From SCDigest's On-Target E-Magazine
- July 17, 2013 -
Supply Chain News: The Fatigue Factor in Labor Management and Engineered Standards
Many Companies Apply Simple Flat Allowance, but More Nuanced Calculation is Usually Better; Personal, Fatigue and Delay Factors
SCDigest Editorial Staff
The essence of Labor Management Systems in distribution is the calculation of goal times for each task a worker performs, based on the specific details and ergonomics of that piece of work (discrete engineered standards).
But there are certainly many nuances to standards development and resulting goal time calculations. One of the most important of those is how so-called "fatigue" factors are applied to standards, under the logical assumption that as a shift proceeds, workers are inherently likely to be less productive as they tire.
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Companies should also have a bias towards simplicity, such that the approach is both fair and understandable to DC workers. |
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What Do You Say?
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SCDigest asked several LMS experts for their thoughts on the process, and as with many issues in supply chain its clear LMS users have a number of considerations to work through to get this right.
It starts with understanding that fatigue is almost always factored into standards overall from the get go, says Mark Messinger, director of services for labor management at Manhattan Associates.
"All companies with engineered standards include a fatigue factor, as standard industrial engineering practice," Messinger says. In other words, standards are first developed based on how long the task should take in sort of unconstrained mode, but then modest relaxation of the goal times is then applied based on the fact engineers know there will be some fatigue, Messinger says.
He added that there are standard industrial engineering tables that are used to apply this factor based on task type, usually adding a 3-5% factor for expected fatigue.
It gets a little bit more complicated after that.
For example, fatigue is often combined with other factors that are used to relax goal times, generally grouped under what are called Personal, Fatigue and Delay (PF&D) allowances.
Beyond fatigue alone, "Personal time is generally considered to be about 5% of the working day for all task types and delay time [factors in DC processes that get in the way of doing a task] typically ranges from 2% to 4% by task type," according to Tom Stretar, a director at consulting firm enVista.
Stetar observes that there are many factors specific to a given DC operation and task that have to be considered to come up with the right fatigue allowances. Those include physiological factors (weights of products being handled, posture required for the task, etc.), psychological factors (concentration level required, level of monotony), and environmental factors (how hot it is inside the DC).
Nafe Hagen of JDA Software offered the following example of how these differences play out in practice: "A case picker on a double pallet jack in a general merchandise warehouse would and should have a different fatigue allowance calculation than a putaway driver on a forklift in a freezer warehouse," Hagen told SCDigest. "The case picker exerts a lot of physical effort handling cases whereas the forklift driver has less physical fatigue but the environmental fatigue factor is higher."
The purpose of all of this, says Manhattan's Messinger, is to provide a standard that is fair and equitable for worker and company.
The PF&D approach is "especially useful in environments where the amount of time worked or amount of weight lifted can vary. It can also be used to give an additional allowance at certain times of day, for example in the heat of the afternoon," Messinger told SCDigest "If these types of variability are present in your distribution environment, what we call progressive PF&D is a good way to account for that variance. If this variance is not significant, fatigue time can simply be applied evenly throughout the day."
(Distribution/Materials Handling Story Continues Below
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