Industrial Docks

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JANUARY 2000 31

occurred to operators in the same propor-

tion. The study also found that off-dockincidents, which are more varied withrespect to direction of impact, tend toinjure one part of the body about thesame as the others. These incidents wereanalyzed to determine:

predominant type of off-the-dockincident;

relative frequency of off-the-dockincidents;

speed and direction of forklift travelprior to going off the dock;

Several major types of off-dock inci-dents were identified.

1) Slide off dock: This occurs whenthe dock surface is slick (with water, ice,oil or snow), causing the operator to losedirectional control of the lift truck. As aresult, the operator is unable to maneuveraway from the dock edge in time.

2) Dock edge: This occurs when theoperator has directional control of the lifttruck, but inadvertently drives off thedock edge while maneuvering close to it.

3) Trailer at dock: This involves for-ward trailer movement during loading(or unloading). It typically occurs whenthe trailer creeps forward, rolls away or ispulled away from the dock.

4) Miscellaneous: Incident types inthis general category include elevatorshaft incidents; falling from the secondfloor (or higher) of a building; or fallinginto water from a wharf or barge. Such in-cidents occurred much less frequentlythan the other types.

In this study, cushion-tire lift truckswere involved in four-fifths of all off-dockincidents; pneumatic-tire models account-ed for the remaining one-fifth. Cushion-tire trucks were involved in slide-off dockincidents, trailer incidents (most common)and miscellaneous events. Three-fourths of pneumatic-tire trucks were involved indock-edge incidents; the remaining inci-dents involved trailer-type incidents.

Based on these results, trends werenoted regarding what activity was beingperformed at the time of the incident.

1) Dock Edge Lift truck was traveling backwards in

more than one-half of the incidents.Predominant direction was straight

off the dock.Speed was generally slow.Lift truck was usually unloaded.2) TrailerLift truck was traveling in reverse in

more than one-half of the incidents.

Speed was slow.

Lift truck was usually unloaded.3) Slide off dockLift truck was moving forward more

often than in reverse.Lift truck slid off at an angle other

than perpendicular.Speed was at least moderate.Both loaded and unloaded lift trucks

were involved.

Narrow Aisle Lift Truck Study In a 19-year study (1975-1993) of nar-

row-aisle-truck-related injuries, 72 of the804 incidents were classified as off thedock. These were subdivided into threecategories, which identified the action of the narrow aisle (standup type) lift truckalong with a direction unknown catego-ry. Using these definitions, injury reportswere grouped into known or unknownaction of the truck and operator. (It should be noted that this study assessed data fromonly one lift truck manufacturer.)

Injury investigation reports from facil-ities that experienced the losses wereused to prepare data. In some cases, re-ports were incomplete. Table 2 identifiesdirection of travel as the lift truck went off the dock. Six operator actions were iden-tified as well (Table 3).

The study produced some interestingdata regarding the increased safety anoperator experiences by staying inside theconfines of the lift truck rather thanattempting to jump clear as the vehicle felloff the dock (Table 4). Fifteen operatorswho jumped from the falling vehicle didnot receive injuries. Three operators suf-fered major injuries and one died whenleaving the lift truck. Of the operators whostayed within the confines of the operatingcompartment, none received fatal injuries,while 10 received minor injuries.

Highlighting several of the more-seri-ous incidents helps to vividly describethe hazards of an off-the-dock incident.

Lift truck went off the dock when thedock plate fell. Operator was partiallyejected and suffered a crushed hand.

Worker drove lift truck rearward off of the dock. He attempted to jump clearand was pinned by the falling lift truck,causing major injuries to his torso.

Worker drove lift truck rearward off the dock. He either jumped or was eject-ed and was pinned by the overheadguard; as a result, his leg had to beamputed below the knee.

Worker drove rearward off of the

important statistics regarding dock-relat-

ed incidents.Dock injuries accounted for 29 per-cent of the injury total; approximatelyone-half of the injuries occurred while theworker was in a trailer.

Nearly 30 percent of all injuriesoccurred while unloading a vehicle.

More than 13 percent of those injuredwere operating powered equipment.

Nearly 65 percent of all injuredworkers were manually lifting, carryingor handling materials at the time of theirinjuries.

Overall, 38 percent of workers suf-fered overexertion injuries while lifting orhandling materials.

Sixty-five percent of those injuredwere not wearing personal protectiveequipment (PPE) at the time of the injury.

Some 48 percent never received safe-ty training for the assigned job.

Although this study is more than adecade old, the cited hazards persist atmany docks.

