How to Choose the Right Fume Extraction System for Your Facility: A Practical Decision Framework

Choosing the wrong fume extraction system does not just underperform, it leaves workers exposed to airborne contaminants at concentrations that may now breach tightened Australian workplace exposure limits, and it creates a documented compliance failure at the next audit.

This article is a practical decision framework for facility managers, procurement teams, and WHS personnel who need to match the right extraction approach to their specific processes, layout, and compliance obligations. With more than 40 years of Australian-made ventilation expertise, Fanquip supplies the full range of fume extraction systems covered in this guide.

Quick Decision Overview

Three outcomes define this framework. First, identify whether at-source extraction is feasible for your process, as this is always the preferred control approach where the fume source is fixed or semi-fixed. Second, determine whether dilution ventilation is required to manage residual ambient contamination after source extraction. Third, assess whether ambient filtration using filter fans or negative air units is needed for large-volume or multi-process environments where point-source extraction alone cannot maintain acceptable air quality.

Before working through the steps, gather your process data, facility layout drawings, and workload schedules. A selection based on incomplete site data produces a system that may perform correctly under ideal conditions and fail under actual production load.

Step 1: Map Contaminants, Processes, and Compliance Obligations

Log every contaminant-generating process in the facility, noting contaminant type, source location, duty cycle, and whether the process is fixed or mobile. This mapping exercise is the foundation of every subsequent decision. Common contaminant categories include:

Welding fumes: The most compliance-critical category for most industrial facilities. The 8-hour TWA for welding fumes is 1 mg/m³, a limit that cannot be met by dilution ventilation alone in most enclosed workshop configurations. See who is responsible for ensuring compliance with the welding fumes exposure standard for compliance obligations and what control measures can be used to reduce welding fumes exposure for control hierarchy guidance.

Paint fumes and solvent vapours: Spray painting, coating, and finishing processes generate VOC-laden fumes that require specific filtration media matched to the solvent profile. See impact of paint fume exposure for health and regulatory context.

Silica and respirable dust: Cutting, grinding, drilling, and surface preparation on concrete, stone, and ceramic materials generates respirable crystalline silica. See new silica dust regulations for current and incoming limits.

Confined space gases and vapours: For processes involving gas accumulation in tanks, vessels, or enclosed plant areas, see what is a purging fan and when do you need one. Confined space gas clearance is a distinct problem requiring a different product category from fume extraction.

Three Approaches: At-Source Extraction, Dilution Ventilation, and Ambient Filtration

For a detailed explanation of how these three approaches differ in design and application, see what are the different types of fume extraction systems.

At-source extraction captures contaminants at or as close as possible to the point of generation, before they enter the breathing zone. This is the highest-order engineering control and the only approach that reliably meets the welding fume TWA limit. At-source extraction maps to mobile fume extractors, extraction arms, downdraft tables, and on-torch extraction for welding applications.

Dilution ventilation reduces ambient contaminant concentration by introducing large volumes of fresh air to dilute fumes that have already entered the workspace air. It is appropriate as a supplementary control alongside at-source extraction, or as a primary control for low-toxicity, low-concentration contaminants in well-ventilated spaces. Dilution maps to roof fans, wall fans, and axial flow fans used for whole-facility air exchange.

Ambient filtration recirculates facility air through filter media, removing particulates and some chemical contaminants without exhausting conditioned air. It suits large production environments, food processing facilities, and operations where exhausting air to atmosphere is impractical. Ambient filtration maps to filter fans and negative air units.

Facility Assessment: Layout, Airflow Path, and Winter Effects

Map the airflow path from each identified fume source to the intended exhaust or filtration point. Assess ceiling height, overhead crane travel paths, and the extent to which workflows are fixed versus mobile. Fixed extraction arms and hoods are impractical in bays where overhead cranes or mobile equipment regularly pass through. High ceilings allow fume to rise and accumulate above the occupied zone, reducing extraction effectiveness at worker height if extraction points are positioned incorrectly.

Mark fixed extraction point locations on the facility drawing, then overlay mobile workflow paths to identify zones where portable or flexible extraction is required. Avoid placing extraction points in locations where crane or forklift movement will interfere with duct runs or hose routing.

