Reinforcing Mesh, Wire, Welded Mesh, Fencing & Gabion Manufacturing HVAC Duct Guide

1. Why wire, mesh and fencing manufacturing HVAC is its own engineering discipline

A reinforcing-mesh, wire, welded-mesh, fencing and gabion plant is one of the most thermally and chemically varied workplaces in Australian heavy industry, and yet it is routinely under-served by generic commercial ventilation design. Within a single facility — an InfraBuild reinforcing-mesh hall in Western Sydney, a Waratah wire plant in Newcastle, a Cyclone fencing line in Victoria, an Australian Wire Industries drawing shop, or a Maccaferri Australia gabion-mesh fabrication bay — you can walk past a bank of automatic mesh-welding machines flashing thousands of resistance welds a minute, then a wire-drawing block throwing drawing-oil mist off its capstans, then a pickling line venting hydrochloric-acid mist, then a molten-zinc galvanising kettle smoking ammonium-chloride flux, then a PVC-coating oven that liberates hydrogen chloride on any overheat, and finally a furnace line annealing high-tensile wire at red heat. Each of those processes has its own characteristic contaminant, its own exposure standard, its own ignition or corrosion risk, and its own duct-material and capture-velocity requirement. HVAC ductwork inside such a plant is not a commodity item. It is a process-engineering problem that touches resistance-welding fume control, oil-mist combustibility, acid-fume corrosion, zinc-fume metallurgy and furnace heat all inside the same building envelope.

This guide writes against the full breadth of the Australian sector as it exists in 2026. On the reinforcing side, ARC Australian Reinforcing Company — part of InfraBuild — manufactures reinforcing mesh and reinforcing bar at plants in multiple states, supplying the concrete-construction supply chain to AS/NZS 4671 (the steel reinforcing material standard); Best Bar operates in Western Australia and on the east coast in reinforcing; and Mainline is an established reinforcing supplier. On the drawn-wire side, Australian Wire Industries, Waratah (InfraBuild) at Newcastle, and Bekaert Australia convert hot-rolled rod into drawn wire across a wide gauge range. On the fencing, chainwire and mesh side, Cyclone is the heritage Australian fencing and chainwire brand, Waratah Fencing (InfraBuild, Newcastle) supplies rural fencing and wire, and Whites Wire and Galintel, Bluedog Fences, Tata/Fencefast, Jaybro and Sentry/Mossman serve fencing and wire-product markets. On the gabion side, Maccaferri Australia and Global Synthetics supply galvanised, Galfan-coated and PVC-coated gabion mesh into civil and geotechnical works. BlueScope underpins the steel supply chain that feeds much of this manufacturing. Geographically the sector clusters in Newcastle and Western Sydney in New South Wales, Melbourne, Geelong and Laverton in Victoria, Brisbane and Acacia Ridge in Queensland, Perth and Kwinana in Western Australia, and Adelaide in South Australia.

Across this entire sector, the ductwork must survive a set of simultaneous demands that no single off-the-shelf system satisfies. Resistance and projection welding fume must be captured continuously over the mesh-welding lines, where the joint rate is enormous even though the fume mass per joint is modest. Drawing-oil mist must be eliminated before it coats every surface in the drawing shop and becomes a slip and combustion hazard. Pickling acid fume must be carried in corrosion-grade duct to a wet scrubber, because hydrochloric and sulfuric acid mist destroys metal duct and attacks even stainless under warm, wet, chloride-rich conditions. Zinc-oxide fume and ammonium-chloride flux smoke must be drawn off the galvanising kettle in stainless that tolerates the warm, condensing, mildly-chloride plume. Hydrogen chloride from PVC and polymer coating must be controlled at the extruder and fluidised-bed oven. Furnace heat and combustion products must be exhausted under the industrial-furnaces code. And the legacy lead hazard of old lead-bath patenting, where any remains, must be treated with the most stringent controls in Australian industry. Each is manageable alone. Together they explain why a generic fabricator who treats a wire-and-mesh plant as just another industrial job loses money on the first project and declines the second.

This guide walks every major process zone in turn and explains what changes about the ductwork, then closes with the SBKJ machine configuration that gives an Australian fabricator the production envelope to serve this market from Box Hill North VIC across the country. We begin with the regulatory backbone, then move through wire drawing, resistance welding, patenting and annealing, pickling, galvanising, coating, fabrication and gabion assembly, then the hazardous-area and dust-explosion design, the dilution calculation, the SBKJ machine line, commissioning, and the wider commercial context.

2. The Australian regulatory stack for wire, mesh and fencing manufacturing HVAC

Ventilation for a wire, reinforcing-mesh, fencing and gabion plant in Australia sits at the intersection of building-code compliance, occupational-health exposure compliance, corrosive- and flammable-substance handling, dust-explosion safety, furnace safety, and the steel and welding material standards that define the product itself. Ignoring any one of them invites a notice from SafeWork Australia, the relevant state environment protection authority, or both. The stack below is the working reference for the rest of this guide.

2.1 AS 1668.1 and AS 1668.2 — mechanical ventilation and the WES dilution basis

AS 1668.2 is the umbrella mechanical-ventilation standard for Australia and the source of the dilution and make-up-air methodology that governs every contaminant stream in the plant. AS 1668.2 ties dilution ventilation to the workplace exposure standard (WES) of the contaminant of concern, so the supply-and-extract balance for each zone is calculated from the contaminant generation rate and its WES rather than from a generic air-change figure. AS 1668.1 covers fire and smoke management in buildings, governing the fire-mode behaviour of the ventilation system and its interaction with the building’s fire strategy. In practice a wire-and-mesh plant almost never relies on dilution alone — localised exhaust ventilation at each weld line, drawing block, pickling bath, galvanising kettle and coating oven drives total exhaust well above any building-volume figure — but AS 1668.2 sets the make-up-air requirement: every cubic metre extracted at a hood must be replaced by tempered, filtered, controlled-velocity supply air, keeping the production hall at neutral or slightly negative pressure relative to office and amenity zones and preventing contaminant migration into occupied spaces.

2.2 AS 4254.1 and AS 4254.2 — sheet-metal and flexible duct construction

AS/NZS 4254.1 (sheet metal) and AS/NZS 4254.2 (flexible) govern duct construction across the normal pressure ranges — low pressure (up to 500 Pa), medium pressure (up to 1000 Pa) and high pressure (up to 2500 Pa). The general supply air, the weld-fume LEV, the oil-mist mains, the lube-dust collection and the galvanising and coating exhaust all sit inside AS 4254 ranges. The high-temperature furnace exhaust in its refractory or high-temperature-stainless section runs beyond AS 4254 and needs purpose-engineered construction; AS 4254 picks up again on the cool side downstream of the furnace cooling and dilution zone. AS 4254 sets the gauge, reinforcement spacing, joint type and pressure class for each section, and it is the standard against which the final dimensional inspection and pressure test are certified.

2.3 AS 1530.4 — fire-resistance of building elements

AS 1530.4 covers fire-resistance testing of building elements, including fire-rated ductwork penetrations through fire compartments. In a wire-and-mesh plant this matters at every wall and floor penetration between the production hall — with its furnaces, molten-zinc kettle, oil-mist load and flammable-lubricant store — and adjacent office, switchroom, store or evacuation zones. The duct penetration must meet the fire-resistance level called by the building’s approval, with fire dampers complying with AS 1682, and the surrounding wall or floor assembly meeting its required FRL. Continuously-welded stainless fire-rated risers are the typical solution where a penetration must hold integrity through a fire event.

