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6 Welding Safety


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6 Welding Safety

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