GRINDERS. 2. Referenced Documents. 1. Scope

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1 Phone: (720) Fax: (720) GRINDERS 1. Scope 1.1 The purpose of this guideline is to provide basic information regarding the safety protection and protocol needed while using portable and fixed abrasive wheel grinders. 1.2 Grinders are used in the preparation and finishing areas in a galvanizing facility. Grinders are used as an aid for mechanical cleaning of difficult contaminants from the surface of the steel prior to any of the chemical cleaning steps. Grinders are also used in the finishing aspect of the galvanized steel. Grinders are used to remove sharp edges from the galvanized steel articles. Grinders can also be used to remove some of the galvanized coating prior to welding to reduce fume generation and to provide a cleaner weld-joint. 1.3 The OSHA regulation for fixed abrasive wheel grinders is in machine guarding listed in 29 CFR and The regulation for a portable hand held grinder is listed in 29 CFR This guideline gives reference to galvanizers responsibilities involving the use of fixed abrasive wheel and portable hand held grinders. The appropriate safety measures and personal protective equipment are discussed. Disclaimer 2. Referenced Documents J. J. Keller, OSHA 1910 Guide, (Updated June 1999) (Updated May 1993) (Updated November 1993) (Updated November 1993) OSHA Publication, Self-Inspection Checklists, OSHA Office of Training and Education, 1997 U.S. Department of Labor, Occupational Safety and Health Administration, Hand and Power Tools OSHA 3080, 1998 Revised. 3. Terminology 3.1 Definitions of Terms Specific to This Guideline abrasive wheel a cutting tool consisting of abrasive grains held together by organic or inorganic bonds. Diamond and reinforced wheels are included flanges collars, discs or plates between which wheels are mounted and are referred to as adapter, sleeve or backup type. For a full description, refer to (c). 1 The material contained herein has been developed to provide accurate and authoritative information about the practices and procedures to protect employees in the galvanizing industry from the hazards of the use of grinders. This material provides general information only and is not intended as a substitute for competent professional examination and verification as to suitability and applicability. The publication of the material herein is not intended as a representation or warranty on the part of the, Inc. Anyone making use of this information assumes all liability arising from such use.

2 3.1.3 off-hand grinding grinding of any material or part that is held in the operator s hand point of operation the area on a machine where work is actually performed on the material being processed portable grinding a grinding operation where the grinding machine is designed to be hand held and may be easily moved from one location to another protective shield or guard a device or guard attached to the muzzle end of the tool that is designed to deflect flying particles ring test a test to check if the wheel is in proper working order. The ring test is conducted by tapping the wheels gently with a nonmetallic tool, such as a plastic screwdriver handle or wooden mallet. A wheel in good condition will emit a metallic ring. A wheel is rejected if the wheel sounds dead or cracked. The ring test does not apply to small wheels of 10 cm (4 in) diameter and smaller safety guard an enclosure designed to restrain the pieces of the grinding wheel and furnish all possible protection in the event that the wheel is broken in operation snagging grinding that removes relatively large amount of material without regard to close tolerances or surface finish requirements. 4. OSHA Regulation , Subpart O Machinery and Machine Guarding 4.1 Machines, specifically abrasive wheel machinery and portable powered tools with abrasive wheels, are required to be provided with safety guards to protect employees in the machine area. The safety guards protect the employees against hazards created by points of operation, moving or rotating parts, sparks, flying chips, etc. Examples of safety guard methods are barrier guards, two-hand tripping devices, and electronic safety devices Abrasive wheel machinery is a type of bench and floor standing machine that uses an abrasive wheel to grind material and is at a fixed location. Portable grinders are portable powered tools equipped with an abrasive wheel that can be easily moved to different locations. Abrasive wheel machinery and portable grinding powered tools are required to have safety guards. 4.2 A general requirement for machine safety guards is to be affixed to the machine where possible and secured elsewhere if for any reason attachment to the machine is not possible. The safety guard shall not offer an accident hazard in itself. 4.3 The point of operation of machines whose operation exposes an employee to injury shall be guarded The safety guard shall be in conformity to appropriate standards. In the absence of applicable standards, the safety guard shall be designed and constructed to prevent the operator from having any part of the body in the dangerzone during the operating cycle Special handtools for placing and removing material shall permit easy handling of material without the operator placing a hand in the danger-zone. Such tools shall not be used in place of other guarding required but should only be used to supplement the protection provided A type of machine that usually requires point of operation guarding is the portable power tool. 4.4 In anchoring fixed machinery, the machines shall be securely anchored to prevent unintended movement. 5. OSHA Regulation Abrasive Wheel Machinery 5.1 Machine guarding is also used for abrasive wheel machinery. This only applies to machines provided with safety guards with the following exceptions: 2

