Machine Safeguarding

Chapter 39Machine SafeguardingChapter Outline1Overview 21.1Hazards/Impacts 2 2Scope 22.1Exemptions 2 3Standards 3 4Definitions 3 5Requirements 45.1General 45.1.1Safeguards 45.1.2Authorization 55.1.3Roles and Responsibilities 55.2Procedures and Specific Requirements 65.2.1Machine Safeguarding Evaluation and Design 75.2.2General Safeguarding Methods and Options 75.2.3Equipment-specific Techniques 75.2.4Equipment Maintenance 75.2.5Other Requirements 85.3Training 95.3.1Required 95.3.2On-the-Job Training 95.3.3Recommended Training 10 6Exhibits 10 7References 11 8Ownership 12SLAC Environment, Safety, and Health Manual Chapter 39: Machine Safeguarding 1OverviewThe federal Occupational Safety and Health Administration (OSHA) requires that machine guarding andother safeguards be provided and maintained in a manner sufficient to protect machine operators and other persons present in machine areas from hazards associated with the operation of machines. The purpose of the machine safeguarding program at SLAC is to provide minimum safety requirements for areas wheremachining tools are used and to assist machine operators, custodians, and supervisors in carrying out their responsibilities for ensuring machine safety through hazard identification and evaluation, safeguarding,training, and safe operation.1.1Hazards/ImpactsHazards include those created by points of operation, in-going nip points, rotating parts, flying chips,sparks, moving belts, meshing gears, cutting teeth, or by any parts that impact or shear or havereciprocating, transverse, cutting, punching, shearing, boring, or bending actions.A partial list of possible machinery-related injuries includes crushed hands and arms, severed fingers, skinlacerations, scalping, hot metal burns, eye injuries, and blindness.2ScopeThe requirements of this chapter apply to machine tools, mechanical equipment, and any areas of SLACwhere machining or working on metal, plastic, or wood occurs. (For a list of machine shops, see Section 6, “Exhibits”, Machine Shops.)Note The scope of this chapter is not limited to machine shops, but extends to all machine tools and the locations where they are used.The requirements of this chapter apply to all personnel who operate machine tools, including SLACemployees, users, students, and subcontractors.2.1ExemptionsThe use of powered and non-powered portable hand-held tools (such as sanders, drills, sawzalls, stapleguns, impact wrenches, powder actuated tools, screw drivers, wrenches, files, hammers, scissors, etc.) isnot addressed in this chapter. Refer to ES&H Manual, Chapter 25, “Tools – Power and Hand Operated”.11 SLAC Environment, Safety, and Health Manual (SLAC-I-720-0A29Z-001), Chapter 25, “Tools –Power and Hand Operated”, http://www-/esh/hazardous_activities/tools_powerhand/policies.htmChapter 39: Machine Safeguarding SLAC Environment, Safety, and Health Manual 3StandardsSLAC adheres to the following standards for machine safeguarding:Title 29, Code of Federal Regulations, Part 1910, Subpart O, “Machinery and Machine Guarding”2–Part 1910.211, “Machinery and Machine Guarding – Definitions” (29 CFR 1910.211)–Part 1910.212, “General Requirements for All Machines“ (29 CFR 1910.212)–Part 1910.213, “Woodworking Machinery Requirements“ (29 CFR 1910.213)–Part 1910.215, “Abrasive Wheel Machinery“ (29 CFR 1910.215)–Part 1910.217, “Mechanical Power Presses“ (29 CFR 1910.217)–Part 1910.219, “Mechanical Power-Transmission Apparatus“ (29 CFR 1910.219) Title 29, Code of Federal Regulations, Part 1926, Subpart I, “Tools – Hand and Power”3–Part 1926.300, “Hand and Power Tools General Requirements“ (29 CFR 1926.300)–Part 1926.303, “Abrasive Wheels and Tools“ (29 CFR 1926.303)–Part 1926.304, “Woodworking Tools“ (29 CFR 1926.304)–Part 1926.307, “Mechanical Power-Transmission Apparatus“ (29 CFR 1926.307) National Fire Protection Association (NFPA) 79-2002, “Electrical Standard for Industrial Machinery”44DefinitionsCustodian (machine). A person who is responsible for a machine or piece of equipment, and who ensures that it is safely operated and properly maintained. May include machine shop supervisors.Danger zone. Any place in or about a machine or piece of equipment where a person may be struck by or caught between moving parts, caught between moving and stationary objects or parts of the machine,caught between the material and a moving part of the machine, burned by hot surfaces or exposed toelectric shockGuard. A barrier that prevents entry of the operator's hands or fingers into the point of operation, pinch or nip point, or moving parts. Can be fixed, interlocked, adjustable, or self-adjusting.Guarded. Shielded, fenced, enclosed or otherwise protected by means of suitable enclosure guards, covers or casing guards, trough or “U” guards, shield guards, standard railings or by the nature of the location, so as to remove the hazard of accidental contact2 /pls/oshaweb/owadisp.show_document?p_table=STANDARDS&p_id=101313 /pls/oshaweb/owadisp.show_document?p_table=STANDARDS&p_id=109134 See the SLAC Library, /library/, for available standards. NFPA standardsare available online from a SLAC login (see /library/eresources/slac.htmfor the link and instructions); some hard copies are also available.SLAC Environment, Safety, and Health Manual Chapter 39: Machine Safeguarding Interlock. A device that operates to prevent the operation of a machine while the cover or door of themachine is open or unlocked, and which will also hold the cover or door closed and locked while themachine is in motionMachine custodian. See custodian, machineMachine shop. An area where multiple types of machine tools may be used, generally in one designatedlocation within a building. May be under the supervision of a machine shop supervisor. May havededicated staff or walk-in users. A carpentry shop is included in this definition.Machine tool. Machining equipment that cuts, shears, punches, presses, drills, rolls, grinds, sands, or forms metal, plastic, or wood stock. Not included in this definition are hand-held, portable power, or manualtools.Mechanical power transmission apparatus. Mechanical component or prime mover that transfers power toa machine tool. May include shafting, flywheels, pulleys, belts, couplings, chain drives, cranks, gears.Pinch point. Any point other than the point of operation at which it is possible for a part of the body to be caught between moving parts, between moving and stationary parts, or between the material and movingparts of a machine toolPoint of operation. The point(s) where material is positioned, inserted, or manipulated, or where work such as shearing, punching, shaping, cutting, boring, forming, or assembling is being performed on the stockPositive disconnecting means. A device, or group of devices, or other means by which the conductors of a circuit can be physically disconnected from their source of supplyPrime mover. An engine or motor the main function of which is to drive or operate other mechanicalequipmentSee Section 6, “Exhibits”, Machine Safeguarding Terms, for additional definitions.5Requirements5.1General5.1.1SafeguardsSafeguards must be provided at three basic locations:1.At the point of operation2.At mechanical power transmission apparatus3.At other moving parts which could potentially create a hazardMachinery containing moving parts with rotating, transverse, or reciprocating action will be effectivelyguarded according to OSHA regulations. One or more methods of machine safeguarding must be providedChapter 39: Machine Safeguarding SLAC Environment, Safety, and Health Manual to protect from hazards such as those created by point of operation, nip points, rotating parts, flying chips, sparks and so on. Safeguards must conform to OSHA standards and are recommended to be designed inconformance with the American National Standards Institute (ANSI) B11 standard series (see Section 7,“References”).Neither OSHA nor ANSI standards offer guarding requirements for every possible machine configuration;therefore each machine must be evaluated by a knowledgeable, trained person and compared to theappropriate machine safeguarding standard. (See Section 6, “Exhibits”, for general recommendations onensuring the safety of the operator and other employees.)Note OSHA does not grant a grandfather clause for old equipment. All equipment must be safeguarded.Equipment must also be installed in conformance to applicable facility standards, such aselectrical and seismic.5.1.2AuthorizationNo person will operate machine tools without proper authorization from their supervisor and the machine custodian.5.1.3Roles and Responsibilities5.1.3.1Machine Safeguarding Program ManagerThe machine safeguarding program manager will, when requested by environment, safety, and health(ES&H) coordinators, machine operators, or machine custodians, assist in the interpretation of standards in support of compliance and safety improvement efforts and identify and develop appropriate training.5.1.3.2Managers and SupervisorsManagers and supervisors of personnel who operate machine tools willAuthorize personnel to use only the machine tools that they are qualified to operateProvide personal protective equipment (PPE) as needed to employeesExercise disciplinary action or restrict access to machines when personnel fail to follow safety requirements5.1.3.3Building, Area, and Facility ManagersBuilding, area, and facility managers willEnsure machines and moving parts of mechanical equipment within their facility are properly safeguarded5.1.3.4Conventional and Experimental Facilities DepartmentThe Conventional and Experimental Facilities (CEF) Department willEnsure moving parts of mechanical equipment that is part of the conventional facility (HVAC, pumps) are properly safeguardedSLAC Environment, Safety, and Health Manual Chapter 39: Machine Safeguarding5.1.3.5Machine CustodiansMachine custodians willEnsure machines are properly safeguarded, guards