Winter conditions significantly change fume accumulation behaviour in facilities with natural ventilation. Sealed winter buildings lose passive air dilution entirely, causing fume concentrations to build faster and linger longer than summer monitoring data would suggest. See winter fume and dust hazards in industrial facilities for the full mechanism, and use the pre-winter ventilation checklist to confirm extraction adequacy before the cold season.

Map Product Categories to Situations

At-Source: Mobile Fume Extractors and Extraction Arms

Use a mobile fume extractor where fixed extraction hoods are impractical or where welding and grinding tasks move between locations within the facility. Mobile units with extraction arms position the capture point within 200 to 250mm of the fume source, which is the distance at which capture velocity is sufficient to pull fumes into the hood before they disperse into the breathing zone. Extraction efficiency drops significantly beyond that distance.

Fanquip’s mobile fume extractor is suited to manufacturing, building and construction, and wholesale and hire operations where welders and fabricators move between workstations or work on large structures that cannot be brought to a fixed extraction point. In a mobile extraction installation at Stern’s Pools, repositionable extraction arms addressed the challenge of fume control across an irregularly shaped production floor where fixed ductwork was impractical.

Downdraft Tables and Fixed Workbench Extraction

For repetitive bench-scale welding, grinding, and finishing where the work is brought to the workstation rather than the other way around, a downdraft table provides integrated source capture below the work surface, improving ergonomics while maintaining consistent extraction performance. Downdraft tables are appropriate in education, light manufacturing, and wholesale depot environments where the contaminant volume per session is moderate and the work is predictable in location.

Portable Blower Extractors and Confined Space Ventilation

For remote or site fabrication where access to fixed electrical infrastructure is limited, the portable blower extractor provides flexible supply or extraction ventilation at the work location. Portable blower extractors are appropriate where the atmosphere is confirmed non-hazardous and electrical equipment can safely operate in the space. For confined space applications where gas accumulation or flammable atmospheres are involved, see what is a purging fan and when do you need one for the correct product category.

Portable blower extractors are used in mining, oil and gas, and remote plant worksites where ventilation requirements are temporary and the work location changes between tasks.

Filter Fans, Negative Air Units, and Ambient Filtration

Where point-source extraction cannot address all contamination in a large facility, filter fans provide ambient filtration by recirculating facility air through HEPA or panel filter media. HEPA filtration captures up to 99.995% of particles at the rated particle size, making filter fans effective for fine dust and particulate control in food processing, large workshops, and smelting operations where product or process contamination is a secondary concern alongside worker exposure.

Negative air units create negative pressure containment in zones where contaminated air must not migrate to adjacent clean areas, such as asbestos remediation, lead paint removal, and pharmaceutical manufacturing. The unit draws air through the filtration media and discharges clean air outside the containment zone, maintaining a pressure differential that prevents contaminated air from escaping through gaps in the containment structure.

Design the Airflow Path and Locate Extraction Points

Size duct runs to minimise resistance. Long duct runs, sharp bends, and undersized ductwork all reduce the airflow delivered at the capture point relative to the fan’s rated output. Airflow must maintain sufficient capture velocity at the source despite duct resistance. A fan sized for the extraction volume required at the source, without accounting for duct losses, will underperform in installation.

Place extraction points as close as practical to fume sources. The 200 to 250mm guideline for extraction arm positioning applies to fixed systems as well. Every additional 100mm of distance between the capture point and the fume source reduces the proportion of generated fume captured by the system.

For mobile workflows, model the extraction point locations against the range of positions a welder or grinder will occupy during a typical shift. A single extraction arm may not cover a large weld bay if the work moves significantly. Two arms positioned at the typical extremes of the workflow path provide more consistent capture than one arm at the midpoint.

For point-of-use versus centralised ducting, point-of-use extraction (individual units at each workstation) provides better capture consistency and allows individual stations to be turned off when not in use. Centralised ducted systems suit facilities with consistent, simultaneous multi-station operation where the duct infrastructure is permanent and the extraction volume is predictable.

Dilution Ventilation and Whole-Facility Extraction

Dilution ventilation supplements at-source extraction by reducing the ambient concentration of residual contaminants that escape source capture. For the distinction between fume extractors and exhaust fans used for dilution, see difference between a fume extractor and an exhaust fan.

Axial flow fans provide high-volume air exchange for general dilution in manufacturing bays and workshops. Roof fans exhaust warm contaminated air from ceiling level, where fumes that escape source capture tend to accumulate. Wall fans provide targeted zone exhaust at process height for contaminants that do not rise to ceiling level.

