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Safeguarding Equipment and Protecting Employees from Amputations Small Business Safety and Health Management Series OSHA 3170-02R 2007 Contents [Introduction] [OSHA Standards] [National Consensus Standards] [Hazard Analysis] [Controlling Amputation Hazards] [Safeguarding Machinery] [Primary Safeguarding Methods] [Guards] [Safeguarding Devices] [Secondary Safeguarding Methods] [Probe Detection and Safety Edge Devices] [Awareness Devices] [Safeguarding Methods] [Safe Work Procedures] [Complementary Equipment] [Administrative Issues] [Inspection and Maintenance] [Lockout/Tagout] [Specific Machine Hazards and Safeguarding Methods] [Hazards of Mechanical Power Presses] [Safeguarding Mechanical Power Presses] [Other Controls for Mechanical Power Press Servicing and Maintenance] [Training] [Additional Requirements] [Power Press Brakes] [Hazards of Power Press Brakes] [Safeguarding Power Press Brakes] [Other Controls for Power Press Brakes] [Hazards of Conveyors] [Safeguarding Conveyors] [Other Controls for Conveyors] [Hazards of Printing Presses] [Safeguarding Printing Presses] [Other Controls for Printing Presses] [Hazards of Roll-Forming and Roll-Bending Machines] [Safeguarding Roll-Forming and Roll-Bending Machines] [Other Controls for Roll-Forming and Roll-Bending Machines] [Hazards of Shearing Machines] [Safeguarding Shearing Machines] [Other Controls for Shearing Machines] [Hazards of Food Slicers] [Safeguarding and Other Controls for Food Slicers] [Hazards of Meat Grinders] [Safeguarding and Other Controls for Meat Grinders] [Hazards of Meat-Cutting Band Saws] [Safeguarding and Other Controls for Meat-Cutting Band Saws] [Hazards of Drill Presses] [Safeguarding and Other Controls for Drill Presses] [Hazards of Milling Machines] [Safeguarding and Other Controls for Milling Machines] [Hazards of Grinding Machines] [Safeguarding and Other Controls for Grinding Machines] [Hazards of Slitters] [Safeguarding and Other Controls for Slitters] [OSHA Assistance] [References] [Appendix A. Amputation Hazards Not Covered in this Guide] [Appendix B. Amputation Hazards Associated with Other Equipment and Activities] [Appendix C. OSHA Regional Offices] List of Tables [Table 1. Commonly Used Machine Guards] [Table 2. Types of Safeguarding Devices] List of Figures [Figure 1. Rotating Motion] [Figure 2. Reciprocating Motion] [Figure 3. Transversing Motion] [Figure 4. Cutting Action] [Figure 5. Punching Action] [Figure 6. Shearing Action] [Figure 7. Bending Action] [Figure 8. In-Running Nip Points] [Figure 9. Fixed Guard on a Power Press] [Figure 10. Power Press with an Adjustable Barrier Guard] [Figure 11. Self-Adjusting Guard on a Radial Saw] [Figure 12. Interlocked Guard on a Roll Make-up Machine] [Figure 13. Pullback Device on a Power Press] [Figure 14. Restraint Device on a Power Press] [Figure 15. Presence-Sensing Device on a Power Press] [Figure 16. Two-Hand Control] [Figure 17. Power Press with a Gate] [Figure 18. Power Press with a Plunger Feed] [Figure 19. Shuttle Ejection Mechanism] [Figure 20. Safety Tripod on a Rubber Mill] [Figure 21. Typical Hand-Feeding Tools] [Figure 22. Properly Guarded Foot Control] [Figure 23. Part Revolution Mechanical Power Press with a Two-Hand Control] [Figure 24. Hand-Feeding Tools Used in Conjunction with Pullbacks on a Power Press] [Figure 25. Power Press Brake Bending Metal] [Figure 26. Two-Person Power Press Brake Operation with Pullbacks] [Figure 27. Belt Conveyor] [Figure 28. Screw Conveyor] [Figure 29. Chain Driven Live Roller Conveyor] [Figure 30. Slat Conveyor] [Figure 31. Roll-to-Roll Offset Printing Press] [Figure 32. Sheet-Fed Offset Printing Press] [Figure 33. Roll-Forming Machine] [Figure 34. In-Feed Area of a Roll-Forming Machine] [Figure 35. Hydraulic Alligator Shear] [Figure 36. Power Squaring Shear] [Figure 37. Meat Slicer] [Figure 38. Stainless Steel Meat Grinder] [Figure 39. Stainless Steel Meat-Cutting Band Saw] [Figure 40. Drill Press with a Transparent Drill Shield] [Figure 41. Bed Mill] [Figure 42. Horizontal Surface Grinder] [Figure 43. Paper Slitter] Introduction Amputations are among the most severe and disabling workplace injuries that often result in permanent disability. They are widespread and involve various activities and equipment. (The U.S. Bureau of Labor Statistics 2005 annual survey data indicated that there were 8,450 non-fatal amputation cases – involving days away from work – for all private industry. Approximately forty-four percent (44%) of all workplace amputations occurred in the manufacturing sector and the rest occurred across the construction, agriculture, wholesale and retail trade, and service industries.) These injuries result from the use and care of machines such as saws, presses, conveyors, and bending, rolling or shaping machines as well as from powered and non-powered hand tools, forklifts, doors, trash compactors and during materials handling activities. Anyone responsible for the operation, servicing, and maintenance (also known as use and care) of machines (which, for purposes of this publication includes equipment) — employers, employees, safety professionals, and industrial hygienists— should read this publication. Primary safeguarding, as used in this publication, includes control methods that protect (e.g., prevent employee contact with hazardous machine areas) employees from machine hazards through effective machine guarding techniques. In addition, a hazardous energy control (lockout/tagout) program needs to complement machine safeguarding methods in order to protect employees during potentially hazardous servicing and maintenance work activities. This guide can help you, the small business employer, identify and manage common amputation hazards associated with the operation and care of machines. The first two sections of the document, Recognizing Amputation Hazards and Controlling Amputation Hazards, look at sources of amputations