BISEP™ | Double Block & Bleed Isolation

Pipeline intervention and isolation can be achieved using STATS patented BISEP™. The BISEP™ range provides double block and bleed isolation deployed through a single full bore branch or hot tap penetration.

This high integrity isolation is provided by a spherical dual seal plug which is deployed from a pressure competent launcher through an isolation valve and rotated towards the flow of pressure to be isolated.

The spherical head houses twin compression seals and provides a facility to bleed and monitor the intermediate annulus. The seal annulus port proves and monitors the seal integrity before and during intervention work. The BISEP™ head utilises the same compression seal technology as our Tecno Plug™ isolation tools.

The seals are activated by a hydraulic cylinder inside the plug which compresses the seals. The resultant radial expansion pushes the seals out to seal against the pipe bore. Further application of hydraulic pressure generates a rubber pressure in the seal elements which allows the annulus between the seals to be pressure tested. Line pressure acting against the tool pressure head maintains seal pressure creating a fail-safe feature providing actuation independent of the hydraulic system. The ejection load resistance is provided by the tool’s deployment head.

Once the BISEP™ is deployed and set in position the pipeline or valve maintenance / repair can take place safely and efficiently.

DNV GL Type Approval:
STATS BISEPs™ are fully certified by DNV GL to verify that the 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 Pipeline Repair) and in compliance with the following code; ASME BPVC Section VIII, Division 2.
• Pipeline / launcher valve installation or replacement.
• Pipeline / Riser inspection, repair, replacement or decommissioning.
• Rerouting of process flow.
• Mid-line pipeline repair due to anchor drags or a dropped object on the pipeline.
• Isolate pressure vessels.
• Water or gas injection line isolation.
• Isolation of pipeline end manifolds, pipeline end terminals, subsea manifolds or skids for repair, upgrade or replacement.
Operator Benefits:
Fully verifiable Double Block & Bleed isolation through single intervention point:
• Dramatically increases safety over traditional line stop technology.
• Single operation significantly reduces costs. (Single fitting, welding, inspection, scaffolding, crane and excavation costs).
• Single operation significantly reduces workscope timescales, resulting in reduced
shutdown time.
• Single fitting allows installation in restricted access piping.
• Reduced inspection / quality control / hot work permits (single fitting).
• BISEP™ technology complies with operator double block and bleed requirements.
• Minimised production disruption on interconnected pipeline networks during valve repairs / tie-ins etc.


+47 51 73 11 00
+47 95 75 55 46
Heiamyrå 1
4031 Stavanger,
• Annular bleed port proves and monitors the seal integrity before and during any intervention work. • Isolation integrity monitored through annulus, hydraulic set circuit and body vents continuously. • Design provides axial restraint through bearing on dual clevis plates (no single point failure). • Seal annulus bleed provides Zero Energy Zone. • Dual compression seals are more compliant and have a far higher success rate than traditional cup seals particularly in pitted pipework. • Self-Energisation of seals maintains isolation integrity independent of hydraulic control circuit. • Negates the need for additional taps for bleed. • Can accommodate reinstatement pressure test. • BISEP™ isolation installed upstream of fitting, maintaining fitting in safe zone during workscope. • BISEP™ launcher ported to facilitate venting, purging and flushing of isolated section. • Can be deployed through conventional equal tee / clamp / branch.