remain in place and are functional by conducting thorough, machine-specific safeguarding evaluations, either through knowledgeable internal SLACpersonnel or a qualified third partyEnsure machine tool users are trained, qualified, and competent in the proper and safe operation of machine tools before authorizing machine accessCommunicate machining safety practices and rules to authorized personnelDevelop, implement, and enforce machine use authorization procedures, rules, and training requirements as they apply to safe machine tool useImmediately correct machine safeguard deficiencies or prevent access to the machine until repairedSecure machining areas and equipment to prevent unauthorized use of machine toolsEnsure authorized machine tool users fulfill their responsibilitiesContact the machine tool user’s supervisor, and restrict access when personnel fail to follow safety requirements5.1.3.6Authorized Machine Tool UsersAuthorized machine tool users willDemonstrate proficiency in safe machine tool operation prior to using equipmentUnderstand and practice approved machine safeguarding methodsNot defeat or remove safety devices or guards or operate machines without safeguards in place and in proper working orderBe knowledgeable of safety requirements and machining guidelines and adhere to themComplete required training or a demonstration of proficiency and obtain authorization prior to operating machine toolsWear personal protective equipment (PPE) as requiredPractice good housekeepingReport machine safeguarding malfunctions or problems to supervisor immediatelyReport unauthorized or unsafe use of machine tools if observed5.2 Procedures and Specific RequirementsAccident risks can be reduced with adequate machine safeguarding. Identifying obvious and hiddenhazards should be the first step in planning and reviewing the need for machine tool safeguarding. Theinformation presented in this chapter should be considered as a starting point.Most incidents leading to injury are the result of inadvertent or unwise contact with moving machine parts.Because of the great diversity of machine designs and functions, appropriate safeguarding to protectChapter 39: Machine Safeguarding SLAC Environment, Safety, and Health Manual workers from such hazards may also have numerous forms. Certain principles, however, are basic to anyeffective safeguarding design.5.2.1Machine Safeguarding Evaluation and DesignA uniform process should be applied and used to evaluate each of the hazards on the machine to developthe required level of safeguarding. The evaluation can be performed by a knowledgeable and experienced person internal to SLAC, or for more complicated machine designs and safeguarding issues, the evaluation can be conducted by a qualified third party.The OSHA/ANSI hierarchy for controlling machine hazards is as follows:1.Eliminate the hazard by design2.Control the hazard by guarding or devices3.Warnings4.Personal protective equipment5.TrainingIf the results of the hazard evaluation show the equipment to be safe (that is, poses no hazard to theemployee), changes to the equipment may not be necessary. This may be true for manually-poweredequipment.See Section 6, “Exhibits”, Machine Safeguarding Design Considerations, for further explanations andinformation.5.2.2General Safeguarding Methods and OptionsSee Section 6, “Exhibits”, Machine Safeguarding General Methods and Options, for general ideas andapproved types of guards and devices.5.2.3Equipment-specific TechniquesSee Section 6, “Exhibits”, Machine Guarding Equipment-specific Techniques, for information on therecommended techniques for the guarding of specific types of machines.5.2.4Equipment MaintenanceMachine custodians will establish and follow a program of periodic and regular inspections andmaintenance of their equipment to ensure that machines, parts, and auxiliary equipment are in a safeoperating condition and necessary safeguards are present. Records of these inspections should bemaintained and made available for inspection upon request.Only authorized personnel will be permitted to maintain or repair machine tools. When service occurs that requires entry of any body part into a danger zone within the equipment, or unexpected startup orSLAC Environment, Safety, and Health Manual Chapter 39: Machine Safeguarding energizing of the machine could cause injury, maintenance personnel will first isolate hazardous energies as required by the SLAC Lock and Tag Program for the Control of Hazardous Energy.55.2.5Other Requirements5.2.5.1Positive Disconnecting MeansTo enable proper isolation of hazardous energies before and during equipment maintenance and repair,machines and equipment operated by electric motors or other hazardous energy will be provided with apositive disconnecting means. Examples of positive disconnecting means include quick disconnect knifeswitches, circuit breakers, valves, and power cords and plugs. Push buttons, selector