Racks

In addition to the many styles and manufacturers of rack, there are several types of rack, each with its own advantages and limitations. Types include: Selective Pallet Rack, Double Deep Rack, Drive-In/Drive-Thru Rack, Push Back Rack, Pallet Flow Rack, Carton Flow Rack and Cantilever Rack.

Selective Pallet Rack

Selective pallet rack is what most people think of when they talk about rack. It is the most common and gives you complete selectivity. Each pallet is stored in its own location and is available via a forklift. Selective rack is good when you have a lot of different SKUs and not a lot of pallets of each SKU. It is the least cost per pallet position of any rack type. The limitation of selective rack is that the complete selectivity requires a lot of floor space. Each row requires a forklift aisle to access it and depending on the type of forklift, a lot of valuable floor space can be taken up for forklift access and not inventory. Selective rack is very common in big box retailers or warehouse clubs.

Double Deep Rack

Double deep rack is standard selective rack, but there is one row of rack in front of another. A special double reach forklift is required to pantograph through the front bay to access pallets in the rear bay. The advantage is that you get 2 pallets deep of storage for every forklift aisle instead of 1 like standard selective rack. Disadvantages are that double deep has a tendency to create honeycombing which is having pallets in front position, but not in rear position and it requires a special forklift.

Drive-In/Drive-Thru Rack

Drive-In rack is high density, low selectivity storage. For companies with many pallets of the same SKU, drive-in/drive-thru rack is the least expensive option. Systems can be 2-deep on up. Advantages are that it stores many pallets in a high density layout, requires fewer aisles and is ideal for customers with a lot of pallets of the same SKU. Disadvantages are that forklift operators are required to drive into the rack system and it has limited selectivity. Drive-in also has the disadvantage of having LIFO inventory utilization. Drive-thru has a disadvantage over drive-in in that it requires an additional forklift aisle.

Push Back Rack

Push back rack is another high density storage option. Push back is available in 2 thru 5-deep applications. Push back has more selectivity than drive-in/drive-thru. Pallets are all accessed from the front bay. Pallets are generally stored on a cart system where all pallets index forward when the pallet in the front position is removed. Advantages are that it is high density storage, has greater selectivity, utilizes less forklift aisles and requires less pallets of same SKU than other high density options. Disadvantages are that it has LIFO inventory utilization in each lane and cart system may reduce number of pallets that can be stored in height. Push back costs more per pallet position than drive-in/drive-thru

Pallet Flow Rack

Pallet flow rack is very high density storage and has FIFO inventory utilization. Pallets are loaded on one side of system and convey forward to discharge end after a pallet is removed. Each system requires two forklift aisles. One aisle is for loading and one for unloading. The biggest disadvantage is the cost. Pallet flow usually requires the largest capital outlay, but for the right application, savings in operations can produce a quick ROI. Pallet flow is very popular in food applications where shelf life is critical and FIFO is the name of the game.

Carton Flow Rack

Carton flow rack is for exactly what the name implies, flowing cartons in lieu of pallets. Inventory is loaded from one side and flows to the pick side. Carton flow rack is accessed by employees walking down aisles picking products by hand and not on a piece of equipment. Carton flow rack can be used to pick cartons and also has the ability to do open case picking where less than carton quantities are required. Carton flow rack can be used in standalone units or as part of a pallet rack or pick module system. Carton flow rack is only good for carton quantity applications.

Cantilever Rack

Cantilever rack is used where long, bulky items are stored. Cantilever rack is common in storing wood, pipe, PVC, steel, and furniture among other items. Cantilever rack comes in single-sided and double-sided. Each side requires a forklift aisle.