To overcome the challenges posed by the installation of pipe, a new breed of extremely tough, high stress crack resistant (HSCR) PE100 polyethylene materials have been launched by Borealis in Europe and Borouge in the Middle East and Asia.

These PE100 materials, typified by BorSafe HE3490-LS-H, provide a much higher resistance to crack growth than standard PE100 materials, making them ideal for tough laying conditions. This is achieved by selecting the optimum co-monomer and polymerisation conditions for the production of the polymer. This creates a polyethylene material with an extremely tough structure that inhibits crack growth from gouges and scores on the surface or due to point loads from rocks and debris in the surrounding soil.

For example, in notched pipe tests the performance is over 20 times the 500 hour required for standard PE100 pipes, which makes it ideal for manufacturing pipes for insertion replacement, horizontal directional drilling (HDD) or laying in difficult soil conditions.

This new material was successfully used for the provision of a new water supply pipeline to the joint China – Singapore Eco City in Tianjin. The Tianjin TEDA water company identified a new source of water, but it lay on the far side of the Ji Canal. Whilst the company was keen to use a PE100 pipeline, it was concerned about any surface damage to the pipe caused by the HDD installation process under the canal. Together with its customer, Cangzhou Mingzhu Plastic Co., Borouge demonstrated the benefits of the new HSCR PE100 material to allay the concerns of the water engineers.

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The section of the 4.5 km, 800 mm diameter SDR 17 pipeline installed under the canal was subsequently manufactured using the BorSafe HE3490-LS-H material and the pipeline installation was successfully completed in October 2009.

The new high stress crack resistant material can also be used to provide additional security in industrial applications as demonstrated in the internal lining of water injection pipelines for the Kuwait Oil Company (KOC) in the Middle East. These steel pipelines were heavily corroded and while replacement would be costly, the environmental risk from leakage was unacceptable. Therefore the oil company opted to reline the pipes with a ‘close fit’ polyethylene pipe manufactured from BorSafe HE3490-LS-H using the swagelining technique.

The relining project was undertaken by Kuwait International Advanced Industries and Anti-corrosion Protection Systems and was successfully completed in October 2010, providing KOC with a cost-effective, long term solution, which won’t suffer from the same internal corrosion problems.

Utilising No-Dig pipe laying techniques, wherever possible, helps to reduce project costs and the disruption to the local community. Now using these HSCR PE100 materials, the pipeline engineers can be reassured that the pipes can withstand this tough treatment without any loss of operational lifetime.