CWC Removal

Concrete Weight Coat (CWC) Removal from a Steel Pipeline

This is an established and well proven technique for removing short sections of Concrete Weight Coat (CWC) from a steel pipeline for:

1. Pipe repairs, investigation or tie in of another pipe. This may be onshore or in a habitat.
2. Pipe “cut to length” whether on a pipelay vessel or onshore.

We team up with another specialist who cuts the slots in the CWC and ThinJack Ltd removes the Concrete Weight Coat, as shown in photographs A to E below.

For subsea pipelines, one of ThinJack Ltd's (non diving) technicians works with those who are inside the subsea habitat. They install and operate the ThinJack system, and our technician supports you with knowledge and guidance.

Summary

Picture 14

A

Tracks are cut in the concrete jacket: one track axially, along the crown of the pipe at 12 o’clock, and up to two tracks radially.

Picture 15 copy

B

One of several curved ThinJacks inserted into a radial track before inflation.

Picture 16

C

The same ThinJack inflated with 400 bar of pressure, with a stroke of around 10 to 12 mm, forcing the CWC in an along pipe direction with a force of around 200 tonnes.

Picture 17

D

To finish: An axial or straight ThinJack inflates, pushing the 12 o’clock crown of the pipe in a radial direction.

Picture 18

E

Leaving the CWC exfoliated, or peeled off, below. The adhesive mastic covers the steel pipe.