Abstract
Pipeline owners use the HDD (Horizontal Directional Drilling) installation method at locations where surface obstructions or access limitations preclude conventional trenched-in construction. Linear water crossings, such as creeks, rivers, and streams, are most commonly crossed using the HDD method – as this method reduces surface disruption in these environmentally sensitive areas. The HDD process involves first preparing a directional borehole (with at least 2 significant deflections or bends), into which the pipeline is physically dragged. The substantial force required to drag the pipe into the borehole makes coating damage much more likely than for trenched-in construction. As a consequence, the areas where coating damage is most probable occurs at exactly the locations of highest environmental sensitivity and consequence!
In the USA, the Pipeline Hazardous Materials Safety Administration (PHMSA) oversees the regulations governing gas and hazardous liquids pipelines. The Code of Federal Regulations (CFR) provide the most basic requirements for pipeline design, corrosion protection/prevention, and integrity management. However, these regulations do not presently address coating damage that may occur during construction.
This paper discusses the current state of pipeline regulation in the US as it pertains to coating requirements on new construction (including pending changes) as well as recent industry research and guidance around HDD coating integrity by the Pipeline Research Council International (PRCI). The objective of this paper is to educate pipeline owners, contractors, and coating applicators about the changes that have arisen in the past few years with regard to pipeline coating protection so that we can better protect the community and these very sensitive environments from pipeline leaks and ruptures.
