Pallet racking systems are crucial to warehouse storage, allowing you to maximize the efficient use of available floor space. When you’re searching for racking systems, however, the number of styles available can be overwhelming.
By identifying your requirements, you can determine the best storage system for your warehouse. Used racking offers a relatively low-cost alternative for the budget-conscious warehouse manager. You will need to perform due diligence when considering used racking systems.
What is Warehouse Racking?
A warehouse rack comprises upright steel frames, consisting of two posts or columns each, reinforced with horizontal or diagonal bracing struts. Horizontal steel beams connect these upright frames.
Workers place pallets on the beams between the upright frames. Two frames and beams comprise a single bay. The number of pallets that your racking system can store depends on the height of the frames and the width of the beams. For increased stability, racks are often also equipped with foot plates that allow you to anchor the rack directly to the concrete floor of your warehouse.
It’s important to distinguish racking systems from shelving units. Although warehouses can use both, racks are designed for storing pallets or other materials for retrieval by material-handling vehicles, such as forklift trucks. Shelving units are designed to store smaller items and to be accessible to order pickers working on foot.
How to Choose Warehouse Racking
In the process of determining which type of racking system is best for your warehouse, you’ll need to evaluate your requirements. The factors you’ll need to consider include the quantity and weight of pallets or other materials, number of SKUs (stock-keeping units), and inventory turnover and rotation method.
Inventory or stock rotation methods include the following:
FIFO
In the FIFO, or first in, last out, method, the first pallet or inventory item that a worker loads into a racking system is also the first to be retrieved. Warehouses and other businesses use FIFO for items with a short shelf life, such as perishable food items, to avoid spoilage. In addition, products with a high turnover rate are often stored and retrieved on a FIFO basis.
LIFO
In the LIFO, or last in, first out, method, the last pallet or inventory item that a worker loads into a racking system is the first to be retrieved. At the same time, the first item stored will be the last item retrieved. LIFO is appropriate for goods that are homogeneous and don’t expire or depreciate with age. LIFO is inappropriate for time-sensitive goods that must be retrieved and distributed quickly.
Used Racking Systems
Regardless of the type of pallet rack you choose for your warehouse, used racking requires careful evaluation. A reputable supplier inspects used racking for defects, signs of wear or damage, and deflection.
Types of Warehouse Pallet Racking
The most common types of warehouse pallet racking include:
Selective racking
The first and most common type of storage rack is the selective pallet rack. Relatively inexpensive and operating on a FIFO basis, the selective rack is ideal for the low-volume storage of diverse products in which access to multiple pallets and SKUs is vital.
The selective pallet rack is available in various configurations, load capacities, and sizes to suit your storage needs. In addition, selective racks are compatible with standard forklift trucks, so you don’t need to hire or purchase specialized material handling equipment.
Push-back racking
Push-back racking is a LIFO system designed to provide both high-density storage and selectivity. Pallets are placed on nested carts that move along inclined rails.
When a forklift truck loads the first pallet into the system, it places it on the top cart. When it loads the second pallet, it pushes the first pallet rearward, exposing the second cart for loading. When a pallet is retrieved, the pallet behind it moves forward into position.
Unlike pallet-flow racking, push-back racking uses the same aisle to load and unload, requiring less floor space. Push-back racks can be two to six pallets deep.
Pallet-flow racking
Pallet-flow racking is a high-density FIFO storage system that uses inclined roller lanes to transport pallets from the rear of the rack to the front face for retrieval. This is considered a live or dynamic system, as gravity assists the flow from the loading or charging aisle to the retrieval or discharging aisle. Pallet-flow racking is in some ways the opposite of push-back racking.
Drive-in racking
Drive-in racking is a high-density system that allows forklift trucks to enter a storage bay to load and retrieve pallets on a LIFO basis. When the truck has placed a pallet in the desired location, it exits the rack by reversing. In order for a forklift truck to enter a storage bay, drive-in racks do not use traditional horizontal beams. Instead, pallets rest on rails that run the length of the racking system.
When using drive-in racking, each bay is usually assigned to a single product. As a result, drive-in systems are ideal for the high-volume storage of homogenous products. Drive-in racks also eliminate the need for external aisles, significantly increasing storage capacity compared with other racking systems.
