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6 Welding Safety

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  • 1. Welding Safety
  • 2. Welding
    • Welding joins two pieces of metal by the use of heat, pressure, or both
    • Brazing or soldering involves a filler metal which has a lower melting point than the metal pieces to be joined
    • Metal cutting is done by heating the metal with a flame and directing a stream of pure oxygen along the line to be cut
  • 3. Welding
    • Arc Welding
    • Shielded Metal Arc Welding (SMAW)
    • Metal Inert Gas (MIG)
    • Tungsten Inert Gas (TIG)
    • Plaza Arc Welding (PAW)
    • Submerged Arc Welding (SAW)
    • And Many More…..more than 80 in all
  • 4. Health Hazards
    • Gases and Fumes…
    • Welding “Smoke” is a mixture of very fine particles called fumes and gases
    • Welding “Smoke” contains fumes and gases including…
    • Chromium, nickel, arsenic, asbestos, manganese, silica, beryllium, cadmium, nitrogen oxides, phosgene, acrolein, flourine compounds, carbon monoxide, cobalt, copper, lead, ozone, selenium, and zinc
  • 5. Health Hazards…Gases & Fumes
    • Generally, gases and fumes come from…
    • Base material & filler material
    • Coatings & paints
    • Shielding gases & chemical reactions
    • Process & consumables used
    • Contaminants in the air
  • 6. Health Hazards
    • It is difficult to list all the health effects of welding exposures because the fumes may contain so many different substances that are known to be harmful
    • The individual components of welding “smoke” can affect just about any part of the body, including the lungs, heart, kidneys, & central nervous system
  • 7. Health Hazards
    • Exposure to welding “smoke” may have…
    • Short-term effects…
      • Effects happen at or very soon after exposure
    • Long-term effects
      • Effects may happen after repeated overexposures or an extended time after the exposure
  • 8. Short-term exposures
    • Exposure to zinc, magnesium, copper and copper oxide can cause metal fume fever
    • Symptoms of metal fume fevere may occur 4 to 12 hours after exposure
    • Symptoms include…
    • Chills, thirst, fever, muscle ache, chest soreness, coughing, wheezing, fatigue, nausea, and metallic taste in mouth
  • 9. Short-term exposures
    • Welding “smoke” can irritate the eyes, nose, chest and respiratory tract
    • Welding “smoke” can cause coughing, wheezing, shortness of breath, bronchitis, pulmonary edema, and pneumontis
    • Welding “smoke” can cause nausea, loss of appetite, vomiting, cramps, and slow digestion
  • 10. Short-term exposures
    • Exposure to cadmium can be fatal in a short time
    • Ultraviolet radiation can react with oxygen and nitrogen to form ozone and nitrogen oxides
    • These gases are deadly at high concentrations and can also cause irritation of nose and throat and cause serious lung disease
  • 11. Short-term exposures
    • Ultraviolet rays given off by welding can react with hydrocarbon solvents such as…
    • Trichloroethylene; 1,1,1-trichloroethane; methylene chloride; & perchloroethylene to form phosgene gas
    • Even a very small amount of phosgene gas may be deadly
      • Early symptoms include dizziness, chills, and cough and usually take 5 – 6 hours to appear
  • 12. Short-term exposures
    • ARC welding should never be performed within 200 feet of degreasing equipment or solvents
  • 13. Long-term exposures
    • Studies of welders, flame cutters, and burners have shown that welders have an increased risk of lung cancer…
    • and…possibly cancer of the larnyx and urinary tract
    • Remember… welding “smoke” can include cancer causing agents such as…cadmium, nickel, beryllium, chromium, and arsenic
  • 14. Long-term exposures
    • Welders may experience a variety of chronic respiratory problems, including…
    • Bronchitis, asthma, pneumonia, emphysema, pneumoconiosis, decreased lung capacity, silicosis, and siderosis
  • 15. Long-term exposures
    • Other health problems…
    • Heart disease, skin diseases, hearing loss, chronic gastritis, gastroduodentis, and ulcers of the stomach and small intestine
