Container stacking is the best way to achieve efficient space utilization. At the same time, stacking storage containers requires attention and knowledge of practices to prevent shifting, maintain structural stability, and ensure the process is carried out safely.
In this guide, we will look at various factors that should be taken into account when it comes to stacking shipping containers so that everything goes well and your modular construction is 100% safe and functional.
The Purpose of Container Stacking
So why is container stacking among the most popular options for using storage containers? The answer is simple: this approach allows you to use space in the best possible way. This is especially valuable if you are dealing with locations where the land is at a premium, so you need to find a solution to achieve maximum functionality of the space within the existing conditions.
Stackable shipping containers can offer greater flexibility for a variety of projects, whether it be modular buildings or on-site storage.
The most common use cases for shipping container stacks include:
Port Storage and Logistics
Stacking shipping containers is an ideal option in the case of ports and logistics, as these fields usually involve high volumes of cargo requiring storage in a limited space, so the issue of utilizing this space is crucial for companies. With stacked shipping containers, it becomes possible to reduce clutter and improve the organization of different types of cargo. For example, you can group cargo by directions, types, dates, etc., thereby making loading and unloading faster, increasing the efficiency of processes.
Modular buildings
Another area where stacking storage containers can be extremely useful is construction. From temporary offices and commercial spaces to residential buildings, modular construction has become popular in the last decade. Due to structural stability, durability, and customization, containers provide high reliability and withstand even the harshest weather conditions, making the storage container stack an attractive option and an effective solution.
Space-saving Solutions
Since containers are great when it comes to storage, the stack shipping containers solution allows you to use space most functionally, making this approach one of the best space-saving options, especially if you are dealing with densely populated areas or land with a small footprint. So, when looking for temporary or permanent storage or additional workspace, it makes sense to consider shipping containers.
Shipping Container Stacking Regulations
When stacking containers, careful consideration should be given to the process, as containers are not lightweight pieces of kit, so it is critical to eliminate the risk of collapse. The primary factors that require attention include weight distribution, environmental conditions, and height limitations.
In addition, it is essential to familiarize yourself with local and international safety regulations in advance to avoid possible legal complications, as well as to minimize the risk of tipping, ensuring that containers are safely stacked.
Maximum Height
Height is a critical aspect when stacking shipping containers because placing layers on top of each other raises the center of gravity. This factor should be especially taken into account in areas with harsh environmental conditions, such as strong winds.
In addition, some regions may have their own legal limits and guidance regarding the height of stack shipping containers, so it is worth familiarizing yourself with the regulations in advance.
Most often, it is allowed to stack up to five or six levels high. This is a standard limit in the shipping and storage industries.
Also, if we are talking about residential or commercial buildings made of containers, the maximum height is typically three levels, since building codes, modifications, occupancy requirements, etc., should also be considered in these cases.
Maximum Weight
Another crucial aspect is weight. Since storage containers weigh quite a lot, it's a good idea to check the safe load limits of the bottom containers before filling or stacking them, and to make sure the weight is distributed evenly throughout the stack.
Overloading can lead to structural failure, so it is essential to ensure the stability of the structure during shipping container stacking.
Weather and Environmental Factors
Some factors, such as weather and environment, are beyond our control, so special attention should be paid to how safely the containers are stacked and whether they can withstand environmental impacts and temperature variations during the container stacking process.
It is best to use weather-resistant coatings or designs. Also, you can fasten and anchor your containers; this may include anything from additional strapping and bolting to embedding into foundations.
Inspecting Containers
Regular inspection is the best way to ensure safety and compliance with shipping container stacking regulations, allowing timely detection of damage or wear and tear, as well as non-compliance with the guidelines. Since containers may be transported overseas and exposed to harsh sea winds and saltwater, it is always worthwhile to carefully assess the container in various aspects, including the integrity of locking mechanisms, corner posts, areas of structural stress, rust, corrosion, etc. Therefore, conduct a thorough inspection of your shipping containers before you start stacking.
