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A fume extractor captures welding fume at or near the source, draws it through a multistage filtration system, and returns clean air to your workspace. That is the core function, and it matters more than most workshops currently act on. Welding fume was reclassified by the International Agency for Research on Cancer in 2017 as a Group 1 carcinogen, with sufficient evidence that it causes cancer in humans. All welding fume carries this classification, including mild steel.
Whether you run a fabrication shop in Auckland, a panel beating operation in Christchurch, or weld occasionally on a farm in the Waikato, this guide explains how fume extraction works, why an open door and a fan are not sufficient, and which system suits your setup.
What Is Welding Fume and Why Is It Dangerous?
Welding fume is not simply smoke. It is a complex mixture of metallic particles, metal oxides, and gases released when base metal, filler wire, flux, or coatings are heated to high temperatures, creating harmful welding fumes. Particles sit in the ultrafine range of 10 to 400 nanometres, meaning they travel deep into the lungs and cannot be expelled naturally by the body. Fume extractors are also used in the soldering and chemical processing industries.
Common question: "We weld stainless steel a lot. Is that more of a problem than mild steel?"
Yes. Significantly more so. The table below shows what each common base material produces and why it matters.
| Welding Material | Primary Fume Hazard | Health Risk |
| Mild steel | Iron oxide, manganese compounds | Respiratory damage; manganism (Parkinson like neurological syndrome) with long-term exposure |
| Stainless steel | Hexavalent chromium, nickel compounds | Group 1 carcinogen; hexavalent chromium is a confirmed lung carcinogen and among the most hazardous occupational fume exposures |
| Galvanised steel | Zinc oxide | Metal fume fever: a flu-like illness with onset typically 3 to 12 hours after exposure |
| Painted or coated steel | Volatile organic compounds, lead (older coatings) | Neurological and respiratory harm depending on coating composition |
| Aluminium | Aluminium oxide | Respiratory irritant; chronic exposure associated with aluminosis (pneumoconiosis) and pulmonary fibrosis |
For NZ fabricators, welding stainless steel and galvanised steel is everyday, and both sit at the more hazardous end of this table. WorkSafe NZ places a clear duty on employers to control fume exposure at source under the Health and Safety at Work Act 2015. The welding industry has also faced tighter exposure standards, including SafeWork Australia reducing acceptable welding fume limits by 80%. PCBUs must identify hazards, assess risk, and implement controls so far as is reasonably practicable, with engineering controls such as fume extraction expected before relying on RPE (respiratory protective equipment) alone.
How a Fume Extraction Process Works: Step by Step
A fume extractor can operate through four connected stages. Understanding each one helps you assess whether a given system is actually doing its job.
Stage 1: Capture
The capture point draws fumes away from the breathing zone before they reach the welder. This can be a flexible extraction arm positioned close to the weld pool, a hood attached to a hose, or a downdraft welding table that pulls fume downwards through a perforated work surface. The closer the capture point is to the source, the more effective the extraction. Efficiency drops sharply once the opening is more than a few hundred millimetres from the weld pool.
Stage 2: Suction (Motor and Fan)
A motorised fan creates the negative pressure that draws fume through the capture point and into the extraction system. The airflow volume (measured in cubic metres per hour) and the static pressure the fan can generate against ducting and filter resistance together determine real-world performance. Heavy-duty units, such as the Strata Airforce FE320 HD Heavy Duty Welding Fume Extractor, require considerably more motor capacity than units designed for occasional light welding.
Stage 3: Filtration
This is where effective fume removal actually happens within the airstream. A well-designed fume extractor uses a sequence of filter stages, each targeting a different particle size or contaminant type, covered in the section below.
Stage 4: Clean Air Return
After passing through all filtration stages, the cleaned air returns to the workspace. Most workshop installations recirculate this air rather than exhausting it outside. If the filter does not capture fine particles effectively, the air returning to the room is still contaminated.
The most effective fume extractor depends on work volume and contaminant toxicity.
Types of Filtration Used in Fume Extractors
Common question: "What exactly does a fume extractor filter out, and what does it miss?"