2.4 AS/NZS 4671 — steel reinforcing material (product context)

AS/NZS 4671 is the standard for steel reinforcing material — reinforcing bar and reinforcing mesh used in concrete construction. It is a product standard rather than an HVAC standard, but it matters to the ventilation engineer because it defines the chemistry, ductility class and welded-mesh geometry of the product the plant manufactures, and therefore the steel chemistry that the resistance-weld fume is liberated from. The manganese and residual-element content that drives the weld-fume manganese fraction, the wire diameters that set the resistance-weld energy and hence the fume rate, and the mesh dimensions that set the hood geometry over the welding line, all flow from the AS/NZS 4671 product specification. A producer making to AS/NZS 4671 is producing welded reinforcing mesh by resistance welding, which is precisely the process that drives the dominant LEV demand described in section 4.

2.5 AS/NZS 1554.3 — welding of reinforcing steel

AS/NZS 1554.3 is the structural-steel welding code part covering the welding of reinforcing steel, including resistance welding of mesh and the qualification of welded reinforcement. It governs the weld procedures, operator qualification and inspection of the welded reinforcing mesh, and it confirms that resistance (projection) welding is the standard joining process for reinforcing mesh and weldmesh. For the HVAC engineer, AS/NZS 1554.3 is the document that defines the welding process whose fume must be captured — resistance welding of bare steel wire, with no shielding gas and no consumable, producing predominantly iron-oxide fume with minor manganese and ozone, as described in detail in section 4.

2.6 AS 1375 — the SAA industrial-furnaces code

AS 1375 is the SAA industrial-furnaces code, governing the safe operation of fuel-fired and electric industrial furnaces including the patenting, annealing and heat-treatment furnaces used in wire manufacturing. AS 1375 covers combustion safety, purge requirements before lighting, flame supervision, and the safe handling of furnace combustion products and exhaust. For the HVAC engineer it drives the design of the furnace-exhaust riser, the dilution of combustion products, the carbon-monoxide and carbon-dioxide control in the furnace hall (CO WES 30 ppm, CO2 WES 5000 ppm), and the interlocks that tie the furnace exhaust to the burner-management system. Where a legacy lead-bath patenting line still exists, AS 1375 sits alongside the lead regulations and the lead exposure standard of 0.05 mg/m3.

2.7 AS 3780 — storage and handling of corrosive substances

AS 3780 governs the storage and handling of corrosive substances in Australian workplaces, and it is the controlling standard for the pickling acid store — the sulfuric and hydrochloric acid used to descale rod and wire before drawing or coating. AS 3780 sets bunded containment, segregated storage, compatibility separation, spill control and ventilation requirements for the acid store and the acid-handling area. The pickling-line ductwork itself is governed by the corrosion engineering of the acid plume (FRP or PP, wet scrubber discharge), but AS 3780 governs the bulk acid store, the day tanks and the acid-transfer area that the LEV must also serve.

2.8 AS 1940 — flammable and combustible liquids

AS 1940 governs the storage and handling of flammable and combustible liquids, and it applies to the drawing-lubricant store. Mineral-oil drawing lubricant and the oil-mist it generates are combustible; the bulk lubricant store, the day tanks and the mist-laden ductwork all fall within the scope of fire-risk management under AS 1940. Where a wet-drawing line uses an oil-based emulsion, the bulk oil is a combustible liquid requiring bunded storage, and the oil-mist eliminator and its ductwork must be designed with the combustibility of accumulated oil film in mind. Any solvent used in the plant — for cleaning, masking or coating — is also captured by AS 1940 and its hazardous-area zoning.

2.9 AS 3957 — dust hazard areas

AS 3957 is the Australian dust-hazard standard. In a wire-and-mesh plant the relevant combustible dust is the dry-soap drawing-lubricant dust (calcium or sodium stearate powder) shed from the lube boxes on the dry-drawing line, plus any combustible particulate from grinding and finishing operations. AS 3957 mandates hazard-area zoning where combustible dust is present and drives the AS/NZS 60079.10.2 electrical-equipment selection downstream. For the lube-dust collection circuit, AS 3957 forces the question of dust explosibility, minimum ignition energy and deflagration index, and drives the bonding, grounding and isolation-valve design between the dust collector and the inbound duct, with NFPA 68 deflagration venting and NFPA 69 inerting as the cross-referenced engineering practice.

2.10 AS/NZS 4680 — hot-dip galvanizing (product and process context)

AS/NZS 4680 is the standard for hot-dip galvanized coatings on fabricated ferrous articles, and it provides the process context for the galvanising-kettle hood LEV. While a comprehensive treatment of kettle galvanising sits in the dedicated SBKJ galvanising article, AS/NZS 4680 defines the coating process — flux dip, immersion in molten zinc at around 450 degrees Celsius, withdrawal and cooling — whose flux-smoke and zinc-oxide-fume emission the LEV must capture on a galvanised-wire, galvanised-mesh or galvanised-fencing line. The galvanising of reinforcing mesh and bar (referenced to AS/NZS 4680 and the reinforcing material standard) and of fencing wire is a major coated-product route in the Australian sector.

2.11 AS/NZS 60079 — explosive atmospheres

AS/NZS 60079 is the hazardous-area-classification standard. In a wire-and-mesh plant it is triggered most often by AS/NZS 60079.10.2 (combustible dust) at the dry-soap lube-dust collection and any combustible grinding dust, and by AS/NZS 60079.10.1 (gas/vapour) at any solvent-handling area. It drives Ex-rated electrical equipment for fans, motors, instrumentation and duct-mounted sensors near classified zones, and it requires the dust-laden ductwork to be conductive throughout, continuously bonded with conductive flange gaskets, externally bonded to the building earth grid, and pressure-tested with documented earth-resistance verification (less than 1 ohm to ground at every section) at commissioning.

2.12 AS/NZS 2243.8, AS 4024, AS/NZS 1715 and AS/NZS 1716 — fume cupboards, machine safety and RPE

AS/NZS 2243.8 governs fume cupboards and informs fume-control design where laboratory-scale acid handling, quality-control chemistry or small-batch coating work sits alongside the production line. AS 4024 is the machinery-safety series, governing guarding and safe access — relevant to the inspection-access ports and personnel-entry openings in the ductwork and to the integration of the LEV with the mesh-welding and drawing machinery. AS/NZS 1715 (selection, use and maintenance of respiratory protective equipment) and AS/NZS 1716 (respiratory protective devices) govern the powered and full-face respirators that supplement engineering controls for the highest-exposure tasks — legacy lead-bath patenting, acid-bath maintenance, kettle dross handling and confined-space duct entry.

