Subpart O Machine Guarding

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Subpart O - Machine Guarding

• OTI 501
• Paul Schlumper

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We Will Cover

• Machine Guarding Principles
• Subpart O - Highlights
• Mock Plant Walk-Through

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Why are machines not guarded?

• No one would stick their arm, hand, finger, head,
  etc. in there.
• No one is supposed to be back there, in there,
  around it while it is running.
• The machine came that way it never had a guard.
• Ive been doing it this way for twenty years
  without any problems.

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Why are machines not guarded? (cont.)

• The guard is in the way
• The OSHA inspector didnt say anything about it.
• Well put it back on if OSHA comes.

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Emphasis on Amputations Where does it apply?

• General industry employers whose workplaces
  include
• shears
• saws
• slicers
• slitters
• power presses
• (the 4s and a P)

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Requirements for Safeguards

• Prevent contact - prevent workers body or
  clothing from contacting hazardous moving parts
• Secure - firmly secured to machine and not easily
  removed
• Protect from falling objects - ensure that no
  objects can fall into moving parts
• Create no new hazards - must not have shear
  points, jagged edges or unfinished surfaces
• Create no interference - must not prevent worker
  from performing the job quickly and comfortably
• Allow safe lubrication - if possible, be able to
  lubricate the machine without removing the
  safeguards

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Where machine hazards occur

• Point of operation
• Mechanical power transmission
• Other moving parts

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Machine Hazards
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Machine Guarding
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In-Running Nip Points
Rotating cylinders
Belt and pulley
Chain and sprocket
Rack and pinion
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Methods of machine safeguarding

• Physical guards
• Devices
• Location/Distance

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Methods of Machine Safeguarding

• Guards
• fixed
• interlocked
• adjustable
• self-adjusting
• Devices
• presence sensing
• pullback
• restraint
• safety controls (tripwire cable, two-hand contol,
  etc.)
• gates

• Location/distance
• Feeding and ejection methods
• automatic and/or semi-automatic feed and ejection
• robots
• Miscellaneous aids
• awareness barriers
• protective shields
• hand-feeding tools

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Guards

• Fixed
• Interlocked
• Adjustable
• Self-adjusting

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Fixed Guard
Provides a barrier - a permanent part of the
machine, preferable to all other types of guards.
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Interlocked Guard
When this type of guard is opened or removed, the
tripping mechanism and/or power automatically
shuts off or disengages, and the machine cannot
cycle or be started until the guard is back in
place.
Interlocked guard on revolving drum
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Adjustable Guard
Provides a barrier which may be adjusted to
facilitate a variety of production operations.
Bandsaw blade adjustable guard
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Self-Adjusting Guard
Provides a barrier which moves according to the
size of the stock entering the danger area.
Circular table saw self-adjusting guard
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Safeguarding devices

• Presence sensing
• Pullback
• Restraint
• Safety controls and trips
• Gates

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Pullback Device

• Utilizes a series of cables attached to the
  operators hands, wrists, and/or arms
• Primarily used on machines with stroking action
• Allows access to the point of operation when the
  slide/ram is up
• Withdraws hands when the slide/ram begins to
  descend

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Pullback Device (contd)

• Hands in die, feeding
• Point of operation exposed
• Pullback device attached and properly adjusted

• Die closed
• Hands withdrawn from point of operation by
  pullback device

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Restraint Device

• Uses cables or straps attached to the operators
  hands and a fixed point
• Must be adjusted to let the operators hands
  travel within a predetermined safe area
• Hand-feeding tools are often necessary if the
  operation involves placing material into the
  danger area

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Safety Tripwire Cables

• Device located around the perimeter of or near
  the danger area
• Operator must be able to reach the cable to stop
  the machine

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Two-Hand Control

• Requires constant, concurrent pressure to
  activate the machine
• The operators hands are required to be at a safe
  location (on control buttons) and at a safe
  distance from the danger area while the machine
  completes its closing cycle

.
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Gate

• Movable barrier device which protects the
  operator at the point of operation before the
  machine cycle can be started
• If the gate does not fully close, machine will
  not function

Gate Open
Gate Closed
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Safeguarding by Location/Distance

• Locate the machine or its dangerous moving parts
  so that they are not accessible or do not present
  a hazard to a worker during normal operation
• Maintain a safe distance from the danger area

