Welding fume and process ventilation

When metal is welded, a cloud of very fine particles and gases forms—welding fume. It's often invisible in large amounts in wire welding with low fume generation, but can contain substances that over time damage airways and the nervous system. That's why controlling welding fume is a fixed part of the work environment on any metal shop, not something you only address if the fume bothers you.

§What welding smoke consists of

The composition of welding fume depends on welding method, filler material and the material being welded. When welding ordinary steel, the fume contains, among other things, iron oxide, while alloy and stainless steel can release substances such as manganese, chromium and nickel compounds. Some of these substances are suspected of being able to cause chronic damage with prolonged exposure, and manganese is particularly known for being able to affect the nervous system with high and prolonged exposure.

§Requirements for ventilation at source

The Labour Authority's guidance on ventilation emphasizes that pollution should as a starting point be removed where it is created — at the source — rather than diluted in the room's air. In welding this means in practice point extraction where an extraction arm or extraction outlet is placed close to the weld point so the smoke is drawn away before it reaches the welder's breathing zone.

• 01Local exhaust pulls smoke away right where it forms
• 02Low-pressure process extraction can in many cases effectively remove all contamination from a welding process
• 03Fixed set up welding stations should have a fixed extraction system.
• 04When working at different locations, portable or mobile extraction solutions are used

§Local exhaust rather than general ventilation

Strainer ice

§Respiratory protection as last resort

Where process ventilation cannot remove the pollution sufficiently — for example during welding in confined spaces, outdoors, or on materials with heavy smoke development such as galvanized or stainless steel — it is supplemented with respiratory protection, typically a welding helmet with supplied air filter or a separate fresh air system. The protective equipment is intended as the last link in a protection chain where the source is first attempted to be removed or reduced.

§Responsibility and culture

The rules only work if the equipment is present, functioning and used. It is the employer's responsibility to provide the right ventilation solutions, but it is a shared culture at the workshop that determines whether the extraction arm is actually positioned correctly every time there is welding – even when the task is urgent and even when the smoke doesn't smell particularly strong that day.