PipeWrap Underwater Structural Strenthening

Antioch, TN
Pipe Wrap®: Underwater Structural Strenthening

Challenge

In 2015, a natural gas pipeline in Tennessee needed to be restored to its full structural integrity in order to prevent potential explosions and other environmental hazards. While many pipeline repair projects can be relatively simple for asset owners and contractors, this job presented a number of unique challenges. 

Not only was the pipe buried beneath heavy rock that may have caused the initial damage, but it was also located more than 40 feet underwater, making repair access difficult and limiting repair options.

As part of standard maintenance, an ultrasonic, smart pigging system was inserted in the 30-inch diameter pipe to evaluate any deficiencies along its interior and exterior walls. Log data accumulated from the system revealed anomalies along a seven linear foot stretch of pipe. The surrounding rock was immediately removed, and the asset owner began exploring options for pipe rehabilitation.

The asset owner evaluated pipe welding and various composite rehabilitation methods to repair the damaged section of pipe. Pipe welding is a time- and labor-intensive option that would have involved shutting in the line, terminating production and cutting out the old pipe before beginning the hot work. In addition to the potential revenue loss from the flow stoppage, hot work near a natural gas pipeline presented a number of safety hazards for the contracting team.

Composite repair systems are categorized by material properties and installation methods. In one method, using wet lay-up techniques, a resin is field-applied to the wrap before sending it underwater, complicating the process for pipe adhesion. Alternatively, SplashGard II A+ Wrap from Milliken Infrastructure Solutions’ (MIS) Pipe Wrap brand – a preimpregnated composite repair system – uses a water-activated urethane resin that cures with epoxy applied to the pipe prior to the wrap.