Contour Takes on External Corrosion at a Chemicals Factory

Pipe Details

  • 25-mm (1-inch) diameter.
  • API 5L Grade B steel.
  • 4 bar (58 psi) design pressure.
  • 40° C to -40 °C (104° F to -40° F) design temperature.
  • 3.9 mm (0.15 inch) original wall thickness.
  • 1 mm (0.04 inch). remaining wall thickness.
  • External corrosion.
  • Ammonia pipework


  • A Contour repair was installed on a 1-inch (25-mm) diameter API 5L Grade B steel pipeline with 3.9-mm (0.15-inch) wall thickness that had eroded to 1 mm (0.04 inch).
  • A trained technician carried out the repair in 3 hours.

Inspections at a chemicals factory revealed significant corrosion on a 25-mm (1-inch) diameter API 5L Grade B steel pipeline with 3.9-mm (0.15-inch) wall thickness designed for 4 bar (58 psi) pressure and temperatures of 40° C to -40 °C (104° F to -40° F) that was transporting ammonia. When the corrosion was identified, the wall thickness had eroded to 1 mm (0.04 inch).

Because the factory owner did not want to take the line out of service while repairs were being made, it was necessary to choose a repair method that did not require hot work. The decision was to use Clock Spring Contour to address the severe corrosion.

The surface of the pipe was prepared using hand tools followed by solvent to remove dust, grease and any oil deposits. A trained and certified installer completed the repair within 3 hours.  The line was in normal service throughout the repair installation.

There are nearly 3,000 trained Clock Spring installers around the world who are qualified to provide repairs with Clock Spring products. Clock Spring regularly offers training classes for installers and can custom design training for individual company needs.

External Corrosion on Steel Pipeline
External Corrosion
Completed Repair on Steel Pipeline
Completed Repair