Pipeline process services

HDD

Horizontal Directional Drilling or HDD, is a steerable trenchless method of installing underground pipe, conduit, or cable in a shallow arc along a prescribed bore path by using a surface-launched drilling rig, with minimal impact on the surrounding area.

Directional Drilling is used when trenching or excavating is not practical. It is suitable for a variety of soil conditions and jobs including road, landscape and river crossings. Pipe can be made of materials such as PVC, polyethylene, polypropylene, ductile iron, and steel as long as it can be pulled through the drilled hole.

Hydro-testing

The concept behind hydro-testing is to strain the pipe, fittings and appurtenances. Any defects from manufacturing or flaws from construction are typically forced by stress intensification to reveal themselves by weeping, leaking, or rupture. Any remaining defects are considered sub-critical within a tolerable flaw size limit, and should remain stable thereafter at the lower operating pressures. Hydro-testing provides the normal level of assurance for leak integrity and the absence of flaws that exceed an intolerable flaw size. Generally speaking, the higher is the ratio of test pressure to actual operating pressure, the more effective is the test, within material stress limits. Hydrostatic pressure testing requires adopting an appropriate combination of method, pressure, time duration and length of test section.