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Stacking Height Guidelines

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					Stacking Height Guidelines
There are a few guidelines that address safe stacking heights for different materials, such as:

Two proposed solutions are:

       Reducing the stacking height; or
       Use of a Bliss box for extra strength, which will allow packages to be stacked even higher.

Factors that Affect Stacking Height

Having said all of that, and being a consultant, my answer to the question about safe stacking height
has to be, "It depends." To determine a safe height, you need to address these questions:

       What are you stacking?
       What kind of container is it in?
       What is the gross weight of the package?
       How many packages can be stacked on top of one another before the bottom fails?
       What is the loading capacity of the floor? The deck? The shelving?
       What are the temperature and humidity conditions for storage?
       How will these conditions affect the packaging? The product?

You also need to consider safety and ergonomic issues:

       How will the package be handled - by hand or with equipment?
       Will the stack have to be broken down by hand?
       If so, will the employee have to reach overhead? Repeatedly?
       If a package falls from a height, how hazardous is it if it hits an employee on the head, the
        shoulder? With or without a hard hat?

Next is the AHJ - Authority Having Jurisdiction and building codes:

       Will the AHJ allow you to store that much material in your space?
       Is there a hazard to storing that material?
       Do you need fire wall separations?
       Do you need special ventilation?
       Do you need classified locations and explosion-proof wiring and fixtures?
       Do you need XP materials handling equipment?

The Dangers of Improper Stacking

Stacking items until they fall is a game some of us played as children. Then, as we got older, we
stacked playing cards to form houses. When the pile came tumbling down, it was all for laughs. But
in the workplace, properly stacking materials is no game.

When officials investigated the worker's death, they identified three contributing factors:
      Overfilled tote bags;
      Untied tote bags; and
      Double-stacked tote bags unsupported at outside edges.

When items are double-stacked, the bottom item must provide a flat and sturdy foundation for the
item above. In this case, the tote bags were overfilled. Consequently, the bags were rounded on the
top. Result: The stack was unstable.

12 Ways to Stack Mismatched Items

To prevent stacked materials from falling, collapsing, rolling or sliding, you must plan the stack. You
need to consider the object's weight, size and shape, as well as its accessibility. Securing stacked
bagged or round objects is especially tricky. Here are 12 pointers for stacking such seemingly
unstackable items:

   1. Try to keep articles of the same size and weight together.
   2. Keep heavy and/or unstable items nearer to the floor.
   3. Secure bags and bundles by stacking them in an interlocking pattern or in alternating
       directions to increase stability.
   4. Ensure that all bags are properly closed, to prevent items from spilling or shifting.
   5. Place barrels, balls, rolled material and metal bars in racks to prevent them from rolling.
   6. If you don't use racks, stack round items on solid, level surfaces.
   7. Block and chock bottom tiers of drums, barrels and kegs to prevent rolling or shifting in
       either direction.
   8. Band together large cylindrical objects that are stacked vertically.
   9. If you're using racks to stack long items, don't let parts protrude past the end.
   10. Place planks, sheets of plywood or pallets between tiers to provide a firm and flat surface.
   11. If materials can't be stacked due to size, shape or fragility, store them on shelves or in bins.
   12. Stack only to safe heights.

Stack It Right

When stacking, be conscious of:

      Height limitations;
      Clearance from sprinkler heads;
      Access to aisles, exits and emergency equipment;
      Safe loading levels;
      Damaged shelving or pallets; and
      Incompatible ingredients in cylinders or barrels

Pallet jack may not be the most hazardous piece of equipment in your workplace. But its simple
appearance can be dangerously

deceiving. Manual pallet jacks have been the culprit behind crushed toes, scraped knuckles and
pulled backs. Improperly stored and these devices also pose tripping hazards. If your facility uses
pallet jacks, share these safety tips with your workers.
Wear Proper PPE

Workers who work with pallet jacks need to wear appropriate personal
protective equipment, including:

       Safety-toed footwear to prevent foot injuries caused by being run
        over by the wheels, being hit by materials falling from the jack or
        stubbing a toe on the jack;
       Gloves to reduce the risk of cuts, bruises and blisters; and
       Safety eyewear to prevent injuries from material strapping and
        hazardous chemicals being moved.

Maintain the Pallet Jacks

After a while, the solid rubber wheels of pallet jacks can develop wear, resulting in unstable loads
and poor handling. In turn, workers can experience stress to the hands and arms because of
difficulty steering and stopping the device.

Periodic maintenance of pallet jacks will enable workers to operate the devices with the minimum
amount of hand, arm and finger force.

Maintain the Pallets Too

Keeping your pallets in good condition may sound trivial, but it's not. Using a damaged or defective
pallet can have serious consequences. For example, it can cause a load to shift and fall, resulting in
injury. It's important to inspect pallets before using them.

Follow these Safe Handling Guidelines

Here are some tips for workers to keep in mind when using a pallet jack:

       Check the floor for ruts, bumps and other imperfections;
       Never place your feet under a pallet jack;
       If your view is obstructed, have a co-worker guide the load;
       Never exceed a pallet jack's load capacity;
       Don't use a pallet jack for human transportation;
       When going down an incline, push, don't pull;
       Stick to correct traffic lanes, and be alert to avoid collisions around corners;
       Be aware of pinchpoint hazards to your hands; and
       Use proper lifting techniques when loading and unloading.



Store Them Properly

When not in use, store pallet jacks where they will not create tripping hazards. And make sure that
the devices do not block exits or emergency equipment, such as fire extinguishers
Push, Don't Pull

Is this safe? Absolutely NO! The human body is meant for pushing, not pulling. It would seem that
your workers need a little training in body dynamics. A local Physical Therapist or Occupational
Therapist should be able to help.

