Concrete Water Tank GRP Lining System | Specialist Lining Services by Eurotank

Concrete Water Tank Repair | Ulverston, Cumbria

Specialist Lining Services by Eurotank offer a number of solutions for the repair of water tank linings. In this example, a concrete water tank GRP lining was required.

We were called in to carry out a re-lining of two water production test tanks at a company based in Ulverston, Cumbria. The tanks were suffering from catastrophic coating failure. This was due to poor adhesion from the epoxy to an unprepared substrate. The tanks were in a sensitive location in a laboratory environment. It was essential that we kept the area clean as well as managing the odour during the GRP lining process. Due to the sensitive area, Specialist Lining Services by Eurotank carried out the abrasive blasting preparation at the weekend. The lining process was carried out at night to prevent hampering the companies’ production.

Safety Precautions

Specialist Lining Services by Eurotank worked on the design of a self-sufficient temporary work tent. This offered us a level of protection, to prevent abrasive ricochet leaving the work area. Whilst also acting as an extraction system to draw abrasive dust and solvent fumes to the outside. Due to the type of open-topped tank, we utilized a scaffold tower with outriggers to act as a platform to attach our confined space safety winch. During both processes, the temporary tent worked to its full potential on both the preparation and the lining. All machinery and the floor area were also masked to keep a completely clean environment.

The Importance of Preparation Prior to Installing a GRP Lining System

At Specialist Lining Services by Eurotank , preparation is 90% of our work when installing a GRP lining system. For these tanks we chose abrasive blasting. Also known as sandblasting, this method removes all coatings, surface additives contamination, and provides an-etch for the lining to adhere to. Both tanks had a white concrete screed and a failed epoxy coating system to remove. The original concrete cast needed exposing for our lining system to adhere to the tank. The abrasive garnet was chosen due to its hard angular and low dust levels for this application. Once the blasting was complete the tank was completely cleaned out and dry vacuumed. It was now ready for the resin prime.

Tent encapsulation for concrete water tank GRP installation

Our tank lining operatives then primed the concrete using Isophthalic resin to seal. Priming also aids in the absorption of the resin in the substrate when carrying out the lining system. Whilst the operatives waited for the resin primer to dry, they cut the chopped strand matting and the chemical resistant tissue to size for the glass reinforced plastic lining system.

We then began laying two layers of 450csm matting to the tank. This was embedded in an Isophthalic resin. The first layer was overlapped 50mm to create a reinforcement of the GRP lining system. The second layer of CSM was staggered and laid up edge to edge to create a seamless finish to the lay-up. The Entire matting layup (laminate) could be left to dry before application of the next stage of the system.

Chlorine Resistant Vinyl Ester Resin

Due to the high chlorination of the water the tank would be holding, it was of the utmost importance to protect the matting system. Vinyl ester resin was chosen due to it’s resistance to Chlorine water. The tank was hand sanded using 80 grit sandpaper to remove any imperfections in the matting system. The Operatives would then wet the wall using vinyl ester resin before carefully applying the chemical resistant tissue to the walls of the tank. The floor was then coated with a flood coat of vinyl ester to protect the matting on the floor area. This was left to dry over a 4-hour period before the next stage.

continuing with the protection of the matting and tissue lay-up, a vinyl ester resin coat pigmented in RAL 5012 was applied by rollers. This served to give the tank colour and to also protect the laminate from future osmosis due to chlorine attack. Once the Coat had dried sufficiently, Specialist Lining Services by Eurotank operatives would sand the entire tank using handheld sanders to create adhesion for the final gel coat.

A Specialist NPG gel coat with high chemical resistance to chlorine and many other chemicals were used. This was applied by rollers and finished with a brush to give an even finish to the tank. The tank was then post-cured using a heater before refitting tank furniture.

For more information on concrete water tank GRP linings contact us or call direct on 01782 969939