May 2016
Gas Distribution
Small Diameter PE Flowstop
May 2016
Nov 2020
Alex Stewart, Innovation Project Manager
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Network Innovation Allowance
GD - Reliability and maintenance
Maintenance & Inspection and Gas Distribution Networks

This project will involve work alongside WASK / Crane Ltd to carry out design, development and testing of a new electrofusion bag saddle, to current Gas Industry Standard GIS/PL2 (Parts 1,4,5 &6), to expand the range of the existing process down to 90mm PE. It will look to verify its suitability as an alternative system to conventional squeeze off on small diameter PE mains. The outcomes of the project will be:

  1. Full development, offsite and onsite testing of an electrofusion saddle to GIS/PL2 (Parts 1, 4, 5 & 6) in the range 90mm-250mm PE.

  2. Design and development of an electrofusion clamping system for use with the new saddle design for use in 600mm core excavations.

  3. Design and development of the drilling system and closure plug for use on the newly designed bag off saddles.

  4. Development of flow stopping equipment for use in the new design of bag off saddle, including bypass equipment.

  5. Pre-trial testing to prove compliance with GIS/PL2 (Parts 1, 4, 5 & 6) and production of relevant Work Instructions

  6. Off Site Field trials and any required amendments to Work Instructions

  7. Live field trials and any required amendments to Work Instruction

The objectives of the project are to:

  • Produce and test equipment to carry out PE flowstopping on Tier 1 assets and prove compliance with GIS/PL2 and that the equipment is suitable for use in a 600mm core excavation.
  • Provide report detailing test results to allow field trial documentation to be produced.
  • Completion of full suite of field trials to be carried out on a range of diameters in both conventional and core excavations to prove the equipment to carry out PE flowstopping can be of benefit in a ‘live gas’ scenario.
  • Completion of final project report.
The success criteria for the project are to evaluate and test the new small diameter bag off equipment against conventional flowstop techniques and compare the performance in terms of:

  • Evaluate the suitability of the equipment as a replacement for conventional flowstop methods

  • Confirm compliance with GIS/PL2 (Parts 1,4,5 & 6) for use of equipment in extended size range

  • Demonstrate the effectiveness of small diameter PE bag off as a permanent replacement for conventional squeeze off in both conventional and core excavations and across the extended size range.

  • Evaluate performance versus conventional techniques detailing benefits of the new technique versus conventional.

  • Produce acceptable detailed final report including test results showing compliance with standards and field trial results showing detailed potential savings.

  • Disseminate information and project outcomes