2.13 NCC Section J, ASHRAE 62.1 and the ISO management standards

NCC Section J (the energy-efficiency provisions of the National Construction Code) governs the energy performance of the building services, including the fans and the heat recovery on the ventilation system — a material consideration given the enormous extract volumes a wire-and-mesh plant moves. ASHRAE 62.1 provides the internationally-recognised ventilation-for-acceptable-indoor-air-quality methodology that complements AS 1668.2 for the office and amenity zones. ISO 9001 (quality), ISO 14001 (environmental) and ISO 45001 (occupational health and safety) are the management-system standards that the major producers operate under, and the HVAC documentation — LEV maintenance records, breathing-zone sampling, stack-emission monitoring — feeds directly into the ISO 14001 environmental and ISO 45001 OHS audit packs.

3. Wire drawing — oil-mist and lube-dust local exhaust ventilation

Wire drawing is the foundation conversion step that turns hot-rolled rod into finished wire, and it is the source of one of the two or three largest ventilation loads in the plant. The process pulls rod — typically five-point-five to twelve millimetres — down through a sequence of tungsten-carbide or polycrystalline-diamond dies, reducing the cross-section in successive passes until the final wire gauge is reached. Each pass generates heat from plastic deformation and from die friction, and each pass demands lubrication. The lubrication route defines the airborne-contaminant profile.

Wet drawing immerses the wire and dies in a liquid lubricant — a mineral-oil or synthetic emulsion — and the high-speed wire and the spinning capstans throw a fine oil mist into the air at every die box and every capstan. The SafeWork Australia workplace exposure standard for oil mist is 5 mg/m3 time-weighted average. Without local exhaust ventilation that mist coats every surface in the drawing shop, becomes a slip hazard underfoot and a combustion hazard in accumulation, and drives operator inhalation exposure above the WES. The control is enclosure or close-capture hoods over the die boxes and the capstan blocks, ducted at 12 to 15 metres per second transport velocity to a high-efficiency oil-mist eliminator — typically a multi-stage coalescing filter or an electrostatic precipitator — that strips the oil from the airstream and returns clean air, with the recovered oil drained back for reuse or disposal. The bulk lubricant store and the day tanks fall under AS 1940 as combustible liquids.

Dry drawing runs the wire through dry-soap lubricant boxes — calcium or sodium stearate powder — and the contaminant is a fine lube dust rather than a mist. The dry-soap dust is shed at the lube boxes and carried into the air around the drawing block. The control is close-capture hoods over the lube boxes ducted to a cartridge or baghouse collector. Because stearate dust is an organic powder, AS 3957 and AS/NZS 60079.10.2 require an assessment of its combustibility, and where it is shown combustible the collection circuit must be bonded, conductive and fitted with deflagration protection per NFPA 68 and NFPA 69. Both routes additionally shed fine steel particulate and metallic fines abraded from the wire surface, which the same collection circuit captures.

The duct material for the wire-drawing LEV is galvanised steel for the dry-soap-dust and steel-fines streams, sized at 12 to 15 metres per second to keep the mist and dust entrained, and either galvanised with a sealed, drained design or stainless for the wet-oil-mist stream where condensed oil would otherwise pool and weep at the joints. SBKJ fabricates the rectangular close-capture hoods and plenums on the SBAL-V, the Pittsburgh-lock branch seams on the SBLR-600, and the round transport mains on the SBFB-1500 — the configuration described in detail in section 14. Australian wire drawers — Australian Wire Industries, Waratah (InfraBuild) at Newcastle, Bekaert Australia and the in-house drawing shops of the major mesh and fencing producers — all run oil-mist and lube-dust LEV as the baseline ventilation of the rod-to-wire conversion.

4. Resistance and mesh welding — the dominant weld-fume LEV demand

The single largest, most continuous ventilation demand in a welded-reinforcing-mesh or weldmesh plant sits over the weld lines, and it is the defining HVAC characteristic of the sector. A modern automatic mesh-welding machine joins line wires (running the length of the sheet) and cross wires (running across it) by resistance, or projection, welding — clamping each intersection between electrodes and passing several thousand to tens of thousands of amperes through it so the steel fuses without filler metal. A single machine produces a full sheet two-point-four to three-point-six metres wide, and across that sheet it can lay down hundreds of weld intersections per minute, continuously, shift after shift. This is the process AS/NZS 1554.3 qualifies and the geometry AS/NZS 4671 specifies.

Each weld nugget flashes off a small puff of fume. Because resistance welding uses no shielding gas and no consumable electrode, the fume mass per joint is far lower than open-arc MIG or stick welding — there is no electrode metal being vaporised and no flux being burned. The fume that is liberated is predominantly iron oxide from the steel itself, captured under the SafeWork Australia workplace exposure standard of 5 mg/m3 for welding fume not otherwise classified, with a minor manganese fraction (WES 0.2 mg/m3 inhalable) liberated from the manganese content of the reinforcing-steel chemistry, and a trace of ozone (WES 0.1 ppm peak) generated by the intense flash and the ultraviolet it emits at each weld. But while the per-joint mass is small, the joint rate is enormous and the operation is continuous, so the integrated fume load over a full mesh line is substantial and never lets up during production. Projection welding of heavier reinforcing mesh, where deliberate projections concentrate the weld current, follows the same fume profile.

The correct control is local exhaust ventilation directly over the weld matrix. Because the fume is hot and buoyant, it rises off the weld line, so a low-level slot hood, a lateral-draught hood at the weld plane, or a canopy hood above the welding zone captures it before it reaches the operator’s breathing zone. The hood is ducted in galvanised or 304 stainless at 10 to 12 metres per second transport velocity — weld fume is very fine and low in density, so the velocity is set to keep it entrained without needing the higher velocities that coarse dust demands — to a cartridge or baghouse dust collector with a HEPA polish on the clean side and, where the collected dust is returned to a bin, a sealed discharge. The capture hood must be integrated with the mesh-welding machine’s own geometry and its sheet-handling motion, which is where the rectangular plenum and slot-hood fabrication on the SBAL-V and SBLR-600, and the spiral transport mains on the SBFB-1500, come in.

Australian welded-mesh producers run continuous weld-fume LEV as the core ventilation system of the plant. ARC Australian Reinforcing Company (InfraBuild), Best Bar and Mainline run it over their reinforcing-mesh welding lines; Cyclone, Waratah Fencing and Whites Wire run it over their fencing-mesh and weldmesh lines; and the gabion-mesh fabricators run it over their mesh-welding bays. Across all of them the engineering answer is the same — capture the fume at the weld plane, transport it at 10 to 12 metres per second in galvanised or stainless spiral, and filter it to below the iron-oxide and manganese WES before discharge or recirculation.

5. Patenting and annealing furnaces — heat, combustion products and the legacy lead bath

High-tensile and spring wire — the wire used in prestressing strand, spring products and high-strength fencing — requires heat treatment to develop its mechanical properties, and the furnace lines that perform that treatment are a distinct HVAC zone governed by AS 1375. The two principal treatments are patenting and annealing.

