Hydrotesting of Storage Tanks with Aluminum Floating Roofs

Crude oil storage tanks often face corrosion problems during the construction phase when hydrostatic testing is performed. Damage to aluminum alloy floating roofs can occur rapidly, with poor hydrotest water quality being suspected of causing localized corrosion. This article presents two case studies along with a benchtop research project. The field failures pointed to microbiologically influenced corrosion (MIC) and chloride-induced corrosion as the primary causes for the damage. The laboratory study concluded that sterile water would be best for use as hydrotest water, which would be impractical to implement onsite. A pragmatic solution would be to install the floating roofs after hydrotesting.