Realp II power station Lot 2; pressure pipeline

Project description:

In the context of the Realp II new construction project, the Ursern electric power station commissioned Kelag Systems AG to deliver and assemble the steel pressure pipeline for Lot 2.

Scope of work:

  • Engineering, delivery and assembly of the steel pressure pipeline
  • Engineering, delivery and assembly of the Y-pipe
  • 2 x expansion DN 1000 PN 16, executed as access pipe
  • 3 x manhole DN 800 PN 16
  • 1 x insulation joint DN 1100 PN 16, overall length 1100 mm

Technical data:

Steel pressure pipe:60 m, elevated assembly in steep slope
Steel pressure pipe:396 m buried assembly
Diameter:DN 1100 (culvert: DN 1400)
Wall thickness:10 mm
Pressure:Max. 16 bar
Weight:104 tons
Material:S355 J2+N

Buried corrosion protection: Exterior PE with fibre cement encasing, interior 2-component epoxy coating


  • 100 % UT, longitudinal and round seams (in-house)
  • 100 % RT, crossings (in-house)
  • 100 % UT, round seams (on-site)
  • 10 % RT, round seams (on-site)
  • Pressure tests

Special construction conditions:

  • Assembly in alpine area, very steep terrain
  • Culvert assembly in November/December in wintry conditions
  • Construction year(s) 2016–2017
  • Owner Elektrizitätswerk Ursern, 6490 Andermatt, Switzerland