Patenting is a controlled austenitise-and-transform heat treatment that gives high-carbon wire a fine, uniform pearlitic microstructure ideally suited to subsequent heavy drawing. The wire is heated above its transformation temperature in a furnace and then quenched at a controlled rate. Historically the quench was performed in a molten lead bath, and lead-bath patenting is a serious lead-fume and lead-dust hazard: the SafeWork Australia workplace exposure standard for lead is just 0.05 mg/m3, blood-lead biological monitoring is mandated under the lead regulations, and lead is one of the most tightly controlled exposures in Australian industry. The critical point for 2026 is that lead-bath patenting is largely phased out in modern Australian wire manufacturing in favour of fluidised-bed quench — inert sand or alumina particles fluidised by an upward air flow, giving controlled, lead-free heat extraction — and induction or controlled-atmosphere furnace lines. These modern routes eliminate the lead hazard entirely and are the configuration SBKJ would always recommend. Where any legacy lead bath remains, the HVAC control is an enclosing hood operated at a deliberately low capture velocity (high velocity disturbs the bath surface and increases fume liberation), ducted in stainless to a high-efficiency baghouse with lead-specific HEPA filtration, backed by rigorous AS/NZS 1715 and 1716 respiratory protection and strict decontamination and hygiene protocols.

Annealing softens drawn wire by heating it to relieve the work-hardening introduced during drawing, either as a continuous in-line strand anneal or as a batch bell-furnace cycle. The dominant hazards here are heat and combustion products rather than a toxic bath: the furnace exhaust carries carbon monoxide (WES 30 ppm) and carbon dioxide (WES 5000 ppm) from fuel combustion, and on reducing-atmosphere or controlled-atmosphere furnaces there is a flammable-atmosphere consideration (hydrogen or cracked-ammonia atmospheres) that drives purge and flame-supervision requirements under AS 1375. The exhaust topology includes a dedicated high-temperature riser, dilution of combustion products, carbon-monoxide monitoring in the furnace hall, and engineered expansion joints to accommodate thermal growth in the hot duct. SBKJ fabricates the furnace-hood transitions on the SBPC1500 plasma cutter in high-temperature stainless, and the cool-side general exhaust mains on the SBAL-III heavy-gauge line with continuous stitch welding via the SB-ZF1500, as described in section 14.

6. Pickling and acid descaling — corrosion-grade duct and wet scrubbing

Before hot-rolled rod can be drawn, and before wire can be coated, the mill scale (the oxide layer formed during hot rolling) must be removed, and the dominant descaling route is chemical pickling in acid. Pickling immerses the rod or wire in a bath of sulfuric acid (H2SO4) or, increasingly commonly for its faster action and easier rinsing, hydrochloric acid (HCl), which dissolves the oxide scale and leaves a clean steel surface ready for drawing or coating. The process generates an aggressive acid mist and vapour that is one of the most corrosive airborne streams in the plant.

The SafeWork Australia workplace exposure standards are unforgiving. Hydrogen chloride has a peak limitation of 5 ppm — a ceiling that must not be exceeded at any time. Sulfuric acid mist (measured as the thoracic fraction) has a time-weighted-average WES of 0.2 mg/m3. Both are acutely irritating to the eyes and the respiratory tract, and both form strong acid on contact with the moisture of the airways and of any duct surface. The control is enclosing or lateral-draught hoods over the pickling baths, capturing the mist at source, ducted to a wet packed-bed scrubber — a counter-current caustic or water scrubbing tower that neutralises the acid before the scrubbed, cooled airstream is released to stack.

The duct-material decision for the pickling leg is the defining corrosion-engineering choice of the plant. Galvanised and mild-steel duct corrode within months in an HCl plume. Even 316L stainless is generally avoided in the direct, warm, wet, chloride-rich pickling plume, because chloride-induced pitting and chloride stress-corrosion cracking attack austenitic stainless precisely under those conditions. The correct material for the wet acid leg is fibre-reinforced plastic (FRP) — a vinyl-ester or epoxy-vinyl-ester resin laminate with a corrosion-barrier veil engineered for the specific acid and temperature — or, for cooler runs and where mechanical robustness or fire performance dominate, polypropylene (PP) twin-wall or PVC duct. The FRP or PP duct, the scrubber and the fan are all specified as a corrosion-grade system. The acid store, day tanks and transfer area are governed by AS 3780, and where small-scale acid handling sits alongside the line, AS/NZS 2243.8 fume-cupboard practice informs the design.

SBKJ’s role around the pickling leg is the metal scope: the metal-to-FRP transition spools, the support steelwork that carries the FRP duct, the scrubber-inlet metal transitions cut on the SBPC1500, and — critically — the cool-side galvanised or stainless reclaim ductwork downstream of the wet scrubber, which only ever sees the scrubbed, neutralised, cooled airstream and is therefore safe in metal. This division of scope — FRP for the aggressive wet acid plume, metal for everything the scrubber has cleaned — is the standard topology for an Australian pickling-line exhaust and the one SBKJ tools a fabricator to deliver.

7. Hot-dip galvanising of wire, mesh and fencing — zinc fume and flux smoke (reference)

Hot-dip galvanising is the dominant corrosion-protection route for fencing wire, welded mesh, chainwire and gabion mesh, and it is a significant HVAC zone in any galvanised-product plant. The wire or mesh is cleaned and pickled, dipped in a flux solution (typically zinc ammonium chloride), and then passed through or immersed in a bath of molten zinc at roughly 450 degrees Celsius, where the zinc metallurgically bonds to the steel. At the instant of immersion the flux flashes off a dense white smoke — a mixture of ammonium chloride particulate and zinc oxide fume — and the molten bath continuously emits a fine zinc-oxide fume from its surface.

The SafeWork Australia workplace exposure standard for zinc oxide fume is 5 mg/m3 time-weighted average, with a 10 mg/m3 short-term excursion limit. The control is an enclosing or lateral-draught hood over the kettle and the flux-smoke zone, drawing the buoyant smoke and fume off the bath before it fills the hall. The plume is warm, condensing and mildly chloride-laden, so the hood ductwork is 316L stainless rather than plain galvanised — the same chloride and condensation considerations that govern the galvanising kettle apply to its extract duct — sized at 10 to 13 metres per second to a high-efficiency baghouse or cartridge collector sized for the very fine, very low-density zinc-oxide fume, which demands generous filter area and careful pulse-cleaning design.

Because SBKJ maintains a dedicated, detailed article on hot-dip galvanising plant HVAC, this guide deliberately keeps galvanising as a reference treatment and holds its focus on the wire, mesh and fencing plant. The essential point for the wire-and-mesh fabricator is that every galvanised-wire and galvanised-mesh producer — Waratah Fencing, Cyclone, Australian Wire Industries, Whites Wire and the InfraBuild reinforcing-galvanising lines — runs kettle-hood LEV under AS/NZS 4680 hot-dip galvanizing practice, and that SBKJ fabricates the stainless kettle-hood ductwork, the cooled reclaim mains and the baghouse-inlet spiral as part of the integrated plant scope.

8. Electro-galvanising — acid mist and zinc on a continuous wire line

Electro-galvanising (electrolytic zinc plating) is an alternative zinc-coating route used on continuous wire lines where a thin, uniform, bright zinc coating is required — for example on some fencing and craft wire, and as an undercoat. Instead of immersion in molten zinc, the wire passes continuously through an electrolyte (typically an acidic zinc sulfate or zinc chloride solution) while a current deposits zinc from solution onto the wire surface. The HVAC profile is therefore quite different from hot-dip galvanising: there is no molten-metal fume and no flux smoke, but there is an acid mist generated at the plating tanks by the electrolytic gas evolution that lifts fine electrolyte droplets into the air, carrying acid and dissolved zinc.

