Although this might come as a surprise to some managers, space utilization in an effective warehouse peaks just under 30%. In other words, only 30% of the total warehouse space can be equipped with storage racks and shelves, while the remaining areas are divided between offices, restrooms, other functional niches, and, most importantly, aisles.
Depending on the type of racking systems employed in a warehouse, aisles can take up as much space as the racks themselves – sometimes even more. If too much room is assigned for aisles, the warehouse cannot reach its maximum storage density potential. If, on the other hand, aisles are too tight, this is likely to slow down operations considerably and even lead to more frequent workplace accidents.
As such, it is essential that aisles are just the right size for the proper functioning of a warehouse. But exactly how much space do you need between forklift racks? Below, you’ll find the information you need to make sure your storage space is designed optimally.
Aisle Size for Selective Pallet Racks
Selective pallet racks facilitate quick and easy access to each pallet in storage, but this comes at the cost of increased aisle space requirements. At most, two lanes of racks can be positioned back to back, with two aisles providing access on both sides.
Each aisle must measure 3m to 3.4m for reach trucks or 3.5m to 4.5m for counter-balanced forklifts.
Aisle Size and Configuration for Double-Deep Racking
Racks can be designed to accommodate anything from double-deep to six-deep pallets, which offers significantly more storage density per system. For example, when using double-deep racks, selectivity is reduced to 50% of pallets, but up to four lanes of racks can be positioned back to back, with two aisles for access on both sides.
This can drastically reduce the number of aisles per warehouse, while each aisle should measure between 3m and 3.4m.
Aisle Types for Drive-In vs Drive-Through Racking
Drive-in/drive-through racking can go as far as 10 to 12 pallets deep, which makes it one of the most dense storage systems currently in use. The average aisle size for this type of racking ranges from 3m to 3.4m, for reach trucks, or 3.5m to 4.5m, for counter-balanced forklifts.
Drive-through racking requires additional aisles, however, because access must be permitted both at the front and at the back of each lane. The advantage of the latter is, of course, increased selectivity.
Narrow Aisle Racking
Narrow aisle racks are very similar to selective pallet racks in that they commonly provide 100% selectivity for deposited pallets. However, the former are designed to be accessed with special vehicles such as turret trucks or articulated trucks, which considerably reduces the required aisle size.
Only two lanes of racks can be positioned back to back, with two aisles providing access on both sides, but aisles needn’t measure more than 1.8m to 2.2m each.
Optimal Aisle Space for Mobile Racking
With mobile racking, individual (selective) racks are placed on floor reels so that they can be moved automatically with the activation of a button. As such, large number of lanes can be pushed together in blocks, with room for only one aisle per block. When needed, entire lanes are moved in such a way as to open up the aisle at the correct location.
An aisle in mobile racking must be wide enough to accommodate a forklift vehicle, which usually requires no more than 3m to 3.4m to be operated safely by an employee.
Aisle Size for Automated Storage and Retrieval Systems
Automated storage and retrieval systems are some of the most modern, as well as space-, cost-, and time-effective racks on the market. An ASRS warehouse can tremendously boost storage density and the speed of operations, while at the same time reducing labor costs.
Because vehicles employed in ASRS are not used by human beings, they need very little room to operate safely. Aisles in such racking systems range from 1.8m to 2m, which is even less than with narrow aisle racking.
In addition to the specifications above, you should always take into account that each warehouse rack manufacturer may use a slightly different system design, while different types of forklifts also come with unique requirements. It is therefore essential that you discuss the question of how wide your warehouse aisles should be with your provider in order to get a more exact estimation.