Freight Containers Classification

The pattern of cargo reception and shipment has changed with the use of the freight container – container, box or LO/LO (lift on/lift off). The use of containers, which started more than 40 years ago, in intercontinental traffic is now available in most seaports worldwide.

In the 1960’s, many seaports either had inadequate container facility or none at all. Consequently, export shipments often relied on conventional (break-bulk) vessels. The cargoes were placed alongside a vessel for hoisting on board. The stevedores (longshoremen) were often employed to carry cargoes on and off the vessel. The loading and unloading of vessels consumed too much time, which caused dockside bottlenecks and delayed shipments. With the increased use of containers, the congestion was decentralized. The problem of congestion was transferred from the docks or piers to the container freight stations or terminals.

ISO Freight Containers

The acronym ISO stands for the International Organization for Standardization, with headquarters in Geneva, Switzerland. The ISO freight container refers to a container complying with the ISO container standards in existence at the time of its manufacture.

Container Classifications

Containers are available in configurations to take almost every kind of cargo and mode of transportation (ocean, air, road, and rail).

Containers for Intercontinental Use

In terms of the type of cargo for which the containers are mainly intended, they are classified as general cargo container and specific cargo container.

â—† General Cargo Container

(1) General purpose (dry cargo) container

It is suitable for the widest varieties of cargo. It is fully enclosed and weatherproof, having rigid walls, roof and floor, with at least one of its walls, either end wall (end loading) or side wall (side loading), equipped with doors.

dry cargo container

(2) Specific purpose container

It is used to facilitate the packing (loading) and emptying (unloading) of container other than by means of doors at one side of the container, and for other specific purposes like ventilation.

Closed ventilated containerIt is used for the carriage of cargo, such as hides, that cannot stand excessive moisture. It is similar to the dry cargo container with specially designed natural or mechanical (forced) ventilation.
Open top containerIt is similar to the dry cargo container except that it has no rigid roof, but has a movable or removable cover (e.g. a cover made of canvas, plastic or reinforced plastic material) supported on movable or removable roof bows. The open top container is used for machinery, sheet glass, and other heavy, bulky or long objects.
Platform (flat rack)It does not have a superstructure, that is, rigid side walls and load- carrying structures. The term load refers to static/dynamic form of load (not cargo load) or forces arising out of the lifting, handling, securement and transporting of container. It is equipped with top and bottom corner fittings. The corner fittings provide means of supporting, stacking, handling and securing the container. The flat rack is used for machinery, lumber, and other heavy or large objects.
Platform based containers open sided

â—† Specific Cargo Container

(1) Thermal container (reefer)

It has insulated walls, doors, roof, and floor, which limit the range of temperature loss or gain. It is used for perishable goods like meat, fruits and vegetables.

Insulated containerIt does not use any device for cooling and/or heating.
Refrigerated container (with expendable refrigerant)It uses dry ice or liquefied gases. It does not require external power supply or fuel supply.
Mechanically refrigerated containerIt uses a refrigerating appliance, that is, the mechanical compressor or absorption unit.
Heated containerIt uses the heater, that is, a heat-producing appliance.
Refrigerated and heated containerIt uses the refrigerating appliance (mechanical or expendable refrigerant) and heater.

(2) Tank container

It is used for the carriage of bulk gases and liquids like chemicals.

(3) Dry bulk container

It is used for the carriage of dry solids in bulk without packaging, such as grains and dry chemicals. It consists of a cargo-carrying structure firmly secured within the intercontinental container framework.

(4) Named cargo types

It consists of various types of containers, such as automobile (car) containers and livestock (cattle and poultry) containers.

Unit Load Device (ULD)

The unit load device (ULD) is the air equivalent of the ISO container. Due to its unique shape resembling an igloo, the ULD is sometimes called the igloo (or iglu).

The air mode containers mainly are of the IATA (International Air Transport Association) types. The popular sizes of ULD include the IATA Type:

IATA Type ULD
8 : lower deck container	60.4″ x 61.5″ x 64.0″
5 : lower deck container	88.0″ x 125.0″ x 64.0″
3 : main deck container	88.0″ x 125.0″ x 86.0″