5 Frequently Asked Questions About Shipping Containers

container yard


Often the most outstanding inventions in modern history do not share the same attention it deserves. This short post shares some of our respect for the humble shipping container and its impact on the global economy. As Author Marc Levinson aptly titled his book;

How the shipping container made the world smaller and the economy larger”

How the era of containerization took the economy by storm is no small feat. The cost of producing a container made from steel, rivets, and wood made it massively scalable, the uniformity of its size made it transferrable and transportable, the enclosed nature of the box protects the cargo inside.

We may think that it is common sense to create a box for cargos to be put into and transported, but it is not until the 1970s, approaching its 50-year anniversary of creation, that the idea became universally adopted.

Just imagine the amount of coordination and the amount of economical effort each country has to go through to make this “box” adopted globally.

Here are some of the frequently asked questions about the humble shipping container that one may ask. Hopefully, people will come to appreciate such an astonishing yet unassuming invention.

How does shipping liners track their containers?

We got curious about how shipping liners track millions of containers in circulation around the world. Especially when in this day in age containers there are so many types and purposes of containers that it would seem to be a daunting task just to pinpoint where their container is located.

Containers are labeled with an ISO Standard Container Numbers  

First of all, containers are built with a container number that is unique to that container. It comes with an owner code to identify it’s owner, a category code, serial number and also a check digit.

Naturally, not all containers are owned by shipping liners as there are shippers that have regular shipments big enough to justify owning their own containers as a cost-benefit. Some are also owned by specialized container leasing companies.

The ISO standard container number is not mandatory, but shippers generally follow the ISO standard container numbers too, because there are many parties involved in the transportation cycle and tracking a different type of number may prove to be a problem, especially in this era of computerization.

Container yards keeps stock of the inventory

For the majority of the shipping containers in circulation around the world, shipping liners must have a presence in the country it ships to. Primarily to process documentation and collect revenue for the company.

Shipping Container Yard

However, it can be a costly undertaking if the shipping liners rent or buy a yard just to keep its shipping container for the next customer to use.  So, shipping liners tend to not own long term assets in it’s servicing countries and prefer to outsource aspects of its business to local businesses.

Primarily container yards, a designated location for shipping liners to store and repair their containers. Shipping liners tend to outsource it to local container yards.

This helps the liners reduce its fixed cost and only pay the depot or yard when used.

The container depot or yard operators are responsible to provide a report to the shipping liners of the containers in the yard. This is largely digitized, employing OCR, or EDI systems to sync with liner’s in-house systems.

Terminal Operators are also responsible to track liner’s containers in and out of the port, a service the shipping liners acquire at some cost too.

What are shipping containers made of?

How are Shipping Containers made

The sides of the container

The containers manufactured are generally ubiquitous in size and materials made. Unless it is made for special purposes like refrigeration, or liquid storage. The sides of the containers are made from corrugated steel.

The science behind corrugation is that it helps with improving structural integrity and also helps to withstand external forces by increasing the surface area on each side. You can see that in corrugated boxes too and they retain its general structure even when stacked on top of each other.

The inside of the container

The floor of the container consists of plywood. There are several reasons why plywood is chosen over steel.

  • Low heat conductivity
    Wood does not conduct heat, it absorbs heat rather than reflects heat, that stops the container from turning to a natural oven in high heat weather conditions. This is useful when transporting cargos that are heat sensitive like foodstuffs and combustible goods.
  • A high degree of pliability
    Wood is highly pliable as it is fibrous. If a heavy cargo is placed on steel that is not corrugated, it may bend to shape from the force of the cargo itself.

The corners of the container

Container corners are made from steel structures that reinforce the box and give it structural integrity. The door panels, container floor, and container sides are all made from reinforced steel and also insulated with rubber stops to make sure the container is watertight.

Other materials used

Of course, there are other materials used for the construction of an ISO grade container, some use bamboo to construct the floorboard, aluminum instead of steel or fibrous polymer as a base material as well.

All in all, the material used for container construction may differ but the overall shape and structure remain the same.

