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3 2 SAFETY AND ENVIRONMENTAL 2.1 Introduction Surface preparation, thermal spraying, and sealing and painting operations expose workers to numerous potential health and safety hazards. Common health and safety hazards associated with the industry include (a) electric shock; (b) flammable and explosive solvents, gases, and fine particulate dusts and fumes; (c) confined space entry; (d) fall hazards; (e) exposure to high- intensity noise, ultraviolet light, and toxic materials; and (f) high-velocity particle impingement. While this guide does not purport to address all of the safety issues regarding TSMCs and their application, some of the more important safety concerns associated with the process are discussed below. It is recommended that all personnel involved with the thermal spray process be familiar with safe working practices and safety regulations in current standards and guides. These standards and guides include, but are not limited to, documents from the American National Standards Institute (ANSI), the American Welding Society (AWS), the Coast Guard Academy (CGA), the military, the National Association of Corrosion Engineers (NACE), the National Fire Protection Association (NFPA), the Occupational Safety and Health Administration (OSHA), and the Society for Protective Coatings (SSPC). Also refer to the U.S. Army Corps of Engineers's Manual, Safety--Safety and Health Requirements, EM 385-1-1, Washington, D.C., November 3, 2003. Some of these standards are listed in Section 10 of this guide. 2.2 Blast Cleaning 2.2.1 Equipment Maintenance and Use Maintain abrasive blast machines and equipment in accordance with the manufacturers' recommendations. Tag and remove from service worn or damaged components pending replacement or repair. 188.8.131.52 Hose connections. Use hoses and hose connections that do not allow electrostatic discharge. Use hose couplings and nozzles designed to prevent accidental disconnection. Use a "deadman" control device that automatically shuts off the flow of air and abrasive when the hose is dropped. Inspect hoses and fittings used for abrasive blasting frequently to ensure the timely replacement of worn parts and equipment. 184.108.40.206 Hose use. Blast hoses shall be kept as straight as possible. Use a large radius of curvature for any bends so as to avoid excessive friction and wear. Store hoses in cool dry areas to avoid accelerated degradation. Never point the blast nozzle at the body parts of any person. Relieve air pressure in the blast tank and system before working on the system. Use a "tag- out" labeling system during system maintenance. 220.127.116.11 Ventilation. Provide mechanical ventilation in blasting operations that are not performed in the open or in a properly designed and ventilated room.
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4 2.2.2 Personal Protective Equipment Wear respiratory protective devices--helmets, hand shields, eye protection (face shields or goggles), and appropriate protective clothing--during all blasting operations. For blasting in the open, use a mechanical filter respirator in conjunction with face shields and dust hoods. Alternatively, an air-line respirator may be used. For blasting in confined or enclosed spaces, a continuous flow air-line respirator, a full-face piece or helmet, and dust hood are required. 18.104.22.168 Respirators. The guidelines listed below should be followed when using respirators. · Compressed air should meet at least the requirements of the specification for Type 1, Grade D breathing air as described in CGA G 7.1 "Commodity Specification for Air." · Respiratory protection shall be in accordance with ANSI Z88.2. · All respiratory devices shall comply with the U.S. Bureau of Mines and the National Institute for Occupational Safety and Health (NIOSH). Respirators selected from those currently approved and certified by NIOSH/Mine Safety and Health Administration (MSHA) Section 134 should be used. · Use NIOSH-certified Type CE respirator and Type CE hood (air-line-supplied air hood with faceplate and devices to protect the wearer's eyes, face, chin, neck, shoulders, and upper body from rebounding abrasive blasting media). · Note: Personnel using/wearing respirators require "fit-testing" before they can legally work under these conditions. Also, beards can affect the efficacy of respirators. 22.214.171.124 Eye and body protection. The guidelines listed below should be followed when using eye and body protection. · Head protection shall be in accordance with ANSI Z89.1. Face shields or helmets shall be equipped with dust hoods to protect the eyes, face, chin, and neck. · Personnel in or near blasting operations should wear helmets, handshields, faceshields, or goggles conforming to ANSI Z87.1 and eye protection conforming to ANSI Z89.1. · Appropriate protective clothing shall be worn during spray operations. Clothing should be strapped tightly around wrists and ankles to prevent contact with abrasive dust. Open shirt collars and unbuttoned pocket flaps are unacceptable. High-top shoes should be worn and cuff-less trousers should cover the tops. · Blasting operators should wear heavy canvas or leather gloves and an apron or coveralls. Approved safety shoes should be worn to protect against foot injury. 126.96.36.199 Hearing protection. Noise levels generated during blasting and thermal spray operations can cause temporary or permanent hearing loss, damage, and fatigue. · Wear approved earmuffs and properly fitted approved earplugs when thermal spray operators and personnel are in the immediate vicinity of thermal spray operations to reduce the high-intensity noise levels to acceptable conditions. · All personnel in the vicinity of blasting operations shall be provided with hearing protection if the noise exposure exceeds the limitations established by OSHA in paragraph 1910.95, "Occupational Noise Exposure".
