Worker Safety: Safe Practices for Welding
Welder's face a combination of safety and health risks.
Welding, cutting, and brazing have become commonplace activities in the general industrial, construction, shipping, and agricultural sectors. More than 500,000 workers in a variety of industries provide welding, cutting, and brazing services. Those employees face a combination of safety and health risks. In terms of statistics, approximately four deaths per thousand workers occur over a working lifetime. Risks involved with welding, cutting, and brazing include noise, arc rays, electric shock, burns, fire and explosion, and fumes and gases. The risks amplify when welding within confined areas.
Welding equipment and welding operations create noise that can cause gradual hearing loss over time. The length and number of times that exposure to high levels of noise translates into the amount of damage to hearing. Ear protection and sound shields protect workers from high noise exposure levels of 85 decibels and the resulting discomfort and hearing loss.
Welding can cause exposure to arc rays and ultraviolet radiation which—in turn—can cause a condition called “welder’s flash.” With this condition, an individual may experience swelling, fluid excretion, and temporary blindness. Repeated or prolonged exposure to UV radiation can cause permanent eye damage. In addition, UV radiation takes the form of heat and can also burn skin.
Helmets and hand-held face shields protect against arc radiation. The shields consist of hard plastic or fiberglass and protect against Using the proper shade lens on a welding helmet stands as the first line of defense against arc rays. Safety glasses with side shields or goggles offer good protection against any flying debris. Manufacturers advise to select a filter that completely blocks the arc.
Welding includes many hazards. However, the chances for electric shock present a very high risk for any welder because simply using the power switch to turn off the welder does not turn off power inside the welder. Disconnecting the input power cord or turning the power disconnect switch off turns off the power inside the welder. Even with those disconnects in place, never remove fixed panels from the welder.
Arc welding has two different types of potential shock hazards. Primary voltage shock that ranges from 230 VAC to 460 VAC may occur if a welder touches a lead inside the welder while the body touches the welder case or grounded metal. Secondary voltage shock ranges from 20 VAC to 100 VAC and occurs if a welder touches part of the electrically “hot” electrode circuit while the body touches the work surface metal. Preventing secondary shock involves wearing dry gloves, keeping dry insulation between the body and any metal, and regularly checking the welding cable and electrode holder for damage. Always replace the holder and the electrode cable if damage has occurred.
To ensure that the welder matches the welder supply, only qualified electricians should install a welder. Since the primary voltage supplies power for the welder, the input to the welder must match the phase voltage required for operation. The case must connect to earth ground so that any internal electrical problem will cause a fuse to blow and disconnect the power.
A welding arc can reach a temperature of 10,000oF and can burn skin and eyes within a few minutes. To protect against possible burn conditions, welders must wear protective clothing. Workers should avoid rolling up sleeves or pant-cuffs so that sparks or hot metal will not land in folds. Personal protective equipment should include flame-resistant suits, aprons, leggings, high-top boots with steel toes, and heavy, flame-resistant gloves.
FIRE and EXPLOSION
The intense heat caused by welding can result in sparks or molten metals that sometimes spray as far as 35 feet from the work area. Those sparks and metals can fall into liquid, solid, or gaseous combustible materials that ignite when heated. Use fire-resistant shields to prevent the spray and—when possible—move combustibles away from the work area. Take particular care to avoid dust explosions when welding or cutting in a dusty area. Secure gas cylinders away from combustibles and fuels while safeguarding the cylinders from heat and flames. Always inspect the work area for any flammable coatings or materials and always verify the presence of fire alarms and access to fire extinguishers, sand buckets, and fire-resistant blankets.
FUMES and GASES
Welding and cutting some materials may release toxic fumes and gases. While the short-term exposure to fumes and gases can cause temporary symptoms of burning eyes and skin, dizziness, nausea, and fever, the long-term exposure may cause iron deposits to form in the lungs and result in bronchitis or lung fibrosis.
Adequate ventilation of work areas can occur through several different types of systems. Low vacuum/high volume ventilation systems move 560 and 860 cubic feet of air per minute while using low vacuum levels. High vacuum/low volume ventilation systems provide a solution for close proximity positioning and have low air flow rates. Source extraction filtration equipment captures and extracts weld fumes from the source and pas the fumes through a cartridge or filter.
TAKING THE INFORMATION HOME
Applying sufficient safety measures can dramatically decrease exposure to hazardous conditions. OSHA and ANSI standards provide detailed information about safety measures. The ANSI Z49.1 bulletin titled “Safety in Welding and Cutting” provides a thorough list of safety practices.