A surprising amount of warehouse managers don’t consider the aisles between their shelves as much as they should.

We all know the importance of well-placed warehouse shelves, but what a lot of people don’t realize is that the space between them can be just as important.

More than just ‘the space the workers walk down,’ warehouse aisles can help dictate the flow of work, what kind of equipment can be used, and more. While every warehouse has different needs for space and flow, warehouse aisleways typically come in three styles: wide aisles (WA), narrow aisles (NA), and very narrow aisles (VNA).

Wondering which one would work best in your warehouse, or just curious as to what the differences are? Here’s a guide to the differences and advantages of each:

Wide Aisles:

Wide aisles, also referred to as ‘conventional aisles,’ are the most commonly seen style of aisle way in warehouses. These aisles serve as paths between pallet racks or wire shelving that allow workers to travel between shelves (or even between points in the warehouse) to place items. Generally, wide aisles are 12 feet wide or wider, offering ample space for products and workers to travel through. These shelves work best in settings where multiple workers or forklifts need to travel down each aisle, and are a good solution for high traffic areas or warehouses where space for shelves isn’t at a premium.

Narrow Aisles:

Narrow aisles tend to cap out between 8 and 10 feet wide in most settings. The reduced space from narrow aisles brings with it some advantages and disadvantages, but works well in smaller warehouses where space is at a premium. While the smaller space between shelves means less room for workers or forklifts, it does allow for more shelves to be stored in the warehouse itself (and kept together more closely), increasing the potential amount of inventory that can be stored overall. Narrow aisles do require additional safety measures and care when using equipment like forklifts, and special safety measures (such as gates, barricades, or safety railings) are going to be a must when travelling the aisles.

Very Narrow Aisles:

A relatively new development in warehouse layouts, very narrow aisles (as you can tell from the name) are the smallest of them all. Measuring in at 6 feet or less, these aisles reduce space between shelves dramatically, to the point where only specially-designed (and smaller) forklifts can fit between them, often equipped with special guidance systems to help them navigate these cramped quarters. However, there are a lot of advantages to this sort of aisle way, namely the amount of inventory you can store. The reduction in space between the shelves means you can store much more product and keep more types of shelves in your warehouse than with other methods – you just have to be careful about how you use it.

Each type of aisle will work better for some warehouses than others, and finding the best one for your warehouse will help your productivity and inventory levels more than you might expect.