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Forklift Aisle Requirements – A Guide for Best Warehouse Layouts

Written by editor on October 8, 2011 – 12:07 pm - (85333 views)

Here are the forklift aisle requirements guide for the various types of forklifts. Be sure to note that “clear aisles” means the dimension between products (pallets) stored in the aisle.  This is generally 6 inches narrower than where the rack is placed in what is call “rack to rack” or “steel to steel” aisle dimensions.  The rack is placed a further 6 inches back if the pallets are overhanging the pallet racking 3 inches each side.

Forklift Aisle Requirements Guide

NOTE:  This is information is offered as a rough guide only.  When designing a warehouse or pallet rack layout, check with the lift truck manufacturer for the engineered right angle stacking aisle requirement to avoid expensive errors.

Wide Aisles – Counterbalanced Forklifts

Wide Aisles are used for counterbalanced lift trucks.  The rule of thumb when sizing a lift truck such as a sitdown 4-wheel or 3-wheel fork truck is:

Head Length of the Lift Truck + Length of Load + 12" for Maneuverability + 6" Pallet overhang

Head length: This means the distance from the back of the forklift to the front of the load backrest.

Load length: This is the length of the pallet down the stringer (the long 2″x4″ that runs the length of the pallet) plus any product overhang.

Forklift Aisle Requirements for a Stand up forklift

Stand-Up Forklift

Remember, pallets sit on a beam and overhang the beam by 3″ (usually if a 48″ long pallet).

4-Wheel Counterbalanced Forklift Aisles

Generally, 4-wheel counterbalanced trucks have forklift aisles sized for 12 to 14 feet.

3-Wheel Counterbalanced Forklift Aisles

Many warehouse managers use 11 to 12 foot aisles for a 2-wheel counterbalanced lift truck.

Stand-up Counterbalanced Forklifts

For this kind of forklift, 10.5 to 11.5 feet work

Narrow Aisles

Narrow Aisles refer to Reach trucks and Deep Reach trucks.  Generally, when we say “narrow aisles” we are describing a 9-foot aisle.  However, with Reach trucks, it is important to size the aisle both for storage and productivity.

If you measure an aisle at Home Depot, you will find that it is 8.5 feet.  This is narrower than most warehouse managers would set their aisles, however, storage is the primary goal at Home Depot. They are not designing for in-out pallet, pallet moves and productivity.  What would work best for your operation may be quite different. It is highly recommend that you consult with a warehouse design expert to ensure your dimensions are optimal for your forklift equipment, warehouse style, and operational usage.

Reach Truck 

crown reach forklift

Crown Reach Truck

Many warehouse managers use a 9.5′ aisle with an extra 6 inches for pallet overhang, setting the pallet racks 10 feet apart.  Be sure to use the correct method for placing and retrieving pallets, however.  The length of a Reach Truck with a 48 inch pallet is approximately 104 inches.  Driven like a counterbalanced forklift, 104 inches won’t work in a 108 inch aisle (especially since the clear aisle would be 6 inches less).  But if the lift truck is driven like a Reach Truck (as it is designed to be driven), a 9-foot aisle will work fine.

So how do you drive a Reach Truck?

To properly take advantage of a narrow aisle Reach Truck, approach the racking holding the inside baseleg (outrigger)  off the front of the pallet rack’s column by 8 inches.  Line the load wheel up just to the side of the of the upright column and turn your steering wheel 90 degrees.  This will cause the Reach Truck to pivot into place.  The pallet will be partially inserted into the pallet rack bay.  Now extend your pantograph (scissor reaching mechanism) and deposit the pallet.

Reach Truck Aisle

For a Reach Truck aisle, use 9 to 9.5 foot aisles and add 6 inches for pallet overhang (3 inches each side). (For more on this, see Reach Trucks Explained)

Deep Reach Truck

Use a full 12 inches to 18 inches more when sizing a Deep Reach Aisle.  The lift truck is longer because of the longer scissor and it has a heavier capacity design. Therefore, a Deep Reach Aisle is 10 to 11 feet wide

Very Narrow Aisles

Very Narrow Aisles are defined as an aisle narrower than a narrow aisle of 9 feet.  Turret trucks use 30% to 40% less aisle than a narrow aisle Reach Truck. Note however that the cost of this lift truck can be double.

Also, Very Narrow Aisles are usually guided.  Beware of operating VNA lift trucks in an unguided aisle.  Expect lower productivity, product and rack damage, as well as poor visibility. This is due to the steep angle from the floor to the top beam in the aisles.

Turret Truck / Swing Reach

A very narrow aisle turret truck uses an aisle of 10 inches to 18 inches wider than the width of the lift truck (assuming a 48 inch length x 40 inch width) load.

Clear aisles can be as narrow as 66 inches (5.5 feet).

Rack to Rack dimensions require 72 inch aisles (due to 3 inch pallet overhang).

Order Picker / Order Selector / Stock Picker 

Yale High Level Stock Picker OS030EC

Yale Order Selector

A free wheeling cherry picker / orderpicker requires 18″ clearance per side when traveling down an unguided aisle.

A guided orderpicker can operate with 6 inches clearance on either side of the lift truck.

This picker is generally the width of a pallet (which is 40 inches), therefore:

  • Unguided Cherry Picker clear aisle is 76 inches
  • A Guided Cherry Picker clear aisle is 52 inches
  • When used in a Turret Truck Aisle, the order picker will use the same aisle dimension of 72 inches, but requires the picker to have a wider platform width.

Note: always contact your lift truck manufactured prior to anchoring your pallet rack.  Aisle requirements change with new models and operating requirements.  Also, pallet rack installation should be left up to the pros.

Consult your licensed local pallet rack installation company to be sure you are installing your racking to the local building code requirements.

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