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Automatic Feed(shown on power press)
Transparent Enclosure Guard
Stock Feed Roll
Danger Area
Completed Work
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Robots

• Machines that load and unload stock, assemble
  parts, transfer objects, or perform other tasks
• Best used in high-production processes requiring
  repeated routines where they prevent other
  hazards to employees

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Protective Shields
These do not give complete protection from
machine hazards, but do provide some protection
from flying particles, splashing cutting oils, or
coolants.
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Holding Tools

• Used to place and remove stock in the danger area
• Not to be used instead of other machine
  safeguards, but as a supplement

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Subpart O - Machinery and Machine Guarding

• 211 - Definitions
• 212 - General requirements
• 213 - Woodworking machinery
• 215 - Abrasive wheel machinery
• 216 - Mills and calendars
• 217 - Mechanical power presses
• 218 - Forging machines
• 219 - Mechanical power transmission

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1910.212

• General Requirements for all Machines

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1910.212(a)(1)

• One or more methods of machine guarding shall be
  provided to protect the operator and other
  employees in the machine area from hazards such
  as those created by the point of operation,
  in-going nip points, rotating parts, flying chips
  and sparks.

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1910.212(a)(3)(ii)

• The point of operation of machines whose
  operation exposes an employee to injury, shall be
  guarded

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1910.212(a)(5)

• When the periphery of the blades of a fan is less
  than seven (7) feet above the floor or working
  level, the blades shall be guarded. The guard
  shall have openings no larger than 1/2 inch.

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1910.212(b)

• Machines designed for a fixed location shall be
  securely anchored to prevent walking or moving.

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1910.213

• Woodworking Machinery Requirements

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1910.213(a)(9)

• All belts, pulleys, gears, shafts, and moving
  parts shall be guarded in accordance with the
  specific requirements of 1910.219.

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1910.213(b)(1)

• A mechanical or electrical power control shall be
  provided on each machine to make it possible for
  the operator to cut off the power from each
  machine without leaving his position at the point
  of operation.

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1910.213(b)(3)

• On applications where injury to the operator
  might result if motors were to restart after
  power failures, provision shall be made to
  prevent machines from automatically restarting
  upon restoration of power.

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Table Saws
46
1910.213(c)(1)

• Each circular hand-fed ripsaw shall be guarded by
  a hood which shall completely enclose that
  portion of the saw above the table and that
  portion of the saw above the material being cut.
  The hood and mounting shall be arranged so that
  the hood will automatically adjust itself to the
  thickness of and remain in contact with the
  material being cut without considerable
  resistance.

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1910.213(c)(2)

• Each hand-fed circular ripsaw shall be furnished
  with a spreader to prevent material from
  squeezing the saw or being thrown back on the
  operator.

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1910.213(c)(3)

• Each hand-fed circular ripsaw shall be provided
  with non-kickback fingers or dogs so located as
  to oppose the thrust or tendency of the saw to
  pick up the material or throw it back toward the
  operator.

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1910.213(d)(1)

• Each circular crosscut table saw shall be guarded
  by a hood which shall meet all the requirements
  of 1910.213(c)(1) for hoods for circular resaws.

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Radial Arm Saws
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1910.213(i)(1)

• All portions of the saw blade (bandsaws) shall be
  enclosed or guarded, except for the working
  portion of the blade between the bottom of the
  guide rolls and the table.

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1910.213(r)(4)

• The mention of specific machines in paragraphs
  (a) thru (q) and this paragraph (r) of this
  section, inclusive, is not intended to exclude
  other woodworking machines from the requirements
  that suitable guards and exhaust hoods be
  provided to reduce to a minimum the hazard due to
  the point of operation of such machines.

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1910.213(s)(7)

• All cracked saws shall be removed from service.

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1910.215

• Abrasive-Wheel Machinery

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1910.215(a)(4)

• Work rests shall be adjusted closely to the wheel
  with a maximum opening of one-eighth inch to
  prevent the work from being jammed between the
  wheel and the rest, which may cause wheel
  breakage.

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1910.215(b)(9)

• The distance between the wheel periphery and the
  adjustable tongue or the end of the peripheral
  member at the top shall never exceed one-fourth
  inch.

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1910.215(d)(1)

• Immediately before mounting, all wheels shall be
  closely inspected and sounded by the user (ring
  test) to make sure they have not been damaged.

