Fire, Injury Hazards
The welding process carries with it several fire and injury hazards that welding operators must recognize and minimize. The welding arc blows out sparks, particularly during carbon arc gouging. Welding also heats the workpiece, making the workpiece a potential cause of fire and burns. Similarly, arc rays produce intense invisible (ultraviolet and infrared) and visible rays that can burn eyes and skin. Any exposed skin can be burned quickly by these rays. Welding helmets should be fitted with a proper filter shade to protect the operator's face and eyes when welding or watching. Approved safety glasses with side shields should also be worn. Screens or barriers to protect others from flash and glare should be installed where appropriate and maintained.
To protect your body and clothing from flying sparks and heat sources, gloves and clothing should be flame-resistant. Clothing made from a dark-colored, tightly woven material is best suited for welding. Gauntlet type leather gloves should be worn to protect the hands and wrists. Button shirt collars, cuffs and front pockets to prevent them from catching sparks. Do not keep matches or butane lighters in your pockets. Avoid wearing cuffed pants, as the cuffs may catch sparks. Tennis shoes do not qualify as adequate foot protection; high-top leather shoes or boots provide the best foot protection.
|Proper safety gear and attire includes a welding helmet and gloves. Notice how the jeans pulled over the top of the work boots will prevent sparks from going down the boot top.
The intensely hot and powerful welding arc can quickly cut though gloves and skin. To prevent injury, do not grip material near the welding path.
The area surrounding the welder will be subjected to light, heat, smoke, sparks and fumes. Permanent booths or portable partitions can be used to contain these elements in one area. The heat and sparks can set flammable materials on fire. Therefore, welding should not be done in areas containing flammable gases, vapors, liquids or dusty locations where explosions are possible.
Metals with plating, coatings or paint that come near the arc region may give off smoke and fumes during welding. These fumes pose a health hazard to the lungs, therefore use an exhaust hood or booth to remove fumes from the area. When welding in confined spaces, such as inside tanks, large containers or even ship compartments, toxic fumes may accumulate. Also, in an enclosed room, shielding gases used for welding or purging can replace breathable oxygen. Take care to ensure enough clean breathing air. Many companies routinely provide welding operators with air masks or self-contained breathing equipment.
Because water conducts electricity very well, avoid wet working conditions (even body perspiration can lower the bodys resistance to electrical shock). Insulate yourself from work and ground by standing on a dry rubber mat or dry plywood sheet big enough to cover the full area of your contact with the work or ground. Be cautious, as both rubber and wood can ignite. If you can find a dry, non-flammable material to stand on (put between you and ground), use it.
Operators must routinely inspect for effective ground connections. Connect the workpiece to a proper earth ground. Connect the frames of all electrically powered machines to a properly grounded disconnect switch, receptacle or other appropriate ground. Always double-check the installation and verify proper grounding. Never use chains, wire ropes, cranes, hoists and elevators as grounding connectors.
When arc welding equipment is properly grounded according to the National Electrical Code, and to ANSI Z49.1 "Safety in Welding and Cutting" standards, a voltage may safely exist between the electrode and any conducting object. Examples of conducting objects include buildings, power tools, work benches, welding power source cases and workpieces. Never touch the electrode and any metal object unless the welding power source is off.
When using cylinders, securely chain them to a stationary, upright support or cart at all times. When moving or storing a cylinder, fasten the threaded protector cap to the top of the cylinder. This shields the valve system from impact damage.
|Make sure gas cylinders can’t fall over, such as by using a safe chain to secure them to a cart.
Also, welding guns and other cables should not be hung on or near cylinders. A gun could cause an arc against the cylinder wall or valve assembly, possibly resulting in a weakened cylinder or even a rupture.
Immediately remove a faulty regulator from service for repair. Do not attempt to repair a faulty regulator. Instead, send it to the manufacturer's designated repair center, where it will be repaired according to the manufacturer's specifications.
Use only recommended ferrules or clamps designed to connect hoses to fittings. Never use ordinary wire or other substitutes. Always suspend h oses off the ground to keep them from being run over, stepped on or otherwise damaged. Coil up excess hose to prevent kinks and tangles. Examine hose regularly for leaks, wear and loose connections. Immerse pressurized hose in water to check for leaks (bubbles will indicate leaks.) Repair a leaky or worn hose by cutting out damaged area and splicing. Do NOT use tape.
To arc weld metal safely, you must follow proper procedures to avoid accidents. Because this article does not cover all the safety issues that may exist, always refer to the operator's manual and ANSI Z49.1, "Safety in Welding, Cutting and Allied Processes," for a thorough explanation.
To maintain performance and safety levels, the following items require routine inspection:
Electrical components–Poor electrical connections can yield any number of problems and create excessive resistance that leads to difficult, or even impossible, arc starts. It can also lead to heating and unsafe operating conditions.
Power sources–Approximately every six months, disconnect the power to the unit and blow out or vacuum the inside of the machine. In heavy service conditions, monthly cleaning may be necessary.
Torches/guns–Torches, tips and nozzles should be kept in good working order and serviced at regular intervals. Turn off the power source and disconnect input power before disassembling the torch or changing torch parts. Use only the torches and consumables specified in the owner's manual.
Connectors–Join cable lengths with fully insulated lock-type connectors.
Cables–Frequently inspect cables for wear, cracks and damage. Immediately replace those with excessively worn or damaged insulation to avoid the possibility of lethal shock from bared cable. Keep all cables dry, free of oil and grease, and protected from mechanical damage (being run over or stepped on), hot metal and sparks.
Terminals and Other Exposed Parts–Secure covers over terminals and other exposed parts of electrical units before operation.
Electrical Safety Devices–Safety devices, such as interlocks and circuit breakers, should not be disconnected or shunted out. Before installation, inspection or service of equipment, disconnect all power by locking out and red-tagging switches or removing line fuses to prevent power from being turned on accidentally. Also, disconnect all cables from the plasma cutting source, and disconnect all 115 volt line-cord plugs.
Suggested Maintenance Schedule
Each Use–Check contact tip and nozzle. Check gas/air pressure.
Every 3 months–Replace unreadable labels. Service air filter/regulator assembly filter. Replace cracked parts. Tape torn outer covering or replace cable. Check gas/air hose. Check torch/gun body.
Every 6 months–(more often in harsh environments)Blow out or vacuum inside of power.
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