Steel vs Fiberglass Tanks: Choosing the Right Material

When it comes to industrial fluid storage, few decisions are as critical as choosing the right tank material. The most common choices, steel tanks vs fiberglass tanks, each bring unique advantages and considerations depending on the environment, stored material, and long-term maintenance expectations.

At Smith Industries, where custom steel storage tanks are designed and fabricated to meet API 12F and 12D standards, the choice of material is a matter of performance, reliability, and longevity. Understanding the strengths and limitations of both steel and fiberglass helps operators make informed decisions that optimize cost, durability, and operational safety.

Understanding Steel Tanks

Steel tanks have been the cornerstone of industrial storage for decades. They are favored for their high strength, structural stability, and ability to withstand both internal and external pressures. In industries such as oil and gas, chemical processing, and water treatment, steel tanks are a trusted standard for bulk liquid storage.

Advantages of Steel Tanks

1. Superior Strength and Structural Integrity

   Steel’s tensile strength allows it to hold heavier loads and maintain its form even under extreme stress. This is particularly important in high-pressure applications or in regions with harsh environmental conditions.

   For instance, carbon steel and stainless steel variants are often selected for tanks that handle corrosive or high-temperature substances.

2. Versatility in Design and Fabrication

   Steel can be cut, rolled, and welded into virtually any configuration. This flexibility allows manufacturers like Smith Industries to produce low-profile, cone-bottom, or flat-bottom tanks in capacities ranging from 100 to 1,000 barrels and beyond. Custom fittings, manways, and coatings can be applied to meet project-specific standards.

3. Long Service Life with Proper Maintenance

   When maintained and coated properly, steel tanks can last for several decades. Periodic inspections, protective linings, and cathodic protection systems help prevent corrosion and preserve structural integrity.

4. Recyclability and Environmental Sustainability

   Steel is 100% recyclable. According to the U.S. Environmental Protection Agency (EPA), steel has one of the highest recycling rates of any industrial material, reducing lifecycle emissions and waste.

Limitations of Steel Tanks

While robust, steel tanks are susceptible to corrosion if left unprotected in harsh or humid environments. Uncoated and unpainted steel, such as those stored outdoors before finishing, will naturally form a rust layer that must be treated before use.

Additionally, fabrication and transportation costs can be higher due to weight. The maintenance requirements, such as repainting or relining, also need to be factored into long-term ownership costs.

Understanding Fiberglass Tanks

Fiberglass Reinforced Plastic (FRP) tanks offer an alternative material that combines strength with corrosion resistance. They are made by layering glass fiber and resin, creating a composite that resists degradation from chemicals and moisture.

These tanks are commonly used in water and wastewater treatment, agricultural storage, and applications involving caustic or acidic liquids.

Advantages of Fiberglass Tanks

1. Exceptional Corrosion Resistance

   One of fiberglass’s biggest advantages is its natural resistance to corrosion. Unlike uncoated steel, fiberglass does not rust or degrade when exposed to water or most chemicals, making it suitable for environments with constant moisture or aggressive chemical content.

2. Lightweight and Easy to Install

   Fiberglass tanks weigh significantly less than steel, simplifying transportation and installation. This makes them an attractive option for projects with limited equipment access or budget constraints for heavy rigging.

3. Low Maintenance Requirements

   Fiberglass requires minimal upkeep. There is no need for protective coatings, and the material does not require periodic inspections for corrosion in most standard applications.

4. Cost Advantages for Certain Applications

   For smaller tanks or systems storing non-pressurized, non-flammable liquids, fiberglass can be a more economical solution due to its lower production and installation costs.

Limitations of Fiberglass Tanks

Despite their corrosion resistance, fiberglass tanks have several limitations that must be considered before selecting them for industrial applications:

• Lower Strength and Pressure Tolerance:

  Fiberglass cannot withstand the same internal pressures as steel. It is unsuitable for pressurized or high-temperature fluids.

