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Materials Handling: Heavy Lifting
 Lifting heavy items is one of the leading causes of injury in the workplace. In 2001, the Bureau of Labor Statistics reported that over 36 percent of injuries involving missed workdays were the result of shoulder and back injuries. Overexertion and cumulative trauma were the biggest factors in these injuries.
When employees use smart
lifting practices and work in their "power zone," they are less likely to suffer from back sprains, muscle pulls, wrist injuries, elbow injuries, spinal injuries, and other injuries caused by lifting heavy objects.
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| Weight of Objects |
Potential
Hazards:
-
Some loads, such as large spools of wire (Figure 1), bundles of conduit, or heavy tools and machinery place great stress on muscles, discs, and vertebrae.
-
Lifting loads heavier
than about 50 pounds will increase the risk of injury.
Possible Solutions:
-
Use mechanical means such as
forklifts (Figure 2) or
duct lifts to lift heavy spools, transformers, switch gear, service
sections, conduit, and machinery.
-
Use
pallet
jacks
and
hand
trucks
to
transport
heavy
items.
-
Avoid
rolling
spools.
Once
they
are
in
motion,
it
is
difficult
to
stop
them.
- Use suction devices (Figure 3) to lift junction boxes and other materials
with smooth, flat surfaces. These tools place a temporary handle that makes
lifting easier.
Use ramps or
lift gates to load machinery into trucks rather than lifting it.
Materials that
must
be
manually
lifted
should
be
placed
at "power zone"
height, about mid-thigh to mid-chest.
Special
care
should
be
taken
to
ensure
proper
lifting
principles
are
used.
Maintain neutral and straight spine alignment whenever possible. Usually, bending at the
knees, not the waist, helps maintain proper spine alignment.
Place
materials
that
are
to
be
manually
lifted
at
"power
zone"
height,
about
mid-thigh
to
mid-chest.
Maintain
neutral
and
straight
spine
alignment
whenever
possible.
Usually,
bending
at
the
knees,
not
the
waist,
helps
maintain
proper
spine
alignment.
Order
supplies
in
smaller
quantities
and
break
down
loads
off-site.
When
possible,
request
that
vendors
and
suppliers
break
down
loads
prior
to
delivery.
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Figure 1
A spool
holding
117
pounds
of wire.
Figure 2
Forklift.
Figure 3
Suction
tool.
Figure 4
Two-man
lift.
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- Prefabricate items in a central area where
mechanical lifts can be used. Only transport smaller, finished products to
the site.
-
Limit
weight
you
lift
to
no
more
than
50
pounds.
When
lifting
loads
heavier
than
50
pounds,
use
two
or
more
people
to
lift
the
load
(Figure
4).
-
Work
with
suppliers
to
make
smaller,
lighter
containers.
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| Awkward Postures |
Potential Hazards:
- Bending while lifting (Figure 5) forces the back to support the weight of the upper body in addition to the weight you are lifting. Bending while lifting places strain on the back even when lifting something as light as a screwdriver.
- Bending moves the load away from the body and allows leverage to
significantly increase the effective load on the back. This increases the stress on the lower spine and fatigues the muscles.
- Reaching moves the load away from the back, increases the effective
load, and places considerable strain on the shoulders.
- Carrying loads on one shoulder, under an
arm, or in one hand, creates uneven pressure on the spine.
-
Poor housekeeping limits proper access to objects being lifted, and forces
awkward postures.
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Figure 5
Employee twisting in
an awkward position. |
Possible Solutions:
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- Move items close to your body and use your legs when lifting an item from a low location (Figure 6).
- Store and place materials that need to
be manually lifted and transported at "power zone" height, about mid-thigh to mid-chest.
- Minimize bending and reaching by placing heavy objects on shelves, tables, or racks.
For example, stack spools on pallets to raise them into the power
zone.
- Avoid twisting, especially when bending forward while lifting. Turn by moving the feet rather than twisting the torso.
- Keep your elbows close to your body and keep the load as close to your body as possible.
