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Robotic inspection project reaches conclusion

After more than four years of design, development and testing, National Grid’s Project GRAID has come to a conclusion.

Project Gas Robotic Agile Inspection Device (GRAID) started in 2014, when National Grid was awarded £5.7 million (US$7.39 million) by the Office of Gas and Electricity Markets (Ofgem), the UK’s government regulator for gas and electricity markets, through an annual innovation competition.

The concept had the potential to change the face of asset management across the utility’s National Transmission System (NTS), which provides gas that more than 80 per cent of households depend on for their heating.

Construction of NTS began in the late 1960s with a 40-year design life. Over 60 per cent of these assets will be beyond that age by the end of 2030.

The traditional asset management strategy for this infrastructure relies on above ground survey techniques and existing cathodic protection on the pipes themselves. As a result, there was a reliance on good design and construction practices having been applied to the original assets; however, if corrosion was suspected, the only way of confirming this was through excavation.

In theory, Project GRAID would enable a proactive risk-based approach to the management, maintenance and replacement of these ageing assets. The concept had the potential to save National Grid’s customers approximately £60 million (US$77.75 million) over 20 years and 2,145 t of CO2 emissions per year.

The inspection robot in the test pipe.

Power in numbers

To execute the project, National Grid partnered with Synthotech, Premtech and Pipeline Integrity Engineers (PIE) to develop a robotic platform capable of negotiating its way through complex pipework geometries in its network. GRAID also had to deal with varying gas flows, while withstanding extreme pressures of up to 100 bar.

A robot was designed to deliver high quality vision of the internal pipework, with multiple cameras and a sensor package to gather data on the condition of pipework, which had not previously been inline inspected.

Synthotech specialises in innovation, engineering and technology for the utilities industry, and was responsible for developing the robotic platform. Premtech provides expertise in engineering consultancy and design management for onshore pipeline and installation projects and modelled the pipework of selected trial sites to create routes for the robot, designed the launch and retrieval vessel and the testing facility.

PIE provides asset integrity and risk management services to the oil and gas industry and was responsible for the project’s technical governance and assurance, as well as translating inspection results into an asset management strategy for the future.

Key objectives

There were four key objectives for the development of the inspection technology. GRAID needed to accurately and reliably assess the condition of high-pressure buried pipework at above ground installations using an in-pipe inspection robot, without interrupting gas supply.

The system needed to support a more proactive approach to managing and maintaining ageing assets based on the actual condition of pipework. It was also stipulated the technology should minimise the number of unnecessary excavations, stopping assets being replaced prematurely, to significantly cut carbon emissions and save money.

Finally, the device had to minimise the chance of an asset failure. In doing so, GRAID would realise substantial environmental benefit and more resilient supplies by significantly reducing the risk of a high-pressure gas release into the atmosphere.

Mission accomplished

In 2018, Project GRAID culminated in success when the robot completed a series of challenging tests. These included extensive offline testing followed by operations at two sites under live gas conditions well above 60 bar, including at one of National Grid’s COMAH sites.

The use of the GRAID robot requires numerous steps to ensure the machine’s safe operation while maximising data collection capabilities.

GRAID can operate in gas pressures up to 94 bar and flow of up to 5 m/s. Pipes of 30–36 inch (750–900 mm) diameter can be inspected; however, it will work across a wider range of inspectable diameters in the future.

A distance of 7 m is required behind the connecting flange to allow sufficient room for installation of the launch vessel and associated equipment. The system also features emergency procedures in place in the unlikely event of a system failure.

GRAID’s launch vessel complies with Pressure Equipment Directive (2014/68/EU) including PD 55000. It has short supports that allow it to be temporarily supported even in smaller pipework.

The robot’s umbilical management system (UMS) is the engineers’ connection to the robot when it’s inside a live pipe. The project team chose to install the UMS inside the launch vessel, which removed the need for a running seal.

GRAID collects data about the pipe’s condition using electromagnetic acoustic technology (EMAT), while specially developed sensors take wall thickness readings without the need for a couplant. The robot is attached to the UMS and can currently travel up to 100 m inside a pipe; however, this range will be extended in the future.

The system can navigate complex pipe geometries, including 45° rises and falls, 90° bends and equal tees. The robot uses a patent-pending magnetic pivoting track design to grip to the pipe, meaning it can be used in a range of pipe diameters.

The machine also provides eight visual feeds and the UMS gives two further feeds to engineers. Additional sensors monitor conditions including: pressure, temperature and the pitch and roll of the robot’s two chassis.

