Water's Pipe Dreams

From nanotechnology coatings to special offshore innovations, technology is playing a bigger part in pipe production. Gareth Evans looks at where pipes are leading to in 2010.

Pipes are as old as water technology gets. Back in 3,200BC – some 500 years before work began on the pyramids – inhabitants of the Skara Brae settlement on the UK's Orkney Islands were already enjoying the unexpectedly ancient luxury of the world's first plumbing. Despite the antiquity of that first water pipe, and the long history of subsequent civilisations that adopted and adapted this simple expedient, piping technology has moved on a long way.

While the fundamental essence of pipe-work may be unchanged, today's incarnations cover a range of applications with an unprecedented suitability for purpose that would have been inconceivable to those ingenious water engineers of the Neolithic Period. Much of this ongoing trend comes down to the characteristics of the materials now available, coupled with recent developments and innovations in the sector.

Concrete advances

Given the current economic climate, the need to contain expenses has become an increasingly compelling driver across the broad spectrum of infrastructure projects. For sewerage and drainage schemes in particular, this emphasis has helped reassert some of the innate advantages of concrete products, for improvement programmes and de novo developments alike.

Compared with many of the other viable alternatives, sourcing and producing concrete drainage pipes comes at a relatively low cost.

"You don't have to build the whole structure of the underlying system around the pipeline."

Since the material provides its own high inherent strength, it remains markedly less susceptible to sub-optimal installation. As recently retired water engineer Alan Boulanger explains, this brings two major advantages.

"You don't have to build the whole structure of the underlying system around the pipeline, and the bedding demand is reduced, too," he said. "If you can lay your pipes with lower grade aggregate, save on the transport and cut the cost of spoil removal, that makes a difference and soon mounts up for every metre of pipe. It's a potentially big saving."

Unsurprisingly, this has played well to a construction industry heavily mired in the downturn and looking for effective but economic solutions. For example, reduced installation costs have featured significantly in the rising popularity among water companies and contractors of elliptical concrete pipes for drainage and flood prevention projects, particularly in high water table areas with shallow surface gradients.

With flooding likely to be one of the issues of the decade, and the recovery shaping up to be a slow one, the trend is likely to continue.

Ductile developments

When it comes to small diameter piping, one material pre-dominates – plastic. However, after years of development, the new Blutop ductile-iron pipe from Saint-Gobain PAM, might be about to change all that. Lightweight and with a wall just 3mm thick, this small-bore piping is a versatile product, described as offering all the 'traditional values and long-term performance of ductile iron with the modern values of plastics'.

The combination promises leak-free reliability, simplified handling, low installation costs and excellent water quality, and it is already racking up a respectable client list of users keen to capitalise on its potential, including the likes of the City of Paris and Wessex Water.

"The revolution in coatings has seen a range of innovations begin to make their way into real-life applications."

The technical specifications are impressive: a 25 bar operating pressure, with a 3 bar pressure resistance safety factor, a 6° maximum angular deflection at the joints and capable of being laid from 0.7m to 45m. Available in 90mm, 110mm and 125mm – with weights of 6.1, 7.5 and 8.6 kg/m, respectively – and factory tested to 40 bars, Blutop is being touted as "the high-performance solution for potable water distribution".

For a company more traditionally associated with large diameter ductile piping, Saint-Gobain's latest offering certainly represents a departure, but business development director David Smoker believes it is one that "will generate new market".

Coatings revolution

If so, then at least some of the success will be down to the current revolution underway in coatings, which has seen a range of innovations begin to make their way into real-life applications. In Blutop, an advanced zinc aluminium externallayer complements a 300μm-thick, high-tech internal coating of high-impact resistance Ductan thermoplastic.

Developing the 400g per square metre, 85 / 15 zinc / aluminium alloy alone took a reported 15 years and the finished product represents the first time that the company has launched a pipe, which simultaneously features inner and outer novel linings. Elsewhere, the boundaries are being pushed even further.

Although it is some distance from the market, recent research at Duke University, North Carolina, USA, could herald novel nanotechnology coatings for the water industry, if their work on the anti-bacterial properties of C60 buckyballs continues to bear fruit.

To date the team has demonstrated that coating the inside of pipes with these tiny carbon particles not only directly impairs microbial attachment and biofilm formation, but also inhibits bacterial respiration.

"This respiratory inhibition and anti-attachment suggests that this nanoparticle may be useful as an anti-fouling agent," says Dr So-Ryong Chae.

Although the mechanisms involved are not fully understood at the moment, nor is it clear how effective the proposed coating would be in long-term use, the prospect of addressing one of the industry’s most enduring problems is clearly an appealing one.

Offshore challenge

There is probably no more challenging environment for any kind of water pipe than in offshore and marine applications and arguably the best exemplar of that lies some 240km southeast of New Orleans in the Gulf of Mexico – the Thunder Horse oil and gas platform.

"There is no more challenging environment for any kind of water pipe than in offshore and marine applications."

Meeting the sewage treatment needs of the largest installation of its kind is obviously a big undertaking and it is a task that Severn Trent De Nora's Omnipure system has managed since first being installed back in 2005.

One of the principal factors behind that enviable performance has been the reliability of the piping selected for the job.

Having had occasion to test a range of other materials in the role over the years, including PVC, GRP and lined metal pipes, Severn Trent De Nora found that only Corzan CPVC achieved the level of consistent performance that their system demanded.

"Our equipment is working in a saline atmosphere and pumping raw sewage, seawater and sodium hypochlorite at pressures up to 150psi in some cases," says the company’s marine and offshore product manager Dana Casbeer. "All of these are highly corrosive."

For installations far from land, and subject to tightly regulated effluent emissions standards, reliable water treatment is essential. Like every other application across the water industry, it seems that success comes down to picking the right pipe. With innovation running high across the sector, it seems there will be no shortage of choice.