Sheltered waters - Speedy installation of a cast iron drinking water pipe ND 300 using HDD
Shortly before the beginning of the summer season in 2017 in the town Barth in Germany, the grey cast iron transport pipe line built in 1932 was damaged yet again. Ultimately, it was the growing fear that the pipe might burst which forced the water and sewage authority, Boddenland GmbH, to act.Repairing the damaged area under these circumstances was out of the question. In accord with the assessment of the situation by TIAS Tiesler, the following solution to the problem was put forward to the utility company: complete new pipe installation for the entire damaged section using the HDD method.
The town of Barth lies in the north-east of Germany and attracts many holidaymakers from all over Germany and Europe. Barth lies on the southern shore of the "Barther Bodden" (Barth Lagoon). With its numerous tourist attractions and its close proximity to the Baltic resort of Zingst, it has become an important area for the federal state of Mecklenburg-Western Pomerania.
Shortly before the beginning of the summer season in 2017, the grey cast iron transport pipe line built in 1932 was damaged yet again. Damage to this pipe line was a frequent occurrence as environmental influences, corrosion and age-related wear could not be kept at bay any longer. It was posing an increasing hazard for losing supply reliability. Ultimately, it was the growing fear that the pipe might burst which forced the water and sewage authority, Boddenland GmbH, to act. However, conventional means of repair proved to be problematic from both technological and environmental aspects, since near-surface groundwater levels and the swamp-like soil conditions in some places would have made the building project very difficult – especially because the existing drinking water pipe line in an unspoilt Flora-Fauna-Habitat showed signs of damage.
Knowing about their outstanding experience in this field of work, the utility company turned to the TIAS Tiesler GmbH for help. The regionally operating construction company was asked to use its experience in handling projects under difficult general conditions to find and subsequently implement a solution. The initial apprehension proved to be justified and a serious problem was found after the location of damage. The pumps that had already been installed on site to lower the groundwater level were by no means powerful enough to produce the force required to down it sufficiently. Repairing the damaged area under these circumstances was out of the question. This confronted the responsible decision-makers with enormous problems because the drinking water pipe line was also the main water supply line for the Baltic resort of Zingst. But a reliable water supply was vital, especially on account of the expected influx of visitors in the holiday season.
In accord with the assessment of the situation by TIAS Tiesler, the following solution to the problem was put forward to the utility company: complete new pipe installation for the entire damaged section using the HDD method. The suggestion was accepted as the optimal solution to the problem. Immediately after being commissioned, TIAS Tiesler contacted its long-term business partner, Beermann Bohrtechnik GmbH. Both companies have worked together for many years in an atmosphere of mutual trust. They can look back on a successful collaboration covering more than 20 kilometres of drilled supply pipe lines, mainly made of cast iron, using the HDD method. This company is reputed to be a specialist in handling difficult projects with the HDD method and was therefore asked to develop a bore concept for carrying out the job.
The affected stretch which required new pipe installation was split into two sections (270 and 340 metres). An existing paved forest track was the starting point for the two sections in need of new pipe work. Since the new pipes were installed in the protective strip close to the existing pipeline, it was even possible to provide water within the immediate area surrounding the launch pit with the help of a tapping clamp. Therefore the impact on the environment was reduced considerably in a sustainable manner.
In parallel, the customer carried out a survey of the ground conditions, since it was necessary to determine the local geology and draw conclusions relating to the drilling work and the composition of the drilling fluid thereof. Based on these jointly formulated general conditions, planning started immediately with the aim of ensuring a quick and continuous connection of the drinking water pipe line. There was no more time to lose, so drilling began as soon as the job was allocated.
Both sections of the size 300 ductile cast iron drinking water pipe line were completed using the HDD method in only eleven working days and without delay.
The customer was fully satisfied with both the completion of the work, well ahead of the schedule, and the quality of the services. This goes to show that good cooperation between all the project participants always pays off, especially in such cases.