Slide Show Notes Welcome to the training session about welding, cutting, and brazing safety. The applicable OSHA regulations are located at 29 CFR

Transcription

1 Welcome to the training session about welding, cutting, and brazing safety. The applicable OSHA regulations are located at 29 CFR to 255 (Subpart Q) 1

2 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 2

3 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. 3

4 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. 4

5 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. 5

6 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. 6

7 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 7

8 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). 8

9 O 2 and Acetylene have different fittings and hose colors so they cannot be misconnected. Here are the basic rules to follow when working with Oxyacetylene 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 O 2, and 1 12 psi for acetylene, but never over 15 psi. 9

10 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 10

11 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. 11

12 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. 12

13 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 highpressure 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 13

14 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.). 14

15 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. 15

16 Are there any questions about the safety specifications or safe work practices for oxy acetylene welding? 16

17 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. 17

18 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 = 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 18

19 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. 19

20 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 20

21 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. 21

22 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 shade is used for: Shielded metal arc welding Gas metal arc welding Gas tungsten arc welding Show any welding helmets, glasses, or goggles that may be available. 22

23 Are there any questions about the safety specifications or safe work practices for arc welding? 23

24 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. 24