Nov 2015
Gas Distribution
Sealback II (Testing)
Nov 2015
Mar 2019
National Grid Gas Distribution
Andrew Newton – Innovation Portfolio Manager
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Network Innovation Allowance
Gas Distribution Networks
The scope of this project is to field trial the Sealback II system. This will include the development of a strategy for efficient utilisation and deployment. Sealback II integrates CCTV systems for the pre-works, inspection and installation of the installed equipment. This solution is for Low Pressure mains use only, and provide an insertion distance of up to 20m of replacement pipe with a stretch target of up to 30m, for CI4” and CI6” ‘child’ main leading on to any size ‘parent’ main.

This project seeks to successfully trial an improved method to replace short lengths of metallic main in specific locations of engineering difficulty (short lengths of main that connects onto its parent main in a major road junction) in a safe, efficient and practical manner and to agree an efficient implementation strategy for the technique.

The primary anticipated benefits of this project will be that Sealback II will:

• Reduction in operational risk and expenditure when replacing the cast iron tee sections.  Sealback II would allow the mains located in areas of engineering difficulty to be replaced: e.g. tee’s under major roads and road junctions. In particular this technique delivers a solution to the requirement to replacement short length stub pipes under Appendix F of T/PM/REP2.

  • Reduced excavation and reinstatement costs, contributing to the ‘No Dig’ targets;
  • Reduced flow stop operations on the parent pipe and associated risks;
  • Reduced cost associated with the insertion of replacement tees in large diameter parent mains;
  • Enabling the replacement of mains that are not easily accessible;
  • Reduced disruptions to the public and requirement for traffic management;
  • Reduced damage to third party apparatus;
  • Reduce risk associated with working in the highway and costs from lane rental;
  • Reduced safety risk to the public due to reduced excavations;

• Considerably reduce impact on the environment and minimize inconvenience to the road user

  • Reduce environmental impact by both minimizing all associated works as above including the requirement for imported backfill and landfill of excavated spoil and impact on trees;
  • Increased reputation for minimizing disruptions.
Successful field trials of the Sealback II technique for CI4” and CI6” diameter and up to 20m in length: with a stretch target of 27m.