Protection · Pipelines
Pipe Coating
The external layer that isolates buried steel pipe from the soil, applied at the mill and completed at the girth welds in the field.
What it does
It is the first barrier against external corrosion and cathodic protection covers its gaps. Fusion bonded epoxy is the most widely used coating today; older tape and coal tar coatings tend to disbond and let water reach the steel.
Basics
| Most used today | Fusion bonded epoxy (FBE) |
| Older types | Tape wraps and coal tar |
| Applied | At the mill, plus field joints at girth welds |
| Paired with | Cathodic protection |
Common failures
- Disbonded coating that shields the steel from cathodic protection current
Troubleshooting
- Symptom
- Cathodic protection current demand keeps rising
- Likely cause
- Coating degrading
- What to check
- Run a coating survey and plan repairs at the worst spots