- Keep the vertical distance
of lifts between mid-thigh and shoulder height. Do not start a lift below mid-thigh height nor end
the lift above shoulder height. Lifting from below waist height puts stress on
legs, knees, and back. Lifting above shoulder height puts stress on the upper back, shoulders, and arms.
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Figure 6
Different approaches
to lifting.
Figure 7
Aerial lift.
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- Use ladders or aerial lifts (Figure 7) to elevate
employees and move them closer to the work area so overhead reaching is minimized.
- Break down loads into smaller units and carry one in each hand to
equalize loads. Use buckets with handles, or similar devices, to carry loose
items.
- Keep the load close to the body. When lifting large, bulky loads, it may be better to
bend at the waist instead of at the knees in order to keep the load
closer to your body.
- Optimize employee access to heavy items through good housekeeping and
preplanning.
- Use roll-out decks installed in truck beds
to bring materials closer to the employee and eliminate the need to crawl into the back of a truck.
See the Vehicular Activities section for more information.
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| High-Frequency and Long-Duration Lifting
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Potential Hazards:
- Holding items for a long period of time, such as when installing fixtures or j-boxes (Figure 8), even if loads are light, increases risk of back and shoulder injury, since muscles can be starved of nutrients and waste products can build up.
- Repeatedly exerting, such as when pulling wire, can fatigue muscles by
limiting recuperation times. Inadequate rest periods do not allow the body to rest.
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Figure 8
Employee reaching
overhead.
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Possible Solutions:
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- Use a template made of a lightweight material (Figure 9) such as cardboard to mark holes for drilling when mounting heavy items such as junction boxes and service panels. This ensures that the heavier item does not need to be held in place to level and measure for anchor mounts.
- Provide stands, jigs, or mechanical lifting devices such as duct lifts
to hold large, awkward materials such as junction boxes and service panels
in place for fastening.
-
Rotate tasks so employees are not exposed to the same activity for too long.
- Work in teams; one employee lifts and holds items while the other
assembles.
- Take regular breaks and break tasks into shorter segments. This will
give muscles adequate time to rest. Working through breaks increases the risk of
musculoskeletal disorders (MSDs), accidents, and reduces the quality of work
because employees are overfatigued.
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Figure 9
Cardboard template for lighting fixtures.
Figure 10
A prefabricated electrical box. |
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Plan work activities so employees can limit the time they spend holding loads.
- Pre-assemble work items such as fixtures or boxes (Figure 10) to minimize the time employees spend handling them.
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| Inadequate Handholds |
Potential Hazards:
- Inadequate handholds (Figure 11) make lifting more difficult, move the load away from the body, lower lift heights, and increase the risk of contact stress and of dropping the load.
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Figure 11
Boxes without handles. |
Possible Solutions:
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-
Utilize proper handholds, including handles, slots, or holes (Figure 12), with enough room to accommodate gloved hands.
- Ask suppliers to place their materials in containers with proper
handholds.
- Move materials from containers with poor handholds or without handholds into containers with
good handholds.
- Wear proper personal protective equipment (PPE)
to avoid finger injuries and contact stress. Ensure that
gloves
fit properly and provide adequate grip to reduce the chance of dropping the load.
- Use suction devices (Figure 13) to lift junction boxes and other materials with smooth, flat surfaces. These tools place a temporary handle that makes lifting easier.
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Figure 12
Slots in boxes help in lifting.
Figure 13
Suction device. |
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| Environmental Factors |
Potential Hazards:
- Cold temperatures can cause decreased muscle flexibility, which can result
in muscle pulls.
- Excessively hot temperatures can lead to dehydration, fatigue, and
increased metabolic load.
- Low visibility or poor lighting (Figure 14) increases the chance of trips and falls.
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 Figure 14
Work space with window as only light source. |
Possible Solutions:
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- Adjust work schedules to minimize exposure to extreme temperatures.
- Wear warm clothing when exposed to cold temperatures.
- Drink lots of water to avoid dehydration in excessive heat.
- Provide proper lighting (Figure 15) for areas with low light and perform work during daylight hours.
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 Figure 15
Light stand illuminating the work area. |
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