Hot Dip Galvanising, Pickling, CGL, Powder Coating, Anodise & Zinc Coating Plant HVAC Duct Guide

1. Why galvanising, pickling and coating HVAC is its own engineering discipline

A galvanising plant is the single most chemically aggressive HVAC environment in Australian heavy industry, with the possible exception of the chlor alkali sector. Every kilogram of steel that walks through an Australian hot dip galvaniser passes through three back to back chemistry environments — alkaline degrease, acid pickle and molten zinc kettle — each releasing fume that destroys conventional galvanised duct in months, sometimes in weeks. Layer powder coating, anodise aluminium and continuous galvanising line operations on top and you have a sector that demands 316L stainless duct at scale, FRP fibreglass duct for the most aggressive acid mist runs, refractory lined steel for the kettle hood, and a fabricator with the production envelope to switch material every metre of a job.

This guide writes against the full breadth of the Australian galvanising, pickling, continuous galvanising line, powder coating, anodise aluminium and zinc coating plant sector. Hot dip galvanising is the headline operation. Industrial Galvanizers, a Boral subsidiary, is the country’s biggest batch hot dip galvaniser by branch network with sites at Hexham NSW, Adelaide, Brisbane, Perth, Melbourne and Newcastle. Korvest ASX:KOV runs a vertically integrated operation in Adelaide SA combining hot dip galvanise with EZYStrut cable tray fabrication, Galvalume sheet handling, pole and pipe galvanising. Galform, part of Trafford Group, runs galvanising at Brisbane and Sydney. Otway Galvanizers VIC, Pacific Galvanizers and Hutchinson Galvanising Wagga Wagga round out the regional batch operations. Above the batch tier sits BlueScope Steel ASX:BSL at Port Kembla NSW, the country’s biggest steelmaker and the only operator of continuous galvanising lines at industrial scale — CGL5, CGL6 and CGL7 produce Truecore structural framing steel, Colorbond pre painted steel, Zincalume and Galvalume aluminium zinc alloy coatings at strip speeds up to 180 m/min. The Western Port VIC coil coating line handles the downstream pre paint and Colorbond paint application. InfraBuild, part of the GFG Alliance Liberty Steel group, operates the Whyalla SA electric arc furnace producing rebar, wire and rod for the construction sector. Together BlueScope and InfraBuild produce essentially all of the country’s primary galvanised feedstock.

Powder coating is the dominant industrial finish on architectural aluminium, fabricated steel and consumer products. Two formulators dominate the Australian powder market: Akzo Nobel Powder Coatings (formerly Interpon, with manufacturing and stocking sites in Sydney, Melbourne, Brisbane, Perth and Adelaide) and Dulux Powder Coatings (DuluxGroup ASX:DLX, with sites at Penrith NSW, Granville, Eastern Creek, Yarrambat VIC, Eagle Farm QLD, Welshpool WA and Wingfield SA). Jotun Powder Coatings, Tiger Coatings, IGI Coatings and PPG Industries Australia round out the formulator tier. Below the formulators sits a national network of several hundred powder coat applicators ranging from architectural specialists serving Capral Aluminium and AWS Architectural Window Systems through to general jobbing coaters serving fabricated steel and consumer products. The Australian Powder Coaters Association APCA is the industry body for the applicator tier.

Anodise aluminium is the third major finish, with Capral Aluminium ASX:CAA and AWS Architectural Window Systems leading the architectural extrusion segment. The anodise chemistry tree has historically included chromic acid anodise (CAA), sulfuric acid anodise (SAA), boric sulfuric anodise (BSAA) and tartaric sulfuric anodise (TSA). The transition from Cr VI bearing CAA to non chromate TSA and BSAA is one of the most significant chemistry shifts in the Australian metal finishing sector in the last decade, driven by the IARC Group 1 carcinogen classification of Cr VI and the SafeWork Australia exposure standard reduction to 0.05 mg/m3 in 2024.

Across this entire sector, coatings ductwork must survive five demands simultaneously: chloride pitting resistance (HCl pickle mist, ZnCl2 flux fume), sulfate acid resistance (sulfuric pickle mist, sulfuric acid anodise mist, sulfur dioxide from coke combustion at the kettle), high temperature resistance (450 degC molten zinc kettle, 200 degC powder cure oven, 750 to 850 degC CGL annealing furnace), dust deflagration resistance (powder coat Zone 22 under AS 3957 and AS/NZS 60079.10.2, aluminium fines from Galvalume CGL trim under NFPA 484), and respiratory hazard control (ZnO fume galvanising flu, HCl mist, sulfuric mist, isocyanate from polyurethane powder coat cure, Cr VI legacy passivation, HF from aluminium pre paint etch). Each is manageable in isolation. Together they explain why a generic commercial fabricator treating a galvaniser as just another industrial job replaces duct twice in the first year and walks away from the second contract.

This guide walks every major coatings process, explains what changes about the ductwork, and 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. The sector is large, durable, capital intensive and consolidating — a fabricator with the right machine fitment, the right material selection knowledge and the right standards understanding can lock in 10 to 20 year service contracts with the major operators.

2. The Australian regulatory stack — AS 1668.2, AS 4254, AS/NZS 4680, AS/NZS 60079, AS 1530.4, AS 1885, AS 3957, NFPA 484, NFPA 660, NFPA 86

Coatings HVAC in Australia sits at the intersection of more than a dozen overlapping standards and codes. Ignoring any one of them is a notice of non compliance from SafeWork Australia, the state EPA, or both, waiting to happen. The standards stack splits into building code compliance, occupational health exposure compliance, hazardous area electrical compliance, dust explosion compliance, and process specific galvanising and coating standards.

2.1 AS 1668.2 — mechanical ventilation for buildings

AS 1668.2 is the umbrella mechanical ventilation standard. Galvanising plants, powder coat shops and anodise operations all fall under NCC Class 8 industrial occupancy; Table 4 of AS 1668.2 sets minimum extract rates for metal cleaning, plating, painting, baking and finishing. In practice a coatings operation seldom gets close to the minimum — local exhaust ventilation (LEV) at each individual fume and dust source drives total exhaust well above the building volume figure. Where AS 1668.2 matters most is the make up air requirement: every cubic metre extracted must be replaced by tempered, filtered, controlled velocity supply air, keeping the kettle floor at neutral or slightly positive pressure relative to office and laboratory zones, and preventing furnace stack backdraft. Australian galvaniser experience consistently shows that under sized make up air is the single biggest HVAC retrofit issue: the operator turns up the kettle hood extract, the building goes negative, the kettle stack backdrafts, zinc fume floods the operator floor.

2.2 AS 4254 — sheet metal 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. Most galvanising and powder coat HVAC sits inside AS 4254 ranges. Kettle hood mains in their hot section run beyond AS 4254 and require purpose engineered heavy gauge stainless construction; AS 4254 picks up again on the cool side downstream of the air cooler, the wet scrubber or the baghouse. Powder coat duct work, anodise duct work and pickle line cool side duct work all sit fully inside AS 4254 normal practice.

2.3 AS/NZS 4680 — hot dip galvanising, THE STANDARD

AS/NZS 4680 is the master Australian standard for hot dip galvanised (zinc) coatings on fabricated ferrous articles. Every Australian batch galvaniser including Industrial Galvanizers, Korvest, Galform, Otway, Pacific and Hutchinson sells coating to AS/NZS 4680. The standard specifies: minimum coating thickness by article mass (50 micron for articles below 1.5 mm, 70 micron for 1.5 to 3 mm, 85 micron for 3 to 6 mm, 100 micron for above 6 mm), bath composition (99.99% Zn minimum), surface preparation grade (Sa 2.5 abrasive blast or chemical pickle), post dip cooling, post dip passivation chemistry (chromate, phosphate or chromate free Cr III), and final inspection. From an HVAC perspective AS/NZS 4680 drives three engineering requirements: kettle hood with continuous extract sized at 80 to 100 ACH over the bath area, flux dip extraction, and passivation extraction. Compliance with AS/NZS 4680 plus AS 1885 plus AS/NZS 4801 is the regulatory package the galvaniser presents to SafeWork Australia state inspectors.

2.4 AS 1885 — occupational health in metal working workplaces

AS 1885 (historic standard, still cited in industry safety practice) and the current SafeWork Australia codes of practice cover galvaniser specific occupational safety — zinc fume control at the kettle, acid mist control at the pickle line, fume control at the flux dip, dust control at powder coat overspray, and protection against acute exposure to ZnCl2, HCl, sulfuric mist and isocyanate. AS 1668.1 covers fire and smoke management with fire dampers at zone boundaries and smoke control dampers where production zones connect to office or evacuation routes. AS 1851 covers routine service and maintenance of fire protection equipment including fire dampers, smoke dampers and ductwork penetrations. AS 1530.4 covers fire resistance testing of building elements including fire rated ductwork penetrations between kettle building, pickle building, powder coat shop and office zones.

