Posted: 5 September 2017

Taking it to the limit

Gas Transmission, composite pipe supports, innovation, testing, cost-saving

A hydraulic compression testing machine was used to gradually load the supports to the point of failure.

 

A new generation of pipe support, which promises to simplify the inspection process and cut costs for consumers, recently proved its mettle during a series of rigorous crush tests. Project Manager Gemma Parkes-Walley has the full story about this exciting innovation.

Innovation projects here at National Grid always set out to solve a problem, with the results bringing benefits to our customers – and our composite pipe supports project is no exception.

Gemma Parkes-Walley, Project Manager.

The aim of the project is to investigate whether composite materials – those made from a combination of plastic and other reinforcing materials – can be used for pipe supports on the National Transmission System (NTS).

Currently, all our pipeline supports are usually made of steel. And although they’re fit for purpose, they do create certain issues.

First, having a metal pipe sitting on a metal support can increase the risk of corrosion. It also creates challenges in terms of inspection and maintenance.

For example, when we have to inspect the pipe, the steel supports must be removed. They are heavy, so this can be a time-consuming job, requiring us to put in place temporary supports, unbolt the original supports, and break concrete bases. All of this takes a lot of manpower and expensive lifting equipment.

Research and investigation

After a long period of research and investigation, we established that many of these problems could be avoided by using composite pipe supports instead of steel.

We were particularly interested in a composite called GRP, or glass-reinforced plastic, which is made up of plastic resin and glass fibres. It’s very strong and has been proven in use across other industries including aircraft and boat manufacture, so it was a natural choice when considering new materials to trial in the gas industry.

We teamed up with project partners Premtech and gave them the brief to develop a GRP support strong enough to be used as a replacement for steel.

Proving its mettle

By nature, GRP is lightweight and won’t corrode when exposed to air and water. So it already has a natural advantage to metal.

The new design has further benefits. For example, GRP allows the support to be removed without needing to break the concrete plinths below them, which drastically reduces the number of technicians and level of equipment required on the job. The design also includes a smart feature that allows water to drain away from the pipe and support rather than forming pools, which can happen on the current supports.

Above all, this clever design allows for the easy removal and replacement of the support, making pipework inspections quicker and simpler to achieve than before.

Breaking new ground

During the initial FEA images like the above were created.

Up to now, composite supports have never been used in the UK gas industry. As a consequence, the supports will be put through detailed design, testing and analysis.

The first stage of testing involved us creating something called a finite element analysis (FEA) model, to predict what sort of loads these supports could potentially take. Stress analysis experts Andrew Francis & Associates supported Premtech on this vital stage of the project.

FEA is a powerful computerised tool that allows us to assess complex engineering structures that are subject to internal or external loads. In simple terms, it estimates the failure point and areas of weakness and fractures that could occur under different weight loads.

Real-life setting

While these results are extremely useful to us, we need to verify their accuracy in a real-life setting. And that’s just where we are at the moment, having recently carried out crush testing on two specially manufactured supports.

As part of the crush testing process, two supports were put through their paces by a hydraulic compression testing machine. The supports were loaded, bit by bit, to determine what load they could take, pushing them to the point where they would eventually fail.

The crush testing is important because it gives us confidence that, when we put these supports on to the network, they’ll be able to take the load we predicted using the FEA.

The crush testing was successful. The results aligned closely with the FEA models we’d created, giving us a good degree of confidence that our models are accurate and will provide an excellent understanding of how they’ll behave and perform in a real-life situation.

The output of the project is an approved design specification which can be used where required to replace existing steel supports and also be included in the design of new sites.

Radical reduction in costs

This innovation will bring significant benefits; improved safety and reliability and reduced costs.

The identification of pipe corrosion under supports and any resulting repairs will become easier to carry out, meaning any issues should be resolved more quickly.

Currently, most support replacement and painting jobs are complicated and costly. This new design will allow supports to be removed, and pipework inspected in faster timescales. It will also avoid the need to re-coat the supports and re-cast new concrete plinths, radically reducing the costs associated with these works.

The focus in the coming months will be finalising the design and the manufacturing specification of the composite pipe supports.

It’s fantastic to be part of this innovation project, getting a chance to influence a new design, impact how the business will operate in the future and ultimately pass on the benefits to our customers.

To learn more about the supports and see the crush-testing process in action, watch our video below.

Stage set for flagship competition
“The clever design allows for the easy removal and replacement of the support, making pipework inspections quicker and simpler to achieve than ever before”

Gemma Parkes-Walley, Project Manager.