Aisles are operating space
Aisles are not wasted space: they are where lift trucks turn, people move, loads are handled and replenishment occurs. An aisle that is too tight for the chosen equipment can reduce productivity and increase risk, even if it improves a floor-plan density calculation.
Equipment determines geometry
Required operating space depends on the truck or handling equipment, load dimensions, rack configuration and manoeuvre. Manufacturer data and competent layout design should be used for final decisions rather than a generic rule of thumb.
Separate movements where practical
Pedestrian paths, crossing points, dock approaches and vehicle routes deserve deliberate planning. Traffic controls are a safety matter as well as a capacity matter because congestion and crossing movements can constrain usable space.
Model scenarios, then validate
It can be useful to compare how different gross aisle allowances affect storage-zone capacity during early planning. That does not establish a safe aisle width. Final geometry must be verified against equipment requirements and applicable rules.
Practical questions
Should I use one utilization percentage for every warehouse?
No. Inventory profile, storage system, seasonality, staging demand, handling equipment and workflow can make the same percentage perform very differently in two facilities.
Can this guide be used to approve a rack or building change?
No. It is a planning resource. Structural, fire, building, accessibility and workplace-safety requirements must be established for the actual facility by the appropriate qualified parties and authorities.