Looking for a quick, simple, easy to use table to assess ergonomic job hazards?  Consider using The Liberty Mutual Tables.

Dr. Stover Snook and Vincent Ciriello from Liberty Mutual developed a set of tables identifying the maximum acceptable weights for pushing, pulling, and carrying tasks for both males and females. The Liberty Mutual tables consider the following variables:

• Height of the hands from the floor (simplified as mid-thigh, waist, or chest level for pushing and pulling and elbows bent or elbows straight for carrying).
• Frequency (there are a limited number of frequency options and the analyst must choose the closest available frequency).
• Distance (similarly there are a limited number of distance options and the analyst must choose the closest available distance).

The reasons we like these tables are:
• Clear goal to design a task for at least 75 percent of the population.
• They are formatted in simple, one-page layouts that are easy to use.
• A task is either acceptable or not (removes ambiguity of a yellow or in-between score).

The two main limitations of the tables are: 
• They are based on psychophysical ratings of industrial work groups, not strength or probability of injury.
• They are only used to rate one task at a time, not the cumulative effect of handling tasks.

Despite these, the tables are a good method to assess a job for ergonomic hazards associated with pushing, pulling, and carrying. Please contact us if you'd like to learn more about the Liberty Mutual Tables and their effective use as a risk assessment tool in the workplace.