• How can the vertical distance affect the weight limit?

How can the vertical distance affect the weight limit?

Example: A worker lifts a 15 kg load from loosely piled pieces of metal from the floor to the table five times an hour.

To calculate the recommended weight limit (RWL) for the task:

• Determine the weight of the load.

Weight - 15 kg

• ASSESS the six components of the lifting task.

H (Horizontal Distance) - 30 cm
V (Vertical Distance) - 0 cm
D (Lifting/ carrying Distance) - 115 cm
F (Frequency) - 12 min
A (Angle) - 0°
C (Coupling/quality of grip) - poor

• Select the numeric multiplier factors for each component of the task from the tables in Calculating Recommended Weight Limit (RWL).
• Determine the Recommended Weight Limit for the task. Refer to Assessing Relevant Handling Factors and Calculating Recommended Weight Limit (RWL).

23 Kg x 0.80 x 0.80 x 0.86 x 1.00 x 1.00 x 0.90 = 11.4 kg

• Compare weight of the box against the determined Recommended Weight Limit for the task. The weight of the load at 15 kg is higher than the recommended weight limit calculated to be 11.4 kg.

Therefore the TASK IS DANGEROUS.

Recommendations

• Assess which of components of the task contribute most to the risk. Refer to Assessing Relevant Handling Factors.

The components: V - starting height, D - lifting distance and H - horizontal distance and C - poor grasp contribute similarly to the risk.

• Raise the starting height by providing materials at the best starting height (75 cm). This change also decreases D, the lifting distance.

Evaluate the Redesigned Task

• Assess the six components of the task in redesigned layout.
• Determine the new Recommended Weight Limit. Refer to Assessing Relevant Handling Factors.

23 kg x 0.8 x 1.00 x 0.95 x 1.00 x 1.00 x 0.90 = 15.7 kg

• Compare weight of the load against the Recommended Weight Limit in new layout.

The weight of the load at 15 kg is lower than the recommended weight limit now calculated to be 15.7 kg.

• Further improvement can be achieved by providing the working materials in containers with handles; this would increase RWL up to 17.5 kg.

Therefore, MOST WORKERS CAN SAFELY PERFORM THE TASK.

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Document last updated on November 21, 2002

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