switches, softwareinterlocks, control circuit type devices, and computer controlled software cannot be used to isolatehazardous energy.5.2.5.2Stop Buttons and Power ControlsMachines should have an emergency power off (EPO) or stop button or other readily-accessible and clearly designated power switch within easy reach of the operator to cut off the power to each machine. The power controls must be located so as to make it unnecessary to reach over or near the hazard to make adjustments.For larger machines, power switches should be located in multiple locations on various sides so that power can be easily deactivated by bystanders in case of emergency.5.2.5.3Machine AnchoringMachines designed for a fixed location will be securely anchored to prevent walking or moving due tovibration, rotation, or seismic activity.5.2.5.4Manual ResetProper restart systems must be installed on all powered equipment and tools so that manual reset is required to restart the tool after it has been stopped by any safety device or mechanism. For example, if aninterlocked guard stops tool operation when the guard is removed, manual reset is required to restart thetool after the guard is replaced. Replacing the guard alone must not allow the tool to restart. Manual reset is typically achieved by requiring the tool operator to press a reset button in order to restart the tool.5.2.5.5Anti-Restart DevicesAnti-restart devices (ARDs) or other effective provisions must be present on all woodworking machinesand mechanical power presses which could create hazardous conditions to employees if motors were tosuddenly restart after a restoration of voltage conditions following a power failure. It is stronglyrecommended that any machine that could pose a hazard to employees upon restoration of power also beprovided with an ARD. Although there is no explicit regulatory requirement for metal working or othermachines to have ARDs, the machines should at a minimum be listed and labeled by a NationallyRecognized Testing Laboratory (NRTL) and conform to the applicable standard in the American National Standards Institute B11 series (see Section 7, “References”)5 SLAC Lock and Tag Program for the Control of Hazardous Energy (SLAC-I-730-0A10Z-001),/esh/hazardous_activities/lockout_tagout/locktag.pdfChapter 39: Machine Safeguarding SLAC Environment, Safety, and Health Manual In addition, the machine should be evaluated (see Section 5.2.1, “Machine Safeguarding Evaluation andDesign”) to determine the risk to employees if an ARD is not present. A sudden restoration of powerfollowing an interruption should not create hazardous conditions to employees. (See Section 6, “Exhibits”, Machine Safeguarding Anti-restart Devices, for more information and detailed requirements.)5.2.5.6Malfunctioning Machinery or SafeguardsMalfunctioning machinery or safeguards must be reported immediately to the area supervisor or machine custodian. If the malfunction presents a safety hazard, the machine must be taken out of service bydisconnecting and locking out the power source(s). A warning sign indicating the problem should be placed on the machine to communicate its status to affected personnel.5.2.5.7Safe Operating ProceduresMachine users will follow safe operating procedures as developed and enforced by the machine custodian or supervisor in charge. An example of a written program containing acceptable safe operating procedures is available (see Section 6, “Exhibits”, Machine Safeguarding Safe Operating Procedure Topics).5.3Training5.3.1RequiredTraining is a necessary part of any effort to provide protection against machine-related hazards. Thefollowing two coursesES&H Course 136, Lock and Tag – Affected Employee6ES&H Course 198, Machine Guarding7are required for personnel meeting any of these conditions:Any person becoming qualified in machine operation if required by a supervisor or machine custodian Persons new to machine shops or machine operationThose involved in machine design or maintenancePersonnel who service machine safeguards5.3.2On-the-Job TrainingAll personnel who operate machines should be trained by machine custodians or supervisors in thefollowing subject areas through hands-on training:Identification and description of hazards associated with each machineList of actions that promote good safety practices (safe operating procedures)Procedures to follow in the event of accident or injury6 https:///esh-db/training/slaconly/bin/catalog_item.asp?course=1367 https:///esh-db/training/slaconly/bin/catalog_item.asp?course=198SLAC Environment, Safety, and Health Manual Chapter 39: Machine SafeguardingProcedures for safe use, cleaning, routine maintenance and repair activitiesInstruction on tool-specific PPE and clothing requirements for each machineTraining must also be provided to machine operators and maintenance personnel when safeguards are used.Safeguard training should involve instruction or hands-on training in the following areas as a minimum:A description and