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Shipping Container Stacking
It is recommended that a systematic approach to shipping container stacking be used, which includes a range of aspects from site and equipment preparation to alignment and stacking techniques.
Stacking Equipment
The main equipment includes forklifts and cranes:
Forklifts
The proper forklift for stacking shipping containers should include:
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Forklift pockets (69" from the inside of one pocket to the inside of the other pocket)
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If the forklift cannot spread that far, use fork extensions that are at least 8' long
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Forklifts should be strong enough to support 20' (weight 5,000 pounds) and 40’ (weight 10,000 pounds) containers
Before starting the process, inspect the forklift to ensure everything goes safely and smoothly.
Cranes
Sometimes, a forklift may not be enough, then it makes sense to hire a crane. It is best to find the closest crane and material handling company to the site, as they can also help you get the right equipment for your project. Cranes are the main option if your project involves higher stacks that a forklift can’t reach.
Site Preparation
The next step is to prepare the site to ensure a safe and efficient stacking process.
Stacking on Land
A stable and level foundation is a must if you are going to stack containers on land. First, lay a gravel base, construct a concrete pad, or undertake ground grading. This provides a stable shipping container foundation, facilitating the process.
Stacking on Ship
Stacking containers can also be done on a ship. This process is a bit less manual. The first thing to do is make sure the deck is prepared to handle the weight and distribution of the containers, so check the area's structural integrity and fix areas of damage or weakness in advance.
Aligning Shipping Container
When the stacking area is ready, the next step is the alignment of containers to ensure their stability. It is essential to eliminate even small misalignments or uneven weight distribution to avoid the risk of tipping or collapse.
Use alignment tools or machinery to achieve safe and precise positioning.
Shipping Containers Stacking Method
There are several ways of stacking, the main and most popular methods include vertical and offset stacking.
Vertical Stacking
Vertical stacking is one of the best methods and is perfect for uniform container sizes. Stack containers length to length and width to width. This ensures the most efficient use of space. At the same time, vertical stacking requires alignment and secure fastening to prevent any shifting or toppling.
Offset Stacking
An alternative method that is often found in modular construction is offset stacking. This approach means that containers are stacked in a way that appeals aesthetically or has a functional necessity, for example, a container stacked on top of another in an ‘L’ shape.
It should be noted that this method requires additional planning and engineering, as well as reinforcement to ensure stability.
Shipping Containers Security
The last step is securing. Choosing the best way to secure your shipping container is especially important if containers are going to be in transit. Use appropriate locking mechanisms to prevent shifting or separation.
Lashing Rods
Lashing rods are designed to hold the bottom layers of the stacked containers to the vessel. This helps ensure stability when travelling through areas with harsh weather conditions. Also, the additional use of twist locks is recommended in case of high stacks.
Twist Locks
Twist locks allow each container to be secured together and provide additional stability by fastening into each of the four corner posts and securing the container either to the ground or another container.
FAQ
How Do Shipping Containers Lock Together?
Containers can be secured with lashing rods and twist locks, ensuring structural stability.
How High Can You Stack Shipping Containers?
Depending on where you plan to place the stack. For example, on ships you can stack shipping containers up to 7-9 layers, in ports usually up to 5-6 layers, and in warehouses most often up to 4 layers.
How to Stack Shipping Containers Without a Crane?
You can use forklifts with container spreaders or special container trucks with hydraulic lifts if you are dealing with low stacks.
How Many Shipping Containers Can You Stack?
Standard 20 and 40 ft containers can be stacked up to 9 layers high when fully loaded, and up to 12 layers high when empty, depending on their structural strength.
What are the Rules for Stacking Shipping Containers?
Key aspects include mandatory use of twist locks, checking dimensional compatibility, compliance with maximum load, surface levelling, consideration of wind loads, and port safety requirements.
