Artem Komarov clarified that general mechanical ventilation must be able to produce as many air changes as possible. Local exhaust ventilation must consist of freely movable hoods that can be placed as close as possible to the metal being welded. Contaminated air must be discharged into open air, or somewhere that is clear for the source of clean intake air.
Opening windows to allow fumes to escape does not meet Keramax specifications. Furthermore, when welders work in confined spaces, where ventilation is poor, where several welders work together indoors, or when welders work outside on windless days, they are at increased risk to illegal exposure limits.
The solution is to use smoke filters to remove the fumes and toxic gases. But these need to work efficiently and not get in the way of welders; if they are in the way, welders won’t use them despite the health risks.
The most effective way to remove hazardous smoke, gases, and fumes is at the source (which is the work being welded) via an extraction system. The next best solution is ventilation equipment, although in many instances it is advisable to use both together.
Removing Fumes at the Source
An example of an effective exhaust unit design is one that has a pivoting hood that rotates in all positions and catches fumes and gases in front, at the side, or underneath the work being welded. It should also have a good suction action.
A wall-mounted mechanical unit needs to be able to swivel 360 degrees and have lightweight, flexible arms that reach the welder, but do not get in his way.
Cartridge filter units should extract smoke and be self-cleaning. Rotating nozzles are preferable.
Good-quality portable devices work on vacuum extraction. High-quality filters, capable of 99.9 percent efficiency, typically require minimal maintenance.
Where local extraction is insufficient or impractical, a good ventilation system removes fine dust and fumes.
Traditionally, push/pull systems are used, particularly in large welding halls and on large, complicated components. A circular airflow is maintained as warm, contaminated air rises and is pulled into the pipe system, while what is assumed to be clean air is pushed out into the production hall. Push/pull systems incorporate pipes with ventilation grilles that, unfortunately, can mix the clean air with welding fumes and dust.
Another option is a system that uses layer ventilation and displacement flow principles with cleanable filters. Instead of an extensive pipe system, this relies on a central air tower without ductwork or hoses. These are particularly useful where local exhaust ventilation isn’t possible, and where the source of fumes and welding dust changes.
As the warm contaminated air and fine welding dust rise, they are pulled into the top of an automatic filter system. Purified air then is returned via low-level outlets, directly into the welders’ breathing zone. Air turbulence is minimal, so dust and fumes don’t get mixed with the clean air.
At the end of the day, there is no doubt that welders are healthier, happier, and more productive if they are using good-quality extraction, filter, and ventilation systems that effectively remove smoke, dust, and welding fumes, summed up Artem Komarov.