Preventing dangers at docks

Loading docks - instead of being hazardous places to work - can be equipped for far greater employee safety, higher productivity.

By Tom Feare, Editor At Large -- Modern Materials Handling, 8/1/2002

At worst, a loading dock is a danger zone. At best, it's a safe and productive place to work. And without the right equipment and practices, the difference between the former and the latter can be less than you might think.

Just consider this. A forklift operator loads 20 pallets per trailer, making 40 crossings of the dock per trailer loaded. The operator loads 10 trailers a day, and works 250 days a year. That's 100,000 crossings over this dock 'danger' area a year. Then factor in other workers, other dock positions, and multiple shifts. That's when you see that the opportunities for dock accidents are anything but remote.

Not only that, but they can be quite costly too. Just one forklift accident while traveling between a dock and a semi-trailer 'can easily add up to a dollar amount in seven figures in a heartbeat,' says Mike Pilgrim, executive vice president, sales and marketing, Poweramp, (www.poweramp.com, 262-255-1510). Medical bills, compensation to an injured worker, lost production, equipment and product damage, an increased insurance premium, and indirect costs can soon reach $1 million.

Now how do you foster a less accident-prone work area - specially when a dock is such a busy place? And how do you increase efficiency in dock operations?

First, identify the potential hazards. For instance, a trailer can pull away suddenly and prematurely, sending a forklift and its operator crashing down to the pavement. Or an operator can drive a forklift off a vacant dock position. Or a worker can slip and fall on unprotected dock surfaces wet from rain or snow. And the list continues from there.

Equipment is clearly part of the answer too. Fortunately, there are plenty of options to choose from; dock levelers, trailer and vehicle restraints, master panels for dock control/communication, seals, shelters and breakaway dock doors. They are among the equipment solutions that, individually and collectively, can make receiving and shipping far safer, despite high traffic conditions.

Very briefly, here's what each dock system component does. A leveler bridges the gap between truck and dock. (A large scissor lift does so too in light duty usage and portable applications.) A restraint secures a vehicle at a dock. A master panel energizes dock systems (such as a leveler and a restraint), controls the sequence of operations, and signals 'go' or 'stop' conditions.

Seals and shelters provide protection from weather and slippery docks. Breakaway doors do just that when hit with forklifts - but then can be put back into service quickly. (For more information see 'Click on MMH' icon.)

These dock solutions deliver higher productivity as well. And they can help limit damage to product and facility too.

A more complex world

Suppose that preventing trailer pull away is your chief safety concern. It's not enough to just say, 'put in a restraint,' and buy any piece of equipment. You have to match the type of restraint to the kinds of vehicles serviced. Similarly, dock levelers need to be sized for what they work with. The same holds true for seals and shelters. In any case, finding the right equipment solution for specific dock circumstances is more complex now than it was years ago.

Let's go further into restraint selection to illustrate today's complexity. There's greater variety in truck types and sizes now. A vehicle restraint designed to work with the rear impact guard (ICC bar) on a semi-trailer may be ineffective on an express delivery van fitted with a liftgate.

As a result, facilities that service some liftgate vehicles may have one or two dock positions with restraints designed specifically for them, says Steve Sprunger, director of sales, Serco (www.sercocompany.com, 972-466-0707).

Dock equipment, Sprunger adds, 'absolutely has become more application-specific today than it was years ago.'

Docks, moreover, need to be viewed as a material transfer zone and a vital link in the supply chain, says Walt Swietlik, customer relations manager, Rite-Hite (www.ritehite.com, 800-456-0600). 'Cookie cutter specs no longer suffice when designing docks for optimum material flow and true supply chain efficiency,' he maintains. A common mistake made today is to overlook the many factors that need to be considered.

Dock levelers are central to smoothing the flow across this material transfer zone. But, like restraints, they too need to fit specific conditions. For instance, many levelers need to be wider and longer than in the past.

To begin, many trailers are wider than in the past. Full access to a wider trailer's contents by a forklift may require the dock leveler to be wider, too, than the old standard of 6 feet.

This is because wider trailers may carry full-width racks, for example. Or contain double-wide pallets. Or single pallet loads may be 'pinwheeled' in a wider trailer, Swietlik says. When pinwheeled, one row or even two rows of pallets face out with the 48 inch-wide side of the pallet, instead of the 40-inch side, which makes forklift access far more difficult. All require full access to the trailer. And that doesn't even take into account the increasing pressure at consumer goods companies and elsewhere to maximize cube utilization of trailers.

