Narrow-aisle lift trucks can economically address space concerns. For example, if you renovate your racking from a counter-balanced system to one that accommodates a straddle or single-reach lift truck, storage can increase by 15 percent. Go to a double-reach narrow-aisle configuration, and you could realize up to 54 percent increase in storage space over the counter-balanced lift truck racking configuration!

"You'll see narrow-aisle configurations used heavily in grocery, light to medium manufacturing and other warehousing where space is a premium commodity," says Bruce Camenisch, product manager of Clark Narrow Aisle and Powrworker lift trucks. "The units offer greater storage density per square foot and higher lift heights at full capacity when compared with counterbalanced trucks."

Camenisch offers the following guidelines to consider when weighing the viability of a narrow-aisle configuration.

Narrow-aisle units defined: These Class II electrically-powered machines work in aisles 8 to 9 1/2 feet wide. Most configurations are stand-up riders, which increases productivity and operator comfort because their jobs typically require them to get on and off the machines often. Clark narrow-aisle units reach as high as 30 1/2 feet and are capable of taking full-capacity loads as much as 38 percent higher than a similar-sized counter-balanced lift truck. They can handle loads up to 4,500 pounds, and are available in straddle, reach and double-reach configurations.

Straddle unit configurations: Straddle units can be used in raised rack and straddle configurations. These units typically use uniform pallets with at least 6 inches between loads. On straddle configurations, a side-shifter can improve efficiency because operators don't need to position the lift truck exactly before picking up a load. Also, aisles can be narrower when compared with raised-rack configurations. When compared with reach trucks, the units are less costly to purchase and maintain because they do not have a pantograph.

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These units do a have a few disadvantages: There is no pallet flexibility, and more space is required between loads in the rack. Because the units must straddle pallets on the bottom rack, how pallets are positioned in the rack is key to productivity. A raised bottom beam can accommodate the straddle truck, but increases racking costs. Finally, resale value on straddle trucks is lower than reach trucks.

Reach truck configurations: Reach trucks feature a pantograph that allows the operator to extend or retract the load without moving the lift truck. With the pantograph retracted, the unit mimics a straddle truck, so throughput may equal a straddle truck while offering pallet and load size flexibility. Because it places the load in the rack after positioning, rack damage may be less likely. It also allows less space between loads, and has higher resale value than a straddle truck. The downside to single-reach trucks is they are more costly to buy and maintain and require slightly wider aisles than straddle trucks.

Double-reach configurations: Here, operators are able to extend the pantograph far enough to reach into the racks so that loads can be stored two-deep. Offering up to a third more storage than a single rack system, these are best used where many like products are stored. The double pantograph requires a wider aisle, but the double-reach configuration reduces the total number of aisles in a facility. Like the single-reach units, they are more costly to buy and maintain. Because it takes slightly longer to position items in the back of the rack, throughput may be slower.

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Penciling narrow-aisle configurations: The best place to start is get information from your local Clark dealer. In addition to the usual lift truck variables such as truck capacity, lift height and other factors, there are even more variables with narrow-aisle configurations. Things to consider include reach vs. straddle, battery compartment size and outrigger dimensions. They all impact storage configuration. Your Clark dealer has extensive experience in narrow-aisle configurations, and can help you get the very most from your precious warehouse space.