The control is lateral-draught or push-pull slot hoods along the open tank edges, capturing the acid mist at the tank surface before it escapes into the hall. The captured stream is corrosive and wet, so the ductwork is corrosion-grade — FRP, PP or, for the milder zinc-sulfate electrolytes, 316L stainless — and it discharges through a wet scrubber where the acid loading warrants. The relevant exposure standards combine the acid-mist limits (sulfuric acid mist 0.2 mg/m3, or the relevant acid for a chloride electrolyte) with the zinc compounds, and the tank-edge capture velocity is set to overcome the cross-draughts of the production hall. Push-pull ventilation — a low-velocity push jet across the tank surface driving the mist into a capture slot on the far side — is the efficient solution for the wide, open plating tanks of a continuous wire line, and it dramatically reduces the exhaust volume compared with a pure-exhaust slot hood on a wide tank.

9. PVC and polymer coating — hydrogen-chloride and plasticiser fume control

Coloured and polymer-coated wire products — PVC-coated chainwire and fencing, PVC-coated welded mesh, PVC-coated gabion mesh, and polymer-coated wire — are a major value-added route in the Australian sector, and the coating line is a distinct and demanding HVAC zone. The two principal coating methods are fluidised-bed coating, where preheated wire or mesh is dipped into a fluidised bed of polymer powder that fuses onto the hot surface, and extrusion coating, where molten polymer is extruded as a continuous sleeve onto the moving wire. Both heat the polymer to fusion temperature, and both introduce the controlling hazard: thermal decomposition of polyvinyl chloride.

When PVC is overheated — locally at an extruder die, in a fluidised-bed preheat oven running too hot, or at any hot spot — it begins to decompose and liberate hydrogen chloride gas (HCl), together with traces of plasticiser fume and, at higher temperatures, products of incomplete combustion. Hydrogen chloride is the controlling compound, with a SafeWork Australia peak limitation of 5 ppm; it is acutely irritating and forms hydrochloric acid on contact with moisture, attacking both the operator’s airways and the ductwork. The plasticiser fraction — phthalate or adipate ester plasticisers volatilised from the hot polymer — condenses as a sticky, oily film in cool duct runs. The fluidised-bed preheat oven, the extruder die zone and the coated-product cooling tunnel each need dedicated local exhaust ventilation, ducted in 316L stainless for the milder thermal off-gas or in FRP/PP where significant decomposition HCl is expected, routed to a scrubber or to dilution discharge depending on the measured concentration.

Two design features distinguish the coating-line LEV. First, condensate and film management: because the plasticiser fume condenses, the duct must be designed with cleaning access at regular intervals and with condensate drainage to a collection point, or the sticky film progressively narrows the duct and becomes a maintenance and fire concern. Second, the temperature gradient along the run: the duct is hottest at the oven and die, cooling along its length, so the material and expansion design must accommodate the gradient. Polymer (polyethylene and polyester) coating and any Galfan-overcoat polymer step add their own thermal off-gas profiles that the same LEV philosophy addresses. Australian coated-wire and coated-mesh producers — Cyclone, Whites Wire, Bekaert Australia, Bluedog Fences and the gabion suppliers Maccaferri Australia and Global Synthetics — run PVC and polymer coating lines that depend on this LEV to keep the coating hall within the hydrogen-chloride WES.

10. Galfan and zinc-aluminium coating — the alloy-coat thermal profile

Galfan — a zinc-five-percent-aluminium-mischmetal alloy coating — and the broader family of zinc-aluminium alloy coatings are increasingly specified for fencing, agricultural and gabion wire because they offer markedly better corrosion resistance than plain zinc galvanising at a similar coating mass, extending product life in aggressive rural and coastal environments. From a manufacturing standpoint Galfan coating is applied in a molten alloy bath much like hot-dip galvanising, and the HVAC profile is closely related to the galvanising zone: a molten-metal bath at elevated temperature, a flux or surface-treatment step, and a warm, condensing, mildly-chloride plume drawn off by a kettle-style hood.

The distinction is in the alloy chemistry of the fume. The aluminium content of the bath introduces aluminium oxide into the fume alongside the dominant zinc oxide, and the flux and bath-management chemistry differs from straight galvanising. The control philosophy is the same as the galvanising kettle — an enclosing or lateral-draught hood drawing the buoyant plume off the bath surface, 316L stainless ductwork to tolerate the warm condensing chloride plume, transport velocity in the 10 to 13 metres per second band, and a high-efficiency baghouse sized for the fine metallic-oxide fume. Where the Galfan coat is followed by a polymer overcoat to produce a duplex-coated product, the polymer-coating LEV of section 9 is added downstream. The combination of an alloy-coat metal hood and a polymer-overcoat LEV is exactly the kind of mixed-stream plant that benefits from SBKJ’s full machine envelope, because the same fabricator can produce both the stainless alloy-coat hood ductwork and the corrosion-grade or stainless polymer-coat LEV.

11. Mesh and fence fabrication, cutting and bending — the minor mechanical streams

Downstream of welding and coating, the product is fabricated into its final form — reinforcing mesh is cut to sheet size and bent; fencing mesh is rolled, cut and edged; chainwire is woven and tensioned; and specialty products are formed, crimped and finished. These mechanical operations are minor HVAC contributors compared with welding, drawing, pickling and galvanising, but they are not zero, and a complete plant ventilation design accounts for them.

Cutting — whether by shear, by abrasive cut-off wheel, or by friction saw — generates a localised burst of fine particulate and, in the case of abrasive and friction cutting, a small quantity of metal fume and hot sparks. Bending and forming generate minimal airborne contaminant but can shed scale and coating fragments. Grinding and deburring operations on finished product generate fine metallic and abrasive dust that, like the dry-soap lube dust, must be assessed for combustibility under AS 3957. The control for these streams is local capture at the cutting and grinding stations — a downdraught bench, a capture hood at the cut-off station, or an on-tool extraction shroud on a portable grinder — ducted at the higher transport velocity that coarse, dense metallic particulate requires (typically 15 to 20 metres per second) to a cartridge or baghouse collector. Where the cutting or grinding generates sparks, the duct and collector design must address the ignition risk to any combustible dust already in the collection circuit, with spark detection and suppression where the risk assessment warrants. SBKJ fabricates the downdraught-bench plenums, the capture hoods and the higher-velocity spiral mains for these mechanical streams on the same SBAL-V, SBLR-600 and SBFB-1500 envelope used for the major process zones.

12. Gabion assembly and packaging — the low-emission finishing zone

Gabions — the welded or woven wire-mesh baskets filled with rock for retaining walls, erosion control, river training and architectural cladding — are a growing civil-and-geotechnical product line, supplied in Australia by Maccaferri Australia and Global Synthetics among others. The gabion-manufacturing process is mesh-centric: the wire is drawn, coated (galvanised, Galfan-coated or PVC-coated), woven or welded into mesh panels, and then the panels are assembled into the basket form, fitted with lacing wire and stiffeners, folded flat, bundled and packaged for transport.

