Get the most from your VNA storage

Efficient use of space has always been important in distribution centers. But with the cost of industrial real estate going nowhere but up, facility managers are trying to get the most out of their existing footprints, or new facilities. That’s why very narrow aisle, or VNA, storage is topping many people’s lists. Not only can you shrink the traditional 10-foot width of a reach truck aisle, says Christopher Grote, marketing product manager for Class II products at Crown, but you can extend the rack height to 56 feet—much higher than conventional reach trucks—to take better advantage of the cube.

New VNA turret truck technologies, capabilities and applications mean that VNA storage is not only more efficient, but the operations are more productive, Grote adds. “When we think about VNA, you not only want to better use your space, you want to increase throughput,” he says. “You look at travel speeds, lifting speeds, traverse speeds, lowering speeds and pivoting speeds. Those five together are going to heavily impact your overall productivity.”

“Automated fencing and positioning technologies” available on some of today’s trucks provide a level of semi-automation that can promote safety and determine the most optimal path, and speed, to automatically take a driver from Point A to Point B. Auto-positioning technology controls the truck’s blend of lift and travel to optimize the time and energy required to reach and automatically stop at the rack location.

Drivers resume control of the vehicle once they arrive at the pick or putaway location. With auto fencing, speed and height zones can automatically be programmed for safer operation. For instance, the truck may only be able to lift to a certain height in an area with an overhead obstruction, like an HVAC duct, or travel only so fast where there’s pedestrian or lift truck tunnels in the application. “I’m only impacting productivity in areas where’s it’s necessary, based on the needs of the facility,” says Grote.

Another important development, especially in applications like a freezer where storage density is important to control temperature, is the combination of a turret truck with pushback and flow rack to a pick module. On one side of the VNA aisle is pushback rack. On the other side of the aisle is pallet flow rack that feeds a pick module, with additional pushback or selective racking above.

The pushback rack provides efficient reserve storage, while the flow rack feeds the pick face. When a pallet is empty, the order selector removes it, allowing the pallets behind it to move forward. That signals to the turret truck operator to replenish the back of the flow rack from the pushback rack.

“Historically, it’s been unconventional to see a turret truck operating with both flow and push back rack. But in an application where density means everything, it’s a very effective use of space,” he says.

Grote adds that the concept could be applied to various types of pick modules, including floor only (using pallet rider trucks) or even a multi-level pick module (using conventional order pickers).