Laying method in water

For the reha­bil­i­ta­tion of a drink­ing water pipeline in the dis­trict of Aalen, 200 km north-east of Munich, Ger­many, the DEKOTEC GmbH pro­tects weld seams from cor­ro­sion very quick­ly and effi­cient­ly using a new lay­ing method that floats in water.

For this method, the pipeline was first laid in the water: Just ten min­utes after apply­ing the BUTYLEN-AS50 tape sys­tem to the weld seam, the pipe was pushed into a tun­nel flood­ed with water. The pipeline was then drained four months lat­er. This is impres­sive as pipelines are nor­mal­ly not imme­di­ate­ly and per­ma­nent­ly exposed to cor­ro­sive media. The test results pro­vid­ed by the “Ver­band der Fer­n­wasserver­sorgung” (Remote Water Sup­ply Asso­ci­a­tion) prove: The stan­dard require­ments of DIN EN 12068 for a high-qual­i­ty pro­tec­tion of the weld seams are satisfied.

Direct flood­ing and extend­ed oper­a­tion in water are major chal­lenges for field joint appli­ca­tions. This unprece­dent­ed method shows: The three-ply BUTYLEN tapes fuse togeth­er very rapid­ly. A dif­fu­sion-resis­tant pro­tec­tive hose is quick­ly gen­er­at­ed, with reli­able per­for­mance even when per­ma­nent­ly exposed to flu­ids. The sin­gle-tape sys­tem was applied in at least a three-lay­er wrap­ping using the engine-dri­ven DEKOMAT^®-11 appli­ca­tion device.

The drink­ing water pipeline is one of the region’s main arter­ies. One of the two steel pipelines, with a nom­i­nal diam­e­ter of DN 1200, was restored for long-term use. Water flows through two par­al­lel tun­nels over almost two kilo­me­tres at 1,800 litres per sec­ond. The con­struc­tion mea­sure is expect­ed to be com­plet­ed in the spring of 2019.