If you ever work in a warehouse, definitely you have been familiar with U-flow or through-flow layout. These two layouts may sound different, but they are designed based on one assumption: The traditional arrangement of racks (where racks must be parallel with each other, and if possible, the cross aisle should cut the aisles between racks at right angle) is the most effective.

Figure 1: The traditional layout (Source: Kevin Gue’s blog)
By common sense, some people might think that this grid-like pattern can reduce the accidents, increase the throughput and minimise the contingency. Many academics challenge this assumption, inter alia, Kevin R. Gue, Russell D. Meller, Ömer Öztürkoğlu, etc.

In 2008, Professor Kevin Gue and Dr. Russell Meller published Aisle Configurations for Unit-Load Warehouses on IIE Transactions where they proposed alternative warehouse layouts that are more effective than traditional layouts by reducing the travel distances and travel time. Two these layouts are briefly discussed in the Whole Life Asset Management study guide. They are named Flying-V layout (or Fan-shape layout in the study guide) and Fishbone layout (or Herringbone-shape layout in the study guide).
Figure 2: a) Flying-V warehouse optimized for single-command operations; (b) Fishbone warehouse optimized for single-command operations (Source: Kevin Gue’s blog)
These two layouts were created on the assumption that there is only one pickup and deposit point (P&D) at the centre bottom of the warehouse. Based on calculations and computer simulation, the two authors concluded that in these layouts, the travel distance could be reduced by 20% compared with an equivalent traditional warehouse. You may watch the demonstration in the video below:

Gue and Meller’s paper gained attentions from logistics and warehouse professionals in the US. A company named Generac Power Systems applied the Fishbone layout to their warehouse facility in 2007. The initial results seemed positive as senior managers and workers liked the new layout. However, there were also concerns about safety within the Fishbone warehouse.

The two layouts also have other limitations:

• Gue and Meller created these layouts on the assumption that there is only one pickup and deposit point. In reality, many warehouses have multiple points of access and deposit. Flying-V or Fishbone may be inapplicable in these warehouses. But an adjusted Fishbone design may allow multiple goods-in docks and single dispatch area.

Figure 3: A floor plan for distributor’s warehouse in Florida, USA (Source: Kevin Gue’s blog)

• These layouts are designed for unit-load operations where items are packed into large units, usually pallet-base. Vehicles and equipment are required to handle discrete loads, not to pick small items within a load.

To compensate the above limitations, many research papers try to discover the optimal layout for multiple operations (both for unit load and order picking), or try to find the best layout for order picking.

Until now, the best warehouse layout for every situation has not been found. The selection of the warehouse layout depends on several factors such as the available space, number of docks and access points, the available equipment and vehicles, etc. We hope that from this simple blog post, you can find the most suitable solution for your warehouse facility.