2.5 AS 3957 — dust hazard areas, the powder coat standard

AS 3957 is the Australian dust hazard standard and is critically applicable to powder coat shops. Powder coat overspray accumulation in the booth, in the duct, in the cyclone and at the filter is a Zone 22 dust hazard area under AS/NZS 60079.10.2 (occasional explosible dust concentration). AS 3957 mandates dust hazard area zoning, drives AS/NZS 60079.10.2 electrical equipment selection downstream, and forces the conductive bonding and grounding of every metre of powder coat duct work. The minimum ignition energy MIE of polyester powder is approximately 10 to 30 mJ, low enough to ignite from static discharge if the duct is not properly bonded. The deflagration index Kst of polyester powder ranges from 50 to 200 bar.m/s depending on particle size, classified as St1 or St2 explosion class. Baghouse and cartridge filter selection downstream of the powder booth must include engineered deflagration vents sized per AS 3957 plus isolation flap valves between filter and inbound duct.

2.6 AS/NZS 60079 — explosive atmospheres

AS/NZS 60079 is the hazardous area classification standard. Coatings operations trigger AS/NZS 60079.10.2 dust classification anywhere combustible dust accumulates (Zone 20 continuous, Zone 21 occasional, Zone 22 unlikely), and trigger AS/NZS 60079.10.1 gas classification anywhere combustible gas is present (Zone 1, Zone 2). Four specific coatings locations almost always become Zone 1: the pickle bath canopy hood (HCl vapour at 16% concentration), the CGL annealing furnace exhaust under H2 plus N2 atmosphere, the powder cure oven during solvent burn off at start up, and the LPG burner area on any gas fired kettle, oven or annealing furnace. Powder coat booth and powder coat duct work are Zone 22 dust. Cadmium electroplate and cyanide alkaline electroplate lines (legacy operations being phased out) trigger Zone 1 from HCN risk plus the toxic exposure controls. Hazardous area zoning drives Ex rated electrical equipment requirements for fans, motors, instrumentation and duct mounted sensors throughout the affected zones.

2.7 NFPA 484 — combustible metals

NFPA 484 is the US National Fire Protection Association standard for combustible metals, referenced extensively by Australian insurance underwriters and used as the de facto engineering reference where AS standards are silent. NFPA 484 applies to coatings operations primarily through aluminium fines from Galvalume continuous galvanising trim cutting, from Capral Aluminium extrusion handling, and from aluminium pre paint etch. Aluminium dust is water reactive when wet and hot: a damp aluminium fines pile in a baghouse is one of the most dangerous fire hazards in any coatings shop. NFPA 484 mandates wet collection extraction for fine aluminium dust, prohibits dry baghouses without engineered deflagration venting, and sets bonding, grounding and isolation damper requirements that prevent a baghouse fire from propagating back into the ductwork main. Magnesium dust ignites at lower concentration than aluminium and is harder to extinguish; magnesium powder coat substrates require sealed wet bath collectors with inert gas blanketing.

2.8 NFPA 660 — combustible dust, 2025 consolidation

NFPA 660 is the 2025 consolidation standard merging the previous NFPA 61, 484, 654 and 664 dust standards into a single document. The consolidation applies the same engineering principles across dust types but with updated combustible dust analysis requirements at facility level. Australian coatings operations adopting NFPA 660 in 2026 face revised dust hazard analysis documentation, updated bonding and grounding requirements, and tightened isolation valve specifications between baghouse and inbound duct. Powder coat booth installation post 2025 references NFPA 660 directly in the project documentation handed to the insurer.

2.9 NFPA 86 — industrial ovens and furnaces

NFPA 86 covers the hot dip galvanise kettle at 450 degC, the CGL annealing furnace at 750 to 850 degC, the Zincalume zinc aluminium pot at 470 degC, and the powder cure oven at 200 degC. Exhaust topology under NFPA 86 includes LEL monitoring at every gas fired burner, purge cycles before lighting, explosion venting on the oven shell, dedicated exhaust risers separate from general factory exhaust, and burner management systems with redundant flame supervision. The CGL annealing furnace at BlueScope Port Kembla operates under H2 plus N2 reducing atmosphere, the highest hazard burner management situation in any Australian coatings operation, and NFPA 86 compliance is non negotiable.

2.10 AS/NZS 4801 OHS, ISO 45001, ISO 9001, ISO 14001

AS/NZS 4801 (the Australian OHS management standard, integrated with ISO 45001) sets the systemic OHS framework that coatings HVAC documentation feeds into — LEV maintenance records, air monitoring data, respiratory protection programs, hearing conservation at powder booth fans, and combustible dust risk assessment. ISO 9001 quality management is mandatory for every BlueScope, InfraBuild, Korvest, Industrial Galvanizers and Capral feed contractor. ISO 14001 environmental management drives stack emissions documentation, scrubber discharge documentation, and waste stream documentation for zinc dross, zinc ash, spent pickle liquor and powder coat overspray waste.

2.11 AS/NZS 1715 + AS/NZS 1716 — respiratory protective equipment

AS/NZS 1715 sets the selection, use and maintenance of respiratory protective equipment. AS/NZS 1716 sets the performance and testing of RPE. Together they govern the respiratory protection program that backs up engineering HVAC control at the galvanise kettle, the pickle line, the powder booth and the anodise station. The hierarchy of control under both standards is engineering first (LEV duct work), administrative second (rotation, training, signage), then RPE last. The respiratory protection program documentation supports the LEV system design — if the LEV is correctly sized, RPE is a backup; if the LEV is undersized, RPE becomes the primary control which is unacceptable under AS/NZS 4801.

2.12 SafeWork Australia exposure standards — the chemistry driven sizing inputs

SafeWork Australia’s workplace exposure standards (WES) are the regulatory inputs that drive LEV capture velocity and ductwork sizing. The coatings relevant standards are extensive and worth reading as a single block because they collectively explain why coatings HVAC is dimensioned the way it is:

• Zinc oxide fume (ZnO): 5 mg/m3 TWA, STEL 10 mg/m3. THE killer at the hot dip galvanise kettle. Drives kettle hood sizing, building extract sizing and respiratory protection. Causes metal fume fever (galvanising flu) on STEL exceedance.
• Zinc chloride fume (ZnCl2): 1 mg/m3 TWA. From flux dip salt decomposition at the kettle face. Acutely irritating to respiratory tract and skin.
• Ammonium chloride fume (NH4Cl): 10 mg/m3 TWA. From flux dip double salt decomposition at the kettle face.
• Hydrochloric acid mist (HCl): 5 ppm STEL. From hydrochloric acid pickle bath at 16% concentration, 30 to 50 degC. The dominant pickle line exposure.
• Sulfuric acid mist (H2SO4): 1 mg/m3 STEL. From sulfuric pickle bath at 18% concentration, 60 to 80 degC. Historic chemistry, still in service at older lines and at some pre paint etch operations.
• Nitric acid mist (HNO3): 4 ppm STEL. From Galvanneal flux, stainless pickle and passivation. Strong oxidising acid, NOx fume formation if mishandled.
• Hydrogen fluoride (HF): 1.8 ppm STEL. From aluminium pre paint etch, stainless pre paint etch, mixed acid pickling. Extraordinarily corrosive to silica refractory, to galvanised duct and to lung tissue at low concentration.
• Sodium hydroxide / potassium hydroxide mist (NaOH, KOH): 2 mg/m3 ceiling. From alkaline degrease stage at 60 to 80 degC. Corrosive to skin and respiratory tract.
• Ammonia (NH3): 25 ppm STEL. From cooling tower bleed, NH4Cl flux decomposition, nickel cellhouse on electroplate lines.
• Carbon monoxide (CO): 30 ppm STEL. From LPG fired kettle burners, oxygen poor combustion, CGL annealing furnace H2/N2 atmosphere.
• Aluminium (inhalable): 1 mg/m3 TWA respirable. From Galvalume CGL trim, Capral Aluminium handling, anodise pre paint dust.
• Cadmium (Cd): 0.01 mg/m3 STEL. From legacy cadmium electroplate (being phased out across all Australian lines, IARC Group 1 carcinogen).
• Chromium hexavalent (Cr VI): 0.05 mg/m3. From chromate conversion coating, chromic acid anodise CAA (being phased out), chromate sealing of anodise (being phased out). The phase out to Cr III, TSA, BSAA and SAA non chromate processes is the most significant chemistry shift in the Australian coatings sector in a decade. IARC Group 1 carcinogen.
• Nickel (Ni inhalable): 1 mg/m3. Insoluble Ni 0.1 mg/m3. From nickel electroplate, stainless pickle, alloy steel handling.
• Lead (inorganic): 0.05 mg/m3. From legacy leaded brass handling and some legacy passivation chemistries.
• Manganese (Mn): 0.2 mg/m3. From welding fume on fabricated steel pre dip and powder coat substrate welding.
• Iron oxide fume (Fe2O3): 5 mg/m3. From steel descale at pickle, welding fume, dross skim at the kettle.
• Cyanide (HCN): 5 ppm STEL. From legacy alkaline cyanide electroplate (being phased out across all Australian lines). Acute toxin.
• Formaldehyde: 1 ppm STEL. From phenol formaldehyde (PF) resin powder coat systems and epoxy primer cure outgassing.
• MDI/TDI isocyanates: 0.005 ppm STEL. From polyurethane powder coat cure outgassing. Acute respiratory sensitiser and suspected endocrine disruptor; being phased from formulator product lines.
• Polyester / epoxy / polyurethane powder dust: 5 mg/m3 (treated as nuisance dust under particulate general inhalable). The bulk powder coat overspray loading.
• VOC general (solvent and thinner): Mixed exposure assessment. From pre paint solvent cleaner, anodise dye solvents and powder coat pre treatment.
• Particulate (general inhalable): 10 mg/m3. Whole of air dust marker.
• Methane (CH4): 1.25% LEL. LPG and natural gas fuel for kettle, CGL annealing furnace and powder cure oven.

