BISEP® Line Plugging

0 Reviews
6 Deploys

Hot Tap Installed Double Block and Bleed Isolation

Page last modified
February 22 2024

STATS BISEP® offers pipeline operators a solution using industry-leading technology for temporary line plugging. Achieved using patented and DNV Type Approved technology, the BISEP provides a fail-safe double block and bleed isolation deployed through a single full bore hot tap intervention, without the need for additional hot tapped bleed or vent ports. The BISEP offers significant safety advantages over traditional line stop technologies, with the hydraulically activated dual seals providing leak-tight isolation of live, pressurised pipelines. 

This high integrity isolation is provided by a spherical dual seal plug which is hydraulically deployed into the pipeline from a pressure competent launcher, through a dual seal isolation valve. The seals are hydraulically compressed resulting in radial expansion against the pipe bore. During isolation barrier proving, each seal is tested independently with full pipeline pressure in the direction of the expected pressure differential, proving both seals of the double block isolation are leak-tight. Following successful seal proving, the vented annulus void is then closed and monitored confirming isolation integrity throughout the isolation period.

The line pressure acting against the BISEP pressure head offers a fail-safe feature by providing actuation independent of the hydraulic system. The ejection load resistance is provided by the BISEP deployment head.

Multiple BISEPs can be used to provide mid-line isolation of pipeline sections and the introduction of a bypass line allows sectional isolation to take place without the need to shut down the entire system or affect product flow.

The BISEP can be configured in the Dual Set (DS) configuration which includes an integrated bypass through the launcher, ideally suited to lower pressure applications. 

Pros & Limitations
Leak-tight double block and bleed isolation
Monitored dual seal isolation - proves seal integrity before and during intervention work
Dual elastomer seals provide higher integrity isolation than traditional cup seals
Hydraulically activated seals can be manipulated to improve performance when sealing in pipes with issues such as ovality and internal surface irregularities, ie weld seams, corrosion, erosion
Self-Energisation of seals maintains isolation integrity independent of hydraulic control circuit
Ability to accommodate reinstatement pressure test against the rear of the plugging head
BISEP deployment housing ported to facilitate venting, purging and flushing of isolated section
Clamp or fitting remains on the pipeline after BISEP is removed.
Specification Title Specification Description
Size Range
3" to 53"
Pressure Range
Up to 153 bar / 2220 psi
DNV Type Approval: design criteria satisfies the requirements for Pipeline Isolation Plugs to provide dual seal and isolation in accordance with Offshore Standards; DNV-OS-F101 (Submarine Pipeline Systems) and recommended Practices; DNV-RP-F113 (Subsea Pi


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Technology Readiness Level


Development Technology demonstration Mature / Proven
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STATS Group are market leaders in the supply of pressurised pipeline isolation, hot tapping and plugging services to the global energy industry. DNV type approved isolation tools provide leak-tight double block and bleed isolation that enables safe and efficient maintenance and repair of onshore, topsides and subsea pipeline infrastructure.

Process Plant Solutions offer hot-work barriers and localised hydrostatic weld test tools to verifying the integrity of welds or fittings, reducing system downtime, minimising environmental impact and increasing worksite safety. Mechanical repair clamps and pipe connectors replace the need for welding, significantly reducing expenditure and associated risks with hot-work providing the tie-in, repair or end-capping of pipelines.

STATS has gained an excellent reputation for providing a responsive, client-centred approach combined with expertise and innovative products which:

  • Drive higher levels of safety in the industry  
  • Enhance environmental performance by reducing flaring and venting activities
  • Improve asset performance while reducing system or plant downtime
  • Support the industry transition to a low carbon future

Project management and engineering services are provided to support client needs including turnaround scopes, feasibility studies and contingency planning. In-house expertise extends over the entire lifecycle of hydrocarbon assets from construction, maintenance, asset life extension, through to decommissioning and on to hydrogen transportation, carbon capture and storage.

STATS provide high quality, fit-for-purpose solutions to ensure that the pipework and pipeline infrastructure of its clients meet the technical, safety and environmental standards required.

Headquartered in Aberdeen, Scotland, STATS Group operate globally through a growing network of operational bases, including Canada, USA, Qatar, the UAE, Oman, Saudi Arabia, Malaysia and Australia.  

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