processing | Infrastructure pipe
of pipe – that’s 2.5 times more,” he said. There were challenges to the project – not least that the pipe should be made onsite, in a very remote location. Pipes were laid under the road, and needed to withstand loads of up to 18 tonnes. Many of the pipes passed under crossroads – and one of the challenges was to analyse the behaviour of the pipe in these locations, he said. The pipe has now been in place for 10 years and is
delivering potable water to around 1m people, he sad. Overall, although Argentina uses relatively small amounts of plastic pipe, Guevara says it will change as standards improve. “There are many regulations governing the pipe, but not so many regarding installation,” he said. “Even the toughest pipes require good installation.” He said that there is an Argentinean standard for
Above: Wavin says that PVC-O pipe delivers significant weight savings
As well as developing innovations in project manage- ment – in order to install pipe with minimal disruption, for example – the project also relies on a new type of pipe from GPS. The company has, for the first time, produced 800mm PE100 gas pipe in the UK – for which a new approval process was needed. “Prior to this, the largest pipe was 630mm,” O’Sullivan told delegates.
The pipe is a solid-wall design – with no layers – and
is highly crack resistant. GPS also developed an innovative conical ring
coupler, which joined pipe ends together more efficient- ly. It had a smaller working footprint, required no clamps and improved both pipe preparation time and fusion time. It was used for 355-1200mm diameter pipe, and
featured an inner heater coil. It also integrated pipe re-rounding by using assembly wedges – and cut the gap size close to zero. The first phase of the project was completed 21 days
early, and gas has now been flowing – without incident – since September 2016, he said.
Long-term behaviour Pablo Guevara, chief technical officer of Argentinean pipe manufacturer Plastiferro Tubos, revealed details of a project to assess the long-term behaviour of 1.8m diameter pipes that were used in a demanding struc- tural application. The pipe was structural helically wound PVC pipe, in sizes of 350 to 2300mm. In 2006, it installed a 33km pipe at a cost of around US$28m – working out at around US$840,000 per km of pipe installed.
“This type of installation, using other materials and similar conditions, would cost around US$2.1m per km
20 PIPE & PROFILE EXTRUSION | June 2017
pipe installation, called IRAM 13460, but only one of four parts has so far been published.
Long-term testing Pipes are normally tested before they go into the ground, to ensure that they will last for their specified lifetime. However, one project has recently dug up old pipe samples, to assess how much useful life they have left in them. A project run by Dutch testing institute Kiwa
Technology and others has tested more than 500m – and 49 joints – of gas and water pipe that had been subjected to various conditions. “Utility companies want to know how much longer their buried pipe will last,” said Albo van Hateren, account manager at Kiwa. Kiwa carried out nine excavations of 110mm water pipe that was used at 3.5-10bar, the same number for the same pipe at 0.09-1 bar, and nine more for 32mm gas pipe at 0.8-1bar. Each excavation extracted 10-30m of pipe. Samples were then subjected to a range of physical tests including hydrostatic pressure. Tests showed that residual PVC pipe quality – after 30-50 years of service – was still up to the required standards. He said there were some differences between old
and new pipe, including a change in the brittle-ductile transition temperature. “The reason is simple: over time, PVC producers
have made better products – and this will continue” he said.
Rapid crack propagation (RCP) tests also showed that the old pipes were performing well – with even pipes from 1971 showing no signs of ageing. “Utility companies want to know if they should dig up their old pipes now and replace them,” he said. “Our conclusion is that they should keep them in the ground
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PHOTO: WAVIN
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