Dec 2013
Gas Distribution
Starline/Marwin Valve Bolt Replacement
Dec 2013
Oct 2017
Mark Skerritt, Innovation Project Manager
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Network Innovation Allowance
GD - Reliability and maintenance
Gas Distribution Networks
The scope of the project is as follows:

- Developing the Equipment

  • Design and develop proof of concept design

  • Develop prototype design with aid of finite element stress analysis

  • Produce prototype design

  • Undertake high pressure performance/strength test on prototype.

- Undertake a field trial in a location in Scotland.

- Producing a Work Procedure that provides detailed step-by-step instructions on the use of the equipment

  • Produce a draft Work Procedure for review by SGN subject matter experts

  • Produce final version of Work Procedure incorporating feedback from subject matter expert review.

- Producing a formal report on the development of the equipment

  • Produce a draft report

  • Produce final version of report.

Additional time is required due to unexpected technical issues; it has been very complex obtaining a suitable section of pipe work that meets the criteria for acceptance testing. A site was selected but due to operational requirements there was a limited amount of time that the site could be decommissioned to remove the test pipe work. The operation to remove the section of pipe work has now been completed and we can now move towards the testing phases of the project.

A further six month extension (revised end date from October 2015 to April 2016) was required due to delays involving the material selection and identification of a manufacturer for the clamp; primarily because of the need to ensure it meets the stringent design and integrity requirements set against it, leaving no doubt that it is ultimately safe for application on an affected high pressure Starline/Marwin ball valve. This has taken more time than anticipated due to the specialised materials being used, the high degree of manufacturing accuracy needed and the complexity of the associated processes, particularly the heat treatment processes involved with the clamp’s manufacture.

The objectives of the project are to:

  • Design and develop proof of concept of a solution which enables the bolts in a 1” Starline/Marwin valve to be replaced whilst pressurized.
  • Develop working prototype and carry out off site testing.
  • Carry out a field trial 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 the replacement of corroded bolts on 1” Starline/Marwin valves whilst pressurised

  • Identify the extent to which bolt replacement using the new Method minimises the impact and loss of supply to the network

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

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.