- The project in Aarhus, Denmark, involved replacing an old concrete water tank with six 3000mm diameter plastic pipe segments.
- The new system uses BorSafe™ HE3490-LS-H and HE3493-LS-H, both PE100-RC-classified materials.
- The pipes are expected to last at least 100 years, reducing environmental impact and maintenance needs.
- The dual-wall design and tilted layout enhance security and ease of maintenance.
Project Overview
An aging underground concrete water tank in Aarhus, Denmark, was replaced with a more reliable solution using Borealis polyethylene (PE) materials. Krah Pipes OÜ manufactured six segments of giant plastic pipe, each 3000mm in diameter, to replace the old structure, storing 2000m³ of drinking water.
Challenges of Aging Infrastructure
The old concrete tank required divers for inspection and cleaning every five years, with cracks and leaks often going unnoticed until urgent repairs were needed. The new system reduces these risks with a pressurized dual-wall design ensuring tightness and security, and a tilted layout allowing sediment to wash away naturally, minimizing manual cleaning. Maintenance is simplified with pressure monitoring, eliminating the need for deep diving inspections.
Material and Design Advantages
The pipes are made using two advanced PE grades based on Borstar® polymerization technology. The main pipe body is constructed from BorSafe™ HE3490-LS-H, a high-density PE100-RC-classified compound offering exceptional resistance to slow crack growth and rapid crack propagation. The yellow inner layer, made of BorSafe™ HE3493-LS-H, adds functionality by facilitating visual inspections with its light color.
Sustainability and Longevity
In addition to improving efficiency, the pipes support sustainability with an expected service life of at least 100 years, reducing material use and the environmental impact of replacement. This approach has proven effective, with another old tank in Aarhus already replaced using the same concept and materials, demonstrating a scalable solution for modern water systems.