Clearly this is a difficult task when what you are moving can move anyway it wants. But my
instructions were pretty simple: when the load (patient) is on the stretcher push don't pull, the strain
on your back, shoulders, wrists and arms is tremendous.

Pulling May Lead to Back Injuries

Pallet jacks are designed to be pushed. They are not designed to be pulled by one or both arms. If
employees are pulling pallet jacks, they are using their backs more than their legs to move the load.
They tend to bend forward creating a curvature in their spine making them more susceptible to back
injuries. By pushing the load, they can keep their back and spine straight, using the stronger and
larger muscles and bones in their legs to apply the force necessary to move the load. Pallet jacks
should not be pushed except to make small adjustments in the positioning of the load, while
standing erect.

You Can Push More Than You Can Pull

The one thing that concerns me the most is that a person can push almost 4 times what they can
pull and if a worker feels it's necessary to use both arms to pull then the worker is probably
overexerting and at risk for a lower back injury or a shoulder injury while pulling the pallet jack. Has
anyone ever seen a person pull a car that is stuck in the snow to get it going? We have an inherent
logic about pushing because we know that we are stronger when we push with our legs, which is the
same principal as lifting with our legs rather than our back, but too many workers pull pallet jacks
because they don't think about the body mechanics involved. Using both arms to pull a pallet jack
behind yourself is also a recipe for being run into by the pallet if you have to stop suddenly. It is
impossible to always push a pallet jack but pulling should only be allowed to position the pallet for
moving not for actually moving the pallet around.

Pushing Gives You More Control

Many of our employees were trained in material handling including the proper use of pallet jacks.
Throughout the training (about 4 hours in duration), it was repeated that you should always push,
never pull a pallet jack.

Yes, it will put un-necessary strain on the back and shoulders, not to mention the potential of a
more serious tripping/falling hazard should the worker's foot make contact with the wheels or the
load while pulling a pallet jack backwards.

Also, you can have & maintain much more control over the jack and the load by pushing it. You can
steer/maneuver away from obstacles easier than pulling, and when needed, you can stop it a lot
quicker, too.
This would be good to put in writing as part of your company's written safe work practices and
procedures and have the workers sign of that they understand this and they are warranted to follow
company policies and procedures.

Pushing Works Better But Takes Practice

It is easier on the back and arms if you push the load rather than pull a load. Reason employees will
pull a load with a manual pallet jack is it's easier to steer the pallet. It takes practice but if you push
the load you are using less effort and it is easier on the body; lower back, arms, shoulders legs. Ask
your employees to spend the day pushing instead of pulling and see if they notice the difference at
the end of the day. They may be surprised!

How to Push Properly

Hand Trucks (Dollies)

When hand trucks, dollies, Pallet Jack or special lifting devices are used to move containers or large
tires for example, push the hand truck whenever possible instead of pulling it. Pushing uses leg
muscles instead of back muscles in order to reduce risks of back injuries

       if a hand truck must be pulled, do so with a steady force
       do not jerk it up curbs or steps
       do not ride on hand trucks
       do not walk backwards when pulling
       inspect hand trucks and other lifting devices prior to each use

The Hazards of Pulling

Biomechanically, pulling with two arms is safer, in the sense that the spine is kept more in alignment
during the work. One-armed pulls twist the torso, and also put a lateral torque on the muscles of the
lower back. They also put a huge strain on the elbow joint if heavy loads are frequently moved in
this fashion. Workers also tend to have a "blind side" when using the one armed pull, as they tend to
not twist their heads to look directly in front of them (to fully see the line of travel). The restricted
peripheral vision is on the side opposite of the hand used to pull. They may not see loads, objects or
personnel approaching from this side.

There are also risks in pulling something in a trailing fashion with both arms however. During the
work, most employees will tend to bend over, especially when first beginning the pull in order to
overcome the inertia of the resting load. If the worker loses traction or trips, he has no means to
catch himself with both hands positioned far behind the back. At best, he or she will have an
extended fall before a hand or arm can be brought out.

It is very likely under these circumstances that more serious hand, arm, shoulder and even facial
injuries will be incurred. Also it is noteworthy that if loads are being moved down an aggressively
sloping floor, the pallet jack can "run away" if the worker loses concentration on his task, and roll
forward far enough to strike the feet and lower legs.
Use Electric Equipment and Mind the Toes

Safety professionals teach that the preferred method for applying force is to push, rather than pull a
load, but with manual pallet jacks, that practice is hard to follow. As a specialist and expert witness
in forklifts and materials handling, I will say that in practical usage, both pushing and pulling are
necessary to move, transport, and place a load. This is why electric pallet jacks were invented, to take
the strain off the body and be able to move heavy loads safely and efficiently.

Getting back to the specific question of whether it is better to use two arms or one arm to pull the
load, the way I see it, it would depend on the individual's strength and weight. To move a "dead"
load and keep it moving, takes a certain amount of force applied, both for movement and control. If
an individual is more comfortable using two arms rather than one to accomplish the task, then they
are distributing the load with more equal force on their body than with just one arm, and are in a
better position to control the load.

Keep in mind that users of manual pallet jacks should wear safety toe shoes, and be taught to drop
the load, by using the hydraulic release lever, if the load gets out of control. Ramps and inclines
present specific hazards and should be avoided.

Conclusion

Just like for PPE, you need to perform a hazard assessment to determine the answers. If you're
purchasing products, ask the manufacturer what their recommendation on stack height is. If you're
the manufacturer, you will need to do some actual tests to make that determination. I

				
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