What is an ISO Tank Container?

An ISO tank container is a cylindrical pressure-rated vessel mounted in a 20-foot intermodal frame that meets International Organization for Standardization specifications. Unlike a dry box, it is engineered to carry bulk liquids, food-grade products, gases, and selected chemicals across road, rail, and sea. A typical ISO tank combines a stainless-steel barrel, insulation, and protective end frames for safe transportation in harsh shipping environments. Operators choose this format for repeatable cleanliness, faster logistics, lower handling risk, and long service life when compared with drums or flexi bags, making it a resilient solution for modern supply chains.

In this article, we will explore what is an ISO tank, what types there are, and how they can be used for your specific purpose.

The History of ISO Tank Containers

Bulk liquid tankage evolved as shipping modernized. Standardized frames emerged alongside the first ISO shipping containers, allowing liquid cargo to ride on the same vessels and railcars as boxes. Early adoptions accelerated during major military deployments, where rugged, stackable equipment improved supply speed and asset utilization. Over time, food-grade and chemical grades diversified, and today you will see specialized linings, heating systems, and gas-rated shells used from refineries to medical manufacturers. For perspective on dry modules that share the intermodal DNA, browse our storage containers. The same corner castings and steel frames that revolutionized dry freight also underpin liquid tank interoperability.

Types of Liquids Can Be Carried in ISO Tank Containers

1. Molasses: Heavy, viscous cargo often moved in insulated, steam-traced tanks to maintain temperature for pumping.

2. Milk and other dairy products: Food-grade stainless steel with polished interiors, CIP-friendly valves, and strict hygiene controls for sanitary products.

3. Alcoholic and Non-Alcoholic Beverages: Spirits, wine, and concentrates benefit from inert gas blanketing and odor-free seals in ISO tanks.

4. Liquefied sugars: Heated tanks with consistent thermal profiles to avoid crystallization during transportation.

5. Hydrogen Peroxide: Dedicated chemical service with compatible gaskets and rigorous oxygen-stable design.

6. Sulphur Acid / Nitric Acid: Specialty-lined or alloy tanks selected for corrosive chemicals and strict venting protocols.

7. Chemicals / Solvents: From glycols to ketones, deployed under the appropriate IMO/UN ratings with pressure relief systems.

8. Liquid Food Products: Edible oils, juices, and syrups are handled in a clean, sealed ISO container that maintains temperature and taste.

9. Heating oil / Vegetable oils: Often insulated with heating coils for viscosity control, a dependable option for long routes.

10. Gasoline / Diesel / Liquefied petroleum gas: Dedicated gas-rated units and baffle configurations tailored to volatility and pressure limits.

11. Liquid Resins: Viscous cargos moved in heated or agitated tanks to preserve processability upon arrival.

Safety and efficiency are synonymous with ISO tank containers. Besides moving significant volumes with less handling, tanks are extremely durable. A quality unit is designed for a long service span, commonly 20 to 35 years, allowing repeat use that delivers strong lifetime value and predictable business performance.

ISO Containers Certification

The International Organization for Standardization sets dimensional and performance benchmarks so tanks interchange safely worldwide. Each ISO tank container is built to verified criteria for frame strength, shell thickness, and lifting tolerances. During production, welds and pressure boundaries undergo stringent inspection, and only then is a Container Safety Convention (CSC) plate issued. Ongoing in-service tests, including visual exams and periodic pressure checks, keep the asset compliant for logistics partners across borders. Certification aligns owners, shippers, and carriers on reliability, transportation safety, and traceable quality.

ISO Tank Container Types

Choosing the right build begins with cargo characteristics. Heat sensitivity, corrosivity, food safety, and pressure define the spec. Below is a concise guide to common ISO tank container types used in global trade.

These categories help align cargo to spec so the ISO bulk liquid container delivers predictable performance with fewer handling challenges.

Dimensions of ISO tank containers

A tank built to ISO geometry fits cranes, twist locks, and stack plans across modes, keeping transportation simple. While the frame mirrors standard lengths, capacity varies by shell diameter, insulation, and service rating. Many programs center on 20ft units; specialized swap bodies appear in 40ft and 45ft formats where regional rules permit larger volumes.

Actual numbers depend on maker, service rating, and route constraints. Match capacity to density, fill limits, and route weight rules to protect shipping efficiency and compliance.

How Much Do ISO Tank Containers Cost?

The price of a tanker container depends on build spec, certification, and route demands. A food-grade bold often costs less than a corrosive-service build with special linings, steam coils, and upgraded valves. Buyers evaluate purchase versus one-way lease, factoring depot cleaning, periodic tests, and repositioning. New builds offer longer cycles before major work; used units lower entry cost but may need earlier refurbishment. Total ownership cost also includes logistics surcharges, transportation permits on certain corridors, and lane imbalances that affect backhaul supply. A practical budget compares three scenarios: buy, term lease, and hybrid pools for seasonal volume.

