What Is Cantilever Racking? Here Are The Basics
Cantilever racking is a free storage system that is designed to store long or unconventionally shaped materials such as piping, steel bars, tubing, and lumber. Cantilever racking is different from other types of storage systems like pallet rack or wide span storage rack due to the absence of vertical supports on the outside of the system.
Cantilever rack consists of three main components: uprights, arms, and brace sets.
Uprights consist of a vertical column and a horizontal base that is bolted to the column. A minimum of two uprights is needed to form a single starter bay. Uprights can either be single-sided or double-sided.
Arms are the heart of the rack system. The proper selection of arms is critical to meeting your storage requirements. For example, straight arms can be used to store stable loads such as lumber, steel sheets, cartons, and skins. If you plan on storing cylindrical items that could roll during storage, such as piping or tubes, inclined arms should be used instead of straight arms or you can add a lip to the end of the straight arms.
As noted in the diagram above, brace sets are bolted between each pair of uprights in a single cantilever rack bay to add lateral stability to the system. If you plan on using taller uprights (heights of 15’ or greater) then cross bracing is recommended to increase the stability of the system.
Determining The Needs of Your Cantilever Racking
Already determined the needs of your cantilever racking system and need a guide to install it? Click here to jump straight to the installation section.
How many cantilever rack arms do I need and how should they be spaced?
To protect your products from deflection, characterized by “sagging” product between the arms, it’s important to use the right number of arms in each of your cantilever rack bays. A lack of support from not using enough arms in your system also puts unnecessary pressure on the arms which could also lead to premature damage of your cantilever rack.
A simple test can be performed to determine the number of arms you need in your cantilever rack system.
- Place two wooden blocks 2 feet apart on the floor to represent the cantilever arms.
- Load your product on top of these wooden blocks and look for any deflection, or flex in your product
- If you don’t notice any deflection, then a standard two-arm system would fit your needs
- If you do notice deflection, continue to add additional wooden blocks (cantilever arms) at 2-foot increments until deflection is not present
Brace sets generally come in 1 foot wide increments which is why you want to initially test for deflection with wooden blocks set at this length apart. Never space the arms farther apart than ½ the length of the material you are storing. For example, if you’re storing products that are 8’ long, the arms should not be longer than 4’ apart from each other.
It is natural for products to overhang the outside of the arms by some amount. That’s what a cantilever rack system is used for. However, it is recommended that the overhang should not exceed ½ half the distance from upright centerline to upright centerline. For example, if you determine that your cantilever rack system will utilize two arms that are 2 feet apart, then the product overhang should not exceed 1 foot on each side.
How do I keep my products from rolling off my cantilever rack?
As mentioned above, cantilever rack arms are typically available as straight or inclined. Straight arms can be used to store stable products such as lumber, steel sheets, cartons, and skids. Inclined arms can be used to store cylindrical items such as piping and tubing, which have a tendency to roll forward.
Cantilever racking arms can be accessorized by adding a lip to the arms to help prevent materials from rolling off the front of the arm.
How long should my cantilever rack arms be and how do I calculate their capacity?
Determining cantilever arm rack length
The length of your cantilever arm racks should be a little longer than the product width. For example, a load 48” deep will require arms that are at least 48” long. If this is not observed, the rated capacity of the arm will be severely diminished. Refer to the diagram below to see the right (and wrong) way to store products on your cantilever rack.
Determining cantilever arm rack capacity
To ensure that your cantilever rack arms have enough capacity to store your products, a simple formula can be used:
Weight capacity for each arm = Total product weight per level / Required number of arms
Each arm supports an equal amount of the load’s weight. By determining the number of arms per level and dividing it into the weight per level, the required arm capacity can be determined.
It is important to note that arm capacities calculated by the formula above assume that products are evenly distributed and centered. If you store products on the end of your cantilever rack (shown below), the capacity of the arm can be reduced by up to 50%. This type of loading is called tip loading, which is an incorrect method of storing your products on a cantilever rack system.
How tall should my cantilever rack uprights be and how do I calculate their capacity?
The height of your cantilever rack uprights will be dictated by two main factors: the maximum height of your storage area and the height of your products.
Calculating the maximum height of your storage area
The maximum height of your storage area can be limited by several factors, such as the actual ceiling height, forklift reach, sprinkler systems, and local building codes. In short, the maximum height of your cantilever rack uprights equals the lesser of:
- Ceiling height less 48” of space between the bottom of the ceiling and top of your product; or
- The maximum height your forklift will reach minus 4”. This is to ensure that you have enough clearance to safely lift your products up and off the cantilever arms.
Calculating the product height
To factor in the product height into the selection of your cantilever uprights, start by determining the height of the product itself and the number of levels you need in your cantilever rack system. It is important to add a minimum of 4” between the top of your product and the bottom of each cantilever arm to account for the safe removal of your product from the system by a forklift.
Arm height also needs to be considered when selecting your cantilever rack uprights. Depending on the capacity requirements your cantilever arms may vary between an average of 3” to 4”.
