Jun 2016
Gas Transmission
Valve Sealant Line Grouted Tee
Jun 2016
Jun 2017
National Grid Gas Transmission
James Beardsley, box.GT.innovation@nationalgrid.com
Click here to send a question to the contact.
Network Innovation Allowance
Electricity Transmission Networks
The proposed scope of this project is as follows:


  • Design of one Grouted Tee to accommodate the smallest diameter sealant line

  • Manufacture of two prototype Grouted Tees

  • Tooling for manufacture of new Grouted Tee seal profile

  • Development of small Grouted Tee saddle seal

  • Manufacture of multiple seals

  • Carry out accelerated seal life assessment
  • Design and manufacture Grouted Tee test rig
  • Test programme to include:
    • Preparation & Installation with standard pressure test (with PMC)

    • Under pressure drilling (PMC)

    • Insert stopple plug (PMC)

    • Carry out differential pressure test

    • Replace pipe section downstream (PMC)

    • Pressure test assembly

    • Fatigue pressure test assembly – Max 150,000 cycles

    • Pressure test to failure or agreed maximum pressure

    • Produce design, development and qualification report

PHASE 2 (Subject to positive outcome of phase 1)

  • Produce a manufacturing specification for all sealant line pipe sizes

  • Design and manufacture an epoxy encapsulation clamp for the compression fittings on the sealant line pipework assembly

  • Carry out installation and qualification testing on encapsulated pipework and compression fittings

  • Produce design, development and qualification report

  • Carry out G/19 assessment of the design and supporting documentation

  • Development/modification and approval of a NG procedure for sealant line intervention work

Develop and qualify a Grouted Tee that is suitable for sealant line intervention work.

Develop and qualify a compression fitting epoxy encapsulation sleeve.

The Grouted Tee passes the required qualification tests

The Grouted Tee seal passes the life assessment tests

The epoxy encapsulation sleeve passes the required qualification tests

Approval of new NG procedure for sealant line intervention work