The Bottom Line: The Optimal Distance for Palletizing
Posted on July 12, 2022 | in Ergonomics
VelocityEHS’ Blake McGowan starts a new series called “The Bottom Line”, which turns science into something you can immediately apply. Here, he discusses manual material handling and the optimal distance for palletizing.
Hi, my name is Blake McGowan, and I’m a certified professional ergonomist with Humantech (now VelocityEHS Ergonomics).
Today is the first in a series of videos called the “Bottom Line”.
What we’d like to do is take years of research and translate it into a very simple message that you can apply today, and one of the topics we’d like to speak about is one that I get asked about all the time, and that’s manual material handling, specifically lifting. And one of the most common lifting tasks is palletizing, placing an object onto a pallet.
When palletizing, there are three common things that we’re concerned about with regards to ergonomics. The first one is the force or the amount of weight that we’re lifting. The second is bending, back bending, and reaching postures. And the third is twisting.
Now, with regards to commonly applied and available tools, the NIOSH lifting equation does an excellent job helping us understand the acceptable force. There are also quite a few guidelines out there to help us put our hand working heights within the optimal zones.
Unfortunately, there’s not a lot of information to help us minimize back twisting. However, in 2014, Steve Lavender and his team of researchers from the Ohio State University, put together a very simple research study that helped us determine: what’s the acceptable amount of twisting and what’s the proper workstation layout? They had three primary findings, and they’re shown down here in this graph. When the first finding they showed is, as the distance between where you pick up an object and where you place it increases.
What we find is the amount of back twisting decreases, so there’s an optimal distance that will minimize the amount of back twisting, while loading something onto a pallet. They also found that when retrieving the object, the bending velocity at the start of that lift, unfortunately starts to increase as that distance starts to increase, so that’s not a good thing.
The last thing is that as the distance between the origin and the destination increases, so does the task time.
So, taking all that information into consideration, they found an optimal or ideal distance between the start of the lift and the end of the lift. The bottom line, the stuff that you need to do or apply right away in your workplace and understand is that the optimal distance between the origin of the lift and the destination or the pallet is between one and 1.25 meters away.
For more information about material handling, lifting, and other bottom-line videos, please visit our webpage at Humantech (www.ehs.com)