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The Truth about Fibreglass Lining for Water Tanks

We often get asked if Fibreglass Lining is a good option to use to reline water tanks. Well, the honest answer is NO! And here’s why… Fibreglass Systems would never qualify for drinking water under DWI (Drinking Water Inspectorate) due to the various levels of styrene within fibreglass systems. View a completion report demonstrating some of the regular problems.

There have been many documented cases of water contamination from styrene following refurbishment of water tanks utilising fibreglass lining systems. This usually starts with a 'strong solvent-type smell' in the water, followed by a thin gelatinous layer that can usually be seen 'floating' on top of the water in the tank. When the tank is used for activities such as drinking tap water, eating foods prepared with tap water, bathing, showering, etc., then the styrene content in the water (apart from tasting badly) can potentially:

  • Cause acute irritation to the eyes, nose, throat and skin.
  • Gastrointestinal symptoms such as abdominal pain and diarrhoea often referred to as the "Styrene Sickness".
  • At high levels, chronic bronchitis type symptoms and other respiratory symptoms can appear.
  • Multiple central and peripheral acute nervous system effects have also been described, but some neurological symptoms and colour vision impairment may also appear at much lower levels.
  • In the past, the so called "Styrene Sickness" has been described by workers exposed to styrene as: nausea and vomiting, loss of appetite and general weakness.

Osmotic Blistering via fibreglass lining

The problem faced by all engineers who are responsible for the maintenance of potable water 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 in the fibreglass. And often, these cannot be seen with the naked eye. These cavities and cracks allow bacteria to nest and proliferate.

The problems start to occur when the water molecules migrating into the fibreglass encounter other chemicals inside the laminate, primarily water-soluble materials (WSMs) such as the emulsion binders or resin used to hold the glass mat together, or pockets of uncured or only partly cured resins. 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 fibreglass. These larger molecules are then trapped. This is the point at which osmosis actually starts.
Osmotic blistering of the fibreglass substrate due to water permeation can also lead to deterioration of the gel coat and, subsequently, a surface that is highly likely to harbour and promote the growth of micro-aquatic organisms.

If ignored, internal water osmotic blisters will eventually burst putting their contents into the potable water. These chemicals not only have a very unpleasant taste but are also toxic! For this reason, fibreglass lining is not recommended or approved by the DWI for drinking water tanks.
Find out morehere.

Fibreglass systems also causes water ingress

Another common fault associated with fibreglass coatings is failure due to water entrapment. Fibreglass Systems are often used in combination with slow curing epoxy resins and gel coats, which are extremely slow curing and are subsequently susceptible to 'holidaying' or 'pin-holing'. There is also very little adherence between the substrate of the water storage tank and the fibreglass lining. The water then traverses through these holes and travels between the tank substrate and the fibreglass lining. This continues until the fibreglass lining becomes detached from the substrate and partial, if not complete, failure occurs.

Call us Now and speak to one of our experts who will guide on the safer alternatives. Call us on 0800 772 3367.

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COVAC Credentials for Water Tank Refurbishment and Repair

COVAC Credentials for Water Tank Refurbishment and Repair