NIOSH Equation

NIOSH’s equation advises companies on acceptable weight limits for lifting tasks, carrying loads and manual handling which, according to its designer, would protect almost all workers from associated back trouble from raising and lowering.

The goal is to provide operators with a tool to increase their effectiveness in the prevention of pain in the lower back body part.

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The NIOSH equation can be used to assess two-handed lifting and lowering tasks, including their impact on the back.

It is especially useful in the case of workers who lift loads whose weight is always the same.

It can be useful in any work environment where workers perform tasks of lifting or lowering inert loads (i.e. excluding handling living things) with both hands.

The NIOSH equation takes into account biomechanical factors and duration.

Restrictions & limits

The NIOSH equation does not take into account whole-body vibration or the risks of MSDs that are not associated with raising or lowering.

The method cannot be used in the following cases:

  • Lifting or lowering with one hand, on slippery floors or in unfavorable conditions (tight spaces …), in a seated or kneeling position, of unstable objects, people or animals;
  • Tasks performed for more than eight hours;
  • Transport, push or pull tasks (including using a wheelbarrow or shovel).