MATERIALS | PE100


Right: Agru says that its pipe is often used in seawater environments


All PE100+ members – and PE100+ accredited


or interested laboratories – were invited to take part, and 18 laboratories participated anonymously. Compared to other RRTs performed on the ISO1167 standard, this one showed slightly smaller variations in reproducibility and repeatability, said the association. No laboratories involved in the RRT were classified as statistical outliers. In addition to the statistical evaluation of the


pressure test results, a deeper investigation was also carried out. This was a questionnaire on the impact of the water quality, sample preparation, equipment used and experience of the lab. “The questionnaire showed that not all the labs followed the ISO standard precisely,” said PE100+. “There is certainly room for a further improvement of the reproducibility of the hydrostatic pressure test results between laboratories.” The RRT results will be used by standardisations


committees to further improve the pipe standards, said the association. Separate to this, the association recently expand-


ed into Russia by welcoming a new member. Kazanorgsintez, a Russian polymer producer established in 1958, offers a range of materials – including HDPE for pipe. Its PE2NT11-9 grade was recently tested and approved using the three main mechanical performance tests – CRS, SCR and RCP – and is now listed as PE100+ quality material. The grade appears on the association’s latest list


of materials, which also includes grades from other producers including Borealis, Ineos, Sabic and Lyondell Basell.


Power boost A steam power plant in Finland, operated by


Porvoon Energia, has replaced corroded steel pipes with a system that uses PE100-RC from Agru. The pipes are used to transport seawater, which is used to cool the plant. However, seawater is known to corrode metal pipes very quickly. In this case, the existing steel pipes had only been in place for four years. “A large part of the pipelines currently in


operation for seawater or saltwater applications are generally made of high-quality stainless steel, galvanised steel or cast iron,” said Agru. “These materials are widely referred to as ‘saltwater resistant’, but are subject to corrosion over time, which inevitably leads to high maintenance costs and even plant failure or downtime.” For some time, there has been a move towards using plastics in this type of application. Especially under seawater conditions, the service life of thermoplastics is much longer, due to its corrosion


32 PIPE & PROFILE EXTRUSION | April 2021


resistance. Also, the smooth surface of plastic pipe – such as that made from PE 100-RC – stops particles from sticking to it, which means that hardly any deposits are formed. After detailed consideration, the steel pipe was


replaced with PE 100-RC pipes and fittings. The necessary temperature and pressure conditions, including calculated safety margins, are met using an SDR 11 (PN 16) system. In addition, easy installation and low material costs helped to influence the choice. The planning and laying of the new Agru PE 100-RC pipeline was carried out by Finnish company Atolli. Heating coil fittings were used for welding the pipeline sections. The installation was carried out on schedule within a few working days and the power plant was put back into operation, said Agru.


Carbon effect Polymer researchers in Iran have assessed the effect of carbon black on the long-term mechanical performance of PE100 pipe. The researchers, from the department of materi- als science and engineering at Sharif University of Technology in Tehran, used two types of carbon black masterbatch – in an HDPE or LDPE carrier – to make black compounds using three different PE100 resins. In the processing temperature range, no immiscibility was seen between PE100 resin and either the HDPE or LDPE carrier. The resins had different degrees of short chain


branching (SCB), which caused them to behave differently in microstructural development and long-term creep behaviour.


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IMAGE: AGRU


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