Filling the Footprint
Connect, Summer 2007

Minimizing space requirements while maximizing space utilization yields a more productive DC

It’s not always easy to find space in your distribution center (DC) for both product and processes, but having enough room to store and handle SKUs is critical to maximizing efficiency. To relieve congestion while cost-effectively utilizing the space inside the box, it’s important to find a balance between optimizing storage density and maximizing flexibility, says FORTE’s Jerry Vink, vice president of engineering.

“To increase productivity without expanding the facility’s footprint, space-consuming practices and procedures need to be addressed,” he notes. “The solution requires a two-prong approach: minimize space requirements and maximize space utilization.”

Minimizing Space Requirements

While the value of a warehouse management system (WMS) is widely understood, a common pitfall is failure to maintain the information within the system, generating wasted space. Keeping product item master information current—such as product dimensions, pack quantities and pallet sizes—affects putaway logic, storage rules and slotting.

In a tight warehouse, partial pallets and fractionally-filled storage locations can be combined. Although this practice is often not considered value-added work, consolidating bulk stack pallet locations as product moves out and relocating partial pallets to smaller locations can relieve some pressure when space is at a premium.

“If first in/first out (FIFO) rules can be bypassed, partial pallets can either be directed to pick locations, or pick locations can be replenished with those partials first,” suggests Vink.

Two more space hogs: excess inventory and obsolete SKUs. Excess inventory is hard to manage and harder to prevent when facing rapid demand changes. Working with suppliers to schedule smaller, more frequent deliveries is one solution to curbing overages. And, if a discontinued SKU wastes precious space, it should go.

Product slotting in pick areas—through either expert analysis or software applications— manages the location of SKUs based on dimensions, weight, pick velocity and family groups (style, store or vendor). Based on the product’s cube velocity, storage media optimization determines both the ideal equipment (pallet, shelving, flow rack, etc.) and the amount of space required within the equipment. Like the WMS, maintenance of the underlying data analyzed by the slotting optimization system is key to realizing the most efficient storage of SKUs.

Maximizing Space Utilization

Most DC managers have no problem filling every possible floor opening. “However, they may not use the floor space efficiently, or not use the height of their buildings effectively,” observes Vink.

Although it eliminates flexibility, one way to maximize floor space is block stacking several pallets deep and wide of stable, firm product up to four or five levels high. The product must be right for the application, FIFO or lot control must be considered, and ongoing consolidation to generate floor space for other products over time is required. Similar issues arise with other space-saving storage equipment, such as pushback and double deep rack.

On the flip side, selective rack offers direct SKU accessibility, making it the most flexible—but least dense—solution for vertical static storage. After ensuring that beam and upright capacities can handle the additional weight, you can maximize its density by building it to levels as high as practical. For example, six levels yields 50% more space per square foot than four levels. Integrating a limited number of storage locations within the selective racking for short or partial pallets increases storage with minimum impact on flexibility.

Although varied in both storage density and equipment costs, reducing aisle widths from standard to narrow-aisle or very-narrow-aisle (VNA) widths offers a net gain in storage space. An automated solution, like a mini-load or a pallet automatic storage and retrieval system (AS/RS), uses aisle widths similar to VNA and has the potential for higher storage heights. Inventory stored in such aisles can be controlled and optimized by the software running the system. This software may relocate loads to minimize retrieval times or to balance work across aisles with no human intervention.

While you’re looking up, consider hanging non-storage-related equipment, such as conveyor and void-fill systems, from the ceiling to free up floor space and improve forklift traffic flow and safety, offers Vink. Spiral conveyors and vertical lifts are useful substitutes for incline conveyor when horizontal space is limited due to proximate aisles.

Mezzanines, particularly over dock and staging areas, are also effective ways to free up floor space and improve the flow of personnel and traffic. These raised work areas can be used for office space, value-added services, conveyors and storage of supplies.

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