| Management and staff employees should be aware of good work practices that minimize
the possibility of injury. Items such as the patterns for pallet
unloading, break schedules, training, or the number of hours worked can
greatly influence the potential for injury.
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Potential
Hazards:
| Selectors
encounter many racking situations in the typical warehouse
and often depalletize in ways that expose them to unnecessary
stressors. Depalletizing is where material is removed
from a pallet where it has been stacked, usually in multiple
layers. There are two common techniques of depalletizing
(layer-by-layer and pyramiding) and either technique may
be used depending on racking and product types. |
Fig. 1:
Bending required to reach boxes.
Fig. 2:
Pyramid depalletizing method. |
- In a layer-by-layer technique selectors remove all
cases from one layer before the cases from the next
layer are removed (Fig. 1). This technique requires
employees to reach to the back of a palletized load
and pull an item forward. This process moves the load
closer to the body prior to lifting, but it can also
create back and shoulder hazards if cases are extremely
large or heavy. Also, weak or small handles, stacks
above shoulder height, or cases that do not slide
easily can stress the shoulder, back, and possibly
the knee during reaching and pulling motions.
- In the pyramiding technique cases are removed in
a diagonal pattern from the top front to the rear
back (Fig. 2). This technique is preferred when weight,
size, and handle types are like those mentioned above.
In these situations the employee can limit forward
reaching and pulling by moving closer to the load
and lifting the closest container, often leaving the
remaining stack in a pyramid shape. Pyramiding is
not suggested if the pallet is unstable or in an area
with little clearance space for employees. Many of
the new racking systems, such as the push-back model,
are elevated on slides and tightly packed into a pick
slot. These configurations limit stability and accessibility,
forcing employees to reach considerable distances
across empty portions of the pallet to access and
lift loads. Even lighter loads can create considerable
stress to the shoulder, back, and knee when held away
from the body.
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Possible
Solutions:
- An evaluation of each racking situation should be
performed either by management or by a trained employee
to determine the least stressful method of depalletizing.
An appropriate selection should consider the nature
of the load, the weight of the load, and the type
of racking system used.
- Employees should generally use a layer-by-layer
technique in push-back racking systems where employee
access is limited, and pyramiding creates longer
reach distances. Examples best suited for layer-by-layer
depalletizing are:
- Boxed product, preferably with handles or
cutouts
- Lighter boxes that slide fairly easily
- Product stacked below shoulder height (measured
with the pallet on the rack)
A layer-by-layer approach can be made easier
using the following methods:
- Use a hook to pull product from the back of
pallets, allowing the arm to stay closer to
the body, and reducing stress to the shoulder
- Order product, such as bagged produce, with
slip sheets between the layers to facilitate
sliding
- Order produce in boxes rather than bags. Boxes
are easier to slide than bagged product and
boxes are usually packaged in smaller quantities
so the overall package is lighter.
- Place a slip sheet made of low friction material
on partially emptied layers to facilitate sliding
of product from the back of the pallet
- Pyramiding on a push-back system may be acceptable
for lighter product such as toilet tissue or styrofoam
plates. Product on push-back systems should be
stacked low enough so reaches above head height
are not required.
- Pyramiding may be acceptable for heavier items
or items that do not slide easily, such as bagged
onions, if the pallet is placed on the floor or
another solid support that provides adequate access
and the pallet itself does not present a hazard
if walked on to provide easier access. Plastic pallets
will provide a better base than wood slat pallets.
Fig. 3:
Push-back rack system |
- For lighter loads stacked above shoulder height,
it may be possible to use a combined approach. The
top layers can be pulled down the sides in a controlled
fall using the pyramid technique. When stack height
drops below shoulder level, product can be removed
in a layer-by-layer fashion.
- If a push back system is to be used with a pyramiding
technique, equip it with a positive lock mechanism
such that the pallet is held firmly in place and can
not be pushed backward if an employee steps on it.
This will allow employees to place one foot on the
pallet to improve access and limit reaches. These
postures will still not be acceptable for heavy product
such as most meat items.