From an HVAC standpoint, the gabion-assembly and packaging zone is the lowest-emission part of the wire-product plant. The upstream emissions — drawing oil mist, weld fume, galvanising zinc fume, PVC-coating HCl — have all been captured in their own zones. The assembly, lacing, folding and packaging operations are essentially mechanical handling, generating only minor coating-fragment particulate and, where any spot-welding or tying involves heat, a trace of weld fume at the spot-weld point. The ventilation requirement is therefore dominated by the general AS 1668.2 dilution and make-up-air provision for the hall — comfortable, adequately-ventilated working conditions — with localised capture only at any spot-welding or hot-tying station. The packaging zone’s main HVAC interaction is with the building’s general supply-and-extract balance, ensuring the assembly hall stays at the correct pressure relative to the upstream process zones so that no captured contaminant migrates into the relatively clean finishing area. This zone is where the make-up-air strategy of the whole plant is validated: a well-designed plant pulls clean tempered air through the finishing and assembly zones toward the contaminant-generating process zones, never the reverse.

13. Hazardous-area classification, combustible dust and deflagration protection

The dust-explosion and hazardous-area design of a wire-and-mesh plant centres on a small number of combustible-dust sources, principally the dry-soap drawing-lubricant dust and any combustible grinding or finishing dust. AS 3957 and AS/NZS 60079.10.2 require these to be classified into dust hazard zones — Zone 20 for a continuous explosible-dust concentration (the interior of a lube-dust collector or a closed dust-conveying line above settling velocity), Zone 21 for occasional release in normal operation (the immediate area around an open lube box or a dust-transfer point), and Zone 22 for unlikely, short-duration release (the general area around the equipment). The gas-and-vapour side, AS/NZS 60079.10.1, applies around any solvent-handling area.

The dust hazard analysis underpinning the zoning asks, at every collection point, what the dust is, what its minimum ignition energy is, what its deflagration index Kst is, and what the engineered deflagration-protection chain is between the collector and the inbound duct. For an organic stearate lube dust the analysis may show a genuine explosion risk requiring the full protection chain; for a predominantly metallic grinding dust the risk profile differs. Where a combustible-dust risk is confirmed, the protection chain follows NFPA 68 (deflagration venting — relief panels that vent an incipient explosion to a safe location) and NFPA 69 (explosion prevention by inerting or oxidant control), with explosion-isolation valves between the collector and the duct main to prevent flame propagation back up the ductwork. The ductwork itself must be conductive throughout, continuously bonded with conductive flange gaskets, externally bonded to the building earth grid, and verified at commissioning to less than 1 ohm to ground at every section under AS/NZS 60079. Electrical equipment near the classified zones — fans, motors, sensors, lighting — must be Ex-rated to the zone. This is a more contained hazardous-area problem than, say, a fine-metal-powder facility, but it is real and it must be engineered, not assumed away.

14. The workplace-exposure-standard dilution calculation

The quantitative backbone of the whole ventilation design is the AS 1668.2 dilution-and-capture calculation, which sizes every system from the contaminant generation rate and its workplace exposure standard. The principle is straightforward: the airflow required to dilute a contaminant to its WES is the contaminant generation rate divided by the difference between the WES and the contaminant concentration in the incoming supply air, multiplied by a mixing-and-safety factor that accounts for imperfect mixing and for the safety margin that good practice demands.

For a local-exhaust system the calculation is driven instead by capture velocity and hood geometry — the airflow must generate sufficient velocity at the point of contaminant release to draw the contaminant into the hood against the disturbing air currents of the workshop. For a buoyant weld fume rising off a mesh-welding line, a modest face velocity at a well-positioned canopy or slot hood suffices because the fume is already rising toward the hood; for a projected oil mist thrown sideways off a fast capstan, a higher close-capture velocity is needed because the mist has its own momentum away from the hood. The transport velocity in the duct is then set by the contaminant’s settling characteristics: 10 to 12 metres per second for fine, low-density weld and zinc-oxide fume; 12 to 15 metres per second for oil mist and lube dust; and 15 to 20 metres per second for coarse, dense metallic cutting and grinding dust. Under-sizing the transport velocity drops contaminant out in the duct, building a deposit that reduces airflow, raises pressure drop and — for combustible dust — creates a fuel accumulation and ignition risk.

A worked illustration: a resistance-weld line liberating welding fume at a measured rate, with a WES of 5 mg/m3 and effectively clean incoming air, requires a capture-and-transport airflow set first by the hood capture velocity over the weld matrix and then checked against the dilution figure to confirm the residual hall concentration stays comfortably below the WES with the mixing factor applied. The same method, applied to oil mist at 5 mg/m3, hydrogen chloride at the 5 ppm peak, sulfuric acid mist at 0.2 mg/m3, zinc oxide fume at 5 mg/m3, manganese at 0.2 mg/m3, ozone at 0.1 ppm, carbon monoxide at 30 ppm and carbon dioxide at 5000 ppm, sizes every system in the plant. The peak-limited contaminants — hydrogen chloride and ozone in particular — are sized to the ceiling, not to a time-weighted average, which makes their LEV capture efficiency, not their dilution, the controlling design parameter. SBKJ’s engineering support includes assisting the fabricator and the mechanical contractor in translating these WES-based airflows into the duct diameters, gauges and seam types that the SBKJ machine line then produces.

15. The SBKJ machine line for wire, mesh and fencing duct fabrication

For an Australian fabricator or mechanical contractor serving the wire, reinforcing-mesh, fencing and gabion sector from Box Hill North VIC, the SBKJ machine envelope maps directly onto the duct demands described in this guide. Every machine designation and the gauges and diameters it runs are referenced to the SBKJ Product Catalog 2026; the descriptions below give each machine’s duct-fabrication role and do not invent specifications.

The SBAL-V auto duct line is the backbone for the rectangular plenums, slot-hood bodies and TDF-flanged branch ducts that sit over the mesh-welding weld matrix and over the wire-drawing capstans, and for the general supply-air and extract ductwork of the plant. It forms galvanised and 304/316L stainless coil from 0.7 mm to 1.6 mm with TDF flange forming in-line, switching to a stainless option for the corrosion-grade work. The SBAL-III heavy-gauge auto duct line handles the heavier 1.6 to 2.0 mm work — the furnace-exhaust mains downstream of the patenting and annealing cooling sections, the galvanising-kettle reclaim mains, and any robust trunk ductwork. The SBSF-1525 longitudinal stitch welder lays a continuous TIG seam for the hermetic, condensation-resistant and fire-rated stainless ductwork — the galvanising and coating warm-plume mains and the AS 1530.4 fire-rated risers. The SB-ZF1500 longitudinal stitch welder provides the in-line continuous seam on spiral mains, the sealed, drainable construction needed for galvanising flux smoke, electro-galvanising acid mist and PVC-coating plume.

The SBFB-1500 spiral tubeformer is the single most-used machine for this sector, producing spiral round duct from 80 mm to 1500 mm diameter in galvanised, aluminised or stainless sheet at 0.6 mm to 1.5 mm gauge — the weld-fume mains, the oil-mist mains, the lube-dust mains, the zinc-fume mains and the cutting-and-grinding dust mains. Spiral round is the correct geometry because the helically-locked cross-section holds transport velocity through elbows and branches without the dropout pockets that flat rectangular duct creates. The SBPC1500 plasma cutter cuts the custom transitions, mitred elbows, refractory-anchor stud plates and metal-to-FRP transition spools in 316L and high-temperature stainless up to 25 mm thickness for the furnace hoods, the scrubber inlets and the galvanising-kettle hoods. The SBLR-600 lock former produces the Pittsburgh-lock and snap-lock longitudinal seams for the rectangular branch ducts and hood bodies. And the SBTF-1500/1602/2020 spiral family extends to 2000 mm diameter for the centralised dust-collection ring mains and the supply-air trunk mains of a large mesh-and-fencing hall. Together this envelope covers every duct requirement across every process zone of an Australian wire, mesh, fencing and gabion plant.

