Pallet racking is a widespread system for handling the storage of items on pallets. The pallets are stored in rows and on multiple vertical levels. Warehouse storage on pallet racks efficiently uses otherwise wasted vertical space and improves overall organization in a warehouse. To decide what is best for your needs, read through our pallet rack buyer’s guide.
Selective pallet racks are the most common type of pallet storage. A selective rack uses uprights and a pair of cross beams to create a “shelf” for storing a pallet.
You’ll determine the number of levels or shelves per bay based on the height of your pallet and your warehouse ceiling height.
Double-deep racks store one pallet load behind another in a structure that’s twice as deep as a selective rack. Double deep racks double storage, but they limit access and flexibility. For example, to access the rear pallet load, the front pallet position must be empty.
Double handling is necessary unless pallets are stored on a last-in/first-out basis. In most cases, two pallets with the same product are stored in a slot of a double-deep rack. This also limits flexibility and requires a deep-reach lift truck to access loads in the rear position.
Because they’re designed without traditional beams across the bays, drive-in racks allow fork trucks to drive directly into the front of a storage bay, place a load in the designated position then back out. Pallets rest on side rails that run along the inside of the bay, perpendicular to the aisle rather than cross beams, leaving the face of the bay open. The uprights are typically tied together at the top of the upright to add rigidity to the system.
Each bay is typically dedicated to a single product, so drive-in racks are best used for densely storing large quantities of the same product. They work well where an entire bay of product is moved at once, such as in staging product for shipping.
This style of rack is commonly configured to store loads four or more deep, and commonly use 6-8 pallets deep per bay. This helps store even more products ready to be moved. In a “four high and five deep” configuration, a drive-in rack can hold 20 pallet loads in each bay!
The only difference between drive-in and drive-through racks is the location of the entrance. Drive-In Racks have an entrance at only one end, while drive-through racks have entrances on both ends. This changes how fork trucks can organize their loading.
Drive-in racks are organized in a “last-in/first-out” method. The fork truck elevates a load to the proper level and load it in the back of the system first. The second pallet will be placed in the second position from the back and continue until a lane is full. In contrast, drive-through racks typically use a “first-in/first-out” organizational system.
Gravity flow racks combine a stationary rack structure with skate wheel or roller conveyor to create a dynamic storage system. Pallets are loaded into the back end of the rack then travel down the slightly inclined lane of conveyor so they can be retrieved from the front of the system.
Flow rack systems provide high-density storage by storing product many pallets deep. Because each layer of flow rack is typically dedicated to a single product, these systems offer less storage flexibility than selective racks but more than drive-in or drive-through racks.
This is a good option for storing dated products because it allows easy rotation of inventory on a first-in/first-out basis. It can be used for picking by the piece, carton or pallet. Carton flow racks that store individual cartons are also available from Yankee Supply.
Push-back racks combine a stationary rack structure with nested carts that move along inclined rails. The first pallet, which is loaded from the front, is placed on top of the cart. When the second pallet is loaded, it pushes back the first pallet, exposing the second cart, and so on.
Usually configured two to five pallets deep, these systems offer dense storage, but less dense than drive-through racks. Like flow racks, push-back racks do not require a lift truck to enter the racking structure or require an entire bay to be dedicated to one product. But unlike flow racks, push-back racks manage inventory on a last-in/first-out basis and requires less space than flow racks because rear access is not necessary.
