Broadband expansion in the Federal Republic of Germany is progressing. In many places in the country, there are construction sites where civil engineering companies are laying the necessary empty conduits for the creation of high-performance broadband networks, financed in part by the Federal Broadband Funding Programme of the Federal Ministry of Transport and Digital Infrastructure (BMVI). Various installation methods are used, which are selected according to the conditions in the respective district. Possible construction methods for creating a broadband infrastructure include ploughing and the use of a trencher, the directional drilling method and the trenching method. The use of existing pipe infrastructures is also an option for laying broadband cables, subject to appropriate preliminary testing.
For broadband expansion, the municipalities, cities, districts and local authorities select the appropriate methods according to the respective local conditions. The selection criteria for the installation methods relate not only to the nature of the ground in which civil engineering work is required, but also to the possible restrictions imposed by the construction sites, the costs or the presence of existing pipe network infrastructures. As a rule, various methods are combined in the expansion areas in order to ensure a comprehensive broadband infrastructure.
The trenching method is an innovative installation method, as the empty conduits can be laid directly in the asphalt over a relatively long distance at a shallow depth. A kerb along the edge of the asphalt serves as a support so that the duct, which is milled into the asphalt, cannot break away. The empty conduits are well protected from the weather by the asphalt surface.
The plowing-in method and the use of a trench cutter make it possible to lay cables over a long distance in a short time. In this method, the construction machinery digs a cable trench into the ground, usually at the edge of farmland or parallel to asphalt roads in the unpaved surface. The empty conduits for the cables are then laid at a depth of at least 60 centimetres.
Some districts, such as Fulda in Hesse, Rottweil in Baden-Württemberg and Uelzen in Lower Saxony, which receive funding from the federal broadband funding programme, have opted to use the directional drilling method. In this method, a hole is drilled through the ground in a section approximately 100 to 150 meters long. Depending on the soil conditions, the resulting drill channel can become unstable, so a drilling emulsion consisting mainly of bentonite and water is added during the drilling process to ensure the stability of the drill channel. The drill is then used to pull an empty pipe through the drill channel. Costs can be saved due to the reduced excavation of the ground and the resulting elimination of construction site distances.
The directional drilling method is suitable for regions where the ground surface should remain untouched or where construction sites can only take up a small amount of space. These include, for example, protected areas or terrain that is difficult to access with considerable differences in height.
In the district of Fulda, this installation method is suitable for the UNESCO Rhön Biosphere Reserve. The area extends across the federal states of Hesse, Thuringia and Bavaria. The local farms and businesses as well as the tourism industry work together to preserve and promote the diversity of the habitat in the Rhön. To this end, the area has been divided into various zones in which more or less strict conditions apply to farming. Nature conservation plays an important role in the development of the region, which is to be preserved in the long term as a habitat for humans and animals and sells sustainably produced products with its own seal of quality.
For the broadband expansion in the district of Fulda, this meant minimizing the impact on nature and the landscape by using the directional drilling method in order to have as little impact as possible on the sensitive biodiversity. During the planning phase, the district was particularly keen to use environmentally friendly and resource-saving techniques for broadband expansion. Therefore, in addition to this method, decommissioned pipe network infrastructures such as old drinking water and wastewater pipes were also used for broadband expansion. This method is rarely used for broadband expansion, as it requires comprehensive and very precise preliminary inspections to determine the location and condition of the decommissioned pipes and ensure their suitability for the cables.
The use of innovative installation methods and particular topological or geographical difficulties in the expansion area are taken into account in the scoring model, which is used in the federal broadband funding programme to evaluate funding applications. As an entrusted promoter for the BMVI, aconium acts as a fiduciary administrator for the federal broadband funding programme as an approval and review authority and must ensure compliance with the relevant procedures in accordance with the Federal Budget Code (BHO) and other regulations.
The scoring is a points system and is used to check all eligible applications for infrastructure funding in the economic viability gap and operator model for their eligibility for funding within a call. The use of innovative installation methods is evaluated positively in the funding application, as these help to minimise expansion and installation costs and make efficient use of funds.
In the information brochure “Installation methods for broadband expansion“, the BMVI’s Digital Networks Working Group describes in detail other installation methods for empty conduits and cables for shallow broadband networks in accordance with Section 68 (2) TKG. In addition to the respective advantages and disadvantages of the installation methods, it also contains information on the applicable guidelines and technical regulations.
Photo above: A mud drill in Fulda.
Photo below: The flush drilling process in Uelzen.
Photo credits: aconium GmbH