ONLINE self-study

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ONLINE self-study

• Machine Guarding

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Machine Guarding

• The following online training course provides
  employees with machine guarding information
  concerning processes, equipment, and operations
  that are specifically conducted at UNC Chapel
  Hill.
• Employees will be introduced to the different
  types of machine guarding methods, types of
  motions and actions, and preventative strategies,
  and procedures to follow when using machine
  guards or in the absence of machine guards.
• Additional machine guarding information not
  covered in detail within this particular training
  can be found at www.osha.gov and under the UNC
  IMAC Manual Machine Guarding Policy.
• References Covered in Training
• OSHA 29 CFR 1910.212 (General Requirements for
  All Machines).
• Machine Guarding OSHA e-Tool.

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Introduction

• According to OSHA there are approximately 18,000
  amputations, lacerations, crushing injuries, and
  abrasions per year. There are also 800 deaths
  per year that are associated with improper or no
  machine guarding. The majority of these types of
  injuries and deaths could have been prevented by
  having proper machine guarding in place.
• Machine guarding is the method used to prevent
  body parts and unwanted objects from coming
  into contact with moving or dangerous parts of
  machinery. If machine guarding is not in place,
  serious bodily harm or death could occur.
• Machine guarding is required by OSHA for any
  machine part, function, or process that has the
  potential of causing an injury. Machine guarding
  also differs for every machine due to the varying
  physical characteristics and the operators
  involvement in how the machine is ran.

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Introduction

• Employees often work with job specific types of
  machines long enough that it becomes second
  nature to operate the machine. This can become
  potentially hazardous since
• Continuous repetition can lead to a lack of
  concentration when operating the machine.
• The operator believes that they are skillful
  enough with the piece of equipment that the
  machine guard is not needed and they proceed to
  remove the guard.
• A dangerous situation is created in both of these
  scenarios for the operator and employees that may
  be working around the machine during the time of
  operation.
• Never take for granted the security of working
  with the same machine. Remember to always be
  alert and conscious of all moving machine parts
  no matter how simple the operation of the machine
  may be.

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Introduction

• Types of injuries that have the potential of
  occurring from improper or no machine guarding
  are
• Pinched, crushed, or severed limbs such as
  fingers, toes, hands, feet, arms, or legs.
  Several examples of machines on campus that have
  the potential for causing these types of injuries
  include Trash compactors, lawn mowers, printing
  machines, power saws, wood cutting machines,
  metal cutting machines, etc.
• Eye injury or blindness. Examples of machines on
  campus that have the potential for causing these
  types of injuries include Abrasive wheel
  grinders, table saws, portable power saws, drill
  presses, etc.
• Cuts, punctures, or abrasions. Types of machines
  that may cause these types of injuries include
  Drill presses, table saws, various wood working
  machines, metal forming/cutting machines, etc.

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Introduction

• Hazardous activities are considered to be
  situations that may present a potential hazard to
  the operator or employees working around the
  machine during operation. Examples of hazardous
  activities while operating any machine includes
• Normal production operations.
• Machine set-up/threading/preparation.
• Machine inspection.
• Clearing jams.
• Machine adjustments.
• Cleaning of machine.
• Lubricating of machine parts.
• Maintenance of machine.
• Do not wear loose clothing or jewelry, the
  material may become entangled or caught in the
  machine. Once caught, these items can cause the
  employee to become entangled in or pulled into
  the machine.

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Components of Machines

• A machine consist of three basic mechanical
  components
• Point of Operation.
• Power Transmission Devices.
• Operating Controls (Other Moving Parts)
• Note Even though machines have these three
  basic components, this does not mean that every
  machine has the same machine guarding.

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Components of Machines

• Point of Operation Where work is performed on
  the material. Points of operation must be
  machine guarded. (i.e. - Cutting, forming, etc.)
• Power Transmission Devices This is the
  mechanical component that transmits energy to the
  part of the machine that performs the work. (i.e.
  - Flywheels, pulleys, belts, connecting rods,
  etc.)
• Operating Controls (Other Moving Parts) Are all
  of the parts on a machine that move while the
  machine is operating. (i.e. - Reciprocating,
  rotating, etc.)

