Basic Warehouse Layouts and Their Impact on Despatch Operations

The layouts of modern warehouses can vary widely. However, the layouts of most warehouses are versions or combinations of just three major layouts. These are described here.

(i) The “linear” or “through-flow” layout is the simplest of the main three warehouse layouts and, arguably, the most efficient. This layout features three zones, which correspond to the operations performed in each. In zone one, goods are received; in zone two, received goods are stored and later picked; in zone three, goods picked are dispatched. Each operation has its own distinct zone that is linearly sequenced along a straight line, with receipt being the first, dispatch last, and storage/picking the bridging operation/zone. Three zones make up this layout and the three are connected in the simplest order possible, i.e. 1, 2, 3. Normally, paths/flows do not intersect, so materials should not, at least in theory, cross pathways and the flow is always from first to final stage in linear fashion. This layout is highly manageable, logical, intuitive for operatives, and of the three requires least in the way of sophisticated planning and configuration of the surrounding area. One major disadvantage of this layout is the difficulty posed by moving MHE from the receipting zone to the despatch zone, because the path would require operatives to move through the storage/picking zone, which in busy times reduces efficiency. The layout also requires vehicles to load and unload at opposite ends of the facility. During busy times, vehicle movement outside the facility may become bottlenecked, especially if the roads leading to the structure are not purpose built to service the facility’s loading/unloading zones.

(ii) The second main warehouse layout is the “inverted ‘T’”. In this configuration, the receipting and despatch zones are next to each other, with the storage/picking zone above or below despatch (rather than before, which is the case in the through-flow layout). In this layout, sharing of MHE and operatives between the first and final zones is straightforward and convenient in distance, visibility, and time terms. Because vehicular movement between loading and unloading bays is minimal (compared to the through-flow layout), because the facility may have a more economical footprint due to its box-like layout, and because this layout is likely to require simpler access roads, warehouses with this layout maybe cheaper to build and operate. Naturally, there are disadvantages too: far from creating convenience, adjacent loading and unloading points can, in times of peak activity, become a congestion point. Paths of goods will cross inside the facility, meaning operators must work with caution to avoid collisions. Crossflows can slow/impede the internal movement of goods, and the sharing of MHE and operatives between the first and third zones can create efficiency reductions because resource sharing becomes itself a task requiring time, coordination, and management. Barriers, floor markings, wall signage, and other forms of alert may have to be used to prevent collisions, misuse of staging points, and loading/unloading errors (especially if very short-term or zero storage time is an objective, i.e. crossdocking operations are being performed).

(iii) The “U-flow” or “cross-flow” layout is the last of the three major warehouse layouts, and the most complex. As in the inverted T layout, the receipt and despatch zones are side-by-side. The storage/picking zone can be above or below the other two stages, but the path of flow is an arching (U-shaped) arrow that cuts through a three-section storage/picking zone. The three sections demarcate areas dedicated to the storage of fast-, medium-, and slow-moving goods, with the slowest-moving goods located furthest away from the adjacent receipting and despatch zones. This layout simplifies stock management so could, at least in theory, make more rational use of the warehouse’s shelf space. However, separation of goods into such sections may mean that shelf space is not used economically. For example, there may be a period in which slow-moving goods arrive in very high volume, resulting in that section of the warehouse’s storage zone being full-to-capacity while the other two sections are relatively unused but must still be travelled through by pickers and putters-away. This is the main and unique disadvantage of the U-flow layout. Its main advantage is the proximity of the fast-moving goods section of the storage/picking zone to both the receipting and despatch zones. This should minimize pick and put-away times for most goods. Its other disadvantages and advantages are the same as those of the inverted T – see (ii).