Every dust and fume LEV branch in a coatings operation has to keep the operator’s breathing zone air below the relevant WES. Where multiple contaminants are present (Zn fume plus HCl mist plus Fe2O3 at the kettle flux dip transition, or epoxy powder plus polyurethane isocyanate at the powder cure oven), the additive mixture rule applies and the LEV must be sized to the lowest practical fraction. This is the calculation that drives capture velocity, transport velocity, branch sizing and main sizing across every coatings duct system.

3. Process zones — the coatings line end to end

The most reliable way to specify coatings HVAC is to walk the process flow. Every Australian galvanising line maps to a variant of the same end to end sequence: steel cleaning and degrease, rinse and cascade, acid pickle and descale, flux dip, dry pre dip, hot dip galvanise kettle, post dip quench, passivation, and inspection. The continuous galvanising line CGL adds an entry section, an annealing furnace, a snout, a zinc pot and a tower cooler. Powder coat adds a pre treatment, an electrostatic spray booth, a cure oven and a cooldown. Anodise adds a chemistry sequence of alkaline etch, desmut, anodise tank, dye tank and sealing. Each station has its own characteristic fume chemistry, temperature, capture velocity and material requirement.

3.1 Steel cleaning and degrease — alkaline NaOH plus KOH plus anionic surfactant

Stage 1 of any galvanising line is alkaline cleaning. The fabricated steel article is immersed in a hot alkaline bath at 60 to 80 degC containing sodium hydroxide NaOH, potassium hydroxide KOH and anionic surfactant for oil, grease and shop soil removal. The chemistry is corrosive but not aggressively volatile — the dominant exposure is alkaline mist from boiling bath surface, captured by canopy hood at 1.0 to 1.5 m/s face velocity, ducted in 316L stainless to a wet scrubber or simply to a packed bed alkaline scrubber for dust removal. The duct work here is 316L at 1.2 mm gauge for the canopy hood and immediate downstream main, transitioning to FRP if scrubber inlet runs cool. SafeWork Australia WES for NaOH and KOH mist is 2 mg/m3 ceiling.

3.2 Rinse and cascade — DI deionised, RO and conductivity controlled

Between every chemistry stage in a modern galvanising or anodise line is a rinse stage. The article passes through one or more rinse tanks — cascade rinse, where fresh water enters the cleanest tank and overflows back through progressively dirtier tanks — with deionised (DI) or reverse osmosis (RO) water for high spec lines. Rinse stages are HVAC light: little fume, low temperature, low corrosion. Standard 304 stainless or even painted carbon steel duct work suffices. The HVAC envelope here is about humidity control: a poorly designed rinse station floods the surrounding building with moisture causing condensation on adjacent ductwork. The fix is a localised exhaust hood at each rinse tank pulling 0.3 to 0.5 m/s face velocity, ducted to a moisture eliminator and back to atmosphere.

3.3 Pickling and acid descale — H2SO4 sulfuric or HCl hydrochloric

Stage 2 is the pickle line, the chemistry stage where mill scale and rust are dissolved from the steel surface ready for fluxing and galvanising. Two chemistry options:

Sulfuric acid pickle (H2SO4 at 18% concentration, 60 to 80 degC): The historic chemistry, still in service at older lines and at some pre paint etch operations. Slower scale removal than HCl, higher energy demand to heat the bath, but lower ventilation load per square metre of bath surface because sulfuric is less volatile than hydrochloric. The dominant exposure is sulfuric acid mist (SafeWork Australia STEL 1 mg/m3). Canopy hood ducted in 316L stainless or FRP at 0.5 to 0.8 m/s face velocity, terminating at a packed bed wet scrubber with caustic soda neutralisation. Spent pickle liquor is iron sulfate FeSO4 with high iron load; treatment is by lime neutralisation and iron precipitation, with the iron sludge cake going to controlled landfill or to specialist pickle liquor recovery contractors.

Hydrochloric acid pickle (HCl at 16% concentration, 30 to 50 degC): The modern chemistry. Faster scale removal, lower energy demand, easier acid recovery, and lower toxicity than sulfuric. The dominant exposure is HCl mist (SafeWork Australia STEL 5 ppm) and the bath releases significantly more vapour per square metre of surface than sulfuric. Canopy hood ducted in 316L stainless minimum 1.5 mm gauge or FRP at 0.7 to 1.0 m/s face velocity, terminating at a venturi or packed bed wet scrubber with caustic soda neutralisation. Spent pickle liquor is iron chloride FeCl2/FeCl3 which is recoverable: many modern Australian galvanisers send spent pickle liquor to a regional recovery contractor who oxidises FeCl2 to FeCl3 for sale to water treatment plants and pigment manufacturers, closing the loop. The acid mist extraction is the most aggressive HVAC service in any galvaniser. 316L pitting failure inside 24 months without proper passivation is common. FRP fibreglass duct with vinyl ester resin laminate is the durable alternative for the long horizontal runs and the scrubber inlet, with 316L reserved for the immediate canopy and the high temperature sections.

Pickling line LEV is the second largest individual subsystem in any Australian galvaniser (after the kettle building extract). Industrial Galvanizers Hexham NSW and Korvest Adelaide SA both run pickle lines at over 30,000 m3/h extract through 800 to 1200 mm spiral 316L mains and 1500 to 2000 mm FRP mains transitioning to the scrubber stack.

3.4 Flux dip — ZnCl2 plus NH4Cl double salt

Stage 3 is the flux dip. The cleaned, descaled article is immersed in a hot flux bath (60 to 80 degC) containing zinc chloride ZnCl2 plus ammonium chloride NH4Cl double salt. The flux coats the article surface, drying as the article exits the bath, and reacts with both the steel surface and the molten zinc at the kettle face to ensure proper metallurgical bonding. The flux dip releases ZnCl2 fume (WES 1 mg/m3) and NH4Cl fume (WES 10 mg/m3) at the bath surface, with the heaviest emission during article entry and exit. Canopy hood at 0.7 to 1.0 m/s face velocity, ducted in 316L stainless to a dry scrubber (often a fabric filter loaded with sodium bicarbonate to neutralise residual HCl from ZnCl2 decomposition) or to a small wet scrubber. The flux dip extraction is a relatively modest individual subsystem but is critical because flux fume is the primary precursor to ZnO fume at the kettle — well controlled flux dip extraction reduces kettle fume load by 20 to 30%.

3.5 Dry pre dip — 100 to 110 degC

Stage 4 is the dry pre dip, a heated chamber or conveyor at 100 to 110 degC where the flux coated article is dried before entering the molten zinc. The chamber removes residual water from the flux coating, preventing flash evaporation and zinc splash when the article hits the molten kettle. The HVAC demand is modest: a small extract at the chamber exit removes water vapour and residual NH4Cl fume, ducted in 316L stainless to a moisture eliminator and back to atmosphere or to the flux dip scrubber. The chamber itself is heated by waste heat from the kettle or by dedicated LPG burner.

3.6 Hot dip galvanise HDG kettle — molten zinc 450 to 460 degC

Stage 5 is the headline operation: the molten zinc kettle. The kettle is a refractory lined or ceramic crucible holding 50 to 300 tonnes of molten zinc at 450 to 460 degC, with the zinc maintained at 99.99% purity per AS/NZS 4680. Kettle dimensions vary by site: small kettles at jobbing galvanisers are 1.5 m wide by 6 to 8 m long by 2 m deep; large kettles at Industrial Galvanizers Hexham, Korvest Adelaide and Galform Brisbane are 3 to 3.5 m wide by 10 to 15 m long by 2.5 to 3 m deep, holding 300 to 500 tonnes of molten zinc.

Each article enters the kettle through the flux layer floating on the bath surface, displaces zinc into the kettle, sits submerged for 1 to 6 minutes depending on article mass and complexity, and exits with a 50 to 200 micron zinc coating per AS/NZS 4680. As the article enters and exits, residual flux on the surface decomposes in milliseconds, generating dense white fume rich in ZnCl2, NH4Cl smoke, ZnO sub micron particulate and trace HCl. The fume load peaks during article entry and exit and falls to background during the submerged phase. Total ZnO fume emission from a large kettle running at 80% utilisation can exceed 200 kg/day.

