In warehousing, one of the biggest challenges has been increasing the amount of usable storage space without increasing the building's footprint. Many companies have seemingly exhausted all their options. They've started crossdocking some inventory, put storage racks over dock doors and across aisles, cleared out slower-moving SKUs, turned some things over to third-party logistics providers and more, but it's still not enough.
For them, a new mobile racking solution that has proven itself overseas for years is now making its way to North America. These racks promise to increase the amount of usable space in an existing warehouse to about 85 percent.
Mobile racking uses conventional storage racks mounted on trolleys that move from side to side along rails embedded in the floor. The racks are banked together in blocks with no aisles between them. A series of chains and pulleys move the racks to create an aisle only when and where it is needed. Racks move at about 15 feet per minute, meaning that it takes about 30 seconds to open an aisle wide enough for a narrow-aisle forklift to get in and move around to pick or place a pallet.
Rack movement can be directed manually from a push-button control panel or forklift-mounted transmitter or automatically through a computerized processor that can be programmed to interface with the warehouse management system.
"Communication between the racks and the WMS is seamless. The same system that directs a forklift to a specific location within the warehouse sends a signal to the racks to open an aisle," explains Rob Schmit, vice president and managing director of SSI Schaefer's Automation and Systems Division, a mobile racking manufacturer. "While the WMS is telling the driver to go to Aisle 23, the system is opening Aisle 23 so that it is available when he gets there."
Just about any racking system can be converted to a mobile system. "Nine out of 10 standard racks will fit on the system. The mobile racks can hold about 500 metric tons, and they can go 50 or 60 feet high. The only building requirement is that the floor be able to handle them," says Schmit, whose company is based in Germany but has U.S. headquarters in Charlotte, NC.
Mobile rack installation takes about a month to complete. It takes a little more than a week to pour the concrete and install the rails, and another three to four weeks to erect the racks and integrate all the electrical components.
Popular Across The Pond
The technology has been widely used in Europe and Asia for decades—primarily because of the limited availability and high cost of land there. SSI Schaefer has installed about 1,700 mobile racking systems, most of them in Germany, Switzerland and Austria. The fastest growing markets are Asia, the Middle East and eastern Europe; an estimated 80 percent of all the cold stores in these regions are equipped with mobiles.
John Nofsinger, CEO of the Material Handling Industry of America (MHIA), though, expects the use of mobile racking to expand in the United States, due in large part to the European influence. "If you look at overall industry growth and the current levels of globalization and consolidation, you have a lot more companies here with ties to Europe and people there are comfortable using [mobile racking]," he says.
The potential, Nofsinger says, is probably greatest in storage areas where throughput is lower. "I can't see this in a high-volume operation because you would spend half the day just opening and closing aisles," he says. "It's probably best if you go with something like this for your lower-throughput SKUs. I'd still go with static racks for the higher-throughput SKUs."
Currently, only a few North American companies have these systems in place. SSI Schaefer has installed mobile racks at two North American companies, with plans for two other installations in the near future.