Lift truck tip-overs - A good story to tell, if you survive
- The Skinny on Narrow Aisle Configurations
- On the Dock: Avoid Lift Truck Accidents
- Are You Losing Money on Your Lift Trucks?
- Will-Fit Parts: There Are No Guarantees
- Avoid Lift Truck Run-Ins
- When is it Time to Trade?
- Lift Truck Tipovers: A Good Story to Tell, If You Survive
- Pay a Little Attention Now...Or Pay a Lot Later
Editor's note: Writer Dan Anderson works as a mechanic for an implement dealership; this is a true story.
Nobody got hurt, nobody got fired, and it eventually provided lots of laughs in the breakroom of the warehouse where I worked. But it shouldn't have happened. Steve and Tim, two 19-year-olds, were> changing light bulbs in an empty grain storage warehouse, using a sit-down forklift to lift Tim within reach of the light fixtures. If you were ever young and easily bored, you can probably guess what happened.
Steve, the driver, got tired of hoisting Tim up and down for each light fixture, so he began moving between fixtures with the mast extended. Things went well until they replaced the last light bulb, and Steve decided to give his buddy a thrill by making the run back to the other end of the warehouse at full speed, with the mast extended.
He forgot that bar trusses spanned the warehouse every 50 feet, at least until Tim's screams drew his attention to one of the fast-approaching obstacles. Steve slammed on the brakes. He swerved and the off-balance forklift skidded sideways and tipped over. The crash and subsequent yelling and screaming brought the rest of us on the run.
We found Steve still braced inside the forklift, shaken, while Tim dangled from the truss 20 feet overhead. At the last second, Tim had grabbed the lower bar of the truss and somehow managed to wrap his arms and legs around it. He hung wide-eyed from the top of the warehouse, hollering for somebody, anybody, to get him down.
It took a long ladder to get Tim out of the rafters, and a heavy front-end loader to set the forklift upright. The two young men had to pay the cost of repairing the forklift and after the bruises subsided, Steve was back to normal although a lot more careful. Considering what could have happened, it all turned out okay.[Back to the top]
Common sense and training rule
The moral of the story is that these two young workers didn't know that using a lift truck as a scaffold is downright dangerous, and that horseplay with a lift truck is downright stupid. Lift truck accidents are not uncommon, especially in small warehouses and facilities where untrained workers have access and reason to occasionally drive forklifts.
The Bureau of Labor Statistics confirms this claim. It cites the Census of Fatal Occupational Injuries article written by Gary A. Heimer, Fatalities involving forklifts and other powered industrial carriers, 1991-1992 that of 170 fatal powered lift truck accidents, 24 percent (41 of the total) of the deaths were caused by forklift overturns. The report shows that deaths from overturns were more frequent than the forklift striking something or running off the dock; worker pinned between objects, worker struck by material or forklift; worker falling from forklift or worker dying during forklift repair.[Back to the top]
Lift truck tip-overs are avoidable
Understanding the concept of a lift truck's "Stability Pyramid" is the key to keeping a truck upright and operating safely. As long as the machine's center of gravity is kept inside its imaginary Stability Pyramid, there is reduced risk of tip-over. You can find the Stability Pyramid for any lift truck by drawing an imaginary line from front wheel to front wheel, then back to the pivot point for the rear steer axle. The resulting triangle is the base of the machine's Stability Pyramid.[Back to the top]
At first glance it would seem that a four-wheeled lift truck would have a rectangular base instead of a triangle, but that is not the case. The steer axle pivots on its center pin, and that pivot pin becomes the third point forming the triangular base of each machine's Stability Pyramid. The top point, or peak, of a lift truck's Stability Pyramid is located near the back of the machine's mast, somewhere just above the operator's head. Its height depends on the height of the load, and its fore and aft location is determined by the tilt of the mast.
The Stability Pyramid grows taller or shrinks, skews or becomes more vertical as the operator raises and lowers loads and tilts the machine's mast. When a lift truck's forks are kept low, its Stability Pyramid is short and squat, making it relatively stable. Raising the forks elongates a truck's Stability Pyramid, making it tall, skinny, and much easier to tip over.
