April 19, 2021
Shipping containers are everywhere. They’re on ships, trains, and trucks transporting goods all over the world, used to store business and personal items, converted into homes and hotels, and modified for rental storage facilities.
Constructing massive amounts of these huge steel boxes capable of withstanding harsh weather and environmental hazards is no easy task. This blog will discuss the when, where, and how of shipping container construction.
HISTORY OF SHIPPING CONTAINER CONSTRUCTION
The first shipping containers were constructed in Japan, Europe, and later Korea, Hong Kong and Taiwan. Those countries accounted for about 90 percent of all shipping container production in the early days. When the world needed less expensive shipping containers, China delivered. Here is a timeline of China’s emergence into the shipping container manufacturing giant it is today:
- 1980: China entered into shipping container manufacturing in 1980 with the formation of China International Marine Corporation (CIMC) in Shenzhen, China.
- 1993: Thanks to China’s low cost of labor and its new standing as one the largest producer and recyclers of steel, China gained great momentum in 1993.
- 1995: Even Taiwan, Hong Kong, Japan, Korea and most of Europe were now producing their shipping containers in Mainland China.
- 2007: CIMC has been the largest manufacturer of ISO Containers in the world since 1996 and by 2007, China was producing 82 percent of the entire world supply of ISO shipping containers.
- 2021: Today, there are about 15 major manufacturers of Overseas Dry Cargo Containers, the most widely used shipping containers. China’s CIMC manufactures more than 50 percent of the 5 million-second Generation Overseas Dry Cargo shipping containers. CIMCO makes more than 7,800 20-foot Overseas Dry Cargo shipping containers every day. Maersk, Hapag-Lloyd, Evergreen, OOCL, Hyundai and other shipping container brands are manufactured in China.
SHIPPING CONTAINER CONSTRUCTION PROCESS
It may be surprising to know that shipping containers aren’t made solely machines, instead requiring a lot of manual labor from workers. Here is a look at the step-by-step manufacturing process of shipping containers.
How Shipping Containers Are Made? Worlds Amazing Modern Container Manufacturing 2021. YouTube, uploaded by MACHINERY PH on October 31, 2020, https://youtu.be/eOUB9DQFRXg
STEP 1: WALL PANELS
Shipping container construction begins with the wall panels. Large steel sheets are cut down into sheets, which are sand-blasted and primed to remove dust and other contaminants. They are then corrugated, which actually adds strength to walls and gives shipping containers their wave-like texture. The corrugated sheets are welded to the tubular frame.
STEP 2: FLOOR Framing ASSEMBLY
Floor frame assembly primarily consists of two longer I-beams that are perpendicular to each other. Smaller I-beams are then welded in between the longer I-beams to create a slab-like base. Once the welding is complete, the floor frame is sanded with a flap-disc angle grinder to remove any rough welding joints.
The flooring is marine-grade pressure treated with FDA-approved chemicals, including pesticides and anti-decomposing agents, to insure safety and longevity of the wood floors.
STEP 3: DOORS AND CORNER POSTS
Now that the sides of the container are made, the front and back of the container are constructed. Like the side walls, the doors are mainly made out of corrugated steel. Once the corrugated steel has been cut to size, it is encased in square steel tubing.
The doors are installed on the floor frame, followed by the wall panels. Then the corner posts, walls and door are welded in place and the roof panel is assembled and attached.
STEP 4: FINISHING THE BOX
The box is almost complete. Cranes are used to lift the door frames so they can be positioned on top of the floor frame and welded into place. The wall panels are lifted and welded next, and the roof panel is welded in place last.
STEP 5: Painting AND PAINTING
With the carcass of the shipping container now built, it needs to be primed and painted to provide protection from harsh environments. Priming (undercoating) is the first layer of paint to be sprayed on the container. This ensures that additional layers of paint stick better to the container and also provides an additional layer of protection for the container.
After the primer dries, the container is spray-painted several times. Multiple layers of paint ensure the container is protected against the harsh elements of sea travel, such as salt and water.
The flooring panels are varnished to prevent water and pest damage to the wood, and the floor is installed in the frame. Finally, the door is fitted with rubber seals and the bottom of the container is waterproofed.
STEP 6: FLOORING
Now, the wooden flooring needs to fit on top of the floor frame. Six plywood panels are used to floor the container. The pressure-treated panels are placed inside the container and screwed into the steel floor beams.
STEP 7: DECALS AND IDENTIFICATION
The shipping containers are now ready for company decals and logos. They also need labels with unique identification codes that can be used to identify the container from anywhere in the world. The identification code has 11 alphanumeric characters, each of which corresponds to a meaning.
The first three letters are used to identify the owner of the container. The fourth character is a Product Group Code, which can either be U, J or Z.
U = Shipping container
J = Any piece of equipment that can be attached to a shipping container, i.e. a power unit
Z = Trailer used to transport a shipping container
The fifth through 10th characters make up a serial number that is assigned by the container’s owner. This serial number is used by the specified container’s owner to identify the container. The final character is known as a Check Digit. It’s used to verify the previous 10 characters.
Once the container has been labelled, the door handles and locking mechanism are attached. A rubber seal is then wrapped around the doors to make sure they are water-tight.
STEP 8: WATERPROOFING AND TESTING
The final step in the shipping container manufacturing process is the spraying of the container’s underside with a waterproof sealant. If no defects or leaks are found, the container is now complete and can be transported to its intended location.
To learn more about shipping containers, their usage, and how to purchase one, contact the US. To watch a video of the shipping container manufacturing process, click here.
Sources
https://www.architectmagazine.com/technology/how-its-made-shipping-containers_c
http://containerhomeassociation.org/shipping-containers-industry.htm