Pallet Racking - Other Common Types

Other Common Types

Many types of pallet storage racks are available with different designs to fulfill specific functions or create specific advantages. When deciding on the type of pallet rack to use, several basic considerations have to be taken into account:

• Desired storage density
• Floor space and building height
• Placement of building doors and columns
• Inventory accessibility
• Inventory rotation
• Item/load size and weight
• Optimal storage design
• Cost of materials and installation

Some of the most common types of pallet rack systems used include:

1. Drive-in and drive-through (sometimes spelled Drive-thru) are storage rack configurations that allow the forklift to drive directly into the lane of stacked rows (called a bay). The difference between a drive-in and a drive-thru pallet rack system is simply whether the bays have an entry at only one end, or at both ends. Drive-in rack systems use a common entry and exit, while drive-thru systems have entry points at either end of the bay. Because a drive-in racking system has only one entrance, it uses what is called a LIFO (last in, first out) storage method. With only one entrance, the last pallet put into a row is necessarily the first one to be taken out. A drive-thru storage system, with two different entry points, can also use a FIFO (first in, first out) storage method. With a FIFO system, pallets are loaded in one end and are pushed back to the other end, where they are then at the front of the row on the opposite side. The first pallet put into such a row is the first one taken out at the other end. This system is advantageous for material with an expiration date or wherever shelf life is a major concern.
2. Push-back pallet rack systems are designed around the principle of organizing space by depth rather than width. This depth arrangement greatly reduces aisle space and increases storage density. In this configuration, each bay can be up to six pallets deep; each pallet stored on wheeled carts that fit onto rails. The rails are slightly angled toward the load/unload side of the rack in order to take advantage of gravity, saving enormous amounts of energy for moving heavy pallets. When a forklift sets the pallet onto the cart, it drives forward and causes the pallet to bump the next pallet, causing the entire row of pallets to roll backwards. When removing a pallet from the front position the remaining pallets immediately stage themselves forward so that the next available pallet can be accessed. Push back rack is a LIFO (last in, first out) storage system.
3. Pallet flow systems are high density pallet storage systems that utilize depth to increase capacity. This system uses a slightly inclined rail with rollers that allow pallets to move easily along the sloped plane. These systems are also called gravity flow or dynamic flow systems. The pallet flow system often has complex motion and braking systems to control the speed of the moving pallet. Pallet flow racking systems are either a FIFO (first in, first out) or a LIFO (last in, first out) storage system. If the system is loaded from the back and unloaded from the front, its FIFO; if the system is loaded and unloaded from the front its a LIFO system.
4. Compact mobilized pallet racks also known as motorized mobile pallet racks or mobile industrial rack system, are designed to maximize the use of warehouse storage space. Mobilized compact pallet racks can reduce your pallet storage area in half, or double the capacity of your pallet rack storage in the same floorspace area. Mobilized pallet racks save space by converting static access aisles into productive storage space. The mobilized compact rack storage system mounts rows of pallet racks onto heavy-duty rolling carriages and places them on floor tracks. Rows of pallet racks (up to 96’ long) move sideways along the floor tracks creating a movable floating access aisle. Typical warehouse storage facilities may have dozens of static access aisles but only one or two forklifts capable of accessing stored materials. Mobilizing pallet racks reduce the number of access aisles to match the velocity requirements of your storage area. Rows of pallet racks are moved by pushing a button or by remote control, which opens access aisles when and where they are needed.

Mobilized pallet racks have helped many organizations reduce or eliminate new building construction costs, auxiliary warehouses, building expansions, and decrease ongoing operational costs (lighting, energy, insurance) by maximizing the use of their storage floor space.

Some disadvantages of high density pallet storage systems are; less access to all stock at any given moment (although if the stored product is all the same, it should not matter), and the expense of such systems. Selective pallet rack systems are considerably less expensive per pallet position than their higher density counterparts. In most medium to large facilities, however, high density pallet rack systems are essential, since they provide the efficiency of time and high cost facility space is better optimized.