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Welding, cutting and brazing
- 1. Career Point University • • Submitted By - Nishant Sharma • Branch - Civil(3th year) • UID - K10621 •
- 2. © Business & Legal Reports, Inc. 0507 Brazzing Gas Cutting Spinning
- 4. © Business & Legal Reports, Inc. 0507 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
- 5. © Business & Legal Reports, Inc. 0507 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
- 6. © Business & Legal Reports, Inc. 0507 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)
- 7. © Business & Legal Reports, Inc. 0507 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
- 8. © Business & Legal Reports, Inc. 0507 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
- 9. © Business & Legal Reports, Inc. 0507 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
- 10. © Business & Legal Reports, Inc. 0507 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)
- 11. © Business & Legal Reports, Inc. 0507 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
- 12. © Business & Legal Reports, Inc. 0507 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
- 13. © Business & Legal Reports, Inc. 0507 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
- 14. © Business & Legal Reports, Inc. 0507 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
- 15. © Business & Legal Reports, Inc. 0507 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
- 16. © Business & Legal Reports, Inc. 0507 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
- 17. © Business & Legal Reports, Inc. 0507 Lens Shades Generally, use a 4–5 shade for: • Torch brazing • Oxy-fuel gas cutting/welding
- 18. © Business & Legal Reports, Inc. 0507 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
- 19. © Business & Legal Reports, Inc. 0507 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
- 20. © Business & Legal Reports, Inc. 0507 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
- 21. © Business & Legal Reports, Inc. 0507 • 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 Maintain Equipment Properly
- 22. © Business & Legal Reports, Inc. 0507 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
- 23. © Business & Legal Reports, Inc. 0507 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
Editor's Notes
- Slide Show Notes Welcome to the training session about welding, cutting, and brazing safety. The applicable OSHA regulations are located at 29 CFR 1910.251 to 255 (Subpart Q)
- Slide Show Notes By the end of the training session, 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
- Slide Show Notes Welding is a general term that describes 60 or more processes that use heat to fuse metals together. The processes include electric “arc” welding as well as oxygen or “oxy” – fuel gas cutting or welding. Cutting or welding occurs at most business at one time or another as part of construction, maintenance, or repairs. Welding is part of the core business for some industries such as metal fabrication. Discuss the types of welding done at your facility. Modify this slide to describe the specific types of welding at your facility.
- Slide Show Notes About 6% of industrial fires causing loss of human life are due to unsafe welding or cutting operations. Such fires start when sparks from small pieces of molten metal or slag (larger pieces of molten metal) come in contact with flammable or combustible materials. Burns to the body. Electric shock and burns from electric (arc) welding. Radiation: ultraviolet causes flash burns; infrared causes heat burns, irritation; intense visible light causes headache and eye strain. Air Contaminants: Combustion gases, material – metallic oxides, mineral dusts, toxic fumes. Ask the participants to discuss specific incidents that have happened at your facility or in your industry.
- Slide Show Notes Inspect the welding area before operations begin to eliminate possible fire sources. It is best to perform welding in a designated area when possible to avoid additional hazards, otherwise remove fire exposures from the immediate area if possible. If the fire hazard cannot be removed, guards must be installed If fire hazards are not removed, or guards are not installed, the welding or cutting operation must not take place. Be sure to obtain a hot work permit before performing any welding jobs. This will help ensure that all hazards are controlled. Someone must also be posted as a fire watch from the time welding begins to at least 1/2 hour after the job is done.
- Slide Show Notes Here are fire prevention techniques associated with welding. Never weld in the presence of explosive atmospheres. Do not weld on used drums, barrels, tanks, or other containers. Test potentially explosive containers for flammable atmospheres. Shut off cylinder valves when they are not in use. It may be necessary to use special techniques such as inerting the space inside a container to eliminate flammable/explosive vapors prior to welding or cutting.
- Slide Show Notes 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 is responsible for ensuring welders have proper protection and ventilation
- Slide Show Notes The primary fuel gases for welding, cutting, and brazing operations are: Acetylene, which is flammable, unstable, and cannot be used above 15 pounds per square inch (psi). Oxygen Added to support fuel gas flame and obtain high temperature for melting steel (welding).
- Slide Show Notes O2 and Acetylene have different fittings and hose colors so they cannot be misconnected. Here are the basic rules to follow when working with Oxy-acetylene gas-fueled systems: Compressed gas cylinders must have a safety fuse plug or disk; check it to make sure it is functioning. Never use oxygen or fuel gases directly from the cylinder; there must be a regulator attached to the valve. Stand to one side of regulator to avoid injury if it malfunctions. Open the cylinder valve slowly. Use 3-7 psi for O2, and 1-12 psi for acetylene, but never over 15 psi.
