HDPE Conduits

What is HDPE?

High-density polyethylene (HDPE) conduit is the preferred material to house and protect electrical power and telecommunications cables within. It offers unmatched corrosion and chemical resistance, is flexible, durable and available in long reel lengths to reduce joints and installation time. HDPE conduit is available in a variety of sizes, colors, dimensions and lengths.

History of HDPE Conduit

The early driver behind the use of conduit produced from high-density polyethylene (HDPE) was for deploying and protecting fiber optic (FO) cables placed underground for the telecommunications industry. Tremendous growth occurred for the installation of fiber optic cables during the early to mid-1980s for linking major metropolitan areas. This era saw massive projects where FO cables were being deployed in both aerial and underground installations. These fiber optic cables were typically made and installed in very long lengths up to 30,000 feet (9,145 m), with the goal of using as few splice locations as possible to minimize signal attenuation or decibel (dB) losses in a complete system.

Fiber Optic Cable & HDPE

Fiber optic cable and the equipment used to send and receive light waves were in the early stages of becoming the technology of choice for streaming huge amounts of voice, video and data over fibers not much thicker than a human hair. However, FO cable needed more protection and different handling procedures as compared to traditional jacketed metallic cables. For buried installations, there was an immediate need for a conduit system that would offer improved installation efficiencies and cable protection.

Metro Areas

In metropolitan areas, the smaller diameter FO cables were replacing very large diameter copper cables that filled banks of conduits made up of individual lengths of 3 ½ inch to 6 inch diameter conduits. As these large copper cables were being removed, telephone companies began installing small conduits ranging from 1 to 1 ¼ inch, using HDPE water pipe as the conduit. Multiple 1 or 1 ¼ inch HDPE water pipes, commonly termed “innerducts”, would be pulled into the vacated larger diameter conduit left behind after the copper cables had been removed.

The newly installed HDPE innerducts created multiple pathways that could be used for initial and future fiber optic cable placement, or to use as spares for rapid FO cable deployment in case the initial FO cable got damaged. Multiple 1 inch through 4 inch HDPE innerducts were also being installed in the more rural parts of the network. Much of this work was completed by using new trenchless methods like rail plowing and horizontal directional drilling (HDD), also known as directional boring.

This new technique was employed to install pipes, conduits or cables below ground using a surface-mounted drill rig that launches and places a drill string at a shallow angle to the surface, and has tracking and steering capabilities. These procedures are intended to minimize above and below ground surface damage, restoration requirements, and disruption to traffic, with little or no interruption of existing services.

HDPE Conduits