An intermodal container is a standardized reusable steel box. They are used to store
and move materials and products in the global containerized intermodal freight transport
system efficiently and securely. "Intermodal" indicates 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 to 56 feet and heights from 8 feet to 9 feet 6 inches. There are about 17 million
intermodal containers in the world of varying types to suit different cargoes.
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 tank cars, tank trucks or oil
tankers used for liquids or gases.
History
The standardised steel shipping container has its origins in the 1950s when commercial
shipping operators and the United States military started developing such units. Shipping owner
Malcom McLean worked with engineer Keith Tantlinger to develop the modern intermodal container.
The logistics method employing these was named Container Express and was abbreviated ConEx.
That abbreviation evolved into a word within the American English lexicon.
ISO standards for containers were published between 1968 and 1970 by the International
Maritime Organization. These standards allow for more consistent loading, transporting,
and unloading of goods in ports throughout the world, thus saving time and resources.
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".
Description A typical container has doors fitted at one
end, and is made of corrugated weathering steel. Containers were originally 8-foot wide
by 8-foot high, and either a nominal 20-foot or 40-foot long. They could be stacked up
to seven units high. At each of the eight corners are castings with openings for twistlock
fasteners. The standard height is now 8 ft 6 in.
Taller units have been introduced, including "hi-cube" or "high-cube" units at 9 feet
6 inches and 10 feet 6 inches high. The United States and Canada often use longer
units at 48 ft and 53 ft. The "pallet wide" containers are about 2 inches
wider than standard containers to accommodate Euro-pallets, common in Europe. These containers
feature an internal width of 2,440 mm for easy loading of two 1,200 mm long pallets
side by side – many sea shipping providers in Europe allow these as overhangs on standard
containers are sufficient and they fit in the usual interlock spaces. Australian RACE
containers are also slightly wider to accommodate Australia Standard Pallets. Especially the
45 ft 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 European Intermodal
Loading Unit initiative. Container capacity is often expressed in twenty-foot
equivalent units. An equivalent unit is a measure of containerized cargo capacity equal
to one standard 20 ft × 8 ft container. As this is an approximate measure, the height
of the box is not considered; for example, the 9 ft 6 in high cube and the 4-foot-3-inch
half height 20-foot containers are also called one TEU. Similarly, the 45 ft containers
are also commonly designated as two TEU, although they are 45 feet and not 40 feet long. Two
TEU are equivalent to one forty-foot equivalent unit.
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. The containers flex during transport.
Types
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" are used in Europe. Container types include:
Collapsible ISO Gas bottle
Generator 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 Swapbody
Tank container for bulk liquids and dangerous goods
Ventilated containers for organic products requiring ventilation
Garmentainers for shipping garments on hangers Flushfolding flat-rack containers for heavy
and bulky semi-finished goods, out of gauge cargo. Empty flat-racks can be stacked or
shipped sideways in an ISO container. Specifications
Weights and dimensions of some common types of containers. Values vary slightly from manufacturer
to manufacturer. Security
Intermodal containers can be the target of break-ins and burglary when left unattended
since they often contain valuables. In these cases, a security system consisting of a motion
detector and panel can trigger a siren, strobe, or light to deter intruders. Many panels have
wireless communication so that security guards can be alerted if an alarm is triggered.
Motion detectors can be used as a security method. However, many break-ins occur by criminals
cutting through a wall of the container, so the obstructed sensor becomes useless. Tomographic
motion detectors work well in intermodal containers because they do not require a line of sight
to detect motion. The entire container is covered by a volumetric sensing mesh that
is not blocked by equipment or inventory. Tomographic motion detection is not prone
to misdetection due to dirt buildup as is the case for beams and infrared sensors.
Stacking containers
At stacking load-bearing locations, 40-foot containers are the standard unit length, and
45 ft, 48 ft, and 53 ft all stack at the 40 ft coupling width. Other units can be
stacked on top of 20 ft units only if there are two in a row and 20 ft units cannot be
stacked on top of 40 ft units, or any other larger container.
The coupling holes are all female and it takes a double male twist lock to securely mate
container stacks together. Larger containers
53 foot container
Introduced in 1989, the 53 ft shipping container is considered a High Cube container in that
it is 9 ft 6 in tall on the exterior. It is 1 ft taller than standard height containers.
It is 8 ft 6 in wide which makes it 6 in wider than standard containers. The bigger
boxes have 60% more capacity than standard 40-foot containers enabling shippers to consolidate
more cargo into fewer containers. The original domestic 53-foot box OTR containers were introduced
in 1989, but in November 2007 the first 53 foot ocean containers were introduced. All
new, reinforced 53-foot boxes are built specifically for international trade and designed to withstand
ocean voyages. According to APL, 53-foot containers could become the transport method of choice
for customers moving cargo. In March 2013 APL stated that it "no longer offers vessel
space for 53-foot ocean containers in its trans-Pacific services. It has struggled to
find sufficient amount of U.S. export cargo for them, while revenue on the eastbound leg
has not been sufficient to cover the costs of repositioning empties back to Asia."
Reporting mark
Each container is allocated a standardized ISO 6346 reporting mark, four characters long
ending in either U, J or Z, followed by six numbers and a check digit. The ownership code
for intermodal containers is issued by the Bureau International des Containers et du
Transport Intermodal, 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 and
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 initiative. This showed advantages for intermodal transport of containers
and swap bodies. This led 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 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.
Handling and transport
Containers can be transported by container ship, semi-trailer truck, sidelifter 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. Rail
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 through which high-cube containers cannot pass, 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 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 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 above the track and 1,435 mm does not provide adequate stability to run
double-stacked containers on flat cars. Ship
Each year an estimated 10,000 shipping containers fall into the sea; of these 10% are expected
to contain chemicals toxic to marine life. Securing loads in intermodal containers
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.
Non-shipping uses
Containers have been used for other purposes at the end of their voyaging lives. Permanent
or semi-permanent placement for storage is common. A container has 8,000 lb of steel,
which takes 8,000 kWh of energy to melt down. Repurposing used shipping containers is increasingly
a practical solution to both social and ecological problems.
Shipping container architecture employs 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 traditional looking home. They have also been used to make temporary
shops, cafes, and computer datacenters, e.g., the Sun Modular Datacenter.
The Russian 3M-54 Klub surface-to-surface missile can be launched from a platform based
on shipping containers, and transported as one.
Intermodal containers are not constructed for conversion to underground bunkers, as
the walls cannot sustain much lateral pressure, and will collapse. Also, the wooden floor
of many used containers could contain some fumigation residues, rendering them unsuitable
as confined spaces, such as for prison cells or bunkers. Cleaning or replacing the timber
floor can make these used containers habitable, with proper attention to such essential issues
as ventilation and insulation. See also
References
Further reading George, Rose. Ninety Percent of Everything:
Inside Shipping, the Invisible Industry That Puts Clothes on Your Back, Gas in Your Car,
and Food on Your Plate, describes typical sea voyage excerpt and text search
International Organization for Standardization, Freight containers, Volume 34 of ISO standards
handbook, International Organization for Standardization, 4th edition, 2006. ISBN 92-67-10426-8
Levinson, Marc. The Box: How the Shipping Container Made the World Smaller and the World
Economy Bigger, Princeton, N.J. : Princeton University Press, 2006. ISBN 0-691-12324-1
excerpt and text search Donovan, Arthur & Bonney, Joseph "The Box
That Changed The World", East Windsor, New Jersey, Commonwealth Business Media, 2006
ISBN 978-1-891131-95-0 External links
International Convention for Safe Containers