Last week in we focused on the changes to the pallet rack industry and the impact these changes have had. To read that article, visit MULTICHANNEL MERCHANT.
This week we look at what to consider when buying rack systems.
Application engineers have traditionally been the resource used to match the proper rack products to the client’s application or operation. There is a wide range of pallet rack products available, and each manufacturer has unique features designed into its products that benefit each client differently.
To properly select the correct rack system, the application engineer must first identify the characteristics of the load or the product to be stored. What is the size and weight of the load and pallet? Is the product confined to the pallet, or does the load overhang the pallet? If the pallet rack is sized based only on the pallet, a pallet with an overhanging load may not fit in the rack system or in back-to-back rows. Ignoring the overhung load in the design may cause the “flue” space between rows to be improperly sized. This can lead to a problem where loading a pallet in one row pushes product on a pallet in the adjoining row, creating a safety hazard. Is the load stretch wrapped or loosely palletized? Unwrapped loads may require wire decking on the pallet beams to prevent loose product from falling from the pallet and through the beams.
Are multiple pallet sizes or types used? Varying size pallets or types may dictate the use of pallet safety bars between the beams in a bay. How do the bottom boards of the pallet match with the beams of the pallet rack bays? If the bottom boards of a pallet loaded with 2,500 lb. of product are not properly placed on the rack beams, the boards can be overloaded and could break, causing the pallet and load to fall through the rack openings.
Application engineers will review the type of lift equipment used to load and unload the rack. This will help them determine the proper aisle width based on the turning radius of the trucks. It will also allow them to determine how much lift space is required between the top of a pallet load and the bottom of the beam of the pallet position above.
The size of a rack column is based upon the loading placed on the column as well as the unsupported height. The unsupported height of a column is the space between beams attached to the column or upright. The smaller the unsupported height, the greater load a column will carry. This is critical not only for new systems but also for modifications to existing rack systems. Often operations personnel will “reslot” a rack system, relocating beams or removing beams from the system. If the unsupported height of the column is increased without subsequently reducing the loads imposed on the system by the pallets, the system could be seriously overloaded, resulting in damage or even structural failure of the rack system.
In the distribution centers of today, more and more rack systems are multipurpose racks. A typical application may have lighter beams installed on closer centers on the lower portion of an upright to be used as shelving, while the upper levels use heavier beams for pallet loads. By mixing the types of beams purchased, you can reduce the total cost of the system. Other applications may call for the mixing of a carton flow system with pallet flow systems and “push back” racks as reserve storage above. The best value and design in a system such as this may come from using products from multiple vendors.
Bill Tymensky is vice president for design engineering for Nashville, TN-based supply chain services provider Fortna.