Echo Square Services Ltd recently completed the full water tank reline and refurbishment of a 120,000 litre concrete water tank for a major London hospital.
The concrete water tanks internal surfaces were previously lined with an epoxy coating which had failed.
The underside of the water tanks roof was also coated with a non-compliant bituminous coating and all steel supports between the roof sections were heavily corroded.
To improve the flow of water through the tank it was required to reinstall the existing inlet float valve on to the opposite side of the water tank as it was positioned on the same side as the water tanks outlet which isn’t compliant with ACoP L8 guidelines.
Furthermore, the existing access into the tank was very poor with no fixed ladder in place.
We therefore commenced the water tank refurbishment project by installing a compliant GRP ladder to the inside of the water tank.
We then removed the existing float valve and installed stainless steel pipework from one side of the water tank to the other while also fitting a new Keraflo KB delayed action valve on the opposite side of the water tank to ensure the optimum circulation of water stored within the water tank would be achieved when the water tank was put back into service.
Water Tank Reline Preparation
The first stage of the water tank reline was to remove all existing non compliant coatings from all internal surfaces of the water tank and roof by utilising small mechanical hand tools.
Minor surface pitting was then filled with a polyurethane sealant.
Once all surface pitting was filled our operatives applied an epoxy resin based film primer to the water tanks internal concrete surfaces to consolidate the surface and improve adhesion of our polyurethane coating system.
Water Tank Coating Application
Following the application of the base primer we were in a position to apply a base coat (Grey) of ES 988 DWPU to all internal surfaces.
Once cured, the above was then repeated with a top coat of (Blue) ES 988 DWPU.
Water tank disinfection
Once the coating had cured, the water tank was cleaned & disinfected by the application of a 500ppm chlorine dioxide solution which was sprayed onto the water tanks internal surfaces.
Additional Water Tank Remedial Works
As part of the full refurbishment project we also fitted inline vermin screens to both the warning and overflow pipes
The non-compliant copper open vent pipework was also cut back and the hole in the lid was sealed and coated internally.
The original ball valve access hatch was also sealed in place using a polyurethane sealant.
With the major refurbishment now complete, our client was in a position to be place the system back into service