3 Wheels used for internal work while inside the work being ground Mounted wheels two inches and smaller in diameter used in portable operations Grinding wheels in the combinations of Types 16, 17, 18, 18R, and 19 cones, plugs, and threaded hole pot balls where the work offers protection Diagrams and descriptions of abrasive wheel equipment are in Appendix The guard design shall cover the spindle end, nut and flange projections. The safety guard shall be mounted to maintain proper alignment of the wheel, and the strength of the fastenings shall exceed the strength of the guard. 5.3 Work rests shall be used to support the work on off-hand grinding machines. Safety guards may be constructed so that the spindle end, nut, and outer flange are exposed on all operations where the work provides a suitable measure of protection to the operator The side covers of the guard may be omitted when the nature of the work entirely covers the side of the wheel The work rests shall be of rigid construction and designed to be adjustable to compensate for wheel wear. Work rests shall be kept adjusted closely to the wheel with a maximum opening of one-eighth inch. This is to prevent the work from being jammed between the wheel and the work rest resulting in wheel breakage The work rest shall be securely clamped after each adjustment. The adjustment shall not be made with the wheel in motion. 5.4 The excluded machinery from this regulation, , are natural sandstone wheels and metal, wooden, cloth, or paper discs, having a layer of abrasive on the surface. 5.5 The guard design specification shall comply with the American National Standard Safety Code for the Use, Care, and Protection of Abrasive Wheels, ANSI B This requirement does not apply to the material listed in OSHA Regulation Hand and Portable Powered Tools and Equipment 6.1 An employer is responsible for the safe condition of tools and equipment used by employees, but the employees have the responsibility for properly using and maintaining tools. This includes tools and equipment that may be furnished by employees. 6.2 For cleaning purposes, compressed air shall not be used except when reduced to less than 30 psi and only with effective chip guarding and personal protective equipment. 7. OSHA Regulation Guarding of Portable Powered Tools 7.1 Portable grinding tools need to be equipped with safety guards to protect workers not only from the moving wheel surface, but also from flying fragments in case of breakage. 7.2 All hand-held horizontal, vertical, and angle grinders with wheels greater than two inches in diameter shall be equipped with a constant pressure switch or control. This may have a lock-on control if turn-off can be accomplished by a single motion of the same finger(s) that turn it on All other hand-held powered grinders with wheels two inches in diameter or less may be equipped with a positive on-off control, or the safety guards described in The operating control on hand-held power tools shall be located to minimize the possibility of its accidental operation, if this would constitute a hazard to employees. 7.4 Portable abrasive wheels shall be used only on machines provided with safety guards. The requirements are the same as the OSHA 3

4 regulation on abrasive wheel machinery There are several exceptions to the use of safety guards for portable abrasive wheels. On all operations where the work provides a suitable measure of protection to the operator, safety guards may be constructed so that the spindle end, nut and outer flange are exposed. The side covers of the guard may be omitted where the nature of the work is to cover the entire side of the wheel. The spindle end, nut, and outer flange may be exposed on portable machines designed for, and used with, type 6, 11, 27, and 28 abrasive wheels, cutting off wheels, and tuck pointing wheels. 7.5 Vertical portable grinders shall also be supplied with safety guards. Safety guards used on machines known as right angle head or vertical portable grinders shall have a maximum exposure angle of 180 degrees. The guard shall be located between the operator and the wheel during use. Adjustment of the guard shall be such that pieces of an accidentally broken wheel will be deflected away from the operator. 7.6 For other portable grinders, the maximum angular exposure of the grinding wheel periphery and sides for safety guards used shall not exceed 180 degrees, and the top half of the wheel shall be enclosed at all times. 7.7 Immediately before mounting, all abrasive wheels shall be closely inspected and sounded by the user using a ring test to make sure they have not been damaged in transit, storage, or otherwise The spindle speed of the machine shall also be checked before mounting of the wheel to be certain that it does not exceed the maximum operating speed marked on the wheel Grinding wheels shall fit freely on the spindle and remain free under all grinding conditions. A controlled clearance between the wheel hole and the machine spindle (or wheel sleeves or adaptors) is essential to avoid excessive pressure caused by mounting and/or spindle expansion. To accomplish this, the machine spindle shall be made to be nominal (standard) size plus zero, minus inch, and the wheel hole shall be made suitably oversize to assure safety clearance under the conditions of operating heat and pressure. 7.8 All contact surfaces of wheels, blotters, and flangers shall be flat and free of foreign matter. When a bushing is used in the wheel hole, it shall not exceed the width of the wheel and shall not contact the flanges. 7.9 The excluded machinery from this regulation, , are natural sandstone wheels and metal, wooden, cloth, or paper discs, having a layer of abrasive on the surface. 8. Maintenance of Portable Grinders and Abrasive Wheels 8.1 Portable grinders and fixed abrasive wheels must be working properly before an employee uses it. This involves being sure that the machine is operating properly and routine maintenance is performed on the machine 8.2 The following are maintenance procedures for portable grinders. Clean and service grinders according to manufacturer s recommendations. Record all maintenance for grinders. Check that grinders do not vibrate or operate roughly. Hand-held grinders must have proper wheel guards. Use racks or hoists to store portable grinders. Inspect all wheels for cracks and defects before operating. Insure that the mounting flange surfaces are clean and flat. 4

