An intermodal container or freight container (commonly shipping container) is a reusable transport and storage unit for moving products and raw materials between locations or countries; the terms container or box may be used on their own within the context of shipping. Containers manufactured to ISO specifications may be referred to as ISO containers and the term high-cube container is used for units that are taller than normal. There are approximately seventeen million intermodal containers in the world and a large proportion of the world’s long distance freight generated by international trade is transported inside shipping containers (as opposed to break bulk cargo).
The containerization system developed from a design of an 8-foot (2.438 m) cube units used by the United States’ military and later standardised by extension to 10-foot (3.05 m), 20-foot (6.10 m), and 40-foot (12.19 m) lengths. Longer, higher and wider variants are now in general use in various places.
Container variants are available for many different cargo types. Non-container methods of transport include bulk cargo, break bulk cargo and tankers/oil tankers used for liquids. For air freight the alternative and lighter IATA defined Unit Load Device is used.
A typical container has doors fitted at one end, and is constructed of corrugated weathering steel. Containers were originally 8 feet (2.44 m) wide by 8 feet (2.44 m) high, and either a nominal 20 feet (6.10 m) or 40 feet (12.19 m) long. They could be stacked up to seven units high.
Taller units have been introduced, including ‘hi-cube’ or ‘high-cube’ units at 9 feet 6 inches (2.90 m) and 10 feet 6 inches (3.20 m) high.
The United States often uses longer units at 48 ft (14.63 m) and 53 ft (16.15 m). Some rare European containers are often about 2 inches wider at 2.5 m (8 ft 2.4 in) to accommodate Euro-pallets. Australian RACE containers are also slightly wider to accommodate Australia Standard Pallets.
Lighter swap body units use the same mounting fixings as Intermodal containers, but have folding legs under their frame so that they can be moved between trucks without using a crane.
Each container is allocated a standardized ISO 6346 reporting mark (ownership code), four characters long ending in either U, J or Z, followed by six numbers and a check digit.
Container capacity is often expressed in twenty-foot equivalent units (TEU, or sometimes teu). An equivalent unit is a measure of containerized cargo capacity equal to one standard 20 ft (length) × 8 ft (width) container. As this is an approximate measure, the height of the box is not considered; for example, the 9 ft 6 in (2.90 m) high cube and the 4-foot-3-inch (1.30 m) half height 20-foot (6.10 m) containers are also called one TEU. Similarly, the 45 ft (13.72 m) containers are also commonly designated as two TEU, although they are 45 and not 40 feet (12.19 m) long. Two TEU are equivalent to one forty-foot equivalent unit (FEU).
Variations on the standard container exist for use with different cargoes including Refrigerated container units for perishable goods, tanks in a frame for bulk liquids, open top units for top loading and collapsable versions. Containerised coal carriers, and ‘bin-liners’ (containers designed for the efficient road/rail transportation of rubbish from cities to recycling and dump sites) are used in Europe.
* Collapsible ISO
* Flushfolding flat-rack containers for heavy and bulky semi-finished goods, out of gauge cargo
* Gas bottle
* General purpose dry van for boxes, cartons, cases, sacks, bales, pallets, drums in standard, high or half height
* High cube palletwide containers for europallet compatibility
* Insulated shipping container
* Refrigerated containers for perishable goods
* Open top bulktainers for bulk minerals, heavy machinery
* Open side for loading oversize pallet
* Platform or bolster for barrels and drums, crates, cable drums, out of gauge cargo, machinery, and processed timber
* Rolling floor for difficult to handle cargo
* Tank containers for bulk liquids and dangerous goods
* Ventilated containers for organic products requiring ventilation