There are several types of warehouse racking systems, which also are known as pallet racks or materials handling systems. Wooden, metal, or plastic pallets, or skids, are combined with larger racking systems comprised of shelves at various levels. Decking bases are available in different widths to support objects placed on the racks in storage. In many cases, warehouse racking is several feet high and requires forklifts for the loading process. Various warehouse racking system configurations are possible including selective racks, drive-in or drive-through racks, push-back racks, and flow racks.

Selective Racks – The most commonly used pallet system, selective racks provide access from an aisle. These warehouse racking systems are ideal for narrow aisle racking, standard systems, and deep-reach systems. Selective racks require special narrow lift trucks and accommodate a single pallet in depth.

• Drive-In and Drive-Through Racks – For high-density storage, drive-in racks and drive-through racks are ideal. Constructed of steel in most cases, these warehouse racking systems have enough space for a forklift to move into its bay. It’s important to note that drive-in racks have one entrance and exit, but drive-through racks allow access on both sides of the bay. As a result, drive-in racks are suited to the last in, first out (LIFO) process commonly used for nonperishable products or those with a low turnover. On the other hand, a drive-through system requires a first in, first out (FIFO) process. Drive-in and drive-through racks may be floor-to-ceiling structures
• Push Back Racking Systems – Typically used for bulk storage, push back racking systems store products that span 2-5 pallets. When a pallet is loaded onto the system, it pushes the next pallet back, and when a pallet is unloaded, it is pushed to the front of the system. Push-back racking systems utilize the LIFO system and often feature inclined rails and sliding carts and double lanes
• Flow Racks – Also known as gravity racks, flow racks are commonly used for high-density storage. With this type of warehouse racking system, items are loaded at the higher end and removed at the lower end using a FIFO system. The rotation of products becomes automatic as the racks flow with loading and unloading. Flow racks make use of gravity rollers that move in conjunction with the rack load and feature brakes or speed controllers to regulate item movement. One advantage of flow racks is they do not require electricity for operation because gravity powers them