Development of Shale Play Slows, but Other Pipeline Work Continues

by Luke Jones  on Monday, May. 27, 2013 12:00 am  

Thirteen states have eliminated cast iron pipes entirely.

PHMSA reports that Arkansas has only 145 miles of iron main lines. That represents 1 percent of the state’s total main line mileage.

None of the state’s pipes transporting gas between main lines to customers are iron.

By comparison, New Jersey has the most iron pipe, with 5,044 miles of iron main lines, representing 15 percent of the state’s main mileage.

Washington, D.C., has the highest percentage of iron pipes, with 35 percent, or 419 miles, of its main lines.

Steel pipes are built in rolling mills. Sections tend to be from 40 to 80 feet in length.

The geographic conditions of the area determine the physical aspects of the pipe; a 1971 federal standard requires them to be coated in coal, tar, asphalt or wax as protection against the elements.

Construction standards are imposed by committees of industry groups like API or the American Society of Mechanical Engineers, as well as various government entities. API, for example, sets standards for line pipes and welding.

After the site is prepared, the pipe sections are laid out along the right-of-way in a process called “stringing.”

Following this, holes are dug under the right-of-way into which the pipes are laid.

Special bending machines alter the shape of certain pipe sections to accommodate topography changes.

Pipe sections are then welded together. The weld of the pipe is actually stronger than the pipe itself. Secondary coating is applied to the ends of the pipe sections. Joints are coated with bonds like epoxy or polyethylene heat-shrink sleeves.



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