18th Century Building Meets 21st Century Coating Technology

The rehabilitation of the drains in the historic Barthels Hof in Leipzig was the last part of extensive renovation work on and in the building complex. The in-house rehabilitation ran from September 2020 and into 2021.

"Not a single pipe is left out in Barthels Hof - from the DN40 shower pipe to the DN200 main pipe. For the smallest pipes from DN40 to DN100 we chose the Picote Brush Coating™️ System." - Thomas Miller, Managing Director of Pipe Bull GmbH.

A different circumstance in this project was the difficult access to the cross-storey ducts. These were concreted on three sides and partially masonry on one side. In addition, the shafts between the individual floors were open, so that in the case of using an open construction method, accessible levels would have to be built in.

The total length of the pipeline to be rehabilitated amounted to an impressive 1.2 km.

The many bends in the pipe run, rather common in Germany, posed another challenge.

“Sometimes we found six to seven 90-degree bends in the DN50 pipes over a length of only two meters,” Miller described the situation in Barthels Hof, “and the DN100 pipes did not run straight from top to bottom, but had five to six 90-degree bends at around 40 meters. Good preparation and a lot of skill were required.”

The numerous and often unexpected changes in dimensions did not make the work any easier either. In recent years, the Barthels Hof has had to contend with water damage. A TV inspection revealed the extent: The installed SML pipes were extremely damaged and showed bursts, cracks and severe corrosion. The damage patterns also included cracks several centimeters long and even pipe dissolution.

The Picote Brush Coating™️ System was used in pipes with the smallest diameters from DN40 to DN100 where CIPP lining was not possible. The system applies a specially formulated 100% Solids Epoxy Resin through a hose and rotating brushes attached to it in the pipe. The hose is pushed into the pipe in flow direction.

When moving backwards, two to three brushes distribute the resin evenly on the pipe wall. The brushes must always be larger than the inner pipe dimension, so that the resin hits every centimetre of the inner pipe wall. The extremely flexible Picote Miller shafts made navigation of the multiple bends easy, even inside the very small pipes in this project. The coating pump in combination with the Smart Mixer 2.0, fitting on the same Miller used for cleaning and preparing the pipes before coating made the procedure mess-free and efficient.

The use of cameras during the coating and the dual-colour cartridge system allowed to visually verify any spots that may have been missed.

In the case of an in-house renovation, the residents' acceptance of the measure and thus their willingness to cooperate are factors that should not be underestimated. After all, the company works in very sensitive areas.

Therefore, prior to and during the renovation, great importance was attached to communication with the tenants and apartment owners.

Another success factor was good time management, ensured by the very short installation and curing times of the Picote Brush Coating™️ process. This made it possible to keep the inconvenience for the residents very short.