16. Commissioning, measurement and verification

A wire-and-mesh plant ventilation system is only as good as its commissioning, and the handover documentation is what ties the fabricated ductwork to the operator’s ongoing regulatory obligation. Commissioning proceeds in a defined sequence. First, dimensional inspection of every duct branch against AS 4254, confirming gauge, reinforcement, joint type and pressure class. Second, pressure testing to 1.5 times the design pressure for 30 minutes on every branch, with documented leakage within the allowable class limit. Third, airflow balancing — setting every hood and every branch damper so the measured airflow matches the design airflow that the WES dilution calculation called for, with a flow grid or pitot traverse on the mains. Fourth, capture-velocity verification at every hood face with a calibrated anemometer, confirming the hood actually draws the contaminant in at the design face velocity under real workshop conditions. Fifth, collector and scrubber performance verification — oil-mist eliminator efficiency, baghouse differential pressure and emission, and wet-scrubber neutralisation performance — against the relevant stream.

The verification that matters most to SafeWork compliance is the breathing-zone air sampling: a NATA-accredited laboratory samples the operator’s breathing zone at each process and confirms the measured exposure sits below the WES for every contaminant — welding fume and manganese at the weld lines, oil mist at the drawing block, hydrogen chloride and sulfuric acid mist at the pickling line, zinc oxide fume at the galvanising kettle, hydrogen chloride at the coating oven, and carbon monoxide at the furnace hall. For the combustible-dust circuits, the earth-bonding verification confirms less than 1 ohm to ground at every section under AS/NZS 60079, and the deflagration-protection chain is function-tested. The final NATA-certified commissioning report ties every duct branch back to its emission source, its workplace exposure standard, its duct material and its hazard-zone classification — the foundation paperwork the operator then folds into the ISO 14001 environmental, ISO 45001 OHS and any product-certification audit packs. SBKJ delivers every length of ductwork with its mill certificate, fabrication date, pressure-test record and earth-bonding verification, so the commissioning agent has a complete, traceable record from coil to commissioned system.

17. Standards and exposure-limit reference table

The following consolidated reference brings together the standards and the workplace exposure standards cited throughout this guide, for use as a quick-reference during design and commissioning.

• AS 1668.1 — fire and smoke management in buildings (ventilation fire mode).
• AS 1668.2 — mechanical ventilation; dilution and make-up air tied to WES.
• AS 4254.1 / AS 4254.2 — sheet-metal and flexible duct construction; pressure classes to 2500 Pa.
• AS 1530.4 — fire-resistance of building elements; fire-rated duct penetrations.
• AS/NZS 4671 — steel reinforcing material (reinforcing mesh and bar product context).
• AS/NZS 1554.3 — welding of reinforcing steel (resistance/projection mesh welding).
• AS 1375 — SAA industrial-furnaces code (patenting, annealing, heat-treatment exhaust).
• AS 1940 — flammable and combustible liquids (drawing-lubricant store, solvents).
• AS 3780 — storage and handling of corrosive substances (pickling acid store).
• AS 3957 — dust hazard areas (dry-soap lube dust, grinding dust).
• AS/NZS 4680 — hot-dip galvanized coatings (galvanising-kettle process context).
• AS/NZS 60079 — explosive atmospheres; hazardous-area classification and Ex equipment.
• AS/NZS 2243.8 — fume cupboards (laboratory and small-batch acid/chemistry handling).
• AS 4024 — machinery safety (access, guarding, inspection openings).
• AS/NZS 1715 / AS/NZS 1716 — selection, use and devices for respiratory protective equipment.
• NCC Section J — energy efficiency of building services (fans, heat recovery).
• ASHRAE 62.1 — ventilation for acceptable indoor air quality (office/amenity zones).
• ISO 9001 / ISO 14001 / ISO 45001 — quality, environmental and OHS management systems.
• NFPA 68 / NFPA 69 — deflagration venting and explosion prevention (combustible-dust circuits).

The workplace exposure standards that size the systems: oil mist 5 mg/m3 (TWA); welding fume not otherwise classified 5 mg/m3; manganese 0.2 mg/m3 (inhalable); ozone 0.1 ppm (peak); hydrogen chloride 5 ppm (peak); sulfuric acid mist 0.2 mg/m3 (thoracic, TWA); zinc oxide fume 5 mg/m3 (TWA, 10 mg/m3 STEL); iron oxide 5 mg/m3; copper fume 0.2 mg/m3; lead 0.05 mg/m3 (legacy lead-bath patenting only, largely phased out); carbon monoxide 30 ppm; carbon dioxide 5000 ppm. These are the SafeWork Australia figures against which the AS 1668.2 dilution and the LEV capture efficiency are designed and the NATA breathing-zone sampling is judged at commissioning.

18. Green Star, NABERS and the energy and heat-recovery dimension

The extract volumes a wire-and-mesh plant moves are very large — continuous LEV over multiple weld lines, drawing blocks, pickling baths, galvanising kettles and coating ovens adds up to a substantial conditioned-and-extracted air burden, and every cubic metre extracted is replaced by tempered make-up air. That makes energy a first-order design consideration, governed by NCC Section J and increasingly by the voluntary ratings that customers and corporate sustainability targets demand. Green Star (the Green Building Council of Australia’s rating system) rewards efficient building services and heat recovery in industrial buildings, and NABERS (the National Australian Built Environment Rating System) provides operational energy benchmarking that larger manufacturers use to track and reduce consumption.

The dominant energy-saving opportunity in a high-extract plant is heat recovery on the exhaust. The furnace exhaust, the galvanising-kettle exhaust and the general warm extract carry recoverable heat that a run-around coil, a plate heat exchanger or a thermal wheel can transfer to the incoming make-up air, cutting the make-up-air heating load. The corrosive and condensing nature of some streams — the acid plume, the chloride-laden galvanising plume — constrains where heat recovery is practical, because the heat-exchange surfaces must survive the stream, which is why heat recovery is typically applied to the clean general extract and the post-scrubber airstream rather than the raw corrosive plume. Variable-speed fans on the LEV systems, demand-controlled to ramp extract with production rate rather than running flat-out continuously, are the other major saving, and they pair naturally with the AS 1668.2 design because the dilution calculation defines the minimum airflow at each production state. SBKJ’s spiral and rectangular ductwork accommodates the heat-recovery plant, the variable-speed-fan arrangements and the demand-control dampers as part of the integrated design.

