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Hydrotesting or Pressure Testing

A widely accepted method for validating pipeline integrity, hydrostatic testing (or hydrotesting, as it is commonly known) is performed before commissioning new pipelines or facilities and after the repair or replacement of an in-service pipeline section.

Hydrotesting enables Gas Transmission operators to identify manufacturing flaws or other defects, mitigate risk, and establish maximum allowable operating pressure (MAOP). In addition, hydrotesting is used to re-qualify a pipeline after a class location change.

Pigging services are used in a variety of pre- and post-hydrotesting activities, including:

  • Pre-cleaning.
  • Filling with water or other testing medium.
  • Dewatering.
  • Drying.
  • Post-cleaning.
  • Chemical application.

TDW helps operators comply with regulations for the safe and effective hydrotesting of natural gas and liquids pipelines.

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Because they are efficient, effective, and easy to launch and retrieve, pigs are the preferred tools to prepare pipelines for hydrostatic testing (or “hydrotesting”) and to help return lines afterward to their operational state.

Pigging helps ensure the line is clean and free of debris that could damage hydrotesting equipment. Pigs are also used in filling the pipeline with water or other testing medium, and to dewater and dry the pipeline after the hydrotest is complete. Drying the pipeline prevents product contamination, eliminates downstream equipment freezing, and reduces the possibility of corrosion sites forming.

TDW can help Gas Transmission operators select and deploy the appropriate pigs for pre- and post-hydrotesting activities: cleaning, line filling, batching – which provides an easy-to-manage sealed interface ahead of the water or testing medium – dewatering, drying, and the application of chemicals, including corrosion inhibitors.

Cleaning pigs:

  • OptionAll™ cleaning pig Effective for cleaning, maintenance, batching, and displacement. Can be customized with attachments appropriate for clearing pipeline solids, including discs, cups, magnets, brushes, and blades.
  • VANTAGE® V cleaning pig – A multi-use pig that can be equipped with brushes to remove hard, crust-like deposits, urethane blades for removing gummy deposits, scraper discs to clean both hard and soft deposits, and magnet kits to remove ferrous material.
  • PitBoss™ cleaning pig – Designed to remove soft to medium-hard deposits from internal pits.
  • FJR/JRN cleaning pig – Equipped with wire brushes and urethane cups to remove contaminants and deposits from pipelines.
  • VANTAGE®+ cleaning pig – Multi-use pig that can remove hard internal pipe deposits such as mill scale, crust, and calcium deposits as well as thick, soft contaminants including sludge and mud.
  • REDSKIN™ foam pig – Available in five different configurations, including the REDSKIN RoughRider® pig for removing hard deposits.
  • WCK cleaning pig – Built to remove pipeline contaminants and deposits, with an outlet port at the pig’s front end to prevent loosened material from piling up. Available in a dual diameter model for cleaning multiple sizes of pipe in one run.
  • Pencil brush cleaning pig – Heavy duty, aggressive, and effective at removing black powder and cleaning deposits from internal pits. Removable bypass plugs provide jetting action to improve cleaning effectiveness.

Pigs for line filling and batching:

  • OptionAll™ batching pig Designed for cleaning, line filling and dewatering, batch separation, and liquid removal.
  • VANTAGE® V batching pig Used for batching, displacing, and cleaning.
  • X-Pig® multi-purpose utility tool Flexible and versatile all-urethane pig that can negotiate tight pipeline turns. Appropriate for cleaning, batching, and displacement operations.
  • VANTAGE® + pig – Can be used for batching and displacement. Flexible in tight bend pipelines and can traverse a 20 percent reduction in interior pipe diameter.   

Pigs for dewatering (liquids displacement):

  • UNISPHERE™ pig – Heavy-duty inflatable spheres that remove liquid hydrocarbons and water from pipelines and piping systems.
  • BiDirectionAll pig – Designed to run in either direction, can be used for air or water displacement or for cleaning when equipped with optional brushes
  • X-Pig® multi-purpose utility tool Flexible and versatile all-urethane pig that can negotiate tight pipeline turns. Appropriate for cleaning, batching, and displacement operations.
  • VANTAGE® + pig – Can be used for batching and displacement. Flexible in tight bend pipelines and can traverse a 20 percent reduction in interior pipe diameter.
  • REDSKIN™ foam pigs Designed for air removal prior to hydrostatic testing, dewater, and drying after hydrostatic testing. 

Pigs for line drying:

  • REDSKIN™ foam pigs Designed for air removal prior to hydrostatic testing, dewater, and drying after hydrostatic testing.

Pigs for application of chemicals:

Technical assistance is available from TDW subject matter experts for special circumstances or if the path to a solution requires consultation.