The extensive perforations in the sectional glass fused steel tank had been highlighted as an environmental concern by our Water Industry client. A tank reline was proposed to resolve the problem.
Due to the tanks sectional nature a flexible yet chemical resistant tank lining solution is required. These tanks when emptied and filled can exert as much as 14 Tons of lateral force on the panel joints – making brittle lining such as fiber glass tank lining unsuitable. We proposed the application of Corrolastic UB polyurea manufactured for us by SPI. This material is highly flexible and can elongate over 300%, whilst also being high tensile and chemical resistant.
Following drain down and cleaning all surfaces were prepared by method of abrasive blasting to expose fresh silica in the glass enamel for the tank lining to adhere to. A minimum surface profile of 75 microns was achieved which was tested using surface profile needle gauges. Old sealant was removed using scrapers where required.
Priming the exposed steel with Corroless EPF Rust Stabilising Epoxy Primer
Once thoroughly cleaned to ensure excellent adhesion of the new tank lining any exposed steel was primed using Corroless EPF rust stabilising epoxy primer to a thickness of 200 microns.
As part of our standard quality assurance a soluble salt test was conducted at various locations throughout the tank.
Perforations in the tank structure were plated using galvanized steel bonded in position using SPI Ralithane polyurethane jointing compound.
Glass fused steel can be a difficult surface to adhere. Fortunately SPI have available for our use their AE4 adhesion promoter which allows the polyurea tank lining to adhere to free silica in the glass enamel.
Applying the SPI Corrolastic UB
SPI Corrolastic UB was spray applied to a thickness of 2mm. The polyurea tank lining was then tested for porosity using a DC holiday spark tester. Where pin holes or defects were found these were marked and repaired.
Because Corrolastic UB contains SPI’s ultrabond molecule no additional priming or preparation was required to make these repairs, as it would for conventional polyurea tank linings due to their short over coating windows.
We provided the client with a 10 year warranty on these works.