Apr 2014
Gas Distribution
Bond and Bolt Saddle System
Apr 2014
Feb 2019
Hector Salgado, Innovation Project Manager
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Network Innovation Allowance
GD - Mains Replacement
Maintenance & Inspection and Gas Distribution Networks
The scope of this work is to design, develop and test a bespoke adhesive that will form a joint, which eliminates the need for the saddle to be plugged off. The solution has the potential to reduce the size of excavations required when completing branch drilling operations, which will in turn bring the time and cost savings that are already being achieved to a much wider range of applications. The project will:

  • Design and develop proof of concept.

  • Design prototype adhesives.

  • Manufacture and test prototype adhesives in specially constructed test rigs.

  • Select three adhesives for external testing.

  • Conduct laboratory based study representative of in service conditions.

  • Initial design of saddle flange incorporating the chosen adhesive.

  • Manufacture specialist saddle flange assembly.

  • Conduct a field trial of the three units on various mains sizes for product verification. SGN’s Southern site location is yet to be determined.

  • Produce a draft work procedure and technical report on the development of the equipment for review by SGN subject matter experts before final version is produced.

  • Conduct a full scale assessment prior to transfer to business as usual.

A change request was submitted in February 2016 to allow for the required additional testing on the fittings secured by Bond and Bolt technology, post-installation. The initial test plan allowed for testing on live mains only. As the project has progressed, it has been determined that there is a requirement to carry out trials on dead mains before progressing to live field trials, these tests were identified after the completed initial 1000 hrs of laboratory testing and could not have been foreseen prior to the project commencing. It has also been deemed prudent to remove the connection made on the dead mains and test them in laboratory conditions against the mechanical specifications identified in the first stages of the project. The additional testing may take a further ten months, resulting in an amended project end date of November 2016. This additional testing will also incur extra costs, which will be provided following determination via a thorough tendering process.

The objectives of the project are to:


  • Design and develop proof of concept bond and bolt saddle system to be used in conjunction with the existing branch drilling equipment.
  • Develop working prototype and carry out off site testing.
  • Carry out field trials to comprehensively review the new solution in a live gas environment.
  • Carry out a detailed cost benefit analysis for field trials.
  • Provide relevant information to the other Network Licensees.
The success criteria for the project are to:

  • Consider a criterion relating to development of the product as well as practices.

  • Develop operational practices to support a bespoke adhesive that will form a long lasting joint to improve a temporary bond and bolt saddle system.

  • Identify the extent to which adhesive solution minimises the size of excavations required when completing branch drilling operations.

  • Produce and disseminate learning around the expected cost and time reductions.

  • Provide Network Licensee with the technical report produced, which will incorporate information on the research, development and field trialling of the new adhesive and saddle.

In order to determine whether this project has been successful or not at various stages, the project must progress through a number of stage gate milestones. SGN’s Project Manager will evaluate the performance against the requirements before approving progress to the next stage.