5 Use the mounting blotters supplied. Run newly mounted wheels at operating speeds for 1 minute before grinding. The maximum speed in revolutions per minute (rpm) is marked on every wheel. Never exceed this speed. Check that the wheel speed marked on the wheel is equal to or greater than the maximum speed of the grinder. Measure the speed of any new machine. Take several readings. Measure the speed of your governor-controlled, air-driven grinders after twenty hours of use or every week, whichever comes first. Measure the speed after any repairs. Measure the speed of electrically driven grinders monthly and after repairs. 8.3 The following are maintenance procedures for abrasive wheels. All flanges shall be maintained in good condition. When the bearing surfaces become worn, warped, sprung, or damaged they should be trued or refaced. Guards must be provided and adjusted to protect the employee. Replace damaged guards because if an abrasive wheel breaks while rotating, it can cause serious injury. Fasten pedestal and bench grinders securely. Dress wheels regularly. Do frequent, light dressings rather than heavy dressings. Support dressing tools to apply leverage without undue effort. With revolving cutter dressing tools use the lugs as anchors. Replace worn wheels if they cannot be dressed. Visually inspect wheels for possible damage before mounting. Perform the ring test to check if the wheel is in proper working order. All abrasive wheels are fragile. Handle wheels carefully and avoid dropping or bumping. Transport wheels in containers designed to provide support for the wheels, if they are too heavy to carry by hand. Do not pile items such as tools on top of wheels Store wheels in racks or bins with dividers for different types of wheels. Place straight or tapered wheels on end in a cradle or choked position to prevent rolling. Never store wheels near excessive heat or cold, in contact with oil or moisture, or in drawers with loose tools. Do not leave grinding wheels standing in liquids. The liquid can cause balance problems. Follow the manufacturer s instructions for length of time a wheel should be stored and how to store thin wheels. 9. Safety Precautions when using Portable Grinders and Abrasive Wheels 9.1 In Appendix 2 is a checklist for machine guarding and abrasive portable wheel equipment. The following are safety precautions for portable grinders. Ensure that an unattended machine will not operate by checking the constant pressure switch. Wear appropriate personal protective equipment such as safety glasses, 5

6 goggles, and face protection to protect against flying particles. Gloves, aprons, metatarsal safety boots, and respiratory protection may be required, depending on the work. Avoid using grinders near flammable materials. Portable grinders should not be clamped in a vise for grinding handheld work. Liquid coolants should not be used with portable grinders. Do not force wheels onto a grinder or change mounting hole sizes. The mounting nut should not be tightened excessively. 9.2 The following are safety precautions for abrasive wheels. Ensure all the guards are in place and secure before using a grinder. Adjust tool rest to within 3 mm (1/8 in) of wheels. Never adjust rests while wheels are moving. Work rest height should be on horizontal center of the machine spindle. Maintain 6 mm (1/4 in) wheel exposure with a tongue guard or a movable guard. Stand to one side of the grinder until the wheel reaches operating speed. Wheels are made only for grinding certain items. Do not grind rough forgings on a small precision grinding wheel. Select the right wheel for the job. A wheel is dangerous when used for work for which it was not designed. Booklets from wheel and machine manufacturers provide technical information on wheel selection and proper use. Wood, plastics, and non-iron metals should not be used for grinding on ordinary wheels. Ensure the grinder speed does not exceed the operating speed marked on the wheel. Use only wheels marked with the type of wheel and maximum speed in revolutions per minute (rpm). Wear proper personal protective equipment eye, ear and face protection, metatarsal safety boots where required, respiratory protection may be required depending on the work, and wear gloves only when necessary. Safety requires that floors be kept as clean and dry as possible to prevent accidental slips with or around dangerous hand tools. Do not use a wheel that has been dropped. Do not grind on the regular wheel side. 9.3 Safety guards must meet these minimum requirements. Prevent contact prevent hands, arms, and any other part of a worker s body from making contact with dangerous moving parts. A good safety guard system eliminates the possibility of the operator or another worker placing parts of their bodies near hazardous moving parts. Secure should not be able to easily remove or tamper with the safety guard. The safety guards should be made of durable material that will withstand the conditions of normal use. The safety guards must also be firmly secure to the machine. Protect from falling objects the safety guard should ensure that no objects could fall into moving parts. Create no new hazards 6

