"Types of Welding Fume Extraction"

Source capture means extracting welding fume at the point of generation — at or very close to the arc — rather than letting it disperse and then trying to clear the air. It is the foundation of effective fume control because welding fume rises and spreads quickly: once it has entered the welder’s breathing zone, it is too late to protect them efficiently.

The alternative, general or dilution ventilation, simply moves large volumes of air through the workshop to reduce average fume concentrations. It does not protect the individual welder at the arc and is generally inadequate as a primary control for welding fume. In the UK, the HSE treats all welding fume — including mild steel fume — as a substance that can cause cancer, and expects effective engineering controls such as LEV with source capture wherever welding is carried out indoors. Dilution ventilation may have a supporting role, but source capture should always come first.

Because source capture works close to the arc, it captures more fume with less airflow, which usually means lower running costs and better protection than trying to ventilate a whole building.

For any source-capture system, capture velocity — the speed of air drawn into the hood that pulls fume into the extraction system — is what actually removes the contaminant. The required capture velocity depends on the welding process, how much fume is generated and the working environment, but it falls away rapidly with distance: even moving the hood a short distance from the arc can sharply reduce how much fume is captured.

That makes hood positioning as important as the equipment itself. The hood should sit as close to the arc as practical without interfering with the work, and be placed so the rising fume plume travels naturally into the airflow before it reaches the welder’s breathing zone. Position it too close, or run excessive airflow, and you risk disturbing the shielding gas and affecting weld quality. The practical rule is simple: keep the hood close, intercept the plume, and reposition it as the weld progresses.

On-torch extraction builds a small extraction nozzle into the MIG torch itself, drawing fume away through a hose just millimetres from where it is created.

• How it works: an integrated shroud or nozzle around the torch neck captures fume at the arc and pulls it through a flexible hose to a filter unit.
• Pros: the most effective form of source capture because it follows the arc everywhere; no arm to reposition; excellent for high-fume, high-deposition MIG/MAG work.
• Cons: adds weight and bulk to the torch, which can affect comfort and access in tight joints; needs careful nozzle design to avoid disturbing the shielding gas.
• When to use it: high-output MIG/MAG production welding, robotic or repetitive welding, and any situation where consistent, hands-free capture at the arc is the priority.

Weldability SIF supplies Fumex on-torch (on-gun) extraction under the Extractability brand, alongside the units it connects to, so capture stays at the source even as the torch moves.

Mobile (portable) extraction units are self-contained, wheeled filtered units fitted with a flexible capture arm. The welder positions the arm hood near the work to draw fume away.

• How it works: an on-board fan pulls fume through the capture hood, then through a mechanical or self-cleaning filter, before returning clean air to the workshop or exhausting it.
• Pros: moves with the work; no fixed ductwork or installation; ideal where welding locations change.
• Cons: relies on the operator repositioning the arm correctly for each weld; covers one workstation at a time; capture range is limited.
• When to use it: smaller workshops, jobbing shops, maintenance and repair work, and sites where welding happens in varying positions.

A mobile unit combines an extraction arm, fan and multi-stage filtration in a single wheeled package, so you can introduce effective source capture without permanent ducting — useful for smaller shops, training environments and businesses planning future expansion. For more detail, see our guide to mobile fume extraction units.

Fixed local exhaust ventilation (LEV) with extraction arms mounts one or more articulated arms to a wall, post or bench above a dedicated welding bay, feeding into a fixed extraction unit or ducted system.

• How it works: the welder pulls the articulated arm and hood into position over each weld; the arm stays where it is set, capturing fume close to the source.
• Pros: robust, reliable source capture for a defined workstation; arms hold position; can serve a permanent welding layout efficiently.
• Cons: fixed location means the work must come to the bay; the arm must still be repositioned for each weld to stay effective.
• When to use it: established welding bays, training bays and production cells where work is carried out in a consistent location.

Extraction arms can be wall-mounted to save floor space or ceiling-mounted where wall space is limited or large fabrications need unrestricted access, and most existing workshops can be retrofitted without major structural alterations. Choosing an arm with enough reach and the right diameter for the airflow encourages welders to position the hood correctly. See our dedicated guide to welding fume extraction arms for sizing, mounting and positioning advice.

Downdraught benches draw fume downwards and away from the welder through a slotted or perforated worktop, instead of capturing it from above.

• How it works: extraction is built into the bench so fume, dust and grinding particles are pulled down and across the work, away from the breathing zone.
• Pros: keeps the work area clear and unobstructed; excellent for grinding, finishing and repetitive bench work; nothing for the operator to reposition.
• Cons: best for smaller components that sit on the bench; larger or awkward workpieces can reduce capture efficiency; not suited to in-situ or large-structure welding.
• When to use it: bench-based fabrication, grinding and finishing, and repetitive work on small to medium components.

Extraction booths and extraction walls partly or fully enclose the welding operation so that fume is contained and drawn away within the enclosure.

• How it works: an extraction wall provides a “back-draught” capture surface behind the work, while a booth surrounds the operation on several sides and extracts the contained air.
• Pros: captures fume across a larger working area without needing an arm repositioned for every weld; good for larger or variable workpieces; can also shield others from arc glare.
• Cons: requires more space and higher airflow than close capture; effectiveness depends on the welder working within the enclosure.
• When to use it: larger fabrications, variable work that won’t sit neatly under an arm, and areas where you also want to contain arc flash and spatter.

Centralised (ducted) systems connect multiple welding stations to a single high-capacity extraction fan and filtration plant via fixed ductwork.

• How it works: each bay feeds into a shared duct network; one or more large fans and a central filter unit serve the whole facility, often with self-cleaning filtration.
• Pros: efficient for many bays; consolidated maintenance and filtration; consistent extraction across a large site.
• Cons: significant installation cost and design effort; ductwork must be correctly balanced; less flexible if your layout changes.
• When to use it: large fabrication facilities and multi-bay production lines where many welders work simultaneously.

Every extraction type needs filtration, and how the cleaned air is handled matters for both compliance and running cost.

• Mechanical (disposable) filters trap fume particles and are replaced when full. They are simple and effective but carry an ongoing consumable cost.
• Self-cleaning filters use reverse pulses of compressed air to clear collected dust into a bin, extending filter life and reducing downtime — useful in higher-throughput or centralised systems.

You also choose between recirculation and exhaust to atmosphere:

• Recirculation returns filtered air to the workshop, saving the energy used to reheat replacement air, but it demands high-quality, well-maintained filtration to ensure the returned air is safe.
• Exhaust to atmosphere discharges the extracted air outside, which removes recirculation risk but loses heated air and may require external discharge consent.

As a quick pointer: choose on-torch or mobile units for changing locations and smaller shops; fixed LEV arms, downdraught benches or booths for established bays and bench work; and centralised ducted systems for large multi-bay facilities. The best choice also depends on your fume volume, process and floor plan.

For a structured decision process, see our guide to choosing a fume extraction system. For heavier-duty applications and large fabrication environments, see our industrial fume extraction guide. And remember that whichever system you install, UK law requires it to be inspected and tested — see LEV testing and compliance.

Weldability SIF supplies the Fumex range under the Extractability brand, covering on-torch (on-gun) extraction, extraction arms, mobile units, downdraught benches and centralised LEV — so a single source can match the system to your welding process, workshop layout and the number of bays you need to cover. Our team can advise on HSE guidance, COSHH compliance and equipment selection, and can help retrofit extraction to an existing workshop rather than offering a one-size-fits-all solution.