WET News

4 PIPES & DRAINAGE 2018 PIPES & DRAINAGE 2018 Building the water and wastewater networks of the future Resilience and whole-life cost are vital considerations when selecting products for pipes and drainage infrastructure – and there is also scope for innovation By James Brockett tions can be seen from FP McCann (see p8). Putting the right things in the ground in the first place is only one part of optimising system Totex, however. Assessing the condi- tion of existing assets in order to know when to repair or replace them is one the foremost pieces of the puzzle, and perhaps the central challenge of tackling both leakage and sewer infiltration. Fortunately, innovation in pipe- line condition assessment has progressed I t's estimated that there are around 400,000km of water pipes in the UK (around 340,000 of which are owned by water utilities) and 350,000km of sewer pipes. That's a huge amount of infrastruc- ture, even before you start considering the countless other additional elements that make up storm water drainage infrastructure around the country. With maintenance and replacement a dif- ficult, time consuming and expensive task, all those pipes, manholes, tanks, chambers and drains need to be built to last. Since the infrastructure you put in the ground is expected to last decades, it's vital to make the right purchasing decisions at the outset. With the highly-regulated water industry approaching its 2019 price review and AMP7 asset management period, there has never been more scrutiny on how the sector spends and invests its money for the benefit of cus- tomers; and pipes and drainage are no small part of that expenditure. So what are the principal considerations when approaching this market and what are the key trends in the market at the moment? Ensuring assets last as long as possible, and hence have the lowest Totex cost, is naturally of paramount importance. Debates over the longevity of the various available materials – concrete, steel, ductile iron and high-density polyethylene – are ongoing, and different materials will be most suitable for clean water, wastewater or stormwater applications. As well as the lifespan of these materials, upfront cost, carbon footprint, ease of transport and maintenance all come into consideration. But with Ofwat placing a greater emphasis on resilience in its PR19 price review, and water companies setting demanding targets for reducing leakage, bursts and interruptions to supply in their business plans, it seems likely that ensuring a long asset life and the lowest whole-life cost will continue to be a primary concern. Modular and offsite construction is one trend that can help drive down costs, with products and systems manufactured in fac- tories to suit the specific project and sup- plied to site with minimal on-site work required. Forward-thinking suppliers are embracing the trend and are increasingly willing to work with the water industry both to standardise products and produce bespoke designs. One such company, Stan- ton Bonna, is using robotic construction to optimise its manufacturing and drive effi- ciencies in producing its Watertight Manhole System (see p14). Offsite construction methods mean that system elements that have been traditionally installed in situ, such as concrete bases for manholes, can be made precast and installed far more quickly. This saves time and money as well as environmental advantages – as illustrated by Marshall CPM's Perfect Man- hole System (see p7). Beyond pipes and drainage units them- selves, another area where meaningful econ- omies can be made at the installation stage is pipe bedding. Recent research and guide- lines from the British Precast Drainage Asso- ciation (BPDA) have indicated that many pipeline and drainage projects may be over- specifying the amount of aggregate material that needs to be used when surrounding pipes. A great example of how project designers can find more cost-efficient solu- Robots can assist in offsite construction and assembly (Stanton Bonna, p14) Precast solutions can reduce construc- tion time and Totex (Marshalls CPM, p7)

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