and how to safeguard machinery and control employee exposure to hazardous energy (lockout/ tagout) during machine servicing and maintenance activities. The section on Specific Machinery Hazards and Safeguarding Methods identifies the hazards and various control methods for machinery associated with workplace amputations, such as: mechanical power presses, press brakes, conveyors, printing presses, roll-forming and roll-bending machines, shears, food slicers, meat grinders, meat-cutting band saws, drill presses, milling machines, grinding machines, and slitting machines. The information in this booklet does not specifically address amputation hazards on all types of machinery in general industry, construction, maritime and agricultural operations; however, many of the described safeguarding techniques may be used to prevent other amputation injuries. Additionally, while this manual concentrates attention on concepts and techniques for safeguarding mechanical motion, machines obviously present a variety of other types of energy hazards that cannot be ignored. For example, pressure system failure could cause fires and explosions. Machine electrical sources also pose electrical hazards that are addressed by other OSHA standards, such as the electrical standards contained in Subpart S. Full discussion of these matters is beyond the scope of this publication. For compliance assistance purposes, references and the appendices are provided on applicable OSHA standards, additional information sources, and ways you may obtain OSHA assistance. [Table of Contents] OSHA Standards Although this guide recommends ways to safeguard and lockout/tagout energy sources associated with machinery hazards, there are legal requirements in OSHA standards that you need to know about and comply with. The following OSHA standards are a few of the regulations that protect employees from amputation hazards. Consult these standards directly to ensure full compliance with the provisions as this publication is not a substitute for the standards. States with OSHA-approved plans have at least equivalent standards. For detailed information about machine guarding and lockout/tagout, see the following resources:
OSHA standards, directives, publications, and other resources are available online at www.osha.gov. [Table of Contents] National Consensus Standards OSHA recognizes the valuable contributions of national consensus standards and these voluntary standards may be used as guidance and recognition of industry accepted practices. For example, the American National Standards Institute (ANSI) publishes numerous voluntary national consensus standards on the safe care and use of specific machinery. These consensus standards provide you with useful guidance on how to protect your employees from machine amputation hazards and the control methods described may assist you in complying with OSHA performance-based standards. Furthermore, OSHA encourages employers to abide by the more current industry consensus standards since those standards are more likely to be abreast of the state of the art than an applicable OSHA standard may be. However, when a consensus standard addresses safety considerations, OSHA may determine that the safety practices described by that consensus standard are less protective than the requirement(s) set forth by the pertinent OSHA regulations. OSHA enforcement policy regarding the use of consensus standards is that a violation of an OSHA standard may be deemed de minimis in nature if the employer complies with a consensus standard (that is not incorporated by reference) rather than the OSHA standard in effect and if the employer's action clearly provides equal or greater employee protection. (Such de minimis violations require no corrective action and result in no penalty.) For example, the OSHA point-of-operation guarding provisions, contained in paragraph 1910.212(a)(3), require the guarding device to…be in conformance with any appropriate standards thereof, or in the absence of applicable specific standards, shall be so designed and constructed as to prevent the operator from having any part of his body in the danger zone during the operating cycle. The terms applicable standards or appropriate standards, as used in the context of 29 CFR 1910.212, are references to those private consensus standards that were adopted (source standards) or incorporated by reference in the OSHA standards. In some instances, a specific national consensus standard (that is not incorporated by reference or a source standard), such as an ANSI standard for a particular machine, may be used for guidance purposes to assist employers in preventing an operator from having any body part in the machine danger zone during the operating cycle. Also, OSHA may, in appropriate cases, use these consensus standards as evidence that machine hazards are recognized and that there are feasible means of correcting the hazard. On the other hand, some national consensus standards may sanction practices that provide less employee protection than that provided by compliance with the relevant OSHA provisions. In these cases, compliance with the specific consensus standard provision would not constitute compliance with the relevant OSHA requirement. [Table of Contents] Recognizing Amputation Hazards To prevent employee amputations, you and your employees must first be able to recognize the contributing factors, such as the hazardous energy associated with your machinery and the specific employee activities performed with the mechanical operation. Understanding the mechanical components of machinery, the hazardous mechanical motion that occurs at or near these components and specific employee activities performed in conjunction with machinery operation will help employees avoid injury. [Table of Contents] Hazardous Mechanical Components Three types of mechanical components present amputation hazards: Point of Operation is the area of