 90-degree bend would create a suitable curve for the liner to travel along.
Using the epoxy to create a smooth epoxy bridge at a 30-in. valve gate well to provide a bearing surface for the inversion.
Coating the interior of the leaking 36×30 reducer ahead of lining to reinforce and add strength to the leaking fitting.
“Just as important to PPM’s relining work is the curtain grouting completed by Camden Group using Avanti grouts and the epoxy work done by A&W Maintenance using Warren Environmental’s epoxies,” says Ragula, heaping praise on the project team. “PPM would have not been able to do anything had the curtain grouting and epoxy work not been successful. Those were two critical milestones that needed to be successfully completed for PPM to move on to their portion of the work.”
Wickersham adds that he knew his team could get the job done as they’ve lined through bends and reducers in the past. It was the grouting and epoxy work that were imperative to their success.
“Operationally, everything went true to form and as planned. There were no deviations in the field or surprises that sprouted up. We executed the plan as designed in the office,” says Wickersham. “It’s nice to work with George and PSE&G, as well. It’s been a long, positive working relationship since I started PPM 20 years ago. They are strong proponents of lining and know where to apply the technology for maximum savings.”
On Aug. 31, with the grouting, cleaning, inspection and epoxy work complete, PPM was ready for the inversion. All told, the inversion took less than two hours. Where the 36-in liner wrinkled in the 30-in sections, the voids behind the wrinkles were filled with resins to ensure gas would not escape should the liner have any leaks.
Ragula notes that while, the team was done with The Mess on Aug. 31, PSE&G and PPM took the opportunity to reline an 825-lf section of the 30-in. cast iron pipe on the west side of the river and 875 lf of 36-in. cast iron on the east side of the river. The entire segment was pressure tested, the liner was cut away at the 20-in. lateral and the cap was removed, and the segment was gassed in Sept. 29.
“Comparing this to our record-breaking 42-in. project from 2019, I thought that was the most difficult because it was massive, but really the 42 was a cakewalk compared to this,” says Ragula. “There was a lot of innovation and advancements that needed to be deployed to do this correctly and properly so that we would be successful.”
Project Owner: Public Service Electric & Gas (PSE&G)
Engineer: George Ragula, PSE&G
Contractor: Progressive Pipeline Management; Subcontractors: Camden Group, A&W Maintenance, Miller Pipeline, ULC Robotics
Suppliers/Manufacturers: Avanti International, Warren Environmental, Karl Weiss Gmbh, Weko-Seal
Value of Trenchless Project (US$): $3.5 million