The Arsenal Files 2/The Arsenal Files 2 (Arsenal Computer).ISO/health/ergofact.all

Text File | 1994-07-20 | 15KB | 353 lines

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                UNITED STATES DEPARTMENT OF LABOR
          Occupational Safety and Health Administration
_________________________________________________________________

                         ErgoFact No. 1

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MEATPACKERS "PULLING THE PADDLE BONE"
CREATE UNDUE ERGONOMIC STRESS


THE PROBLEM

Several recognized ergonomic risk factors (stressors) --
repetitive motions, awkward postures, and forceful exertions --
were present in one operation present in beef packing houses.

This operation involves pulling the paddle bone (part of the
scapula) away from the shoulder or chuck of the animal.  Several
workers complained of substantial pain; thus, a video tape
analysis was performed on this job.  As the meat is conveyed past
the workers, they hook the meat, and pull it to themselves, and
do minor fat trimming.  They then scribe or cut around the paddle
bone to separate it as much as possible from the meat.  These
cuts require both pushing and pulling the knife with the blade
extending from the little finger side of the hand.  The workers
then literally rip the meat from the bone by hooking it first
with the left and then the right hand.  They use their forearm to
brace against the meat and continue to tear at the meat with the
other hand.  They then grasp the neck of the bone with one hand
and pull with great force while pounding the hook into the gap
between the meat and bone.

After more cuts are made to separate the bone completely the bone
is discarded to a conveyor.  The entire operation requires about
thirty seconds to complete.

The workers at these positions experienced low back pain, pain in
both shoulders, and severe pain in both hands.  The tasks exposed
workers to ergonomic stressors that caused cumulative trauma
disorders.  These included repeated deviations of the wrists,
shoulders, and back.  High pushing and pulling forces at the hand
and elbow and repeated pounding of the palm area of the hook hand
were also significant stress contributors.


THE SOLUTION

The task was modified by changing it into two jobs.  As the meat
is conveyed by the work stations the first worker scribes the
bone as before but does not attempt to separate the bone from the
meat.  A second worker places a circular hook over the neck of
the bone and this hook is chained to the floor.  As the conveyor
and attached meat continues to move, the slack in the chain is
taken up and the bone is pulled away from the meat mechanically.
The bone is then removed from the hook and placed on another
conveyor.

THE BENEFITS

The workers on these jobs are no longer exposed to the excessive
ergonomic stress previously present.  The manning for the job
remains essentially the same as several workers were performing
the task; however, they are now free to rotate between the jobs
to provide some variety and reduce their exposure to any
remaining force and repetition stressors.  The costs were less
than $300 per work station for materials and installation.  The
workers all felt that the changes made their job much less
demanding and at no loss of output.
_________________________________________________________________
NOTE:  ErgoFact provides a brief summary of the results of an
employer's recognition of the need for workplace safety and
health assistance to eliminate ergonomic hazards.  In some i-
nstances, these situations were recognized by enforcement
officials during an inspection. Safety and health assistance can
identify and help the employer correct workplace hazards, develop
or improve an effective safety and health management system, or
both. For more information on ergonomics contact the OSHA office
in your area.

Your company or workplace is eligible to receive one free copy of
this leaflet which you may duplicate and share with your co-
workers. To be placed on the distribution list, send request with
your title and address to ErgoFacts, OSHA, Room N-3647, 200
Constitution Avenue, Washington, D.C. 20210.

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                UNITED STATES DEPARTMENT OF LABOR
          Occupational Safety and Health Administration
_________________________________________________________________

                         ErgoFact No. 2

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PUNCH PRESS OPERATION CREATES UNDUE
ERGONOMIC STRESS


THE PROBLEM

Three recognized ergonomic risks factors (stressors)--repetitive
motions, awkward postures, and forceful exertions--were present
in one operation used by a metal parts manufacturer.