the machine where the machine performs work – i.e., mechanical actions that occur at the point of operation, such as cutting, shaping, boring, and forming. Power-Transmission Apparatus is all components of the mechanical system that transmit energy, such as flywheels, pulleys, belts, chains, couplings, connecting rods, spindles, cams, and gears. Other Moving Parts are the parts of the machine that move while the machine is operating, such as reciprocating, rotating, and transverse moving parts as well as lead mechanisms and auxiliary parts of the machine. [Table of Contents] Hazardous Mechanical Motions A wide variety of mechanical motion is potentially hazardous. Here are the basic types of hazardous mechanical motions: Rotating Motion (Figure 1) is circular motion such as action generated by rotating collars, couplings, cams, clutches, flywheels, shaft ends, and spindles that may grip clothing or otherwise force a body part into a dangerous location. Even smooth surfaced rotating machine parts can be hazardous. Projections such as screws or burrs on the rotating part increase the hazard potential. Reciprocating Motion (Figure 2) is back-and-forth or up-and-down motion that may strike or entrap an employee between a moving part and a fixed object. Transversing Motion (Figure 3) is motion in a straight, continuous line that may strike or catch an employee in a pinch or shear point created by the moving part and a fixed object. Cutting Action: (Figure 4) is the action that cuts material and the associated machine motion may be rotating, reciprocating, or transverse. Punching Action (Figure 5) begins when power causes the machine to hit a slide (ram) to stamp or blank metal or other material. The hazard occurs at the point of operation where the employee typically inserts, holds, or withdraws the stock by hand. Shearing Action (Figure 6) involves applying power to a slide or knife in order to trim or shear metal or other materials. The hazard occurs at the point of operation where the employee typically inserts, holds, or withdraws the stock by hand. Bending Action (Figure 7) is power applied to a slide to draw or stamp metal or other materials in a bending motion. The hazard occurs at the point of operation where the employee typically inserts, holds, or withdraws the stock by hand. In-Running Nip Points (Figure 8), also known as “pinch points,” develop when two parts move together and at least one moves in rotary or circular motion. In-running nip points occur whenever machine parts move toward each other or when one part moves past a stationary object. Typical nip points include gears, rollers, belt drives, and pulleys. [Table of Contents] Hazardous Activities Employees operating and caring for machinery perform various activities that present potential amputation hazards. Machine set-up/threading/preparation,* Machine inspection,* Normal production operations, Clearing jams,* Machine adjustments,* Cleaning of machine,* Lubricating of machine parts,* and Scheduled and unscheduled maintenance.* * These activities are servicing and/or maintenance activities. [Table of Contents] Hazard Analysis You can help prevent workplace amputations by looking at your workplace operations and identifying the hazards associated with the use and care of the machine. A hazard analysis is a technique that focuses on the relationship between the employee, the task, the tools, and the environment. When evaluating work activities for potential amputation hazards, you need to consider the entire machine operation production process, the machine modes of operation, individual activities associated with the operation, servicing and maintenance of the machine, and the potential for injury to employees. The results from the analysis may then be used as a basis to design machine safeguarding and an overall energy control (lockout/tagout) program. This is likely to result in fewer employee amputations; safer, more effective work methods; reduced workers' compensation costs; and increased employee productivity and morale. [Table of Contents] Controlling Amputation Hazards Safeguarding is essential for protecting employees from needless and preventable injury. A good rule to remember is: Any machine part, function, or process that may cause injury must be safeguarded. In this booklet, the term primary safeguarding methods refers to machine guarding techniques that are intended to prevent or greatly reduce the chance that an employee will have an amputation injury. Refer to the OSHA general industry (e.g., Subpart O) and construction (e.g., Subparts I and N) standards for specific guarding requirements. Many of these standards address preventive methods (such as using barrier guards or two-hand tripping devices) as primary control measures; while other OSHA standards allow guarding techniques (such as a self-adjustable table saw guard) that reduce the likelihood of injury. Other less protective safeguarding methods (such as safe work methods) that do not satisfactorily protect employees from the machine hazard areas are considered secondary control methods. Machine safeguarding must be supplemented by an effective energy control (lockout/tagout) program that ensures that employees are protected from hazardous energy sources during machine servicing and maintenance work activities. Lockout/tagout plays an essential role in the prevention and control of workplace amputations. In terms of controlling amputation hazards, employees are protected from hazardous machine work activities either by: 1) effective machine safeguarding, or 2) lockout/tagout where safeguards are rendered ineffective or do not protect employees from hazardous energy during servicing and maintenance operations. Additionally, there are some servicing activities, such as lubricating, cleaning, releasing jams and making machine adjustments that are minor in nature and are performed during normal production operations. It is not