Carton Flow 101: The Advantages of a Gravity Flow Rack

Storage is important in any warehouse. It helps to understand the difference in storage offerings when you are looking for a solution. Is static storage sufficient or will your business benefit from gravity flow rack storage? Let’s look at the difference.

Static storage is often traditional pallet racks and shelves for holding products in storage. They are designed to hold materials on pallets in horizontal rows on multiple levels. They are relatively inexpensive, which is why they are popular, yet the labor to stock and pick from the shelves is more extensive, requiring more time from workers. Forklift trucks are often used alongside this type of storage to place the loaded pallets onto the storage racks.

Besides the low cost, static racks can be configured to reach from floor to ceiling, using a variety of shelving, from wire shelves to wood. With adjustable shelving, you can reconfigure, dismantle and reuse the shelving elsewhere.

However, static storage can create several points of pain in an order picking operation. Because product does not flow forward to the point of pick, workers must spend extra time and energy retrieving product from the back of the rack- or store the same product at several pick facings. This creates a product footprint that is vastly oversized, wasting space in static racks and contributing to what we like to call “storage sprawl.” Storage sprawl negatively affects the efficiency of order pickers. Statistics show that workers waste 85 percent of their time walking and searching for products within warehouses using static storage methods. If there is a static storage area in your warehouse, are workers wasting steps looking for items to pick?


Gravity flow racks are characterized by their gravity feed rear-load design. Merchandise is stocked in the rear and moves forward toward the picking area in front on an inclined shelf equipped with roller track. When a carton is moved from the front of the rack, the next carton slides forward in its place. Items are always and easily in reach of pickers and do not require multiple pick facings, drastically reducing “storage sprawl.” Inventory is easy to monitor, as products are fully visible. Because items are picked from the front and stocked from the rear, restocking and picking can be performed with minimal travel and greater efficiency.

With carton flow rack systems, labor savings of up to 75% can be realized as stocking speed in often doubled or tripled. These systems also take up less floor space because fewer aisles are needed to reach the same amount of products. Gravity flow racks present a larger number of SKUs to the picker in a smaller area, improving efficiencies.

On the downside, many gravity flow racks do not offer the opportunity to store pallets above the rack. However, UNEX has engineered several solutions for pallet picking and partial pallet picking in order to alleviate the need for a pallet position above a gravity flow rack.

Depending on what you need in your warehouse, UNEX Pickologists will learn your requirements and suggest the best storage system for your needs and budget. If you’d like to discover the optimal storage method for your facility, contact us today!