Typical cost drivers:

• Material and finish: shell thickness, polish level, insulation, and steel grade

• Thermal package: steam coils, electric tracing, or refrigerated control

• Cargo class: food, general chemicals, or high-corrosion media

• Compliance pathway: CSC plate, periodic pressure tests, and route approvals

• Utilization plan: turns per year, cleaning cycles, and depot availability

Well-run fleets track cleaning chemistry against cargo mix to avoid liner damage and extend lifecycle. Even when headline price is higher than drums or flexi bags, a bold can win on repeat use, reduced handling, and fewer losses.

Benefits of ISO Tank Containers

There are meaningful advantages to choosing an ISO container for bulk liquids and sensitive products:

• Internationally standardized with verifiable quality, giving shippers and carriers shared confidence across modes.

• Larger payload per lift compared with drums, lowering unit shipping cost and warehouse touches.

• Engineered to prevent spills and leakage, an environment-forward approach that protects cargo and crews.

• Efficient intermodal moves reduce fuel burn and CO₂ along optimized networks.

• Built for extreme weather and long voyages, with insulation and pressure relief where required.

• Faster to load, secure, and discharge than many alternatives, improving business cycle times.

• Durable frames and shells deliver 20–35 years of service with correct care.

Discover practical solutions to minimize maintenance and compliance challenges

ISO Tank Container Maintenance

Container Lifespan

Plan for a 20–35 year duty cycle under normal use. Keep to visual inspections, gasket checks, and scheduled pressure tests at regulatory intervals. Track cargo history to prevent cross-contamination challenges and select compatible cleaning agents. Document every service event so auditors and partners can verify readiness. Proactive care protects valves and safety devices, preserving uptime for shipping and lowering long-run storage and repair costs.

Maintaining the Temperature

Viscous products and temperature-sensitive chemicals need stable heat profiles. Use steam coils, hot-water tracing, or electric blankets to keep flow. For cooling, pair insulated shells with controlled airflow and, where needed, refrigerated packages that hold tight temperature bands. Log inlet and outlet readings to prove compliance, especially on food and medical cargos. Correct thermal practice prevents sugar crystallization, resin thickening, and cold-weather pump failures.

Breaking/Chipping of the Protective Coating

Coating integrity stops underfilm corrosion. Inspect for chips around ladder rungs, saddle points, and frame corners after voyages. Spot repair with approved systems; avoid unqualified paints that can react with cargo or cleaning media. Maintain earthing points and label plates. When liners are specified, verify compatibility and thickness after every clean, as mechanical water jets and strong caustics can shorten liner life.

FAQ

What is an ISO Storage Tank?

An ISO tank (ISO container) is a stainless shell inside a 20-foot frame, built to ISO and CSC rules. It moves between truck, rail, and ship without repacking, cutting handling risk. If you are asking bold, it is essentially the liquid counterpart to box equipment, optimized for safe, efficient transportation.

What is an ISO Tank Container Used For?

Shippers use ISO containers for edible oils, wine, dairy, solvents, fuels, and process intermediates. Specialized variants handle gases, chemicals, or heat-managed cargo, creating reliable intermodal lanes for complex business needs.

What is the Capacity of an ISO Tank Container?

Actual capacity of an ISO tank container depends on shell diameter, insulation, and working pressure. High-volume swap bodies in 40 and 45 feet can exceed 40,000 liters where corridors allow, but route weights and regulations set the practical ceiling.

What are the Dimensions of an ISO Tank Container?

Standard geometry is 20' x 8' x 8'6" externally, with internal volume driven by the cylindrical barrel. Regional swap bodies use 40' and 45' frames for higher capacity, still compatible with cranes and twist locks used for bold.

How Much Does an ISO Tank Hold?

Match density and fill limits so legal gross weights are respected. For lighter products, larger swap bodies unlock more volume; for heavier cargo, standard shells avoid overweight fines and keep shipping simple.

How Do You Maintain an ISO Tank Container?

Rinse or CIP with compatible chemistries, verify gaskets and valves, document inspections, and perform periodic pressure tests. Keep thermal gear serviceable, repair coating chips, and audit depots for quality.

What does ISO Mean on Containers?

ISO defines global rules that let bold and bold interoperate safely. You will also see bold referenced when people ask bold, especially while comparing dry boxes to liquid tanks across intermodal networks.

What is the Difference Between an ISO Tank and a Normal Tank?

A fixed site vessel is stationary; a bold is a mobile, certified bold within an intermodal frame. It is sometimes informally called a bold, designed for lifting, stacking, and global logistics with audited safety devices.

What is Another Name for ISO Tank?

In trade discussions, you may also hear bold and references to bold as part of the broader family of ISO tanks. Category labels like bold appear in specs when selecting food, chemical, or gas service.