TPI November 2020

Business & market news

Trend towards PE pressure pipe systems By Michael Ritz

Pressure pipe systems made of polyethylene are being used in local gas and water supply systems worldwide with a growing market share. This trend, especially with regard to PE pressure pipes with ever larger nominal pipe sizes, is far from over. This is an impressive success story, especially in view of the fact that today’s HDPE pipe quality was only developed 65 years ago. Historically, the development of PE pipes began as early as 1933 with the development of the low-density PE raw material: LDPE, which was produced using the so-called high-pressure process. From today’s perspective, not only was the process uneconomical, but the properties of the PE produced in this way were by no means comparable with today’s PE pressure pipe quality. 20 years later, in 1953, the production of a high-density Polyethylene, HDPE, was successful. This technology, developed by Karl Ziegler and Giulio Natta, enabled polymerisationusingthemoreeconomical and versatile low-pressure process. As early as 1954, the Hoechst company in Frankfurt (today LyondellBasell) started the production of raw materials and PE pressure pipes. Hoechst worked on a broad front to market the new material. Initial applications were found, long-term internal pressure tests were initiated and scientific material studies were carried out to support market demand for applications. In the post- Sung Won Steel Co Ltd, Korea, has announced that it has received an API 5L licence (5L-1174) and has started production, shipping pipe to the USA market. Sungwon Steel USA currently holding inventory in Houston, Texas and California. Manufacturing HFW ERW linepipe and standard pipe, from 2" through 8" ODs, up to X52 PSL-1 grade, the company is a heavy wall ERW pipe manufacturer, able to produce standard wall thicknesses up through the heaviest

war years in the Ruhr area, gas suppliers were looking for an alternative to the grey cast iron standard of the time, as serious failures repeatedly occurred due to ground subsidence and brittle pipes. Initial application tests showed that the welded, elastic PE pressure pipe systems behaved as theoretically expected and did not suffer any damage even in places where soil movements caused failure with the old market standard. These safety advantages of PE pressure pipe systems were decisive for their rapid acceptance by the utilities and subsequently in the gas industry. One of the decisive factors for the rapid spread of the material in pipeline construction was the array of economic advantages of the new type of pipe. The laying of PE pipes of 100 to 1,000m in length, which were installed on-site in the pipe trench as coils or drums, was also groundbreaking. This resulted in fewer connection points and, in addition to the considerable cost savings, in increased system security. Unlike other materials, polyethylene is corrosion-free without restriction, which over time has led to increasingly versatile applications, even for larger nominal pipe sizes. A leap in development that went hand in hand with larger diameters is represented by applications in which almost endlessly long PE pressure pipes were produced directly on the coast. The pipes extruded into the sea were towed to their destination floating

behind ships, for example to connect an island with the mainland. The PE-100 “Peace Water Pipeline” project, an 80km-long DN 1500 pressure pipeline from Turkey to Cyprus, floating freely across the Mediterranean and is unparalleled in the world. The trend towards larger pipe diameters is favoured by the need to transport drinking water, sometimes over long distances. In addition, ever larger industrial plants are being built directly next to the sea in order to be able to manufacture more economically. The production facilities are cooled with sea water. PE is the preferred pipe material for large pressure pipe systems not only because of its corrosion resistance. Using PE also results in an increase of both the pipe diameters and the diameters of the necessary pipe connecting parts. The wall thickness of the pressure pipelines results in the achievable, required operating pressures, whereby it is particularly important that the fittings with the same connection dimensions do not restrict the load-bearing capacity of the piping systems – ie that they are fully pressure-resistant. The production of stable fittings, which includes the manufacturing of fully functional flanges, is the unique selling point of the Reinert-Ritz company in Nordhorn in Lower Saxony.

Reinert-Ritz GmbH www.reinert-ritz.de Sung Won Steel begins ERW pipe production

Steel produce ‘quad stencil’ – API 5L GrB/X42 / ASTM A53GrB / ASME SA53GrB and ‘triple stencil’ – API 5L X52 PSL-1 / ASTM A53GrB / ASME SA53GrB as often required by the North American market and equipment is in place to manufacture according to PSL-2 requirements, and the company expects API to recertify the mill accordingly as travel restrictions resulting from COVID-19 are gradually lifted.

wall thicknesses such as Sch120, 140, 160 and XXH – wall thicknesses that have traditionally only been fabricated by seamless manufacturers. Sung Won

Sung Won Steel Co Ltd www.sungwongroup.co.kr

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TUBE PRODUCTS INTERNATIONAL November 2020

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