TPi September 2016

products & developments 20 years of surface protection for steel pipes

GmbH. A special testing device was developed to determine the mechanical level protection. The results showed that the protection of a steel pipe coated with the

The introduction of GRP coating for steel pipes 20 years ago, marketed as the BWB system, was a success story for BKP Berolina. Since then, more than 110,000m of gas pipes (DN 100 to DN 1,400) have been coated with this special and highly resistant GRP coating. The BWB system contains resin- impregnated glass fibres tangentially and axially wound on the PE coated steel pipe. Meanwhile an environmentally friendly and styrene-free resin is cured by using UV-light. The coating protects the steel pipes from being damaged by obstacles in the soil when being installed by horizontal drilling or similar methods that might cause corrosion. The on-site protection of welded joints is applied by attaching glass fibre mats combined with resin and cured by UV-light. The BWB system is not sensitive to the pulling direction, giving the contractor more flexibility when putting the pipeline together, and avoiding mistakes on-site. In the case of stuck drillings, pulling back the pipeline is still an option as far as soil and equipment conditions allow it.

DN 1,200 casing tube (black), and BWB-coated steel pipe (green) with GRP spacer (brown)

BWB system is three times better than a polypropylene coating and eight times better than a polyethylene coating. BKP Berolina replaced the formerly used styrenated resin with an environmentally friendly and styrene-free resin. For special applications where the pipeline is winched into an existing host pipe, in 2011 the company developed additional GRP spacers already applied with the BWB coating. The advantages of these 50mm-thick spacers were demonstrated during the exchanging of a gas pipeline near Schlüchtern, Germany, last summer. On a section of the MIDAL (Mitte- Deutschland Anbindungs-Leitung) – a connecting gas pipeline in the centre of Germany – some divergences in the galvanic protection had been determined through routine monitoring.

In 1995, the first test was performed in cooperation with the former Wingas

The target pit, close to a highway ramp

The PE-spacer rings had caused damage in the PE-coating of the existing pipeline. The affected section had to be removed and replaced by DN 800 BWB system-coated pipes with additional GRP spacers. To winch the 90m-long pipe section into a DN 1,200 casing tube, a 40mm-thick steel rope was pulled by an 80-ton winch through a 45° deviation. Michael Muth, manager at Gascade Gastransport GmbH, commented, “The BWB system combined with the factory-installed spacers withstands any situation and proved its reliability by 100 per cent.”

Holding the 90m-long pipe section in the right position

BKP Berolina Polyester GmbH & Co KG – Germany

info@bkp-berolina.de www.bkp-berolina.de

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Tube Products International September 2016

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