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.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 uprightIt 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.