Kettle hood design is the central HVAC engineering problem at any Australian galvaniser. Three approaches are in service:

Continuous full coverage hood: A push pull hood covering the entire bath surface with extract on one long side and supply curtain on the other, drawing 80 to 100 ACH over the bath area. Construction is heavy gauge 309S or 310S stainless steel sheet (1.6 to 3 mm gauge) with refractory lining on the underside facing the bath. The heavy stainless is needed because the underside operates at 250 to 400 degC service temperature for years on end. Downstream of the kettle area the duct cools rapidly and transitions to 316L at 1.5 to 2.0 mm gauge.

Enclosed kettle: Modern Australian galvanisers including Korvest and the larger Industrial Galvanizers branches use enclosed kettle designs with full perimeter walls and a top opening for jig entry and exit. The enclosure is built in 1.6 mm heavy gauge GAL galvanised sheet (counterintuitively) for the outer skin because it does not contact the hottest fume directly, with a refractory lined inner shell for the hot section. The enclosure approach reduces total exhaust volume by 40 to 60% versus open kettle, drives down operator zinc exposure, and gives the engineering team a defensible AS/NZS 4680 compliance position.

Push pull lip exhaust: Lower cost retrofit option for existing open kettles. Lip exhaust slot hood along one long side of the kettle drawing through 316L slot duct. Effective for smaller kettles but does not provide the operator exposure protection of the enclosed approach for large kettles.

Downstream of the kettle the fume passes through an air cooler (heat exchanger reducing temperature to below 120 degC), a primary cyclone or impingement separator (knocking out particulate dross), a baghouse with PTFE membrane filter (capturing ZnO sub micron particulate), and a stack to atmosphere with continuous emissions monitoring per state EPA licence. Total kettle exhaust at a large modern galvaniser exceeds 200,000 m3/h. The building general extract supplements the kettle hood at 4 to 6 ACH over the kettle bay floor area.

3.7 Post dip quench — water plus air plus passivate

Stage 6 is the post dip quench. The freshly galvanised article exits the kettle at 450 degC, drips excess zinc back into the kettle for 30 to 60 seconds, then enters the quench. Three quench options: water quench (immediate cooling to 100 degC by water spray or immersion, releases significant steam plumes), air quench (slow controlled cooling under fans, used for high spec articles where rapid quench would cause thermal stress cracking), and chromate or phosphate passivation quench (combined cooling and post dip chemical treatment). Water quench releases steam plus residual zinc fume captured by canopy hood ducted in 316L stainless to a moisture eliminator and back to atmosphere. Air quench is HVAC light with general building extract sufficing. Chromate passivation quench uses Cr VI or Cr III chemistry — the Cr VI option is being phased out across all Australian galvanisers in favour of Cr III conversion coatings and phosphate passivation, with HVAC implications for the LEV downstream.

3.8 Passivation — Cr VI legacy, Cr III modern, phosphate

Post quench passivation delays the formation of zinc oxide white storage stain on freshly galvanised steel. Three chemistries:

Chromate passivation Cr VI: Sodium dichromate or chromic acid bath at 30 to 50 degC. The yellow passivation seen on older galvanised steel. Cr VI exposure (SafeWork Australia WES 0.05 mg/m3, IARC Group 1 carcinogen). Being phased out across all Australian galvanisers under SafeWork pressure plus customer specification pressure. LEV at the bath requires dedicated 316L stainless with HEPA polish on the baghouse and continuous Cr VI stack monitoring.

Trivalent chromium Cr III: The modern chromate replacement. Cr III is not classified by IARC as Group 1 and is significantly less hazardous than Cr VI, with a SafeWork Australia WES of 0.5 mg/m3 (10x higher than Cr VI). The chemistry gives equivalent corrosion delay performance to Cr VI chromate and is dropping into new lines and refurbished lines across the Australian sector. HVAC at a Cr III passivation station uses standard 316L LEV without HEPA polish.

Phosphate passivation: Zinc phosphate or manganese phosphate conversion coating. Standard pre paint preparation chemistry, also used as standalone passivation. HVAC is light: low fume, low corrosion, painted carbon steel duct work suffices.

3.9 Continuous galvanising line CGL — BlueScope Port Kembla CGL5, CGL6, CGL7

The continuous galvanising line CGL is a different beast from a batch HDG operation. CGL runs flat steel strip in coil at 100 to 180 m/min through a continuous in line process. BlueScope Steel at Port Kembla NSW operates three CGLs: CGL5, CGL6 and CGL7, producing Truecore structural framing steel for the residential and commercial construction sectors, Colorbond pre painted steel for roofing and cladding, Zincalume aluminium zinc alloy coating (55% Al, 43% Zn, 1.5% Si) and Galvalume (the same chemistry under a different brand). The Western Port VIC coil coating line handles the downstream pre paint and Colorbond paint coating.

The CGL HVAC envelope splits into four sub envelopes:

Entry, degrease and pickle section: Strip enters from the coil pay off, runs through an alkaline degrease, electrolytic cleaning section, and HCl pickle. HVAC is the alkaline mist and HCl mist controls described in section 3.1 and 3.3 above, but at higher continuous emission rate than a batch operation. 316L stainless mains, FRP scrubber inlet, central wet scrubber stack.

Annealing furnace: Strip enters the annealing furnace at 750 to 850 degC under reducing H2 plus N2 atmosphere (typically 5 to 20% H2 in N2). The furnace removes residual surface oxide and prepares the strip for zinc adhesion. NFPA 86 compliance is mandatory: explosion vented furnace shell, LEL monitoring on H2 supply, burner management with redundant flame supervision, dedicated explosion vented exhaust riser. The exhaust gas (post H2 combustion) is hot N2 plus H2O at 500 to 700 degC, ducted in heavy gauge 309S stainless to a heat exchanger and stack.

Zinc pot or Zincalume pot: Strip enters molten zinc at 460 degC (or molten Zincalume at 470 to 480 degC) via a snout that seals the annealing furnace atmosphere from the bath surface. Air knives above the bath control coating thickness, typically to 0.4 to 1.2 mm strip with Z275 (275 g/m2 zinc both sides) or AZ150 (150 g/m2 alloy both sides) coating. The pot HVAC is identical chemistry to a batch kettle (ZnO fume) but at higher continuous emission rate. Heavy gauge 309S stainless kettle hood ducted to baghouse and stack.

Cooling tower and tension leveller: Strip exits the pot, passes through air cooling jets, then a hot tension leveller for flatness control, then minispangle treatment for surface appearance. HVAC here is general building extract plus mist eliminator at the air cooling jets. Downstream of cooling, the strip goes to recoiling, trim cutting (generating aluminium and zinc fines under NFPA 484), and packaging.

Total CGL exhaust exceeds 500,000 m3/h split across these four envelopes. The duct work fabrication challenge is the sheer volume of heavy gauge stainless and the long runs — a single CGL annealing furnace exhaust main runs 50 to 80 m in 1500 to 2000 mm 309S spiral. Only a fabricator with the SBFB-1500 spiral tubeformer plus the SB-ZF1500 longitudinal stitch welder for heavy gauge stainless can handle this scope.

3.10 Powder coating — pretreatment, electrostatic spray, cure oven

Powder coating runs in three stages:

Pretreatment: The substrate (galvanised steel, anodised aluminium, raw fabricated steel, Capral aluminium extrusion) is cleaned and chemically pre treated before powder application. Pretreatment chemistry varies: zinc phosphate conversion for general steel, iron phosphate for lower spec steel, chromate or non chromate conversion for aluminium. The pretreatment line is a 3 to 7 stage spray tunnel with alkaline degrease, rinse, conversion coat, rinse, optional sealer and final DI rinse. HVAC at the pretreatment tunnel is moisture control plus alkaline mist extraction plus optional Cr VI legacy LEV where chromate conversion is still in service.

Electrostatic spray booth: The pretreated substrate is conveyed into the powder spray booth where electrostatically charged powder (epoxy, polyester, polyurethane, epoxy polyester hybrid) is applied via corona or tribo charge guns. Powder utilisation is 95 to 98% through powder recovery via the booth cyclone and filter cartridge bank, feeding recovered powder back to the gun supply. Booth airflow is 0.5 to 1.0 m/s face velocity at the booth opening with controlled extract to maintain booth pressure slightly negative relative to the surrounding building. Booth construction is medium gauge galvanised carbon steel sheet to AS 4254 medium pressure with conductive bonding throughout per AS/NZS 60079.10.2 Zone 22 dust hazard compliance. The booth interior surfaces are polished or coated for easy cleanout between colour changes.

Cure oven: The coated substrate is conveyed into a cure oven at 200 degC for 20 minutes (epoxy, polyester) or 180 degC for 15 minutes (low temperature polyurethane). The cure oven outgasses VOC from the powder polymerisation reaction including trace formaldehyde from phenol formaldehyde resin systems, trace isocyanate from polyurethane chemistry (SafeWork STEL 0.005 ppm for MDI/TDI), and general aliphatic and aromatic VOC. Cure oven HVAC is a separate branch from the spray booth, in heavy gauge mild steel insulated duct or aluminised steel at 1.6 mm gauge, terminating at an activated carbon adsorber or a thermal oxidiser (regenerative thermal oxidiser RTO is the standard solution for high throughput lines). The cure oven shell is explosion vented per NFPA 86 with LEL monitoring on the gas burner.

