Machine Guarding MODULE 19 https://www.osha.gov/dte/grant_materials/fy06/46f6.../19_machine_guarding2.ppt

What hazards exist? Crushed by or drawn into equipment Struck by moving parts Struck by failed components or particles

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.

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

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

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

In-Running Nip Points Between 2 rotating parts Between rotating and tangential parts Between rotating and fixed parts which shear, crush, or abrade

Reciprocating Parts Risk of being struck between stationary and moving part

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

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

Punching action Ram stamps materials Danger at point of operation

Shearing action Powered blade that shears materials Hazard at point of operation

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

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

Guarding Methods Location / distance Guards Fixed Interlocked Adjustable Self-adjusting

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

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

Fixed Guard Barrier is a permanent part of machine Preferable over other types

Interlocked Guard Stops motion when guard is opened or removed Interlocked guard on revolving drum

Adjustable Guard Barrier may be adjusted for variable operations What are the drawbacks? Bandsaw blade adjustable guard

Self-Adjusting Guard Adjusts according to size/position of material Circular table saw self-adjusting guard

Pullback Device Cables attached to operator’s hands or wrists Removes hands from point of operation during danger period What are the drawbacks?

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

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

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

Gate Must close fully to protect user before cycle will start Gate Open Gate Closed

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

Protective Shields Protection from flying particles or splashing fluids Do not protect completely from machine hazards

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 Guarding 29 CFR 1910 SUBPART O

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

General Requirements 29 CFR 1910.212

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

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

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

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 Machinery 29 CFR 1910.215

1910.215(a) General requirements Abrasive wheels must be guarded, with exceptions Guard design dependent on type of work and type of wheel

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

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

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

Ring Test

Mechanical Power-Transmission Apparatus 29 CFR 1910.219 Mechanical Power-Transmission Apparatus

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

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

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

Safety Responsibilities Machine Guarding

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

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 Tools 29 CFR 1910 Subpart P and 1926 Subpart I

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

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

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

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

1910.243(b) Pneumatic powered tools and hose Tool retainer to prevent ejection Airhose designed for applied pressure and service

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

1910.244 Other portable tools and equipment Jacks Loading and marking Operation and maintenance Abrasive blast cleaning nozzles: operating valve and support

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

1926.300 General requirements Abrasive wheel guards PPE if necessary for objects, particles, gases Allowable switches by tool type

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

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

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

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