An intermodal container (also container, freight container, ISO container , shipping container, hi-cube container, box, conex box and sea can) is a standardized reusable steel box used for the safe, efficient and secure storage and movement of materials and products within a global containerized intermodal freight transport system. "Intermodal" implies that the container can be moved from one mode of transport to another without unloading and reloading the contents of the container. Lengths of containers, which each have a unique ISO 6346 reporting mark, vary from 8-foot (2.438 m) to 56-foot (17.07 m) and heights from 8-foot (2.438 m) to 9 feet 6 inches (2.9 m). There are approximately seventeen million intermodal containers in the world of varying types to suit different cargoes.[1] Aggregate container capacity is often expressed in twenty-foot equivalent units (TEU / teu) which is a unit of capacity equal to one standard 20 × 8 ft (6.10 × 2.44 m) (length × width) container.
For air freight the alternative and lighter IATA-defined Unit Load Device is used. Non-container methods of transport include bulk cargo, break bulk cargo and tankers/oil tankers used for liquids.
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The standardised steel shipping container has its origins in the 1950's when commercial shipping operators and the US military started developing such units.
ISO Standards for containers were published between 1968 and 1970.
The International Convention for Safe Containers is a 1972 regulation by the Inter-governmental Maritime Consultative Organization on the safe handling and transport of containers. It decrees that every container travelling internationally is supplied with a "CSC-Plate".[2][3]
A typical container has doors fitted at one end, and is constructed of corrugated weathering steel.[4] Containers were originally 8 feet (2.44 m) wide by 8 feet (2.44 m) high, and either a nominal 20 feet (6.1 m) or 40 feet (12.19 m) long. They could be stacked up to seven units high. At each of the eight corners are castings with openings for twistlock fasteners.
Taller units have been introduced, including 'hi-cube' or 'high-cube' units at 9 feet 6 inches (2.9 m) and 10 feet 6 inches (3.2 m) high.[5] The United States often uses longer units at 48 ft (14.63 m) and 53 ft (16.15 m).
The "pallet wide" containers are about 2 inches (5 cm) wider than standard containers to accommodate for Euro-pallets common in Europe[6] These containers feature an internal width of 2440 mm for easy loading of two 1200 mm long pallets side by side - many sea shipping providers in Europe allow these as overhangs on standard containers and are sufficient to fit them in the usual interlock spaces. Australian RACE containers are also slightly wider to accommodate Australia Standard Pallets. Especially the 45ft pallet-wide high-cube shortsea container has gained wider acceptance as these containers can replace the 13.6 m swap bodies that are common for truck transport in Europe - the EU has started a standardization for pallet wide containerization in the EILU (European Intermodal Loading Unit) initiative.[7]
Swap body units use many of 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. They are generally lighter in weight.[8][9] The containers flex during transport.[10]
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 × 8 ft (6.10 × 2.44 m) (length × width) container. As this is an approximate measure, the height of the box is not considered; for example, the 9 ft 6 in (2.9 m) high cube and the 4-foot-3-inch (1.3 m) half height 20-foot (6.1 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).[11]
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 collapsible 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.
Weights and dimensions of the some common types of containers.[13] [16] [17] Values vary slightly from manufacturer to manufacturer.
20′ container | 40′ container | 40′ high-cube container | 45′ high-cube container | ||||||
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imperial | metric | imperial | metric | imperial | metric | imperial | metric | ||
external dimensions |
length | 19′ 10 1⁄2″ | 6.058 m | 40′ 0″ | 12.192 m | 40′ 0″ | 12.192 m | 45′ 0″ | 13.716 m |
width | 8′ 0″ | 2.438 m | 8′ 0″ | 2.438 m | 8′ 0″ | 2.438 m | 8′ 0″ | 2.438 m | |
height | 8′ 6″ | 2.591 m | 8′ 6″ | 2.591 m | 9′ 6″ | 2.896 m | 9′ 6″ | 2.896 m | |
interior dimensions |
length | 18′ 8 13⁄16″ | 5.710 m | 39′ 5 45⁄64″ | 12.032 m | 39′ 4″ | 12.000 m | 44′ 4″ | 13.556 m |
width | 7′ 8 19⁄32″ | 2.352 m | 7′ 8 19⁄32″ | 2.352 m | 7′ 7″ | 2.311 m | 7′ 8 19⁄32″ | 2.352 m | |
height | 7′ 9 57⁄64″ | 2.385 m | 7′ 9 57⁄64″ | 2.385 m | 8′ 9″ | 2.650 m | 8′ 9 15⁄16″ | 2.698 m | |
door aperture | width | 7′ 8 ⅛″ | 2.343 m | 7′ 8 ⅛″ | 2.343 m | 7′ 6" | 2.280 m | 7′ 8 ⅛″ | 2.343 m |
height | 7′ 5 ¾″ | 2.280 m | 7′ 5 ¾″ | 2.280 m | 8′ 5″ | 2.560 m | 8′ 5 49⁄64″ | 2.585 m | |
volume | 1,169 ft³ | 33.1 m³ | 2,385 ft³ | 67.5 m³ | 2,660 ft³ | 75.3 m³ | 3,040 ft³ | 86.1 m³ | |
maximum gross mass |
66,139 lb | 30,400 kg | 66,139 lb | 30,400 kg | 68,008 lb | 30,848 kg | 66,139 lb | 30,400 kg | |
empty weight | 4,850 lb | 2,200 kg | 8,380 lb | 3,800 kg | 8,598 lb | 3,900 kg | 10,580 lb | 4,800 kg | |
net load | 61,289 lb | 28,200 kg | 57,759 lb | 26,600 kg | 58,598 lb | 26,580 kg | 55,559 lb | 25,600 kg |
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.[18] The ownership code for intermodal containers is issued by the Bureau International des Containers (38, rue des Blancs Manteaux · FR75004 Paris), hence the name BIC-Code for the intermodal container reporting mark. So far there exist only four-letter BIC-Codes ending in "U".