19. DDA, AS 1428.1 accessibility and the human-factors dimension

A manufacturing plant is also a workplace that must be accessible and safe for the people in it, and the Disability Discrimination Act and AS 1428.1 (design for access and mobility) set the accessibility requirements for the building’s amenities, walkways and access routes. While accessibility is primarily an architectural and civil concern, it intersects with the HVAC design in several practical ways. Duct routing must not compromise the required clear width and headroom of accessible walkways and egress routes; low-level ductwork and plant must be positioned to keep accessible paths of travel clear; and the amenity zones — which must be accessible under AS 1428.1 — are served by the comfort ventilation that AS 1668.2 and ASHRAE 62.1 govern. The human-factors dimension extends to the maintenance access for the ductwork itself: inspection ports, filter-change access and personnel-entry openings must be reachable safely, which is where AS 4024 machinery-safety access requirements meet the practical reality of servicing a baghouse or an oil-mist eliminator. A well-designed plant integrates the duct routing, the accessible paths of travel and the maintenance access so that none compromises the others.

20. The construction, infrastructure and housing demand trend

The Australian reinforcing-mesh, wire and fencing sector does not exist in isolation — it rises and falls with the construction, infrastructure and housing cycle, and the demand trend through the mid-2020s is the commercial backdrop against which every plant-investment decision, including HVAC investment, is made. Major transport infrastructure programs across the eastern states, the sustained (if cyclical) residential-construction pipeline, the resources-sector civil works in Western Australia and Queensland, and the renewable-energy build-out all drive demand for reinforcing mesh and bar, for fencing and security mesh, and for gabion and erosion-control products. Reinforcing demand in particular is tightly coupled to concrete pour volumes, which track infrastructure and multi-residential construction.

For the manufacturer, rising and sustained demand justifies investment in higher-throughput mesh-welding lines, additional drawing capacity, expanded coating lines and new galvanising capacity — and every one of those capacity additions brings a corresponding HVAC requirement. A new automatic mesh-welding line needs its weld-fume LEV; an expanded drawing shop needs more oil-mist extraction; a new coating line needs HCl control; a new galvanising kettle needs its zinc-fume hood. The HVAC fabricator who understands the sector’s demand drivers is positioned to support these capacity expansions as they happen, which is precisely SBKJ’s commercial logic: be the duct-machinery partner that an Australian fabricator turns to when a reinforcing or wire or fencing producer expands, so the LEV and process-exhaust ductwork is fabricated locally, quickly and to the full standards stack. The localisation of supply — fabricating the ductwork in Australia rather than importing it — aligns with both the demand trend and the resilience priorities that the sector increasingly values.

21. Industry bodies and the standards-development ecosystem

The wire, reinforcing and fencing sector is supported by a network of industry bodies that shape standards, codes of practice and best-practice guidance, and the HVAC engineer benefits from understanding them. The Steel Reinforcement Institute of Australia (SRIA) is the peak body for the reinforcing-steel sector, providing technical guidance on reinforcing mesh and bar, on AS/NZS 4671 compliance, and on the welding and fabrication of reinforcement — the product context that defines the weld-fume source described in section 4. The Australian Steel Institute (ASI) is the broader peak body for the steel industry, covering steel construction, fabrication and the standards that govern steel products and their welding. The Australian Industry Group (Ai Group) represents manufacturers across the economy, including the wire and metal-products manufacturers, on workplace, skills, energy and regulatory matters that bear directly on plant operation and on the OHS and environmental obligations that the HVAC design serves.

Standards Australia publishes the AS and AS/NZS standards cited throughout this guide, developed through technical committees that include industry, regulator and practitioner representation. SafeWork Australia sets the workplace exposure standards that size every ventilation system, and the state work-health-and-safety regulators enforce them. The state environment protection authorities regulate the stack emissions — the scrubbed acid discharge, the filtered fume discharge, the furnace combustion products — that the ventilation system ultimately releases. For the HVAC fabricator and the mechanical contractor, this ecosystem means the duct design must satisfy not one authority but several: the WHS regulator on breathing-zone exposure, the EPA on stack emission, the building authority on fire and construction compliance, and the customer’s own ISO and product-certification systems. SBKJ’s engineering documentation is structured to support all of these audit trails simultaneously.

22. Competitive positioning — why local fabrication wins this market

The wire, reinforcing-mesh, fencing and gabion sector is a demanding, technically-specific HVAC market that rewards a particular combination of capabilities, and the competitive logic favours the fabricator who can deliver the full envelope locally. The generic commercial HVAC contractor who treats a wire-and-mesh plant as just another industrial fit-out underestimates the corrosion engineering of the pickling leg, under-sizes the continuous weld-fume LEV, mismatches the duct material to the galvanising and coating plumes, and fails the breathing-zone sampling at commissioning. The specialist who understands the sector — who knows that the weld-fume load is continuous and substantial despite the low per-joint mass, that the pickling plume needs FRP not stainless, that the galvanising plume needs stainless not galvanised, that the coating plume needs condensate management, and that the lube-dust circuit needs deflagration protection — delivers a system that works the first time and is auditable to the full standards stack.

The second competitive dimension is fabrication capability and speed. A plant expansion or a new line cannot wait months for imported ductwork; the fabricator who can produce the rectangular hoods, the spiral mains, the stainless welded ductwork and the custom transitions locally, to specification, on a short lead time, wins the work. This is exactly the capability the SBKJ machine line delivers to an Australian fabricator — the SBAL-V and SBAL-III for the rectangular and heavy-gauge work, the SBFB-1500 and SBTF spiral family for the round mains, the SBSF-1525 and SB-ZF1500 for the welded stainless ductwork, the SBPC1500 for the custom transitions, and the SBLR-600 for the lock-seam branches — so that the fabricator can serve the wire, mesh and fencing sector from a local base with the full production envelope. SBKJ’s position is straightforward: we are the Box Hill North VIC duct-machinery partner that equips Australian fabricators to win and deliver this work, with the machines, the engineering support and the standards-aligned documentation that the sector demands.

23. Closing — SBKJ engineering support for Australian wire, mesh and fencing manufacturing

The Australian reinforcing-mesh, wire, welded-mesh, fencing and gabion sector is a substantial, technically-demanding and growing part of the country’s heavy-manufacturing base, and its ventilation needs are as varied as its processes — resistance-weld fume over the mesh lines, oil mist over the drawing blocks, acid fume over the pickling baths, zinc fume over the galvanising kettles, hydrogen chloride over the coating ovens, and furnace heat over the heat-treatment lines, every one of them with its own exposure standard, duct material and capture strategy. Generic ventilation does not serve this sector; purpose-engineered ductwork, fabricated to the full AS and AS/NZS standards stack and commissioned to the SafeWork workplace exposure standards, does. The SBKJ Group engineering team in Box Hill North VIC is positioned to support Australian fabricators and mechanical contractors serving this sector with machine supply, engineering documentation, commissioning support and ongoing technical advisory across every process zone described in this guide.

We will be exhibiting at ARBS 2026 in Sydney in May with the full SBKJ machine portfolio — SBAL-V, SBAL-III, SBSF-1525, SB-ZF1500, SBFB-1500, SBPC1500, SBLR-600 and SBTF-1500/1602/2020 — plus sector-specific reference samples covering galvanised and stainless weld-fume LEV, the metal-to-FRP pickling transition, the stainless galvanising-kettle hood, and the high-temperature furnace-exhaust transition. Pre-show meetings with Australian wire, mesh, reinforcing and fencing fabricators, their mechanical contractors and machine-OEM partners are scheduled across the week.