The Warehouse Rack Layout Aisle Width Decision

The Warehouse Aisle Width Conundrum      

As warehouse consultants, we are fortunate to visit and improve hundreds of distribution operations. The majority, but not all, of the operations require forklifts of some sort. Upon starting my career, one of the things I expected to see in the operations was more standardization of forklift types and, by extension, aisle width. However, that is not the case. Operations of similar applications and volumes can often have different forklifts and aisle widths. Here, I’ll explore some reasons why this may be:

Facility – Oftentimes, the facility may be the constraint. When creating pallet rack layouts, column lines cannot be in the aisles and are best buried in the flue spaces. As such, sometimes the column grid guides the aisle width decision. Also, the facility could have limited height, encouraging bulk floor storage where possible, which limits the truck types used.

Warehouse Management System (WMS) – Some types of racking, such as double deep, drive-in or pushback, require additional functionality to the WMS. Without the functionality, many types of rack cannot be used optimally, which affects the truck type and aisle spacing.

Item Profile – If an item is heavy or bulky, it may require a certain type of truck (for example, a counterbalance instead of a reach) or an extra-long aisle for maneuverability. The reverse is true if an item is too small and only fits in shelving.

Inventory Profile – If the inventory profile contains many pallets of few SKUs as opposed to many SKUs of few pallets, it affects the optimal racking method, thus affecting aisle width and truck decision.

Order Profile – If items are picked in full pallets as opposed to each or case quantities, the best picking method will then drive the truck and rack selection.

Though two operations may appear similar, there are many factors that go into selecting the right aisle width and forklift type. It is not a one size fits all solution nor an easy decision - it requires analysis of several variables.