FRP Guides

FRP Storage Tanks: A Guide to Design, Standards and Selection

In short: FRP (GRP) storage tanks hold acids, alkalis, salt solutions, process water and drinking water without the corrosion that attacks carbon steel. A well-built tank has an inner corrosion barrier made of a resin-rich liner and veil, and an outer structural layer that carries the pressure and loads. Tanks are usually made by filament winding or contact molding and designed to a recognized standard such as ASTM D3299, ASME RTP-1 or EN 13121. The single most important decision is choosing the resin for your exact chemical, concentration and temperature.

FRP Storage Tanks: A Guide to Design, Standards and Selection – In short summary: key points at a glance

Where FRP tanks are used

Hydrochloric, sulfuric and phosphoric acid storage (resin selection is critical)
Sodium hypochlorite and caustic soda in water treatment
Plating, pickling and electronics chemical lines
Fertilizer and food processing
Potable water, fire water and rainwater
Wastewater, sludge and leachate

See our FRP hydrochloric acid tanks, FRP water tanks and filament-wound products, or browse the tanks, pipes and covers collection.

FRP Storage Tanks - Manufacturing: How FRP tanks are made — Manufacturing: How FRP tanks are made.

How an FRP tank wall is built

1. Inner surface (liner)

A resin-rich layer reinforced with a C-glass or synthetic veil. This is the surface the chemical touches, and it provides most of the corrosion resistance.

2. Interior layer

Several layers of chopped strand mat that back up the liner. Together with the inner surface, these layers are often called the corrosion barrier. They are not normally counted as load-bearing in the structural design.

3. Structural layer

Filament-wound roving or alternating mat and woven roving that carries hydrostatic pressure, wind, seismic, snow and nozzle loads. Its thickness is calculated from the design standard.

4. Exterior layer

A resin-rich outer coat with UV inhibitors or pigment. It protects outdoor tanks from weathering.

Manufacturing methods

Method	How it works	Typical use
Filament winding	Resin-wet continuous rovings are wound onto a rotating mandrel at controlled angles	Cylindrical shells, large vertical tanks, pipes
Contact molding (hand lay-up / spray-up)	Mat and woven roving are laid into a mold and rolled out	Heads, bottoms, small or non-cylindrical tanks, fittings
Sectional panels	Molded flat panels bolted together on site	Water storage tanks, especially rooftop or modular installations

FRP Storage Tanks - Design standards: Name a current standard — Design standards: Name a current standard.

Design and fabrication standards

ASTM D3299: above-ground, vertical, atmospheric-pressure glass-fiber-reinforced thermoset resin corrosion-resistant tanks. The 2026 edition (D3299-26) covers tanks made by filament winding or contact molding.
ASTM D4097 (contact-molded tanks) was withdrawn in 2026 and replaced by D3299-26. Older specifications that cite D4097 should be updated.
ASME RTP-1: stationary reinforced thermoset plastic corrosion-resistant vessels at pressures not exceeding 15 psig internal and/or 15 psig external above any hydrostatic head. ASME also runs an RTP certification program for fabricators' quality systems.
BS EN 13121: GRP tanks and vessels for use above ground, in several parts covering materials, design and fabrication.

Each standard sets laminate requirements, minimum thicknesses and inspection rules. Tell us which standard your project requires. We will confirm what we can design to and which documents we can provide. We do not claim third-party accreditation or stamps unless they are documented for your order.

Choosing the resin

Resin choice depends on the chemical, concentration and maximum temperature:

Isophthalic polyester: water, mild chemicals and food-grade water applications with suitable formulations
Vinyl ester: most acids, alkalis, hypochlorite and solvents within the resin manufacturer's limits; the most common choice for chemical tanks
Specialty vinyl esters: for higher temperatures or more oxidizing service

Use the resin manufacturer's chemical resistance guide for your exact conditions, and see our FRP chemical resistance guide and resin comparison. Some services, such as hydrofluoric acid or strong oxidizers, require special veils or materials.

Nozzles, fittings and accessories

Flanged nozzles (inlet, outlet, overflow, vent, drain), sized to your piping. See our FRP flanges
Manways on the side or roof
Level gauges and instrument connections
Lifting lugs and hold-down lugs for wind or seismic anchoring
Ladders, platforms and handrails in FRP. See FRP ladders and cage ladders

Nozzle reinforcement and gusseting are part of the design. Ask for the nozzle schedule and orientation drawing before fabrication.

