FRP tanks are possible up to about fourteen feet diameter using either a filament winding or spray-up process. The thermoset resins used in both filaments wound and spray-up fabrication commonly include polyesters, vinyl esters and isophthalics.

Filament winding consist winding resin-impregnated glass fibers predetermined patterns. After the laminate layers are wound-on, the tank shell is allowed to cure at room temperature before secondary bonding operations begin.

Spray-up is an open molding fabrication method used to make FRP tank bottoms and dished tops and parts that have large surface are. Chopped fiberglass reinforcements and catalyzed resin are deposited onto a mold surface. Rollers or squeegees are used to remove entrapped air and work the resin into the reinforcements woven fabric is added to give the laminate greater strength.

Due to the corrosion resistant nature of FRP, the tank can be made entirely from the composite, or a second liner can be used. In either from the composite or a second liner can be used. In either case, the inner liner is made using different material properties than the structural portion and laminate.

The liner if made of FPR is usually resin rich and utilizes a different type of glass, called “C-Glass”, while the structural portion uses “E-Glass”. The thermoplastic liner is usually 2.3 mm thick (100 mils). This thermoplastic liner is not considered to contribute mechanical strength. The FRP liner is usually cured before winding or lay-up continues, by using either a BPO/DMA system, or using and MEKP catalyst with cobalt in the resin.

If the liner is not made of FRP, there are multiple choices for a thermoplastic liner. The engineer will need to design the tank based on the chemical corrosion requirement of the equipment. PP, PVC, PTFE, ECTFE, ETFE, FEP, CPVC,PVDF are used as common thermoplastic liners.

Due to FRP’S weakness to buckling, but immense strength against tensile forces and its resistance to corrosion, a hydrostatic tank is a logical application for the composite. The tank is designed to withstand the hydrostatic forces required by orienting the fibres in the tangential direction. This increases the loop strength, making the tanks anisotropically stronger than steel.

FRP which is constructed over the liner provides the structural strength requirements to withstand design conditions such as internal pressure or vacuum, hydroplastic loads, seismic loads (including fluid sloshing), wind loads, regeneration hydrostatic loads, and even snow loads.