THE PROBLEM – Feed Hopper Tank Lining
The feed hopper tank lining was suffering from corrosion and erosion as a result of an insufficient protective lining from new. Due to the operating requirements of the plant the tank could not be out of action for more than 48 hours. Another contractor had utilised a polyurea tank lining material on another site but took too long to complete the works and only applied half of the thickness of material which they had specified.
We recommended the application of a high quality pure polyurea tank lining from SPI.
Initially the tank internals were prepared to SA2.5 by method of abrasive blasting, ensuring all existing coatings were removed. This is amongst the best methods of surface preparation available which is the keystone of any tank lining. The blast profile was measured for profile to ensure an optimum anchor for our lining system. We resourced two blast teams to the project to ensure that it was completed within the tight time scale.
Following preparation the tank was vacuum cleaned prior to priming using Chemco International RS500P surface tolerant epoxy primer applied by airless spray following a stripe coat of all angles and edges.
Once the primer had cured the polyurea tank lining was applied using our own WIWA spray equipment, with the polyurea being applied to a thickness of 2mm on the tank walls and 3mm on the tank floor. Because of the fast cure nature of the material the tank could be returned to service the same day.
The tank lining was tested for thickness using a dry film thickness gauge and for pin holing using a DC holiday spark tester.
The works were supervised by our in house paint inspector with a full quality assurance programme conducted. The client was extremely pleased with the speed and quality of the tank lining works.