Everything About ISO Cargo Shipping Containers

History of ISO Shipping Containers

What are ISO Shipping Containers made from?

What are the characteristics of an ISO Shipping Container?

History of ISO Shipping Containers

The shipping container has only been around for the last 50 years. The advent of this method of modular standard containerization of goods revolutionized the transportation of goods and ultimately the international export market as turnaround time, theft, damage to goods and costs all went down.  Until 1956 goods packed in bales, sacks or barrels were individually transferred from the vehicle to the waiting cargo ship. This was manual work carried out by “longshoremen” using pulleys, cargo hooks and a significant labor force. An average ship had 200, 000 individual pieces of cargo and it would take around a week to load and unload.


History credits Malcolm McLean with the development of the shipping container. By the 1950’s McLean had developed a large haulage business on the East Coast of the USA but had never forgotten the days of being a driver waiting for a whole day for goods to be loaded and unloaded at the port of New Jersey. He patented a container with reinforced corner posts that could be craned off a truck chassis and had integral strength for stacking. McLean was so confident in the potential of this modular cargo he took a loan for $42m and purchased the Pan-Atlantic Steamship Company with docking rights so that he could modify cargo ships to use his new containers.  He was forced to choose between haulage and shipping by the Interstate Commerce Act and so he focused on redeveloping the shipping firm and renamed it Sea-Land.

In April 1956 the modified oil tanker owned by Sea-Land ‘Ideal X’ sailed from New Jersey to Houston carrying 58 of the new containers.  Meanwhile on the West Coast of the USA the Matson Navigation Company decided to   invest in container technology. They took a different view and while McLean used   33 foot long containers, since these were the limited length permitted for a truck chassis the Matson company chose 24 foot. They were importing tinned goods from Hawaii and considered weight to be an issue, thus choosing a smaller container.  In 1958 the first Matson container ship set sail from San Francisco. Since there were specific docking requirements, namely large cranes, containerization required investment. The New York Harbour Authority realized this need and the potential of containerization and so built the first container port 'Port Elizabeth' in New Jersey in 1962. The Port of Oakland in California also realized that containerization would revolutionize trade with Asia and would protect the declining industry and so invested $600k in new facilities in 1969. 

The advent of containerization had hit the longshoremen hard. In 1960 a new agreement was reached between the dockside unions and shipping companies where the companies could bring in new machinery but a large pension fund was set up for longshoremen and they were given reduced working hours. This modularization of cargo reduced the time required to load and unload, it also reduced the number of longshoremen required, which resulted in the strike of 1971-72. Longshore jobs were allocated on a rota basis by the unions but containerization saw the needs for specialist crane operators thus the ports wanted to hire staff on a permanent contract. The shipping owners won their rights to employ the specialist staff and the containerization of shipping continued to move forward  .

The next step was to standardize the containers. At the time Matson’s on the west coast were using 24 foot containers and Sea-Land on the east were using 35 foot containers. The military were interested in containers but in a time of war the varied sizes would not be efficient. The Government was therefore pushing for standardization as were the freight companies who wanted to invest in containerization.  McLean owned the patent on the corner posts that were so vital to the strength and stacking of the containers and it was his release of this patent that allowed the ISO standardization to take place  .  

In 1969 Richard F Gibney, working at Shipbuilding and Shipping Record in the UK, simplified the statistics involved with comparing differing container sizes he coined the phrase Twenty Foot Equivalent (TEU) and this is the term that is still used to describe containers.

What are ISO shipping containers made from?

A typical ISO shipping container is made from a ‘weathering steel’ as specified within BS EN 10025-5:2004.  This is commonly known as Cor-ten’ steel.  Cor-ten steel is a corrosion resistant steel that is used within many industries where exposed steel sections are necessary,  e.g. building panels, facades and sculptures.

‘Weathering steels are specified in BS EN 10 155:1993 (superseded by BS EN 10025-5:2004) and within this category Cor-ten is a well known proprietary grade.  These steels have properties comparable with those of Grade S355 steels to BS EN 10 025’.



What are the characteristics of an ISO shipping container?

Shipping Container Specifications for the most common ISO Standard Shipping Containers:

  • External of a stand. ISO shipping container: 8' wide (2.44m) x 8' 6". (2.6m.) high,  and the usual lengths are 20' (6.1 m) and 40' (12.2 m).
  • Internal of a stand. ISO shipping container: 7' 10" (2.353 m) wide, 7' 8.625" (2.388 m) high, and 19' 4.25" (5.899 m) or 39' 5.375" (12.024 m) long.

Characteristics and Components of a standard ISO shipping container:

  1. Monocoque body
  2. Corner Castings
  3. Steel corrugated sheet sidewalls, roof, and back panel
  4. All-welded-steel, continuously
  5. Purin reinforced Plywood Floors
  6. Forklift pockets
  7. Grappler pockets
  8. Gooseneck tunnel

ISO Standard 40' Low Cube Shipping Container Drawing


The shipping container floors are made of planking or plywood wood, which is very strong and resilient, does not dent, and may be easily replaced during repairs. The floors also have a strong friction surface, which is important for cargo securing. Most containers are sprayed for insects because when lumber is used, it must comply with the quarantine regulations in most countries.

The forklift pockets of standard ISO steel shipping containers are easily visible and allow handling of empty shipping containers with forklift trucks. Forklift pockets are installed only in 20' x 8’ x 8’ standard ISO steel shipping containers and are arranged parallel to the center of the container in the bottom side rails. The 40' standard ISO steel shipping containers do not have forklift pockets. This is due to the fact that the location of the pockets are relatively close together and such large containers would be difficult to balance.

Gooseneck tunnel of standard ISO steel shipping containers: Many 40' containers have a recess in the floor at the front end which serves to center the containers on so-called gooseneck chassis.

Grappler pockets of standard ISO steel shipping containers: Most all shipping containers are handled by top spreaders using what’s called corner fittings or corner castings. Also, some containers have grappler pockets. These were originally installed for hanging garments.

Additional specifications on steel shipping container:

  1. Racking/Shear Load of the shipping container (corner posts) 16,000 lb
  2. Side Wall Lateral Load of the shipping container 235 psf
  3. End Wall Lateral Load of the shipping container 366psf
  4. Racking/Shear Load of the shipping container 33,500 lb
  5. Stacking/ Axil Load of the shipping container 210,000 lb
  6. Roof Load of the shipping container 300psf
  7. Floor Load of the shipping container 100 psf