Container marking

A container is a reusable transport equipment designed for container freight shipping to the point of destination by means of road, rail, and water transport.

A container can be reused if its loading and installation have been done correctly. Misuse can lead to it going out of service and damage of the goods. To prevent such situations from happening, every container is given a marking.

The current standard which deals with the coding, identification, and marking of containers is ISO 6346, dated 1996. The standards for international shipping containers are managed by the International Container Bureau (BIC).

A distinction is drawn between compulsory and optional marks. Optional marks can be assigned at the will of the owner for easy recognition of goods.

Compulsory marking must be used on all containers and is applied onto the door and other planes of the container (sidewalls, roof, bottom).

The container identification number consists of the:

owner code, consisting of three capital letters;
equipment category identifier — one of the capital letters – U, J, or Z;
serial number of six numeric digits;
check digit of one numeric digit.

The owner code must be unique and registered with the BIC (either directly or through a national representative of the organization).

The letter in the equipment category identifier stands for:

U - freight containers;
J - detachable freight container-related equipment;
Z - trailers and chassis.

The owner code and equipment category identifier can be grouped under one term, also known as an alpha prefix.

container marking

If the owner code is absent, the container cannot be identified.

The registration or serial number consists of six digits. If the number has fewer than six digits, zeros are added in the beginning of the number to make a six-digit number sequence.

The last digit in the container number – the check digit – is always a single-digit number. It is usually placed in a box to single it out from the rest of the numbers in the registration code.

The check digit is used to verify the accuracy of the owner code, the equipment category identifier, and the registration number. If the result number of the automatic checking procedure does not correspond to the number in the check digit – no transport or freight information system will be able to process the container.

The procedure has been introduced to ensure the correctness of input data of the international container shipping information systems.

The checking procedure is as follows: every letter is assigned an equivalent numerical value on the basis of its position in the alphabet, beginning with 10 for the Latin letter A (11 and its multipliers are omitted). The individual digits of the registration number keep their numeric value). Every number is multiplied by 2exponent, where the value of the exponent corresponds to the position of the digit in the registration number from 0 to 9, left to right (the first digit is multiplied by 1, the second – by 2, the third – by 4, the fourth – by 8, the fifth – by 16, the sixth – by 32, the seventh – by 64, the eighth – by 64, the ninth – by 256, and the tenth – by 512). The results are summed up, after that, divided by 11, and rounded down to zero (made a whole number). The whole number is multiplied by 11. The result is subtracted from the result of the initial calculations (summation). The final difference is the check digit.

If the final number is 10, the check digit becomes 0. The standard doesn’t recommend the use of serial numbers which produce a final difference of 10.

Containers also have a sized and type code.The latter includes four elements:

the first character represents the length (2 for 20’’, 4 for 40’’, 3 for 30’’, for specific sizes a letter code is used);
the second character represents the width and the height;
the third and the fourth character indicate the type of the container.

The code for the length of the container is shown in the following table:

Character	Container length
Character	mm	ft
1	2,991	10
2	6,058	20
3	9,125	30
4	12,192	40
5-9	Spare
A	7,15
B	7,315	24
C	7,43
D	7,45	24,6
E	7,82
F	8,1
G	12,5	41
H	13,106	43
K	13,6
L	13,716	45
M	14,63	48
N	14,935	49
P	16,154

The code for the height and width of the container:

Width,m	Character	Container height		Character for container width
Width,m	Character	mm	ft	> 2,438 m and <2,5 m	> 2,5 m
2,438	0	2,438	8
2,438	2	2,591	8’6	C	L
2,438	4	2,743	9	D	M
2,438	5	2,895	9’6	E	N
2,438	6	>2,895	>9’6	F	P
2,438	8	1,295	4’3
2,438	9	<1,219	<4

As the last two characters a group code can be used if the subgroup is not specified by the standard. The codes of container types are presented in the table.

General Code	Group Code	Type	Type Code	Characteristics
G	GP	Unventilated general purpose container	G0	Openings at both ends
			G1	Vents in upper part of cargo space
			G2	Openings at one or both ends + full openings on one or both sides
			G3	Openings at one or both ends + partial openings on one or both sides
			G4-G9	Spare
V	VH	General purpose container with ventilation	V0	Non-mechanical ventilation at the lower and upper parts of the cargo space
			V1	Spare
			V2	Mechanical ventilation installed in the container
			V3	Spare
			V4	Mechanical ventilation installed outside the container
			V5-V9	Spare
B	BU	Dry bulk containers, non-pressure resistant	B0	Closed
			B1	Airtight
			B2	Spare
		Container for dry bulk cargo pressure control	B3	Horizontal discharge, test pressure 150kPa
			B4	Horizontal discharge, test pressure 265kPa
			B5	Tipping discharge, test pressure 150kPa
			B6	Tipping discharge, test pressure 265kPa
			B7-B9	Spare
S	SN	Named cargo containers	S0	Livestock container
			S1	Automobile container
			S2	Living fish container
			S3-S9	Spare
R	RE	Thermal containers (refrigerated, refrigerated and heated, self/externally powered)	R0	Mechanically refrigerated
	RT		R1	Mechanically refrigerated and heated
	RS		R2	Mechanically refrigerated, self-powered
			R3	Mechanically refrigerated and heated, self-powered
			R4-R9	Undefined
H	HR	Thermal container (refrigerated and/or heated with removable equipment)	H0	Refrigerated or heated with removable equipment located externally; heat transfer coefficient 0.4W/(m2*K)
			H1	Refrigerated or heated with removable equipment located internally
			H2	Refrigerated or heated with removable equipment located externally; heat transfer coefficient 0.7W/(m2*K)
			H3-H4	Spare
	HI		H5	Insulated, heat transfer coefficient 0,4W/(m2*К)
			H6	Insulated, heat transfer coefficient 0,7W/(м2*К)
			H7-H9	Spare
U	UT	Open-top container	U0	Openings at one or both ends
			U1	Openings at one or both ends, removable roof
			U2	Openings at one or both ends + openings on one or both sides
			U3	Openings at one or both ends + openings on one or both sides + removable top members
			U4	Openings at one or both ends + openings on one or both sides + full openings on one side
			U5	Solid side and end walls (no doors)
			U6-U9	Spare
P	PL	Platform-container (with incomplete superstructure, removable walls, open and closed)	P0	Plain platform
	PF		P1	Platform with two complete, fixed end walls
	PF		P2	Platform with fixed posts and with removable top members
	PC		P3	Platform with folding complete end walls
	PC		P4	Platform with folding posts and with removable top members
	PS		P5	Platform open at the top and ends
			P6-P9	Spare
T	TN	Tank container for non-dangerous liquids	T0	Minimum pressure 45 kPa
			T1	Minimum pressure 150 kPa
			T2	Minimum pressure 265 kPa
	TD	Tank container for dangerous liquids	T3	Minimum pressure 150 kPa
			T4	Minimum pressure 265 kPa
			T5	Minimum pressure 400 kPa
			T6	Minimum pressure 600 kPa
	TG	Tank container for gasses	T7	Minimum pressure 910 kPa
			T8	Minimum pressure 2200 kPa
			T9	Minimum pressure to be assigned
A	AS	Air/surface container	A0

Optional mark includes country code, weight of the container, a symbol to denote containers for air freight transportation, a sign warning of overhead electrical danger, height of the container (for containers higher than 2.6m).

The country code consists of two capital letters of the Latin alphabet as stated in ISO 3166. The country implies the country of container registration, not the country of the owner or the shipping company that carries out the international transportations.

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