Machine Guarding

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Machine Guarding

• MODULE 19

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What hazards exist?

• Crushed by or drawn into equipment
• Struck by moving parts
• Struck by failed components or particles

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Key parts of machines

• Point of operation where work is performed on
  the material, such as cutting, shaping, boring,
  or forming of stock.
• Power Transmission Device transmits energy to
  the part of the machine performing the work
• Includes flywheels, pulleys, belts, connecting
  rods, couplings, cams, spindles, chains, cranks,
  and gears.

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Key parts of machines

• Operation Controls Control mechanisms
• Other moving parts can include reciprocating,
  rotating, and transverse moving parts, feed
  mechanisms, and auxiliary parts of the machine

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Hazards to be Guarded

• Things to guard include
• In-running nip points
• Rotating equipment
• Flying chips or sparks
• Belts or gears
• Parts that impact or shear

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Rotating Parts

• Can grip hair or clothing
• Can force the body into a dangerous position
• Projecting pieces increase risk

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In-Running Nip Points

• Between 2 rotating parts
• Between rotating and tangential parts
• Between rotating and fixed parts which shear,
  crush, or abrade

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Reciprocating Parts

• Risk of being struck between stationary and
  moving part

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Transverse motion

• Continuous straight line motion
• Worker struck or caught in pinch or shear point

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Cutting action

• Direct injury from cutting action
• Flying chips or sparks
• Saws, drills, lathes, mills

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Punching action

• Ram stamps materials
• Danger at point of operation

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Shearing action

• Powered blade that shears materials
• Hazard at point of operation

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Bending action

• Power applied to a slide to stamp/shape materials
• Hazard at point of operation

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Guarding Principles

• Prevent contact between hazardous moving parts
  and body or clothing
• Secure guard not easily removed
• Protect from objects falling into machinery
• No new hazards sharp/rough edges
• No interference with job/comfort/speed
• Allow safe lubrication without removing guards
  if possible

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Guarding Methods

• Location / distance
• Guards
• Fixed
• Interlocked
• Adjustable
• Self-adjusting

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Guarding Methods

• Devices
• Presence sensing
• Pullback
• Restraint
• Safety controls (tripwire cable, two-hand
  control, etc.)
• Gates

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Guarding Methods

• Feeding ejection methods
• Automatic and/or semi-automatic feed and ejection
• Robots
• Miscellaneous aids
• Awareness barriers
• Protective shields
• Hand-feeding tools

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Fixed Guard

• Barrier is a permanent part of machine
• Preferable over other types

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Interlocked Guard

• Stops motion when guard is opened or removed

Interlocked guard on revolving drum
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Adjustable Guard

• Barrier may be adjusted for variable operations
• What are the drawbacks?

Bandsaw blade adjustable guard
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Self-Adjusting Guard

• Adjusts according to size/position of material

Circular table saw self-adjusting guard
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Pullback Device

• Cables attached to operators hands or wrists
• Removes hands from point of operation during
  danger period
• What are the drawbacks?

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Restraint Device

• Cables attached to fixed point and wrists or
  hands
• Adjustable to let hands travel in predetermined
  area
• May be accompanied by hand-feeding tools

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Safety Tripwire Cable

• 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 pressure on both pads to
  activate the machine
• Hands on controls at safe distance while machine
  is in dangerous cycle

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Gate

• Must close fully to protect user before cycle
  will start

Gate Open
Gate Closed
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Safeguarding by Location/Distance

• Location of hazardous parts that is inaccessible
  or not a hazard during normal operation
• Must maintain safe distance
• Training, warning, communication necessary

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Protective Shields

• Protection from flying particles or splashing
  fluids
• Do not protectcompletely frommachine hazards

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What regulations apply?