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5 2.2.3 Cleaning with Compressed Air Cleaning with compressed air should be restricted to systems where the air pressure has been reduced to 204 kPa (30 psi) or less. Cleaning operators should wear safety goggles or a face shield, hearing protection, and appropriate body covering. Compressed air or pressurized gas nozzles should never be pointed at other personnel or at exposed skin. 2.2.4 Cleaning with Solvents The guidelines listed below should be followed when cleaning with solvents. · The material safety data sheet (MSDS) for each solvent used must be readily available and should be consulted for specific solvent information, handling, and storage and disposal procedures, in addition to those listed here. · Flammable liquids with a closed-cup test flash point below 100°F (38°C) should not be used for cleaning purposes. · Sources of ignition should not be permitted in the vicinity of solvent cleaning if there is any indication of combustible gas or vapor present. · Measurements should be made to ensure that solvent vapors are not present during thermal spray operations, especially in confined spaces. Representative air samples should be collected from the breathing zone of workers involved in the cleaning process to determine the specific solvent vapor concentrations. · Worker exposures should be controlled to levels below the Occupational Safety and Health Administration (OSHA) Permissible Exposure Limit, as indicated in CFR 29 Part 1910, Section 1000. 2.3 Thermal Spraying 2.3.1 Safety Issues Airborne metal dusts and fumes, finely divided solids, or other particulate accumulations should be treated as explosive materials. Proper ventilation, good housekeeping, and safe working practices should be maintained to prevent the possibility of fire and explosion. Thermal spray equipment should never be pointed at personnel or flammable materials. Thermal spraying should not be performed in areas where paper, wood, oily rags, or cleaning solvents are present. Electrically conductive safety shoes should be worn in any work area where an explosion is a concern. During thermal spray operations, including the preparation and finishing processes, employees should wear approved protective coveralls or aprons, hand protection, eye protection, ear protection, and respiratory protection. SAFETY PRECAUTION: The fine aluminum and zinc particulates (metal dust and fume) produced during thermal spraying may be an extreme explosion hazard. Special precaution should be taken during wire-arc spraying due to the higher amounts of metal dust and fume produced that accompany higher spray rates, especially if multiple wire-arc spray units are being used in the same work area. Do not use water to extinguish aluminum or zinc fires. Use dry sand or a Class D extinguisher.