- Tag slots as to what type of technique should be
used and train employees about both the tagging system
and selecting techniques.
- Develop systems so employees keep product that
has to be lifted closer to the body, minimizing reaches
and torso bending
- Utilize a turntable in bays so pallets can be
rotated to ensure that the product is close to
the aisle prior to lifting
- Create space around palletized loads so employees
can access product from the side keeping it close
to the body prior to lifting
- Develop a product re-orientation process for
unloading using the pyramiding technique. The
turning process should turn the pallet around
180 degrees to improve access. This will place
the empty portion of the pallet at the back of
the slot and place product closer to the aisle.
This can be done by replenishing personnel during
the stocking process or by a designated individual
assigned to this task.
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Potential
Hazard:
- Selectors tend to reach across the pallet with
a load in the hand (Fig. 4) rather than walk around
a pallet. This prevents keeping the load close to
the body and adds significant stress to the shoulders
and upper back.
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Fig. 4:
Selector reaching with a load in hand.
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Possible Solutions:
- Factor proper work practice into pick times. Time
limits should not force employees to use shortcuts
like reaching across a pallet instead of walking
around the pallet for better access.
- Provide training to Selectors so they understand the
importance of performing tasks using proper ergonomic
techniques.
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Potential
Hazards:
- Even experienced Selectors will come upon
situations where they must perform unexpected exertions.
This can happen when:
- A box weighs more
than expected.
- The box falls apart (Fig. 5), creating the
need to perform quick and unexpected actions to
save the load.
- Boxes stick
together and additional force is needed to
separate the boxes.
- Poor footing or slippage causes the load to be supported in an unexpected
or awkward posture.
- Quick motions occur while holding the load.
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Fig. 5:
Crushed, unstable boxes.
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Possible Solutions:
- Tag slots with case weights. This can be
accomplished by noting the case weight on the slot in
clear and easily read terms, or by color coding the
slot to indicate the hazard. For example, the area in front of the slot can be marked
with a red marker to indicate those areas where the
heaviest product is stored.
- Request that the suppliers pack product in sturdy
cases, appropriate for the environment.
- Clean all areas in the stocking aisles to avoid slipping.
Workers should be educated on the importance of
appropriate footwear.
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Potential
Hazards:
- Stickers are placed on boxes after they are selected.
Often an employee holds the sticker sheet while selecting
and lifting product. If employees hold these
sheets while performing lifting tasks (Fig. 6), their
contact with the box is reduced. This can lead to
slippage and unexpected exertions, which increase
the chance of injury to the back and shoulders.
- One hand may exert more force than the other, which can lead to
uneven weight distribution. This increases the chance of injury to the back. The chance of straining
the tendons of the hand or forearm is also increased.
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Fig. 6:
Lifting while holding
labels in one hand.
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Possible Solutions:
- Use a sticker dispenser that can be worn around the
employee's waist. This device will
allow Selectors to use both hands when lifting
product.
- Provide a clipboard on the pallet jack to hold the
sticker sheets rather than having employees hold the
sheets in their hand while lifting.
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Potential
Hazard:
- Selectors may work through their break periods if
production standards are set too high. Breaks are very
important in heavy, physical work. Without periodic
rest periods, the body may not have adequate time to
rest and recuperate. Selectors who consistently work
through their breaks are at a greater risk of
musculoskeletal disorders (MSDs), accidents, and
reduced quality of work due to operating at higher
fatigue levels.
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Possible Solutions:
- Work rates that require Selectors to pick orders
rapidly will benefit the company, in the short run, by
reducing the number of Selectors hired. However,
these benefits may be lost due to higher injury
rates if work
standards exceed the capabilities of individuals. A competent work-time consultant
can survey work tasks
and recommend an appropriate
work rate.
- Ergonomic improvements may not justify an increase
in pick rates. The benefits of
reduced risk could easily be lost if rates are
increased because the task appears to be easier.
