HORIZONTAL DIRECTIONAL DRILLING GUIDELINES FOR INSTALLING POLYETHYLENE GAS DISTRIBUTION PIPES. TOPICAL REPORT, NOVEMBER 1994-MARCH 1997

Directional drilling is a no-dig trenchless technology that is being used increasingly by gas utilities and their contractors to install polyethylene (PE) gas pipes. The process typically involves two major steps: 1) drilling a pilot hole from the entrance pit to the exit pit that defines the installation profile, and 2) pulling in the pipeline from the exit pit to the entrance pit as the bore is enlarged through a back-reaming process. This document was developed from interviews with gas utilities that use in-house drilling crews, pipeline contractors, and construction companies that perform drilling operations. Analyses were also performed to develop guidelines on issues such as maximum pull length for a given size pipe. The guidelines represent recommended best practices, which, if followed, should benefit gas utilities in at least three ways by enabling them to develop: 1) company-specific internal standards for in-house drilling crews, 2) specifications for contracting for services; and 3) training and quality control procedures for in-house drilling crews and outside contractors.