Shipping containers, otherwise known as intermodal or cargo containers, are huge storage boxes used for transporting goods from one place to another.
They are made to withstand atmospheric corrosion caused by environmental elements such as rain and saltwater while protecting the contents.
These containers come in standard sizes across countries to allow for ease of transportation. They are typically 8ft wide and 8.5ft high and are available in lengths of 20ft and 40ft. There are also containers that are 9.5ft high and are known as High-Cube (HC) containers.
Types of Shipping Containers
There are 6 types of shipping containers that are used for shipping goods, typically via land or sea freight. The type of container used depends on the nature of the items being transported.
1. Dry storage containers
Suitable for: Dry goods and materials
Dry storage containers are the most common type of container used in the shipping industry. They are used for transporting goods that do not require a certain temperature range for storage.
2. Flat rack containers
Suitable for: Heavy machinery, automobiles, pipes
Flat rack containers only come with the bottom and 2 sides (usually the shorter sides). This means that odd-shaped and oversized cargo which cannot fit into dry storage containers can still be transported as they can be loaded from the top or sides. The cargo is then covered by tarpaulin to prevent any damage.
There are mainly 2 types of flat rack containers – collapsible and non-collapsible. Collapsible flat rack containers allow both ends to be folded or detached onto the base of the container. This helps to save space when it is not in use.
On the other hand, non-collapsible ones have fixed sides that cannot be folded down. While they are not as space-saving as their collapsible counterparts, they are structurally more rigid.
3. Open side containers
Suitable for: Heavy machinery, automobiles, pipes, LCL shipments
Similar to dry storage containers, open side containers have the usual lockable double door on the rear end. However, this type of container has 2 additional bi-fold doors on one of the longer side walls. This is useful when cargoes are too big to be loaded through the rear.
Space can also be utilized more effectively with the additional doors and goods are more easily accessible.
4. Open top containers
Suitable for: Tall and heavy articles such as cranes and heavy machinery that require forklifts
Open top containers have roofs that can be easily detached. They are used when cargos are too tall to fit into the standard dry storage containers. Without the roof, goods can be loaded through the top using forklifts.
There are 2 types of open top containers – hardtop and soft top. Hardtop containers have a detachable steel roof while soft top containers have a tarpaulin roof that can be secured to the containers.
5. Refrigerated containers
Suitable for: Perishables, pharmaceutical goods such as vaccines
Refrigerated containers, also known as reefers, are specialized containers that are able to regulate the internal temperature to ensure that goods are transported at the ideal temperature.
Besides being able to maintain a temperature range of -30°C to 30°C, reefers are also able to control the humidity level of the container and remove excess water.
6. Tank containers
Suitable for: Liquids, gasses, powders (hazardous and non-hazardous)
Tank containers or tanktainers are cylindrical in shape and used for transporting liquids, gasses and powders.
There are various types of tank containers for carrying different types of goods. They can be classified into food-grade tanks, reefers, gas tanks and lined tanks. Lined tanks are used to transport highly hazardous contents and have extra security frameworks.
When looking at shipping containers, there are 3 weights to take note of – tare weight, payload and gross weight. These weights are usually found on the outside of the container doors.
- Tare (unladen) weight: Weight of the container itself, without any cargo.
- Payload (net weight): Maximum weight of the cargo that a container is able to hold.
- Gross weight: Total weight of the container and the maximum load (payload) it can hold.
The weight of shipping containers differs depending on their type. For instance, a HC container would weigh more than a standard one as more metal is used for its construction. Reefers would also be heavier due to the integrated refrigerator units.
In general, the tare weight of a typical 20ft and 40ft dry container are about 2,300kg and 8,330kg respectively.
Shipping containers are graded according to their structural standards and extent of physical wear and tear. These grades provide an indication of the condition of the containers.
While there is no international grading standard, containers that are used for international transportation are required to have a valid safety approval plate, or CSC plate. This ensures that they are able to meet safety standards.
Shipping containers that no longer meet the CSC standards are sometimes repurposed as storage containers or even converted into office spaces, hotels and residential units.
Types of Container Packing
There are 2 types of container packing used by freight forwarding companies – full container load (FCL) and less-than-container load (LCL).
Full Container Load (FCL)
FCL shipments are those that occupy the whole container. This is typically used when merchandisers are shipping a large amount of goods and are able to fill up the entire space.
Less-than-container Load (LCL)
LCL is when a shipment shares a container space with cargo from other shippers. It is also known as consolidated freight and is normally used for low-volume shipments.