Capture Velocity For Welding Fumes. N Phase 3 was to measure capture efficiencies for a range of different LEV hoods positioned at various distances and orientations to the welding arc whilst monitoring weld metal integrity. At a capture velocity of faster than 03 ms the fume concentration at welders breathing zone was reduced to a level below the limit values.
LEV is the most effective means of removing contaminants from the welders breathing zone. One or more of the following capture devices are recommended. The air velocity induced in the welding zone was.
One or more of the following capture devices are recommended.
Therefore no repositioning is required since the suction automatically follows the arc. At this distance the capture velocity is 100 feet per minute which is what Air Quality Engineering seeks as the maximum because per the American Welding Society air velocities above 100 feet per minute at the arc may draw too much of the shielding gas from the weld. Weld metal porosity during gas shielded arc welding using parameters defined in Phase 1. They can keep contaminants below allowable limits.