In 1991 S.H. Snook and V.M Ciriello published “The design of manual handling tasks”, informing about their studies on manual handling of loads.
The Snook and Ciriello tables (1991) establish the Maximum Acceptable Weights and Forces Values for a certain percentage of the population in given conditions. When a general assessment of the risk level is carried out, acceptable forces must be considered, and when the initial or sustained forces are excessive for 90% of the population using the task, the task must be considered as high risk.
Once the Maximum Acceptable Weight has been obtained for the situation we are studying, its value will have to be corrected if special circumstances occur such as the load has no handles or the load is handled at a distance from the body.
- If the load has no handles or does not permit an acceptable grip the Maximum Acceptable Weight must be reduced by 15%.
- If the load is handled at a distance from the body the Maximum Acceptable Weight must be reduced by 50%.