I recently wrote two blog posts on fitting pallet racking layouts within building columns of different sizes (see my post on 40’ columns spans and my post on 50’ column spans). Different layouts result in different aisle widths, which can be a matter of preference. You can tighten the aisles to fit in more racks, but you’ll end up with slower loading and unloading. Leave too much space however, and you pay a penalty on storage capacity.
Want to see an example of this dynamic at the extreme? Check out this video of a warehouse racking layout using 9’ aisles. Loading or unloading just one pallet is a pretty hard job for these standup forklift operators!
Reach truck vendors suggest 9’-6” aisle widths, which is sufficient, but I prefer 10’ as a minimum. That gives enough space for operating, particularly in lower height, slower paced buildings. For double-deep racks, I add a bit more space since the truck is longer due to the double reach mechanism. In a faster-paced or greater height buildings, wider aisles (11’ or more) are generally preferred.