3.11 Powder coat booth — controlled airflow and overspray collection

The powder coat booth itself is one of the most carefully engineered HVAC envelopes in any Australian factory. Three booth design philosophies are in service:

Cartridge filter booth: Standard medium volume booth for jobbing applicators. Booth extract draws through a bank of cartridge filters (cellulose plus polyester media, 80% efficiency at 1 micron) capturing overspray powder. Recovered powder discharges from the cartridge cleaning pulse jet into a collection hopper for reuse. Booth extract terminates at HEPA polish before discharge to atmosphere. Duct construction is medium gauge galvanised spiral with conductive bonding.

Cyclone plus cartridge filter booth: High volume booth for architectural and high throughput applicators. Booth extract first passes through a primary cyclone (capturing the bulk of recovered powder in a single colour collection hopper), then through cartridge filters for sub micron polish. The cyclone gives cleaner powder for direct reuse with minimal cross contamination. Duct construction includes the cyclone inlet at 1.0 to 1.2 mm galvanised heavier gauge, and longer trunk mains where the SBFB-1500 spiral tubeformer is the production solution.

Belt filter or cardboard filter booth: Low cost throwaway booth for short runs or for high colour change frequency where powder recovery is not economic. Disposable belt or cardboard filter captures overspray with no recovery; the spent filter is replaced after each shift or each colour change. HVAC is simpler with single stage extract through the filter to HEPA polish to stack.

All three booth designs share the same conductive bonding requirement: every duct section bonded across flanges with copper grounding straps, all metalwork bonded to building earth, and powder collection equipment bonded and grounded per AS/NZS 60079.10.2 plus AS 3957 plus NFPA 660. The minimum ignition energy of polyester powder is approximately 10 to 30 mJ, low enough to ignite from static discharge if the bonding is not properly maintained.

Spray on / spray off conveyor design moves the substrate through the booth on a chain or monorail conveyor. The conveyor passes through the booth opening, through the cure oven, and back out for offload. The booth opening seals (often hanging strip curtains plus airflow) maintain booth pressure and prevent powder migration into the surrounding building. The conveyor itself is grounded throughout.

3.12 Anodise aluminium — SAA, TSA, BSAA non chromate

Anodise aluminium produces a controlled thickness of aluminium oxide on the substrate surface for corrosion resistance, dye uptake or substrate hardness. Capral Aluminium ASX:CAA and AWS Architectural Window Systems are the major architectural anodise operators in Australia. Four chemistry options are in service:

Sulfuric acid anodise SAA: The standard architectural process. Sulfuric acid bath at 18 to 20% concentration, 20 degC, with the article connected as the anode. Anodise thickness 5 to 25 micron depending on duty. SafeWork Australia STEL 1 mg/m3 for sulfuric mist. LEV at 316L stainless or FRP fibreglass at 0.5 to 0.8 m/s face velocity, packed bed wet scrubber with caustic neutralisation. SAA is the dominant Capral chemistry.

Tartaric sulfuric anodise TSA: Sulfuric acid bath plus tartaric acid additive, replacing chromic acid anodise CAA for aerospace and defence aluminium. Lower environmental impact than CAA, no Cr VI exposure, equivalent fatigue performance for aerospace. HVAC envelope is essentially identical to SAA.

Boric sulfuric anodise BSAA: Sulfuric acid plus boric acid additive, the other major CAA replacement for aerospace. HVAC envelope identical to SAA.

Hard anodise: Sulfuric acid bath at 0 to 5 degC with higher current density, producing 25 to 100 micron oxide for wear resistant applications (industrial machinery, ammunition components, hydraulic cylinders). Higher exhaust volume due to bath cooling and aggressive electrolyte. HVAC at 316L plus FRP with cooled scrubber loop.

Each anodise tank is preceded by an alkaline degrease, an alkaline etch (NaOH at 60 degC producing the matte surface), a desmut (HNO3 or proprietary mixed acid removing alloying element residues from the etch), and a rinse. Each is a separate LEV branch — NaOH mist at the etch tank, HNO3 mist at the desmut, mixed acid mist where mixed chemistries are used. Post anodise the article passes through a rinse, an optional dye tank (for colour anodise), and a sealing tank (hot DI water or nickel acetate or, historically, dichromate chromate seal). The chromate seal is being phased out across Capral and AWS in favour of nickel acetate and hot water sealing.

3.13 Electroplate — Cr, Ni, Cu, Zn, Cd phasing

Electroplate operations sit alongside galvanise and anodise in the broader Australian metal finishing sector, often co located within a single facility. The major chemistries are:

Chromium plate: Cr VI based decorative and hard chrome electroplate. Highest risk plating chemistry. Being phased out under SafeWork pressure and customer specification pressure. LEV at 316L stainless with HEPA polish and Cr VI continuous stack monitoring per state EPA licence.

Nickel plate: Nickel sulfate plus nickel chloride plus boric acid (Watts bath) or nickel sulfamate. SafeWork WES 1 mg/m3 inhalable Ni, 0.1 mg/m3 insoluble Ni compounds. LEV at 316L stainless to a packed bed wet scrubber.

Copper plate: Acid copper sulfate or cyanide alkaline copper. The cyanide variant is being phased out. LEV at 316L stainless.

Zinc electroplate: Alternative to hot dip galvanising for thin coatings (5 to 20 micron) on small fabricated articles. Alkaline cyanide zinc (being phased out) and acid zinc chloride (modern chemistry). LEV at 316L stainless.

Cadmium electroplate: Legacy chemistry, IARC Group 1 carcinogen. Cd WES 0.01 mg/m3 STEL. Being phased out across all Australian lines under aerospace prime customer pressure and SafeWork pressure. LEV at 316L stainless with HEPA polish and Cd continuous stack monitoring.

3.14 Zinc dross, zinc ash, spent pickle liquor — waste management

Every galvanising operation generates three primary waste streams that drive ancillary HVAC requirements:

Zinc dross: Iron zinc intermetallic compound (FeZn13) that forms at the kettle bottom from iron pickup off the article surface. Skimmed manually from the kettle as a dense slurry, typically 95% Zn plus 5% Fe. Sold to zinc refiners for recovery. Skim operation generates a brief zinc fume spike captured by the kettle hood.

Zinc ash: Zinc oxide skin that forms on the molten metal surface from oxidation plus flux residue. Skimmed by hand during article exit. Typical composition 70 to 80% Zn as ZnO plus residual flux. Sold to zinc refiners or to galvanising industry secondary recovery for zinc reclamation.

Spent pickle liquor: Iron chloride or iron sulfate from the exhausted pickle bath. Drained from the pickle tank to a chemical bund, neutralised on site or shipped to specialist contractors for iron recovery or hazardous waste landfill. Spent HCl pickle liquor at 250 to 300 g/L iron is the most valuable waste stream and is increasingly recovered for resale to water treatment plants. HVAC at the spent pickle liquor handling area requires 316L stainless local extract for residual acid mist plus dedicated bund with chemical resistant lining.

3.15 Building general extract and make up air

Sitting above all the dedicated LEV branches is the building general extract and make up air system. The galvaniser building, the powder coat shop, the anodise line and the CGL must each maintain neutral or slightly negative pressure overall while specific zones (operator control cabins, laboratories, offices) are positive pressure. Building general extract at 4 to 6 ACH supplements the LEV in the kettle bay, the pickle bay and the powder cure bay. Make up air at the same volume is tempered, filtered and delivered through high level diffusers in 316L stainless or hot dip galvanised supply mains. The make up air system is the single most often neglected design issue in coatings HVAC retrofits — the operator turns up the kettle hood, the building goes negative, the kettle stack backdrafts, the operator floor floods with zinc fume, the LEV is blamed when the real issue is the make up air.

4. Material selection — why galvanised fails and what replaces it

Galvanised duct is the workhorse of HVAC fabrication. Across data centres, commercial towers, hospitals and schools, hot dip galvanised carbon steel sheet to AS/NZS 4254 is the right answer for 95% of duct work. In a galvanising plant, it is the wrong answer for almost every duct.

4.1 Galvanised carbon steel — the failure modes

Galvanised carbon steel fails in coatings exhaust for four reasons. First, chloride attack: HCl mist from the pickle line dissolves the zinc coating within weeks, exposing bare carbon steel to the corrosive humid stream. Within 6 to 8 weeks a galvanised duct downstream of an HCl pickle bath has lost its zinc coating; within 6 months the bare steel is perforated. Second, sulfate attack: sulfuric acid mist forms zinc sulfate ZnSO4 that flakes off the duct surface as hygroscopic dust, contaminating the air stream and failing the duct. Third, temperature: zinc volatilises above 419 degC and fumes above 250 degC service. The kettle hood interior, at 250 to 400 degC service, exceeds the safe operating temperature for galvanising. Fourth, condensation: condensation of acid mist on galvanised duct at any temperature accelerates the chemistry of zinc loss.

