Defect Description
Corrosion under insulation (CUI) was identified on the vertical tank shells. This resulted in external corrosion patches and pitting of varying sizes and depths. The defects were classified as Type B and required numerous composite repairs to prevent further deterioration and restore tank wall strength.
Repair method
Metalyte Pipeworks designed a composite patch repair system in line with ISO 24817 and EEMUA-159.
- Defects were faired using Herculyte epoxy resins.
Repairs were applied using Dragon Q-STD composite system, with the number of layers varying
depending on defect dimensions and elevation.
Repairs included minimum overlap and taper in accordance with ISO requirements.
Repairs were finished with UV- and chemical-resistant coating for long-term protection.
Outcome
Repairs provided a 20-year design life as agreed with the client.
Tanks were restored to safe operating condition, mitigating further external corrosion.
Work was carried out under strict QA/QC control, with hardness testing, temperature monitoring, and full documentation provided.
