Composite Tanks: Which Industries Use Them, and Why

What is a composite tank?

Glass fibre reinforced plastic — written GRP or FRP in international correspondence, CTP in Turkish — is glass fibre bound together with resin. The fibre carries the load, the resin holds the fibre together and meets the stored liquid.

That combination produces a set of properties no single metal or concrete offers on its own: a surface that does not rust, a shell that is markedly lighter than steel, and a geometry that can be set by the project rather than by a catalogue.

Why composite instead of steel or concrete?

It is the question we hear most, and the answer rarely sits under a single heading.

• Corrosion: Composite does not rust. Brine, salt water, acidic and alkaline media work away at metal surfaces over time; a composite shell does not enter that reaction. Recoating, painting and rust repair leave the maintenance schedule.
• Weight: For the same volume it is far lighter than a steel tank. That eases transport, crane selection, site installation and relocation later on, and it lowers the cost of the foundation and supports.
• Hygiene: A smooth internal surface is easier to clean and does not hold deposits — one of the first things asked for in food and drinking water duties.
• Thermal behaviour: Composite conducts heat far more slowly than metal, so swings in ambient temperature reach the contents more gradually.
• Freedom of form: Moulds and winding lines allow diameter and length to follow the project instead of a standard catalogue size.

Which industries use them?

The range widens in step with how aggressively the stored liquid treats metal.

Food and brine: Olives, pickles, vinegar and brined products carry a high salt load, and salt is abrasive to metal. Olive curing and storage tanks are among the most established composite applications.

Water and rainwater: Drinking water reservoirs, rainwater harvesting and underground water tanks — where hygiene and corrosion resistance are wanted together.

Chemical and process: Acid storage, dosing, process and reaction tanks, double-walled solutions. Here the resin is selected directly against the chemical to be stored.

Treatment: Biological and industrial treatment tanks, biodiscs, septic solutions — a permanently wet and chemically active environment.

Agriculture and industry: Silos, vehicle-mounted tanks, gas scrubbing towers and modular water reservoirs.

Beyond tanks: profiles, sheets, gratings

Composite is not limited to storage. The same material becomes a structural element through different processes.

Pultruded profiles are drawn continuously through a die with the fibre saturated in resin, and they replace steel structures in corrosive environments. Flat sheets are used in roof and facade cladding, skylight panels, and agricultural and industrial buildings. Composite gratings give a non-slip, non-rusting platform surface in wet and chemical areas. SMC and BMC moulding covers series-produced composite parts.

What does the production method change?

In short: geometry and repeatability.

Filament winding lays resin-saturated fibre onto a rotating mandrel at a controlled angle, giving a high and consistent glass content on cylindrical shells. Contact moulding takes over where winding cannot reach — nozzles, knuckle transitions, bespoke detail. Most tanks contain both.

Pultrusion produces continuous profiles; moulding produces series parts. Which one is used is not a preference, it follows from the geometry of the product.

How is the right solution decided?

The idea of a "standard product" carries less weight in composite than it does in metal, because the three things that decide the design differ on every project: what will be stored, at what temperature it will operate, and what dimensions are required.

Once those three are clear, material selection, shell design and production method follow from them. That is why our conversations usually start with those three questions rather than with a catalogue.

Tell us which liquid, under what conditions and in what volume you need to store, and our engineers will work through the right solution with you.