THE PROBLEM
The existing EPDM liner had split and the tank was leaking heavily, resulting in the wasting of water which was leading to additional operational costs for the client.
THE SOLUTION
We proposed the application of a seamless spray applied polyurea lining to resolve the water egress.
Removing the old tank Lining
The old water tank liner was unbolted and cut into sections so that it could be removed from the tank manway. This exposed the galvanized internals that were beginning to show breakdown and corrosion.
Preparing the tank for relining
The tank internals were prepared by method of abrasive blasting, preparing any exposed steel to SA2.5 as per ISO8501-1 and the remaining galvanizing sweep blasted with a minimum surface profile of 75 micrometers. The concrete tank floor was abrasive blasted to remove surface laitance and contaminants.
One prepared all surface were vacuumed clean and a surface cleanliness test conducted.
Applying the epoxy primers
The tank floor was double primed using a damp tolerant epoxy primer to fully seal the slab and prevent any outgassing in the new polyurea tank lining.
To avoid the need to hold the blast standard with costly dehumidification any exposed steel was primed using Corroless EPF rust stabilizing epoxy primer.
At the floor/wall intersection a fillet detail was installed using a polyurethane jointing compound to fill the void and isolate this potential point of movement.
Spraying the Polyurea Tank Lining
Once prepared and primed SPI HT100F UB was spray applied using one of our WIWA PU460 plural spray units to a thickness of 2mm. The polyurea lining was tested for pin holing using a DC holiday spark tester to check for pin holing, where found these where marked with chalk prior to touching in using the same polyurea material.
Finally the top edge of the lining was sealed using a polyurethane jointing compound to protect the top edge of the new tank lining.
