Storage Density and Aisle Usage
Drive – in pallet racking is designed to achieve high – density storage. It has deep – lane storage, where forklifts drive directly into lanes to store and retrieve pallets. This reduces the need for multiple aisles between pallet rows. For example, in a drive – in system, a single aisle can serve multiple storage lanes, allowing for a large number of pallets to be stored in a relatively small footprint. The storage density can be several times higher than that of traditional selective pallet racking.
In terms of aisle usage, the forklift spends more time inside the storage lanes and less time in traditional wide aisles. This is because the forklift enters the lane to access pallets, and the aisle is mainly used for accessing the entrance of the storage lanes.
Selective pallet racking provides easy access to each individual pallet. It has aisles between every row of racks, which allows forklifts to quickly access and retrieve any pallet at any time. However, this means that a significant portion of the warehouse space is occupied by aisles. For example, in a typical selective pallet racking layout, aisles might take up 30 – 50% of the total floor space, depending on the width of the aisles and the layout of the racks.
The forklift mainly operates in the aisles between the racks and can access pallets from the front of the racks without having to drive into a deep – lane structure.
Push – back pallet racking also offers relatively high – density storage. It uses a system of nested carts or rails that allow pallets to be pushed back into the rack. Each lane can store multiple pallets, similar to drive – in racking, but with a different access mechanism. In push – back racking, pallets are stored on a first – in, first – out (FIFO) or last – in, first – out (LIFO) basis depending on the design.
Aisle space in push – back racking is more optimized than in selective pallet racking but not as extreme as in drive – in racking. The forklift accesses the pallets from the front of the rack and uses the mechanism to push the pallets back or retrieve them.
Accessibility and Retrieval Method
✅Drive – in Pallet Racking:
As mentioned earlier, it operates on a LIFO basis. When retrieving pallets, the forklift has to remove the pallets from the back of the lane first. This can be a disadvantage if specific pallets need to be accessed quickly. For example, if a warehouse needs to retrieve a particular product that was stored earlier in the lane, it may have to move several other pallets out of the way first.
The access to pallets is limited to the entrance of the storage lane. Once a forklift is inside the lane, it can only access the pallets in that lane.
Selective pallet racking offers the highest level of pallet selectivity. Forklifts can access any pallet directly from the front of the rack at any time. This makes it ideal for operations where quick access to individual pallets is crucial, such as in order – picking operations for e – commerce warehouses or distribution centers that handle a wide variety of products.
The retrieval method is very flexible, and pallets can be accessed in any order, depending on the requirements of the warehouse operations.
✅Push – back Pallet Racking:
Push – back racking can be designed to operate on either a FIFO or LIFO basis. If it’s a FIFO system, the first pallet placed in the lane is the first one to be retrieved. This is beneficial for products with expiration dates or those that require a first – in, first – out inventory management. In a LIFO system, the last pallet placed is the first to be retrieved, similar to drive – in racking.
The access to pallets is from the front of the rack, and the forklift uses the push – back mechanism to store and retrieve pallets. This provides more flexibility than drive – in racking in terms of accessing specific pallets.
Forklift Operation and Skill Requirement
✅Drive – in Pallet Racking:
Forklift operators need to have a high level of skill to drive into the narrow storage lanes without damaging the rack structure or the pallets. The forklift has to precisely align with the lane entrance and maneuver carefully inside the lane. The risk of collisions is higher compared to other types of pallet racking, especially when the forklift is entering or exiting the lane.
The forklift operation is more complex as it involves driving into a confined space and dealing with the LIFO retrieval method. Operators need to be aware of the order in which pallets are stored and retrieved to avoid mistakes.
The operation of forklifts in selective pallet racking is relatively straightforward. The wide aisles between the racks provide more room for the forklift to maneuver. The main skill required is accurate positioning of the forkliift to place and retrieve pallets from the front of the racks. The risk of collisions with the rack structure is lower compared to drive – in racking.
Forklift operators can focus more on quickly accessing the desired pallets without having to deal with the complexity of deep – lane storage.
✅Push – back Pallet Racking:
Forklift operation in push – back racking requires an understanding of the push – back mechanism. The operator needs to know how to properly push the pallets back into the rack and retrieve them using the system’s design. The skill level required is intermediate between that of selective pallet racking and drive – in pallet racking.
The risk of collisions is relatively lower than in drive – in racking as the forklift mainly operates from the front of the rack, but still requires attention to the push – back mechanism and the position of pallets.