It's an age-old problem - effective storage and staging of all sizes and shapes of inventory. On one hand, you have to make best use of floor space and the cube of the building. On the other hand, you have to be able to reach specific items at a particular time to meet a production schedule or order shipment date.

Manual storage and staging equipment is the most frequently selected solution to this balancing act.

For small, individual items, your options include bins and drawers. Shelving and cabinets are often the answer for larger items that are much smaller than pallet loads. And for the largest units of inventory, there are several designs of unit load racks for heavy pallet loads of 2,000 pounds or more. Then there's the matter of long items such as tubes and rods. That's where cantilever racks come in.

The challenge is to pick the option best suited to your needs. There are nine typical variables:

• Item and load size
• Floor space and building height
• Desired storage density
• Installed cost
• Load accessibility
• Load rotation
• Required throughput
• Storage scheme (first-in, first-out and others)
• Length of time for storage and staging.

For the smallest items, bins and drawers are a common choice. Bins can be standalone units or stacked, holding a quantity of parts that are typically used individually even if in large quantities. Modular drawers are the next step up, offering the best high-density storage for small items. They can be portable and adjustable, and they contain several layers of drawers, each compartmentalized with partitions and dividers.

Shelving and cabinets are typically used for high-density storage of even larger quantities of small parts, as well as larger items or components and cartons. Shelving is usually open, while cabinets are shelving with a protective door in front of shelves with a solid back and sides. Both are adjustable to match their shape to the items and cases they hold. For instance, some types of shelves can rotate manually like your dining room lazy Susan. Meanwhile, shelving distance can be adjusted to accommodate a changing mix of inventory.

For all larger inventory units, there is rack. While usually 12 to 18 feet high, rack can rise to 40 feet or more, depending on ceiling height and storage density required.

The basic unit of rack is a bay. Loads are supported by two parallel horizontal steel supports bolted to four vertical supports, one at each end of the horizontal beam. The height of each bay is determined by the maximum height of the loads that will be stored in them. Several bays are bolted together in two parallel rows to create an aisle of rack. The distance between the rows of rack is wide enough for lift trucks to drive through for pickup and delivery of loads.

The most common type is single-deep pallet rack, where loads are stored one pallet deep. That allows maximum accessibility but the lowest storage density.

Double-deep pallet rack is twice as deep with pallets stored one behind another. That doubles storage density, but it compromises accessibility—the front bay must be empty before the rear can be reached. Unless you are using a last-in, first-out (LIFO) storage scheme, loads will have to be double-handled to access loads in back. You'll also need to use a reach truck rather than a standard counterbalanced lift truck to maneuver loads into the rear position.

If you can balance the demands of accessibility and storage density, drive-in rack is a possibility. It extends the storage concept so pallets can be stored three, four, or more loads deep. Workers retrieve the pallets by driving lift trucks right into each bay. But pallet access still depends on running a LIFO routine, and you may need to upgrade your reach truck to handle the higher levels. A similar option is drive-through rack, which allows lift trucks to enter from either end of the rack (not just the front).

If a first-in, first-out (FIFO) storage scheme works, gravity flow rack is a possibility. It offers the flexibility to store or stage items from carton to pallet size. The rack is loaded (or replenished) from the rear, with each load rolling along wheels or conveyors mounted in the rack. The load moves as far forward as possible, stopping when it hits either the front of the rack or the load in front of it.

A similar option for pallet loads only is push-back rack that stores loads two to five deep. The first load is placed on a cart by lift truck. The next load is maneuvered into position by pushing back the first until it too is on a cart. And since it's push-back, access is LIFO.

A more highly engineered version of gravity flow rack is high-density dynamic storage (HDDS). Powered by either gravity or mechanical means (such as pneumatics), this offers FIFO access by manipulating loads as they move.

If you're more concerned about storage density of pallets and cartons than flow, moveable rack is an option. Mounted on carriages, each rack unit can be rolled up against its neighbor, to minimize the total footprint. The downside is there's just one aisle, so access can be slower. And you need strong safety precautions to protect workers wandering the aisles.

The last type of manual rack is cantilever, for those loads that don't fit on pallets. Cantilever looks quite different from other types of rack. It consists of two uprights mounted on a base for vertical support. Spaced at regular distances on the vertical members are horizontal supports that are the arms of the rack. Tubes, rods and other long items are placed on the arms of rack.

Click on the icon to read more about large parts storage and staging.

Rack Manufacturers Inst. members, MHIA

Advance Storage Products, Div. of J.C.M. www.advancestorage.com
Andersen Rack Systems, Inc.,
  a subsidiary of Hannibal Industries, Inc. www.andersenrack.com
Base Manufacturing www.baserack.thomasregister.com
Engineered Products www.engprod.com
Frazier Industrial Company www.frazier.com
Global Storage Systems www.globalrack.com
Hannibal Material Handling, Inc. www.hannibalindustries.com
Inca Metal Products www.incametals.com
Interlake Material Handling, Inc. www.interlake.com
John W. Hancock, Jr., Inc. www.hancockjoist.com
Kinway (Auto-Lok, Inc.) www.king-way.com
Lodi Metal Tech, Inc. www.lodirack.com
Mecalux Corp. www.mecalux.com
Morgan Marshall Industries Inc. www.morganmarshall.net
Paltier, LLC, a Lyon Company www.paltier.com
Prest Rack, Inc. www.prestrack.com
Ridg-U-Rak, Inc. www.ridgurak.com
Space Rak, Div.of EWCO www.spacerak.net
Speedrack Products Group, Ltd. www.speedrack.net
Steel King Industries, Inc. www.steelking.com
Unarco Material Handling, Inc. www.unarcorack.com
United Fixtures Company,
  Monarch Div. www.monarchstoragesytems.com
United Steel Products Company,
  Division of U.S.E., Inc. www.usprack.com
W.C. Cardinal Co. www.wccardinal.com
Wireway Husky Corp. www.wirewayhusky.com