Non-Pallet Racking
For warehouses that need to store non-palletized raw and finished materials such as lumber and bar stock — tubing, piping, steel rods, and furniture, you need a different approach.
Cantilever racks
Long, heavy, or awkwardly shaped items can pose a challenge for traditional racking systems. Cantilever racks are designed to support cumbersome inventory on a set of arms that attach to upright frames via bolts. The frames attach to horizontal bases in single- and double-sided configurations. The base provides stability to the racking system and supports the bottom load. Cantilever racks are relatively low density but allow for a high degree of selectivity.
At Shelving + Rack Systems, Inc., we supply cantilever racks ranging in height from eight to 20 ft. with a weight capacity of 8,000–11,000 lb. For increased corrosion resistance, our cantilevers are galvanized, making them ideal for outdoor applications and adverse conditions.
U-Racks
Our U-Racks offer a modular and affordable storage solution for bar stock, piping, and tubing that doesn’t take up much floor space. Consisting of interlocking steel frames, you can stack up to four U-Racks, one on top of another. The double-welded steel construction ensures a high degree of strength, providing a weight capacity between 6,000 and 10,000 lb., depending on the variant. Furthermore, the orange enamel finish protects the steel racks against corrosion. If you intend to stack our U-Racks, keep in mind that cross-variant interlocking is not possible.
Carton Flow Racking
Carton-flow racking is a high-density, dynamic storage system designed to transport small inventory items, such as cardboard boxes, on gravity-fed rollers from one aisle to another.
Roll Formed vs. Structural Racking
Warehouse racking systems are available in two fabrication and assembly types:
Structural
Structural racking comprises hot-rolled steel uprights and beams that are bolted together during assembly. Designed for heavy-duty applications, structural racks have higher load capacities than comparable roll formed racks, owing to their high-gauge steel construction.
As structural racks are heavier, they’re more expensive to ship. Aside from load capacity, the increased strength of structural racks is also more resistant to impact damage from forklift collisions. Consequently, if you need racks for high-traffic warehouses, structural racking is generally preferable.
Roll formed
Roll formed racking comprises cold-rolled steel uprights and beams. Relatively lightweight and inexpensive, roll formed racks use teardrop-shaped holes for connection and assembly. This assembly method only requires the use of a mallet, simplifying installation and later adjustment. As roll formed steel is lighter than structural steel, it’s less expensive to ship.
Roll formed racking is adequate for most warehouse applications. However, the light-gauge construction is not as strong or durable as structural racks. One way to increase the strength of the system is to use tubular uprights.
Ways to Minimize Damage Risks
There are several ways to minimize the risk of damage and rack failure in your warehouse. Identify potential risks. If your forklift drivers are inadequately trained, or your warehouse fosters an unsafe work culture, these are areas that you should address.
Aisle Space
If there are aisles between your storage racking systems, the aisle width must provide adequate clearance for forklift trucks to maneuver. Aisle widths have become increasingly narrow as forklifts have become more compact; however, you should still consider the space needed by drivers to navigate racking systems safely.
Inspections
Conduct regular inspections of your warehouse racks to ensure that the upright frames have not incurred damage from forklift collisions. If you identify damaged uprights, log this information and determine whether repair or replacement is necessary.
Netting
The uprights are not the only parts of a racking system that can experience damage from forklift impacts, seismic activities, and other phenomena. If pallets fall off racks, this can pose a hazard to workers on the floor and cause inventory loss.
One way of reducing the risks associated with pallets falling is to install load containment netting. Netting allows you to ensure that pallets don’t fall off racks while also increasing airflow and visibility compared with other barriers.
Column Protectors
Don’t neglect the importance of column protectors and guard rails for protecting uprights against forklift damage. Forklift collisions are one of the primary causes of damage to racks. These steel guards absorb impact, preventing the uprights from becoming deformed. If the rack’s uprights experience deflection from impact, this can weaken the structural integrity of the rack, increasing the chance of collapse.
Where to Buy Used Racking
At Shelving + Rack Systems, Inc., we supply a wide variety of racking and shelving systems designed to maximize storage space, increase retrieval efficiency, and improve throughput rates.
If you’d like to discuss your options for used warehouse racking, give us a call at (800) 589-7225.
