This approach provides a risk rating for the benefits, in this case the risk was assessed by National Grid as ‘low’, meaning that National Grid can have a high level of confidence in the results it will achieve.
There are around 300 locations on the National Transmission System where gas pipes pass through reinforced concrete walls, for example into valve pits. Currently, several types of seals are used to prevent contamination by water or soil, but when these seals fail, technicians face a major task to fix the problem.
National Grid has found that Haydale’s CTP represents a huge step forward in safety and efficiency, solving a major problem for the national gas transmission network at a reduced cost over the system’s life-time. The solution allows easy access to transition pipes at pit wall transitions for inspection and maintenance. Working in conjunction with National Grid, the innovative CTP seal units can be used to plug the gap between the pipe and the wall. It means that technicians can easily remove the unit and check the pipe for corrosion or damage. The CTP can then be replaced quickly in one simple operation.
Financially, the benefits of installing a CTP are significant especially when viewed over the entire design life of the unit. Taking less time to inspect the pit wall area with a CTP fitted means that just under £230k could be saved over a design life of 50 years per unit installed. This is comparing an inspection using the traditional methods with the composite solution.
In addition to the cost benefits, National Grid estimates that 700 fewer hours of ‘at risk’ activities will be needed for each CTP during its design life. Working on the pit wall requires technicians to work inside a pit which may be several meters deep. Benefits can be tracked after the first inspection and continue for the entire design life of 50 years per unit, this can subsequently be extended further following a simple replacement of the seal around the CTP.
There are also environmental benefits and National Grid have calculated that the new approach will save 12 tonnes of carbon equivalent (CO2e) for each CTP over its 50-year lifespan. This is determined by examining tasks such as excavating soil to expose the pit wall and generator power needed on the site.
Two key compressor sites have already undergone large-scale works where National Grid have utilised the new CTPs. In total, eight new CTPs have been pre-fabricated and will be installed during the construction of the pit wall, further reducing installation costs. These units, along with one that was installed as part of the original trial, will start to provide benefits after their first inspections. David Banks, Chairman at Haydale, commented, “With 9 CTPs planned for installation by the end of 2019, we look forward to seeing the benefits recognised by National Grid. We look forward to continuing our work with the utilities industry, where the benefit of both composite materials and graphene are now being appreciated.”
Keith Broadbent, CEO at Haydale, commented, “Haydale is pleased to be working with National Grid on this system which is a huge step forward in safety and efficiency for the gas network. With £228,000 average savings per CTP design life and 700 fewer hours carrying out ‘at risk’ activities for each CTP over 50-year period, it is clear to see the benefits that the system offers to the customer. We look forward to working with gas infrastructure owners worldwide who can also benefit from the product.”
Paul Ogden, Senior Civil Engineer at National Grid, commented, “Over a six-year period, National Grid expects to install about 60 CTPs on the National Transmission System. This will significantly improve safety as well as creating savings of up to £5 million in the next five to 10 years.”