Selective Rack

This type of rack is commonly referred to as “pallet rack.” Roll-formed generally uses a drop-in style connector such as “tear-drop” or “keystone” style and is most widely used because of flexibility and low cost. Bolted, structural is popular in food warehouses and other very high traffic environments. Each pallet is accessible in this type of rack with the density of storage is least. However, this lower density can be compensated for by use of very narrow aisle forklifts.

Drive-In Rack

Allows dense storage pattern but with very limited access to specific loads. Commonly used in food warehousing where complete truckloads of a single SKU is stored and retrieved in “bulk” from a section. Drive thru is a variation allowing a forklift to drive in one side and out the other. This is not in very wide use and its practicality is questionable.

Because forklifts enter the rack, it is important to consider forklift specs when planning the layout. A minimum of 4” clearance on each side of forklift is recommended. Depth of rack is also an issue due to “tunnel” effect on a free-steering lift truck. Pallets must be uniform in width and because this style of rack is not easily adjusted, length & load height should be somewhat uniform. To save cost of modifying the overhead guard on a forklift, explore the possibility of double stacking the floor load as the height of 1 st rail setting usually will be higher than the overhead guard on a forklift.

Cantilever Rack

Commonly used for storing dimensional loads. Because this style rack can be decked, some furniture warehouses will use to store sofas, bedding, etc. A standard arm will generally have a slight incline when not loaded to accommodate for flex when loaded. Each arm bears an equal portion of the overall weight. This rack can be assembled with arms on one side or both sides and does not need to be “tied-off” to another structure. For outside storage, a roof can be added and a concrete pad should be poured.

Push Back Rack

Utilizing selective rack frames and beams this type of storage is an ideal solution to obtaining denser storage within current building structures. Nested carts on rails is the most common configuration and generally run up to 6-deep. This style of rack can be referred to as semi-selective as pallets are always retrieved from the aisle and only the pallet(s) in front of load to be retrieved needs to be removed. Many times this layout allows for continued use of larger counterbalanced trucks while adequately increasing storage. A level of first-i/first out can be achieved through use of a good inventory management system.

Flow Thru Rack

This allows for true first-in / first-out inventory management. these systems can be fairly deep with proper set-up of side guide rollers. Wheels with self-braking properties or rollers with brakes control the flow. Loads weighing less than 1500 lb. may have a tendency to get hung up on a brake zone and pallet bottom boards that are broken will not flow well, or at all, in most systems. Soft wood will take a “set” if stored too long in one position.

Vertical and Horizontal Carrousels

These forms of storage are very useful in high thru-put environments. Shelves or trays are brought to the picker through key-pad commands. Very dense storage and the ability to control inventory are key benefits. These units are much costlier than the other forms of storage but this is generally outweighed by the density and efficiencies afforded. A thorough study of operational requirements is necessary to properly specify design parameters prior to this investment.