Extraction systems must be supported by adequate make-up air to avoid negative pressure in the facility. A building operating under significant negative pressure reduces exhaust fan performance, may backdraft combustion appliances, and creates pressure differentials at entry points that affect contaminant distribution patterns across the facility.

Commissioning, Testing, Maintenance, and Validation

After installation, verify capture performance using calibrated airflow measurement at each extraction point. Record delivered airflow in L/s or m³/h and compare against design targets. Measure fume concentration at the worker breathing zone under representative production conditions and compare against the applicable workplace exposure standard.

Document baseline readings for each extraction point at commissioning. These are the reference values against which future maintenance checks and compliance audits are measured. Without a commissioning baseline, performance degradation over time is difficult to quantify and defend in an audit.

Schedule routine inspections covering:

• Filter condition and replacement intervals: dirty filters reduce airflow and increase motor load. Different applications require different filter media; confirm the installed media matches the contaminant profile.
• Fan condition: blade buildup, bearing wear, and belt tension on belt-drive units
• Duct integrity: check for leaks, blockages, and loose joints that reduce system airflow

How Fanquip Products Match Your Decision Outcomes

All Fanquip products are Australian-made and supported by local aftermarket service, replacement parts, and technical consultation from a team with more than 40 years of industrial ventilation experience.

Integration Checklist for Complex Industrial Facilities

• [ ] Combine at-source fume extractors with roof or wall exhaust fans for residual ambient control
• [ ] In smelters and continuous production plants, plan layered controls: source extraction first, then dilution, then ambient filtration as the third tier
• [ ] In manufacturing, account for winter sealing effects on ambient concentration. Extraction sized for summer conditions is undersized for winter operation
• [ ] In mining and oil and gas, confirm fan and motor ratings are appropriate for the hazardous area classification of each installation point
• [ ] Plan extraction infrastructure for future layout changes: fixed duct branches with blanked ports allow new extraction points without full system redesign
• [ ] Confirm make-up air volume matches or exceeds total extraction volume to prevent negative pressure

Compliance, Documentation, and Next Steps

Document every control selection decision and the technical basis for it. A control selection record that shows the contaminant identified, the exposure limit applied, the control hierarchy followed, and the extraction system specified is the foundation of a defensible compliance position at audit.

Review the compliance obligations for welding fumes specifically at who is responsible for ensuring compliance and the control measures that satisfy those obligations at what control measures can be used to reduce welding fumes exposure.

Frequently Asked Questions

What is the exposure limit for welding fumes?

The 8-hour TWA for welding fumes is 1 mg/m³. This limit cannot be met by dilution ventilation alone in most enclosed industrial workshops. At-source extraction using a fume extractor with an extraction arm or on-torch capture is required as the primary control for welding operations.

How do I choose between a mobile fume extractor and a fixed extraction arm?

Choose a mobile fume extractor where welding or grinding tasks move between locations, where overhead clearance or equipment paths prevent fixed duct runs, or where the facility layout changes regularly. Choose a fixed extraction arm where the work always occurs at the same station and the duct infrastructure is permanent.

How often should extraction system filters be replaced?

Replace filters based on the pressure drop across the filter media, not on a fixed calendar interval. Install a manometer or pressure gauge across the filter housing and replace when the drop reaches the manufacturer’s specified limit. In high-dust or heavy-production environments, this may occur more frequently than the nominal replacement interval. Log all filter changes for compliance records.

What is the difference between a fume extractor and an exhaust fan?

A fume extractor captures contaminants at the source through a hood, arm, or nozzle, processes them through filter media, and returns clean air to the facility or exhausts to atmosphere. An exhaust fan moves large volumes of air for dilution ventilation without filtration, reducing ambient concentration by air exchange rather than by capture. Both may be required in the same facility, with extractors at process points and exhaust fans for whole-facility dilution.

How do I get a system specified for my facility?

Contact Fanquip with your completed facility assessment: contaminant list, layout drawing, zone dimensions, process duty cycles, and compliance requirements. Our engineering team can recommend the right combination of at-source, dilution, and ambient filtration products, sized and mapped to your specific site. Browse the fume extractor range to begin shortlisting, or contact us directly for a consultation.