4.2 316L stainless — the workhorse for acid mist and Zn fume cool side

316L stainless steel (Cr 16 to 18%, Ni 10 to 14%, Mo 2 to 3%, C 0.03% maximum) is the workhorse material for coatings HVAC. The molybdenum content gives chloride pitting resistance equivalent number PREN above 25, enough to withstand HCl mist condensation and ZnCl2 flux fume at service temperatures up to 250 degC. 316L is used for: pickle line canopy hoods, immediate pickle line downstream main, flux dip extract, kettle hood downstream of the air cooler, post quench LEV, passivation LEV, anodise tank LEV (SAA, TSA, BSAA), electroplate LEV, and any duct in contact with cooling water. Standard gauge is 1.2 to 1.5 mm for general service, 1.5 to 2.0 mm for high concentration acid mist service.

316L pitting failure inside 24 months is common at the pickle line interface if the duct is not properly passivated after welding. The cure is post weld nitric acid passivation (20% HNO3 paste, 10 minute contact, DI rinse) to restore the chromium oxide passive layer. Welded duct without passivation fails in months; passivated duct gives 15 to 25 year service.

4.3 309S and 310S heat resistant stainless — the kettle hood

For the kettle hood underside operating at 250 to 400 degC continuous service, neither galvanised nor standard 316L will last. The material is 309S (23% Cr, 14% Ni) or 310S (25% Cr, 20% Ni) heat resistant austenitic stainless at 1.6 to 3 mm gauge, with optional refractory lining on the underside facing the bath. 309S and 310S resist oxidation, scaling and creep at 400 degC continuous and short term excursion to 1000 degC. The heavier wall section provides thermal mass plus mechanical resistance to dross splash and operator tool contact during kettle maintenance. The 309S and 310S kettle hood is the most expensive duct section in any galvanising plant by an order of magnitude per metre, but lasts 10 to 20 years with proper inspection and patch repair.

4.4 FRP fibreglass reinforced plastic — the pickle line alternative

FRP fibreglass reinforced plastic (vinyl ester resin laminate with fibreglass mat reinforcement) is the durable alternative to 316L for the long horizontal runs of pickle line extract and the wet scrubber inlet. FRP is chemically inert to HCl mist, sulfuric mist, HF, NaOH and most plating chemistries. Service temperature up to 100 degC for vinyl ester laminate, 150 degC for higher spec polyester laminate. FRP is significantly cheaper than 316L per square metre and is the practical material for the bulk of pickle line duct length above 600 mm diameter. FRP comes from specialist fabricators rather than from sheet metal lines, but the stainless to FRP transition spool (a 316L bolted flange face mated to an FRP flange face with EPDM full face gasket) is fabricated on the SBKJ machine fitment for delivery to site.

4.5 Aluminised steel — the powder cure oven workhorse

Aluminised steel (carbon steel coated with aluminium silicon alloy by hot dip process) is the material of choice for medium temperature powder cure oven exhaust between the oven and the carbon adsorber or thermal oxidiser. Service temperature 400 to 600 degC, good corrosion resistance to mildly acidic exhaust, good abrasion resistance against fine dust. Aluminised steel is cheaper than 316L and is the practical choice for cure oven exhaust mains across the Australian powder coat sector.

4.6 Heavy gauge GAL galvanised — the kettle enclosure outer skin

For enclosed kettle designs (the modern Korvest and Industrial Galvanizers approach), the outer skin of the enclosure is built in heavy gauge GAL galvanised sheet at 1.6 mm. This is counterintuitive — galvanised at a galvaniser? — but works because the outer skin never contacts the hottest fume directly, the enclosure design separates the hot zone from the structural outer skin, and the heavy gauge gives mechanical strength for crane bumping during article handling. The inner shell of the enclosure facing the bath is refractory lined heavy stainless. The combination is cheaper than full stainless construction and gives 15 to 20 year service life. SBKJ’s SBAL-III handles 1.6 mm heavy gauge GAL galvanised at 8 to 12 m of finished duct per minute, making the SBAL-III the production solution for the enclosure outer skin manufacturing.

5. Operators — mapping the Australian coatings sector

The Australian coatings sector is consolidated, capital intensive and concentrated in five operator clusters. Knowing the operators is essential for any fabricator targeting service contracts in this segment.

5.1 BlueScope Steel ASX:BSL — Port Kembla NSW

BlueScope is Australia’s biggest steelmaker by tonnage and the only operator of continuous galvanising lines at industrial scale. Port Kembla NSW is the integrated steelmaking facility with blast furnaces, basic oxygen steelmaking, hot strip mill, cold rolling and three continuous galvanising lines (CGL5, CGL6, CGL7). Western Port VIC operates the coil coating line for Colorbond pre painted steel. Product brands include Truecore structural framing steel, Colorbond, Zincalume aluminium zinc alloy, Galvalume (same chemistry, different brand) and Bondor insulated panels. From an HVAC duct perspective BlueScope is the largest single fabrication client in the country with multi year framework contracts and tight technical specifications referencing AS/NZS 4680, AS 1885 and ISO 14001.

5.2 InfraBuild — GFG Alliance Liberty Steel, Whyalla SA

InfraBuild operates the Whyalla SA electric arc furnace producing rebar, wire and rod for the construction sector. The Whyalla EAF is one of two electric arc furnace steelmaking operations in the country (the other being smaller secondary operations). InfraBuild’s HVAC envelope is steelmaking led rather than coatings led: EAF fume capture, baghouse, rolling mill scale handling. Several Australian galvanisers use InfraBuild rebar and wire as feedstock for galvanise contracts including transmission tower and rail infrastructure.

5.3 Industrial Galvanizers — Boral subsidiary, six site network

Industrial Galvanizers is the country’s biggest batch hot dip galvaniser by branch network. As a Boral subsidiary the operation runs six major sites: Hexham NSW (the flagship operation with the largest kettle in the country), Adelaide SA, Brisbane QLD, Perth WA, Melbourne VIC and Newcastle NSW. Each site runs the standard sequence of pickle, flux dip, kettle, quench and passivation with site specific variations on kettle size, hood design and waste management. The HVAC fabrication footprint at each site is substantial: kettle hoods at 309S heavy gauge, pickle line 316L plus FRP, flux dip 316L, building extract general. A national framework contract with Industrial Galvanizers across the six sites is a 10 to 15 year revenue stream for any fabricator with the SBKJ machine fitment.

5.4 Korvest ASX:KOV — Adelaide SA

Korvest is the listed Adelaide SA combined galvanising and downstream finished product manufacturer. The operation includes a major hot dip galvanise kettle, EZYStrut cable tray manufacturing, Galvalume sheet handling, pole and pipe galvanising and downstream powder coat. Korvest is a high spec, high quality operation with tight technical specifications and is the most demanding single galvaniser in the country in terms of HVAC compliance. The HVAC stack covers HDG kettle, downstream slitting line, powder coat, and EZYStrut fabrication shop extract.

5.5 Galform, Otway, Pacific, Hutchinson — regional batch operations

Galform (Trafford Group) operates batch galvanising at Brisbane and Sydney with focus on steel pipe galvanising and larger article handling. Otway Galvanizers VIC, Pacific Galvanizers and Hutchinson Galvanising Wagga Wagga round out the regional batch operations. Each operates a single major kettle with the standard pickle, flux, kettle, quench sequence. The HVAC fabrication footprint per site is smaller than the major Industrial Galvanizers branches but the total opportunity across the regional tier is significant.

5.6 Akzo Nobel Powder Coatings (formerly Interpon)

Akzo Nobel Powder Coatings is the largest powder coat formulator in the Australian market by volume, with manufacturing and stocking sites in Sydney, Melbourne, Brisbane, Perth and Adelaide. The HVAC envelope is powder manufacturing (raw material handling, milling, blending, extrusion, micronising) plus solvent extraction at the raw material handling stage. ATEX and AS/NZS 60079 compliant equipment throughout. The powder coat manufacturing duct fabrication scope is heavy gauge stainless plus conductive bonded galvanised, with major focus on dust hazard area compliance.

5.7 Dulux Powder Coatings — DuluxGroup ASX:DLX

Dulux Powder Coatings is the second major Australian powder coat formulator with sites at Penrith NSW, Granville, Eastern Creek, Yarrambat VIC, Eagle Farm QLD, Welshpool WA and Wingfield SA. The HVAC envelope mirrors Akzo Nobel: powder manufacturing dust extraction with ATEX compliance, solvent extraction at raw material handling, and ancillary cure oven exhaust at the lab and pilot production lines.

5.8 Jotun, Tiger, IGI, PPG — second tier powder formulators

Jotun Powder Coatings, Tiger Coatings, IGI Coatings and PPG Industries Australia round out the powder formulator tier. Smaller manufacturing footprints, but similar HVAC compliance requirements.

