Container types — from dry container to reefer and tank
Not all containers are the same: here's how to tell the difference between dry, reefer, tank, open top and flat rack
When you stand on the dock and see a container being lifted by a crane most look alike: a rectangular steel box in one of a few standard sizes. But behind the uniform facade hide several different types built for very different goods. Being able to recognize the container type from a distance is part of the craft — it tells you something about how the container should be handled what equipment to use and what precautions apply.
§The dry container — the workhorse
The ordinary, closed steel container — dry container — is the most common and is used for general cargo, pallets and packaged goods that do not require special temperature or handling. It comes in standardized lengths, typically 20 and 40 feet, as well as higher versions (high cube). It is this type that most container cranes, reachstackers and chassis are equipped for, and it makes up the vast majority of the goods moved over a container terminal.
§Reefer – the refrigerated container
A reefer container is in practice a large insulated refrigerator with its own cooling unit. It is used for food medicine and other goods that must be kept within a specific temperature band — some reefer solutions can regulate from approximately -65 to +40 degrees depending on cargo and equipment. The container must have power all the way: from the ship's own reefer system from a generator on the chassis or from the terminal's reefer connection while it stands on the lot. If it loses power for too long the entire cargo can be destroyed.
§Tank container — liquids and gases
The tank container is a cylindrical tank in a standardized frame, built in corrosion-resistant material to transport liquid substances, chemicals, or gases — often including hazardous goods. The outer frame has the same dimensions and corner castings as a standard container so it can be handled with the same equipment, but the contents place different demands on control of valves, tightness, and labelling before it is moved.
§Open top and flat rack — when goods don't fit in the container
Some loads are too high, wide or heavy for a closed container. An open top container has a tarpaulin instead of a fixed roof so that high or irregular load can be loaded from above with a crane. A flat rack is even more open – it has neither roof nor side walls, only a base and end walls, and is used for wide or heavy cargo like machinery parts, vehicles or sections of wind turbine blades. Both types require extra care when securing and lifting because the load is not hidden and supported by an entire box.
| Container type | Typical use |
|---|---|
| Dry (dry container) | Common piece goods and pallets without special requirements |
| Reefer | Food, medicine and other temperature-sensitive goods |
| Tank container | Fluids, chemicals and gases, including dangerous goods |
| Open top | High or irregular load that must be loaded from above |
| Flat rack | Broad or heavy goods without sides and roof e.g. machinery and wind turbine parts |
§Why the type matters for you
When you can read the container type you immediately know more about what's required of you: should power and temperature be checked are extra eyes needed on securing or is it dangerous goods requiring special marking and handling? Seeing the difference in types before you even touch the container is the first step to handling it correctly — and to spotting if something's wrong before it becomes a problem.
“A container is not just a box — it is built for a particular type of load and it will tell you if you know what to look for.”