Warehouses and distribution centers are under continual pressure to handle more of everything: more inventory, more stock-keeping units (SKUs), more orders, more shipments. But adding on to existing buildings to accommodate growing demand isn’t always feasible or cost-effective. Instead, many facilities choose to increase storage density within their existing footprint by narrowing the aisles and adding higher racking—and new high-volume DCs often are laid out that way from the start. In either case, specialized lift trucks are required to navigate the narrow aisles and access high-bay storage. Among them are “man-up” forklifts that elevate the operator to perform picking and putaway tasks at heights ranging from four feet to well over 50 feet, depending on the trucks’ manufacturer and model.
Working high above a cement floor is not for everyone, though, and it’s reasonable to wonder how safe that may be. Rest assured that man-up forklifts are engineered to be sturdy and to comply with strict safety standards. There also are some must-know rules and best practices for safe operation that are unique to these non-traditional trucks.
THE BASICS
Man-up trucks for warehouse applications are designed to operate in narrow and very narrow aisle (VNA) environments—narrow aisles generally are defined as 8.5 to 10.5 feet wide, while very narrow aisles usually are five to seven feet wide. The main categories of man-up trucks include order pickers, also called order selectors or stockpickers, and turret trucks, sometimes known as swing-reach trucks.
As their name suggests, order pickers are mostly used for case picking, with operators selecting products and placing them onto a pallet staged at the same height as the operator’s platform. Turret trucks feature a rotating head or a sliding mechanism that allows the forks to swivel to either side of a very narrow aisle. They are most often used for picking and putaway of full pallets but can also be used for picking cases onto a pallet.
Some OEMs also offer specialty equipment. One example is furniture order pickers, which have extra-long platforms and an attached cart for handling oversized items. These types of trucks are offered by Toyota Material Handling, Crown Equipment, and others.
How high man-up trucks can lift varies with the equipment type, the manufacturer, and the model’s load capacity. Maximum fork heights for standard order pickers offered by the OEMs we spoke with for this article range from 30.5 feet to 41 feet, while the maximum fork height for low-level order pickers that work the first and second tiers of racks is four feet. (Crown Equipment’s Wave low-level order picker, which is designed for stockrooms and similar environments, can go higher; its platform lift height of up to 118 inches allows the operator to reach up to 17 feet.) The majority of order pickers in North America have maximum heights of 366 inches (30.5 feet) or less, according to Jim Hess, director of business development for warehouse products at Yale Lift Truck Technologies. However, the effective pick height is higher when you add six inches or so for the platform height and 60 inches for the operator’s height, he notes.
Turret trucks are designed to reach much higher. Maximum fork heights for models offered by the manufacturers we spoke with range from 50 to about 59 feet. There is demand for even higher lifts, especially in Europe; Germany-based Linde, for example, says it will introduce a 62-foot turret truck next year.
Because they are lifting both loads and people, these forklifts must be extremely stable. Turret trucks, for example, require exceptionally heavy bodies and batteries that together can add up to 22,000 pounds or more, says Yanis Harmance, senior product manager for Class 2 and 3 products at Linde, which is part of Kion North America. Ballast can be added if needed to enhance stability, and the trucks’ mast—which includes a main mast and an auxiliary, or “mini,” mast that can be used in high racking when ceiling heights limit the extension of the main mast—is engineered for extra strength and stability, he explains.
VNA equipment may use a guidance system that locks the trucks into a straight path in the center of an aisle. (In many operations, order pickers are allowed to move freely in narrow aisles under certain conditions.) One popular choice is a wire guidance system that relies on energized wires embedded in the warehouse floor—wires that “nowadays use sensors to communicate with the truck,” says Tim McMahon, manager, advanced technology at Abel Womack, a Raymond Solutions and Support Center. Another common method is rail guidance. This system uses metal guide rails installed on top of the floor on both sides of the aisles, between the racks and the forklift path. Side-mounted rollers on the truck contact the rails; together with sensors, they keep the forklift on the correct path.
Wire systems typically are less costly to install and maintain—a major consideration in very large DCs that may require as much as 100,000 linear feet of wire, Hess says. The cost of hardware, installation, and maintenance make mechanical rails more expensive, but rails may make sense in facilities with fewer, comparatively shorter aisles, he adds.