• 29 CFR 1910 Subpart O
• 29 CFR 1910 Subpart P for hand and portable power
  tools
• API RP 54 6.8 Machinery and Tools

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Machinery and Machine Guarding

• 29 CFR 1910 SUBPART O

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Organization

• Definitions
• General requirements for all machines
• Woodworking machinery requirements
• Abrasive wheel machinery
• Mills and calenders in the rubber and plastics
  industries
• Mechanical power presses
• Forging machines
• Mechanical power-transmission apparatus

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General Requirements

• 29 CFR 1910.212

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1910.212(a) Machine guarding

• One or more types of guarding to protect from
  hazards.
• Barrier guards
• Two-hand tripping devices
• Electronic safety devices
• Etc.
• Affixed to machine where possible
• Guard must not cause its own hazard

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1910.212(a) Machine guarding

• Point of operation guarding
• Guarded if exposes employee to injury
• According to standards or
• Keep any part of body out of danger zone
• Hand tools to permit material handling in
  addition to guards, not instead
• Examples of machines requiring guards on point of
  operation

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1910.212(a) Machine guarding

• Revolving barrels, drums, containers guarded by
  interlocked enclosure (cannot turn without guard
  in place)
• Exposure to fan blades guard openings ?1/2 inch

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1910.212(b) Anchoring fixed machinery

• Machines designed for fixed location must be
  anchored to prevent moving

This pedestal grinder is designed for anchoring,
but is not anchored
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Abrasive Wheel Machinery

• 29 CFR 1910.215

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1910.215(a) General requirements

• Abrasive wheels must be guarded, with exceptions
• Guard design dependent on type of work and type
  of wheel

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1910.215(a) General requirements

• Work rests
• Rigid, clamped in place securely
• Adjusted to within 1/8 inch of wheel
• Never adjusted while in motion

Work rest is closely adjusted
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1910.215(b)(9) Exposure adjustment

• For type where operator stands in front of
  opening Adjustable for decreasing wheel size
• Adjustable tongue guard must never be more than ¼
  inch from wheel

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1910.215(d) Mounting

• Inspect for damage and ring test immediately
  before mounting
• Tap with light nonmetallic implement
  (screwdriver, wooden mallet)
• If sound is dead, cracked ring may not be used
• Check spindle speed against maximum for wheel

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Ring Test
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Mechanical Power-Transmission Apparatus

• 29 CFR 1910.219

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Organization of 1910.219

• (a) General requirements
• (b) Prime-mover guards
• Flywheels
• Cranks and connecting rods
• Tail rods or extension piston rods
• (c) Shafting
• (d) Pulleys

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Organization of 1910.219

• (e) Belt, rope, and chain drives
• (f) Gears, sprockets, and chains
• (g) Guarding friction drives
• (h) Keys, setscrews, and other projections
• (i) Collars and couplings
• (j) Bearings and facilities for oiling
• (k) Guarding of clutches, cutoff couplings, and
  clutch pulleys

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Organization of 1910.219

• (l) Belt shifters, clutches, shippers, poles,
  perches, and fasteners
• (m) Standard guards-general requirements
• (o) Approved materials
• (p) Care of equipment

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Hazards on Oil and Gas Sites

• Machine Guarding

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Parts Requiring Guarding

• Drive belts and shafts mud pumps and tank area
• Pony rods
• Rotating parts
• Shale shaker
• Agitator shafts couplings
• Moving generator parts
• (explore)

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Mud Pumps
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Shale Shaker
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Generators
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Parts Requiring Guarding

• Air compressors
• Crown sheaves
• Kelly bushing or controls
• Rotary chain drive
• Air hoist line
• Drawworks
• Bench grinder wheels

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Crown Sheaves
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Kelly and Bushing

• Alternative Abatement STD 1-12.28 CH-1

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Drawworks
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Parts Requiring Guarding

• Belts, drive chains, gears and drives on power
  and hand tools
• Traveling blocks
• Sheaves
• Cathead?

