How to Determine Cantilever Rack Capacity: A Complete Guide

Cantilever racking is a type of storage system that you can use to store lengthy or oddly shaped materials in your warehouse. The various materials that can be stored on cantilever racking include lumber, steel bars, tubing, and piping. The main difference between a cantilever system and traditional pallet racking is that there aren’t any vertical supports on the exterior of the racks.

Cantilever racks are made with uprights, brace sets, and arms. Selecting the right arms is crucial to ensure you’re able to meet your facility’s storage requirements. For example, straight arms are suitable for storing cartons and lumber. Inclined arms are required when you need to store cylindrical materials that might shift, such as tubes and piping.

The ideal rack capacity depends on the weight of your materials and the amount you need to store. Identifying the right rack capacity can help you increase efficiency and safety in your warehouse. In this guide, you’ll learn how to determine cantilever rack capacity.

Key Factors Affecting Cantilever Rack Capacity

From load distribution to column spacing, there are numerous factors that affect the capacity of a cantilever rack. Some manufacturers print load capacity information on rack components, which can help you make your calculations.

Load Distribution

You must evenly distribute loads on your cantilever racking system to avoid deflection and overload issues. If you use double-sided racks, make sure the loads are evenly distributed on both sides. When load distribution becomes uneven, your system’s capacity could drop by up to 50%.

Arm Capacity

Each type of cantilever arm can have a different capacity. For example, a standard 48 x 4 cantilever arm can support as much as 2,000 pounds. If the arm is made from roll-formed steel, its capacity could be lower than 2,000 pounds. Arms that are built with structural steel often have higher capacities.

Column Spacing

The columns in your cantilever system determine the rack’s strength. If the system has more columns, it will be stronger. Every column bears a portion of the load. If you intend to store lengthier items in your warehouse, proper column spacing is essential. When the columns are spaced far apart from one another, the capacity of your system will drop.

Rack Height

You must also consider the rack height when estimating the system’s load-bearing capacity. If your warehouse has a high ceiling, you can maximize your vertical space, which will help you increase storage efficiency.

The main drawback to using a taller cantilever rack system is that it will have a lower capacity per row or arm. Even though you’ll benefit from more storage space, it will be limited somewhat unless you choose to reinforce the system.

Flooring and Anchoring

Cantilever racks are designed to sit on a heavy base, which must be anchored to your facility’s floor. If your warehouse is already equipped with a concrete floor, you should be able to anchor this racking system to the surface without needing to make additional modifications.

Once you identify the material your floor is made with, consider the thickness of the concrete slab. Will the integrity of the concrete hold up after you anchor the rack system to the floor? Look for any signs of damage to the floor to determine if the material’s integrity has been negatively impacted.

Make sure the floor is level before you install the racking system. A level floor can increase the rack’s stability and weight capacity. If you don’t have a level floor, this is the one modification you need to make before you attempt to install the system.

How to Calculate Cantilever Arm Capacity

When calculating the cantilever arm capacity, make sure that the length of each arm is longer than the width of the product. If you have a load that can be placed 48 inches deep, the arms must be 48 inches or longer. If the arms are shorter than the product you intend to store, the capacity for the equipment will drop by a considerable amount. To determine your system’s rack capacity, use the following formula:

Weight capacity for every arm = Product weight per level / Number of arms

Each arm will support an equal portion of the load’s total weight. Once you identify the number of arms for each level, you’ll need to divide it into the total weight per level. This formula will give you the required arm capacity that your system must have.

Keep in mind that this formula is only effective if the products on the racks have been centered and evenly distributed. As mentioned before, uneven weight distribution can decrease each arm’s capacity by as much as 50%. This specific scenario leads to an issue called tip loading. You can avoid this problem by making sure that you don’t place too many products in one spot of the racking system.

How to Calculate Cantilever Upright Capacity

Once you’ve calculated the cantilever arm capacity, you must identify the upright capacity. You can determine this number by multiplying the arm capacity by the total number of arms for each upright. Make sure that you identify the height of your goods and storage area before you attempt to determine the upright’s capacity.

To calculate your storage area’s maximum height, consider the limitations that are in place. The maximum height can be limited by the forklift reach, ceiling height, local building codes, and sprinkler systems.

If your building is outfitted with ceiling-mounted ESFR sprinklers, local codes and regulations will limit the height of your products and racking system. You need to maintain a small amount of space between your sprinkler system and the storage racks. The maximum height for your cantilever rack uprights depends on how high your forklift will reach and your ceiling height.

When you decide to calculate the product height, you’ll first be tasked with identifying the number of levels in your rack system. Once you measure the height of your products, add at least four inches of space between the bottom of the cantilever arms and the top of your products. Maintaining this amount of space ensures that your products aren’t damaged while being lifted and moved by a forklift.

Consider the system’s arm height as well. Arms are typically around three to four inches. After you measure the arm and product heights, add at least four to six inches to the uppermost point of your storage.

Once you’ve obtained all this information, you can start calculating the capacity of your cantilever uprights. You can perform this calculation with the following formula:

(Number of arms x Total capacity per arm) / Number of uprights = Total capacity required for every upright

Make sure you calculate the capacity for each cantilever arm before you determine the weight limit for your uprights. Keep in mind that the load you place at the bottom of the system won’t adversely impact the upright’s rated capacity, which means that you should place the heaviest loads in your warehouse around the base of the rack.

It’s crucial that the upright’s capacity exceeds the load that’s placed on every level. Let’s say that you’re using a system with a dozen arms, each of which is rated at a 3,000-pound capacity. The system should have a total capacity of 36,000 pounds. When you use three uprights, you’ll need at least 12,000 pounds of capacity per upright.

Additional Considerations When Determining Capacity

When determining capacity, there are several additional factors you should consider.

Tip Loading: Avoid positioning heavier loads towards the end of the cantilever arms. If you don’t load your goods properly, you might experience tip loading, which can injure your personnel and damage the goods you’re storing.

Rack Configuration: You must also consider the configuration of your racking system, which can be either single-sided or double-sided. When using single-sided racking, you must maintain a similar weight across the entire length of the level. If you opt for double-sided racks, you need to maintain a similar weight of stored goods on each side of the system.

Manufacturer Specifications: When performing these calculations, you must consult the manufacturer guidelines to search for the load limits. While you won’t find this information on every component, any info you discover can help you make more accurate calculations.

How to Increase Cantilever Rack Capacity

There are several ways to increase the capacity of your cantilever rack. For example, you can adjust the arm spacing to ensure that no two arms are too far apart. You can also add cross-bracing to enhance the system’s stability and capacity.

Consider reducing the height of the system to increase capacity as well. Reconfiguring some of the rack components may be necessary to achieve greater load-bearing strength.

Conclusion

Determining the capacity of your cantilever racking is necessary if you want to avoid overloading the system and damaging the racks. You can calculate the cantilever rack capacity by identifying the capacity of the arms and determining how much weight the uprights can accommodate. To ensure the safe and efficient use of cantilever racking systems in your warehouse, make sure your employees understand the rack’s capacity and know how to evenly distribute the weight of goods during the loading process.