Engineering Insights
Why surface preparation decides the life of a pipeline coating
Decoating and sand blasting are slow, noisy and easy to rush. Here is why we never do — and the checks we run before a single litre of coating goes on.
A pipeline coating is only as good as the steel underneath it. Mill scale, old coating residue, salts and moisture all shorten the life of a new system, sometimes to a fraction of its design life.
Decoating the old system
On river-crossing and onshore sections we strip failed coatings mechanically before blasting. Rushing this step leaves islands of old material that the new coating cannot bond to.
Blasting to profile
Abrasive blasting cleans the steel and gives it a surface profile — a pattern of tiny peaks and valleys the primer keys into. We check cleanliness and profile against the specification before releasing the surface for coating.
Weather windows
In the Delta, humidity is the enemy. Blasted steel can flash-rust within hours, so blasting and priming are scheduled together and stopped when conditions fall outside the coating manufacturer’s limits.