identification of the hazards associated with the machine(s)A description of the safeguards and their functionsInstruction on how to use the safeguardsInstruction on how, and under what circumstances safeguards may be removed, and by whomInstruction on what to do if a safeguard is missing, damaged, or inadequateIt is strongly recommended that verification of effective training and competency involve a machine-specific demonstration of proficiency by the student, written test, and continued supervisor observationduring a probationary period.5.3.3Recommended TrainingES&H Course 222, Hearing Conservation8ES&H Course 222ME, Hearing Conservation Medical EvaluationES&H Course 255, Personal Protective Equipment96ExhibitsMachine Shop Locations (SLAC-I-730-0A21S-002)10Machine Safeguarding Terms (SLAC-I-730-0A21S-003)11Machine Safeguarding Design Considerations (SLAC-I-730-0A21S-004)12Machine Safeguarding General Methods and Options (SLAC-I-730-0A21L-001)13Machine Safeguarding Equipment-specific Requirements (SLAC-I-730-0A21S-005)14Machine Safeguarding Anti-restart Devices (SLAC-I-730-0A21S-006)158 https:///esh-db/training/slaconly/bin/catalog_item.asp?course=2229 https:///esh-db/training/slaconly/bin/catalog_item.asp?course=25510 /esh/eshmanual/references/machineShops.pdf11 /esh/eshmanual/references/machineGlossary.pdf12 /esh/eshmanual/references/machineDesign.pdf13 /esh/eshmanual/references/machineGeneralOptions.pdf14 /esh/eshmanual/references/machineEquipment.pdf15 /esh/eshmanual/references/machineAntirestart.pdfChapter 39: Machine Safeguarding SLAC Environment, Safety, and Health Manual Machine Safeguarding Safe Operating Procedure Topics (SLAC-I-730-0A21S-007)167ReferencesSLAC Environment, Safety, and Health Manual (SLAC-I-720-0A29Z-001)17Chapter 19, “Personal Protective Equipment”18Chapter 25, “Tools – Power and Hand Operated”19Chapter 37, “Emergencies”20SLAC Lock and Tag Program for the Control of Hazardous Energy (SLAC-I-730-0A10Z-001)21OSHA Publication 3067, “Concepts and Techniques of Machine Safeguarding” (revised 1992)American National Standards Institute22ANSI B11.1, “Safety Requirements for the Construction, Care, and Use of Mechanical Power Presses”ANSI B11.2, “Safety Requirements for Construction, Care, and Use of Hydraulic Power Presses”ANSI B11.3, “Safety Requirements for the Construction, Care, and Use of Mechanical Power Press Brakes”ANSI B11.4, “Safety Requirements for the Construction, Care, and Use of Shears”ANSI B11.6, “Safety Requirements for the Construction, Care, and Use of Lathes”ANSI B11.7, “Safety Requirements for the Construction, Care, and Use of Cold Headers and Cold Formers”ANSI B11.8, “Safety Requirements for the Construction, Care, and Use of Drilling, Milling, and Boring Machines”ANSI B11.9, “Safety Requirements for the Construction, Care, and Use of Grinding Machines”ANSI B11.10, “Safety Requirements for the Construction, Care, and Use of Metal Sawing Machines”ANSI B11.11, “Safety Requirements for Gear and Spline Cutting Machines”ANSI B11.12, “Safety Requirements for Roll-forming and Roll-bending Machines”16 /esh/eshmanual/references/machineTopics.pdf17 /esh/eshmanual/18 /esh/general/ppe/policies.htm19 /esh/hazardous_activities/tools_powerhand/policies.htm20 /esh/emergency/chapter/policies.htm21 /esh/hazardous_activities/lockout_tagout/locktag.pdf22 See the SLAC Library, /library/, for available standards. For a list ofANSI standards, see the American National Standards Institute “Standards Search”,/ansidocstore/find.asp12/21/2005 (updated 10/9/2006) SLAC-I-720-0A29Z-001-R023.1 39-11SLAC Environment, Safety, and Health Manual Chapter 39: Machine Safeguarding ANSI B11.13, “Safety Requirements for the Construction, Care, and Use of Single- and Multiple Spindle Automatic Screw/Bar and Chucking Machines”ANSI B11.14, “Coil Slitting Machines – Safety Requirements for Construction, Care, and Use”ANSI B11.15, “Safety Requirements for Pipe, Tube, and Shape Bending Machines”ANSI B11.16, “Safety Requirements for Powder / Metal Compacting Presses”ANSI B11.17, “Safety Requirements for Horizontal Hydraulic Extrusion Presses”ANSI B11.18, “Safety Requirements for Construction, Care, and Use of Machines and Machinery Systems for Processing Strip, Sheet, or Plate from Coiled Configuration”ANSI B11.19, “Performance Criteria for Safeguarding”ANSI B11.20, “Safety Requirements for Integrated Manufacturing Systems”ANSI B11.21, “Safety Requirements for Design, Construction, Care, and Use of Lasers for Processing Materials”ANSI B11.22, “Safety Requirements for Turning Centers and Automatic, Numerically Controlled Turning Machines”ANSI B11.23, “Safety Requirements for Machining Centers and Automatic, Numerically Controlled Milling, Drilling and Boring Machines”ANSI B11.24, “Safety Requirements for Transfer Machines”8OwnershipDepartment: Chemical and General SafetyProgram: Machine SafeguardingOwner: Program Manager, Linda Knudsen39-12 SLAC-I-720-0A29Z-001-R023.1 12/21/2005 (updated 10/9/2006)。