The job required the simultaneous feeding of small metal parts
into a punch press.  The parts were supplied to the press by two
slide conveyors which approached the operator from the rear and
stopped approximately two and one-half feet from the press.  The
operator would reach down and back with both hands simultaneously
to pick up parts from the conveyors, reach forward to place the
parts in the press, and finally raise both hands up to the top of
the press to actuate two palm buttons.  Upon completion of the
press operation, the finished parts were ejected out the back
side of the press and the cycle repeated throughout the work
shift.

The employer received numerous complaints of upper extremity pain
and discomfort from the operator who made regular requests to be
removed from this particular job.  Thus, an ergonomic analysis of
the work methods and workstation was conducted.  A video tape of
the operation was made and the operator was interviewed to find
where he was experiencing pain.

The operator experienced moderate pain at the wrists, hands and
fingers and severe pain at the shoulders.  Motion analysis noted
that the task required simultaneous extended reach behind the
operator's back, blind groping for and grasping of the conveyed
parts, and moving them approximately four feet to the press,
placing the parts into the press with precision, then reaching
above head height to actuate the press with the two palm buttons.

The operator then brought his arms down rapidly to the conveyors
behind him as the cycle was repeated.


THE SOLUTION

Three primary work station changes were suggested, evaluated, and
implemented to reduce the range of exertions previously required.

First, the conveyors were extended in length to end closer to the
press and just forward of the operator.  This allowed the
operator to reach down in his field of view and easily grasp the
metal parts.  Hinges and handles were installed on these exten-
sions to allow easy access to and from the workstation.

The second change was the simple installation of a platform to
elevate the worker to allow him easier access to the press which
then brought it to just below chest height.


Finally, the two overhead palm buttons were replaced by light
beam actuators.  This redesign reduced reach distances, reach
heights, grasping problems, hand forces, overall fatigue, and
joint stress points as well as cycle time.


THE BENEFITS

The operator was no longer exposed to the three stressful
situations present before modifications.

Also, the operator was freed from the symptoms which originally
alerted management to the problem and caused the operator to want
to be removed from the particular job.

The cost of fabricating and installing the conveyor extensions
and the light actuators was approximately $700.

The employee now enjoys his work situation, an indication that
the job is considerably less stressful.
_________________________________________________________________
NOTE:  ErgoFact provides a brief summary of the results of an
employer's recognition of the need for workplace safety and
health assistance to eliminate ergonomic hazards.  In some i-
nstances, these situations were recognized by enforcement
officials during an inspection. Safety and health assistance can
identify and help the employer correct workplace hazards, develop
or improve an effective safety and health management system, or
both. For more information on ergonomics contact the OSHA office
in your area.

Your company or workplace is eligible to receive one free copy of
this leaflet which you may duplicate and share with your co-
workers. To be placed on the distribution list, send request with
your title and address to ErgoFacts, OSHA, Room N-3647, 200
Constitution Avenue, Washington, D.C. 20210.

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                UNITED STATES DEPARTMENT OF LABOR
          Occupational Safety and Health Administration
_________________________________________________________________

                         ErgoFact No. 3

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TUBE BENDING OPERATIONS CREATE UNDUE
ERGONOMIC STRESS ON HANDS


THE PROBLEM

Tubes used in air conditioning need to be bent to a special
configuration.  Previously, this job required a series of steps.
First, the operator manually inserted the tube into the fixture
and then secured the tube using two clamps.  Secondly, the
operator applied a one-handed upward push on the lever arm of a
crimping tool used to bend the tube.  Finally, the operator used
both hands to bend the other tube around the post and back over
the tube unit.  This final task required the operator to use
his/her left hand to press the end of the tube into the fixture
while using the right hand to press the tube against the lower
part of the fixture.

Workers involved in this process complained of stress on fingers,
hands, and wrists.  These stresses, which were identified through
an ergonomic job task analysis, included:

  * Awkward posture and bending of the wrist joint;

  * Forceful pinch grips with the fingers used to bend the tube;

  * Mechanical stress on the palm of the hand used to operate the
    crimping tool;

  * Forceful exertion of the thumb to clamp and hold the tube in
    place; and

  * Awkward position of the elbows and shoulders to operate the
    crimping tool.