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Drilling Line
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Traveling Block
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Hoisting Line
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Safety Responsibilities

• Machine Guarding

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Safety Responsibilities

• Management
• Ensure all machinery is properly guarded
• Supervisors
• Train employees on specific guard rules in their
  areas
• Ensure machine guards remain in place and are
  functional
• Immediately correct machine guard deficiencies
• Employees
• Do not remove guards unless machine is locked and
  tagged
• Report machine guard problems to supervisors
  immediately
• Do not operate equipment unless guards are in
  place

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Training

• Operators/affected employees should receive
  training on
• Hazards associated with particular machines
• How the safeguards provide protection and the
  hazards for which they are intended
• How and why to use the safeguards
• How and when safeguards can be removed and by
  whom
• What to do if a safeguard is damaged, missing, or
  unable to provide adequate protection

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Hand and Portable Power Tools

• 29 CFR 1910 Subpart P and 1926 Subpart I

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Construction vs. General Industry

• Construction, alteration, or repair?
• Applicable standard depends on type of
  operations
• 1910 Subpart P Hand and Portable Powered Tools
  and Other Hand-Held Equipment
• 1926 Subpart I Tools Hand and Power

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1910.242 General

• Employer is responsible for safe condition of
  tools and equipment
• Including equipment furnished by employee
• Compressed air must not be used for cleaning
  unless
• Reduced to lt30 p.s.i.
• Only with effective chip guarding and PPE

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1910.243(a) Portable powered tools

• Portable circular saws gt2 in. guarded
• Automatic return to covering position
• Switches and controls
• constant pressure control for circular and chain
  saws
• other controls for other tools as appropriate

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1910.243(a) Portable powered tools

• Portable belt sanding machine guarding
• Nip points
• Unused run of sanding belt
• Cracked saws remove from service
• Grounding Meet Subpart S

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1910.243(b) Pneumatic powered tools and hose

• Tool retainer to prevent ejection
• Airhose designed for applied pressure and service

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1910.243 Guarding of portable powered tools

• Portable abrasive wheels
• Must be guarded
• Ring test and inspection
• Explosive actuated fastening tools
• Power lawnmowers
• Guarding
• Controls and shutoff device
• Labeling, manuals
• Design

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1910.244 Other portable tools and equipment

• Jacks
• Loading and marking
• Operation and maintenance
• Abrasive blast cleaning nozzles operating valve
  and support

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1926.300 General requirements

• Maintained in safe condition whether furnished by
  employer or employee
• Shall be guarded when designed to accommodate
  guards
• Moving parts that create hazards shall be guarded
  by one or more methods
• Fan openings anchoring machinery

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1926.300 General requirements

• Abrasive wheel guards
• PPE if necessary for objects, particles, gases
• Allowable switches by tool type

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1926.301 Hand tools

• Use of unsafe hand tools not permitted
• Wrenches shall not be used when jaws are sprung
  to the point of slippage
• Including adjustable, pipe, end socket wrenches
• Impact tools shall be kept free of mushroomed
  heads
• Such as drift pins, wedges chisels
• Wooden handles shall be kept
• Free of splinters or cracks
• Tight in the tool

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1926.302 Power-operated hand tools

• Electric power-operated tools
• Double-insulated or grounded
• Never hold by the cord
• Pneumatic power-operated tools
• Secure tools, attachments, and muzzle
• Compressed air use restrictions
• Never hold by the hose
• Reduce pressure in case of hose failure

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1926.302 Power-operated hand tools

• Fuel operated tools
• Stop while refueling or servicing
• Watch concentrations in enclosed spaces
• Hydraulic power tools
• Fire-resistant fluids
• Safe operating pressures
• Powder-actuated tools

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1926 Subpart I Organization

• 1926.303 Abrasive wheels and tools
• 1926.304 Woodworking tools
• 1926.305 Jacks
• 1926.306 Air receivers
• 1926.307 Mechanical power-transmission apparatus