Subpart J: Welding and Cutting

1. Subpart J: Welding and Cutting Doris Kemp BCT 480

2. Welding • Welding joins two pieces of metal by the use of heat and/or pressure • 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 & Fumes • Generally, gases and fumes come from… • Base material & filler material • Coatings & paints • Shielding gases & chemical reactions • Process & consumables used • Contaminants in the air

5. Health Hazards…Gases & 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, fluorine compounds, carbon monoxide, cobalt, copper, lead, ozone, selenium, and zinc • cancer causing agents include: cadmium, nickel, beryllium, chromium, and arsenic

6. 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

7. Short-term exposures • Welding “smoke” can : • irritate the eyes, nose, chest and respiratory tract • cause coughing, wheezing, shortness of breath, bronchitis, pulmonary edema, and pneumonitis • cause nausea, loss of appetite, vomiting, cramps, and slow digestion

8. Long-term exposures • Studies of have shown that welders have an increased risk of lung cancer and, possibly, cancer of the larynx and urinary tract • Welders may experience a variety of chronic respiratory problems, including: • Bronchitis, asthma, pneumonia, emphysema, pneumoconiosis, decreased lung capacity, silicosis, and siderosis

9. Long-term exposures • Other health problems include: • Heart disease • skin diseases • hearing loss • chronic gastritis • ulcers of the stomach and small intestine • other reproductive risks

10. Other Health Hazards • Heat exposure • Heat stress, • heat stroke • Skin burns and skin cancer • Noise • Can result in stress, increased blood pressure, may contribute to heart disease, tiredness, nervousness, and irritability

11. Other Health Risks… • Eye damage- More than 5% of all eye injuries in the construction industry are associated with welding, cutting, and brazing • damage to retina • damage to cornea, resulting in cataracts • permanent eye damage • Invisible UV light can cause “arc eye” or “welders’ flash” • May include sandy or gritty eye, blurred vision, intense pain, tearing, burning and headache

12. 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

13. Engineering Controls and Work Practices • Use cadmium-free silver solders • Use asbestos- free electrodes, gloves, and hot pads • Use work area barriers to protect others working in the same general area

14. General Precautions • Construction personnel that is welding should be properly trained and qualified • Inspect work area for fire hazards before welding • Make provisions for ventilation before welding • Compressed gas cylinders should always be secured in an upright position when not in use and handled with extreme care

15. General Precautions • Gas cylinders should be stored at least 20 feet away from flammable materials and heat sources • Oxygen cylinders should be stored at least 20 feet away from gas cylinders and combustible materials. • When not possible, use a 5 ft tall noncombustible barrier with a 30 min. fire-resistance rating or better

16. General Precautions • All combustible materials should be removed from welding area or covered with noncombustible material, prior to welding • If covered, a worker that has experience using a fire extinguisher should be posted near as fire watch • Workers should stand to the rear or side of regulators when opening valves on tanks • Proper PPE should be worn, even by workers not welding

17. Other Precautions • Don’t weld on painted surfaces • Use water table to reduce noise • 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

18. 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

19. Protective Clothing • Fire resistant gauntlet gloves • Head cap • High top hard toed shoes • Leather apron • Face shield • Flame retardant clothing • Safety Glasses • Safety helmet • Hearing plugs and/or muffs

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 Precautions • 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 Precautions • 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

23. Dangerous Machinery • All machines in the area with moving parts must be guarded to prevent worker’s contact e.g. hair, clothing, fingers • When repairing machinery by brazing and welding, power must be disconnected, locked out, and tagged so the machinery cannot be started up accidentally

24. 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

25. 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 • Adequate ventilation must hold fumes and smoke to levels within the safe breathing range set forth in 29 CFR 1926 subpart D

26. Welding Hazards in Confined Space • No worker should work in an area with less than 19.5% or more than 23.5% oxygen content • Use continuous mechanical ventilation and proper respiratory protection • When adequate ventilation cannot be achieved, workers must be provided with air supplying respirators as described in 29 CFR 1926 Subpart E

27. 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 and remove when leaving for breaks, shift or crew changes • All pipes, ducts, and power lines that are not necessary for the work should be disconnected/locked out/tagged out

28. Gas welding Precautions • When transporting and handling, valve cap should be securely in place • Cylinders should never be lifted by valve cap • Cylinder valve should be closed when cylinder is empty, being moved or not in use • Cylinders should be secured to a pallet, cradle, or sling board for hoisting • Cylinders should not be dropped, bumped, struck or receive any other huge impact • Cylinders should be thawed with warm water when frozen in place

29. Gas welding Precautions • Fuel, gas and oxygen hoses must be easily and clearly distinguishable. • Oxygen and gas hoses must not be interchangeable • When oxygen and fuel hoses are taped, no more than 4 inches per foot of hose may be taped • Gas and oxygen hoses must be inspected before every shift and removed if defects are found. • Torches should be inspected before each shift to detect leaks • Tip openings should be kept clean and unclogged • Torches should be lighted by friction lighters

30. Arc welding Precautions • Only use manual electrode holders designed specifically for arc welding • All current-carrying parts should be properly insulated for maximum voltage encountered • Cables must be properly insulated, flexible and able to handle maximum current required • All equipment and cables should be inspected before each shift and should be removed if any defects are found • Operations should be shielded appropriately as to protect other workers in the area

31. Subject to damage • from other activities in • the vicinity Electrical cord in Contact with the cylinder Cylinder laying in a horizontal position. Compressed Gas Cylinder Safety

32. Chain Cylinders are not protected from falling. Note that the Chain is not secured across. Compressed Gas Cylinder Safety

33. Electrical Cord • 1. Cylinder not secured 2. Cylinder should be stored 3. Subject to damage. 4. Electrical cord draped over. Compressed Gas Cylinder Safety

34. 1. Small cylinder not tied off 2. Combustibles stored with cylinders 3. Bad housekeeping 4.Acetylene and Oxygen stored too close together and no chain. Compressed Gas Cylinder Safety

35. 1. Cylinder with no valve or cap installed 2. Laying horizontal on the ground 3. Subject to damage Compressed Gas Cylinder Safety

36. Electrical arc damage Cylinder is damaged. Should be taken out of service immediately! Compressed Gas Cylinder Safety

37. Cylinder should be in storage protected from damage and not laying on the ground regardless if it is full or empty Compressed Gas Cylinder Safety

38. Old, corroded cylinder that should have been disposed of a long time ago. Compressed Gas Cylinder Safety

39. Forklift 1. Cylinders laying on the ground and improperly stored 2. Subject to damage from forklift operation in vicinity Compressed Gas Cylinder Safety

40. 1. Feed line exposed to damage/leak that could cause a fire/explosion 2. Tripping Hazard Compressed Gas Cylinder Safety

41. 1. Inadequate housekeeping 2. Valve caps should be installed. Compressed Gas Cylinder Safety

42. Acetylene Cylinder • Unsecured acetylene cylinder 2. Exposed to damage Compressed Gas Cylinder Safety

43. Unsecured cylinders Compressed Gas Cylinder Safety

44. Regulator left pressurized after use Compressed Gas Cylinder Safety

45. Improper Storage Compressed Gas Cylinder Safety

46. Tie Off? Compressed Gas Cylinder Safety

47. Improper storage of cylinders- acetylene and oxygen stored next to each other Compressed Gas Cylinder Safety

48. Evidence of smoking next to acetylene cylinders Compressed Gas Cylinder Safety

49. This cylinder should be taken to storage and housekeeping should be improved. Compressed Gas Cylinder Safety

50. Unsecured cylinder Compressed Gas Cylinder Safety