By Carol Heffernan, CPE
A common misconception is that material handling injuries are associated primarily with lifting and lowering In fact, the 2012 Liberty Mutual Workplace Safety Index reported that 26.8% of overexertion injuries in the workplace were caused by excessive lifting, pushing, and pulling, as well as holding and throwing Furthermore, these injuries were considered disabling, as they resulted in approximately 6 days away from work It is predicted that over one million workers will suffer a back injury in 2013 Although these numbers appear to be staggering, very little has been done to address these issues The percent reduction in overexertion injuries has been approximately 0.5% per year over the last decade.
It is often said, “If you cannot shake hands with the work, it is unfriendly.” There are two simple principles to keep in mind as you look to reduce risk for manual material handling tasks First, consider the vertical location of the work. Ideally, material handling tasks should be located between 38″ and 49″ from the standing surface, or in the “handshake zone.” Overall, the acceptable vertical range is from 24″ to 62″ from the standing surface The second principle is to consider the horizontal reach to the work For frequently performed tasks (more often than twice per minute), the recommended horizontal reach to the work is 11″ to 16″ (from the front of the work surface) For infrequently performed tasks, the horizontal reach should be no more than 22″.
With these material handling guidelines in mind, the following are a few low-cost alternatives:
- Double- or triple-stack pallets to raise working heights.
- Provide three-sided access to pallets and work to minimize horizontal reaching.
- Vertically stack products to raise the grasping height.
- Elevate shelving and racking off the floor surface to minimize bending.
Another category of overexertion injuries includes pushing and pulling tasks The guidelines for these types of tasks include continuous vertical handles on the cart or object In addition, to maintain work in that handshake zone, handles should be mounted at a height between 38″ and 45″ from the floor and placed 18″ apart As a general rule, pushing is preferred over pulling, as operators are able to maintain clear visual access in the direction of motion when pushing.
The following are a few low-cost design considerations that will minimize the required push and pull forces:
- Wheel diameter of at least 8″
- Harder caster composition with a crowned tread
- Swivel front wheels for pulled carts
- Swivel back wheels for pushed carts
Checking the “handshake” for your material handling tasks is the first step toward reducing your risk for overexertion injuries in the workplace.
This library resource is located in the following industry type(s): Ergonomics