THE OPERATOR EXPERIENCE
With order pickers, operators stand on a platform that raises and lowers with the mast. The platforms have an overhead guard, and most are open on three sides with protective side rails. (Some OEMs also offer full enclosure as an option.) Operators are required to wear a specified type of safety harness with a self-retracting lanyard. The lanyard usually is tethered to an overhead bar and can slide across it so the operator can work each side of the platform, explains Michael Stridick, warehouse solutions manager at equipment manufacturer Hyster.
Turret trucks place the operator on an ergonomic seat in a partially to fully enclosed compartment that rises with the mast. Most of the models in North America are open on one or more sides, and the Occupational Safety and Health Administration (OSHA) requires their operators to wear a tethered harness. According to the experts we consulted, operators of turret trucks with full-perimeter guarding do not require a tethered harness unless the operator raises the side gates (thereby eliminating the full enclosure) while the platform is elevated. Several OEMs offer full enclosure on certain models or as an option, but for Jungheinrich and Linde—whose trucks are designed in Europe—full enclosure is the standard design. In all cases, says Joe Bach, product manager at Crown Equipment, operators must wear a harness with a self-retracting lanyard when required by OSHA regulations and American National Standards Institute (ANSI) standards.
Both order pickers and turret trucks require special operator training. That’s because “OSHA requires forklift operators to be trained and certified for the specific equipment they will work on for the specific facility where they will use it,” McMahon says. This means that, in addition to the standard instruction required for operators of all lift trucks, “operators of man-up equipment must learn how to safely work on the platform, use the tethered harness, and elevate and lower the platform,” he explains.
Some people, though, cannot tolerate heights or vertical motion, and employers should always take this into consideration before qualifying them to operate man-up trucks, says Michael Brunnet, senior manager, warehouse and systems truck sales for Logisnext Americas, which represents Jungheinrich and several other lift truck brands. Discomfort with heights can also compromise productivity, for example, by leading operators to drive at ground level to a rack position, raise the platform to pick an item, come back down, and then move to the next position instead of traveling while elevated. “That’s feasible, but it’s inefficient and is not how the equipment is designed to operate,” Brunnet says.
Virtual reality (VR) simulators can add value as a supplement to—but never a replacement for—OSHA-mandated hands-on training on the truck operators will actually use. “A virtual reality simulator can help trainers get a sense of how someone might react to heights, with no physical risk to the trainee or the facility,” McMahon observes. It’s helpful, though, to be aware of how VR compares to operating an actual lift truck. “I’ve done both,” says Brad Shofner, product planning manager at Toyota Material Handling, “and while VR certainly has its benefits, it’s hard to truly replicate the feeling of being elevated or operating in reality.”
Bach and other experts suggest assigning the most experienced operators to order pickers and turret trucks. “Customers generally don’t have brand-new operators working at height,” he says.
TECHNOLOGY ENHANCES SAFETY
Forklift manufacturers have invested heavily in safety-enhancing technologies for man-up trucks. One widely available innovation limits lift heights to avoid overhead obstructions, such as sloped or lower ceilings, sprinklers, signs, lights, and ventilation equipment. A representative example is Hyster’s approach, which begins with reviewing detailed facility plans, followed by a site visit. Once the requirements have been mapped and confirmed, RFID (radio-frequency identification) transponders are installed in the floor on each side of an aisle. As a truck approaches, sensors scan the tags to identify the location, and a programmer tells the truck what the “rules” are for that particular aisle, Stridick explains. He gives the example of an aisle with an evaporator that hangs over 12 sections of rack and is lower than the surrounding ceiling. The system can be programmed to stop the truck so the operator can lower the mast before it passes under the evaporator. Then once the truck has moved a predetermined distance past the obstruction, the system allows the operator to raise the mast to its previous height.
Different manufacturers offer additional, more fine-grained capabilities. For example, Linde’s optional Aisle Safety Assistance system not only is able to limit the lift height in specified areas but can also limit the height of specific parts of the mast (main or auxiliary) and prevent a turret truck’s carriage from swiveling in specified areas. Another example is an optional feature from truck-maker The Raymond Corp. that allows operators to override pre-set limits—which are programmed by a Raymond-certified technician or at the factory—when necessary.