Ontario Incident Data From 1990 to 1995, 17 workers in

Ontario were killed by forklifts and 143were critically injured. Some of these inci-dents occurred at docks. The WorkersCompensation Board cited statisticswhich showed that most of the disablinginjuries occured when workers werestruck by forklifts. Specific dock-relatedincidents cited included lift truck tip-overs, workers being struck by fallingproduct and off-dock incidents withpowered equipment.

Between 1990 and 1995, approximate-ly 6,100 lost-time injuries occurred inOntario. Ministry of Labor inspectorsissued 327 orders related to the prov-inces OHS Act citing violations such aslack of operator training, improper proce-dures and failure to provide adequate lifttruck maintenance.

The Provincial Regulations for Indus-trial Establishments are very specific whenissuing citations. Of the 599 orders issuedduring this study, 63 percent involvedmechanical fitness of a facilitys lift truck aswell as at the dock.

Hyster Study: Off-The-Dock Injuries Hyster Corp. conducted an in-depth

study in 1985 to assess injuries related toforklifts and off-dock incidents. The injuries identified included head, leg, foot,ankle, arm and head injuries. All injuries


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dock and either wasejected or jumped.The forklift crushedhis heada fatalinjury.

The study report-ed some additionaldata that demon-

strates the need for better safety precau-tions. In addition to the 72 off-the-dockincidents, 127 lift trucks tipped over and 64pedestrians were struck by a lift truck orfalling product.

SAFE DOCK DESIGNEmployers can take steps to improve

the safety and efficiency of their docks.Dock design is the starting point. Forexample, a large area is needed in front of a dock so trailers have enough space tomaneuver into the docking zone. Sincemost over-the-road semitrailer trucks are65 feet long, this area must have at least asmuch space for backing in and pulling out.

Space for right-angle turns is anotherconsideration. The outside turn radiusmust be at least 55 feet, while the insideturn radius must be at least 25 feet. Thekey is to allow as much room as possibleto maneuver large trailers.

In April 1983, the U.S. government began to allow larger trailers on the high-ways. As a result, many trailers are now103 inches wide. Consequently, existingdock doors, seals and shelters must beenlarged to accommodate these trailers.For new docks, facility managementshould consult a dock equipment manu-

facturer to ensure that proper specifica-tions are adopted.

Ramp slope is another key considera-tion. A slight sloping driveway is best, asit allows for dock height to be about twoinches below the average height of atruck bed. Since a full trailer will be lowerwhen parked at the dock and higherwhen empty, dock height is crucial.Ideally, ramp slope should allow for athree-percent grade; three to six percent ispractical; 10 percent is near the limit,since a steep slope affects wheel traction.

Weather plays a role as well. Forexample, warehouse employees must getdown from the dock to the spotted trailerin order to check wheel chocks, trailercondition and landing wheels. To ensuresafe access from the dock, a ladder de-signed according to OSHA specificationsshould be provided. Stairs with handrailsand non-skid steps are also needed.Employees must also know that jumpingoff the dock is not acceptable, and signsshould be posted to reinforce this rule.

Typical Dock Hazards The unintentional movement of trailers

is one of the more dangerous actions thatoccurs at a dock. Because a lift truck caneasily fall from the dock due to trailercreep or premature departure, the trailermust be secured.

When one considers that a dock platehas a small moveable lip which is approx-imately 15 inches wide, it becomes clearthat placement and security of this platecan be the difference between life anddeath. The dock leveler lip extends fromthe dock plate onto the rear of trailer bed.This metal bridge absorbs the impact of theforklift crossing over it repeatedly whileloading/unloading the trailer.

To better understand the frequency of movement over the bridge plate, considerthis scenario. Suppose a single dock doorhandles the loading/unloading of 10trucks per day, each with an average of 20pallets. This would equate to 200 loads,

32 PROFESSIONAL SAFETY

EVENT/EXPOSURE 1992 1993 1994 1995Contact with objects/equipment 1,004 1,045 1,017 915Struck by object 557 556 590 546Caught in or compressed by object 316 309 280 256Caught in running equipment or machinery 159 151 147 131Caught in or crushed by collapsing material 110 138 132 99

TABLE 1Fatal Occupational Injury by Event or Exposure Warehousing

The unintentional movement of trailers is one of the more dangerous actions thatoccurs at a dock. Because a lift truck can easily fall from the dock due to trailer

creep or premature departure, the trailer must be secured. To address thisproblem, industry has developed several safeguards, including trailer restraints

(left), warning signs and lights (right) and dock levelers and barriers (below).