GRAID is capable of carrying out visual inspections on internal pipework. One key responsibility will be the inspection and confirmation that a ball valve – an internal sealing mechanism – is working correctly.

Site layout

Before inspection, advanced 3D modelling of existing sites is generated using a combination of laser scanning and point cloud techniques, along with an advanced component recognition software. Once GRAID inspections have been carried out, any data captured can be added to the 3D model to ensure an accurate picture of the condition of the asset.

Using this 3D model, potential inspection routes for GRAID can be assessed, with any constraints and opportunities clearly identified. Accurate drawings of the robot’s inspection route can be developed from the 3D model.

These models can also be combined with 3D models of GRAID’s connection equipment to create conceptual and detailed designs of the device’s connection points. These can include drawings, stress analyses and assessments of any hazards that may impede the robot’s operation.

Post-inspection analysis

The inspection data collected by GRAID is used to develop a detailed model of the current asset condition. Each model will provide an in-depth understanding of the asset’s condition and creating these models across multiple installations helps to understand the overall condition of National Grid’s assets and how they vary.

By carefully selecting GRAID inspection sites – and categorising installations by type, age and functionality – the project team is able to make confident predictions about the condition of the broader network. This ‘holistic’ modelling approach gives greater value to those operating assets and allows ageing infrastructure to be managed and maintained consistently across the system.

Looking to the future

“Project GRAID has officially closed, signifying the end of the Network Innovation Competition that was started four and a half years ago,” says GRAID Project Manager Dave Hardman.

“It has been an incredibly ambitious challenge from the very beginning but I am pleased to say that all of the milestones were complete. The robotic platform was designed, developed, built and tested across the course of the project and the feedback has been very positive.

“Many people said it wasn’t possible at the start but this proves that through collaboration and innovative thinking even the biggest challenges can become a reality. The future looks bright for GRAID with an implementation plan over the coming years and a proposed development to the sensor package to collect a larger quantity and quality of data going forward.”

Since the project concluded in November 2018, the project has addressed improvements, including the need to increase the speed at which the pipeline data was collected and improve the quality of the data.

According to Engineering Lead Josh Blake, EMAT worked exactly as planned, but was not without challenges.

“This technology did exactly what we needed,” he says.

“The only limitation was that due to the pipework we were inspecting being unpiggable, we couldn’t clean prior to inspection and with the sensors being magnetic they attracted debris. We developed a wiper mechanism which prolonged the inspection; however, the platform still had to be removed from the pipework at regular intervals to clean the debris from the transducers.

“This significantly increased the inspection window while also requiring increased venting of natural gas, something the whole team realised needed to change prior to integration into core business.”

Taking the above into account, the project team decided to engage with pipeline inspection company Halfwave to see whether its acoustic resonance technology (ART) could be used with GRAID. ART is non-magnetic, non-contact and also has sub-millimetre accuracy, benefits that will alleviate the challenges faced with EMAT.

Mr Blake says Halfwave is investigating how ART can help in crack detection and coating disbondment, an area of great interest to National Grid.

“Using ART on GRAID should result in an increased quantity and quality of data, providing greater insight into the integrity of the pipework and increasing confidence in the decisions made on the future of the assets, with the ultimate goal of more proactive rather than reactive maintenance,” he says.

“The new sensor technology will also drastically reduce the time taken to scan 100 per cent of the internal pipe surface, which has a significant impact on operational costs.”

GRAID ART

National Grid, the original Project GRAID partners and Halfwave have since developed a project proposal called GRAID ART. The proposal was submitted for further funding and was subsequently approved in late January 2019.

“We are currently in the process of agreeing contracts, but it is anticipated the project will be started within the second quarter of 2019,” says Mr Blake.

“GRAID ART aims to combine GRAID and ART technology, carry out testing at our offline test rig at DNV-GL Spadeadam and, finally, carry out an inspection at Bacton terminal. Providing the successful completion of the project, GRAID will be available for use on National Grid pipelines across the UK.”

Mr Blake says Project GRAID, in its current and future iterations, presents tremendous value for the UK and potential for use in other parts of the world.

“We understand we are not unique and there are other organisations with similarly ageing assets, which also need a solution to inspect our pipeline infrastructure,” he says.

“As a result, we have been engaging with other UK gas distribution networks to discuss how we can assist them with their unpiggable pipelines and how we can provide this service to them and others globally.”

This article was featured in the Summer edition of Pipelines International. To view the magazine on your PC, Mac, tablet, or mobile device, click here.

For more information visit the Project GRAID website.

If you have a project you would like featured in Pipelines International contact Managing Editor Chloe Jenkins at cjenkins@gs-press.com.au

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