Operating Controls
Power Transmission Device
Point of Operation
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Other Examples
Power Transmission Devices properly being guarded
on an S Drive Machine
Point of Operation on a Bench Grinder
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Other Examples
Guard
Point of operation being properly guarded on a
drill press
Operating controls on a drill press
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Hazardous Motions

• There are 4 types of hazardous motions that are
  associated with machines
• Rotating Motion.
• Reciprocating Motion.
• Transverse Motion.
• In-running Nip Points (Pinch Points)

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Hazardous Motions

• Rotating Motion Is a circular motion that is
  generated from a variety of mechanisms on
  machines.
• Rotating parts on a machine can grab an
  employee through minor contact which can force
  the hand, arm, or any other body part into a
  dangerous position. The danger increases when
  projections such as set screws, bolts, nicks,
  abrasions, and projecting keys are exposed on
  rotating parts. The danger also increases if
  loose clothing is being worn or if an employee
  has long hair.
• Collars, couplings, cams, clutches, flywheels,
  shaft ends, spindles, meshing gears, and
  horizontal or vertical shafting are some examples
  of common rotating mechanisms which may be
  hazardous.

Rotating Shaft End
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Hazardous Motions

• Reciprocating Motions Is a back-and-forth or
  up and-down motion that can strike or pin an
• employee between a moving part and a fixed
• object.
• Can be hazardous because, during the
  back-and-forth or up-and-down motion, a worker
  may be struck by or caught between a moving part
  and a stationary part. An example of this would
  be a forming machine.

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Hazardous Motions

• Transverse motion This refers to movement in a
  straight and continuous line. This type of motion
  creates a hazard because a worker may be struck
  or caught in a pinch or shear point by the moving
  part. An excellent example of a transverse
  motion would be a conveyor belt or belt sander.

Belt Sander
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Hazardous Motions

• In-Running Nip Points Pinch points develop when
  two parts move together and at least one moves in
  a circular motion. In-running nip points occur
  when machine parts move toward each other or when
  one part moves past a stationary object. (ex.
  Gears, rollers, belt drives, and pulleys)
• Pinch point hazards are caused by rotating parts
  on machinery. There are 3 main types of
  in-running nip points
• Parts can rotate in opposite directions while
  their axes are parallel to each other. These
  parts can either be in contact with one another
  or within close proximity. Examples of parts
  that rotate in opposite directions are gears,
  rolling mills, and calendars.

Sheet Metal Roller
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Hazardous Motions

• 3 Main Types (contd)
• Nip points are also created between rotating and
  tangentially moving parts. Examples of this type
  would be the point of contact between a power
  transmission belt and its pulley, a chain and a
  sprocket, and a rack and pinion.
• Nip points can also occur between rotating and
  fixed parts which create a shearing, crushing, or
  grinding action. Several examples of this
  include spoke hand wheels or flywheels, screw
  conveyors, or the periphery of an abrasive wheel
  and an incorrectly adjusted work rest and tongue.

Nip Point
Pulley
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Hazardous Actions

• The 4 types of hazardous actions that are
  associated with machines are
• Cutting Action.
• Punching Action.
• Shearing Action.
• Bending Action.

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Hazardous Actions

• Cutting Action May involve rotating,
  reciprocating, or transverse motion.
• The danger of cutting action exists at the point
  of operation where finger, arm, and body injuries
  can occur, and where flying chips or scrap
  material can strike the head, face, and eyes.
  Hazards are present at the point of operation
  when cutting wood, metal, or other materials.
• Several examples of mechanisms involving cutting
  hazards include bandsaws, circular saws, boring
  and drilling machines, turning machines (lathes),
  and milling machines.

Router
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Hazardous Actions

• Punching Action Results when power is applied
  to a slide (ram) for the purpose of blanking,
  drawing, or stamping metal or other types of
  materials.
• The danger of this type of action occurs at the
  point of operation where stock is inserted, held,
  and withdrawn by the employee.
• Examples of machines used for punching operations
  are power presses and iron workers.

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Hazardous Actions

• Shearing Action When power is applied to a
  slide or knife that is used to trim or shear
  metal or other materials.
• The hazard occurs at the point where the employee
  inserts, holds, or withdraws the stock by hand.
• Examples of machines used for shearing operations
  are mechanically, hydraulically, or pneumatically
  powered shears.

Guard
Shear
Metal Shear with proper guard in place.
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Hazardous Actions

• Bending Action Occurs when power is applied to
  a slide in order to draw, turn, or stamp metal or
  other materials into a specified shape.
• A hazard occurs at the point of operation where
  stock is inserted, held, and withdrawn.
• Equipment that uses bending action includes power
  presses, press brakes, and tube benders.

