American Petroleum Institute Tanks

At Southeastern Construction, we design and fabricate custom above ground, welded steel storage tanks that meet the exacting standards of the American Petroleum Institute (API).

API establishes standards for the design and fabrication of welded steel storage tanks for storing oil and other liquids. The API standard is applicable for stationary atmospheric and low-pressure petroleum storage tanks used in all sectors of the petroleum and petrochemical industry. We serve customers in the oil and gas industry and beyond for their custom, over dimensional, API certified storage tanks in carbon steel and stainless steel.

API Tanks Fabricated by Southeastern Construction with Construction Worker in Front with Blue Helmet

Decades of Experience

Southeastern Construction has decades of experience in designing, fabricating, assembling, and inspecting API 620 and API 650 storage tanks. We are proud to be an API Accredited 12-acre, 65,000 square foot manufacturing facility in West Central Florida. Our custom steel plate fabrication for your API storage tanks is made possible by our team of professional designers, welders, and fabricators.

Examples of API tanks that can be fabricated:


  • Flocculation tanks
  • Separator tanks
  • Petroleum storage tanks
  • Chemical storage tanks
  • Storage tanks
  • Sulfuric acid storage tanks
  • Bulk tanks
  • Caustic tanks
  • Caustic storage tanks
  • Sludge tanks
  • Diesel tanks
  • Underflow tanks
  • Amine storage tanks
  • Oily water tanks
  • Sulfuric acid tanks
  • Stainless steel tanks
  • Carbon steel tanks

API 620 Tanks

The design of API 620 tanks has a single, vertical, centered axis of revolution and is used for materials with higher internal pressures such as liquified natural gas and cryogenic tanks. The API 620 requires a flat or elevated bottom in order to properly store the steel tank.

API 650 Tanks

The design of API 650 tanks allows them to store gas, oil, chemicals, water, and biofuel for common steel tanks in the oil industry. API 650 tanks need even support for the whole bottom and stored in non-refrigerated facilities that have a maximum design temperature of 200 degrees Fahrenheit.

Steel API Tank Fabricated by Southeastern Construction Who is a Leader in Custom Steel Plate Fabrication

API Tanks are designed, fabricated, and delivered to your facility worldwide.

  • Meets API 620, API 650 standards
  • API storage tanks, available for carbon steel fabrication or stainless-steel fabrication
  • Oversized, super load, custom heavy storage tanks
  • Lined internally for special applications
  • Can be used across many industrial markets

API Tank Dimensions

We manufacture API tanks of various shapes and sizes to accommodate different capacities and applications. Diameters for API tanks can range from 36″ to 192″.


  • 36″ diameter tanks: Capacity up to 10,000 gallons (typically store smaller quantities of materials, such as on a drilling rig or at a small-scale production facility).
  • 48″ diameter tanks: Capacity up to 25,000 gallons (commonly used in small to medium-scale industrial applications).
  • 72″ diameter tanks: Capacity up to 60,000 gallons (suitable for larger industrial applications).
  • 96″ diameter tanks: Capacity up to 120,000 gallons (typically used in large-scale industrial applications).
  • 120″ diameter tanks: Capacity up to 220,000 gallons (commonly used to store petroleum or other chemicals).
  • 144″ diameter tanks: Capacity up to 320,000 gallons (suitable for larger-scale petroleum storage applications).
  • 192″ diameter tanks: Capacity up to 500,000 gallons (often used to store petroleum or other liquids in large-scale industrial facilities).

API Tank Industries Served

We serve the exacting needs of facility operators, EPC contractors, general contractors, and OEMs in oil and gas and multiple other industries.

Oil & Gas

Chemical Treatment

Food & Beverage Processing

Mining & Minerals


Power Generator

Water & Wastewater Treatment

Pulp & Paper

Waste Treatment


Contact Us for an API Tank Quote

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