    • Reproductive risks
  • 16. Other Health Risks…
    • Heat exposure…
      • Heat stress, heat stroke
    • burns, eye injuries from hot slag, metal chips, sparks, and hot electrodes
  • 17. Other Health Risks…
    • Visible light, and ultraviolet and infrared radiation
    • Intense light can cause damage to retina
    • Infrared radiation may damage the cornea and result in cataracts
    • Invisible UV light can cause “arc eye” or “welders’ flash”
      • May include sandy or gritty eye, blurred vision, intense pain, tearing, burning and headache
  • 18. Other Health Risks…
    • Permanent eye damage
    • Skin burns
    • Skin cancer
    • Noise
      • Can result in stress, increased blood pressure, may contribute to heart disease, tiredness, nervousness, and irratability
  • 19. Musculoskeletal Injuries
    • Back injuries, shoulder pain, tendonitis, reduced muscle strength, carpal tunnel syndrome, white finger, and knee joint diseases
    • Injuries may be caused by overhead work, vibration and heavy lifting
  • 20. Electrical Hazards
    • Even though welding generally uses low voltage, there is still a danger of electric shock
    • Wet work areas, Cramped work spaces
    • Falls, fractures and other accidents can result from electrical exposure
    • Even small shock can cause brain damage
    • Death can occur from large shocks
  • 21. Electrical Hazards
    • Always use dry gloves
    • Always wear rubber soled shoes
    • Always use insulating layers
    • Protect yourself from surfaces that conduct electricity
    • When working on electrically powered machinery, make sure the frame is grounded
    • Keep insulation on all welding equipment and components dry and in good condition
    • Don’t change electrodes with bare hands, wet gloves or while standing on wet or ungrounded surfaces
  • 22. Fire and Explosion Hazards
    • Intense heat and sparks can cause fires or explosions if in the vicinity of combustible or flammable materials
    • Welding and cutting should only be performed in areas free of combustible materials such as trash, wood, paper, textiles, plastics, chemicals, and flammable dusts, liquids and gases
  • 23. Fire and Explosion Hazards
    • Never weld or cut on containers that have held a flammable or combustible material unless the container is thoroughly cleaned or filled with an inert gas
    • A fire inspection should be performed prior to leaving a work area and for at least 30 minutes after the operation is completed
    • Fire extinguishers should be nearby, of proper size, type and number for the hazards involved
  • 24. Dangerous Machinery
    • All machines in the area with moving parts must be guarded to prevent worker’s contact
      • Hair, clothing, fingers, etc.
    • When repairing machinery by brazing and welding, power must be disconnected, locked out, and tagged so the machinery cannot be started up accidentently
  • 25. Trips and Falls
    • To prevent trips and falls…
    • keep work areas clear of equipment, machines, cables, and hoses
    • Always properly maintain and use handrails
    • Always use and maintain safety lines, harnesses and lanyards
    • Always make sure that scaffolds are properly assembled and used
  • 26. Welding Hazards in Confined Space
    • A work area with limited access, little or no airflow, not intended for continuous occupation
      • May also have dangerous atmospheres, hazardous configurations, or other hazards
    • All employees working in or around confined space must be trained
  • 27. Welding Hazards in Confined Space
    • Never weld or cut in explosive, flammable, combustible or other dangerous environments
    • Always use all necessary Personal Protective Equipment (PPE), including, harness and lanyard, respiratory protection, eye protection, etc.
    • Never work in confined space without a trained attendant
  • 28. Welding Hazards in Confined Space
    • Always leave gas cylinders and welding power sources outside the confined space…
    • Only take hoses or welding leads into confined space
    • Always removed hoses and/or leads when leaving confined space for breaks, shift or crew changes, etc.