Tube Bender
Manual Break (Bends Sheet Metal)
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Safeguarding Requirements

• All safeguards (machine guards) must meet or
  exceed the following 6 requirements set forth by
  OSHA
• Prevent Contact.
• Be Secured to the Machine, Floor, Wall, etc.
• Protect from Falling Objects.
• Does NOT Create a New Hazard.
• Does NOT Create an Interference.
• Allows for Safe Lubrication.

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Safeguarding Requirements

• Prevent Contact The safeguard must prevent
  hands, feet, arms, legs, or any other part of the
  body from making contact with dangerous moving
  parts.
• A good safeguard system eliminates the
  possibility of the operator or another worker
  placing his hands near hazardous moving parts.
  The best practice is to interlock machine control
  and guards so the machine is inoperable unless
  the guards are in place.
• Be Secured to the Machine, Floor, Wall, etc.
  Workers should not be able to remove or tamper
  with the safeguard. A safeguard that can easily
  be made ineffective is not a safeguard at all.
• Guards and safety devices should be made of
  durable material that will withstand the
  conditions of normal use. They must be firmly
  secured to the machine.

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Safeguarding Requirements

• Protect From Falling Objects The guard should
  ensure that no objects can fall into moving
  parts. (Example A small tool which dropped
  into a machine that is spinning in a cyclical
  motion could cause the object to easily become a
  projectile (flying object) that could strike
  someone, and cause serious injury.)
• Does NOT Create a New Hazard A safeguard
  defeats its own purpose if it creates a hazard of
  its own, such as a shear point, a jagged edge, or
  an unfinished surface which can cause
  lacerations.
• The edges of guards should be rolled or bolted in
  such a way that they eliminate sharp edges.

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Safeguarding Requirements

• Does NOT Create Interference Any safeguard
  which impedes a worker from performing the job
  quickly and comfortably may be used improperly to
  make the job easier or even discarded while the
  work is being conducted.
• Proper safeguarding can actually enhance
  efficiency by relieving the stresses placed on
  the employee of thinking about the possibility of
  an injury when using an unguarded or improperly
  guarded piece of equipment.
• Allows for Safe Lubrication If possible, one
  should be able to lubricate or service the
  machine with the safeguard in place.
• Locating oil reservoirs outside the guards with
  lines leading to the lubrication points will
  reduce the need for the operator or maintenance
  workers to enter the hazardous area.

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Safeguarding Requirements

• OSHA Maximum Permissible Openings for Guards

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Other Machine Guarding Aides

• Machine guard aides include
• Safety Trip Controls.
• Gates.
• Photoelectric Barriers/Light Curtains.
• Awareness Barriers.
• Special Hand Tools.

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Other Machine Guard Aides

• Safety Trip Control
• Safety trip controls provide a quick means for
  deactivating the machine in an emergency
  situation.
• A pressure-sensitive body bar, when depressed,
  will deactivate the machine. If the operator or
  anyone trips, loses balance, or is drawn toward
  the machine, applying pressure to the bar will
  stop the operation.
• Other examples include emergency stop buttons,
  and emergency pull cords.

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Other Machine Guarding Aides

• Gates
• The gate is a moveable barrier that protects the
  operator at the point of operation before the
  machine cycle can be started. Gates are designed
  to be operated with each machine cycle.
• To be effective
• The gate must be interlocked so that the machine
  will not begin a cycle unless the gate guard is
  in place.
• The gate must be in the closed position before
  the machine can function. If the gate is not
  permitted to descend to the fully closed
  position, the machine will not operate.

Gate on an automatic bottle washer
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Other Machine Guarding Aides

• Photoelectric
• The photoelectric (optical) presence-sensing
  device uses a system of light sources and
  controls which can interrupt the machine's
  operating cycle. These are also known as light
  curtains. If the light curtain is broken, the
  machine instantly stops and will not cycle. This
  device must be used only on machines which can be
  stopped before the worker can reach the danger
  area. The design and placement of the guard
  depends upon the time it takes to stop the
  mechanism and the speed at which the employee's
  hand can reach across the distance from the guard
  to the danger zone.
• Once the light barrier is broken, the equipment
  must not be restarted while any employee is in
  the danger zone.

Photoelectric Barriers
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Other Machine Guarding Aides

• Awareness Barrier Serves as a reminder to a
  person that he or she is approaching the danger
  area. Even though the barrier does not
  physically prevent a person from entering the
  danger area, it calls their attention to it.
• Awareness barriers are not considered an adequate
  means of prevention when continual exposure to
  the hazard exists. An awareness barrier can be
  used in conjunction with a proper guard, but
  should never be the only method of guarding an
  area.
• For an employee to enter the danger area, an
  overt act must take place, meaning, the employee
  must either reach or step over, under or through
  the barrier.
• An example of this would be a highly visible tape
  placed on a table saw a few inches away from the
  point of operation.