necessary to lockout/ tagout a machine if the activity is routine, repetitive and integral to the production operation provided that you use an alternative control method that affords effective protection from the machine's hazardous energy sources. [Table of Contents] Safeguarding Machinery The employer is responsible for safeguarding machines and should consider this need when purchasing machinery. Almost all new machinery is available with safeguards installed by the manufacturer, but used equipment may not be. If machinery has no safeguards, you may be able to purchase safeguards from the original machine manufacturer or from an after-market manufacturer. You can also build and install the safeguards in-house. Safeguarding equipment should be designed and installed only by technically qualified professionals. If possible, the original equipment manufacturer should review the safeguard design to ensure that it will protect employees without interfering with the operation of the machine or creating additional hazards. Regardless of the source of safeguards, the guards and devices used need to be compatible with a machine's operation and designed to ensure safe operator use. The type of operation, size, and shape of stock, method of feeding, physical layout of the work area, and production requirements all affect the selection of safeguards. Also, safeguards should be designed with the machine operator in mind as a guarding method that interferes with the operation of the machine may cause employees to override them. To ensure effective and safe operator use, guards and devices should suit the operation. The Performance Criteria for Safeguarding [ANSI B11.19-2003] national consensus standard provides valuable guidance as the standard addresses the design, construction, installation, operation and maintenance of the safeguarding used to protect employees from machine hazards. The following safeguarding method descriptions are, in part, structured like and, in many ways are similar to this national consensus standard. [Table of Contents] Primary Safeguarding Methods Two primary methods are used to safeguard machines: guards and some types of safeguarding devices. Guards provide physical barriers that prevent access to danger areas. Safeguarding devices either prevent or detect operator contact with the point of operation or stop potentially hazardous machine motion if any part of an individual's body is within the hazardous portion of the machine. Both types of safeguards need to be properly designed, constructed, installed, used and maintained in good operating condition to ensure employee protection. [Table of Contents] Guards Guards usually are preferable to other control methods because they are physical barriers that enclose dangerous machine parts and prevent employee contact with them. To be effective, guards must be strong and fastened by any secure method that prevents the guard from being inadvertently dislodged or removed. Guards typically are designed with screws, bolts and lock fasteners and usually a tool is necessary to unfasten and remove them. Generally, guards are designed not to obstruct the operator's view or to prevent employees from doing a job. In some cases, guarding may be used as an alternative to lockout/tagout because employees can safely service or maintain machines with a guard in place. For example, polycarbonate and wire-mesh guards provide greater visibility and can be used to allow maintenance employees to safely observe system components. In other instances, employees may safely access machine areas, without locking or tagging out, to perform maintenance work (such as machine cleaning or oiling tasks) because the hazardous machine components remain effectively guarded. Guards must not create additional hazards such as pinch points or shear points between guards and other machine parts. Guard openings should be small enough to prevent employees from accessing danger areas. (See Table 1 and Figures 9 through 12 for commonly used machine guards.) [Table of Contents] Table 1. Commonly Used Machine Guards
[Table of Contents] Safeguarding Devices Safeguarding devices are controls or attachments that, when properly designed, applied and used, usually prevent inadvertent access by employees to hazardous machine areas by:
These types of engineering controls, which either prevent the start of or stop hazardous motion, may be used in place of guards or as supplemental control measures when guards alone do not adequately enclose the hazard. In order for these safeguarding devices to accomplish this requirement, they must be properly designed and installed at a predetermined safe distance from the machine's danger area. Other safeguarding devices (probe detection and safety edge devices) that merely detect, instead of prevent, inadvertent access to a hazard are not considered primary safeguards. (See Table 2 and Figures 13 through 17 for the types of safeguarding devices.) [Table of Contents] Table 2. Types of Safeguarding Devices
[Table of Contents] [Table of Contents] Secondary Safeguarding Methods Other safeguarding methods, such as those described in the Performance Criteria for Safeguarding(ANSI B11.19-2003), may also provide employees with some protection from machine hazards. Detection safeguarding devices, awareness devices, safeguarding methods and safe work procedures are described in this section. These methods provide a lesser degree of employee protection than the primary safeguarding methods and they are considered secondary control measures as they do not prevent employees from placing or having any part of their bodies in the hazardous machine areas. Secondary safeguarding methods are acceptable only when guards or safeguarding devices (that prevent you from being exposed to machine hazards) cannot be installed due to reasons of infeasibility. Where it is feasible to use primary safeguarding methods, secondary safeguarding methods may