  • 29. Welding Hazards in Confined Space
    • No worker should work in an area with less than 19.5% or more than 23.5% oxygen content
    • Never ventilate with oxygen
    • Use continuous mechanical ventilation and proper respiratory protection
    • All pipes, ducts, power lines, etc. that are not necessary for the work should be disconnected/locked out/tagged out
  • 30. Compressed Gas Hazards
    • Gas welding and cutting use a fuel gas and oxygen which are stored in high pressure cylinders
    • Most fuel gases are explosive
    • Pure oxygen will increase the flammability of any combustible/flammable material
  • 31. Compressed Gas Hazards
    • All cylinders should have caps or regulators
    • Pressure regulators must be designed for gas in use
    • Check all equipment and components prior to use
    • Cylinders must be stored upright and secured
    • Oxygen and fuel gas cylinders must be stored separately
    • Be aware of flashbacks and backfires??
    • Close cylinder valves when work is completed or left unattended during breaks, etc.
  • 32. Reducing Noise Hazards
    • Identify hazards and potential hazards prior to beginning hot work
    • Read the MSDS sheet to identify the hazardous material used in welding and cutting products, and the fumes that may be generated
    • Make sure that you know what you are welding before beginning
      • Cadmium exposure can be fatal in a very short time
  • 33. Compressed Gas Hazards
    • After a specific hazard(s) has been identified…
    • you can implement appropriate control method(s)
    • You can use appropriate PPE
  • 34. Engineering Controls and Work Practices
    • Substitute less hazardous materials for hazardous materials
    • Use cadmium-free silver solders
    • Use asbestos- free electrodes, gloves, and hot pads
    • Use ventilation to move away or dilute hazards
    • Use work area barriers to protect others working in the same general area
  • 35. Engineering Controls and Work Practices
    • Welding booths should be painted with dull finishes so they don’t reflect UV light
    • Acoustic shields between the worker and noise sources can reduce exposures
    • Noisy machinery can be totally enclosed
  • 36. Engineering Controls and Work Practices
    • Modify the process or follow safe work practices so that hazards are eliminated or reduced to the minimum…
    • Don’t weld on painted surfaces; use water table under plasma arc cutting to reduce noise; Grind instead of air-arcing; use sub arc; position yourself away from fumes; remove nearby flammables/combustibles; properly maintain equipment; proper housekeeping; use lowest possible amperage; hold electrode perpendicular and close to work surface
    • Never weld or cut within 200 feet of degreasing equipment or solvents
  • 37. Personal Protective Equipment (PPE)
    • PPE must be used in conjunction with engineering controls and safe work practices
      • Use of one does not eliminate the need for the other
    • Eye protection should be used in all welding operations
      • Wear face shields or helmets and goggles or safety glasses
    • Use appropriate filters on eye protection
  • 38. Filter Lens Shade Numbers
    • SMAW – 1/16 - 5/32 = #10
    • Gas SAW - 1/16 - 5/32 = #11 (nonferrous)
    • Gas SAW – 1/16 – 5/32 = #12 (ferrous)
    • SMAW – 3/16 – ¼ - = #12
    • 5/16 & 3/8 electrodes = #14
    • Atomic Hydrogen Welding = #10 - #14
    • Carbon Arc Welding CAW = #14
  • 39. Filter Lens Shade Numbers
    • Soldering = #2
    • Torch Brazing = #3 or #4
    • Light cutting up to 1 inch = #3 or #4
    • Medium cutting 1 inch to 6 inches = #4 or #5
    • Heavy cutting over 6 inches = #4 or #6
    • Light gas welding up to 1/8” = #4 or #5
    • Medium gas welding 1/8” to ½ “ = #5 or #6
    • Heavy Gas Welding over ½ “ = #6 or #8
  • 40. Protective Clothing
    • Fire resistant gauntlet gloves
    • Headcap
    • High top hard toed shoes
    • Leather apron
    • Faceshield
    • Flame retardant clothing
    • Safety Glasses
    • Safety helmet
  • 41. Hearing Protectors
    • Ear plugs and/or muffs should be worn during noisy operations such as air arcing or grinding
    • Most welding operations are noisy
  • 42. Respirators
    • Must be specific to the hazard
    • Must be fitted, cleaned, stored and maintained in accordance to regulation and manufacturers specs
    • NIOSH recommends respirators whenever a carcinogen is present

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