What are International Shipping Container Standards

Shipping Container Standards

What ISO #6346 stands for?

If you are deciding on a container home it is important to know what are International Shipping Container Standards. ISO #6346 standard describes the identification (ID) of shipping containers including their size, owner, category, serial number, type and some other important characteristics. Some call it Container Identification Number (CIN). All commercial shipping containers are registered with BIC (Bureau International des Containers).  In accordance with relevant ISO standards a unique number is assigned to each container. The BIC registers are available online so everybody can verify ID of a given module.

Shipping Container Owner Code

ISO 6346 Identification Standard for shipping containers



Owner Code

is a 3-letters word (here ABC) unique to the company owning the unit. Note that containers can be operated by a company leasing them from an owner and this fact wouldn’t be recorded in the ISO ID).


“U” (Freight Container)

is the most popular category of containers, and from the point of view of containers houses, the only one of interest. Others are corresponding: J (Detachable Freight Container Equipment), R (Refrigerated Container), and Z (Trailers and Chassis).


Serial Number:

It is a unique 6-digits number assigned by BIC to the particular owner (Note that it’s NOT the container’s manufacturer serial number).
Check digit: It’s a single-digit number providing means to validate the owner’s code and serial number (needed mainly for electronic identification).


Size/Type code:

It’s a 4-digit alphanumeric number.

The first character represents the container’s length (the most common are 1 for 10ft, 2 for 20ft, and 4 for 40ft. The relevant ISO list is much longer and includes also less popular standards like 45ft symbolized by “L” etc..).

The Second character represents the container’s height and width. The most common sizes, correspondingly 20ft and 40ft containers will be marked as follows:


The third and Fourth characters represent the type of the container and some of its characteristics. The most popular are General

Purpose (GP) containers marked as G0 (w/one or two opening ends) and G1 (G0 but w/passive vents at the top). The full list is quite long and will include also codes like Bx (for Dry Bulk Cargo containers), Vx (for ventilated containers), Rx (for refrigerated or heated containers), Px (for collapsible containers), etc. The “x” (digit from 1 to 9) is used for a more detailed description.

The ID (CIN)

the number is painted on all sides of the container is large, well-visible characters so it is easy to read it even from afar. It is also permanently stamped on the container’s frame post (interior) and marked on the CSC plate (see below).

For details go to: BIC Codes

CSC Plate: What are International Shipping Container Standards

The CSC plate includes information required by the International Convention for Safe Containers (CSC). It’s sort of “container’s passport” holding information crucial for the safety of operators, workers, transport equipment etc…

International Convention for Safe Containers

Example of the CSC plate (Source: BIC)

Each container used for international transport must have attached a valid CSC plate. The CSC plate must display:

  • The country of approval and approval reference
  • Manufacturing date (month and year)
  • Container’s ID Number (assigned by BIC to the owner)
  • Specifications (all in kg and pounds (lbs)) including:
    – Maximum Gross Weight

It’s the maximum weight of the given container loaded with cargo.

– Maximum Stacking Weight

During overseas transport, containers are piled on top of each other, so it is crucial that each of them can withstand the load of all superimposed containers. The Maximum Stacking Weight specifies the limit.

– (Transverse) Racking Test Load Value

In the Transverse Racking Load Test, the external lateral force is applied to the container’s top-corner fitting to evaluate its resistance to sideways pressure and stretching.

Transverse Racking Test Load

Transverse Racking Test Load (Source: containerhandbuch.de )

f) Inspection date

The container’s inspection must be performed before it leaves the factory door. The initial one is valid for the next 5 years. At the expiration, the container must be recertified, and the new expiration date stamped on the CSC plate. Any substantial mechanical damage to the container nullifies the validity of the CSC certification and if repaired, it must be recertified once again.

Containers can be also inspected in a “continuous” way by in-service inspectors. The CSC plate must then include information that the container was Approved for the Continuous Examination Program (ACEP), as well as the name of the country that granted ACEP approval, a year when it was granted, and the Registration Number.

New CSC plates also include additional information:

g) Manufacturer (name, container’s model and serial numbers)

h) Owner’s name and address (already encoded in container’s mandatory ISO ID)

i) Timber treatment information

It displays the name of the chemical product used for the treatment of wood (or wood-derived products) as well as period of its validity (effectiveness). Most of these products belong to the class of insecticides and are used to prevent the spread of local species to other geographical regions. Their secondary effect is the protection of plywood floors from decaying.

In order to withstand years of exposure to an “aggressive” environment (sun, UV, salty moisture and water, freezing temperatures, winds, etc.) without fading or corroding, the CSC plates are typically made from anodized aluminum. They are bolted to the exterior of the container’s door (usually the left one).

Both, the ID (CIN) number and valid CSC plate are necessary in order to use cargo shipping containers for the transport of goods oversea (ships) and land (trucks, rail) without any restrictions. We hope that you learned what are International Shipping Container Standards and to find out more about legal issues click here!

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