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Horizontal Distance Multiplier Factor

How can the horizontal distance affect the weight limit?

Example: A worker lifts 15 kg boxes from the table to the shelf five times an hour. Notice that there is a barrier between the worker and the box.

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

  • Determine the weight of the load.

Weight equals 15 kg

H (Horizontal Distance) - 50 cm
V (Vertical Distance) - 70 cm
D (Lifting/Carrying Distance) - 40 cm
F (Frequency) - 12 min
A (Angle) - 0°
C (Coupling/quality of grip) - fair

The revised NIOSH Lifting Equation is: 23 Kg x HM x VM x DM x AM x FM x CM= RWL

23 Kg x 0.50 x 0.99 x 0.93 x 1.00 x 1.00 x 1.00 = 10.59 kg

  • Compare the weight of the load against determined Recommended Weight Limit for the task:

The recommended weight is 10.59 kg, which is less than the current weight at 15 kg.

Conclusion

The weight of the load is 15 kg, which is higher than the calculated recommended weight limit of 10.59 kg.

Therefore, this task is likely to increase the risk of a lifting related injury.

Recommendations

The critical component is H, the horizontal distance of the box from worker's body.

  • Remove the barrier to allow worker to get closer to the box (horizontal distance is now 30 cm which uses a factor of 0.83).
Removing the barrier allows worker to get closer to the box

Evaluate the Redesigned Task

The revised NIOSH Lifting Equation is: 23 kg x HM x VM x DM x AM x FM x CM = RWL

23 kg x 0.83 x 0.99 x 0.93 x 1.00 x 1.00 x 1.00 = 17.58 kg

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

The weight of the load at 15 kg is now lower than the recommended weight limit of 17.58 kg.

Therefore, MOST WORKERS CAN SAFELY PERFORM THE TASK.

Document last updated on May 27, 2021

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Although every effort is made to ensure the accuracy, currency and completeness of the information, CCOHS does not guarantee, warrant, represent or undertake that the information provided is correct, accurate or current. CCOHS is not liable for any loss, claim, or demand arising directly or indirectly from any use or reliance upon the information.