GRP Tank Repair Case Study

These images show the GRP tank before any preparation work and then after preparation. The GRP tank was fully relined with Acothane DW. If you are looking a GRP tank repair Acothane UK can help, we are one of the UK’s leading tank repair and GRP water tank reline specialists.

The problem

GRP water tank with cracks needs reliningMost engineers who replace their steel water storage tanks for brand new plastic tanks or GRP water tanks believe that this is the ‘ultimate’ solution. Unfortunately, having now repaired and relined literally hundreds of GRP water tanks, we know this not to be the case.

We are constantly being asked to repair and reline GRP tanks, some of which are only months old. This is because the problem faced by all engineers who are responsible for the maintenance of glass reinforced plastic tanks is that even with regular cleaning and chlorination, bacteria such as micro-aquatic organisms will continue to multiply as they are protected in the habitat provided by air filled cavities and fine cracks that often cannot be seen with the naked eye.

These cavities and cracks in the internal substrate allow bacteria to nest and proliferate. The problems start to occur when the water molecules migrating into the GRP tanks encounter other chemicals inside the laminate, primarily water-soluble materials (WSMs) such as the emulsion binders used to hold the glass mat together before it is moulded.GRP tank damaged from bacteria growth

The water molecules can then have a chemical reaction with these substances, forming larger molecules of a new chemical, often acidic – which unlike the original small water molecules, cannot carry on passing through the GRP. These larger molecules are then trapped. This is the point at which osmosis actually starts. Osmotic blistering of the GRP substrate due to water permeation can also lead to deterioration of the gel coat and, subsequently, a surface which is highly likely to harbour and promote the growth of micro-aquatic organisms.

It should be considered that, if not looked after and ignored, such internal water osmotic blisters will burst putting their contaminated contents into the potable water. These chemicals not only have a very unpleasant taste but are also toxic! For this reason, GRP is not recommended or approved by the DWI (Drinking Water Inspectorate) for drinking water storage tanks. There can also be numerous areas of corrosion to the steel fastenings which hold the glass reinforced plastic tank panels together.

Black spore fungi is also common in GRP tanks and is notorious for spreading, predominantly where there is a combination of water and air at an ambient temperature. These spores tend to multiply very quickly and produce a grey or black jelly-like growth on the internal GRP surface.

The Solution

Acothane DW offers numerous economic, technical and environmental features and benefits for use in the repair and relining plastic potable water storage tanks and structures, some of which are highlighted as follows:

  • WRAS/DWI approved.
  • Completely Solvent Free Technology.
  • Superb adhesion to plastic tank substrates.
  • Prevents steel fasteners from corroding.
  • Provides a completely waterproof membrane, preventing any potential ingress of water which can cause osmotic blistering, air filled cavities and cracks.
  • Leaves a surface which has a tough, easy clean, ceramic, tile-like surface combined with elongation properties of up to 35% which will adequately cope with any potential movement of the plastic tank.
  • Proven to resist the growth of bacteria such as micro aquatic organisms and black spore fungi.
  • Provides protection of the existing mastic between the plastic tank joints against potential attack from chemicals and subsequent deterioration and consequential leaks.
  • High levels of impact and chemical resistance.
  • Reduced downtime due to extremely fast cure times.
  • Long life performance with minimal maintenance.
  • Superb anti-erosion/corrosion properties.
  • Long term guarantee on completion.
  • Excellent track record having been utilized for the repair and relining of plastic tanks by many high profile clients.