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NETWORK / 27 / SEPTEMBER 2016 Antony Green, vice- president for utilities and infrastructure at DNV GL says: "The corporate memory is somewhat lacking because the people who have dealt with these incidents in the past are long gone, so what is the risk of a failure on a gas main? We can actually demonstrate that at Spadeadam." Network witnessed several small explosions, including the ignition of 6kg of propane gas in an 80m 3 volume, ignited at one end with a spark generator. The force is incredible, and truly does need to be felt for the consequences of such an event to be understood. Such an explosion is at the small end of the scale; the force from the kind of explosion that can send a 13-tonne section of pipe flying is unimaginable, and frankly frightening. To prevent this dangerous industry complacency, Spadeadam has invested £3 million in a new training centre and demonstration area and is developing a range of courses aimed specifically at GDNs and National Grid. "This is a major investment in the site, recognising that there is a real need in the industry to push forward in this area. It can be used for hazard awareness, industry conferences and research." Alongside training, the team at Spadeadam are regularly called in to perform independent investigations at incidents for GDNs, such as the fire at Holborn in London. In that case the affected gas pipeline took a full two days to cool. A lot of the explosion research that underpins the fundamentals of incident investigation was also developed at Spadeadam. "That's why we are unique," says Green, "a lot of people can model things, but we can model and test the real world impact of that – and we can recalibrate our models to match." Spadeadam also has a long history of being the place where GDNs test their innovations before they are used on the network. The robotics in National Grid's Project Graid (see right) are due to be tested here. The site's remoteness also allows for complete confidentiality with these projects. In the future Spadeadam may also have a role in testing carbon capture and storage technology, necessary for the decarbonisation of gas generation, because it is one of the few places where gas release work can be performed. N The conditions inside a high-pressure gas pipeline are hostile, but National Grid Gas Transmission (NGGT) is attempting to design a robot that can survive it. The gas robotic agile inspection device (Graid) project is designed to revolutionise asset management – from predictive modelling to visual inspection of assets buried beneath the ground. Such a robot will have to navigate complex pipelines while withstanding up to 100bar of pressure during times of peak flow in the pipeline. If successful, says NGGT, the robot at full operational capacity is likely to save about £60 million over 20 years by avoiding unnecessary excavation while also cutting carbon emissions. Since January 2015, the £5.7million network innovation competition project has successfully completed the design stage and is about to move into a two-phase field trial. The robot has been modelled on the aerodynamic shape of a dolphin and will use magnets to resist the forces of peak gas flows and to navigate round the full circumference of the pipeline. The robot will be driven through the pipework by a human engineer to carry out visual and physical inspection of otherwise inaccessible buried sections of the network. To be deemed successful by Ofgem, the robot must be able to travel a minimum of 100 metres and navigate two bends. This will be tested during a series of field trials due to take place in 2017 which will be split into two phases, offline and online. Offline trials will take place in a purpose-built test rig that replicates the most common geometry features of high- pressure buried pipework. The rig will be pressurised to the same level and gas flow velocities will be representative. The offline trials will provide a safe environment to test the robot's capabilities, refine operating procedures and validate safety and recovery measures. Successful completion of offline trials will provide the necessary assurance that the robot is safe to launch into a live site – under live gas conditions – in online trials. NGGT says Spadeadam was chosen as the location for the offline trials because of the experience of the site staff in experimental engineering. The facility is an ideal environment in which to build the test rig and conduct trials in a safe environment with the expertise of DNV GL's engineers on site. The rig is currently under construction and due to be completed in January 2017, with offline trials starting in late February 2017. H i g H - p r e s s u r e i n s p e c t i o n The latest technology for inspecting high-pressure gas pipes will be trialled at Spadeadam A confined vented explosion of 7kg of propane in a chamber measuring 81m 3 with a spark generator