The placement and registration of BIC Codes is standardized by the commissions TC104 und TC122 in the JTC1 of the ISO which are dominated by shipping companies. Shipping containers are labelled with a series of identification codes that includes the manufacturer code, the ownership code, usage classification code, UN placard for hazardous goods and reference codes for additional transport control and security.
Following the extended usage of pallet-wide containers in Europe the EU had started the Intermodal Loading Unit (ILU) initiative. This showed advantages for intermodal transport of containers and swap bodies. This lead to the introduction of ILU-Codes defined by the standard EN 13044 which has the same format as the earlier BIC-Codes. The International Container Office BIC agreed to only issue ownership codes ending with U, J or Z. The new allocation office of the UIRR (International Union of Combined Road-Rail Transport Companies) agreed to only issue ownership reporting marks for swap bodies ending with A, B, C, D or K - companies having a BIC-Code ending with U can allocate an ILU-Code ending with K having the same preceding digits. Since July 2011 the new ILU codes can be registered, beginning with July 2014 all intermodal ISO containers and intermodal swap bodies must have an ownership code and by July 2019 all of them must bear a standard-conforming placard.[19]
Containers can be transported by container ship, semi-trailer truck and freight trains as part of a single journey without unpacking and they are transferred between modes by container cranes at container terminals. Units can be secured during handling and in transit using "twistlock" points located at each corner of the container. Every container has a unique BIC code painted on the outside for identification and tracking, and is capable of carrying up to 20–25 tonnes. Costs for transport are calculated in twenty-foot equivalent units (TEU).
When carried by rail, containers may be carried on flatcars or well cars. The latter are specially designed for container transport, and can accommodate double-stacked containers. However the loading gauge of a rail system may restrict the modes and types of container shipment. The smaller loading gauges often found in European railroads will only accommodate single-stacked containers. In some countries, such as the United Kingdom, there are sections of the rail network which high-cube containers cannot pass through, or can pass through only on well cars. On the other hand, Indian Railways runs double-stacked containers on flatcars under 25 kV overhead electrical wires. In order to do this, the wire must be at least 7.45 metres (24 ft 5 in) above the track, but IR is able to do so because of its large loading gauge and the extra stability provided by its 1,676 mm (5 ft 6 in) broad gauge track. China Railways also runs double-stacked containers under overhead wires, but must use well cars to do so since the wires are only 6.6 metres (21 ft 8 in) above the track and 1,435 mm (4 ft 8 1⁄2 in) (standard gauge) does not provide adequate stability to run double-stacked containers on flat cars .[20]
There are many established methods and materials available to stabilize and secure cargo in intermodal containers. Conventional restraint methods and materials such as steel strapping and wood blocking & bracing have been around for decades and are still widely used. Polyester strapping and lashing, synthetic webbings are also common today. Dunnage Bags, also known as "air bags" are used to help keep unit loads in place.
Flexi-bags can also be directly loaded, stacked in food-grade containers. Indeed their standard shape fills the entire ground surface of a 20'ISO container.
Containers have been used for other purposes at the end of their voyaging life, in the interest of saving energy and resources. A container has 8,000 lb (3,629 kg) of steel which takes 8,000 kWh (28,800 MJ) of energy to melt down. Repurposing used shipping containers is increasingly a real solution to both social and ecological problems.
Shipping container architecture is employing used shipping containers as the main framing of modular home designs, where the steel may be an integrated part of the design, or be camouflaged into a very traditional looking home. There's even a company that repurposes shipping containers for the commercial sector for use as immersive branding environments.
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