Coming to Terms with the Material Handling Word Soup – Pallet Rack Glossary
Apex Shares Helpful Pallet Rack Glossary
While no business is immune to confusion and mistakes due to miscommunication, we find that common terms and phrases are anything but common in the material handling & warehousing sector. Given that the average facility has potentially millions of moving parts, it’s critical that your team rely on a single set of terms to ensure successful communication, which leads to increased safety, efficiency, and, ultimately, cost savings.
Since Apex is heavily immersed in pallet rack design and warehouse safety training, we thought we’d share the Pallet Rack Glossary of Terms that we use to train our team. We’ve also included useful links to product pages and blogs should members of your team need training or a refresh of common warehousing systems terms and abbreviations.
Please let us know if you have regularly used terms that you think would be good to add to our Glossary. We welcome your feedback. If you’d like to discuss system design or operation to solve your facility or inventory challenges, give us a call… we’re trained and always ready to help!
Pallet Rack Glossary of Terms
Accumulation Conveyor: Allows items to move along the conveyor while temporarily accumulating or pausing at specific points without causing collisions or disruptions in the overall flow. This controlled accumulation regulates product flow and prevents bottlenecks.
Automated Guided Vehicles (AGVs): Self-propelled, robotic vehicles equipped with sensors, cameras, or lasers that enable them to navigate autonomously and safely through a warehouse or manufacturing facility. AGVs can transport goods, pallets, or containers from one location to another, following pre-programmed routes or reacting to real-time environmental changes.
Automated Mobile Robots (AMRs): Autonomous robotic systems equipped with sensors, cameras, and advanced navigation technology, designed to perform tasks and navigate in dynamic environments without needing fixed infrastructure like tracks or guide wires. AMRs can transport goods, perform inventory management, pick and place items, and execute various other tasks. They are adaptable and can be integrated into existing workflows.
Automated Storage & Retrieval Systems (ASRS): Advanced warehouse solutions that use robotics, computer software, and machinery to automate storing and retrieving goods. They efficiently handle inventory management, maximizing storage capacity, and streamlining operations. Scalable options include semi- and fully-automated systems.
Back-to-Back Rack: Refers to a formation where 2 pallet rack uprights are installed back-to-back. The backs of each system are secured together using row spacers. (See also: Deep-Reach (below))
Bay: Common term referring to a section of rack or shelving where a pallet, for example, would be stored.
Box Beams: A type of shelf beam created without an inset step… has four flat sides like a box.
Carton Flow: Pallet rack system configured to accommodate deep-lane storage of cartons, totes and eaches. A gravity flow system relies on slightly inclined beds of wheels or rollers to glide inventory from load end to pick end.
Cantilever Rack: Storage rack system designed for storing long items, such as lumber, building products, furniture and even wire rolls. Rack is distinguished by protruding arms attached to the rack column where items are placed for storage.
Column: A column can be the front or rear vertical structure for an upright. It can also be the independent vertical support (mono-post) in a pushback, drive-thru, pallet flow, or pallet shuttle upright line. A column can be manufactured in a variety of steel thicknesses and in both structural and roll-formed based on load requirement and usage. Holes or punches run the length of the column at standard intervals where the beams will ultimately be connected.
Connectors: Roll-formed beams are designed to clip or snap into the columns depending on the specific punching pattern of the column. Safety clip-to-column options include a clip, snap or bolt and will vary based on column punching.
Deep-Reach Rack: Refers to pallet rack layout of back-to-back rows of 2-deep selective rack. Double-deep selective rack requires the use of a deep-reach forklift.
Drive-In Rack: Pallet racking designed to allow forklifts to enter into the individual bays of the rack to load and pick palletized material. A popular high-density storage solution.
Empty Pallet Return Lanes: Collect and consolidate empty pallets for reuse or recycling. EPR lanes flow away from busy case pick areas to provide a safe, organized way to manage empty pallets and reduce clutter.
FIFO: Inventory processing acronym for First-In/First-Out describing the SKU storage method used. FIFO product enters the rack from the rear and removal is done from the front so that the first product loaded is the first one to be picked.
Gravity Conveyor: Requires no external power source and relies solely on a slight incline or push assistance to transport goods from one point to another. It is a cost-effective and low-maintenance solution for light to medium-weight materials in warehouses, distribution centers, and assembly lines.
Honeycombing: Refers to empty pallet positions due to insufficient inventory, reducing the overall storage efficiency and potentially compromising safety. High-density storage racking with designated SKU lanes is most vulnerable to honeycombing–particularly Drive-in Rack.
LIFO: Inventory processing acronym for Last-In/First-Out describing the SKU storage method used. The first product picked is the last product that was stored.