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6 2.3.2 Personal Protective Equipment The general requirements for the protection of personnel involved with thermal spraying are the same as those specified for welders in ANSI/AWS Z49.1, "Safety in Welding and Cutting." Helmets, hand shields, eye protection (face shields or goggles), hearing protection, respirators, and appropriate protective clothing shall be worn during all spraying operations. 188.8.131.52 Eye and skin protection. All thermal spray processes introduce particulates and fumes into the air that may irritate and damage the eyes or skin. The processes also emit hazardous ultraviolet (UV), infrared (IR) and intense visible light radiation. · Eye and face protection must be worn to protect against particulate impingement. Hoods or face shields conforming to ANSI Z87.1 and ANSI Z89.1 with filter lenses should be worn to protect the face and eyes. Various shades of lens filters are recommended based on the type of thermal spray process being used: For wire-flame spray, use lens shades 2 to 4. For wire-arc spray, use lens shades 9 to12. Shades 3 to 6 can be used for wire-arc spray if the gun is equipped with an arc shield. The shield encloses the arc and reduces the operator's exposure to the high-intensity light radiation. · Other workers in the vicinity of the thermal spray applicator should also use proper eye protection. · Flame-resistant clothing should be worn to protect the skin. Clothing should be strapped tightly around the wrists and ankles to prevent contact with sprayed materials. Open shirt collars and unbuttoned pocket flaps are unacceptable. High-top shoes should be worn, and cuff-less trousers should cover the shoe tops. Protection against radiation from the spray process is detailed in ANSI/AWS Z49.1. · Aluminized clothing may be used with the following precautions: IR and UV radiation are not to be reflected onto unprotected skin. Provide suitable protection against electric shock. 184.108.40.206 Hearing protection. Thermal spray produces very high noise levels (up to 130 dBA) that can rapidly cause permanent hearing loss. · Thermal spray operators and other workers in the vicinity of the thermal spray operation should wear approved hearing protection at all times. · Protection against the effects of noise exposure should be provided in accordance with the requirements of EM 385-1-1, Section 5, "Personal Protective and Safety Equipment," Subsection 05.C, "Hearing Protection and Noise Control," and CFR 29 Part 1910, Section 95. · Insert earplugs should be used during wire or powder flame spray. Insert earplugs should be worn as a minimum protection during wire-arc spraying. Insert earplugs and approved earmuffs are recommended for use with wire-arc, plasma, and high-velocity oxygen fuel
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7 (HVOF) spray. Table 1 lists the minimum recommended hearing protection devices for various thermal spray application methods. 220.127.116.11 Respiratory protection. Thermal spray generates toxic dusts and fumes. Thermal spray operators and personnel in the general vicinity of the spraying operation should wear appropriate approved respirators. Overexposure to zinc fume is known to produce flu-like symptoms, often called "metal fume fever." · An approved mechanical filter type respirator shall be used when spraying nontoxic materials with dust and metal-fume exposure. When spraying in confined spaces, an air- line respirator shall be used. When spraying highly toxic materials, the air-line respirator shall be equipped with an emergency auxiliary cylinder of respirable air. Respiratory protection shall be in accordance with ANSI Z88.2. · All respiratory devices used shall comply with the U.S. Bureau of Mines and the National Institute for Occupational Safety and Health (NIOSH). 2.3.3 Wire-Arc Spray 18.104.22.168 Electrical shock prevention. High DC voltages and amperages (currents) inherent to the wire-arc spray process pose severe electrical hazards. The operator shall be thoroughly trained in the safe operation of the wire-arc spray equipment prior to its use. · The manufacturer's safe operating procedures should always be followed. · Ground protection for equipment and cords should be present, in good condition, and tested regularly for correct operation. · Electrical outlets should have ground fault circuit interrupters (GFCIs) in addition to appropriate over-current protection (e.g., fuses and circuit breakers). Electrical circuit grounds and GFCIs should be tested before work begins and tagged, reported, and not used if found to be faulty. · Switches and receptacles should have proper covers. · Buttons, lights, plugs, and cables shall be in compliance with ANSI/NFPA 70, "National Electrical Code." Periodic inspections of cables, insulation, and hoses shall be performed. Damaged components shall be tagged, removed from service, and immediately repaired or replaced. · Cords should be approved for outdoor or wet or damp locations. The cords should be hard usage or extra hard usage as specified in ANSI/NFPA 70 "National Electrical Code." Cords should not be spliced. · Arc guns and power supplies should be cleaned frequently, as per the manufacturer's recommendations, to remove build-ups of metallic dusts, which may cause short circuits. TABLE 1 Typical noise levels and hearing protection requirements Thermal Spray Process Noise Level, dB(A) Minimum Recommended Protection Wire-flame spraying 114 Earplugs Wire-arc 111116 Earplugs and earmuffs
