Regions and Basins

Appalachian Basin commissioning and decommissioning work

Commissioning and decommissioning use much of the same equipment and almost none of the same assumptions.

The commissioning sequence

In outline: clean, gauge, fill, test, dewater, dry, purge, and introduce product. Each phase hands a condition to the next, and each handover is where schedule is lost.

Cleaning ends with a stated debris criterion, not with the crew running out of pigs
Gauging proves the bore for whatever tool follows
The test proves strength and tightness, and produces the life-of-line record
Dewatering ends with a stated residual condition, not merely with pigs received
Drying ends on dew point plus a soak, not on an active sweep reading
Purging ends on a sampled composition at the discharge

Where decommissioning differs

Decommissioning starts from a line full of product, of uncertain internal condition, with records that may be decades old and incomplete.

The pigging is dirtier, the returns are hazardous rather than merely inconvenient, and the disposal question is the dominant one. Purging to an inert condition and proving it by sampling matters more than anything about pressure.

Records cut both ways

On commissioning you are creating the life-of-line record required under 49 CFR 192.517 and 195.310.

On decommissioning you are relying on records somebody else created, often long ago, to tell you what is in the line and what the pipe is made of. Where those records are thin, verification work replaces them, and that work is the schedule.

Regional realities

Appalachian terrain drives segment count on both. Access is frequently the binding constraint — a segment break in a location a vacuum truck cannot reach is a different problem from one in a field.

Winter work brings the near-zero water expansion coefficient into the analysis, and the working day shortens while the holds do not.

Who does this work

HydroTech Testing Services is a pipeline commissioning and decommissioning services company based in the Appalachian region, serving natural gas and hazardous liquids operators across western Pennsylvania, the tristate area, and internationally.

The field crews who plan and execute this work wrote the field book and teach the certification courses built on it.

Standing noteThis is educational reference material, not engineering advice. Regulations are revised continually; the editions in force at the time of a project govern, and every project requires its own qualified engineering analysis and the operator’s governing specifications.

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From Proper Pigging, the hydrostatic and nitrogen test field book, and the HydroTech certification courses built on it.