What is an ISO Tank?

ISO tank containers comply with the International Standard Organization (ISO) standards. They are suitable to transport both hazardous and non-hazardous bulk liquids.

ISO containers are made with stainless steel and housed inside a protective layer. The type of protective frame used depends on the tank’s contents. The ISO tank container features a manhole at the top for easy access and one valve each at the top and bottom.

In situations where there is unexpected liquid leakage due to an accident, containment berms or secondary storage tanks are helpful. Ironclad Environmental Solution’s tanks provide a safe temporary storage solution while you get your ISO tank repaired.

What is ISO Certification?

ISO certification is a globally recognized standard applicable to all business operations to ensure continued high standards. This means standardization of size, strength, and durability with regular inspections for compliance for the ISO containers. ISO containers should also include a Container Safety Certificate (CSC).

Types of Liquids That Can Be Stored in ISO Tank Containers:

  • Molasses
  • Milk and other dairy products
  • Alcoholic and non-alcoholic beverages
  • Liquefied sugars
  • Hydrogen peroxide
  • Sulfuric acid / Nitric acid
  • Chemicals / Solvents
  • Liquid food products
  • Heating oil / Vegetable oils
  • Gasoline / Diesel / Liquefied petroleum gas (LPG)
  • Liquid resins

ISO Tank Container Specifications (Sizes and Dimensions)

According to the ISO standards, a steel frame surrounds the tank container. The standard 20-ft frame encloses a tank that holds 21,000 liters (5,547 gallons) of liquid. The frame dimensions are:

  • Length – 20 ft.
  • Width – 8 ft.
  • Height – 8.6 ft.

Other sizes available in ISO tanks are:

  • 15,000 liters (3,963 gal)
  • 17,500 liters (4,623 gal)
  • 23,000 liters (6,076 gal)
  • 24,000 liters (6,340 gal)
  • 25,000 liters (6,605 gal)

General Specifications

  • Maximum gross weight: 36,000 kg (79,366 lbs.)
  • Working pressure: 4 bar (58 psi)
  • Test pressure: 6 bar (87 psi)
  • Allowable vacuum: .41 bar (12 in Hg)
  • Stacking weight: 9 high of 24,000 kg (ISO)

Tank Linings

ISO tanks use a protective lining for additional protection against corrosive liquids such as sulfuric acid and hydrochloric acid. The ship holds, rail cars, and over-the-road tank trailers use the same linings for protection.

Benefits of ISO Tanks

The 15,000-25,000 liter containers are a preferred choice for shipping a variety of goods because of the following factors:

  • High efficiency and safety.
  • Ease of transportation.
  • Standard size.
  • Enclosed in a mechanically stable frame with connections to lock them securely.
  • ISO tanks are easy to stack, just like a shipping container.
  • Reliable and cost-effective solution for transporting liquids in bulk. ISO tank containers have up to 30% lower shipping cost vs. over-the-road tankers.
  • The tanks can be designed to match the safety criteria of specific liquids.
  • ISO tanks are unlikely to leak and do not require additional packaging material.
  • It is possible to maintain a specific temperature for sensitive cargo.
  • The stainless steel body with added lining is highly resistant to corrosion. It can withstand temperature and pressure variations.
  • ISO tanks are a sustainable transportation solution with up to 50% less carbon footprint. They have a 15-20 year lifespan, which means you can use them more than other options.

Challenges Associated With an ISO Tank Container

Container Lifespan

If you pump solids into a container as high-pressure liquid, it may re-solidify in transit. You may have to do steam heating for the cargo to melt and drain out at the receiving end. You may also have to use air pressure to drain viscous material. This is not good for the overall life of the product. It can cause extraordinary stress on the shell, which can cause cracks and leaks.

Maintaining the Temperature

Temperature-controlled ISO tanks have inbuilt heating and cooling equipment that needs regular electrical supply from the ship or truck. This means that the electricity supply has to be reliable for the tank’s contents to remain safe.

Breaking/Chipping of the Protective Coating

Accidents and individuals working with heavy tools can cause minor scratches on the tank’s body. This can cause the protective coating to wear off gradually and expose the metal to the atmosphere or other corrosive materials. While workers can repair some protective coatings on the field, others may need complete sandblasting and recoating.

ISO Tank Container Maintenance

Accidents during loading, unloading, and transits, and changes in the temperature and pressure of the ISO tank can cause stress to the shell. There could be breaking or chipping of protective coating, which can expose the metal to corrosive liquids. ISO tanks require an inspection at least once in two years and a re-coat if needed.

ISO Tank Alternatives

Many of the challenges associated with an ISO Tank Container can be mitigated by other types of specialty equipment such as steel frac tanks, poly tanks, or stainless steel tanker trailers, depending on the application. Contact our team to learn more about our containment solutions and waste transportation services. We will be happy to help answer your questions and provide ideal solutions from our portfolio of products.


What is the need for a standard ISO container?

The design of ISO tank containers allows convenient, safe, environment-friendly and cost-effective transportation of hazardous and non-hazardous bulk liquids. With up to 30% less transport cost and up to 50% lower carbon footprint, containers are preferred compared to over-the-road transport.

What are the dimensions of an ISO container?

A standard ISO container is a horizontal cylindrical pressure vessel encased inside a 20′ x 8′ x 8.6′ steel framework.

How do you clean an ISO tank?

It is essential to completely remove any residual solid or liquid cargo and odor of contents and cleaning substance from the ISO tank containers.

  • Tanks should be cleaned at a certified cleaning terminal only. Food grade tank containers are cleaned at a separate facility.
  • Declare the previous cargo (hazardous or non-hazardous) to the facility superintendent.
  • Remove all discharge valves, pressure release valves, and other components for cleaning and inspection.
  • Normal steaming, low-caustic detergent-based cleaning, and pressure washing are the most preferred cleaning methods.
  • Circulation of 15-20% nitric acid before pressure washing with fresh water really helps.
  • A survey by an independent and qualified surveyor.
  • Clean with hot water spinners or steam sterilization.
  • Dry the container and seal the lids and valves.
  • Issue the cleanliness certificate.