Minimum Distance Between Pallet Racking Systems & Building Structures

Posted by Sammy Bongiorno, Eng. on April 12, 2022
( Last updated on 18 July, 2022 )
Sammy Bongiorno, Eng.
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Are you looking for warehouse racking safety guidelines? Here's what you need to know about clearances in the warehouse.

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 the minimum distance between racking and the building's structure to comply with safety rules like OSHA regulations.

Connecting Racking Systems to Building Components

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, which is why storage rack clearance is so important. 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.

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

Pallet Racking Spacing Requirements with Building

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 activities in the warehouse, impact, or a seismic event), a specific storage rack clearance from the building's structure should be respected. Unless you have previously determined by seismic analysis the amplitude of movement of the racks, current standards require a minimum warehouse 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 warehouse rack and the building structure.

Plan view of building/racking structure separation

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 distance between pallet racking.

The minimum distance between racking

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 your storage rack clearance. 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 distance between pallet racking.

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

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

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Other recommended clearances

Aside from storage rack clearance and the distance with the building components, 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 storage rack 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 storage rack clearance can result in damage to the pallet rack components.

Improper pallet storage
Figure 5. Improper pallet storage

Storage rack clearance: warehouse safety guidelines to remember

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 minimum distance between racking and respecting clearance from building components is an important one.

Inspecting your racking systems on a regular basis is the best way to stay on top of OSHA safety standards.

Rack inspection management tools like the Damotech Platform can help you view and track your rack inspections, for a more efficient way to ensure warehouse safety. The user-friendly dashboard provides visual representations of your warehouse layouts and allows you to track inspections in real-time - from virtually anywhere! If you're interested in learning how you could improve the way you manage your rack inspections, watch the 6-minute demo.

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Topics: Pallet Racks, Rack Conformity, Rack Protection