MSHA

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MSHAS Guide to Equipment Guarding
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Advantages of Using Expanded Metal or Sizing
Screen

• The components guarded can be inspected without
  removing the guard.
• Grease fittings and oil cups can be placed
  through the openings without cutting large holes
  in the guard.

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Advantages of Using Expanded Metal or Sizing
Screen

• At most operations this material is readily
  available.
• In certain circumstances, the use of expanded
  metal guards serves to allow smaller particles of
  spilled material to pass through the guard with
  minimal buildups.

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Equipment Guarding

• This presentation contains examples of commonly
  used equipment guards.
• Alternative designs are acceptable provided the
  requirements of the guarding standards are met.
• MSHA recognizes that there may be site specific
  complex situations which require unique guard
  design and installation.

5
MSHA Requirements

• Moving machine parts must be guarded to protect
  persons from contacting gears, sprockets, chains,
  drive, head, tail and takeup pulleys, flywheels,
  couplings, shafts, fan blades, saw blades, and
  similar moving parts that can cause injury.

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MSHA Requirements

• Overhead drive belts must be guarded where the
  whipping action of a broken belt could be
  hazardous to persons.

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MSHA Requirements

• Unguarded conveyors next to travelways must be
  equipped with emergency stop devices to readily
  deactivate the drive motor.

8
Designing Guards

• Consider all possible contingencies , including
  acts of thoughtlessness and foolhardiness.
• The opinions of the operator of the machine, the
  supervisors, and maintenance personnel could
  enhance design and construction.
• Guards cannot be removed unless the hazards they
  guard against have been eliminated.

9
Effective Characteristics

• Considered a permanent part of the machine or
  equipment.
• Installed as close to the machine part as
  feasibly possible.
• Prevent access to all moving machine parts.
• Designed for the specific job and specific
  machine.

10
Effective Characteristics

• Designed and fabricated to the extent practical
  to such dimensions and weights that one person
  is able to physically install and remove the
  individual guard components.
• Constructed and maintained to withstand vibration
  and shock during normal operation.
• Not present a hazard in itself.

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Equipment Guarding

• Materials for guards should be carefully
  selected. For most installations, guards
  constructed of metal framing with sheet metal,
  perforated metal, expanded metal, or heavy wire
  mesh are more satisfactory than those of other
  materials.

12
Methods of Guarding

• The selection of a guarding method may depend
  upon a number of factors such as
• space limitations,
• production methods, and
• frequency of use.

13
Methods of Guarding

• Moving machine parts must be guarded rather than
  restricting access to the area by installing
  railings, chains, cable, or gates.

14
Area Guards

• An area guard is any guard which covers more
  than one independently controlled component, or
• is large enough to permit a person to place
  themselves between the moving machine parts and
  the guard.
• Area guarding is not acceptable!

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Examples of Area Guards

• Gates, doors, or barriers constructed across
  openings into areas that contain multiple tail
  pulleys, drive belts, drive pulleys, and other
  moving machine parts.
• Fencing constructed around areas that contain
  more than one independently controlled pulley,
  shaft, or drive belt.

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Examples of Area Guards

• A guard that can be entered by persons enabling
  them to get between the inner perimeter of the
  guard and the moving machine parts.
• Historically, if space is provided between a
  guard and a hazard, someone will eventually go
  there and be exposed to the hazard.

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