The interceptor was allowing ground water ingress which could also mean that pollutants could enter the surrounding soil. A suitable tank lining was required that could also be installed over 1 weekend and the interceptor returned to service on Monday morning.
We proposed the application of Raven Linings 405 ultra high build reinforced epoxy tank lining. Not only is this tank lining ultra fast curing and able to be returned to service in as little as 6 hours, but also able to withstand a negative pressure of ground water. These two properties made this the ideal tank lining for this application.
Initially we assisted with cleaning and pumping out of the interceptor by pressure washing and using a degreaser to remove oil contamination to ensure optimum adhesion of the new lining.
Points of water ingress were resolved by drilling through the steel and inserting resin injection ports. Leaks were then resolved by injecting Normet Tampur 150 hydro reactive polyurethane resin. Once cured the packers were removed.
All surfaces to be coated were prepared to SA2.5 by method of abrasive blasting and ensuring that a minimum surface profile of 100 microns was achieved. As part of our standard quality assurance this was tested and recorded using a surface profile needle gauge.
The blast standard was maintained by sheeting in the interceptor and introducing dehumidification equipment. All spent blast media was removed and all surfaces vacuumed clean to again promote maximum adhesion of the new tank lining. The effectiveness of this was verified by dust tape method.
As per our standard quality assurance the climatic conditions were tested and recorded prior to and during coating application – despite Raven Linings 405 excellent damp tolerance.
This was applied by notched trowel to a target thickness of 6mm, with additional thickness applied to corners and areas of previous water ingress. This was finished as flat as possible using trowels and filling blades.
Once cured the lining was tested for pin holing using a DC holiday spark tester and dry film thickness readings taken and recorded. Any defects identified were marked and made good using the same material.