How long does shipping containers last?

Generally speaking, there is no expiration date on a container that stops liners from using them, so long as the container is regularly inspected, serviced and deemed as “seaworthy” by the convention of safe containers (CSC).

Conventionally, every container is ISO Certified Container is manufactured with a CSC Plate. The CSC plate functions as a birth certificate of the container that has details of the manufactured date, the maximum tare weight allowed, maximum stack weight, and most importantly, the date of the last inspection.

Regulation dictates that the container has to be inspected after 5 years of its manufactured date and every interval of 30 months after the 5 years.

What is container “seaworthiness”

Crucially, much of the claims of container damages and cargo damages arise from each party’s interpretation of container “seaworthiness”

We have tried to examine whether there is a concrete definition of “seaworthiness”, much like the outdated Hague/Visby rule that most shipping liners apply in their Bills of Lading.

Containers with its details printed on the door panels

The Hague and Hague Visby rule suggests that:-

“The carrier shall be bound before and at the beginning of the voyage to exercise due diligence to

(a) make the ship seaworthy;
(b) properly man, equip and supply the ship;
(c) make the holds, refrigerating and cool chambers, and all other parts of the ship in which goods are carried, fit and safe for their reception, carriage and preservation.

Shipping Liners can exercise its due diligence to make the container equipment seaworthy by regularly servicing its container.

But it is a responsibility shared by both ship owners and shippers too. To avoid any unforeseen damages for both parties, even the shipper should be responsible in checking the CSC plate for it’s servicing history to ensure that the liner is diligent and the container is “Seaworthy”.

Where are shipping containers made?

Shipping Containers, since the 1970s has revolutionized the logistics industry, improving intermodal transport and increasing transport speed and efficiency. The boon of this creation has, in certain sense, accelerated global growth in the 20th century.

A shipping container is manufactured with cheap labor, competitive raw material cost, and in a location that is geographically cost-efficient.

China comes to mind, in the early 2000s, China ticks all the boxes. Qingdao China International Marine Containers (CIMC), located in Shenzhen, Guangdong, produces 56% of the world’s dry marine containers.

In addition, the world’s top 10 port is full of ports from China, making the logistical cost of staging the container to it’s intended customers lower. China also dominates the world crude steel production consistently over 50%. Logically container manufacturers will produce its containers closest to the source.

How secure is a shipping container?

Transporting goods through the relentless waves and sun may be a cause of concern for importers and exporters. They are concerned whether the precious cargo can withstand extreme weather temperatures or not, also the impact the cargo withstands from shocks and knocks from transferring the containers.

As robust as a shipping container is, how well does it protect its valued cargo from within?

Are shipping containers airtight?

The short answer is no, shipping containers are not airtight, although the containers are insulated on all sides with rubber seals and adhesive. Some containers come with specially designed holes to promote air circulation to suit certain cargos, cargos such as animals.

Are shipping containers watertight?

Container manufacturers test their containers rigorously and the key feature manufacturers test is its ability to withstand corrosion and water seepage.

A container that is regularly inspected to the satisfaction of the CSC standards will have to be watertight.


We equivocate the invention of shipping containers to the invention of toilet flushes. It is not glamorous, but it gets the job done. We also definitely can state the case that both inventions even save lives.

Until a better solution is created for transportation, shipping containers are here to stay for a foreseeable future.






Hello! I'm Kelvin, I work as a custom broker and I'm thrilled with having the experience to share my industry knowledge with you. I hope that you enjoy reading them as much as I do posting them.

3 thoughts on “5 Frequently Asked Questions About Shipping Containers

  1. It’s good to know that a regularly inspected shipping container must be watertight. My brother-in-law wants to start an international business but he is afraid that his products will get ruined by moisture while being shipped. I’ll tell him to not worry about it as long as he uses a regularly inspected container that passes all the tests.

  2. Thank you for sharing that shipping containers are excellent because they have low heat conductivity. My friend was thinking of renting and then eventually owning a container. I will share with him about shopping container.

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