supplement these primary control measures; however, these secondary safeguarding methods must not be used in place of primary safeguarding methods. [Table of Contents] Probe Detection and Safety Edge Devices A probe detection device (sometimes referred to as a ring guard) detects the presence or absence of a person's hand or finger by encircling all or part of the machine hazard area. The ring guard makes you aware of your hand's entry into a hazardous area and usually stops or prevents a hazardous machine cycle or stroke, thereby reducing the likelihood of injuring yourself in the point of operation. These types of detection devices are commonly used on spot welders, riveters, staplers and stackers because primary safeguarding methods are not possible. However, probe detection devices do not prevent inadvertent access to the point-of-operation danger area; rather, they serve as a warning mechanism and may prevent the initiation of or stop the machine cycle if an employee's hand or finger(s) is too close to the hazard area. A safety edge device (sometimes called a bump switch) is another type of safeguard that detects the presence of an employee when they are in contact with the device's sensing edge. A safety edge device protects employees by initiating a stop command when the sensing surface detects the presence of a person; however, they do not usually, when used by themselves, prevent inadvertent access to machine danger areas. Therefore, additional guarding or safeguarding devices must be provided to prevent employee exposure to a machine hazard. [Table of Contents] Awareness Devices Awareness devices warn employees of an impending, approaching or present hazard. The first type is an awareness barrier which allows access to machine danger areas, but it is designed to contact the employee, creating an awareness that he or she is close to the danger point. Awareness signals, through the use of recognizable audible or visual signals, are other devices that alert employees to an approaching or present hazard. Lastly, awareness signs are used to notify employees of the nature of the hazard and to provide instructions and training information. OSHA standard 1910.145 provides design, application, and use specifications for accident prevention (danger, caution, safety instruction) signs and (danger, caution, warning) tags. [Table of Contents] Safeguarding Methods Safeguarding methods protect employees from hazards by the physical arrangement of distance, holding, openings or the positioning of the machine components to ensure that the operator cannot reach the hazard. Some safeguarding work methods include safe distance safeguarding, safe holding safeguarding and safe opening safeguarding. Requirements for these secondary control measures may be found in ANSI B11.19-2003. Proper training and supervision are essential to ensure that these secondary safeguarding methods are being used properly. Safeguarding work methods may require the use of awareness devices, including the use of accident prevention signs where there is a need for warning or safety instruction. Safe Distance Safeguarding Safeguarding by safe distance (by location) may involve an operator holding and supporting a work-piece with both hands at a predetermined minimum safe distance or, if both hands cannot be used to hold the work-piece at a distance so that the operator cannot reach the hazard with the free hand. For example, the feeding process itself can create a distance safeguard if the operators maintain a safe distance between their hands and the point of operation. Additionally, where material position gauges are used, they need to be of sufficient height and size to prevent slipping of the material past the gauges. Another example of a safe distance safeguarding method is the use of gravity feed methods that reduce or eliminate employee exposure to machine hazards as the part slides down a chute into the point of operation. Automatic and semiautomatic feeding and ejection methods can also protect the employee by minimizing or eliminating employee exposure with potentially hazardous machinery components. An employee places the part in a magazine which is then fed into the point of operation. Automatic and semiautomatic ejection methods include pneumatic (jet of air), magnetic, mechanical (such as an arm), or vacuum. Figures 18 and 19 illustrate different types of automatic feeding and ejecting methods. Safe Holding Safeguarding (Safe Work-Piece Safeguarding) Operator's hands are maintained away from the hazardous portion of the machine cycle by requiring that both hands are used to hold or support the work-piece, or by requiring that one hand holds the work-piece while the other hand operates the machine. For instance, if the stock is several feet long and only one end of the stock is being worked on, the operator may be able to hold the opposite end while performing the work. The operator's body parts are out of the machine hazard area during the hazardous portion of the machine cycle. However, this work method only protects the operator. Safe Opening Safeguarding This method limits access to the machine hazardous areas by the size of the opening or by closing off the danger zone access when the work-piece is in place in the machine. Operators are prevented from reaching the hazard area during the machine operation; however, employee access to the danger area is not adequately guarded when the work-piece is not in place. [Table of Contents] Safe Work Procedures Safe work procedures are formal, written instructions which describe how a task is to be performed. These procedures should incorporate appropriate safe work practices, such as prohibiting employees from wearing loose clothing or jewelry and requiring the securing of long hair with nets or caps. Clothing, jewelry, long hair, and even gloves can get entangled in moving machine parts. [Table of Contents] Complementary Equipment Complementary