5.9 Capral Aluminium ASX:CAA — the architectural anodise leader

Capral Aluminium is the largest aluminium extrusion and anodise operation in Australia. The HVAC envelope is anodise tank line (SAA primarily, with some hard anodise capacity), powder coat applicator capacity for architectural finishes, and aluminium extrusion press exhaust. Capral works to the Aluminium International Australia AIA industry guidelines plus Capral internal technical specifications.

5.10 AWS Architectural Window Systems — architectural anodise applicator

AWS Architectural Window Systems is the major commercial anodise and powder coat applicator for the architectural aluminium window and door market. The HVAC envelope is anodise tank line plus powder coat plus pre paint cleaning. AWS serves the major builder and developer market with multi storey commercial fabrication.

5.11 Industry bodies — GAA, APCA, ASI, AIA

Galvanizers Association of Australia GAA is the industry body for hot dip galvanising and publishes the AS/NZS 4680 supporting technical guidance. Australian Powder Coaters Association APCA covers the powder coat applicator tier. Australian Steel Institute ASI covers the broader steel sector including pre paint and galvanise feed. Aluminium International Australia AIA covers the aluminium extrusion and anodise sector. Membership of the relevant industry bodies and attendance at the annual GAA and APCA conferences is essential for any fabricator targeting service contracts in this segment.

6. SBKJ machine fitment — the production envelope for the Australian coatings sector

An Australian fabricator targeting service contracts with BlueScope, Industrial Galvanizers, Korvest, Galform, Capral, AWS and the broader coatings sector needs a specific machine fitment to cover the material and gauge range from 0.7 mm galvanised for powder coat overspray duct through to 3 mm 309S heavy gauge stainless for the kettle hood. The SBKJ Product Catalog 2026 covers the full envelope with a focused six machine fitment:

6.1 SBAL-V auto duct line — the 316L stainless workhorse

The SBAL-V is the central machine for the coatings segment. It handles 304 and 316L stainless coil from 0.7 mm to 1.6 mm sheet alongside galvanised and aluminised carbon steel, with stainless specific tooling, protective film application, work hardening compensation on the brake press and TDF flange forming on stainless. The SBAL-V production rate on 1.0 mm 316L is approximately 4 to 6 m of finished duct per minute when fitted with the stainless option, 8 to 10 m/min on equivalent galvanised. The SBAL-V handles the bulk of the pickle line 316L production, the flux dip 316L production, the kettle downstream 316L production, the anodise 316L production, and the electroplate 316L production. Bedrock machine for any coatings fabricator.

6.2 SBAL-III auto duct line — the heavy gauge carbon steel workhorse

The SBAL-III handles galvanised, aluminised and painted carbon steel sheet up to 2.0 mm with TDF flange forming, Pittsburgh lock or snap lock seam forming, and full automation through coil entry, levelling, notching, shearing, brake press forming and flange roll. The SBAL-III is the production solution for: 1.6 mm heavy gauge GAL galvanised kettle enclosure outer skin, 1.6 to 2.0 mm aluminised steel powder cure oven exhaust mains, 1.6 to 2.0 mm carbon steel building extract mains in clean make up zones, and the bulk of the 1.6 mm heavy gauge work across the coatings sector. Production rate is 8 to 12 m of finished duct per minute on 1.6 mm gauge.

6.3 SBSF-1525 stitchwelder — continuous TIG bead on 316L

For chemical fume resistant duct, the lock seam must be continuously TIG welded rather than relying on sealant alone. The SBSF-1525 stitchwelder runs the longitudinal lock seam through a continuous TIG welding head at 500 to 800 mm/min travel speed in 1.5 mm 316L, using argon shield gas at 12 L/min. The weld penetrates the lock interlock and gives a hermetic continuous bond that withstands HCl mist condensation pitting, chloride stress corrosion cracking and sulfuric acid attack. The SBSF-1525 is essential for: pickle line 316L mains, flux dip 316L extract, kettle downstream 316L cooling section, and CGL annealing furnace heavy 309S/310S stainless exhaust mains. The SBSF-1525 is also the right machine for heavy gauge 200 to 450 degC kettle exhaust 309S/310S stainless because the continuous TIG bead gives the necessary high temperature integrity.

6.4 SB-ZF1500 longitudinal stitch welder — the spiral chemical service bond

For trunk mains above 1000 mm diameter where the spiral seam needs continuous longitudinal stitching alongside the spiral lock, the SB-ZF1500 longitudinal stitch welder operates in line with the SBFB-1500 to deposit a continuous TIG bead along the formed spiral. This double bond (spiral mechanical lock plus continuous TIG longitudinal weld) is the standard construction for HCl pickle line mains, sulfuric acid mist mains, kettle building extract mains and CGL annealing furnace exhaust. Critical for any fabricator targeting BlueScope CGL contracts at 1500 to 2000 mm diameter spiral.

6.5 SBFB-1500 spiral tubeformer — the powder coat and spiral workhorse

The SBFB-1500 spiral tubeformer is the production solution for 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. For powder coat overspray collection at 15 to 18 m/s transport velocity the SBFB-1500 produces 0.9 to 1.2 mm galvanised spiral with continuous lock seam, fully conductive between sections via flange bonding straps for AS/NZS 60079.10.2 Zone 22 dust hazard compliance. For pickle line spiral the SBFB-1500 produces 1.0 to 1.5 mm 316L spiral with TIG welded seam. The SBFB-1500 is the spiral powder coat conveying workhorse for fabricators serving the Akzo Nobel and Dulux applicator network.

6.6 SBPC1500 plasma cutter — the heavy gauge custom geometry tool

The SBPC1500 plasma cutter handles 316L stainless and carbon steel up to 25 mm thickness with HD plasma cut quality: clean kerf, minimal HAZ, no slag adhesion. The SBPC1500 cuts: kettle hood transitions and refractory anchor stud plates, pickle bath canopy hood mitres, flux dip dryer transitions, post dip cooling tower transitions, powder cure oven plenum ends and expansion joint flanges. Production rate is approximately 1.5 m/min on 1.5 mm 316L sheet. For the heavy gauge 200 to 450 degC kettle exhaust the SBPC1500 cuts the heavy 309S and 310S transitions where manual plasma or oxy fuel would bottleneck.

6.7 SBLR-600 lock former — the seam forming tool

The SBLR-600 lock former forms the Pittsburgh lock or snap lock longitudinal seam profile on rectangular duct sections. For 1.5 mm 316L stainless use the heavy gauge tooling set and reduce forming speed by 30% compared to galvanised. The SBLR-600 handles up to 1.6 mm gauge in galvanised, 1.5 mm in 316L stainless.

6.8 SBTF-1500/1602/2020 spiral — the run out tables and large diameter

The SBTF series spiral formers cover the larger diameter range: SBTF-1500 to 1500 mm, SBTF-1602 to 1600 mm, SBTF-2020 to 2000 mm. For CGL trunk mains and large diameter kettle building extract the SBTF-2020 is the production solution. The SBTF series doubles as run out table for finished spiral duct lengths up to 12 m before transport.

6.9 The 25 to 50 m kettle hood ductwork case

A typical major kettle installation requires a continuous 25 to 50 m of kettle hood ductwork running from the kettle face to the air cooler to the baghouse inlet. The construction is heavy gauge stainless (309S or 310S at 1.6 to 3 mm for the hot section, transitioning to 316L at 1.5 to 2.0 mm downstream of the cooler) with continuous TIG welded longitudinal seam and bellows expansion joints at every 12 to 15 m for thermal growth. The SBKJ machine fitment for this scope is the SBAL-V plus SBSF-1525 in tandem for the 316L cool section, plus manual fabrication with SBSF-1525 stitch welding for the heavy 309S/310S hot section, plus SBPC1500 plasma cutting for the custom transitions, plus SBAL-III for the heavy gauge enclosure outer skin where required. The complete fitment delivers a 25 to 50 m kettle hood project in 4 to 6 weeks for a single fabricator team, versus 10 to 14 weeks for a fabricator without the SBSF-1525 continuous TIG capability.

7. Construction sequence — how a coatings duct project executes from spec to commissioning

A coatings HVAC duct project from contract award through to commissioning runs on a predictable sequence with characteristic risk points. Knowing the sequence allows the fabricator to programme correctly and to price the work realistically.

7.1 Specification and design freeze (weeks 0 to 4)

The project starts with the client’s engineering team or external consultant freezing the specification. For a major Industrial Galvanizers or BlueScope project the spec references AS 1668.2, AS 4254, AS/NZS 4680, AS 1885 and the relevant SafeWork Australia exposure standards, with site specific addenda for material gauge, flange type, hanger spacing and corrosion protection. The fabricator’s role at this stage is to review the spec for buildability, suggest cost optimisations (where 316L can be substituted for 309S without compromising service life, where FRP can replace 316L for long horizontal runs), and confirm the bill of quantities.

7.2 Material procurement and lead time (weeks 2 to 8)

316L stainless coil at 1.5 to 2.0 mm gauge is on 6 to 10 week lead time from Australian steel service centres. 309S and 310S heavy gauge stainless at 1.6 to 3 mm is on 10 to 16 week lead time and often requires import order from European or East Asian mills. Aluminised steel is on 8 to 12 week lead time. Galvanised coil is on 2 to 4 week lead time from BlueScope. Material procurement is the single biggest schedule risk on a coatings project — the fabricator with an established coil stocking position is significantly more competitive than the spot buyer.

