Guide to Stacking Shipping Containers Safely

stacking shipping containersStacking shipping containers is a process that requires precision and accuracy. Heavy equipment operators and warehouse workers need to be aware of the guidelines for stacking shipping containers in order to ensure safety and efficiency.

Although OSHA has established clear guidelines for shipping container safety, many companies aren’t sure of the proper way to stack containers. (FLC), a recognized leader in online forklift certification training since 2002, offers 100% OSHA-approved forklift safety courses, which let you teach your workers how to correctly stack shipping containers

The Basics of Stacking Shipping Containers on Land

Once containers have been offloaded from a ship, a worker must determine how many containers can be stacked atop each other, the maximum shipping container stacking height, and the proper container stacking methods.

Correct stacking techniques revolve around two key factors, which are stack height and stack stability. Here are the basics:

Container Stack Height Regulations

On land, there are no height restrictions on stacking shipping containers, although reasonable caution should always be exercised. Your company’s safety supervisor should establish on-site stacking procedures, which will vary depending upon whether the containers will be stacked in warehouses, on open land or The maximum safe shipping container stacking height should take into account the type of lift equipment that’s used and where the containers will be stacked.

Container Stack Stability

Stacking containers for an open sea voyage is more difficult than stacking them on stable Whether they’re stacked on board a ship or on land, the heights of the stacks present different safety hazards. For example, the containers’ bulk and weight create an even higher level of risk when bouncing around on the deck of a cargo vessel.

Regardless of the storage location, workers should always check with safety personnel or their supervisors before stacking shipping containers.

Best Practices for Stacking Cargo Containers on Land or Ship

Here are some recommended procedures for safely stacking shipping containers on land:

1. Inspect the Containers

Shipping containers should always be inspected for visible signs of cracks or dents before stacking. Check the sides, sub-flooring and corners posts for signs of damage or wear. Repair or replace any units that show signs of structural damage. Containers should also be checked inside and out for the presence of rust. Immediately repair or replace any units that show signs of structural damage.

2. Use Corner Posts When Stacking

For maximum stability, containers should be stacked corner post to corner post. A container’s four corner posts should align directly with the corner posts of the containers immediately above and below. When stacking containers of different sizes, such as stacking one 40-ft. container and two 20-ft. containers, the larger 40-ft. container should be placed on top, since placing the two smaller containers on top will increase the risk of the stack collapsing.

3. Use Lashing Rods to Prevent Sliding

Whether they’re on a truck or ship, containers should be secured with lashing rods to keep them from sliding while in transit. Adding twist-locks to the containers will increase stability, and will also reduce the chances of an accident.

4. Ensure Only Properly Trained and Certified Forklift Operators Stack Containers

Because there’s a certain degree of risk involved, handling a forklift requires skills acquired through training and experience. Forklifts are bulky and slow-moving pieces of equipment, but even at low speeds, an impact can cause serious damage to people, products, and equipment, including tip-over accidents that can result in fatalities

Techniques for stacking shipping containers on the deck of a ship are different from those used for stacking them on land. Here are tips for stacking cargo containers on a ship:

1. Choose Appropriate On-Board Stowage

The two types of storage on a container ship are “fore and aft” and “athwartships.” Fore and aft stowage onboard the ship is lengthwise, while athwartships refers to horizontal stowage at right angles to the ship’s center. The correct type of stowage depends on the size of the ship and weather. Fore and aft storage offers better protection against high winds, crashing waves, and rough seas.

2. Use Corner Posts to Stack Containers

When stacking like-sized containers on top of each other, align them corner post to corner post, since the posts and flooring are designed to bear the weight of both the container itself and those above it. By doing this, all four corner posts of the larger top container rest on corner posts of the containers immediately beneath them.

3. Secure the Containers

Traveling on the sea is much rougher than traveling across land, which makes it even more important that your stack of shipping containers is secured against slipping and sliding. Lashing rods and twist-locks are used to secure the container stacks to the vessel’s deck, which also helps prevent slippage.

4. Choose the Right Lift Equipment

Forklifts are frequently used to stack containers on ships, although their use depends on the type of forklift and the height of the stack. Container forklifts are designed to handle both 20-ft. and 40-ft. containers. Some types of forklifts may not be able to handle the job, in which case cranes might be needed. The capabilities of a particular type of forklift should be confirmed before it’s used to stack containers.

Do You Need to Use a Forklift to Stack Containers?

container stacking

Learning how to stack shipping containers all comes down to the equipment you’ll use for the job. A forklift is a great option to securely stack containers. Whereas a truck that sets containers down cannot be used to stack them, a forklift can be used to pick up containers and stack them one on top of another. 

Before using a forklift to stack containers, it is important to do the following:

  • Verify the forks can extend the length of the container and ensure the container safely remains in place when it is carried upward or downward.
  • Ensure that the forks will not poke through the floor of the container.
  • Confirm that the forklift can handle the container’s weight.

Prior to using a forklift to stack containers, it is important to plan ahead for the project. A forklift inspection can be performed to ensure the lift is functioning properly and the operator knows exactly what to do. If any issues are found during the inspection, they should be addressed before a lift is used to move the containers.

In the event that a forklift cannot handle stacking shipping containers, a crane may provide a viable alternative. Generally, a crane and material handling company can offer assistance to ensure you can properly stack your containers.

Are There OSHA Requirements for Stacking Containers for Shipping?

OSHA provides guidance in terms of how to stack shipping containers safely. It does, however, indicate that containers must be stacked in a way that they won’t slide or collapse. OSHA also states that containers must be stable and secure and won’t create a workplace hazard.

