
Photo: Dr. Jean-Paul Rodrigue, 2012
Container Identification System
The container identification system is an ISO standard (ISO 6346)
composed of a sequence of letters and numbers. The above photo displays
this identification on the top right part of the container:
- Owner code. Consisting of three capital letters
that identifies the owner of the container. There is an international
agency that issues owner codes so that no single code is assigned
to more than one owner. In the above case the container belongs
to the American company Textainer, the world's largest container
leasing company with a fleet of 1.7 million containers. The great
majority of shipping and container leasing companies advertise their
logo on the container, so the owner is commonly easy to identify.
- Product group code. Appears right after the
owner code and consists of one capital letter, either U, J or Z;
U refers to a container, J refers to equipment that can be attached
to a container, such as a power unit and Z refers to a trailer or chassis
used to carry a container. Therefore, each mobile intermodal equipment
has its own identification code.
- Registration Number (or Serial Number). A sequence
of 6 digits where each container belonging to an owner has a unique
value. Therefore, each owner code can have up to 1 million containers.
- Check digit. This single digit is used to cross-verify
if the identification sequence is accurate. By convention it is
boxed to make sure it is separated and is standing out from the
registration number. Since terminal gates handle a large amount
of containers, there is always a risk that the identification sequence
was not correctly inputted. The standard procedure involves the
sequence to be remotely inputted by a video camera with the operator
entering the sequence manually in the information system or increasingly
that sequence being inputted automatically through optical character
recognition software. A numerical operation is performed on the
container identification sequence which results in a single digit
number, which is then compared with the check digit. If they match,
then the identification sequence is accurate (there is still a probability
for error, but it is very low).
- Size and type code. A sequence of 4 letter
or digits that commonly appear right under the container identification
sequence. Its purpose is to provide information about the dimensions
and the type of container. On the above photo, the first two numbers
45 indicate that the container is a 40 footer (4; commonly the
length of the container) of 9 feet 6 inches in height (5; high
cube). The remaining two elements of the sequence (G1) indicate
that it is a general purpose container. The most common container, a standard 40 footer, would have 42G1
as a sequence. 45R1 is the most common
sequence for a reefer (40 foot high cube). High cube 45 foot
containers are convenient for intermodal transportation in
Europe as they have the size that fits exactly 33 European
pallets of 1.2 by 0.8 meters.
The operational characteristics of the container are also commonly
displayed. They include the maximum gross weight which is the maximal
weight the loaded container can have, which is commonly around 30 metric
tons. The container weight (Tare) is also provided, a number which should
be between 4 to 10 metric tons. The payload is simply the gross minus
the tare weight, which is the maximum weight that can be loaded into
the container. Maximum cargo volume information is also provided since
cargo carried by container tends to "cube out" before it "weights out".