It’s a challenge that natural gas utilities across the country are facing: Retrofitting or replacing transmission and distribution pipelines built decades ago to ensure a utility can continue delivering safe, reliable and cost-effective natural gas to its customers.
In Chicago, the Calumet #3 transmission pipeline provides roughly one-third of the natural gas supply to customers throughout the city—about 300,000 households. For one part of it, there was a simple pipeline issue that engineers and workers laying pipe in 1959 couldn’t have foreseen: The change in diameter (reduced from 36 to 30 inches) and two 150-foot vertical risers into a tunnel, making it impossible to perform modern inline pigging.
As part of a large retrofitting project for Calumet #3, engineers at Peoples Gas in Chicago planned to replace the 60-year-old river crossing. But here’s where simple gets more complex: The particular piece of transmission pipeline was 1,500 feet long—the length of nearly five football fields—and it was located roughly 30 feet under the Calumet River on Chicago’s southeast side.
A project like the Calumet River crossing might come up every five to 10 years, said Joe Tassone, manager-construction, south district and high pressure, for Peoples Gas. But the fact that it was completed successfully—on time, safely and employing technology never before used to lay 1,500 feet of pipe—offers valuable lessons for any utility.
Project Director and Manager Jon Czarnecki recalls hearing about the Calumet River crossing soon after he joined Peoples Gas in 2015. “My mind went right away to directional drilling the river,” he said. “They said, ‘We can’t.’ And I said, ‘OK, why not?’”
It came down to geology. “Really, the first thing you do for any type of trenchless project under a river or significant geologic structure like this is to do some soil borings,” said Kyle Frayn, manager of transmission design for Peoples Gas. “What became quickly apparent was that we had a relatively narrow band between the bottom of the river and where the bedrock started.”
With traditional horizontal directional drilling, there is significant hydraulic pressure that can create a risk of “frac-out,” or the release of drilling fluid into the surface environment. “You will more than likely have a poor relationship with your local DOT or even the EPA if you generate an inadvertent return in a navigable body of water,” said Tassone. “The reputational and PR aspects were a concern for us as well.”
A secondary challenge was that engineers and workers had only a small physical footprint to work with for staging and the actual pipe installation, even with careful mapping and obtaining the proper easements and land rights.
Horizontal directional drilling and jack and bore are two common installation methods that utilities in the United States are most accustomed to, but neither would work for this particular river crossing. A third—done in Europe for two decades and the United States for less than a decade (seven years at the time of the installation), with roughly 150 projects successfully completed worldwide—is direct pipe.
The trenchless technology involves far less hydraulic pressure, using in this case a 36-inch bore hole that would be continually supported by sacrificial pipe, using a microtunneling method that would push pipe through as it passed under the riverbed. It also requires a smaller physical space to operate, since the overall length of the crossing would be shorter and all construction operations could be performed on one side of the river.
“Utilities tend to be cautious about adopting new pipeline installation technologies,” said Tassone. “We’re seen as very stable companies, so when we start to look at new technologies that aren’t yet mature, there’s an element of risk.”
So it was with some skepticism that leaders at Peoples Gas began to talk with Michels Corporation, one of only a few contractors in the United States offering the solution. Michels has successfully completed past Peoples Gas projects using other installation methods and shared both references and information on previous projects using direct pipe.
“As Michels Corp. gave us more information about direct pipe, we started to get a little more comfortable,” said Czarnecki, who says Peoples Gas asked many questions and also asked for contingencies for multiple scenarios. “It felt like a partnership.”
With the complexity of the Calumet River crossing, once an initial strategy was in place, the team at Peoples Gas and Michels met three times a week for three to four months prior to construction start.
Determining the right installation method was one large hurdle. The next would be the land rights, easements and permits. “The real estate portion of this work took four or five times longer than anyone expected it would,” said Frayn.
One side of the river was home to a Ford Motor Company employee parking lot, and the company was “more worried about not having their operations impacted than having us pay for an easement,” he said. The other side was railroad property, which hadn’t been sold in 100 years, causing headaches in tracking down the proper ownership, as the list of owners swelled from two to five.
When it came to permitting, like most urban areas, the city of Chicago has a comprehensive process. The large diameter of the installed steel pipe (36 inches) and the direct pipe technology added additional levels of scrutiny and review, said Frayn. “We spent some time with the city, talking about their concerns … and helping them to understand the newer technology,” he said.
Peoples Gas’ Calumet project would join roughly two dozen direct pipe projects completed in the United States—but would be the only one completed by a local distribution company. At a diameter of 36 inches, the Calumet River crossing would also be the longest installation ever completed, at 1,500 feet.