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8 2.3.4 Flame Spray 22.214.171.124 Gas cylinder safety. To ensure gas cylinder safety, the guidelines listed below should be followed. · Compressed gas cylinders should be handled in accordance with ANSI Z49.1 and with CGA P-1. · Only special oxidation-resistant lubricants should be used with oxygen equipment; grease or oil should not be used. · Manifolds, pressure-reducing regulators, flow meters, hoses, and hose connections should be installed in accordance with ANSI Z49.1. · A protective shield should be used to shield glass tube flowmeters from the spray gun. · Pressure connecting nuts should be tight, but not overly tight. Fittings that cannot be sealed without excessive force should be tagged and replaced. · Compressed air for thermal spraying or blasting operations should only be used at pressures recommended by the equipment manufacturers. The air-line should be free from oil and moisture. · Compressed air, oxygen, or fuel gas should never be used to clean clothing. · Cylinders should be handled, stored, and secured in accordance with established regulations and safe working practices. · Hoses used with flammable gases shall be fitted with approved "flash-back" arrestors to prevent any flame burning back along the hoses from reaching the cylinders. 126.96.36.199 Flame spray safety. To ensure flame spray safety, the guidelines listed below should be followed. · Flame spray equipment should always be maintained and operated according to the manufacturer's instructions. Thermal spray operators should be trained and familiar with their equipment before starting an operation. · Valves should be properly sealed and lubricated. · Friction lighters, pilot lights, or arc ignition methods of lighting flame spray guns should be used. · If the flame spray gun backfires, it should be extinguished immediately. Re-ignition of a gun that has backfired or blown out should not be attempted until the cause of the trouble has been determined and remedied. · Flame spray guns or hoses should not be hung on regulators or cylinder valves. Gas pressure should be released from the hoses after the equipment is shut down or when equipment will be left unattended. · Lubricating oil should not be allowed to enter the gas mixing chambers when cleaning flame spray guns. · Do not light wire-flame and rod guns without wire or rod in the nozzle as flames may burn back into the gun, causing operator injury and equipment damage. 2.3.5 Ventilation Thermal spraying should only be performed by operators using appropriate respiratory protection and in locations with adequate ventilation.
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9 · Local exhaust or general ventilation systems should be used to control toxic fumes, gases, or dusts in any operations not performed in the open. Thermal spraying in an enclosed space should be performed with general mechanical ventilation, air-line respirators, or local exhaust ventilation sufficient to reduce the fumes to safe limits specified by ACGIH-02. · Personnel exposures should be controlled to the safe levels recommended by ACGIH-02 or prescribed by CFR 29 Part 1910, whichever is the more stringent. · Air sampling should be performed before entry of personnel into a confined space, during confined-space entry that involves contaminant-generating operations such as flame spraying, and in areas where ventilation is inadequate to ensure that air contaminants will not accumulate. · Engineering controls (enclosures and/or hoods with ducted, mechanical ventilation of sufficient volume to remove contaminants from the work space) are the most desired methods of preventing job-related illness resulting from breathing air contaminated with harmful dusts, mists, fumes, vapors, and/or gases. · Treat airborne metal dusts, finely divided solids, or their accumulations, as explosives. Use adequate ventilation in the thermal spray work area and collect overspray to minimize the danger of dust explosions and fires. In shop environments, wet, bag, and dry filter-cartridge type collectors may be used to collect the fine overspray particles, thus minimizing