The center of gravity rises as the load rises, and now needs only to shift a short distance to get outside the narrow top of the imaginary pyramid and cause a tip-over, especially if the machine is moving. Momentum multiplies the torque caused by turning or operating on sloping or rough surfaces, dramatically increasing the potential for tip-overs.
Lift truck operators who understand the principles and limits of their truck's Stability Pyramid understand that keeping loads low, close to load backrests, and the mast vertical or tilted back slightly cuts tip-over chances. Carrying a load at the tips of forks, with the mast tilted far forward, or carrying high loads on a tilted mast may move the center of gravity near or into the danger zone. Well-trained drivers always wear a seat belt and keep the operator's platform clean.
Despite break room tales of drivers who brag of having leaped to safety when their sit-down lift truck rolled off a loading dock, the best place for a driver during a tip-over is strapped securely in the seat.[Back to the top]
Failure to use restraint systems can result in death or serious injuries. Tests with crash dummies and real-life accident reports show that in a tip-over, the driver usually falls or jumps out of the seat before the machine hits the ground, putting him at risk of getting crushed by either the machine or the overhead guard.
The overhead guard is what seems to get people who try to jump clear of a machine when it tips over. The guard extends enough that it's hard to jump far enough to get clear of it before it hits the ground.
Safety films of staged forklift tip-overs, using live volunteers, (who wore crash helmets and protective padding) show the volunteers getting a rough, but survivable ride when strapped into safety seats with seat belts. Unbelted crash test dummies in staged tip-overs invariably ended up under the forklift or pinned beneath the forklift's overhead guard.
The only exception to the rule of "stay with the machine" is for those who operate stand-up rider forklifts. Stand-up rider operators usually have opportunity to step off and away from the machine in a tip-over or off-the-dock accident, and CLARK recommends abandoning the machine when this type of accident is unavoidable.
A tidy forklift is a safe forklift
Keeping operators' platforms clean can also reduce injuries in case of a tip-over. Some drivers carry Thermos jugs, wrenches, chains, and other job accessories on their machines. While there have been no reports of deaths due to getting bonked in the head by a flying Thermos full of coffee during a roll-over, it can be an unnecessary headache that could have been prevented by keeping the operator's platform clear of loose items. Also keep the platform clear of materials to prevent objects from getting caught underneath foot controls such as brake pedals.[Back to the top]
Safety surveys show that the single most important factor in minimizing lift truck tip-overs is operator training. All the restraint systems in the world are worthless if a lift truck operator is not trained in the safe operation of a machine and encouraged to follow safe operating procedures. Unfortunately, few companies aggressively train their lift truck operators.
It is estimated that between 65 and 70 percent of lift truck operators have inadequate training. Companies have the perception that driving a forklift is a "low skill" job, and that's far from the truth. Driving a forklift efficiently and safely around all the obstacles in factories and warehouses requires skill and expertise. Compound this with dodging pedestrians and other forklift traffic, and a forklift operator has a very difficult job.
OSHA regulations currently require only that all workers be trained in the safe operation of any lift truck they operate in the course of their job. New regulations will be implemented, specifying exactly what sort, and how much, training is mandatory to operate each type of lift truck.
More intensive training required soon
The days of watching a 20-minute video and being 'certified' to drive a forklift are coming to an end. A good training program requires a minimum of four hours of classroom training and at least an hour or more of supervised driving. That's the direction the OSHA regulations seem to be headed in.
All lift truck drivers should be trained in safe operations, especially young drivers. Youthful exuberance and lack of practical experience can be a deadly combination. Superior Safety Training reports that workers under the age of 25 account for approximately 12 percent of all work fatalities but nearly 20 percent of all forklift-related fatalities.[Back to the top]
'Occasional' lift truck operators should not be overlooked when training personnel. Many small manufacturers and warehouses do not have full-time lift truck drivers, and those who operate the trucks are often more interested in accomplishing their tasks (such as changing light bulbs) than operating equipment safely. Because they are relatively unfamiliar with controls and lift capacity, the potential for accidents increases.
Many companies are reluctant to spend time and money on training programs for their lift truck drivers. That may change with the new OSHA regulations. In the end, the new training regulations will actually save money for companies, because well-trained drivers will cost less in accidents, repairs and downtime.