Welding, Cutting, And Brazing

1. Welding, Cutting, And Brazing

2. Session Objectives • You will be able to: • Identify major safety and health hazards of welding • Select appropriate PPE for welding, cutting, and brazing • Implement controls to prevent or control fires

3. Types of Welding • Welding includes 60 or more process variations • Electric welding and oxy-fuel gas welding • Welding/cutting occurs at most businesses at some point

4. Welding Hazards • Fires—caused by unsafe welding or cutting operations • Burns • Electric Shock • Light radiation— ultraviolet, infrared, and intense visible light • Air Contaminants (gases, fumes, smoke)

5. Basic Fire Prevention • Inspect welding area before starting • Remove fire hazards • Install guards • Welding or cutting must NOT take place unless hazards removed or guards installed • Obtain a hot work permit before starting operations to ensure that all fire hazards are controlled • Post a fire watch person 1/2 hour after operation ceases

6. Fire Prevention (cont.) • Never weld in explosive atmospheres • Do not weld on used containers • Test potentially explosive containers for flammable atmospheres • Shut off cylinder valves when not in use

7. Ventilation • Three factors govern the amount of contamination to which welders may be exposed: • Dimensions of the space • Number of welders • Possible evolution of hazardous fumes • Management must ensure welders have proper protection and ventilation

8. Oxygen-Fuel Gas Welding • Acetylene • Flammable • Unstable • Cannot be used above 15 psi • Oxygen • Added to support fuel gas flame and obtain high temperature for melting steel (welding)

9. Basic Rules for Oxy-acetylene Welding • Ensure the safety fuse plug or disk is functional • Attach regulator • Stand to one side of regulator • Open cylinder valve slowly • Not more than 15 psi

10. Basic Rules for Oxy-acetylene Welding (cont.) • Purge oxygen and acetylene lines • Light the acetylene • Never use oil or grease near oxygen • Do not use oxygen to clean or blow off dirt or clothing • Keep your work area clean

11. Store Gas Cylinders Safely • The storage area must be well ventilated • Keep fuel cylinders 20 feet or more from combustibles • Close valves, ensure valves are protected • Limit inside storage to 2,000 cubic feet • Store cylinders in the upright position and secured from falling • Separate oxygen from fuel gas

12. Follow Gas Cylinder Precautions • Never lift cylinders by the service valve or valve protection (use slings, net, or other approved means) • Keys, handles, and hand wheels must be present • Use the proper regulator • Open acetylene valve no more than 11/2 turns • If in doubt about a cylinder, don’t use it

13. Use Protective Devices • Pressure relief valves, backflow preventers or check valves • Flash back arrestors • Fuel gas hose—red (sometimes black) • Oxygen hose—green • Hose protection required • Pressure-reducing regulators

14. Protect Yourself • Keep working surfaces clean and clear • Light torches with a striker, not a lighter! • Wear face and eye protection • Use safety glasses under welding hood and burning goggles with proper shading • Wear protective body clothing • Avoid synthetic clothing • Use leather gloves with gauntlet

15. Lens Shades • Generally, use a 4–5 shade for: • Torch brazing • Oxy-fuel gas cutting/welding

16. Oxy-Acetylene Welding—Any Questions? • Any questions about oxy-acetylene welding safety?

17. Arc Welding—Common Processes • Shielded metal arc welding (stick welding) • Gas metal arc welding (MIG welding) • Gas tungsten arc welding (TIG welding) • Flux cored arc welding • Submerged arc welding • Arc cutting • Plasma arc cutting

18. Arc Welding Hazards and Safety Measures • Hazards • Arc gives off ultraviolet and infrared rays the same as those causing sunburn • Exposure within several inches to a few feet can cause flash burn to eyes and skin • Safety measures • Avoid wet or damp areas—promotes electric shock hazard • Avoid oil, grease, and flammables as they pose a fire hazard

19. Shielding and Flash Screens • Air must be kept away from weld area • Shielding protects the integrity of the weld joint • Flux or gas mixture is used as a “shield” • Welders need to erect flash screens around them to protect others in area

20. Maintain Equipment Properly • Welding machines must be grounded • Work area must be dry and free of hazards • Connections must be tightly made • Cable splices within 10 feet of holder are prohibited • Cables must be maintained and conductors well insulated

21. Protect Yourself • Wear welding helmets with proper shading depending on type of arc • DO NOT use brazing goggles • Wear safety glasses under helmet • Wear leather gloves with gauntlets • Use ventilation or respirators • Wear leather bibs, sleeves, or jackets to prevent burns from slag, sparks, and ultraviolet

22. Lens Shades • Generally, use a 10–14 shade for: • Shielded metal arc • Gas metal arc • Gas tungsten arc

23. Arc Welding—Any Questions? • Any questions about arc welding?

24. Key Points to Remember • Major hazards include: • Fire • Burns • Shock • Toxic exposures • Follow proper procedures to prevent fires • Use appropriate engineering controls • Wear appropriate PPE