In the middle of Prague’s city center, an old steel pipe was rehabilitated with the egeLiner® technology. Due to the confined space, the high installation speed, and in order to avoid traffic disruptions, there is no economically viable alternative to this rehabilitation method for gas pipes. The Prague gasworks therefore regularly use the egeLiner®.
Project description
Rehabilitation of a historical gas pipeline in Prague’s city center near the riverbank
Challenges
- Tight time frame
- Limited space
- High traffic volume
Solution
Use of the egeLiner® RC on drums for trenchless insertion
Project participants
| Client | Prague Gasworks |
| Location | Prague, city center |
| Planning office | Projektová Kancelár ANY |
| Implementation | Installation: Zepris s.r.o. / Ludwig Pfeiffer
Distribution partner: Gerex Liberec as distribution partner |
| Construction company | Zepris s.r.o. / Ludwig Pfeiffer |
Rehabilitation of a gas pipeline in Prague’s city center
In the course of planned road rehabilitations and the reconstruction of the “Bridge of the Legions” in the city center on the banks of the Vltava in July and August 2020, the DN 500 steel pipe was rehabilitated. The insulation of the old steel pipe no longer met today’s requirements. With the rehabilitation of the gas pipeline, the Prague gasworks are ensuring the future operational and supply security of gas customers. The Prague gasworks have long been one of the most important energy suppliers in the Czech Republic, with the company’s history dating back to 1847. Today, they reliably supply around 420,000 consumers throughout the Czech Republic with gas and electricity. The project was planned by Mr. Ing. Arnost Polak from the engineering office Projektová Kancelář ANY. He has many years of experience.
For operational and supply security
A total of 404 meters of egeLiner® gas pipes made of PE 100-RC, DN 500, SDR 21 were used. The construction site was divided into 6 sections of 30, 82, 51, 67, 81 and 93 meters each. The sections were produced exactly according to the section lengths, wound on drums, delivered to the construction site and pulled directly into the old pipe by the installer on the construction site.
Easy insertion into the old pipe
The investor deliberately selected the egeLiner® as a pre-formed pipe for close-fit lining due to its special advantages, because with this rehabilitation, the existing pipeline continues to be used. The method is a close-fit technology according to EN ISO 11295. The egeLiner® PE 100-RC is resistant to stress cracking and has been used in the gas industry for some time due to the special safety requirements and positive experience. The result of the rehabilitation is a PE 100-RC pipe with the same pressure class as the surrounding steel pipe, which additionally protects the inner PE pipe from possible mechanical damage. The installation was carried out by Zepris s.r.o., a subsidiary of Ludwig Pfeiffer, which specializes in trenchless rehabilitation methods for drinking water, waste water and gas pipelines. Many joint projects with large pipes and in specialist civil engineering have been successfully and professionally carried out with this important partner of egeplast in the Czech Republic by qualified personnel. The egeLiner® system was supplied by Gerex Liberec as the exclusive distribution partner in the Czech Republic.
Good planning and coordination
Construction work began on June 21, 2020, and commissioning took place as early as August 29, 2020. The installation during the main tourist season in the center of Prague went according to plan with only minimal traffic interruptions – thanks to good planning and close coordination between the supplier, the supplier and the construction company. Branislav Ohrablo, construction manager at Zepris s.r.o. with many years of experience in the field of close-fit lining, has preferred to use egeLiner® pipes in recent years. He says: “We appreciate the reliable transport and delivery of the egeLiner® pipes, the packaging in white film and the high-quality fastening on the drums, which enables the drums to be unrolled in several sections. The material is of high quality and behaves ideally in the reverse deformation process. Thank you for the excellent cooperation.”
egeplast
egeLiner®
The pre-shaped egeLiner® is wound onto steel drums, tailored to the length of the section being renovated. This achieves a cross-sectional reduction of up to 40 percent, allowing long construction lengths to be delivered to the site.
Fundamentally, the folded egeLiner® pipe strives to equalize the stresses frozen in its wall and transform back into its round original shape — this is referred to as the reversion process, which causes the return to the original form (“memory effect”). This property makes the close-fit method highly efficient and ensures that, after successful Installation, the egeLiner® adheres closely to the inner wall of the old pipe and can be fully integrated into the existing pipeline network without restriction.
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