Greater Supply Security for Industry, Commerce and Homes

The pipeline designated EGL 442 carries natural gas to 26 industrial, commercial and municipal utility customers. It thus provides a secure and reliable supply of energy to numerous commercial enterprises and private households in south-east Thuringia and Saxony.

More efficient, flexible and secure

"By modernizing EGL 442, we are bringing the pipeline into line with the current state of the art," says Ferngas project manager Philipp Egle. "This will also make network operations more flexible and efficient and upgrade the monitoring technology."

To safeguard supply security for the next 50 years, Ferngas Netzgesellschaft has high expectations of the quality of the line pipe material. Operation at up to 84 bar will in future be possible, and the transport of hydrogen is also envisaged.

Five-year installation project

The 125 km network section is a complex system of network nodes, branches, supply stations and consumer connections. Numerous roads, streams and rivers have to be crossed. The installation work has therefore been divided into 20 sections. Work got underway back in 2019 and is scheduled for completion in early 2023.

"We are upgrading the energy infrastructure by using the replaced pipeline to improve the security of supply for decades to come – also with a view to transporting hydrogen."Philipp Egle, project manager Ferngas Netzgesellschaft

Meticulous planning and execution

By establishing bypasses, an uninterrupted supply to all customers is initially ensured while installation work proceeds. The plan then envisages the measurement of the existing pipeline and the marking of the protection and work areas. The old pipes are then exposed, lifted out of the pipe trench and cut to appropriate lengths for transportation. The new pipe is then welded into strings and laid in the same place in the pipe trench. This calls for a total of around 10,000 welds, each of which is individually inspected, and then the entire pipeline section is subjected to a stress test.

Elaborate system of production, processing and logistics

Just as complex as the pipeline itself and its installation was Mannesmann Line Pipe's project and logistics management. Pipes of varying dimensions and wall thicknesses with a wide range of coating variants are required.

For individual sections, for example, this means the punctual delivery of pipes in diameters DN 100, 150, 400 and 500 and various wall thicknesses from 3.6 to 11 mm in grades L290NE and L360NE. Depending on the application and laying method, PE coatings, PE coatings plus FCM-N (fiber cement mortar) coatings or PE coatings plus GRP (glass-reinforced plastic) coatings are supplied. In total, this involves an elaborate system of production, processing and logistics for approx. 7,000 pipes, spread among around 760 truckloads.

No two sections the same

"For us, 20 installation sections unfortunately doesn't mean the same procedure 20 times," says Egle. "Routine hardly ever cuts in on EGL 442." That's because each section has its own topography and tricky maneuvers. Like, for example, a section some 230 m long that had to be laid in the Zeulenroda reservoir. To obtain the necessary installation and assembly clearance, the level of the reservoir first had to be lowered by 5.85 m. "That was particularly challenging in this area in terms of preparation and planning," says Egle. Because not only did the pipe-laying work have to be meticulously prepared, but the needs of tourism and water management also had to be taken into account.

After all preparations had been made, the new pipe string was welded to the matching pipe bends, tested and coated with fiber cement mortar. The string was then laid with the aid of five diggers, which positioned the new pipeline precisely in the right place. This was followed by the connection to the up- and downstream pipeline sections.

"After just one vegetation period, it looks in most places as if we had never been there at all," says Egle summing up. "And that is actually our aim: to establish security of supply that you don't even see. And that for over 50 years."