Racks and Storage - Warehouse Design Part 3

by

In our mini-series on Warehouse Design we have been looking at a lot of preliminary and general considerations. In both of the prior articles, the subject of storage racks and shelves have been briefly discussed; in today's article we are going to look at some of the most common options for storage you may encounter in your practice as a 'trusted warehouse and inventory advisor.'

When your client asks if they should be using Carton-flow shelving or Cantilever racks, will you know what to tell them, or even what they are talking about?

Every warehouse needs some 'great racks', they are integral to your warehouse design. Properly configured storage racks and shelving must be considered when you actually layout the overall footprint and internal design of your warehouse.

But the best storage for your warehouse should not be configured based upon space or handling requirements alone. Considerations should be given to the storage density of your products. It is rare to find an efficient warehouse layout with only a single style of storage rack because it is rare to find a warehouse with similar storage density for all of its SKUs.

For example. fast moving SKUs are commonly stored in dense storage configurations,  while medium moving SKUs are often stored in simpler storage configurations. Slow moving SKUs, which can represent as much as 50% of your warehouse capacity, even though they represent only 5% of your sales, typically should be stored in as economical a fashion as possible for the actual SKU (based upon size and weight).

When you use the right storage option, in the best layout possible, you maximize both storage and order fulfillment productivity.

.

Manual Warehouse Shelving and Storage

Manual warehouses typically hold items stored on shelves in quantities that do not require mechanical assistance to be moved about.  Manual warehouses are appropriate if the vast majority of your products are received and stored in packages or quantities that can be easily moved about by hand or with the assistance of a hand cart or dolly. Even in such warehouses some palletized materials maybe present, but these will typically make use of some designated area of floor space. In these instances, manual ‘hydraulic pump’ pallet trucks can be used to move about, off-load and on-load palleted goods. These warehouses may make use of rows of shelving for either goods to be stored in bins, or within packaging. The top shelf in most configurations ranges from 66 to 84 inches in height, and packaging typically weighs no more than 40 to 50 pounds.

In these warehouses the vast majority of products are unpacked upon receipt and transferred to bins, shelves and rows based upon the overall inventory schema. In some situations cartons or cases, in whole or in part, maybe stored using carton-flow racks designed to segregate 'picking' from 'stocking' and also facilitating FIFO (first-in, first-out) inventory management.

Wide Span Shelving is designed for the hand-loading of medium to heavy loads and is ideal for storing small quantities of a large variety of product types. Wide Span Shelving can be adapted to meet a variety of hand-stack storage requirements. In some cases, shelving of this type can be configured to work with stairs and catwalks to create multiple levels of storage thus maximizing your warehouse height. Advantages include:

  • Quick and easy assembly 
  • Can be adapted to a shelving module for any load configuration
  • Configurable with galvanized steel shelf panels, reinforced wire decking, hanger beams for storing textiles and clothing, or particle board

Carton Flow Racks are designed to separate the picking and stocking aisles within a warehouse. These racks are more like ‘installing a system’ than simply ‘storage racks’. Made up of slightly inclined wheel and roller platforms, the goods are deposited at one end to slide safely and gradually down to the picking aisle thus permitting your picking functions to remain clear of your restocking functions. When used for full cartons and split cases a typical warehouse can save significant labor costs compared to static storage solution. This shelving is perfect for first-in/first-out (FIFO) inventory and minimizes product shelf time to keep inventory fresh.  This storage is ideal for a wide range of warehouses and can be used for storing mass consumer goods to pharmaceuticals, cosmetics, computer components and more.

.

Mechanized Warehouse Racks and Storage

Mechanized warehouses are designed around modern methods of storage and materials handling; typically, these warehouses have tiers of pallet racks, perhaps 40 or more feet high. Mechanized warehouses are needed if a large percentage of products will be received and stored on pallets. The use of pallets as the primary storage schema in the warehouse requires powered forklifts, or other equipment, designed for moving pallets within the confines of the warehouse design. In many instances pallets will be stored on both the floor and on pallet racks.  While pallet standing/block stacking maybe used in some smaller warehouse environments, the overall efficiency and handling of pallets can limit inventory control functionality. For example, if you use FIFO (first-in, first-out) for inventory, you typically find that the ‘first in’ pallet is now on the bottom of the stack, thus requiring a re-stack to execute orders. The same may apply if you use FEFO (first-expiring, first-out) as part of your quality control directed handling of product. In either of these cases you are best to design the warehouse to make use of pallet racking rather than stacking.

Mechanical equipment is used for handling the unloading and storage of goods received, and often to load outgoing goods onto delivery vehicles.  The mechanical equipment used in these facilities can range from manual pallet movers to human-operator-forklifts, but in many such facilities computer controlled automatic handlers, like robot controlled forklifts are taking the place of traditional equipment. Since robot forklifts are more ergonomic and space friendly, they easily operate within the confines of smaller spaces; as a result warehouse designs and storage units are being configured with closer isles, which means more isles per square foot, and that means more product stored in the same space.  Some of the 'racks and storage' designs used in today's mechanized warehouses configured for more efficient use of space, manpower requirements and logistics are pallet racks, drive-in/thru storage racks and cantilevered storage.

Pallet Racks are the most popular and versatile racking solutions for warehouse storage. They offer the best solutions for warehouses with palletized products and a wide variety of goods. Advantages include:

  • Direct access to each pallet
  • Simple stock management
  • Adaptable to any product volume, weight or size
  • Save costs by using Wide Span beams with selective end connectors

Pallet Racks can be configured for a variety of uses. One option is double-depth racks which increase storage capacity by enabling four pallets to be stacked back-to-back; the only disadvantage of this arrangement is that you will need deep-reach lift-trucks for loading and unloading. Some rack forms can used in the construction of rack supported buildings as well as for more basic storage needs.

Drive-in/Drive-Thru Pallet Racks are ideal for stocking large quantities of relatively few product types. Their use can reduce overall square footage requirements by 35 percent or more compared to a standard Pallet Rack configurations. Drive-In pallet rack systems use the same entry and exit point for each storage bay, providing last in, first out (LIFO) access. Drive-Thru pallet rack systems can also be configured for loading on one side and unloaded from the other side thus permitting first in, first out flow (FIFO) access. Advantages include:

  • LIFO/FIFO (last in, first out/first in, first out) configurations
  • Reduces space, cuts cost, and holds more loads with its deep lane storage
  • High volume, low SKU
  • Eliminates the need for multiple aisles
  • Provides control over entry and exit
  • Favors density as opposed to the selectivity of standard Pallet Racks
  • Configuration and layouts are designed to suit your pallets and lift-trucks

Cantilever Racks are the storage solution of choice for long or bulky items like steel pipe, steel plate or bar, PVC-pipe or tube, and other bulk materials. Cantilever Rack should be designed, engineered and organized for strength, stability and safety. Advantages include:

  • High degree of customization and configuration
  • Wide range of load capacities suiting a wide-variety of storage applications
  • Center column design creates unlimited horizontal space
  • Adjustable vertical arms for maximum versatility

.

Conclusions

As trusted warehouse and inventory advisors you need to be familiar with a wide variety of storage options for both manual and mechanized warehouses. This article serves as only a brief introduction of these concepts, you need to thoroughly study all the options, visit with multiple 'racking' providers, and inspect as many warehouse layouts as you possibly can in developing your expertise.

That way, when your client asks if they should be using Carton-flow shelving or Cantilever racks, you may still not know exactly what to recommend, but you can provide as many detailed options as possible to help them make such decisions, because you at least now know what they are talking about.