From The Ergoweb® Learning Center

New Liberty Mutual MMH Equations (2021) Added to Ergoweb Enterprise

Peter Budnick, PhD, CPE

Liberty Mutual Insurance Company has conducted numerous studies over several decades that help identify and reduce risk of injury related to manual material tasks like lifting, pushing and carrying. Many of the studies were led by researchers Snook and Ciriello, and the resulting ergonomics data and assessment methods are often referred to as the “Snook Tables,” or “Snook and Ciriello Tables,” usually referring to publications dating back to 1991. However, there were gaps in the data, and the Liberty Mutual team continued to conduct studies over the years, resulting in the new Liberty Mutual MMH Equations (2021).

The team, including Snook, Cieriello, Maynard and Brogmus, collaborated with researcher Potvin to publish an updated, more inclusive compilation of the data in the form of predictive equations. Ergoweb quickly embraced this new evidence based ergonomics and has added several new tools to its Ergoweb Enterprise™ ergonomics management system:

  • 2021 Liberty Mutual Equations for Lifting and Lowering Tasks
  • 2021 Liberty Mutual Equations for Pushing and Pulling Tasks
  • 2021 Liberty Mutual Equations for Carrying Tasks

Ergoweb’s version of these new tools allows analysts to set design goals and specify the percent of the working population that should be able to handle the loading conditions.

When assessing a specific handling condition like a lifting task, the equations predict the % Capable for any load you specify. For example, you might specify your design goal as 75% female population being capable of the lifting task, and the equations will let you know what weight would be acceptable. Or, you can test your known lifting weight, and the equations will predict the % of the working population that will actually be able to handle that weight in the specified conditions

If the analyst is in the design exploration stage, and is not yet sure what the actual loads will be, the tools will predict the load value that will accommodate at least 75% of the female working population, a commonly accepted goal in workplace design, and allow the analyst to explore different lifting conditions until they find an acceptable solution.

Example Liberty Mutual Equation Results Screenshots from Ergoweb Enterprise™

liberty mutual equations
liberty mutual equations
Screenshot showing a Fail result for a specified lifting task with a load weight of 30 lb.
liberty mutual equations
Screenshot showing a Pass for an initial force measurement of 35 lb. in a pushing task, and a Fail for the sustained force measurement of 30 lb.
liberty mutual equations
Each tool delivers detailed results showing which lifting factors contributed the most to the risk. This example is from the Liberty Mutual Equations Push / Pull tool.

About Ergoweb Enterprise™

Ergoweb Enterprise™ is a cloud-based, software as a service ergonomics management platform that helps companies continually improve their ergonomics programs, and helps comply with OSHA and international standards such as the ISO 45001 health and safety management systems. It flexes to meet varying employer needs, from simple turn-key systems, to complex configured processes for large employers. Our objective is to help you create workplaces with fewer injuries, optimized productivity, and higher quality.

With the addition of these new tools, the system now includes 20 evidence-based workplace ergonomics assessment and design tools, as well as an extensive library of training and problem solving resources. Schedule a demo to learn how Ergoweb can support your ergonomics requirements.

Stay tuned, we’ll be announcing more new tools soon!