• Susceptibility to UV and Impact Damage:

  Prolonged exposure to sunlight can weaken the resin matrix, and impacts during handling can cause microcracks that compromise long-term performance.

• Limited Sizing for Large-Capacity Storage:

  Manufacturing very large fiberglass tanks (1,000 barrels or more) can be challenging, often requiring multiple segments or on-site assembly, which can increase project complexity and cost.

• Repair Complexity:

  While fiberglass can be patched, the repair process is more complex than welding steel and often requires specialized materials and curing time.

According to ASTM International, fiberglass tank design and testing must adhere to stringent standards such as ASTM D3299 and ASTM D4097, which specify fabrication requirements for filament-wound and contact-molded tanks.

Comparing Steel vs Fiberglass Tanks

Feature	Steel Tanks	Fiberglass Tanks
Strength	Very high structural and pressure strength	Moderate; not suitable for high pressure
Corrosion Resistance	Requires coating or lining	Excellent inherent resistance
Lifespan	20–40+ years with maintenance	15–30 years depending on use
Maintenance	Periodic repainting, inspection, and protection	Minimal maintenance required
Weight	Heavy, requires lifting equipment	Lightweight, easy to install
Cost (Initial)	Higher upfront cost	Lower upfront cost
Cost (Lifecycle)	Lower over time with maintenance	Can be higher if repairs are needed
Temperature/Pressure Applications	Suitable for extreme conditions	Limited to ambient or mild environments
Customization	Easily fabricated to any size or shape	More limited in geometry and scalability
Recyclability	Fully recyclable	Difficult to recycle

Industry Use Cases

1. Oil and Gas Operations

   Steel tanks are the industry standard for crude oil, produced water, and chemical storage. They handle high pressure, extreme temperatures, and can be fabricated to meet API and ASME codes.

2. Chemical and Wastewater Facilities

   Fiberglass tanks are ideal for storing acids, alkalis, and non-flammable liquids that could corrode metal surfaces. They are also popular for underground storage due to their corrosion resistance.

3. Agricultural and Municipal Applications

   For storing fertilizers, potable water, or wastewater, fiberglass provides a cost-effective and maintenance-light solution, especially for smaller volume tanks.

4. Renewable Energy and Power Generation

   Steel tanks, like those fabricated by Smith Industries, are increasingly used in energy production for fuel storage, process fluids, and water containment systems in both conventional and renewable power plants.

Factors to Consider When Choosing Between Steel and Fiberglass

• Fluid Type: Is it corrosive, flammable, or high temperature? Steel is better for volatile or pressurized substances, while fiberglass suits non-reactive or corrosive fluids.

• Location and Environment: Outdoor installations with UV exposure or marine air may require coated steel or fiberglass, depending on application.

• Budget and Lifecycle Costs: Steel’s higher initial investment can be offset by its longevity and recyclability.

• Regulatory and Code Requirements: Some projects, especially in oil and gas, require tanks built to API 12F or ASME Section VIII standards, specifications typically fulfilled by steel tanks.

• Maintenance Capabilities: Consider whether your facility has the resources to maintain steel coatings or prefers the lower maintenance profile of fiberglass.

Why Smith Industries Specializes in Steel Tanks

At Smith Industries, our fabrication process focuses on strength, customization, and long-term durability. Every steel tank is designed to meet or exceed API, ASME, and customer-specific standards. From unpainted and uncoated low-profile tanks to fully finished and coated systems, we tailor every build to the operational needs of the client.

Our experience fabricating 1,000-barrel steel tanks, like the one shown above, demonstrates the scalability and reliability that steel provides. Each unit undergoes rigorous inspection for weld quality, dimensional accuracy, and leak prevention.

Whether for upstream oil storage, midstream infrastructure, or industrial process systems, Smith Industries continues to set the standard in steel tank fabrication, offering superior performance where strength, reliability, and longevity are non-negotiable.