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Other Machine Guarding Aides

• Special Hand Tools Are tools used specifically
  for placing and removing material to permit easy
  handling of material(s) without the operator
  placing a hand in the danger zone (i.e. Push
  stick, push block, etc.).
• Special hand tools should never be used in the
  place of other required guards. They can,
  however, be used in conjunction with the required
  machine guard. (i.e. Push stick used for a
  table saw in conjunction with a self adjusting
  table saw guard.)

Push Block
Push Stick
Fingerboard
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Construction of Machine Guards

• Most machine guards can be purchased from the
  manufacturer of the specified machine.
• Always check with the manufacturer of the machine
  to see if they also produce safeguards for that
  particular machine. Guards designed and installed
  by the builder/manufacture offer two main
  advantages
• They usually conform to the design and function
  of the machine.
• They can be designed to strengthen the machine in
  some way or to serve some additional functional
  purposes.

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Construction of Machine Guards

• Examples of Manufacturer Machine Guards

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Construction of Machine Guards

• Sometimes a guard is not produced by the
  manufacturer for a particular machine because the
  machine pre-dates the use or production of
  machine guards.
• If this is the case, then user built guards can
  be developed to serve the purpose of machine
  guarding as long as they are fabricated to
  function effectively and meet the specifications
  of proper machine guarding for the specific
  machine they are developed for.
• Note Just because a guard is not specifically
  made for a machine, does not mean a guard does
  not have to be in place.
• Machine guarding is required on ALL machines
  where a risk of an injury exists at the point of
  operation, or where exposed mechanisms/parts on
  the machine may injure an employee if a guard is
  not in place.

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Construction of Machine Guards

• Examples of Fabricated Machine Guards

Before
Before
After
After
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Machinery Maintenance Repair

• Having superior maintenance and repair procedures
  (i.e. Job Safety Analysis, Standard Operating
  Procedures) in place to reduce hazards can
  contribute significantly to the safety of UNC-CH
  maintenance personnel and machine operators. The
  following 4 things can make safe maintenance and
  repair work difficult
• The variety and complexity of machines to be
  serviced.
• The hazards associated with their power sources.
• The special dangers that may be present during
  machine breakdown.
• The severe time constraints often placed on
  maintenance personnel.

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Machinery Maintenance Repair

• The following safeguarding measures should be
  taken in order to prevent hazards while servicing
  machines
• Notify all affected employees (usually machine or
  equipment operators or users) that the machine or
  equipment must be shut down to service the
  machine or perform maintenance.
• Stop the machine.
• Isolate the machine or piece of equipment from
  its energy source.

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Machinery Maintenance Repair

• The following safeguarding measures should be
  taken in order to prevent hazards while servicing
  machines (contd)
• Lockout/Tagout the energy source.
• The danger of accident or injury is greatly
  reduced by shutting off and locking out/tagging
  out all sources of energy.
• Relieve any stored or residual energy.
• Verify that the machine or equipment is isolated
  from the energy source.
• Once all maintenance and repair has been
  completed, place and secure ALL guards back on
  the equipment before turning it on.

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Machinery Maintenance Repair

• The following list are exceptions to the general
  rules in regard to safeguarding measures that
  should be followed in order to prevent hazards
• When the servicing or maintenance is not
  hazardous for an employee. The supervisor,
  employee, or UNC Environment, Health Safety can
  deem servicing/maintenance as hazardous or
  non-hazardous. If there is a safety concern,
  contact UNC Environment, Health Safety before
  any servicing/maintenance is started.
• When the servicing which is conducted is minor in
  nature.
• Servicing is done as an integral part of
  production.
• The employer utilizes alternative safeguards
  which provide effective protection as required by
  29 CFR 1910.212 or other specific standards.

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Machinery Maintenance Repair

• The following list of specific steps must be
  followed in order to return the machine or piece
  of equipment to service. These steps include
• Inspection of the machine or equipment to ensure
  that all guards and other safety devices are in
  place and functional.
• Checking the area to ensure that energization and
  start up of the machine or equipment will not
  endanger employees.
• Removal of the lockout devices.
• Re-energization of the machine or equipment.
• Notification of affected employees that the
  machine or equipment may be returned to service.

