Proper Weld Fume Extractor and Welder Positioning

June 29, 2016

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Proper Weld Fume Extractor and Welder Positioning for Source Capture

Maximizing Indoor Air Quality for Your Welders

To get the best results from a source capture system, proper positioning of both the weld fume extractor and the welder are an important, but often overlooked, consideration. To maximize effectiveness and get the most from your investment, take the following positioning guidelines into account.

Proper Welder Positioning

When possible, the welder should position him or herself in a way that minimizes cross ventilation. Cross ventilation is air flow interference which directs the weld fume and smoke away from its intended capture point. For instance, if source capture equipment is north of the weld point and a breeze is blowing from southeast to northwest, the welder should position him or herself at the southeast corner of the welding area to minimize that cross ventilation.

It’s important to note that a cross draft may sometimes be beneficial in weld fume capture. For instance, if source capture equipment is again north of the weld point, a southern to northern draft will help guide fumes away from the welder and towards the capture equipment.

Using a welding enclosure can virtually eliminate any detrimental (or positive, for that matter) cross ventilation. If manual welding is taking place in an enclosure, it’s important to use source capture equipment strong enough to recycle fume and smoke before it builds up in the respiratory zone.

Proper Source Capture Weld Fume Extractor Placement

The most important aspect of weld fume extractor placement is to ensure that it is not pulling fume and smoke through the welder’s respiratory zone. If moveable fume arms or hoods are utilized, the capture point should be above the arc and positioned at approximately 45 degrees.

The most beneficial distance from arc to capture point will vary depending on a variety of factors, like air volume and velocity. A general rule of thumb for source capture placement is 1.5 duct diameters away. Professionals can help determine the best placement of your equipment during the assessment process.

Additional Resources

This information was first shared in the RoboVent webinar How to Capture Weld Fume at the Source. The complete version is available here.

To learn more about weld fumes, how they affect your IAQ and what you can do about them, make sure to watch RoboVent’s 5-part webinar series on the subject, available at