In Gothenburg, a new drinking water pipe was inserted into contaminated soil under the river Göta älv using the HDD method. For safety reasons, the customer requested that inspection of the pipe both prior to insertion and afterwards should be possible. The implementation of this request involved the SLA^® Barrier Pipe system.

The island of Hisingen, the fifth-largest island of Sweden, is the site of the major part of the Gothenburg harbour as well as of some oil refineries. The construction of a new water supply pipeline from the centre of Gothenburg to the island of Hisingen involved creating an underpass over a total length of approx. 560 m under the river Göta älv. The HDD drilling works were executed by BAB Rörtryckning AB. To underpass Göta älv by HDD drilling was complex, because of complicated geological conditions with contaminated mud and a drilling with a depth of more than 30 meters.

Therefore the pipe system of choice was the SLA^® Barrier Pipe system featuring dimensions of 630 x 70.3 mm SDR 9. The SLA^® Barrier Pipe system reliably prevents any permeation by hazardous substances. Its metallic permeation barrier allows for permanent protection of sensitive media and their environment. In addition, its electrical properties also provide optional
pipeline detection and inspection for intactness before and after installation. Both the inner pipe and the barrier layer are reliably protected by an additive protective layer, making the system suitable for trenchless installation.

The pipes were connected via butt welding. Prior to insertion, the integrity of the pipe string to be inserted was examined by means of a puncture test using a highvoltage tester. Only if the test result was found to be positive, the insertion of the pipe string was initiated. Following smooth completion of the drilling, the pipe string was tested again: After insertion, too, the integrity of the pipeline was established and approved by the site manager. Both the pressure pipe and the permeation barrier were found to be intact.

Project data
Project description:	New water supply line from the centre of Gothenburg to the island of Hisingen
Challenges:	Installation in contaminated soil, integration testing required before and after the installation
Solution:	Permeation-tight pipe system made of polyethylene providing optional inspection for integrity
Installation:	Horizontal directional drilling
Pipe system:	SLA® Barrier Pipe System OD 630 mm SDR 9 560 m
Parties involved in the project:	Installation: BAB Rörtryckning AB, Hisings backa, Schweden

Contact

Peter Ziegler
Tel: +45 29 660 899
peter.ziegler@egeplast.de

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