equipment is used in conjunction with selected safeguarding techniques and it is, by itself, not a safeguarding method. Some common complementary equipment used to augment machine safeguarding include: Emergency Stop Devices Emergency stop devices are designed to be used in reaction to an incident or hazardous situation and, as such, are not considered machine safeguarding. These devices, such as buttons, rope-pulls, cable-pulls, or pressure-sensitive body bars, neither detect nor prevent employee exposure to machine hazards; rather they initiate an action to stop hazardous motion when an employee recognizes a hazard and activates them. (See Figure 20.) Work-Holding Equipment Work-holding equipment is not used to feed or remove the work-piece, but rather to hold it in place during the hazardous portion of the machine cycle. Clamps, jigs, fixtures and back gauges are examples of work-holding equipment. This equipment may be used to reduce or eliminate the need for an employee to place their hands in the hazard area. Feeding and Ejection Systems A feeding and ejection system (e.g., a gravity fed chute; semi-automatic and automatic feeding and ejection equipment), by itself, does not constitute secondary safeguarding. However, the use of properly designed feed and ejection mechanisms can protect employees by minimizing or eliminating the need for them to be in a hazard area during the hazardous motion of the machine. Hand-Feeding Tools Operators can use tools to feed and remove material into and from machines so as to keep their hands away from the point of operation. However, this must be done only in conjunction with the guards and safeguarding devices described previously. Hand tools are not point-of-operation guarding or safeguarding devices and they need to be designed to allow employees' hands to remain outside of the machine danger area. Using hand tools requires close supervision to ensure that the operator does not bypass their use to increase production. It is recommended that these tools be stored near the operation to promote their use. To prevent injury and repetitive trauma disorders, hand-feeding tools should be shatterproof and ergonomically designed for the specific task being performed. (Figure 21 shows typical handfeeding tools.) Foot Controls Foot controls that are not securely fixed at a safe distance do not constitute machine safeguarding because they do not keep the operator's hands out of the danger area. If you use foot-actuated controls that are not single-control safeguarding devices, they will need to be used with some type of guard or other safeguarding device. Improperly used foot-actuated controls may increase productivity, but the freedom of hand movement increases the risk of a point-of-operation injury or amputation. Foot controls must be guarded to prevent accidental activation by another employee or by falling material. Do not ride the foot pedal. Ensure that the machine control circuit is properly designed to prevent continuous cycling. (See Figure 22 for an example of a properly guarded foot control.) [Table of Contents] Administrative Issues As an employer, you need to consider housekeeping practices, employee apparel, and employee training. Implement good housekeeping practices to promote safe working conditions around machinery by doing the following:
Employees should not wear loose-fitting clothing, jewelry, or other items that could become entangled in machinery, and long hair should be worn under a cap or otherwise contained to prevent entanglement in moving machinery. Adequate instruction in the safe use and care of machines and supervised on-the-job training are essential in preventing amputation injuries. Only trained employees should operate machinery. In addition to employee instruction and training, employers need to provide adequate supervision to reinforce safe practices. Take disciplinary action to enforce safe work practices and working conditions. [Table of Contents] Inspection and Maintenance Good inspection, maintenance and repair procedures contribute significantly to the safety of the maintenance crew as well as to the operators. To ensure the integrity of the machinery and machine safeguards, a proactive, versus a break-down maintenance program needs to be established based upon the:
[Table of Contents] Lockout/Tagout OSHA's lockout/tagout (LOTO) standard, 29 CFR 1910.147, establishes minimum performance requirements for controlling hazardous energy and it is intended to complement and augment machine safeguarding practices. The lockout/tagout standard applies only if employees are exposed to hazardous energy during servicing/maintenance activities. An employer may avoid the requirements of the LOTO standard if the safeguarding method eliminates your employees' exposure to the machine danger area during the servicing or maintenance work by using Machinery and Machine Guarding methods in accordance with the requirements contained in 29 CFR 1910, Subpart O. Additionally, because some minor servicing may have to be performed during normal production operations, an employer may be exempt from LOTO in some instances. Minor tool changes and adjustments and other minor servicing operations, which take place during normal production operations, are not covered by lockout/tagout if they are routine, repetitive and integral to the use of the machine for production and if work is performed using alternative effective protective measures that provide effective employee protection. In short, a hazardous energy control program is a critical part of an overall strategy to prevent workplace amputations during machine servicing and maintenance activities, such as during the setting up of machines for production purposes, bypassing guards to clear jams or lubricate parts, and inspecting, adjusting, replacing, or otherwise servicing machine parts. Machine amputations occur when an employer does not have or fails to implement practices and procedures to disable and control a machine's energy sources during machine servicing and maintenance work. [Table of Contents] Specific Machine Hazards and Safeguarding Methods As discussed earlier, 8,450 known non-fatal amputation cases (involving days away from work) occurred in 2005 for all of private industry. The most prevalent injury source was, by far, machinery, which accounted for approximately 60% (5,080 instances) of the amputation cases. 