The Basic Principles of Forklift Stability and Safety

How to prevent tip-overs and protect pedestrians.

By: Russell Niedzwiecki, Contributor

Forklifts tend to be narrow (as measured by the track which is the distance between tires on the same axle). The interrelationship of a truck’s track, wheelbase (distance between axles), height, load weight and height, and counterbalance weight will influence its stability.

Too much weight or force in front will cause a front tip-over. If the load’s center of gravity shifts due to a turn or a change in fork height, the truck may tip over to the side.

HOW A FORKLIFT IS LIKE A SEESAW

Most of us understand how a seesaw or teeter-totter works. The ends of the board move up and down based on the weight and force placed on either end.

A forklift is kind of like this piece of playground equipment. The weight of the load competes with the weight of the counterbalance (engine plus added weight). Just as the seesaw has a pivot point on which it rests, the front wheels are the balance point for a forklift. Too much weight on the forks will cause the truck to tip forward.

THE STABILITY TRIANGLE

Picture the forklift’s front and rear axles. If you connect the front tires with a line and then draw a line from each front tire to the rear axle pivot point, you’ll create the stability triangle. For accident-free operation of the forklift, the forklift’s center of gravity and the load’s center of gravity need to line up in the stability triangle.

MAINTAINING STABILITY AND PREVENTING TIP-OVERS

The key to preventing tip-over accidents is understanding the variables that affect stability.

• Weight – of the load and the counterbalance
• Center of gravity – of the load and the forklift itself
• Height of the load – affects center of gravity
• Speed of travel – affects center of gravity
• Cornering – shifts center of gravity

Carefully loading a truck, carrying loads with the forks low and tilted back, raising and lowering loads carefully, and maintaining a reasonable speed will greatly reduce the risk of tip-over accidents.

FORKLIFT SAFETY FOR PEDESTRIANS

How can we protect pedestrians in the workplace from forklift accidents and injuries? Pedestrians need training too!
In even a low-speed collision, the human body is no match for a forklift. Weighing in at an average of 9,000 pounds, without a load, a forklift is three times heavier than a car and much less maneuverable.

You know the dangers forklifts pose for operators. That’s why you invest in training. But were you aware of the danger they pose to pedestrians?

These vehicles operate throughout facilities where workers are going about their business, but, at times, workers forget there’s heavy equipment moving around near them. That leads to pedestrians being injured and even killed in forklift-related accidents. Injuries and fatalities occur when forklifts strike pedestrians or when pedestrians are struck by falling loads. According to a 2024 OSHA report, roughly 36% of forklift-related deaths involve pedestrians.¹

No plant manager wants anyone injured or worse. Besides the human toll, these accidents can lead to expensive and disruptive lawsuits, compensation claims, and more. While OSHA is clear about its requirements for operator training, it’s silent on the issue of training pedestrians. Here are suggestions for managing these hazards:

Carrying loads with the forks low and tilted back, raising and lowering loads carefully, and maintaining a reasonable speed will greatly reduce the risk of tip-over accidents. © Acik – stock.adobe.com

FORKLIFT OPERATOR SAFETY TRAINING

Forklift operators must be aware of workplace conditions, including pedestrian traffic.

When a person or group walks across the route, the operator should:

• Stop
  • Wait until they pass by.
  • Proceed cautiously through congested areas.
• Think ahead. If an area is cluttered, the operator should walk the route first to spot problems. Also, he or she should:
  • Use a spotter when needed.
  • Sound the horn or other alarm at blind corners, doorways and aisles and when backing up.

PEDESTRIAN SAFETY TRAINING

Here are some reminders that can keep pedestrians safe:

• Forklifts can’t stop quickly. They are designed to minimize load damage and maintain stability, so they stop slowly.
• Forklifts are heavy. Stand clear when they’re in operation.
• The driver may not be able to see you.
• Forklifts have a wide rear swing radius. Stay out of the way.
• Use pedestrian walkways or stay to one side of the equipment aisle.
• Never ride on a forklift, unless authorized and the forklift is designed for riders.
• Don’t pass under an elevated load.

IDEAS FOR PLANT SAFETY MANAGERS

Per OSHA’s standard for the use of mechanical equipment, 29 CFR 1910.176(a), aisles and passageways must be free of obstructions and marked where mechanical equipment is used.² The following can help compliance and make your facility safer:

• Consider separating pedestrians from lift trucks by providing:
  • Walkways
  • Permanent railings or other protective barriers
  • Adequate walking space on one side if pedestrians must use equipment aisles.
  • Floors marked with walkway striping where barriers cannot be used.
• Install convex mirrors at blind aisle intersections.
• Restrict use of forklifts near time clocks, break rooms, cafeterias, and main exits, especially during peak times like the end of a shift or breaks.
• Install barriers so workstations are isolated from aisles traveled by forklifts.
• Post plant speed limits and traffic control signs.
• Invest in equipment with good warning systems. (Blue lights signal in front of and behind a forklift. Side warning lights create a bright line alongside a forklift, indicating to pedestrians to keep their distance.)

References

1. https://tinyurl.com/bd5wjxjn
2. https://tinyurl.com/4ktyv65r

Russell Niedzwiecki is Corporate Trainer for TrainMOR, a company dedicated to the safety of operators and their co-workers. He has provided powered industrial truck operator, mobile elevating work platform (MEWP) and Train the Trainer courses for more than 10,000 people for more than 800 companies throughout Michigan and Indiana. Visit: https://www.trainmor.com/ Morrison Industrial Equipment offers a mobile industrial tire service. Call 833-633-0256 for a free, no obligation tire survey.