DN 900 pipeline renovated with multi-liner solution

Situation

A mild steel cement-lined pipeline DN 900 runs underneath a busy street and a highway access and has two opposing bends of 22.5 degree. Rehabilitating the pipeline with dig & replace would have caused road closures for several weeks, affected the environment and residents and thus was not a real option. The only feasible rehabilitation method seemed Primus Line?. Its flexibility allows the Primus Line system to be installed through consecutive bends of up to 45 degree. Even 90 degree bends can be handled, depending on the characteristics of the pipeline. From Primus Line perspective, there were two options for rehabilitating the trunk main:

• Installing one Primus Liner DN 500 PN 16 with an inner diameter of 452 mm would grant the Hunter Water a utilisation of under 25%.
• Installing three Primus Liners DN 450 PN 16 with an inner diameter of 396 mm would grant Hunter Water a utilisation of nearly 60%.

The pipeline section to be rehabilitated was relatively short, just about 140 metres. Moreover, the friction coefficient of the Primus Liner is with a K-factor of 0.028 lower than the friction coefficient of the existing main. The results of Hunter Water’s calculations finally showed that a reduction in diameter would be acceptable. In the end, the utility service supplier decided to rehabilitate the pipeline with the Primus Line 3-in-1 solution to obtain a higher utilisation. Installing three Primus Liners DN 500 was not an option, as the liners could not fully inflate inside a DN 900 host pipe. A minimum inner diameter of 1000 mm or greater would be necessary.

Technical Details

• Material of Host Pipe: mild steel cement-lined
• Transported Fluid: potable water
• Diameter of Host Pipe: DN 900
• Operating Pressure: 12 bar
• Primus Line? System: DN 450 PN 16
• Total Length: three liner of 140 m each
• Number of Sections: 1
• Installation Time: one week

Project Description

The existing pipeline was extended at both ends with a customized reduction piece DN 900 to DN 1600 to create space for the three Primus Line flanges. The reduction as well as the custom-made manifold were designed by Primus Line and produced locally by Hunter Water.

The Primus Liner was transported on three reels to the construction site. These were placed one after the other behind the start pit in line with the run of the pipeline.

Each liner was marked with tape of a different colour to ensure that after insertion, the hoses were at the correct positions at both ends of the pipe. During insertion, the liners were combined to a sort of sandwich on top of each other and fixed with tape to keep their shape.

After insertion, Primus Line installation partner Interflow threaded the liners through a customized manifold and brought them one by one into shape with compressed air.

After the inflation process the six Primus Line connectors could be installed.

The entire installation of the Primus Line? system could be completed within one week. A separate pressure test with 15 bar was conducted for each liner.

Our Services

• Supply of 450 m DN 450 Primus Liner and six terminations fittings PN 16
• Design of the manifold
• Supervising

About Primus Line?

The Primus Line? system is referenced in EN ISO 11295:2017 – classification and information on design and applications of plastics piping systems used for renovation and replacement. The Primus Line? system also complies with the technical standard DVGW VP 643 – flexible textile-reinforced plastic inliner for pipe-relining of gas high pressure pipes. The system consists of a Kevlar?-reinforced liner and specifically developed end fittings. The liner accommodates the operating pressure of the pipe, due to the reinforcement layer and does not bond to the host pipe. An annulus space remains. The liner is seamlessly manufactured at an ISO 9001 certified production plant in Germany and transported to the site on reels. Due to the flexibility of the material, the liner can traverse angles of up to 45 degrees, can be installed in lengths of more than 1,000 m in one pull, and has an installation speed of up to 600 m per hour.

About the Author

Heiko Manzke is Director at Primus Lines Australian subsidiary. Primus Line provides a unique system for the trenchless rehabilitation of pressurized assets. Heiko has been working with utilities, refiners, engineering firms and specialized contractors in Australia, Europe, South America and the Middle East to provide engineered trenchless water main, rising main and gas pipeline rehabilitation solutions. He holds an engineer’s degree and also completed the postgraduate studies "Technical Sales and Distribution" at the University of Applied Science of Deggendorf in Germany.