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Over the last nine years Fusible PVC® pipe has established a strong presence in the trenchless arena for long distance horizontal directional drilling (HDD) – particularly in the Southeastern United States. With drills routinely exceeding 3,000 feet in length, these installations often cross under rivers, lakes, wetlands, or simply heavily occupied easements. In addition to their length, these crossings often involve significant depth, moderate vertical radii, and challenging pipe layout conditions. An ideal HDD profile is shown below:
In the oil & gas industry steel pipe is king; and HDD installations of a mile or more are performed on a regular basis. In the water and wastewater market, steel pipe is typically the last choice of designers and end-users. Higher cost and corrosion concerns weigh heavily against the selection of steel pipe in water and wastewater applications when plastic pipe options are available. HDPE pipe satisfies these economic and design considerations, but is typically not used for extremely long crossings due to its lower tensile strength and tendency to creep over time (due to a time dependent modulus of elasticity).
The record of long distance Fusible PVC® pipe crossings completed since 2007 in the Southeast includes 11 HDD installations using Fusible PVC® pipe exceeding 3,000 feet in North Carolina, South Carolina, Virginia, and Maryland. Of these crossings, nine were over 4,000 feet long, two were over 5,000 feet long, and one exceeded 6,000 feet. The Archer’s Creek Crossing from Parris Island still reigns as the longest HDD installation of thermoplastic pipe, at a length of 6,400 feet.
These installations serve agencies such as Beaufort County Water & Sewer Authority and St. John’s Water Company in South Carolina, Brunswick County and Camp Lejeune in North Carolina, SMECO (Southern Maryland Electric Cooperative) in Maryland, and Suffolk in Virginia. Other HDD projects currently in design and expected to be executed in the next five years will likely eclipse the current projects in length, diameter, and number of installations.
Below is a list of, and sample photos from, a few of these HDD installations. For more information and technical assistance, please contact Underground Solutions at firstname.lastname@example.org.