Pallet Conveyor: Mechanized conveyor for transporting palletized loads from one point to another consists of interconnected rollers, chains, or belts that efficiently move pallets and streamline logistics.
Pallet Flow: Pallet rack system using slightly inclined wheeled rails or rollers that allow pallets to move smoothly along a sloped plane. A type of gravity flow or dynamic flow rack system, pallet flow often has accessories such as brakes, stops and guides to ensure safe, efficient pallet movement.
Pallet Rack: Material handling storage method designed to store materials on pallets or “skids”. As this guide explains, several options for pallet racking exist with the ultimate purpose of storing palletized inventory in horizontal rows and on multiple levels.
Pallet Supports: Metal crossbars that assure proper load balance and prevent misplaced pallets from temporarily falling through. Pallet supports are often an alternative to wire decks.
Pick Modules: Multi-level, complex racking structures designed to facilitate order picking and replenishment storage in a highly condensed and organized footprint. Pick modules often have pallet racking and a selection of storage applications for faster carton and each pick.
Pick Tunnel: A floor-level pick line surrounded by 2, 3, or 4-deep pallet racking on either side and a covering above. The tunnel is assessable by pedestrian traffic only, and pallets are not stored directly above the pick zone. Forklifts load palletized inventory from the outside lanes — 1st level pallet flow moves inventory into the tunnel, and push-back rack in the upper-level storage positions holds reserve stock.
Push Back Rack: Pallet rack fitted with a series of nested rolling carts that sit condensed at the front of the rack and then expand back as each top cart is loaded with a pallet. Carts move on a slight incline so that they move smoothly back when pushed by the forklift for loading and glide gently forward as front pallets are extracted.
Rack: Describes the steel storage structure of uprights and beams designed to store pallets or other inventory items.
Roll-Formed Rack: A method for producing steel storage rack components; uprights, beams, and struts.
Row Spacers: Used to connect two back-to-back upright rack systems. Row spacers ensure that the rows are kept straight and can provide strength and stability to the rack structure.
Selective Rack: Single-deep, static pallet racking that allows for good vertical space use. It is the most cost-effective storage solution.
Shelf Beam: The purpose of the shelf beam is to connect to the upright columns to form a shelf for the pallet to be placed upon. Box, top, and structural channel are the three types of shelf beams.
Shelving: Describes a multi-level storage unit convenient for hand-stored products as opposed to the rack, which is typically loaded via a forklift or other mechanical equipment.
SKU: An acronym for Stock Keeping Unit, which identifies an individual product in inventory.
Sortation Conveyor: Specialized material handling system that automatically sorts and directs items to their designated destinations. It employs a combination of sensors, diverters, and conveyor belts or rollers to efficiently segregate items based on predetermined criteria such as destination, size, weight, or SKU.
Step Beams: A type of shelf beam that has an inside step along the top inside edge on which to place pallet supports or wire decks
Structural Rack: Pallet rack systems where uprights and beams are manufactured from hot rolled channel steel and structural angle, then welded together to support greater weight-bearing capacity. Beams and columns of a structural system are bolted together. Structural pallet rack can also be designed into the structure of the building itself so that the upright columns are simultaneously used to support the roof of the storage facility, in which case the structural pallet rack uprights replace the storage building’s vertical support I-beams.
Transportation Conveyor: Versatile motorized conveyor that moves a range of item sizes and weights from point A to B. It utilizes belts, rollers, or chains to transport items smoothly, facilitating efficient movement and reducing the need for manual labor.
Unsupported Span: Refers to the horizontal distance between two upright frames in a pallet rack system without any additional support in the middle. It is the clear space between the frames where pallets or loads are stored. Properly determining and adhering to the appropriate unsupported pallet rack span is crucial to ensure the rack’s structural integrity and safety when storing heavy loads. Unsupported spans that are too wide may lead to rack failure or bending, posing significant risks to personnel and inventory.
Uprights: Uprights are typically constructed of two columns connected by horizontal and vertical struts and anchored to the floor via the baseplate.
VNA: Acronym for Very Narrow Aisle. In a VNA system, pallet racks are loaded and unloaded using a side-loading fork truck; therefore, the racks can be positioned at closer intervals minimizing floor space needed for aisles.
Warehouse Slotting: A strategic process of arranging products or inventory within a warehouse to optimize storage space, improve picking efficiency, and reduce operational costs. It involves analyzing item characteristics, demand patterns, and storage requirements to assign the most appropriate storage locations for each product to streamline the order fulfillment process.
Wire Decks: A common safety feature added to selective pallet rack to prevent pallets or individual products from falling through the rack. Wire decks are placed over or in between the beams to basically form a shelf in the rack bay.