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Feeding Ejection Methods

• Automatic Feed The material is fed from
  rollers or another automatic method.
• This eliminates the need for operator involvement
  in the danger area.
• Other guards such as fixed barrier guards are
  required for operator protection.
• Requires frequent maintenance due to the many
  moving parts involved in the automatic feed
  process.
• A disadvantage is that it may not be adaptable to
  different types or sizes of materials.
• Semiautomatic Feed Material is fed by chutes,
  movable dies, dial feed, plungers, or sliding
  bolster.

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Feeding Ejection Methods

• Automatic Ejection The material is ejected by
  air or mechanical means. This method of ejection
  may create a hazard of blowing debris.
  Disadvantages of the automatic ejection method
  include
• The size of materials limits the use of this
  method.
• Air ejection may present a noise hazard.
• Semiautomatic Ejection The material is ejected
  by mechanical means which are started by the
  operator. The operator does not have to enter
  danger area to remove material. Disadvantages of
  this method are
• That other guards are required for operator
  protection.
• It may not be adaptable to different sizes and
  shapes of materials being used.

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Feeding Ejection Methods

• Robotic Machines Used to perform work that is
  usually conducted by a human.
• Operator does not have to enter danger area.
• Are suitable for operations where high stress
  factors are  present, such as heat stress and
  noise levels 85 dB or higher.
• Disadvantages of Robots
• Can create hazards themselves.
• Require maximum maintenance.
• Are suitable only to specific operations.

Pegasus Robotic Bedding Machine
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Feeding and Ejection Methods

• Robotic Machines (contd)
• When servicing or performing maintenance on
  robotic equipment, always deenergize it before
  entering the area and performing any work.
• Never depend on the stoppage of the automatic
  shut off control circuit alone to cut all power
  to the robotic machine.

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Feeding and Ejection Methods

• Robotic Machines (contd)
• ALL employees must be clear from the danger area
  once maintenance has been completed.
• The danger zone is separated from the safe zone
  by light curtains and a safety barrier consisting
  of a Plexiglas wall that contains the robotic
  machinery.
• NEVER bypass safety switches, light curtains,
  emergency stop buttons, etc. when performing
  maintenance on robotic machinery or any other
  type of machinery.

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Lock out/tag out

• Lock out/tag out is also an integral part of
  workplace safety. When
• machine guarding must be removed for maintenance,
  proper lock
• out/tag out procedures must be followed.
• When performing maintenance do the following
• - Notify all affected employees that the
  machine or equipment
• must be shut down to perform
  maintenance or servicing.
• - Isolate the machine or piece of
  equipment from its energy source.
• - The energy source should be locked out
  or tagged out.
• - Any stored or residual energy should be
  relieved from the
• machine.
• - The machine or equipment should be
  verified that it is isolated
• from the energy source.

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Lock Out/Tag Out

• If you have any questions or concerns, contact
  your supervisor or UNC Environment, Health
  Safety for more specific LOTO procedures.
• Additional information concerning LOTO can be
  found on the UNC Environment, Health Safety
  website.
• Link http//www.ehs.unc.edu
• Link http//www.ehs.unc.edu/manuals/imac/
• Contact Info Kim Haley (843-2735

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Standard References

• Additional Information concerning Machine
  Guarding can be found under
• OSHA 1910.213 (Woodworking Machinery
  Requirements)
• Also addressed in UNC IMAC Manual Machine
  Guarding Policy.
• OSHA 1910.215 (Abrasive Wheel Machinery)
• Also addressed in UNC IMAC Manual Machine
  Guarding Policy as well as the Hand and Portable
  Power Tools Policy.
• OSHA 1910.217 (Mechanical Power Presses)
• OSHA 1910.217 App. A D (Non-mandatory and
  Mandatory Guidelines for Various
  Machines/Safeguards.)
• OSHA 1910.218 (Forging Machines)
• OSHA 1910.219 (Mechanical Power Transmission
  Apparatus)

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Summary

• Machine guarding is important for your personal
  health and safety and those that work around you.
  Before beginning daily work activities, assess
  all work areas where machinery is present and
  check for possible hazards/missing guards/etc.
  Make sure that all guards on equipment are
  adjusted and functioning properly. Guarding
  should never be removed except for maintenance
  procedures. If machine guarding is not in place
  do not use the equipment, and use proper
  procedures to ensure that guarding is put in
  place.
• If you have any questions or concerns about
  machine guarding contact your departmental
  supervisor or UNC Environment, Health, Safety
  at 962-5507.