September 13, 2006
By addressing six common hazards, companies that perform pipe and tube welding can provide a safe and healthy work environment for their employees.
Safety must be designed into the job, whether it's welding a 100-mile pipeline, repairing a 100-foot length of pipe, or fabricating a 100-millimeter tubular part. By failing to consider welding hazards, a company risks the safety and health of its employees, as well as the added financial stress of decreased productivity, increased absenteeism, and higher medical and insurance costs.
The majority of workplace injuries stem from six specific hazards: arc rays, arc sparks, welding fumes, electric shock, gas cylinder movement and storage, and employee trips and falls.
Arc rays produce intense, high-energy, visible, ultraviolet, and infrared rays that burn the eyes and skin, causing permanent damage, including blindness.
To protect workers from arc ray injuries, you must ensure that employees wear face shields with filters and cover plates approved by the American National Standards Institute (ANSI), as well as safety glasses underneath face shields or helmets, also ANSI-approved. Workers' heads must be kept a safe distance from the arc rays. Consider using "cheaters," magnifiers that help welders see better from a safer distance. Also be sure to provide Occupational Safety and Heath Administration- (OSHA-) specified welding screens, if needed, to help protect other workers near the welding action.
The required shade for face shields, filters, cover plates, and safety glasses varies with the intensity of the arc, which depends on amperage and the type of welding process employed. The darkened state brings its own risks by restricting vision. Make welders alert to the added hazards of slipping and falling while wearing darkened lenses. Autodarkening face shields help to address these challenges because they are easier to see through under normal light, but darken automatically when the arc ray is detected.
Another danger from the arc is spatter (hot metal) and sparks coming from the weld, which can burn skin and ignite clothing. Appropriate welding attire includes durable, oil-free clothing made of flame-resistant fabric, such as wool or heavy cotton, specifically rated for welding; leather aprons; leggings; shoes; capes or jackets; and dry, undamaged insulating welding gloves. Welders should avoid synthetic fibers, open shirt collars, open front pockets, and cuffs.
|Employers need to address the risks associated with arc sparks, spatter, and weld fumes to ensure worker safety.|
Welding and cutting processes generate fumes that can be hazardous if inhaled. The fumes comprise vaporized metal from rods, wires, coatings, and fluxes, as well as rust, mill scale, and coatings that may be on the surface of the metal. It is important to provide workers with proper protection from overexposure. The word overexposure means any exposure that may pose a health risk and which exceeds the permissible limits specified by OSHA, the American Conference of Governmental Industrial Hygienists (ACGIH), or other recognized authorities such as the National Institute for Occupational Safety and Health (NIOSH).
Different materials produce different fumes. Welding carbon steel can produce iron oxide and other particulates, and stainless steel can produce fumes with chromium and nickel. Welding also produces waste gases such as carbon monoxide, nitrogen dioxide, and ozone. Recently OSHA passed regulations to protect workers from chromium
VI fumes found in stainless steel welding that are deemed to be hazardous.
Welders must have proper ventilation and an approved respirator to protect them from fumes. The respirators should be comfortable and not hamper the use of other face-shielding equipment. Situations arise when standard air-purifying respirators alone will not guarantee an adequate supply of breathable air.
Welding operations in confined spaces with poor ventilation and air quality greatly increase the risk of inhaling toxic fumes. Therefore, it may be necessary to provide other forms of ventilation or even an air pack. Smoke extractors, such as hoods or "elephant trunk" suction devices placed near the work area, combined with the use of exhaust fans, are common means of removing fumes.
Assess each work area's air quality to determine ventilation needs. Exposure levels should be measured and compared with the permissible exposure limit (PEL) on the material safety data sheet (MSDS).
Most safety and welding equipment suppliers can recommend a reputable monitoring company for air quality analysis.
The welding process works on the flow of electricity with high amperage levels along a circuit. Inadvertently being exposed to this electrical flow may cause shock or even electrocution. In some situations, death can result from currents as low as 6 milliamps (mA), a fraction of the power most welding and cutting machines use.
Welding when wet increases the risk of shock, so workers should weld dry. This means not standing in water and using dry rubber mats or other insulating material. Welders should change clothing frequently and wear dry welding gloves to help eliminate perspiration, which can reduce the skin's resistance to electricity. They also should wear shoes with thick leather or rubber soles. At no time should they touch the electrode or welding wire with bare hands.
Make sure that equipment is maintained properly, and steer clear of cables that are too small, damaged, or poorly spliced. Cables should lie untangled and off to the side. Getting wrapped in electrical or welding cables increases the risk of electric shock and can prevent escape in the event of an emergency. Ensure the electric supply, equipment, and structure are properly grounded, and require employees to turn off all equipment when not in use.
The fifth safety hazard is the gas cylinder. All compressed-gas cylinders are considered hazardous simply because they are under as much as 2,500 pounds per square inch gauge (PSIG) of pressure. If damaged, the cylinder can explode, sending shrapnel flying. If the valve is damaged, the cylinder can take off like an unguided missile.
Handling cylinders requires special attention to safety. At 4.5 feet tall and 200 pounds, a falling cylinder can injure workers or result in a broken valve. Therefore, make sure employees who handle cylinders secure them properly at all times in a rack or with a chain.
Moving a cylinder safely requires these steps: Close the valve, remove the regulator, and replace the valve cap.
A cylinder never should be lifted by the valve cap, as the threads are not designed to handle the load. Slings or magnets should not be used to assist with a cylinder transfer. The proper way to move a cylinder is with a gas cylinder cart.
Most compressed gases also have properties that can be hazardous. Oxygen, for instance, can increase the risk of fire in high concentrations. Conversely, certain shielding gases, like argon or helium, displace oxygen, creating a higher risk of asphyxiation in an enclosed space. Fuel gases are highly flammable and require added safety precautions.
All workers handling cylinders should receive specific training on handling compressed gases. Here are a few of the rules to follow:
Finally, welding of pipelines, piping, and tubes often takes place in confined spaces, below ground, or even on raised platforms, increasing the risks for tripping and falling.
Workers should be aware of their surroundings, especially when working in confined spaces with limited mobility. They should make proper use of safety lines and rails and wear a safety harness when required. The welding area should be clear of debris, equipment, and cables. Machinery must have proper guards, potential obstacles must be limited as much as possible, and the work site must be kept free of grease and oil.
Most welding-related injuries are preventable by following proper safety procedures. Companies that build or repair pipelines, pipes, or tubes and tube and pipe fabricators need to make sure they have considered these safety tips before their next welding task.
Ultimately, providing a safe workplace where employees do their jobs effectively will result in a more productive work force. And that is no pipe dream.
Terry Byrd is a welding product manager for Airgas Inc., 259 N. Radnor-Chester Road, Suite 100, Radnor, PA 19087, 866-924-7427, www.airgas.com.
TPJ - The Tube & Pipe Journal® became the first magazine dedicated to serving the metal tube and pipe industry in 1990. Today, it remains the only North American publication devoted to this industry and it has become the most trusted source of information for tube and pipe professionals. Subscriptions are free to qualified tube and pipe professionals in North America.