Brunnet notes that technology allows operators to improve efficiency by doing something they’ve been trained not to do for sit-down, counterbalanced trucks: raise and lower the mast while in transit to picking or putaway locations within an aisle. (This is not recommended when changing aisles or in areas without aisles.) An efficient trajectory for the elevated operator saves time and reduces battery draw by following a curved, or “diagonal,” path that minimizes how much the mast and platform are raised and lowered while performing tasks. For safety, manufacturers have developed technology that limits the platform height, lift/lower speed, and travel speed while the truck is in motion. “The faster and higher you’re lifting, the more the travel speed is restricted,” he explains.
The specific capabilities of these controls vary with the manufacturer. Toyota, for example, offers an option called Lift Logic that continuously monitors and adjusts travel speed and lift heights for maximum efficiency and safety. Without Lift Logic, Shofner explains, the truck will still manage the height and speed, but it will not be constantly adjusting and will be limited to pre-set constraints.
An interesting safety technology developed by Linde and its sister company Still is a rescue alarm for elevated operators. If the operator does not perform any tasks or move the truck within a specified time frame, an alarm will sound. As more time passes with no activity, the alarm grows louder and a light begins to flash, alerting nearby workers, who can lower the mast and operator compartment to floor level if necessary. Harmance says it’s a rarely needed but welcome capability if an operator should faint or have a medical emergency while elevated.
Technology can also reinforce operators’ safety training on important practices like always attaching their harness and tethered lanyard before operating a man-up truck. Raymond, for example, offers an optional electronic harness connection through its iWarehouse telematics system. If the system does not detect a proper connection between a self-retracting lanyard and an operator’s harness, the operator receives both audible and visual notifications, travel speed is limited to one mile per hour, and lift capabilities are disabled until a proper connection between the harness and the lanyard is detected. With certain configurations, the system can report on operators’ behavior, so a supervisor can proactively monitor operators and take corrective action when needed.
MORE SAFETY TIPS
While technology and built-in safety features are extremely important, experts recommend additional steps to help keep operators safe while they’re working at height. One of the most important, says Bach of Crown Equipment, is ensuring that the floor where man-up trucks will be working is level and smooth. “You need a flat, level surface, so when you travel and lift, there will be less lean induced into the truck,” he explains. “If the floor has a certain degree of forward-and-back or side-to-side inclination, it gets amplified as the platform goes higher,” which can make operators feel uncomfortable and lose confidence.
Operators should always be aware not only of their surroundings at height, but also of what’s happening at ground level ahead of and behind them, Brunnet adds. Even when warehouse rules allow only one truck per aisle and no pedestrians at all, it’s best to verify that the aisle is clear before moving from a position, he says. And although object- and pedestrian-detection technology and back-up cameras are helpful for improving awareness, a careful, 360-degree visual check is required by OSHA and the manufacturer.
Toyota’s Shofner stresses the importance of choosing safety-harness lanyards of the appropriate length for the application. A lanyard that is too long, for example, could allow an operator to step onto racking to get extra leverage or reach—something that is never advisable, he says. A manual extension tool that lets operators pull a case closer can help increase an operator’s reach and minimize leaning.
Stridick of Hyster and Hess of Yale emphasize the importance of properly matching the size of the operator’s platform to the width of the aisles where a truck will work. For example, trucks that follow a wire in the middle of a 72-inch aisle should have a 60-inch wide platform, leaving a maximum of six inches on each side. A larger gap will position operators too far from the racks and may encourage them to step on racks or reach too far over the side of the platform, both of which are dangerous, they caution. Efficiency is also at risk when operators take chances. As Stridick puts it: “Safety and operator productivity go hand in hand.”
Lift trucks that elevate operators are a special breed, with unique design characteristics, capabilities, and requirements for safe operation. But core safety principles apply to these forklifts, just as they do to any other. Regardless of which kind of lift truck is involved, “safety protections start with people,” McMahon says. “At the end of the day, it’s up to people to make sure they are following procedures and that operators are properly trained.”
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