7 Create no interference any safety guard that impedes a worker from performing the job quickly and comfortably might soon be overridden or disregarded. A proper safety guard can actually enhance efficiency since it can relieve the worker s apprehensions about injury. Allow safe lubrication should be able to lubricate the machine without removing the safety guard. Locating oil reservoirs outside the guard, with a line leading to the lubrication point, will reduce the need for the operator or maintenance worker to enter the guarded area. 10. Hazard Areas when using Grinders 10.1 When grinding on galvanized steel, zinc slivers and/or dust can hit an employee. Proper protective equipment should be worn Grinders can catch on clothing and hair. To protect an employee, loose clothing should be tucked in. Long hair should be tucked under a hard hat. The grinder should be pointed away from an employee s body. A file can be used instead of a grinder where appropriate The grinding disc can fly off. When grinding, the employee should watch the product that is being ground and avoid sharp corners that can tear the disc. The discs should also be changed regularly Grinders can give shocks. The cords should be checked and repaired, if needed. Keep electric cables and cords clean and free from kinks. Check the power cord for any breaks or cut in the insulation that could pose a shock hazard. The floors should be kept dry in the area where the grinders are being used. The use of wet gloves should also be avoided Portable power tools can present safety hazards. Use care to avoid burns, cuts, electric shock, particles in the eyes and falling tools. When using grinding wheels, make sure that the wheel is firmly attached and machine guards are in place Never transport a tool by its cord When not being used, make sure all tools and their cords are properly stored and secured. Power extension cords on the floor create a stumbling or tripping hazard. Suspend power cords over aisles or work areas where possible. 11. Personal Protective Equipment 11.1 Engineering controls that eliminate the hazard at the source and do not rely on the worker s behavior for their effectiveness offer the best and most reliable means of guarding. Therefore, engineering controls must be the employer s first choice for eliminating machine hazards. Whenever engineering controls are not available or are not fully capable of protecting the employee, operators must wear protective clothing or personal protective equipment Personal protective equipment must be appropriate for the particular hazards, maintained in good condition, properly stored when not in use to prevent damage or loss, and kept clean, fully functional and sanitary Employees who use hand and power tools and who are exposed to the hazards of falling, flying, abrasive and splashing objects, or exposed to harmful dusts, mists, vapors, or gases, must be provided with the particular personal protective equipment necessary to protect them from these hazards Proper personal protective equipment should be used when doing any clean-up or touch-up work. The workpiece may still be hot from the galvanizing kettle so always wear gloves. Other personal protective equipment may include safety glasses, face shields, hearing protection, and respiratory protection. Appropriate clothes for the job activity should also be worn, such as coveralls, long pants and shirts, steel reinforced boots, and a hard hat. 7

8 11.4 Employees working in an area where grinding activities are being performed are encouraged, but not required, to wear ear protection In order to monitor the areas where grinders will be used, it is important to measure the dust and noise levels. This should be reviewed in accordance with the OSHA Occupational Noise and Exposure Regulation, According to , workers may not be exposed to more than the average of 85 decibels over an eight-hour period without hearing protection. Protection devices include earplugs, canal caps, enclosures, and ear muffs A dust mask is recommended to protect the respiratory system against irritating fumes, air particles and dust The use of respirators should be based on the hazard and only if engineering controls are not feasible. For more information on the respirator regulation, refer to OSHA standard, Respiratory Protection, Basic personal protective equipment should always be used. Safety glasses, goggles, face shield, visors, or masks protect eyes from splashes and flying debris. Particles from the finishing and repair area can be extremely hazardous to the eyes. The eye and face protection must meet the OSHA regulation, Eye and Face Protection, Around flammable substances, sparks produced by iron and steel hand tools can be a dangerous ignition source. Where this hazard exists, spark-resistant tools made from brass, plastic, aluminum or wood will be a safe alternative Thorough operator training should involve instruction or hands-on training in the following: A description and identification of the hazards associated with particular machines Safety guards, how they provide protection, and the hazards for which they are intended How to use the safety guards and why How and under what circumstances safety guards can be removed, and by whom (in most cases, repair or maintenance personnel only) What to do (e.g., contact the supervisor) if a safety guard is damaged, missing, or unable to provide adequate protection 12.3 This kind of training is necessary for new operators and maintenance or set-up personnel, when any new or altered safety guards are put in service, or when workers are assigned to a new machine or operation. 12. Training 12.1 Specific and detailed training is a crucial part of any effort to provide and use safety guards against machine-related hazards. 8