Although there were contingencies in place—including the fact that the existing pipeline would continue flowing gas—the project had a hard stop of Dec. 1 to ensure no interruption to gas delivery as temperatures plummeted and winter demand started to rise.
Originally, preparations were to begin on-site on July 1, but some technical delays and the ongoing easement and permitting issues pushed that back. With those challenges, leaders decided to fall back to a contingency plan: Once work started, it would continue 24/7, employing two 12-hour shifts each day.
On Aug. 10, Peoples Gas and the Michels team mobilized to the Calumet River to begin preparing for the installation, which included two weeks alone to clear out foliage and set up the staging area. Sacrificial and production pipe was then delivered and welded together, followed by the direct pipe equipment, which was installed on-site.
On Sept. 21, the physical installation began. The microtunneling machine dug at a rate of about 10 feet per hour in softer dirt, and 1 foot an hour when it struck rockier soil or clay. After nine days, the machine had tunneled 420 feet, nearly a third of the way, when there was a failure in the pump mechanism. After aboveground troubleshooting and underground confined-space entry both failed, the team made the tough decision to pull out the equipment and the sacrificial pipe to make the repair.
Four days after they started mining again, after the machine had tunneled 976 feet, there was another issue—a communications problem with the equipment. Again, above- and below-ground troubleshooting failed, and the pipe had to be extracted.
“We had some tough and challenging meetings between us and Michels,” said Tassone. Those meetings even included bringing in specialists from the German company that manufactures the direct pipe equipment. “But we were all very committed to getting through the challenges … and we kept our composure as we addressed the issues.”
It helped that Michels explained that extractions like these weren’t uncommon and that the company offered up some contingencies, including bringing in a larger tunneling machine. Ultimately, the team jointly determined to continue with the original plan.
On Oct. 23, just a little over a month after tunneling began, the bore head emerged on the other side of the river. “I was ecstatic,” said Czarnecki. “But I was thinking, ‘OK, that’s out; now we still need to push the rest of the pipe through, then there are all these other events to take care of … . So, we celebrated for five minutes, then got back to work.”
After the sacrificial pipe was pushed out and the production pipe installed, the team placed the remaining pipe, including dewatering systems, on either side of the river, then performed a caliper pig run and a hydrostatic test of the new pipeline. Over two days in November, just before Thanksgiving, the new pipeline was tied in, then brought up to operating pressure on Nov. 24, six days before the deadline.
No matter how big or how small, the success of any project often comes down to communication and planning, and it was the same for the Calumet River crossing, said project organizers.
Peoples Gas began the planning process in January. “I would be very wary of starting some type of trenchless crossing without having a backup plan in place, or much less than a year or so of timeline until you needed the asset in service,” said Frayn.
Multiple contingencies were established through intense conversations with the contractor. “You’ve got to be comfortable with their expectations and your expectations,” said Czarnecki. “We talked with Michels about what if this goes wrong and other projects are delayed on your schedule. Will you finish this [project] for us, or is there money to be made somewhere else? These are uncomfortable, but critical, conversations that you need to have so you don’t run into any surprises when you’re under pressure and things get tough.”
Peoples Gas also found that land rights and easements can be the wild card, said Frayn. “You can only control that to a certain extent,” he said.
The Calumet River project served to demonstrate that it’s important to have land rights defined at least six months prior to a project’s start date—or three months at the latest. For example, railroad properties alone may require two months or more to complete a proper title search.
From a safety perspective, Peoples Gas and Michels completed the work with no Occupational Safety and Health Administration injuries or lost-time incidents, no defects in the welds or coating, and with the pipeline operating at the proper pressure. During the work itself, inspectors watched closely for worker fatigue related to the pressure of the 24/7 work but found that the strategy of using two 12-hour shifts worked successfully.
A “lessons learned” meeting following the project’s end also identified the need for additional confined-space entry training and a closer examination of project execution to determine more instances where work could be completed concurrently to tighten schedules.
While the direct pipe method isn’t one that could or should be used for every pipeline replacement project, it is a viable option for any project where pipe needs to travel under an obstacle.
“Any new installation method like this carries some element of risk,” said Tassone. “We took a leap of faith, and it paid off for us. But there were a number of reasons: a good partnership with our contractor, doing our homework to be educated as best we could … and the work was done in a way that made the most sense for us, considering all of our viable options.”
On Pipeline Replacement
Elements of a successful pipeline project include:
Source: Peoples Gas