Best Practices 101
The misconception of welding's being a dangerous occupation is largely due to welders who made careless mistakes by not being aware of or not following the recommended safety procedures and protocols.
- By Bill Gardner, Al Hilbert
- Aug 01, 2010
Sometimes perceived as hazardous, welding actually presents relatively few hazards to the welder or co-workers if done according to the proper procedures and recommended safety precautions. The key to minimizing potential hazards lies in first understanding them and then taking the necessary steps to mitigate them.
Following is a discussion of four of the most common sources of danger in a welding environment -- heat, sparks and spatter, ultraviolet radiation, and fumes -- and the recommended ways to avoid them.
The combination of several sources of heat within a welding application can lead to significant health and safety risks to the welder. Among these risks are heat stroke, heat exhaustion, fainting, and a reduced ability to identify and respond to other dangers in an industrial environment.
Radiant heat from the welding arc, which can reach 6,500 degrees F, and the base metal, which absorbs and conducts heat outward from the welding arc, can increase the ambient temperature in the immediate vicinity to a temperature that would be uncomfortable even for someone wearing a short-sleeved shirt and shorts.
Avoiding some of the other hazards of welding, however, requires head-to-toe protective apparel that can weigh up to 10 pounds and can prevent the body from releasing its heat into the environment.
Further compounding the dangers of heat stress within the weld cell is the fact that the majority of industrial welding applications use shielding gas to protect the weld puddle from contamination by the air atmosphere. Winds over 5 mph will blow away the shielding gas, resulting in weakened welds, eliminating the possibility of using localized fans to aid in cooling.
Employers can take a number of steps to evaluate heat stress within the welding cell and reduce the potential for heat-induced injury and illness. A formal heat stress control plan, consisting of a mixture of engineering and administrative controls, along with PPE, is considered a best practice for mitigating heat stress.
A number of PPE options are available to shield an employee from heat and allow their bodies to more easily dissipate heat. Under-hood air circulators can direct air over the welder's head and face to reduce the under-hood temperature. Other protective equipment options include a water-cooled vest and "breathable" welding jackets.
Certain compounds found in welding fumes, including hexavalent chromium, have employee exposure limits mandated by OSHA and other governmental organizations.
In the case of hexavalent chromium -- [CR(VI)], which is produced during the welding of metals that contain chromium, including stainless steel -- the Permissible Exposure Limit (PEL) over the course of an 8-hour work day is 5 µg/m3, with an Action Level of 2.5 µg/m3.
The welding process, wire type, base metal, and a variety of other factors will affect the amount of fumes produced in the welding application, so employers will need to determine whether or not their employee's welding fume exposure falls within regulatory compliance. In situations where fume exposure exceeds federal or state standards, there are a number of fume control methods that are available to meet the needs of most welding applications.
According to OSHA, engineering controls with source capture are the preferred method of reducing the amount of fumes in a workplace. For some companies, however, large-scale engineering controls are not feasible. In these cases, there are smaller source capture fume extraction models that can be used to extract and remove fume particles at their "source." Source capture extractors vary greatly in terms of the applications for which they are designed, as well as their ability to effectively and efficiently remove fume particles from the weld cell. Because welding fumes are between .3 and 1 micron in size -- much smaller than the particle that most "air filters" are designed to collect -- it's important to select a fume extractor with a filter constructed specifically for welding fumes.
In addition to the particle size that a filter captures, companies should consider how often the filter will need to be cleaned or replaced and how much employee downtime is required when cleaning or replacement is necessary. Surface-loading filters, which trap fume particles on the surface of the filter, tend to require less frequent replacement and less pressure drop than depth-loading filters, which trap particles throughout the filter material.
In some applications, a source capture device might also not be feasible or may not capture enough fumes to reduce the exposure to acceptable levels. In these situations, a Powered Air Purifying Respirator is often an effective solution for shielding an employee from welding fumes. It typically contains a belt-mounted filter and battery-powered fan that blows filtered air into the welding helmet, thereby expelling welding fumes from the air the welder is breathing. PAPRs are particularly useful in applications where the welder needs to continually walk around or climb on large objects, such as trailer manufacturing.
Beyond the need to simply comply with federal and state fume exposure requirements, however, many companies have found that fume extractors create a more pleasant and enjoyable work environment that improves their ability to attract and retain talented welders.
Sparks and Spatter
Sparks and spatter can cause severe burns to exposed skin and are one of the primary reasons that head-to-toe protection is required.