the explosion and fire hazard and release of controlled and/or hazardous materials. Keep bag- and filter-cartridge collector units at least 50 ft (15 m) away from the spraying area to preclude ignition from the flame or heat of the thermal spray process. · Thermally sprayed aluminum and zinc powders, nominally 40 to 110 µm (0.0016 to 0.0044 in.) in diameter, are not a combustion or explosive hazard when handled and used in accordance with a powder manufacturer's instructions. Refer to the Aluminum Association's recommendations for the safe storage and handling of aluminum powders. · All fans, pipes, dust arrestors, and motors should be properly grounded. Ground to piping that carries fuel gases or oxygen should not be used. Ventilating fans should be kept running when cleaning out spray booths, pipes, etc., to prevent the accumulation of dust or fumes in the system. Aluminum and magnesium dusts present an explosive hazard that requires special attention. Adequate wet collector systems should be used with either of these metals. Care should be exercised, since these metallic dusts may generate hydrogen gas on contact with water. These systems should be designed to prevent hydrogen accumulation. Frequent, scheduled, cleanout operations should be performed to reduce residues. Residues should be handled and disposed of in accordance with OSHA and EPA regulations. 2.4 Housekeeping 2.4.1 Thermal Spraying Area Remove paper, wood, oily rags, cleaning solvents, sealers, and paints from the thermal spraying area. 2.4.2 Shop and Field Work Areas Good housekeeping in the shop and field work areas should always be maintained to ensure proper storage of hazardous materials and to avoid accumulation of combustible or
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10 potentially explosive materials and metal dusts, and particular attention should be given to inspecting for dust build-ups on beams, rafters, booth tops, and in floor cracks. 2.5 Sealers and Topcoats 2.5.1 Solvents Solvents used for cleaning or to apply sealers or topcoats (e.g., acetone, xylene, or alcohol) emit vapors that are harmful and can be fatal. · Use only with adequate ventilation or proper respiratory protection and other protective clothing as needed. · Avoid breathing solvent vapors and skin contact with solvents. · Most solvents are also flammable liquids. All solvent tanks must have lids and be covered when not in use. Take proper safety precautions. · Keep all solvents and flammable materials at least 50 ft (15.2 m) away from welding, oxyfuel cutting and heating, and thermal spraying operations. 2.5.2 Spray Application Sealers and paint coats are typically applied by spray application. Spray application is a high- production rate process that may rapidly introduce very large quantities of toxic solvents and vapors into the air. · Airless spray systems operate at very high pressures. Very high fluid pressures can result in penetration of the skin on contact with exposed flesh. · Tip guards and trigger locks should be used on all airless spray guns. The operator should never point the spray gun at any part of the body. · Pressure remains in the system even after the pump is turned off and can only be relieved by discharging or "blow-down" through the gun. 2.6 Material Safety Data Sheets (MSDSs) The contractor should maintain current MSDSs for all materials used on the job. These materials include cleaning solvents, compressed gases, thermal spray wires or powders, sealers, thinners, and paints or any other materials required to have an MSDS as specified in CFR 29 Part 1910, Section 1200. The MSDSs should be readily available to all personnel on the job site in a clearly labeled folder. 2.7 Environmental 2.7.1 Regulations Federal, state, and local regulations may be applicable with regard to containment, storage, and disposal of blasting debris and metallizing emissions. This may include partial or complete containment of the work site for surface preparation and thermal spraying and the collection and safe disposal of used blasting media and thermal spray overspray. Ensure compliance
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11 with the purchaser's requirements and all pertinent government agency requirements and regulations for air-quality and hazardous-materials control. 2.7.2 Handling Debris The applicator and the purchaser should coordinate the specific requirements, responsibilities, and actions for the containment, storage, collection, removal, and disposal of the debris produced by the TSMC operations. 2.7.3 Lead in Coating The removal of old coating containing lead requires special treatment. Further information is available in Chapter 11 of the U.S. Army Corps of Engineers Engineering and Design Manual, Painting: New Construction and Maintenance, EM 1110-2-3400, Washington, D.C., April 30, 1995.