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Welding Booths

Process Description

Welding is a fabrication process that joins common materials such as steel, stainless steel, aluminum and others by melting the base material and adding a filler material to form a pool of molten material (the weld pool) that cools to become a strong joint. There are numerous welding processes including Gas Metal Arc (GMAW or MIG), Flux Core Arc Welding (FCAW), Shielded Metal Arc (SMAW or stick), Tungsten Inert Gas (GTAW or TIG), resistance (spot) welding and others to cover the broad range of material and process applications.

Contaminant Characteristics

The fume and by-products generated during welding processes are small in size, with over 90% being less than 1.0 µm, making the fume challenging to capture and more hazardous to exposed workers. The fume consists of a complex mixture of metals and metallic oxides originating primarily from the filler metal but can also include the base metal and surface contaminants such as dirt, scale or lubricants. The fume can include materials such as aluminum, antimony, arsenic, beryllium, cadmium, copper, chromium, cobalt, copper, iron, lead, manganese, molybdenum, nickel, silver, tin, titanium, vanadium, zinc and others. The fume also consists of shielding and process-generated gases.

Fume generation rates vary with the composition of the materials involved and welding process parameters. When welding on materials where residual oil or solvents are present, the particulate generated may be oily or greasy. Material Safety Data Sheets (MSDS) of materials being consumed in your welding process should be reviewed to understand the hazards of the materials you are working with.

Weld Fume Hazards

Exposure to fumes over time and in sufficient concentrations has been linked to respiratory, neurological and fertility problems including Metal Fume Fever and Parkinsonian Syndrome (manganism). Welding processes that contain chromium such as stainless steel or chromate coating are particularly hazardous and have been linked to various forms of cancer. In addition to health risks, uncontrolled weld fumes result in reduced worker productivity, product quality problems, factory maintenance issues and environmental concerns.

Recommended Approaches for Weld Fume Control

  • Source Capture. Whenever possible, capturing and controlling weld fume at the source is the recommended approach. Source capture involves utilizing various types of hoods to extract the fume at or near the generation source to protect the worker and prevent the fume from migrating elsewhere in the facility. Source capture is the most effective means of capture and requires the least amount of energy and initial investment to accomplish. Source capture can be accomplished utilizing fume extraction arms or local fixed hoods.
  • Containment. Different than source capture in that it does not capture directly at the source, containment isolates the welding process from the rest of facility and protects the contained area. Containment can be used where hoods proximate to the welding are not practical but the process can be isolated from other parts of the factory. An example would be a partitioned area (weld curtain) or booth with ventilation.
  • Ambient Air Collection. When source capture or containment is not possible, filtering ambient air can be utilized to control the fume concentrations to an acceptable level. Ambient systems are common in welding processes with large components or when there are overhead obstructions such as overhead cranes that make use of extraction arms or local hoods impractical. Ambient systems can be configured in a “push-pull” arrangement to push the fume away from the worker’s breathing zone and toward the collection points where the fume is then pulled into the collection system. This arrangement can improve fume control and reduce operational costs.

UAS Product Solutions for Collecting Weld Fumes

UAS offers a full line of fume extraction and collection equipment that can be utilized to safely control welding and thermally generated fumes. The list below indicates our products that are most commonly applied into welding applications. Our application engineers can help you select the right product with the appropriate options and accessories such as explosion vents (swing door or rupture panels), sprinklers, safety after filters, rotary air locks and more to meet your specific application and facility needs.

Our products that are most suitable for welding applications include:

Benefits of Weld Fume Filtration

Some of the key benefits from weld fume filtration include: 
  • Worker health protection and minimized potential long term liability
  • Energy savings and conservation through recirculated conditioned air
  • Extended machine life
  • Improved part / product quality
  • Reduced housekeeping
  • OSHA & EPA regulation compliance

Regulatory & Safety Considerations in Welding Applications

Various federal government agencies have regulations and standards in place to protect both workers and the environment from the hazards of weld fumes. Several national organizations also provide safety considerations and guidelines.

Occupational Safety and Health Administration (OSHA) Environmental Protection Agency Metal Fabrication Hazardous Air Pollutants (EPA MFHAP) 
National Institute for Occupational Safety and Health (NIOSH) American Welding Society (AWS) 
American Conference of Governmental Industrial Hygienists (ACGIH) 
  • Weld Fume Threshold Limit Value (TLV) of 5 mg/m³ 
    • Time Weighted Average (TWA) for a normal 8-hour workday and a 40-hour work week (Reference: ACGIH 1994, p. 36)
  • April 2013 manganese exposure limit guideline reduces the respirable TVL-TWA limit of 0.2 mg/m³ to 0.02 mg/m³