In a conventional warehouse layout, storage racks are laid out to create rows of parallel picking aisles with perhaps one or more cross aisles in the center. The alternative design, meanwhile, features V-shaped diagonal cross aisles that can improve order-picking travel times by 10 to 20 percent.
The concept was created by Russell Meller, professor of industrial engineering at the University of Arkansas, and Kevin Gue, an Auburn University engineering professor. Generac Power Systems recently put the new design into practice in its Whitewater, Wis., warehouse.
"The main insight behind this design is that a cross aisle that cuts diagonally across the picking aisles affords an advantage in that it allows pickers to get to many of the picking locations more quickly via a more direct route," said Gue.
With the new system, Generac has enjoyed improved material flow and reduced travel distances. Additionally, workers no longer need to turn 90 degrees to enter the picking aisles, and can instead execute 45-degree turns at greater speed and without compromising safety. Additionally, distribution centers that use the efficient system can more quickly deliver items to customers.
"Our results suggest that for unit-load warehouses, radically new designs could lead to faster retrieval rates and significantly reduced costs for operating distribution centers," said Meller.
Safety Considerations
According to Meller, workers at Generac initially were uncertain about the system, especially when they considered whether a new design would have safety implications. But Meller pointed out that in this case, the improved layout could help workers increase productivity without incurring extra risks. Generac also installed safety mirrors at key intersection points to help workers safely navigate the layout.
“They can make the turns, they’re still safe for them, and their productivity increases,” Meller told OccupationalHazards.com. He added that on average, the new design “allows up to a 20 percent reduction in the time it takes to drive to all the locations” in the warehouse.
One safety consideration shared by workers included the possibility for congestion at the bottom of the “V.” With various paths ending in the same location, employers should be aware that the busy intersection could be a potential concern, unless they take proper precautions.
“We usually recommend that people clear our a few extra pallet locations to open it up,” Meller explained. He added that while the new design can be beneficial for many facilities, “these designs are not for every warehouse. You have to meet certain conditions.”
Generac, for example, was aided by high visibility in the warehouse. The company’s product does not take up the full opening of the rack, so drivers can look through the racks to see people in other aisles.
“For what we do, the layout works really well,” said Brian Randelman, Generac’s logistics manager. “We have racking in the middle section, between the diagonal aisles, and floor storage below the diagonals. That gives us the flexibility to adjust to changing operating conditions in the future.”