The 80/20 Rule and Warehouse Ergonomics

Because of the nature of the work, pickers can suffer all sorts of ailments including shoulder, elbow, wrist, hand, and back injuries.  (Courtesy: Jim Crosslive at flickr.com)
Because of the nature of the work, pickers can suffer all sorts of ailments including shoulder, elbow, wrist, hand, and back injuries.
(Courtesy: Jim Crosslive at flickr.com)

If you’ve been involved in business for any length of time, then you probably have heard of the 80/20 rule. What it means is that in anything a few (20%) is crucial and many (80 percent) is trivial. Business managers would interpret this as 20 percent of the work eats up 80 percent of time and resources. A traffic manager may surmise that 20 percent of the problems on the road is due to 80 percent of the drivers. A clothing designer may make the rule relate by observing that 20 percent of the clothes in one’s closet are worn 80 percent of the time. A restaurant owner could presume that 20 percent of his restaurant’s menu accounts for 80 percent of the sales.

A warehouse manager knows that there are products in his stock that can be defined as “high movers” or sell in higher volume than other products. Thus, using the 80/20 rule, a warehouse manager could conclude that 20 percent of products stored in his warehouse is picked 80 percent of the time.

So how can a warehouse manager apply this rule and make his warehouse personnel perform more efficiently?

Look around your warehouse. What do you see? You see rows and rows of shelves. Some shelves are as tall as 30 to 40 feet while others are just a few feet high. As a warehouse manager, you know what products are the “high movers.” Wouldn’t it be best to store this 20 percent of your inventory in locations of easiest accessibility to maximize efficiency and lessen wasted time?

Another major concern for warehouse managers is the workforce. If a large number of workers, especially pickers, are injured on the job and cannot work as a result, then you’re staring at additional costs that affects your bottom line.

The Occupational Safety and Health Administration (OSHA) and the National Institute for Occupational Safety and Health (NIOSH) and especially human resource managers in warehouses know that due to the nature of the work warehouse employees suffer sudden acute accidental injuries and chronic injuries due to repetitive motion and awkward positioning.

NIOSH regularly perform studies to ascertain the risks warehouse employees are subject to due to their job demands. What they have discovered is that metabolic rates, lumbar movements performed during common warehouse tasks and the average frequency of lifting a common load of 30.4 pounds can all result in health issues for those employees.

As a result of their normal working activity, employees suffer injuries to shoulders, elbows, wrists, hands, and backs.

Issues that cause these problems can be fixed.

Consider this: a baseball player standing in the batters box waiting for a pitch has a strike zone. So does a warehouse employee who is tasked with picking orders. The strike zone for a standing warehouse picker is the area between his shoulders and his knuckles. If he is required to reach below his knuckles, he must flex his hips to reach downward. Such a position forces the worker into poor posture. Moreover, studies have shown that performing a task in which a picker has to reach below his knuckle height takes 3.2 times as long as performing the task within the strike zone.

If the worker has to reach above his shoulders, which is above the strike zone, his shoulders must move above the body and that causes the bending of the back, which increases the risk of low back and shoulder injuries.

All of this can be avoided with the proper design of shelves and storing the “high move” products to areas in the workers’ strike zone.

Perhaps it is asking too much for all “high move” products to be stored in areas of shelves within the workers’ strike zone. It’s not practical. The plan should be to store heavier and high-use products within the strike zone and place lighter and low-use items in locations that may be out of the strike zone.

The result of this strategy will be happier employees who will be more productive and efficient in their jobs.