Once the product height and arm heights are determined, you should then add another 4” to 6” to the highest point of your product storage. Refer to the diagram below for an example of how to visualize the height of your cantilever rack uprights.
Calculating the cantilever upright capacity
Another simple formula can be used to calculate the capacity of your uprights:
(Number of arms x Capacity per arm) / Number of uprights = Capacity required per upright
It is important to note that the capacity of your cantilever arms needs to be determined before calculating the capacity of your uprights. Refer to the section in this article about calculating cantilever rack capacity if you haven’t done so already.
The formula is derived from multiplying the number of arms per side on the load of each arm. The load placed on the base does not diminish the rated capacity of the upright, therefore, the heaviest loads should be placed on the base of the cantilever rack system.
To illustrate the capacity equation, if your system uses 12 arms and each arm has a capacity of 2,500 lbs, the total capacity equals 30,000 lbs. If your system is using 3 uprights, then a minimum required capacity of 10,000 lbs per upright is needed.
(12 arms x 2,500 lb. capacity per arm) / 3 uprights = 10,000 lb capacity needed per upright
What type of cantilever rack bracing and width should I be using?
Brace sets are bolted between the pairs of your cantilever racking uprights to provide additional stability to the system. The width of a brace is measured from the centerline of an upright to the centerline of the next upright. Braces are typically sold as a set.
If your cantilever rack system is more than 15’ tall, a second brace set that consists of X-bracing is typically required.
The width of your brace set should closely match the total width calculated in the section of this article: How many cantilever rack arms do I need and how should they be spaced? For example, if your cantilever rack is 10’ long, you would need two 60” wide brace sets. If your cantilever rack was 10’ long and 20’ high, then you would need two 60” X-brace sets.
Installing Your Cantilever Racking
Things To Know Before Starting
Cantilever rack should only be installed by qualified, trained personnel who are experienced in storage rack assembly
Always adhere to the concrete anchor manufacturer’s installation instructions for slab drilling, hole cleaning, and anchor installation If your cantilever rack comes with instructions, review all the diagrams in their entirety before beginning
Inspect all of your cantilever rack arms, uprights, braces, and anything else that comes with your systems for damage immediately. Do not proceed with the installation if any of the items appear damaged. Reference the packing list for the inventory of materials. Do not proceed with the installation if there are any missing items. Check your items for part numbers to double-check that all of the materials are there. If the part numbers do not match or if you notice missing parts, do not proceed with the installation.
How To Install Your Cantilever Racking
Tools You Will Need:
- Electric Impact Wrench
- Straight Line Laser or Chalk Line
- Black Permanent Marker
- Tape Measure
- Socket Wrenches
- Impact Sockets
Step 1: Lay out the rack footprint
Lay out the rack footprint on the floor. Snap a down-aisle chalk line defining the main aisle, and snap cross-aisle chalk lines defining the edge of each cantilever baseline.
Step 2: Lay out the starter bay on the floor
Lay out the starter bay on the floor, consisting of two columns, the required bases, and the required arms. Refer to your manufacturer’s diagrams for the hardware requirements and torque specifications.
Step 3: Connect the cantilever rack base to the column
Connect the cantilever rack base to the column using the hardware supplied with your cantilever rack system. Ensure that the bolts are torqued to spec.
Step 4: Anchor your cantilever rack to the floor
Install the wedge anchors into the cement floor with the hardware provided. Use shims are required per your cantilever rack manufacturer’s specifications. It is recommended that you stagger the anchors in your base for maximum stability
Step 5: Connect the arms
There are typically 4 bolts required per arm. Use the supplied hardware to connect the arms to your upright, determined by the calculations and requirements in the previous section of this article.
Step 6: Connect arm accessories to the arm
If you are using pipe stops or arm lips, attach them to the front of the arm using the hardware provided by the manufacturer.
Step 7: Construct the second column
Following steps 3 through 6, erect the second column of your cantilever rack system by securing the base to the column, installing the arms and any additional arm accessories.
Step 8: Install the bracing
Once both columns and the arms are built, connect the bracing to the back of your cantilever rack system using the hardware provided by the manufacturer. Structural connectors need to be tightened to the snug-tight condition, which can be attained by a few impacts from an impact wrench or the full effort of a worker with an ordinary spud wrench that brings the connected plies into firm contact.
Step 9: Build additional adder bays as needed
Using the instructions outlined in steps 1 through 8, continue to erect and build adder bays to supplement your starter bays until the ideal rack system and footprint are achieved.
Cantilever Racking Systems & Installation Services in Michigan
If you have not yet purchased a cantilever racking system, American Storage & Logistics has a wide variety of new and used cantilever racking systems, arms, uprights, and braces - in stock and ready for same-day pickup at our warehouse in Grand Rapids or next day delivery to the Lansing, Battle Creek, Grand Rapids, and Kalamazoo areas. Shop our website to view our online store that contains a full catalog of cantilever rack inventory.
If you do not feel comfortable with installing cantilever racking on your own, or need help with calculating the requirements of a proper cantilever racking system, click here to learn more about our warehouse installation and design services. Alternatively, you could give us a call at 616-246-8700.