1 The machinery listed here cause amputation injuries, and appropriate safeguarding and hazardous energy control (lockout/tagout) methods are addressed in this section. Employers need to consult the OSHA standard for specific machinery to ensure compliance with all requirements. For other types of hazardous sources of injury, see Appendix B. [Table of Contents] Hazards of Mechanical Power Presses Although there are three major types of power presses—mechanical, hydraulic, and pneumatic— the machinery that accounts for a large number of workplace amputations are mechanical power presses. In mechanical power presses, tools or dies are mounted on a slide, or ram, which operates in a controlled, reciprocating motion toward and away from the stationary bed or anvil containing the lower die. When the upper and lower dies press together – to punch, shear or form – the work-piece, the desired piece is produced. Once the downstroke is completed, the re-formed work-piece is removed either automatically or manually, a new work-piece is fed into the die, and the process is repeated. (See Figure 23.) 1 U.S. Department of Labor, Bureau of Labor Statistics (BLS); Annual Survey data, Table R25. Number of nonfatal occupational injuries or illnesses involving days away from work by source of injury or illness and selected natures of injury or illness, 2005. For safeguarding purposes, part-revolution mechanical power presses can be equipped with presence-sensing devices, but full-revolution mechanical power presses cannot. NOTE: Likewise, most hydraulic power presses and their associated control systems are similar to part-revolution mechanical power presses in that the slide can be stopped at any point in the cycle. In order to ensure the integrity of the safety-related functions, safeguarding devices (such as presence-sensing devices) may only be used on hydraulic power presses that are properly designed and constructed (in accordance with good engineering practice) to accommodate the safeguarding system. Refer to OSHA's Machine Guarding eTool for additional information on hydraulic presses. Amputations occurring from the point of operation hazards are the most common types of injuries associated with mechanical power presses. Improperly applied safeguarding methods (such as using a guard with more than maximum allowable openings or 2-hand palm buttons that are mounted within the safety distance of the press) may allow operators unsafe access to the press's hazardous area. These unsafe conditions may result in an amputation when an operator, for example, instinctively reaches into the point of operation to adjust a misaligned part or release a jam. Also, amputations occur when an operator's normal feeding rhythm is interrupted, resulting in inadvertent placement of the operator's hands in the point of operation. Such injuries usually happen while the operator is riding the foot pedal. Additionally, some amputations are linked to mechanical (such as the failure of a single-stroke linkage), electrical (such as a control relay failure), or pneumatic (such as the loss of air pressure to the clutch/brake) machine component failure. Examples of inadequate or ineffective safeguarding and hazardous energy control practices include the following:
[Table of Contents] Safeguarding Mechanical Power Presses Mechanical power presses are extremely versatile and selecting appropriate safeguarding methods depends on the specific press design and use. You should consider the press, the type of clutch used, the stock size, the length of production runs, and the method of feeding. You can use primary safeguarding methods, such as guards or safeguarding devices, to prevent injuries. For example, 29 CFR 1910.217 requires employers to provide and ensure the use of point of operation guards or properly installed devices on every operation performed on a press when the die opening is greater than 1 / 4 inch. In addition, guards must conform to the maximum permissible openings of Table O-10 of 29 CFR 1910.217. Guards must prevent entry of hands or fingers into the point of operation through, over, under, or around the guard. [Table of Contents] Other Controls for Mechanical Power Press Servicing and Maintenance Secondary safeguarding methods may be used alone or in combination (to achieve near equivalent protection) only when the employer can show that it is impossible to use any of the primary safeguarding methods. The following are some work practices, complementary equipment and energy control measures that may be used to supplement primary safeguarding:
Additional power press energy control precautions (e.g., use of safety blocks; LOTO the press disconnect switch if re-energization presents a hazard) will be necessary if employees need to place their hands/arms in a press working area (the space between the bolster plate and the ram/slide) to perform the servicing and/or maintenance activity (such as adjusting, cleaning or repairing dies) because the inch or jog safety device will not protect employees from ram movement due to potential mechanical energy (resulting from the ram/slide position and associated gravitational force), press component or control system malfunction, or press activation by others. [Table of Contents] Training Training is essential for employee protection. As an employer, you should:
Additional Requirements In addition, work practices such as regular mechanical power press inspection, maintenance, and reporting are essential.
