Ergonomics done right.®
June 13th, 2008

People are flexible, but…

Wally Bock raises an interesting point in "Designing work as if people mattered" at his Three Star Leadership blog. Unlike the specs for say a carriage bolt, people’s "specifications" vary and therefore job descriptions must take that variability into account.

As Wally points out, carriage bolts do not change after we buy them, and they are consistent in size and Guby strength. People are not. That is why employers have an obligation to understand the capabilities and limits of human performance and ensure that work tasks and the work environment fit within the normal operating range of a person.

If you utilize a carriage bolt outside of it’s tolerances, it will not perform consistently and will wear out. When a person operates outside of their physical capabilities for force, posture, frequency, and duration, they too will wear out. The visible result of wearing out is often not that visible. Wearing out may take the form of presenteeism (at work but not working to potential), absenteeism, injuries or illness. Furthermore, degrading human performance may show up in reduced productivity or quality. The most visible sign, injury, as akin to the carriage bolt breaking, and that is too late.

The bottom line is; base your expectations (flexible expectations) of what people can do on a solid understanding of human limits and capabilities. By eliminating stressors through a "best-fit" workplace, employees can concentrate on what they do best: make decisions, diagnose problems, inspect work, etc.

Where does one find the limits and capabilities of humans (i.e. operating specs for employees)? Anthropometric tables, static anthropometry, strength tables, and ergonomic design guidelines provide acceptable ranges for reaching, grasping, pushing, pulling, pressing, lifting, and more.

Two questions to ponder:

  • Do you often put machinery into production without heeding the specs?
  • Do you track your maintenance programs by how much of your machinery breaks or fails?

Just because a human CAN do the job as designed, doesn’t mean the job was well designed for a human. People are flexible, but don’t hold that against them!