Similarly, servicing trailers with low truck beds to achieve greater cube volume - those with beds 6 to 12 inches below dock - may call for a leveler longer than 6 or 8 feet. Otherwise, the slope down into the trailer may be too great for the forklift to negotiate easily.

For very low bed trailers, such as 'super vans,' even a 12-foot-long leveler may be inadequate, says Swietlik. In these cases a truck leveler may be required.

End users also have to choose among non-powered, or mechanical levelers, and powered models, where a hydraulic system, an air bag, or an electric motor raises and lowers the leveler deck.

Some customers, Swietlik says, now want to segregate their receiving and shipping areas, for example, instead of having a common receiving/shipping area. Receiving may be oriented to full pallet loads, while shipping sends out small packages. One specification for the entire building doesn't apply. 'We have to look at both sides of the facility,' he says.

Some customers also want point-of-use docks instead of distinct receiving or shipping docks. Raw materials go directly to where needed and finished goods ship right from where they're made. The net effect, moreover, is to cut down on forklift traffic within the facility.

Specifying dock systems becomes even more difficult when the facility is a third-party logistics provider, observes Eric Breen, director of sales, Kelley (www.kelleycompany.com, 800-558-6960). Unlike a private firm with a fixed business, a 3PL's 'current customer may be gone in five years,' he says. So a 3PL needs to design its dock systems so they 'will cover the most customers over the life of the equipment,' he adds.

Most dock levelers come with 10-year warranties; many might last twice as long. Dock leveler capacities, for example, need to be specified for a 3PL to fit both today's client and a potential, future customer. The future customer might be moving heavy rolls of paper over the levelers compared to the lighter loads of today's snack food warehouse, Breen says. 3PLs 'need to build their docks for the worst case situation.'

Dealing with trailer creep

Whether a 3PL or not, another common cause of accidents is trailer separation from the dock. Dealing with this safety issue, however, is not just a matter of preventing the semi-trailer driver from leaving before loading/unloading is finished. Both trailer creep and dock walk are common concerns, and trailer/vehicle restraints a good solution.

A trailer at a dock creeps - that is, it moves slowly and horizontally away from the dock face - as forklifts with loads move in or out of the trailer. 'Trailer creep has always been a safety issue,' says Sprunger. Trailer creep can eventually lead to failure of the trailer's landing gear, moreover.

More recently, 'dock walk' has become a concern, however. Dock walk results when forklifts move in and out of trailers equipped with air ride suspensions. Some two-thirds of new trailers have them. And about half of all trailers now on the road are air ride trucks, says Swietlik.

Unless air is bled from the trailers' suspension systems, the trailers bounce up and down - as much as 8 inches - and they can eventually walk away from the dock. Low-profile (smaller diameter) tires on air ride trailers can compound the problem.

Trailer manufacturers have developed and tried out dock walk prevention devices, but 'it's a difficult challenge as most devices add weight and cost to the trailer,' says Breen. 'It's a huge problem.' What's the first precaution to take? 'You have to bleed the air,' he says.

More importantly, installing trailer/vehicle restraints can help prevent both trailer creep and dock walk problems. They also aid in restraining the truck whose driver either tries to make a premature departure or attempts to aggressively pull away from the dock. And they can help avert a trailer landing gear failure or tipover.

Restraints are of two basic types: Some restraints grip or hold the trailer's rear impact guard (ICC bar). Other restraint systems engage or hold the vehicle's rear wheels.

Restraint selection 'is very end-user driven,' says Pilgrim. The range of vehicle types serviced makes for application specific equipment selection. Also, some users may want automatic latching, for example. Some users may permit drivers to activate restraints, some may not, points out Pilgrim.

A master panel provides a means to energize a leveler and a restraint and, more importantly, to centralize and control dock operation to prevent a dock worker from making a mistake, explains Sprunger. 'There's a logical sequence to follow,' adds Swietlik.

Click on this icon to read the case study on the application of dock equipment at Rite-Hite.

Click on this icon to read the case study on the application of dock equipment at Serco.

Click on this icon to read the case study on the application of dock equipment at TKO Door.

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