Utility Week

22 | 28TH SEPTEMBER - 4TH OCTOBER 2018 | UTILITY WEEK Operations & Assets Analysis T he vast web of buried infrastructure across the UK is a challenge for the utility sector. Against a backdrop of shiing policy expectations and regulatory uncertainty, utility suppliers are under pres- sure to maintain this underground asset base while demonstrating consistently high levels of efficiency, safety and service. One of the key challenges for utilities tasked with managing buried assets is the dearth of accurate information about what is really going on below ground. Statutory records are oen lacking reliable and up- to-date information, an issue made more problematic by the UK's historic legacy of subterranean assets, from Roman sewers to Victorian drains. Nicole Metje, a co-investigator of the Assessing the Underworld project, which is part of a 25-year initiative to make street- works more sustainable, describes the maze of underground assets as chaotic. "We prob- ably only accurately know where 50 per cent of our buried infrastructure is. Of the 50 per cent that we don't know, it could be that they are only a few centimetres out or it could be metres out. That's the background challenge that we're facing," she says. "If you open the road or a junction and look at what's there, it's oen a mess. It's not just one pipe or one cable, they're all criss- crossing. It's basically a free-for-all in the underground space." Metje says the issue is exacerbated because there are no regulation guidelines: "There is advice from Street Works UK [for- merly the National Joint Utilities Group] about how far you should put assets from the curb, what depth and how far depending on the type of asset. But oen, a lot of that is not possible to do. Very few of our assets in the UK, and in a lot of countries, are laid in predefined trenches. They are just laid any- where below the ground's surface." Geophysical surveys To repair, replace or lay new pipes and cables, it is crucial to have a comprehensive understanding of co-located assets. But with statutory records oen falling short of the accuracy asset owners require, geophysi- cal surveys can help to bridge the gap in knowledge of what is buried below ground. According to Metje, who is also a senior lec- turer in the School of Civil Engineering at the University of Birmingham, the publication of PAS 128 in 2014 has had a major impact on the industry by improving the consistency of geophysical utility mapping. "Pre-2014, people oen said that there was no parity when companies were quoting for jobs because utility surveying meant dif- ferent things to different people. For some it meant collecting statutory records, for some it meant doing geophysical surveying, and for others it meant doing trial excavations," she explains. "Obviously, your tenders differ depending on what level you do, and the dif- ferent levels give you different confidence in how accurately you can map the area." However, there is still a risk of uncer- tainty. Geophysical sensing technologies have their limitations, whether it's an ina- bility to always penetrate deep enough, or struggling to resolve stacked assets or assets that are too small. Ultimately, for utility suppliers, the point of the exercise is ensuring the delivery of outstanding service, 24 hours a day, 365 days a year. For Bristol Water, this involves maintain- ing a network of almost 7,000km of water mains and services. "If something fails or service levels are not met, it directly has an impact on indi- vidual customers," says Frank van der Kleij, Bristol Water's head of asset risk and plan- ning. "As [our distribution network] is mainly situated below ground and the assets are quite diverse in terms of age, material and so on, it is challenging because you can't maintain everything. It is about understand- ing what you need to maintain, ideally just before it starts failing because you need to be as proactive as possible. You want to avoid reactive issues. "That's one of the main issues moving for- ward: ensuring that when an underground asset is failing you can anticipate where and when that failure will happen. You can then mitigate that through an intervention before it fails or before it starts impacting customers." As part of Bristol Water's drive to miti- gate risks to its asset base, the company has developed a long-term burst mains model. "The prediction model gives you a good idea of what you need to do in terms of the level of intervention to ensure that you maintain bursts at an acceptable level. That gives you a high level understanding of how much investment you need to make in terms of asset failure intervention," says van der Kleij. However, the difficulty is knowing exactly where to invest resources at any one time. "That's where you use other indicators, such as the work we are doing on increasing the number of sensors we have on the network," he explains. "The sensors will give you early warnings where a potential asset can fail. There's quite a lot of new technology on the market that can be used proactively to pick up very high levels of noise on the system, or pressure variations or flow, for example. "By using all of these indicators together you get a good indication of where potential assets could be fail- ing. You can then add other technolo- gies, such as insert- ing cameras to really understand where it's likely that your assets are going to fail first." Van der Kleij says it's an exciting time for the industry with the rapid evolution of new technologies that can make systems smarter and allow asset owners to gain more insight into their underground network. One way he believes the industry can further generate innovation is by working more closely with manufacturers and universities. "Manufacturers tend to be at the end of the process, but ideally you want to have innovation being generated through col- laboration with industry manufacturers as well as academia. That allows you to tackle a number of different areas in ways that you What lies beneath… Many utility assets are buried, but exactly where they are and how they intersect with other infrastructure beneath the surface is unclear. Nadine Buddoo reports on efforts to map the underground. "We probably only accurately know where 50 per cent of our buried infrastructure is." NICOLE METJE, CO-INVESTIGATOR OF THE ASSESSING THE UNDERWORLD PROJECT

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