Bayernwerk Project Report: Deployment under High Pressure

To increase capacity in its high-pressure network, Bayernwerk Netz GmbH used the HexelOne® SLM gas pipe. The new high-pressure pipeline transports gas with a pressure rating of 16 bar. By using trenchless techniques, civil engineering costs could be kept low and interventions in the landscape reduced to a minimum.

High-Pressure Transmission Pipeline with a Pressure Rating of 16 bar – HexelOne® SLM

As part of this construction project, various companies were also integrated into the existing gas network, including a mega-greenhouse. In the future, gas with a pressure rating of 16 bar will be transported to consumers via the high-pressure transmission pipeline. Due to the required operating pressures, the HexelOne® SLM gas pipe with dimensions 160 x 14.6 mm was chosen. The pipeline routing and local conditions required the use of various Installation technologies. By using trenchless techniques as needed, the construction time could also be significantly reduced compared to open-trench Installation. Peter Hößl from Bayernwerk Netz GmbH: “By using the HexelOne® system, we were able to reduce the total costs of the construction project and halve the construction time compared to using other materials.” Karl Krumpholz Rohrbau GmbH was commissioned with the overall civil engineering and pipeline construction work. The plowing and milling work was awarded to selected subcontractors.

Preißinger Bau GmbH & Co. KG installed approximately 2,100 m of pipeline using the plow-in Installation method, with a daily output of about 1,000 m. Fräsen Schmid GmbH from Neumarkt took over the milling-in of 5,500 m of pipe material. The route passed through quite challenging terrain along roads and through wooded and rocky areas. 600 m were installed using the horizontal directional drilling (HDD) method by Richter-Bau GmbH & Co. KG from Altenkunstadt. The remaining part of the total approx. 9,000 m of HexelOne® SLM pipeline was installed using open-trench construction. The earthworks and Installation work were carried out by Krumpholz GmbH from Kronach.

Short Construction Time Due to Long Coils

Due to the long delivery lengths – 100 m coils – the number of connection points was immensely reduced compared to other materials (approx. 100 connections compared to more than 750 necessary connections for steel). Permitted connection techniques for HexelOne ® SLM pipes include welding using combination welding and connection using press fittings. On the long sections that were installed using plowing, milling, or horizontal directional drilling (HDD) methods, combination welding was primarily used, a combination of butt and electrofusion welding. Press fittings were used in the starting and target pits of the HDD operations to connect the individually pulled-in pipe strings. The construction project was intensively supported by the technical egeplast field service throughout the entire construction period. The pipeline was successfully commissioned in September 2020 after a five-month construction period, to the satisfaction of all involved parties. Meanwhile, Bayernwerk has carried out over half a dozen construction projects with more than 30 km of HexelOne® SLM high-pressure pipe system.