What kind of weld fume extraction is used for a welding booth?

There are several types of manual welding fume extraction methods that can be used with a welding booth. 

• Backdraft plenum: A backdraft plenum provides effective continuous fume extraction for tabletop weldments. The plenum may be integrated into the welding booth or ducted to a centralized dust collection system. Backdraft plenums pull fumes up and away from the welder’s face to keep the breathing zone clear. Since they do not require manual repositioning, they are simple for welders to use. 
• Fume arm: Fume arms are flexible, articulating arms with close-capture extraction hoods that can be positioned near the welding source to capture fumes. Fume arms may provide an advantage when working with highly toxic materials, since the capture hood can be positioned right over the weld seam for more efficient fume capture. They also require less airflow (CFM) than a backdraft plenum, providing energy savings. However, the welder must reposition the arm during welding of larger pieces to ensure that the capture hood is directly over the weld seam. Fume arms may be ducted to a centralized dust collection system, integrated into a welding booth or connected to a small portable fume extractor. 
• Fume guns: For welding booths without integrated fume extraction, fume guns provide an effective fume collection option for manual MIG welding. Fume guns use a tip extraction system for on-torch weld fume control. When used correctly, they can collect up to 90-95% of weld fume right at the source. Since fume extraction is built into the torch, welders don’t need to worry about repositioning. 
• Overhead hood systems: Sometimes, an overhead hood system is used to collect weld fume as it rises. The receiving hood is usually ducted to a centralized dust collection system. Like a backdraft plenum, this provides the advantage of not requiring the welder to reposition anything during welding. These systems are sometimes used for larger welding booths or areas where multiple welders work on large assemblies. However, depending on the type of welding and position of the welders, an overhead receiving hood may not do a good job of keeping weld fumes out of the breathing zone. For heavy weld fumes or highly toxic materials, a close capture system (e.g., fume arm) or a backdraft plenum, which pulls fumes away from the welder, is usually a better choice.
• Downdraft tables: Downdraft tables or benches are sometimes used as welding booths. Downdraft filtration systems are usually integrated with the workstation for a stand-alone solution. They work similarly to a backdraft plenum but use downward airflow instead of pulling fumes up and away horizontally. For this reason, they are not always an effective method for submicron fumes created by welding and other thermal processes, which naturally rise as they are created. A backdraft plenum is usually preferred over downdraft for a welding booth. Downdraft tables may also present a fire risk when used for welding.