Recommended Clearances Between Pallet Racks and a Building's Structure

Posted by Sammy Bongiorno, ing. on September 1, 2018
Sammy Bongiorno, ing.
Find me on:

What you need to know about clearances in the warehouse.

Have you ever felt uneasy when someone gets a little too close to your personal space? In our day to day lives, there are no strict rules about what is too close for comfort. Some people go through life blissfully unaware that they make people uncomfortable by intruding on their space. Pallet racking clearance, however, has more specific rules and guidelines that dictate just how close they can get to any pallet rack component.

Pallet racks are structures designed to be self-sufficient and freestanding. Building components (i.e., walls, building columns, beams, etc.) are not typically designed to support additional loads from neighboring structures. Connecting pallet racks to building components allows forces to transfer between them, which could have unintended consequences. Unless a structural engineer specifically designed the structures to interact, it is not recommended to connect pallet racks to building components.

Pallet-connected to building
Figure 1. Example of a pallet rack connected to the building structure (not recommended)

Ensuring that pallet racks are not connected to a building component is not enough. To prevent contact between building components and pallet racks through vibrations (caused by operation, impact or a seismic event), pallet racks should have a minimum clearance from the building's structure. Current standards call for a minimum pallet racking clearance equal to:

  • 5% of the racking height with the building in the down-aisle direction
  • 2% of the racking height with the building in the cross-aisle direction

The hatched area in Figure 2 represents the required clearance between a rack and the building structure.

Figure 2. Plan view of building/racking structure separation

In the event of an impact or seismic activity, a pallet rack could damage a building component if it’s too close, compromising its load carrying capacity. Figure 3 shows an example of an upright that does not respect the recommended pallet racking clearance.

Multiplying the height of your pallet rack times 0.05 for down-aisle or 0.02 for cross-aisle directions will allow you to determine the necessary clearance for your pallet rack. For example, if your pallet rack is 240 inches tall (20 feet), the required clearance would be 12 inches (5% of 240) in the down-aisle direction and 4.8 inches (2% of 240) in the cross-aisle direction.

If you are certain that the topmost beam elevation will not be modified over time, the topmost beam height can be used instead of the rack's height to determine the required pallet racking clearance.


Upright in close proximity to building
Figure 3. Upright in close proximity to a building column


Minimum down aisle clearance
Figure 4. Minimum down-aisle and cross-aisle clearances

Other recommended clearances

Aside from pallet rack and building component clearances, there are other clearances to keep in mind in your warehouse. Storing pallets within the recommended clearances will reduce damage to pallet rack components and ensure safe and efficient operation.

Minimum clearances for proper handling and protection of pallet racks are recommended. Required general clearances for single deep/double deep pallet racks are listed in Table 1 below.

Table 1. Recommended clearances for single deep and double deep pallet racks

#

Clearance

Recommended space

1

Between two loads and between one load and the upright frame

At least 3 in.

2

Between the load and the overhead beam

At least 3 in. (and more for top levels safe handling)

3

Pallet overhang

Between 2 and 4 in. over the front and back beams

4

Between two loads in back-to-back cells

At least 4 in.

5

Service aisle

  • One-way traffic: At least the truck length including its load plus 6 in. on each side or according to the lift truck manufacturer’s recommendations.
  • Two-way traffic: According to the lift truck manufacturer’s recommendations

6

Main aisle

According to the lift truck manufacturer’s recommendations

7

Between load and an automatic sprinkler system

At least 18 in.

8

Walkways

  • At least 24 in. wide or more
  • At least 43 in. wide for direct access to an exit walkway
  • Free space of 80 in. above floor, unless a danger sign is posted

As shown in the table above, to avoid damage or unintended impacts with rack components, pallets should have a minimum clearance of 3 inches between two pallets or one pallet and the upright frame. Lift truck drivers should pay close attention and make sure there is adequate space on both sides of the pallet when placing them. Figure 5 shows a pallet stored directly against a column. Disregarding the recommended clearances can result in damage to pallet rack components.

Improver pallet storage
Figure 5. Improper pallet storage

Pallet racks are efficient structures for storing large quantities of merchandise, but standards must be followed to ensure they are used safely and remain free of damage. Following the recommended clearances from building components and other objects is an Important one.

Free Rack Safety Warehouse Poster - Order Now

Topics: Pallet Racks, Pallet Rack Safety, Rack Conformity, Rack Protection

Recent Articles

Making the Case for Pallet Rack Repair Kits

Today, we'd like to address a warehouse safety topic that concerns not only rack owners and operators, but maintenance... More

Essential KPIs to Measure the Performance of Your Warehouse

Being a warehouse manager is a balancing act, one that requires taking the right business decisions while facing whatever... More

Tricks of the Trade: 5 Tips on How to Inspect Racking Systems

We know it’s important to inspect racking systems to find damage. We know that the rack's load capacity should be... More