After several pipes have been welded each joint is grit blasted inside and out. They are then painted with two coats of epoxy paint. This is checked with an electrometer to ensure it is the right thickness (in microns).

The 85t excavator and man grit blasting help to give some scale.

The pipes are upto 1.8m diameter and 12m long. Each joint is welded twice, once inside and the other outside. This is then pressure checked with Nitrogen (as it is an inert gas).

You can see the pipeline stretches some distance as you can see.