Machine GuardingMODULE 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

1. Point of operation: where work is performed on the material, such as cutting, shaping, boring, or forming of stock.

2. 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

3. Operation Controls: Control mechanisms

4. 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 operator’s 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

Machinery and Machine Guarding29 CFR 1910 SUBPART O

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Organization

211.Definitions212.General requirements for all machines213.Woodworking machinery requirements215.Abrasive wheel machinery216.Mills and calenders in the rubber and

plastics industries217.Mechanical power presses218.Forging machines219.Mechanical power-transmission apparatus

General Requirements29 CFR 1910.212

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1910.212(a) Machine guarding

1. One or more types of guarding to protect from hazards.

Barrier guards Two-hand tripping devices Electronic safety devices Etc.

2. Affixed to machine where possible Guard must not cause its own hazard

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1910.212(a) Machine guarding

3. Point of operation guarding:ii. Guarded if exposes employee to injury

According to standards or Keep any part of body out of danger zone

iii. Hand tools to permit material handling – in addition to guards, not instead

iv. Examples of machines requiring guards on point of operation

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1910.212(a) Machine guarding

4. Revolving barrels, drums, containers guarded by interlocked enclosure (cannot turn without guard in place)

5. 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

Abrasive Wheel Machinery29 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 closelyadjusted

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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

Mechanical Power-Transmission Apparatus

29 CFR 1910.219

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Organization of 1910.219

(a) General requirements

(b) Prime-mover guards(1) Flywheels

(2) Cranks and connecting rods

(3) 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

Hazards on Oil and Gas SitesMachine 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

Safety ResponsibilitiesMachine 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

Hand and Portable Power Tools29 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 <30 p.s.i. Only with effective chip guarding and PPE

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1910.243(a) Portable powered tools

Portable circular saws >2 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

c. Portable abrasive wheels: Must be guarded Ring test and inspection

d. Explosive actuated fastening toolse. Power lawnmowers

Guarding Controls and shutoff device Labeling, manuals Design

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1910.244 Other portable tools and equipment

a. Jacks Loading and marking Operation and maintenance

b. 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