Amarillo Project Attests To Renewed Interest In Swagelining

July 2011, Vol. 66 No. 7
During the Swagelining process, the PE pipe is pulled through a reduction die to temporarily reduce its diameter.

AJM Pipelines Educational Director, Todd Grafenauer commented, “The Swagelining technology is able to install a fully structural, interactive or thin walled HDPE. As the premise behind the technology is to achieve a ‘tight’ fitting HDPE, the wall thickness is selected based on the condition of the host pipe. If the host pipe has no integrity remaining, a fully structural HDPE pipe can be installed which would not rely on the host pipe for any strength or pressure stability. If the host pipe has some integrity, an interactive HDPE pipe can be installed which will rely in part on the host pipe for pressure stability, yet increase structural strength, span gaps and provide corrosion protection. If the host pipe is sound, but only the joints are leaking or a corrosion barrier is required, a thin walled HDPE pipe can be installed to prevent leaks and provide corrosion protection.”

Fresneda said, “Some of the same things that make the Grundoburst an effective static bursting machine also contribute to its effectiveness in the Swagelining technique. Quicklock bursting rods, for example, make the connection between the hydraulic pulling unit and the new product pipe. The rods are linked together not screwed together like traditional drill stems or other static systems. This speeds the installation process as well as the breakdown procedure. The rods keep constant tension on the product pipe and are quickly removed one at a time at the exit pit as Swagelining is in operation. It worked very well for this application.

“Also, there are several models available with different pulling force capabilities. For this project a 1250G was used. The unit offers over 285,000 pounds of pulling force. That was more than enough for the Amarillo project.”

On the job
The project was divided into two pulls of approximately 1,000 feet each. But before the actual Swagelining process could begin, several steps were needed to insure a smooth installation. First crews videoed the host pipe to assess the interior condition, identify bends/major obstructions, and to identify if any old connections existed on a line the city was not aware of. Next, the pipe was cleaned to remove major obstructions and the majority of tuberculation. Cleaning consisted of pulling metal scrappers through the pipe followed by a rubber pull-through. Finally a proving pig was sent through the line in order to ensure a free bore path of the host pipe.

While crews fused the sections of HDPE, the pulling unit was set in the receiving pit. Next, the HDPE string was placed on rollers and the Swagelining equipment was set in the insertion pit.

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