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Pressure Pipe Relining

Semtex Trenchless Solutions provides specialist assessment and rehabilitation solutions for pressure pipelines used in water, wastewater, fire, industrial, marine and offshore applications.

Pressure pipe relining differs from gravity pipe lining because the rehabilitation system must resist internal operating pressure as well as surge, vacuum, temperature, movement and connection loads. Each pipeline is assessed individually before a lining system is selected.

Applications include:

  •  Potable and raw-water pipelines

  •  Fire mains and fire-protection pipework

  • Wastewater rising mains

  • Industrial process pipelines

  • Cooling-water and service-water systems

  • Marine and offshore pipelines

  • Oil and gas facility pipework

  • Chemical-transfer and other specialist pipelines

Rehabilitation options

Depending on the pipeline and operating conditions, rehabilitation options may include fibre-reinforced flexible liners FFRP, close-fit liners, reinforced pressure CIPP, thermoplastic systems, internal epoxy or polymer lining, composite repairs and other manufacturer-specific pressure-rated solutions.

The selected system may be designed as an independent structural liner, an interactive liner that relies partly on the host pipe, or a protective internal barrier for corrosion control and service-life extension.

Technical assessment

Important design and constructibility inputs include normal and maximum operating pressure, surge pressure, vacuum conditions, pipe material and remaining wall thickness, internal diameter, bends and fittings, connection details, temperature, chemical exposure, flow requirements, shutdown duration, access and required design life.

The pipeline must also be assessed for cleaning and preparation requirements, liner insertion length, end restraints, branch connections, valves and transitions. Where required, specialist manufacturer and engineering support is incorporated into the design.

Installation and quality control

A pressure-pipe rehabilitation project may include isolation and dewatering, internal inspection, surface preparation, dimensional verification, installation of the selected liner or coating, engineered end terminations, cure control, pressure testing, final inspection and project-specific quality documentation.

Not every pressure pipeline is suitable for relining. Where the existing geometry, condition, access or operating requirements make relining unsuitable, we can provide practical advice on alternative rehabilitation or replacement options.