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Manufacturing operations understand that protecting employees against weld fumes is critical to providing a safe working environment . And it’s also an issue of staying compliant with regulations.
What manufacturers may not realize is that some weld fume management solutions can also help significantly improve productivity. Therefore, it’s important to consider which option can help save the most time and money in your operation.
In the United States, the first line of worker protection is the Occupational Safety and Health Administration (OSHA). This federal agency is responsible for setting and enforcing exposure limit standards, as well as providing training, outreach, and assistance. Another great resource is the American Conference of Governmental Industrial Hygienists (ACGIH®), a member-based organization that develops recommendations at a deeper level of assistance in the control of occupational health hazards.
When choosing a weld fume management solution, consider these key factors:
- The welding process used or being implemented
- The type of filler metal and consumables used
- The condition of all materials in the upstream process
It’s important to consider all steps involved in the welding operation before making any changes or implementing new solutions.
Not all welding processes or filler metals are the same; some produce more weld fumes than others. To ensure success with the chosen solution, you must first know what types of weld fumes you’re producing.
Becoming familiar with OSHA’s Hierarchy of Controls is also key. The hierarchy outlines the steps employers can take to comply with environmental regulations and improve workplace safety. Before trying the following steps, first conduct air sampling within the facility with the help of a certified industrial hygienist or safety professional. Air sampling identifies the type and concentration of contaminants present in the facility.
Step 1: Process modification or substitution
The parts and types of materials in the upstream process can vary greatly — as can the condition of those parts. Always consider what your operation can do upstream to minimize or eliminate the source of weld fumes later. Sourcing clean materials or cleaning parts before the welding process can help.
A change to the welding process, consumables or filler metal can also help reduce the amount and type of weld fumes produced. Options include switching from stick to MIG welding or from self-shielding wire to solid wire to reduce fume generation. Anytime you can improve the weld process by reducing spatter and stabilizing the weld puddle, you’ll reduce overall fume generation. Operations can also reduce spatter and fume generation by using higher end processes that offer advanced puddle control and stability in combination with mixed shielding gases that provide higher argon content.
Substituting alternate materials or filler metal consumables is another approach to consider. Filler metal products with low-manganese content can reduce manganese fume emissions, and when combined with processes such as advanced pulsed MIG welding may result in a 60 percent reduction of manganese in fumes compared to standard filler metal fume emissions.
Note that these modifications may require recertification of welding procedures or additional training and testing costs.
Step 2: Engineering controls
If you can’t eliminate or significantly reduce fume through process modifications, the next step is to consider implementing engineering controls. These include process enclosure, general ventilation or source capture, and may require a physical change to the workspace.
- General (ambient) ventilation includes using the building’s HVAC system or high-powered fans to move large quantities of air to dilute weld fumes with fresh air on a predetermined air exchange rate. While considered easier to implement than source capture, this solution circulates air within the space rather than capturing fumes. Ambient solutions do have their place, such as when operators weld on large workpieces, making it impractical to move a source capture arm each time he or she changes position. In this case, pair a ventilation system with the proper personal protective equipment (PPE).
- Process enclosure is another option in some applications, such as robotic welding. This solution uses an enclosure to create a barrier between the process and the operator, containing the fumes within the weld cell. However, not all robotic welding applications eliminate exposure during part changes. The operator must wear proper PPE if air sampling determines it’s necessary. This option can eliminate the issue of weld fumes for other workers outside of the cell.
- Source capture through fume extraction is the best solution when considering the scale of good, better, best in engineering controls. Capturing fume at the source before it reaches the worker’s breathing zone should be the goal in every facility. Source capture options include weld fume extraction MIG guns, hoods and arms, which are both available in portable and stationary models.
Some source capture solutions are difficult to position over large weldments or other obstructions within the weld cell or fixturing, which can be a disadvantage. In addition, welding operators working on large weldments may not want to frequently reposition a source capture arm as needed.
In these cases, a fume extraction MIG gun may be the answer. These MIG guns use a fume chamber above the nozzle connected to a high vacuum system to capture welding fumes very close to the source — before they reach the operator. Keep in mind that fume extraction MIG guns are best suited for flat, in-position welding.
Typically, extraction systems with standard source capture fume arms capture weld fumes at a distance equal to the hood’s diameter over the weldment. When considering options, look for one with technology that creates a much larger capture area and minimizes arm interactions. This reduces or eliminates how often the operator must adjust or move the arm — saving time and improving productivity.
Overhead capture hoods are another option. Overhead hoods can be as small as 4 feet by 4 feet or as large as 16 feet by 16 feet. They are placed above the work area and connect to ductwork and a larger centralized fume extraction system. Hoods with a low profile are designed to minimize the space they require. Hoods can typically cover more area for fume capture than arms.
Step 3: Work practice (administrative) controls
The next step is to implement work practice controls. These do not remove hazards but instead limit or prevent an operator’s exposure to weld fumes by modifying behavior or the work environment. This step often involves proper operator training or modification of jigs and fixtures to allow for more ergonomic body positions in relation to the weldment and work habits to limit fume exposure. Even small adjustments can significantly reduce exposure rates and greatly improve productivity by helping the operator be more efficient.
A welding operator should use basic best practices, including keeping their head out of the weld plume; changing body position to take advantage of airflows moving from back to front; and making sure any air movement in the work area pushes fume away from the breathing zone.
Choose welding helmets that offer a larger, clear view of the weld puddle. These allow operators to keep their heads out of the weld plume — while maintaining a clear view of their work. Combined with regular vision testing, better helmets provide welders with more options for positioning — resulting in higher-quality work.
Step 4: PPE
The final step includes implementing respiratory protection. Options include disposable masks, half masks, powered air purifying respirators (PAPRs) or supplied air respirators (SARs). In some applications, PPE may be the only viable solution that reduces weld fume exposure below required levels. However, there are additional steps and expenses necessary with this solution, including medical evaluations, fit tests, training and filter replacements.
Use respirators if engineering controls are not feasible or do not reduce fume exposure levels enough, or during maintenance or emergency situations. Whether respirator use is mandatory or voluntary, companies must establish and maintain a written respiratory protection program as stated by OSHA 29 CFR 1910.134.
Each type of respirator is given an assigned protection factor (APF), which is the level of protection it will provide when used properly, in conjunction with a written respiratory protection program. Companies must consider the respirator’s APF, air-sampling results within the facility, and OSHA’s Permissible Exposure Limits (PELs) for those contaminants to determine which respirator is suitable. To get the most out of the respiratory protection, ensure each employee has selected a respirator that provides a comfortable fit and does not negatively impact productivity.
Limiting fume exposure
There is no one-size-fits-all solution to minimize fume exposure in manufacturing welding applications. To determine the best option, evaluate various products, get feedback during and encourage operator involvement to enhance buy-in.
Remember, proper training is also key for successful implementation of fume management controls. And depending on the environmental factors and operation goals, it may be necessary to implement multiple solutions from OSHA’s Hierarchy of Controls.