If containers are not stacked properly, there is a risk that they could fall onto a worker or equipment. Moreover, there is a chance that containers could collapse, which could endanger workers and cause financial losses.

When it comes to storing containers for shipping, be cautious about shipping container stacking regulations. Otherwise, a business that ignores safety puts its staff and operations in danger.

Business owners are responsible for teaching workers how to safely stack containers for shipping. Without appropriate training, workers can inadvertently stack too many containers on top of one another. This can lead to workplace accidents, injuries, and fatalities. It can also result in OSHA violations.  

By enrolling your workers in forklift certification training, you can provide your employees with valuable insights into shipping container safety best practices. The training teaches workers how to properly lift containers and stack them. It explains why workers need to account for the weight of containers and other factors. As a result, the training empowers your forklift operators to work cautiously. Best of all, it can help your forklift operators become productive and efficient, to the point where they have no trouble safely and securely stacking containers at warehouses and other worksites.

Do Your Employees Need Forklift Certification to Stack Containers?

Anyone using a forklift when stacking shipping containers will be required to get certified first. In fact, OSHA requires all lift operators to be trained thoroughly before they can legally use a lift. During training, operators learn how to move containers and other objects as safely as possible. Anyone who plans to stack containers using a lift must be trained first. Training helps to minimize the risk of an accident while prioritizing shipping container safety. Training also helps your organization comply with OSHA regulations and avoid expensive penalties and fines.

Why is it Important to Learn the Proper Techniques for Stacking Shipping Containers?

Shipping and cargo containers make it possible for products to be transported throughout the world in a safe and cost-effective manner. They’re easy to lift, unload, and store and can be used to hold virtually any type of product that needs to be shipped. Regardless of what is included in your containers, the key to workplace safety and preventing employee injuries is proper stacking. If your business needs to stack cargo containers, it’s important that you and your workers understand how it’s done the right way. 

Although OSHA has established clear guidelines for shipping container safety, many companies aren’t sure of how to stack shipping containers properly. (FLC), a recognized leader in online forklift certification training since 2002, offers 100% OSHA-approved forklift safety courses, which let you teach your workers how to correctly stack shipping containers.

What to Expect from FLC’s Forklift Safety Training

Here’s some of what your workers need to know about stacking shipping containers that they’ll learn through our training:

  • How to safely stack shipping containers
  • Shipping container stacking height limitations
  • The maximum number of shipping containers in a stack
  • Inspecting shipping containers before stacking
  • Best container stacking methods
  • And much more

To create a safer and OSHA-compliant workplace for your employees, enroll them in one of our forklift training programs today.

Frequently Asked Questions About Stacking Shipping Containers

If you’re still unsure of how to stack shipping containers in the safest and most efficient way possible, allow us to address your questions. We’ve assemble some of the most frequently asked questions on the subject below:

How Much Weight Can You Stack on a Shipping Container?

The amount of weight that can be stacked on a shipping container varies based on the amount of weight in each container, the number of containers stacked, and other factors.

A typical shipping container can hold many tons of cargo. On average, a 20-ft. container may weigh up to 5,000 lbs. and carry loads up to 60,000 lbs. Comparatively, a 40-ft. container may weigh up to 10,000 lbs. and carry loads up to 120,000 lbs.

Shipping containers have a maximum stack load that must be followed. The maximum stack load is listed on a container’s CSC plate or documentation provided with the container. By following these limits, you can prioritize shipping container safety in every setting.

Can You Stack Open-Top Shipping Containers?

Shipping container stacking regulations state that pen-top shipping containers must be closed during transport. These containers may be opened and loaded from the top and can be used to transport heavy loads. But, the top must be covered with a soft or hard roof for safe transport.

Can You Stack Containers Perpendicular?

Most containers are designed to be stacked horizontally or vertically. And, containers should always be stacked in the way they were designed. Furthermore, containers should not be stacked in a crisscross pattern.

Are Containers Bulletproof?

Shipping containers offer immense strength and durability. But, they are not necessarily bulletproof. Containers are not necessarily flameproof, either.

Do You Need to Use Container Stacking Pins?

Container stacking pins help you stack containers on top of another. Each pin includes a plate with a locking pin at either end. This locking pin slots into holes cut out of corner casts. As such, the locking pin can be engaged or disengaged, depending on whether you need to lock or unlock two containers.

Locking containers together can minimize the risk that they’ll move during transport. So, it typically pays to invest in container stacking pins.

How High Can Shipping Containers be Stacked?

According to shipping container stacking regulations, containers may be stacked up to nine high, depending on the maximum stack load of the lowest container. It is usually better to err on the side of caution, particularly when it comes to stacking containers that contain heavy loads. Thus, if you are unsure if a container can support multiple containers stacked on top of it, you may want to avoid stacking too many containers at once.

What is the Best Container Stacking Method?

The best method for stacking cargo containers depends on whether containers are being transported on land or by ship. Regardless of how containers are being transported, OSHA guidelines must be followed.

Prioritize Shipping Container Safety

The safest methods of stacking shipping containers all boil down to education and training.  When a forklift operator has been properly trained, they are much more likely to prioritize safety on the job. FLC offers comprehensive forklift training to guide operators through industry best practices while also teaching them how to minimize the odds of workplace injuries. If you’re hoping to comply with OSHA guidelines and avoid expensive fines and penalties, you’ll want to certify your employees via FLC. 

No matter how you use forklifts in your organization, FLC covers all the important elements of forklift safety practices on the job. Our easy to understand format ensures that even the most novice of forklift operators can learn effectively. Please contact us online or call us today at (888) 278-8896 to enroll your workers in one of our forklift training programs. That way, you can ensure that your workers can become OSHA-approved forklift operators right away.

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