P H O T O S C O U R T E S Y R I T E - H

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multiplied by at least 250 workdays peryear = 50,000 total movements. This total isthen is doubled because of actual crossings(two per load). Thus, some 100,000 cross-ings could occur per year at each dockdoor. At a facility with 10 dock doors, near-ly 1 million crossings would occur.

In light of such activity, it is inevitablethat a trailer could be pulled away or grad-ually creep forward, exposing the forklift

operator to a potentially life-threateningfall. Each time a lift trucks wheels impactthe dock bridge, the trailer can inch for-ward. Even with its brakes set and wheelschocked, a trailer can move beyond thereach of the dock leveler bridge.

Wheel ChockingWheel chocks are a standard safety de-

vice. It is the forklift operators responsibil-ity to ensure that the wheels (on both sides)are chocked. However, wheel chocks areoften missing (stolen, lost) or go unused.Often, their use simply is not enforced.

In some cases, chocks are not fully effec-tive. For example, at an outdoor dock,snow or ice may cause chocks to slip awayfrom the wheel. Poor drainage can allowwater to pool in areas where trailer wheelsshould be spotted. Rather than wadethrough ankle-deep water to place andremove chocks, some employees may sim-ply decide not to use the devices.

Collapse of a landing wheel can causethe forklift and operator to be thrown for-ward into the nose of the trailer. Or, atrailer may tip to the side, causing the lifttruck inside it to be thrown against thewall of the trailer.

If a trailer is shorter-than-average, itslanding wheels are located closer to therear of the trailer; as a result, the trailer can be spotted outside of the building. Oncethe forklift has unloaded product from thetrailer, the weight of the lift truck andproduct will cause the back of the trailer toraise up and its nose to tip down and for-ward. This would propel the lift truck andoperator toward the trailers nose.

Trailer RestraintsAn automatic trailer restraint is

an excellent way to secure the trail-er to the dock. This device attachesto a trailers rear impact guard orInterstate Commerce Commission(ICC) bar. Approximately 90 to 95percent of all trailers can be securedusing such a device. However, trail-ers with hydraulic tail gates maynot have a rear impact guard; and,in some cases, the horizontal barmay be missing or damaged, pre-venting use of the restraint. Table 5reviews the pros and cons of usingsuch a device.

To activate the restraint, a workerpushes a button on a panel locatedinside the dock. This causes the hook

TABLE 3Operator Action Taken at Time of IncidentOPERATOR ACTION NUMBER PERCENT

Jumped 29 40Stayed 13 18 Jumped or ejected 10 14Partially ejected 4 6Attempted to jump 2 3No operator 2 3Unknown 12 17TOTALS 72 100

TABLE 4Operator Action Taken at Time of Off-the-Dock Incident

The industrial dockis a vital componentof the nations economy.Unfortunately, docks are alsothe source of many work-relatedinjuries.Dock workers canbe exposed to many hazards,particularly at docks thatare poorly designedor lack safeguards.

OPERATORACTION

NOINJURY MINOR MAJOR FATALITY UNKNOWN TO

Attemped jump 0 1 1 0 0 2 Jumped 15 10 3 1 0 29 Jumped orejected

0 0 5 4 1 10

No operator 2 0 0 0 0 2Partially ejected 0 0 4 0 0 4Stayed 2 8 1 0 2 13Unknown 5 3 4 0 0 12

TOTALS 24 22 18 5 3 72

TABLE 2Narrow-Aisle Truck Movement

INJURY/INCIDENT TYPE INJURY TOTALS PERCENTForward direction 13 18Rearward direction 32 44Dock plate fell 13 18Direction unknown 14 19TOTALS 72 100


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or bar to travel upward in order to lockagainst the rear impact guard. A flashinggreen light on the panel alerts the forkliftoperator that the hook has been placedproperly. A similar panel outside the dockdoor displays a flashing red light to warnthe tractor operator that s/he cannot pullthe trailer forward. A flashing amber lightsignals a system malfunction. If the rearimpact guard is missing or defective, aflashing red light inside the buildingreminds the forklift operator about thedanger of entering an unsecured trailer.

RECOMMENDED SAFEGUARDSReducing dock hazards requires in-

stallation of proper safeguards as well asincreased safety awareness. Systematicinspection and auditing also help.

The first step is to identify the sourceand types of injuries occurring in a facili-tys dock area. This can be achieved byevaluating past workers compensation(WC) losses. A firms WC carrier should be able to provide relevant cost and fre-quency data.

