Jul 2014
Gas Transmission
Feasibility study of onsite non-welded interlocking pipe construction
Jul 2014
Oct 2015
National Grid Gas Transmission
Dominic Feenan, box.GT.innovation@nationalgrid.com
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Network Innovation Allowance
Gas Transmission Networks
National Grid Gas Transmission is already undertaking a project to investigate alternative construction materials. This project is an evolution of that project to look at one specific technology that has been identified as potentially feasible.

In order to construct a pipeline, pipes are purchased in 12 or 18 metre lengths and transported to site. These lengths are selected in order to manage the transportation challenges (tight bends, village and country roads) to get to the construction site.

In order to produce a pipe, steel plate is produced and sent to the pipe mill. At the steel mill this plate is then passed through a manufacturing process and welded to form the bare pipe. The pipe then has to be transported to a different part of the steel mill or in some circumstance to a different factory (which can be in a different country) to get internally and externally coated. The final coated pipes are then transported to the National Grid pipeline storage or construction site. The pipes are then welded together and lowered into the ground to form the pipeline.

National Grid was approached by Sustainable Pipeline Systems Limited to see if the technology that they are developing could be of interest. National Grid has undertaken early high level conversations with Sustainable Pipelines System to understand the technology and the potential applications. While the technology looks very attractive and feasible for use, for gas transmission purposes, there are a number of fundamental steps that must be undertaken to ensure that the method can be employed safely and adequately.

Some of the early key steps are being investigated as part of this project, but it is recognised that other major works will be required before this technology can be fully accepted for use by National Grid as a feasible alternative to the current methods of constructing, operating and managing their pipelines.

The emerging technology, being investigated as part of this project, allows a mobile modular production facility to be established at the pipeline construction site. This would then allow a similar steel plate to be brought to site directly and utilised by the new equipment to form the pipeline. The new equipment uses a similar production system as some of the steel mills but produces a continuous ribbon of ridged steel material which interlocks together to form the pipeline. The pipeline can then be passed through further onsite modules to apply the internal and external coatings required, it then leaves the final module and can be placed directly into the ground without any requirement for welding pipe sections together, resulting in a significant reduction in welding overall.

Reducing the logistics associated with the pipes production and construction could also bring environmental benefits from a lower carbon footprint.

Feasibility of utilising onsite non-welded interlocking pipeline construction technique for UK Gas Transmission purposes.

One of the most significant differences between operating pipelines in remote locations compared to the UK is the increased risk associated with third party interference. This increased risk means that any National Grid pipeline has to be able to deal with a third party strike without significant escalation of the resultant damage.

This project will:

Establish, by utilising computer simulation (FEA), if the unique interlocking method used can withstand a third party strike without significant escalation.

Establish if the current design for small diameter pipelines can be scaled up for larger diameter pipelines that are typically utilised for Gas Transmission in the UK.

Establish, by utilising computer simulation (FEA), if the design method for larger diameter pipelines used can withstand a third party strike without significant escalation.

Investigate the costs associated with producing a modular system capable of dealing with the larger diameter pipelines.

Carry out a cost benefit analysis study into the actual benefits that could be realised by the introduction of the technology.

Establish the physical tests that would be required to prove the technology at the next stage of this project.

The project has been broken down into six high level stages with stage gate meetings to be held at the end of each stage. If the project is not feasible at any stage the project will be halted.