- Incorporate a work ramp-up (break-in)
period for new
hires. Work rates set for experienced Selectors may be
too high for those that are new to Selecting work. It
is common practice to allow a gradual ramp-up work
rate for new hires that increases production over
several weeks, or until employees can work at the same
pace as experienced workers.
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Potential
Hazard:
- Working overtime, especially when the overtime
is performed as an extension of the normal
workday, may overexert employees by exceeding
their capabilities.
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Possible Solutions:
- Minimize overtime if at all possible. Provide
part-time staff for peak periods.
- Schedule overtime on off-days instead of
extending the regular work shift. This will allow a period
of recovery between shifts when employees may
recuperate.
- Assign overtime on a volunteer
basis as much as possible.
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Potential
Hazard:
- Selectors are on their feet for long periods of
time, possibly an entire shift. The
leg muscles continually support the body, which can
cause fatigue. Employees work on hard concrete
surfaces, which can create contact trauma or tendon
and muscle problems if proper footwear is not
worn.
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Possible Solutions:
- Educate employees about proper footwear. Shoes
with solid support, flex at the ball of the foot, and adequate
padding will maintain foot support and provide shock absorption against foot
strike while walking on hard
concrete surfaces.
- Provide employees with padded shoe inserts that support the foot and
cushion
against foot strike.
- Shoes with non-skid soles are also
important, particularly where surfaces are
potentially slippery.
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Potential
Hazard:
- Without a medical management program, the
presence of musculoskeletal disorders (MSDs)
will probably be underestimated. With reduced
awareness of MSDs, symptoms may go
undetected until they become disabling injuries. Injured
employees are less likely to get timely and appropriate care
and restricted duty programs may not be established or
utilized if proper medical management is not in place.
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Possible Solutions:
- Consult with a medical specialist who
has experience in and is familiar with work-related
musculoskeletal disorders (MSDs). This person may be a physician, a nurse, or
other healthcare provider that is
familiar with causes of musculoskeletal injuries. They should be allotted time to track
injury trends, coordinate injured employee's visits
to healthcare facilities, interact with the
treating physicians, and interact with the
ergonomic committee regarding return-to-work
activities and restricted work jobs. This person
can also act as the principle contact person for
Workers Compensation issues, and the liaison between
management, healthcare and employees.
- A relationship should be developed with a local
medical clinic if an on-site specialist is not an
option. It is imperative that the healthcare
professionals be familiar with the type of tasks
the employees perform. This will assist in
diagnosis and the return-to-work process after
an injury. If a clinic is used, it is important to
have a responsible party on-site
to act as a liaison with the medical provider.
- A return-to-work program should be developed
for placement of injured workers
into jobs consistent with their medical
restrictions. A well constructed plan allows
employees to return to work sooner and increases the
chance that they will eventually return to
their original job. The challenge of such a plan
is to develop and categorize jobs within a
facility that do not violate the restrictions
given by the physician. Care should be taken to
develop such a program in cooperation with any
worker's unions, medical staff and contractors.
- Symptoms should be reported as soon as they
start to develop. Early reporting can help address
potential problems
before they become serious and costly lost-time
injuries.
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Potential
Hazard:
- Newly hired employees may not recognize
ergonomic hazards or understand effective techniques used to
minimize these hazards.
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Possible Solutions:
- Provide general ergonomics training and work-task specific training at the time of new-hire
orientation. Explain risk factors and proper work
techniques to minimize these hazards.
- Provide appropriate video tapes of proper work
practice for employees to review on a regular basis.
In addition to regularly scheduled refresher
training, injured employees should be retrained
regarding ergonomic risks pertinent to their injuries.
Provide Post Incident Refresher Training
after injuries.
- Provide new employees with a mentor that can
provide insights on the proper and
most efficient methods to perform their tasks.
- Explain the medical management system to
new-hires. It is important for employees to
understand how to report an injury and how the
company prefers its employees to seek medical
attention. This can
expedite assistance, reduce costs, and improve
lines of communication.
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