A quality welding fume extractor uses at least three filter stages in sequence, each targeting a different category of airborne hazard.
| Filter Stage | What It Capture | Why It Matters for Welding |
| Pre filter | Larger particles and spatter debris | Protects downstream filters from overloading quickly; the lowest cost stage to replace |
| HEPA filter | Fine and ultrafine particles; 99.97% minimum efficiency at 0.3 microns (the most penetrating particle size) | Captures the particles that penetrate deepest into lung tissue; equally or more efficient at ultrafine sizes below 0.3 microns due to diffusion |
| Activated carbon filter | Gases, ozone, nitrogen oxides, volatile organic compounds, odours | Neutralises toxic gases and strong odours that particle filters cannot address |
A system with only a pre-filter and a HEPA stage does not provide complete protection for stainless steel or coated material welding, where gas-phase hazards in welding fumes are significant. Be cautious of extractors described as "HEPA type" or "HEPA style" without a stated filtration efficiency; these are frequently well below the performance of a certified HEPA unit.
Solution: Look for a unit that specifies all three filter stages. The incoming Strata Airforce FE series units are designed with this full filtration stack as standard across the range for handling the full mix more completely.
Fume Extractor vs General Ventilation: What Is the Difference?
This is the distinction most often misunderstood in NZ workshops and the one most likely to leave people exposed.
Common question: "We just leave the roller door open. Is that not enough?"
No. Not for regular welding, stainless, or galvanised work.
An open roller door, a wall-mounted fan, or a pedestal fan blowing across the workshop dilutes and disperses airborne contaminants throughout the space. It moves contaminated air around but does not capture fumes before they reach the welder's breathing zone. General ventilation can reduce background concentrations in a large space over time, but the welder at the source is already breathing the fume cloud before it disperses.
A fume extractor captures fume at or very close to the source, before it enters the air the welder inhales. This is what WorkSafe NZ means by controlling exposure at source. It removes the hazard rather than diluting it.
The portable air-extraction ventilation fan from Proline has a legitimate role in improving overall workshop airflow. It is not a substitute for source capture extraction during welding. Both have a place, but they are not interchangeable for this purpose.
Portable vs Fixed Fume Extraction System Comparison
Common question: "We weld in different spots around the workshop. Can one unit cover the whole space?"
Yes, provided you select the right fume extraction system for different welding environments. There are two principal configurations, with a third option for specific applications.
Portable Fume Extractors
Portable units are self-contained, mounted on castors, and move wherever the welding is taking place for flexible use. They are ideal for on-site work where the extractor needs to move from site to site. This suits fabrication bays where large assemblies are worked on from multiple angles, maintenance workshops where the work arrives on vehicles or plant, or any setup where a fixed installation would leave coverage gaps.
The Strata Airforce FE110 Portable Fume Extractor is an entry-level unit suited to lighter welding applications. The FE210 range steps up with greater airflow capacity, available in three configurations: a flexible 4.3m hose with magnetic hood, a professional 3m swivelling stainless extraction arm for a dedicated welding position, and a 1200 x 800 downdraft welding table for bench work.
Fixed Extraction Arms
Fixed extraction arms are wall or column-mounted and serve a specific welding bay. FILTAIR® SWX is one example of a wall-mounted fume extraction system. They deliver consistent positioning and free up floor space, making them suitable for production environments where welding takes place at the same location every day. The trade-off is reduced flexibility if the workflow changes.
Downdraft Welding Tables
For smaller workpieces, a downdraft table draws fume downwards through the work surface and into the extraction unit below, providing excellent capture performance for bench welding tasks where a capture arm is difficult to position.
The Strata Airforce M20 Twin Motor Fume Extractor is available now and offers a capable dual-motor option for workshops that need reliable extraction immediately. The incoming FE series, from the FE110 through to the FE320 HD Heavy Duty Welding Fume Extractor, extends the range across the full spectrum of workshop demands from June 2026. W3-certified systems are intended to ensure effective welding fume extraction performance.
Example Portable Fume Extractors Available from Proline
The Strata Airforce range from Proline Industrial covers requirements from portable units for occasional welding through to heavy-duty dedicated systems for demanding production environments.
Common question: "We only weld occasionally. Do we really need a proper extractor?"
Solution: Yes. The frequency of welding does not change the nature of the hazard; it affects only the cumulative exposure over time. A portable unit like the FE110 incurs no more cost or complexity than the situation warrants, and the cost of a suitable extractor is considerably lower than the cost of a WorkSafe NZ enforcement action or a personal injury claim.
If your current setup relies on a roller door and a general fan, the question is not whether you need a fume extractor. The question is which system suits your workshop. That is covered in our companion guide: How to Choose the Right Fume Extractor for Welding.