THE SOLUTION

The work was repositioned to reduce postural stress on the
operator's hands.  The fixture was placed closer to the edge and
to the operator.  This eleminated the long reach required during
both the initial bending and the final, tighter bending of the
tube against the fixture.

To reduce the force exerted by the thumb, the plate with bending
pegs was rotated 30 degrees clockwise on the work surface.

The fixture was lowered approximately 3 to 4 inches from its
original height in order to lower the operator's working elbow
height.  The fixture was also tilted 30 degrees toward the
operator to minimize awkward posture and bending the wrist.

Foot rails were installed to support the operator's while he/she
is seated.


Finally, foam padding was added  to the handle of the crimping
tool's lever arm to reduce the amount of mechanical stress that
the handle placed on the palm during the tool's operation.


THE BENEFITS

Employees have suffered less postural and mechanical stress on
fingers, hands, and wrists.  Complaints and workman's
compensation costs have been reduced.
_________________________________________________________________
NOTE:  ErgoFact provides a brief summary of the results of an
employer's recognition of the need for workplace safety and
health assistance to eliminate ergonomic hazards.  In some
instances, these situations were recognized by enforcement
officials during an inspection. Safety and health assistance can
identify and help the employer correct workplace hazards, develop
or improve an effective safety and health management system, or
both. For more information on ergonomics contact the OSHA office
in your area.

Your company or workplace is eligible to receive one free copy of
this leaflet which you may duplicate and share with your co-
workers. To be placed on the distribution list, send request with
your title and address to ErgoFacts, OSHA, Room N-3647, 200
Constitution Avenue, Washington, D.C. 20210.

**********************************************************************************************************************************

                UNITED STATES DEPARTMENT OF LABOR
          Occupational Safety and Health Administration
_________________________________________________________________

                         ERGO FACT NO. 4

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LIFTING OPERATIONS CREATE
ERGONOMIC STRESS ON BACK

Lifting heat exchangers (part of residential boiler units) from
the floor to a conveyor line resulted in low back pain and back
injuries to employees working on an assembly line.

THE PROBLEM

The job involved one employee who placed the heat exchangers on a
conveyor from a pallet on the floor for assembly of residential
boilers.  The units were brought out in batches, ten at a time,
with about 30 units being handled each day.

The cabinets and insulation for the boilers were placed on the
conveyor first, then the employee lifted and positioned the heat
exchangers manually.

Three moves were necessary to position the unit after the heat
exchangers were brought to the work area on pallets.  The first
required the employee to lift the unit from the pallet and place
it on the floor near the conveyor.  The second required the
employee to lift the unit from the floor to the conveyor.  The
worker then had to place one hand under the unit and lift to
shift the unit into its final position.

The job was evaluated using the National Institute for
Occupational Safety and Health (NIOSH) lift guide ("Work
Practices Guide for Manual Lifting," Department of Health and
Human Services, NIOSH, 1981). The first and third lifts were
determined to be outside the parameters of the NIOSH lifting
guidelines, so only the second lift was evaluated.

The units range in weight from 61 to 84 pounds.  After the
variables of the second lift were measured and entered into the
NIOSH lifting equation, the action of lifting the heat exchangers
from the floor to the conveyor line fell between the Action Limit
(28 pounds) and the Maximum Permissible Limit (85 pounds) which,
under the guidelines, calls for engineering (mechanical) or
administrative (work practice) controls.

THE SOLUTION

For this situation, the company installed a hoist that eliminated
the three manual lifts of the heat exchanger, instead
mechanically lifting exchangers off the pallets and positioning
them along the assembly line.

THE BENEFITS

The workers in this job are no longer exposed to hazards of
overexertion injuries with the three stressful lifts thus
eliminated.  The employees were receptive to having this easy-to-
handle lifting aid installed.

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