622 Forklift Competent Person

Load Center and Rated Capacity

Load Center

The load center is the horizontal distance from the vertical face of the forks or attachment to the load's center of gravity.

For a uniformly distributed load, the load center is generally half the load dimension measured from the vertical face of the forks toward the load. For example, a 48-inch-long load positioned against the fork face has a 24-inch load center.

A forklift may be rated on its capacity plate to handle 4,500 pounds at a 24-inch load center. That does not mean the forklift can handle every 4,500-pound load. A longer load with its center of gravity farther from the fork face creates greater leverage and may exceed the forklift's rated capacity. The rated capacity of the forklift decreases as the length of the load increases.

Rated Capacity

Reading the Capacity Plate

In practice, operators use the forklift's capacity plate, also called a data plate, to determine whether a load is within the truck's rated capacity under the conditions specified on the plate.

OSHA 29 CFR 1910.178(a)(6) requires markings showing the truck's capacity, operation, and maintenance information, and 1910.178(o)(2) requires loads to be within the truck's rated capacity. Attachments and modifications can also affect capacity.

The examples below show that moving the load’s center of gravity farther from the fork face reduces the forklift’s rated lifting capacity. The ratings apply only to the truck configuration shown on the capacity plate.

• First Row: According to this capacity plate, the forklift can lift a load weighing up to 4,500 pounds when the load center is 24 inches and the lift height is 130 inches.
• Second Row: When the load center increases to 36 inches at the same 130-inch lift height, the forklift’s rated capacity decreases to 2,800 pounds.

In Practice: Using the Capacity Plate

Operators should always refer to the forklift's capacity plate for the manufacturer's capacity information rather than calculate load moment to determine whether a load is within the forklift's rated capacity. The information on load moment relationships in this course is included only to explain the principles of forklift stability and how increasing the load weight or load-center distance can reduce stability.

Before lifting a load, the operator should:

1. Determine the load weight. Check shipping documents, markings, labels, or other reliable information. Do not guess the weight of an unknown load.
2. Determine the load center. Determine where the load's center of gravity is located in relation to the vertical face of the forks or attachment. For a uniformly distributed load, the load center is generally half the load dimension measured from the fork face toward the load.
3. Check the capacity plate. Compare the load's weight and load center with the forklift's rated capacity and load center shown on the plate.
4. Check the truck's configuration. Make sure the capacity information applies to the forklift as it is currently configured. Attachments, such as side shifters or clamps, can affect capacity. Check the capacity information applicable to the truck and attachment combination. Under 29 CFR 1910.178(a), modifications or additions that affect capacity or safe operation involve manufacturer approval and corresponding changes to plates/tags/decals, and trucks equipped with non-factory-installed front-end attachments have specific marking requirements.
5. Consider the load's position and shape. Long, irregular, off-center, or unevenly distributed loads can have a different center of gravity and can affect the forklift's capacity and stability.
6. Do not exceed the rated capacity. If the load or operating condition does not match the capacity information shown on the plate, do not assume the forklift can handle it. Obtain the applicable manufacturer's capacity information before lifting.

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