Line Isolation

Line Isolation

In addition to saving pipeline owners and operators time and money by eliminating the need to blow down miles of line in between valves, line isolation plays an integral role in performing a variety of both planned and unplanned activities, including routine maintenance, new construction, expansions, and emergency interventions.

TDW provides a wide range of patented systems and equipment to help operators safely and reliably isolate in-service sections of pipe so they can be repaired, tied-in, connected, purged, bypassed or replaced.

The TDW STOPPLE® Train system is one example. Featuring two independent plugging heads that can be inserted into a line through a single fitting to achieve a double block and bleed isolation, the STOPPLE Train system improves safety and significantly reduces costs associated with fittings, welding, permitting, and excavating.

From large-diameter transmission mains to low-pressure distribution lines, TDW isolation equipment and services can help to ensure that pipeline maintenance operations are carried out safely and cost-efficiently in any environment.

Best used for: high-pressure lines or low-pressure lines in onshore and offshore environments.

Key features:

  • Various types of isolation equipment are available to meet the unique demands of any pipeline application, including the STOPPLE Train and STOPPLE plugging system, as well as the SHORTSTOPP® II, SHORTSTOPP PE, and SHORTSTOPP 275/500 plugging machines.  
  • STOPPLE Train technology has become the industry standard for achieving double block and bleed through a single fitting.
  • Isolation equipment can accommodate pipes of virtually every diameter, wall thickness, and material. 
  • SHORTSTOPP PE plugging system can serve as a safe and cost-effective alternative to squeezing polyethylene (PE) lines in branching, rerouting, and relocating operations.


  • Is a separate bypass necessary when using STOPPLE and STOPPLE Train plugging systems? No. After independent plugging heads have been set, product can be bypassed directly through the housing of the STOPPLE and STOPPLE Train plugging systems, preventing any interruption of service.
  • How do I know which TDW plugging machine is appropriate for my pipeline operation? TDW plugging systems can accommodate a variety of pipe sizes, temperatures, and pressures. For more information on which is most appropriate for an application, consult the graph below.

Need help selecting the right isolation system for your project? Click to enlarge the chart below.

 TDW Pipeline Isolation System Selection Chart

ShortStop 275/500

SHORTSTOPP® 275-500 Plugging System

The SHORTSTOPP® 275/500 plugging and completion machine is a highly versatile tool that can be used in a variety of applications. When used as a plugging machine, it can plug 1.5-inch lines at 19 bar (275 psi) and 2-inch through 4-inch lines at 34.5 bar (500 psi). It also can be used with SHORTSTOPP 300 D fittings (ASME Class 300).

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ShortStopp II

SHORTSTOPP® II Plugging System

The TDW SHORTSTOPP® II plugging system is designed for isolating 1.25-inch through 12-inch metal pipelines with pressures as high as 13.8 bar (200 psi). It can also be used for isolating 4-inch and 6-inch polyethylene lines.

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ShortStopp PE

SHORTSTOPP® PE Plugging System

Leveraging patented pressure control technology developed through decades of experience in pipeline maintenance, the SHORTSTOPP® PE plugging system from TDW can serve as a safe and cost-effective alternative to squeezing polyethylene (PE) lines in branching, rerouting, and relocating operations.

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STOPPLE® Plugging System

For more than 60 years, the TDW STOPPLE® plugging machine has represented one of the safest and most reliable solutions for isolating pressurized sections of pipeline.

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Stopple Train

STOPPLE® Train Isolation System

Utilizing field-proven STOPPLE® technology, the TDW STOPPLE Train isolation system features a patented double block and bleed (DBB) design that allows two independent plugging heads to be inserted into a line through a single fitting.

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