When selecting the right safety equipment to protect against burns from sparks and spatter, it is important to take into account not only the variables present in the welding application, but also the comfort of the welder. Welders often spend their entire shift wearing their protective apparel, and the potential for burns or other injuries increases if the welder's apparel is uncomfortable and he takes it off every chance he gets.
The welding process, welding wire, shielding gas, application, and technique all can have a significant impact on the amount of sparks and spatter produced. Recognizing those differences and their respective apparel needs, many companies now offer safety apparel that is tailored to the specific protection and comfort needs of the various processes and applications.
As an example, welding gloves are now designed for specific welding applications, such as MIG, TIG or Stick welding, and strike a balance between providing the necessary protection for those processes and remaining as light in weight and comfortable as possible. Likewise, welders now have a number of choices when selecting their welding jacket and leg protection. In heavy-duty applications where heat stress isn't a concern, welders can select a full leather jacket with a leather bib for leg protection. At the opposite end of the spectrum, lightweight and "breathable" jackets provide adequate protection and durability for light-duty applications and where heat stress is a concern.
Regardless of the brand selected, the welding jacket and pants should be made of flame-resistant materials (synthetic materials, such as polyester, can melt and stick to the skin, amplifying the severity of a burn) and not contain cuffs or other folds into which a piece of hot spatter can become lodged. Also recommended are leather boots that are at least ankle-high, a skull cap to protect the top and back of the welder's head, and a welding helmet that protects the welder's neck and head.
Anyone who has ever experienced "arc flash" or gotten a "welder's tan" will readily spread the gospel about the dangers of ultraviolet (UV) radiation and the benefits of good protective apparel. UV rays from the welding arc can burn the skin and eyes in a matter of seconds.
In the case of the eyes, UV radiation can lead to extreme dryness, discomfort, and pain that can persist for several days. Although temporary in all but the most extreme cases, arc flash of the eyes can interfere with a welder's ability to successfully perform his job.
Auto-darkening welding helmets offer an effective way to reduce the occurrence of accidental arc flash to the welder's eyes by providing continuous UV protection even when the helmet's lens is in its "non-darkened" state. In this way, welders can keep their helmets down while grinding or otherwise preparing the metal to be welded without risking exposure from nearby welding cells or from accidentally striking an arc before he is ready. Auto-darkening helmets use liquid crystal display technology to darken within 1/20,000 of a second (.05 milliseconds), or roughly 2,000 times faster than the blink of an eye.
As an added benefit, auto-darkening helmets also can lessen the stress placed on the welder's neck caused by repeatedly flipping the helmet up and down between welds.
UV rays also have the ability to burn the welder's skin, causing symptoms identical to sunburn, including redness, pain, and, eventually, peeling.
All PPE designed for welding applications will protect a welder from exposure to UV rays. The danger for many welders lies in not wearing complete protection when heat stress is a concern or when not wearing protective apparel when near others' welding arcs.
Too Many Careless Mistakes
The misconception of welding's being a dangerous occupation is largely due to welders who made careless mistakes by not being aware of or not following the recommended safety procedures and protocols. Before their first arc is struck, a welder should be equipped with the proper safety gear and be trained in the safe operation of the welding equipment. By understanding the potential dangers involved, as well as the right ways to avoid these hazards, welders and their employers can successfully reduce or eliminate lost-time incidents.
This article originally appeared in the August 2010 issue of Occupational Health & Safety.
Bill Gardner is Product Manager, Safety Apparel, for Miller Electric Mfg. Co., which has its headquarters in Appleton, Wis. The company is a leading worldwide manufacturer of Miller brand arc welding equipment and is a wholly owned subsidiary of Illinois Tool Works Inc. For more information, visit Miller's website at www.MillerWelds.com, call 1-800-4-A-Miller (800-426-4553), e-mail firstname.lastname@example.org, fax 877-327-8132, or write to Miller Electric Mfg. Co., P.O. Box 100, Lithonia, GA 30058.
Al Hilbert is Product Manager, Fume Extraction, for Miller Electric Mfg. Co., which has its headquarters in Appleton, Wis. The company is a leading worldwide manufacturer of Miller brand arc welding equipment and is a wholly owned subsidiary of Illinois Tool Works Inc. For more information, visit Miller's website at www.MillerWelds.com, call 1-800-4-A-Miller (800-426-4553), e-mail email@example.com, fax 877-327-8132, or write to Miller Electric Mfg. Co., P.O. Box 100, Lithonia, GA 30058.