First Tier 4 Machines Tested On Tennessee Valley Gas Line Construction

By Erin Nelsen, Online Editor | November 2011, Vol. 66 No. 11

In addition to several design and comfort upgrades, the excavators align with EPA Tier 4 standards limiting NOx and particulate emissions and requiring decreases of 90% from previous levels by 2014. Filtering and engine design strategies are in development industry-wide to determine the best ways to reach these standards. “Caterpillar’s new machines have a diesel particulate filter that takes the soot and burns it to ash when it reaches a certain point in the machine, leaving cleaner air going out into the environment,” Dearing explains.

Asked about the new excavators at the outset of the project, U.S. Pipeline’s Project Superintendent Dana Bratcher was enthusiastic. “For the pipeline business, the challenge is trying to keep up with equipment technology. These machines have far superior digging power and hydraulics. And I’m excited to see the computerized cameras they’ve got on them. When we can improve safety and performance at the same time, that’s a great thing.”
Of course, new technology isn’t always a smooth ride, and in Tennessee, those shiny yellow excavators were in for a tough maiden voyage.

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Difficult landscape, busy neighborhood

The project’s specific tasks involve 30 miles of loop work around an area about 80 miles square, taking up old natural gas lines 12 or 8 inches in diameter and replacing them with 24-inch pipe. The terrain is rolling, with steep-sloped hills and valleys dominating the view.

To Bratcher, the primary challenges are obvious: “The hills. Mountains, to me, are a mile up there. These are just short hills, but there are adverse conditions. The weather has not been very cooperative at all.” Weeks of unseasonable rain on the steep hillsides made for treacherous footing from project kickoff in May throughout the beginning of June. The project was limited to a narrow right-of-way, in part due to existing infrastructure. And the ground itself was mostly rock.

Public relations, too, are an area of interest, just as they have been in many recent pipeline projects. “Some of this area is rural, some of it is pretty populated, so it’s difficult to maneuver through these areas with our trucks. It’s congested,” says Bratcher. “From a public standpoint, they’re not used to construction in this area, so we’re impacting their lives too. It’s good for the community, good for the city, good for growth, good to stimulate the economy here, but no one likes to see change.“