FRP Storage Tanks - What to send for a quote: FRP tank RFQ checklist — What to send for a quote: FRP tank RFQ checklist.

Installation and support

Vertical flat-bottom tanks need a flat, smooth, level foundation, often with a resilient pad, so the bottom is fully supported.
Anchor tanks for wind and seismic loads as designed.
Do not apply pipe loads to nozzles. Support pipes independently and use flexible connectors where movement is expected.
Protect tanks from impact during handling, and use the designated lifting lugs only.

Inspection and maintenance

Inspect periodically for surface crazing, blistering, discoloration, cracking around nozzles and damage to the exterior layer. Internal inspection of the corrosion barrier during shutdowns is the best indicator of remaining life. Keep records of chemicals and temperatures, because changing the service can change the resin suitability.

Customization

Every FIBROVX tank is built to order: capacity, diameter and height, vertical or horizontal layout, resin and veil, nozzle schedule, color, insulation, ladders and platforms, and OEM labeling. Send a data sheet or sketch and we will propose a design.

RFQ checklist

Stored chemical, concentration, specific gravity and operating/maximum temperature
Capacity, preferred diameter and height, vertical or horizontal
Design standard required (for example ASTM D3299-26, RTP-1, EN 13121)
Design pressure or vacuum (if any), wind and seismic data
Nozzle list with sizes, flange standard and orientation
Indoor or outdoor; insulation or heating
Accessories: ladder, platform, level gauge, manway
Quantity and destination port

Need a quote or a drawing check?

FIBROVX manufactures FRP products in our own factory in China and builds every item to order: sizes, resin system, color, molds and OEM branding. Send your application, dimensions or drawing, quantity and destination port.

Request a Quote

Key terms

Corrosion barrier: The resin-rich inner layers of a tank wall that face the stored chemical.

Watch: FRP Storage Tanks in 27 Seconds

A 27-second visual summary: FRP Storage Tanks (captions on screen).

Larger than a truck: field-wound tanks

Shop-built tanks are limited by road transport. Above that, tanks are wound on site: field-wound FRP storage tanks run from DN4000 to DN25000 with capacities up to 5,000 m³ per tank, on a reinforced-concrete foundation prepared to our drawing. See field-wound FRP tanks for large storage.

FAQ

How long do FRP tanks last?

Service life depends on resin selection, temperature, operation and inspection. Correctly specified FRP tanks are widely used for long service in corrosive chemicals. Regular inspection is the best way to confirm remaining life.

Can FRP tanks store drinking water?

Yes, with suitable food-grade or potable-water resin systems. If your project requires a specific potable water approval, state it in your inquiry so we can confirm what documentation is available.

Which is better: FRP or polyethylene tanks?

Polyethylene is economical for small sizes and many chemicals at ambient temperature. FRP is used for larger volumes, higher temperatures, custom geometries and where structural rigidity is needed.

What does RTP-1 cover?

ASME RTP-1 covers stationary reinforced thermoset plastic corrosion-resistant vessels at pressures not exceeding 15 psig internal and/or 15 psig external above any hydrostatic head. It includes design, fabrication and inspection requirements, and ASME certifies fabricators under a separate RTP program.

Can you make horizontal or underground tanks?

Yes. Horizontal tanks with saddles and underground tanks with ribs are designed differently. Tell us the installation conditions. See also our FRP septic tanks guide.

Related guides

Sources

ASTM International, D3299-26 "Standard Specification for Glass-Fiber-Reinforced Thermoset Resin Corrosion-Resistant Tanks": https://store.astm.org/d3299-26.html
ASTM International, D4097-19 "Contact-Molded ... Tanks (Withdrawn 2026)": https://store.astm.org/d4097-19.html
ASME, RTP-1 "Reinforced Thermoset Plastic Corrosion-Resistant Equipment": https://www.asme.org/codes-standards/find-codes-standards/reinforced-thermoset-plastic-corrosion-resistant-equipment
BSI, BS EN 13121 "GRP tanks and vessels for use above ground": https://knowledge.bsigroup.com/products/grp-tanks-and-vessels-for-use-above-ground-raw-materials-specification-conditions-and-acceptance-conditions