Lowering-In
Once the pipe is welded, bent, coated, and inspected it can be lowered into the previously dug trench. This is done with specialized construction equipment acting to lift the pipe in a level manner and lower it into the trench. Once lowered into the ground, the trench is filled in carefully, to ensure that the pipe and its coating retain their integrity.
Testing
Before the pipeline can be placed into service, it must pass a pressure test (hydrostatic test) to ensure that it is strong enough, and absent of any leaks or fissures, before natural gas is pumped through the pipeline. This test consists of filling the pipeline with water and then pressurizing the line for a specified period of time (typically eight hours) to a pressure higher than the maximum at which the natural gas will be transported.