[Table of Contents] Power Press Brakes Power press brakes are similar to mechanical power presses in that they use vertical reciprocating motion and are used for repetitive tasks. Press brake operation is either mechanical or hydraulic. Press brakes are either general-purpose or special-purpose brakes, according to ANSI B11.3-2002, Safety Requirements for Power Press Brakes. General purpose press brakes have a single operator control station. A servo-system activates the special purpose brake, which may be equipped with multiple operator/helper control stations. (See Figure 25 for a power press brake operation.) [Table of Contents] Hazards of Power Press Brakes As with mechanical power presses, point of operation injuries are the most common type of injury associated with power press brakes. Here are some frequent causes of amputations from power press brakes:
[Table of Contents] Safeguarding Power Press Brakes Primary safeguarding methods, such as physical guards and point of operation safeguarding devices (movable barrier devices, presence-sensing devices, pull-back devices, restraint devices, single-and two-hand devices) can be used to effectively guard power press brakes. (Figure 26 shows a general-purpose power press brake used in conjunction with pullbacks.) Some safeguarding methods, such as presence-sensing devices, may require muting or blanking to allow the bending of material. Always ensure that these safety devices are properly installed, maintained, and used in accordance with the manufacturer's guidelines for the specific stock and task to be performed. Failure to do so could leave sensing field channels "blanked out" and expose operators to point-of-operation hazards as the safeguarding device's safety distance increases when blanking is used. In other instances, such as with special-purpose power press brakes, machines are equipped with advanced control systems that are adaptable to all forms of safeguarding concepts and devices, such as two-hand controls and multiple operator/helper actuating controls. For example, two-hand down, foot through (actuation) methods are used to safeguard employees while they operate press brakes. With this safeguarding system, an operator uses a two-hand control to lower the press brake ram, for example, to within 1 / 4 inch or less of the lower die (which is considered a safe opening). The operator then has the ability to maneuver and align the work-piece within this 1 / 4 inch safe opening area and he or she is protected from the amputation hazard. Then the foot control is used by the operator to safely actuate the machine to produce the desired product. Because of constraints imposed by certain manufacturing or fabricating processes, safeguarding by maintaining a safe distance from the point of operation may be acceptable. However, this is permitted only when safeguarding by barrier guard or safeguarding devices is not feasible (impossible) – that is, where the use of primary safeguarding method (such as a restraint device) is not feasible. Additional information about a safe distance safeguarding program can be found in OSHA Instruction 02-01-025 [CPL 2-1.25] – Guidelines for Point of Operation Guarding of Power Press Brakes. [Table of Contents] Other Controls for Power Press Brakes The following are some secondary safeguarding methods and complementary equipment that may be used to supplement primary safeguarding or alone or in combination when primary safeguarding methods are not feasible:
Ensure that proper safeguarding and lockout/ tagout procedures are developed and implemented for power press brakes. Train and supervise employees in these procedures and conduct periodic inspections to ensure compliance. [Table of Contents] Hazards of Conveyors Conveyors are used in many industries to transport materials horizontally, vertically, at an angle, or around curves. Many conveyors have different and unique features and uses, so that hazards vary due to the material conveyed, the location of the conveyor, and the proximity of the conveyer to the employees. Types include unpowered and powered, live roller, slat, chain, screw, and pneumatic. Conveyors eliminate or reduce manual material handling tasks, but they present amputation hazards associated with mechanical motion. (See Figures 27 through 30 for examples of common conveyors.) Conveyor-related injuries typically involve a employee's hands or fingers becoming caught in nip points or shear points on conveyors and may occur in these situations:
Other conveyor-related hazards include improperly guarded gears, sprocket and chain drives, horizontal and vertical shafting, belts and pulleys, and power transmission couplings. Overhead conveyors warrant special attention because most of the conveyor's drive train is exposed. Employees have also been injured or killed while working in areas underneath conveyors and in areas around lubrication fittings, tension adjusters, and other equipment with hazardous energy sources. [Table of Contents] Safeguarding Conveyors As conveyor hazards vary depending on the application, employers need to look at each conveyor to evaluate and determine what primary safeguarding methods and energy control (lockout/tagout) practices are required. Where necessary for the protection of employees, conveyors need to have mechanical guards that protect the employee from nip points, shear points, and other moving parts, including power-transmission apparatus. Guards may include barriers, enclosures, grating, fences, or other obstructions that prevent inadvertent physical contact with operating machine components, such as point of operation areas, belts, gears, sprockets, chains, and other moving parts. A brief description of the hazards and recognized safeguarding methods is presented for common types of conveyors. [Table of Contents] Other Controls for Conveyors The following are some secondary safeguarding methods, work practices, and complementary equipment that may be used to supplement primary safeguarding or alone or in combination when primary safeguarding methods are not feasible:
For emergency stop devices, you will need these engineering controls:
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