- Slide Show Notes Purge oxygen and acetylene lines Light the acetylene Don’t mix oxygen with grease or oil Mixture can cause spontaneous combustion and fire. Remember that oxygen and most other gases are stored under high pressure (2200 psi). Do not use oxygen to clean or blow off dirt or clothing because it dramatically increases the combustibility of the material Keep work area clean so as not to introduce unnecessary fire hazards
- Slide Show Notes Storage area must be well ventilated Fuel cylinders must be at least 20 feet from combustibles Valves must be closed. Regulators should only be on cylinders in use, not on those that are stored. Valve protection must be in place. Valve protection caps are designed to take a blow should the cylinder fall, thus preventing the cylinder from impersonating a rocket. Inside storage must be limited to 2,000 cubic feet Cylinders must be stored in upright position and secured from falling. Never lay the cylinder down; store it upright, and always secure it during storage Oxygen storage. Keep fuel gas and oxygen separated by at least 20 feet, or keep separated by a 5-foot-high barrier with at least a half-hour fire rating.
- Slide Show Notes Handling cylinders properly is important because of the extreme pressure contained in each cylinder. Use these precautions at all times. 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 you are uncomfortable with the way a cylinder looks, don’t use it.
- Slide Show Notes Make sure that a system that has been approved for use remains intact, and that approved regulators have not been substituted with other regulators such as high-pressure regulators.The following types of safety devices are important to prevent potential fires and/or explosions: Pressure relief valves, and backflow preventers or check valves Flash back arrestors Fuel gas hose—red (sometimes black) Oxygen hose—green Hose protection required Pressure-reducing regulators
- Slide Show Notes Keep working surfaces clean and unobstructed. Light torches with a striker. Do not use butane lighters. Welders have been killed by slag or sparks hitting a lighter in their pocket and causing an explosion. Wear eye protection Use safety glasses under welding hood and burning goggles with proper shading to protect against ultraviolet and infrared exposure. Face and eye protection is imperative to avoid possible welder’s flash, which can permanently damage your eyesight. Protective clothing must be worn during welding, cutting, and brazing operations. Avoid synthetic clothing – synthetic clothing melts readily. Wear cotton or wool. Wear leather gloves w/gauntlet. Show samples of personal protective equipment for use while welding (i.e., helmets, gloves, aprons, etc.).
- Slide Show Notes Because the shades vary for the different types of welding, it is important that routine inspections be conducted to ensure that the proper shades are used on the various welding operations. Check the manufacturer or OSHA charts for specific welding applications. Generally a 4 – 5 shade is used for: Torch brazing Oxy-fuel gas cutting/welding Show welding helmets, glasses, or goggles.
- Slide Show Notes The following are the various types of arc welding processes. Shielded metal arc welding (stick welding) Gas metal arc welding (MIG welding) Gas tungsten arc welding (TIG welding). Arc welding such as TIG and MIG use a shielding gas. Flux cored arc welding Submerged arc welding Arc cutting Plasma arc cutting Modify this slide to describe the arc welding process(es) at your facility.
- Slide Show Notes Arc welding is very common. A high percentage of industrial welding is arc or “stick” welding. Electric current fuses parent metal and welding rod. The typical electrical current = 50-30 amps at up to 80 volts. Arc welding is indispensable in metal working. It is used for carbon and alloy steels and nonferrous metals. The safety hazards of arc welding are: 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 for avoiding hazards of arc welding include: Avoid wet or damp areas – promotes electric shock hazard Avoid oil, grease and flammables as they pose a fire hazard
- Slide Show Notes Air must be kept away from the weld area so as not to introduce contaminants. Shielding protects the integrity of the weld joint. Shielded gas welding uses an inert gas to keep air away from the weld area and protect the integrity of the weld. Using flash screens protects others in the area from the flash associated with welding.
- Slide Show Notes Follow these straightforward rules for the safe maintenance of welding equipment. Welding machines must be grounded Work area must be dry and free of hazards Connections must be tightly made Cable splices cannot be within 10 feet of holder Cables must be maintained and conductors must be well insulated
- Slide Show Notes Here are some procedures to follow in order to protect yourselves from injury. 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.
- Slide Show Notes All types of welding processes used today involve high heat and potential for fires, burns and other hazards. Know the hazards in your area. Some of these hazards include: Fire Burns Shock Toxic exposures to fumes, gases and vapors. Follow proper procedures to prevent fires. Use appropriate engineering controls such as ventilation, shields and screens to protect you or others in the area. Wear appropriate PPE such as gloves, safety glasses, helmets, and aprons.