Beyond this, management must takesteps to organize product movement, con-trol traffic patterns and secure racking.Other issues include: facility lighting;extendable conveyors; PPE; chemical han-dling; employee training; fire safety; andequipment maintenance. The followingdiscussion highlights key considerations.

Good visibility is essential. Lightingmust be bright enough to ensure the safestorage of product and to help lift truckoperators recognize the presence of pedes-trians. Lights mounted on forklifts aidentry into trailers and facilitate operationson ramps or in remote areas.

Dock shelters at the bay doors should be in good working condition; this equip-ment must be properly maintained as well.

Heat strips/climate curtains can helpcontrol temperature throughout the building. However, pedestrians mustexercise caution when passing throughthese hanging plastic strips to avoid lifttruck traffic; where possible, a separatedoorway should be provided. In addi-tion, strips must be replaced as they become scratched and/or discolored.

To prevent falls, walkways, stairs,walking surfaces of ramps and dockplates should be coated with non-skidpaint. All walkways should be markedwith yellow lines to control traffic.

Spillsoil, fluid or greasewill affectthe stopping ability of powered equipmentand the walking surface for pedestrians.Leak sources must be corrected, and oiland grease spots cleaned up immediately.

Chemical spills can occur if a lift truckoperator drops or penetrates (with a fork)a chemical container. Dock workers must be aware of spill containment procedures;trained to recognize chemical hazards;

and know what PPE to wear when han-dling chemicals.

In addition, management must placespill cleanup kits in the dock area andtrain employees in their use. Dock work-ers must also understand the features of standard chemical container labels (e.g.,HMIS or NFPA 704); material safety datasheets must be readily available for anychemicals handled as well.

Fire extinguishers should be readilyaccessible, and employees trained in theiruse. Signs identifying fire safety equip-ment must be properly displayed. Lifttrucks that operate outside or in remoteareas must be equipped with a fire extin-guisher as well.

Sprinklers, extinguishers and otheremergency equipment must be protectedto prevent damage. A damaged sprinklerhead or broken pipe can cause significantwater damage to stored goods and willalso affect traction in the dock area (for both equipment and pedestrians). Pipes

can be identified by hanging caution signsor streamers on them for greater visibility.Barriers can be placed in strategic locationsto prevent damage by lift trucks/loads.

Loading/unloading flatbed trucksposes some unique risks. The typicaltrailer contains walls and a roof, whichprevents the lift truck operator from driv-ing off the side of the trailer. Mostflatbeds have no sidebars to prevent this.Therefore, if possible, flatbed trailersshould be loaded/unloaded from thedock well or other flat/lower surface.

Some docks are equipped with fixed orextendable conveyors, which can be usedto move product inside a trailer. Safe-guards that must be considered include:guarding of moving parts and nip points;power disconnects (if applicable); properlighting; and correct height adjustment forergonomic factors.

Basic PPEhard hats, gloves, steel toe boots and eye protectionis a must.Task-specific gear such as face shields,rubber gloves, earplugs/muffs, rubber boots and dust masks should be provid-ed as necessary.

Safety inspections are essential. De-pending on dock activity, product beinghandled and past safety performance,weekly inspections may be necessary. Tocreate the proper inspection form, a losscontrol professional should prepare acomprehensive list of safety factors pre-sent at the dock. Informal daily inspec-tions are also an important component;they can be facilitated by concise, easy-to-read checklists.

Operator training is critical. Each fork-lift operator must receive training specif-ic to the type of powered industrial truckthat will be used.

Due to the large amount of manualhandling performed at docks, backinjuries are common. Where possible,

34 PROFESSIONAL SAFETY

Securely holds trailer to dock.Employees can be easily trained.Can be used despite inclement weather.Saves time and money on the wheel chocking process.Restraints are simple to use.

Provides greater security than standard wheel chocks.Hook-type models help in preventing forward or side-tippingof trailers.

Restraints can prevent injuries and fatalities.Workers compensation costs would be reduced.They require only minor maintenance.Lawsuits would be reduced.Prevents forklift damage if a truck goes off the dock.Can help in the security of trailers in preventing trailer theft.

More expensive than wheel chocks; however, it is a small investmentconsidering the benefits.

Purchase and installation costs could be out of reach for some smallemployers.

Periodic maintenance and repair may be required.A restraint may not be effective on every trailer or truck.Flashing red light on the inside panel does not guarantee that an

operator will not drive a lift truck into an unsecured trailer.

TABLE 5Pros & Cons of Vehicle Restraints

PROS

CONS


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Industrial Docks

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