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Abrasive Wheel Machinery
The distance between the wheel periphery and the
adjustable tongue must never exceed 1/4-inch.
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1910.217

• Mechanical Power Presses

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1910.217(a)(5)

• Press brakes, hydraulic and pneumatic power
  presses, bulldozers, hot bending and hot metal
  presses, forging presses and hammers, riveting
  machines and similar types of fastener
  applicators are excluded from the requirements of
  this section.

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1910.217(b)(4)

• The pedal mechanism shall be protected to prevent
  unintended operation.
• A pad with a nonslip contact area shall be firmly
  attached to the pedal.

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1910.217(b)(6)

• A two-hand trip shall have the individual
  operators hand controls protected against
  unintended operation and be arranged to require
  use of both hands.
• Two-hand trip systems on full revolution clutch
  machines shall incorporate an antirepeat feature.
• If two hand trip systems are used on multiple
  operator systems, each operator shall have a
  separate set of controls.

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1910.217(b)(7)

• Two-hand controls must incorporate an anti repeat
  feature, require use of both hands, be protected
  against unintended operation, have one set of
  controls for each operator.
• If foot control is provided, the selection
  between hand and foot control must be supervised
  by the employer.

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1910.217(c)(1)

• It shall be the responsibility of the employer to
  provide and insure the use of point of operation
  guards or properly applied and adjusted point of
  operation devices on every operation performed on
  a mechanical power press. See Table O-10.

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1910.217(e)(1)

• It shall be the responsibility of the employer to
  establish and follow a program of periodic and
  regular inspections of power presses.

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1910.217(e)(3)

• It shall be the responsibility of the employer to
  insure the original and continuing competence of
  personnel caring for, inspecting, and maintaining
  power presses.

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1910.219

• Mechanical Power-Transmission Apparatus

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1910.219(b)(1)

• Flywheels located so that any part is 7 feet or
  less above the floor or platform shall be
  guarded.
• Wherever flywheels are above working areas,
  guards shall be installed having sufficient
  strength to hold the weight of the flywheel in
  the event of a shaft or wheel mounting failure.

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1910.219(c)

• Horizontal, vertical, and inclined shafting must
  be enclosed.
• Projecting shaft ends shall present a smooth edge
  and end and shall not project more than 1/2 the
  diameter of the shaft unless guarded by non
  rotating cap or safety sleeves.

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1910.219(d)

• Pulleys 7ft. or less above the floor or platform
  must be guarded.
• Pulleys with cracks or pieces broken out of rims
  shall not be used.

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Portable Power Tools - General Safety Precautions

• 1910.242(a)
• Employers responsibility
• Safe condition of tools
• Including personal tools
• 1910.242(b)
• Compressed air not used for cleaning except where
  reduced to less than 30 p.s.i. and only when
  effective chip guarding and PPE.

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Power Tools

• Classification by power source
• Electric
• Pneumatic
• Liquid Fuel
• Hydraulic
• Powder Actuated

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Power Tools (cont.)

• 1910.243 (a)(1) Portable Circular Saws
• Upper blade guard
• Lower blade guard
• Automatically returns to starting position

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Power Tools (cont.)

• 1910.243(a)(2)
• Constant Pressure Switch
• Saws and Chainsaws
• Lock-on control (single motion turnoff)

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Pneumatic Power Tools and Hose

• 1910.243(b)
• Tool Retainer A tool retainer must be installed
  on each piece of equipment where ejection could
  result
• Airhose Hose and hose connections must be
  designed for the pressure and service to which
  they are subjected

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Explosive Actuated Fastening Tools

• 1910.243(d)
• Must meet requirements in ANSI A10.3-1970
• Operators and assistants must wear eye protection
• Head and face protection dependent on working
  conditions

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Explosive Actuated Tools (Cont.)

• Muzzle must have protective shield or guard at
  least 3 ½ inches in diameter.
• Firing must be dependent on at least 2 separate
  and distinct operations.
• Firing mechanism must prevent tool from firing
  during loading, while preparing, if dropped.

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Explosive Actuated Tools (Cont.)

• Tools must not be loaded until just before
  intended firing.
• Do not point at anyone!
• Fasteners not driven into hard/brittle or easily
  penetrable material
• Tools not used in hazardous atmosphere

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Lawnmowers

• 243(e)
• Meet the requirements of ANSI B71.1-X1968