7.3 Fabrication (weeks 4 to 14)

With material in stock the fabrication runs on the SBKJ machine fitment described above. Typical fabrication throughput for a 25 to 50 m kettle hood scope is 4 to 6 weeks for a single team running two shifts. Pickle line 316L scope at 30 to 50 m of mains plus canopy hoods is 6 to 8 weeks. Powder coat booth duct scope at 100 to 200 m of mains and branches is 4 to 6 weeks. CGL fabrication scope is significantly larger and runs 12 to 24 weeks depending on the section of the line.

7.4 Pressure test, passivation and packaging (weeks 12 to 16)

Each duct section is pressure tested at 1.5x design pressure for 30 minutes with chalk and water test fluid on the lock seam to detect any pinhole leak. 316L weld zones are passivated with 20% nitric acid paste, 10 minute contact, DI rinse, to restore the chromium oxide passive layer. Packaging with PE protective film intact for site delivery.

7.5 Site delivery and installation (weeks 14 to 20)

Site delivery from Box Hill North VIC by road freight: 1 day to Otway Galvanizers VIC and Korvest Adelaide SA, 2 days to Industrial Galvanizers Hexham NSW and Korvest Adelaide SA, 3 to 4 days to Industrial Galvanizers Brisbane and Perth, 4 to 5 days to BlueScope Port Kembla NSW. Installation by the client’s mechanical contractor under HVAC commissioning sequence: hangers installed first, duct sections lifted into position, flanges bolted with EPDM full face gaskets for chemical service or fibre gaskets for general service, bellows expansion joints installed at marked locations, instrumentation tappings sealed.

7.6 Commissioning and air balance (weeks 18 to 22)

Commissioning under AS/NZS 4030 air balance procedure: fan testing, baghouse and scrubber commissioning, capture velocity measurement at each hood face, transport velocity measurement at each branch, breathing zone air sampling to verify SafeWork Australia exposure compliance, and final compliance certificate to AS/NZS 4680, AS 1668.2 and AS 1885. Final commissioning takes 2 to 4 weeks depending on the scope.

7.7 Warranty and after sales service

Coatings HVAC duct work carries a 24 to 60 month warranty depending on the material specification and service. Standard galvanised duct warranty is 24 months; 316L stainless duct warranty is 60 months including passivation defect coverage; FRP fibreglass duct warranty is 36 to 60 months from the FRP fabricator. After sales service includes annual inspection of the heavy 309S kettle hood for refractory backing condition and stainless surface oxidation, biennial inspection of the pickle line 316L for chloride pitting, and 5 yearly NDT inspection of the FRP fibreglass for laminate condition.

8. The ARBS 2026 Sydney positioning — targeting the coatings segment

ARBS 2026 in May 2026 at the Sydney International Convention Centre is the major Australian HVAC trade show. For SBKJ Group attending ARBS 2026 the coatings segment is one of the highest value market entry opportunities. The Australian coatings sector is consolidated, technically sophisticated and price disciplined, with multi year framework contracts being awarded across the major operators (BlueScope, Industrial Galvanizers, Korvest, Galform, Akzo Nobel, Dulux, Capral, AWS) on a continuous rolling basis. An Australian fabricator targeting this segment can lock in 10 to 20 year service contract revenue with the right machine fitment plus the right material selection knowledge plus the right standards understanding.

The pitch at ARBS 2026 is built around three propositions. First, the SBKJ machine fitment (SBAL-V plus SBAL-III plus SBSF-1525 plus SB-ZF1500 plus SBFB-1500 plus SBPC1500 plus SBLR-600 plus SBTF series) covers the full coatings material and gauge envelope from 0.7 mm galvanised for powder coat duct through to 3 mm 309S/310S for kettle hood — an end to end fitment that no single competitor matches at the same capital cost. Second, the engineering knowledge base covers AS/NZS 4680 hot dip galvanising, AS 1668.2 building extract, AS 4254 duct construction, AS/NZS 60079 hazardous area, AS 3957 dust hazard, NFPA 484 combustible metals, NFPA 660 consolidated dust and NFPA 86 industrial furnace, plus the relevant SafeWork Australia exposure standards. Third, the production envelope delivers a 25 to 50 m kettle hood project in 4 to 6 weeks for a fabricator running the full SBKJ fitment versus 10 to 14 weeks for a fabricator without the SBSF-1525 continuous TIG capability — a competitive differentiator that locks in the framework contracts.

The ARBS 2026 booth focus for SBKJ Group is the SBAL-V live demonstration on 316L stainless for pickle line acid mist duct, the SBFB-1500 live demonstration on powder coat overspray spiral, and the SBSF-1525 continuous TIG bead demonstration for chemical service. Site visits to Industrial Galvanizers Hexham NSW, Korvest Adelaide SA, BlueScope Port Kembla NSW and Capral Aluminium can be programmed in the week before or after ARBS 2026 to convert show enquiries into specification work.

9. Common engineering errors and how to avoid them

Three recurring engineering errors show up in coatings HVAC retrofits and new build projects across the Australian sector. Each is avoidable with the right material selection, the right capture velocity and the right machine fitment.

9.1 Substituting galvanised for 316L on pickle line cool side

The most common error. The fabricator price compares a 316L pickle line scope to a galvanised alternative, the operator is tempted by the 30 to 40% price reduction, and the duct goes in. Within 6 to 8 weeks the zinc coating is gone, within 6 months the bare steel is perforated, within 12 months the duct is being replaced under warranty or under emergency repair. The correct approach is 316L stainless minimum 1.2 mm gauge for the pickle line cool side downstream of the canopy hood, with FRP fibreglass as the only acceptable cheaper alternative for the long horizontal runs.

9.2 Undersizing the kettle hood extract under building negative pressure

The second most common error. The fabricator sizes the kettle hood extract to the AS/NZS 4680 minimum 80 ACH but neglects the building general extract and make up air. The operator runs the kettle, the building goes negative, the kettle stack backdrafts, the operator floor floods with zinc fume. The correct approach is to size the kettle hood extract at 80 to 100 ACH PLUS the building general extract at 4 to 6 ACH PLUS matched make up air at 100% of total exhaust through tempered, filtered diffusers in the kettle bay.

9.3 Neglecting conductive bonding on powder coat spiral

The third most common error. The fabricator runs galvanised spiral powder coat duct without conductive bonding between sections. Static charge accumulates on the spiral interior, the minimum ignition energy of polyester powder (10 to 30 mJ) is exceeded, and the duct ignites internally. The correct approach is conductive bonding straps across every flange, all metalwork bonded to building earth, and powder collection equipment bonded and grounded per AS/NZS 60079.10.2 plus AS 3957 plus NFPA 660. The SBFB-1500 spiral tubeformer includes flange bonding strap fitment as standard for the powder coat market.

10. The Cr VI phase out — what changes for the HVAC fabricator

The Cr VI phase out across the Australian coatings sector is the single biggest chemistry shift of the decade and has direct implications for HVAC duct fabrication. SafeWork Australia tightened the Cr VI workplace exposure standard to 0.05 mg/m3 in 2024, with proposals under active review to tighten further. IARC classifies Cr VI as Group 1 human carcinogen. The phase out is being driven by SafeWork pressure, customer specification pressure and chemistry availability.

Three chemistry replacements are now in service. Trivalent chromium Cr III replaces chromate conversion coating on galvanised steel. Tartaric sulfuric anodise TSA and boric sulfuric anodise BSAA replace chromic acid anodise CAA for aerospace and defence aluminium. Nickel acetate and hot water sealing replace chromate sealing on architectural anodise. Each replacement chemistry has its own HVAC envelope but each is significantly less aggressive than the Cr VI predecessor.

For the HVAC fabricator the Cr VI phase out reduces the volume of duct dedicated to Cr VI service by 60 to 80% across a typical anodise line refurbishment. The remaining Cr VI duct (chrome plate, legacy chromate sealing) still requires 316L stainless dedicated LEV with HEPA polish and stack monitoring. The new Cr III, TSA, BSAA and SAA non chromate duct needs only standard 316L without the HEPA polish. The capital cost of a non chromate anodise line LEV is 30 to 50% lower than a chromate line LEV, and the OPEX is 20 to 40% lower due to reduced HEPA filter replacement and reduced stack monitoring frequency.

11. Galvanneal, Zincalume and Galvalume — the alloy variants

Three alloy variants of zinc coating sit alongside standard hot dip galvanise and standard CGL galvanise:

Galvanneal: Hot dip galvanise followed by in line annealing at 500 to 565 degC to convert the pure zinc coating to a zinc iron intermetallic (Zn Fe alloy at the surface, 8 to 12% Fe). The Galvanneal coating is matte rather than spangled, paintable without phosphate pre treatment, and used extensively in automotive body panels. The HVAC implication is an additional annealing furnace exhaust at 500 degC service requiring 309S stainless heavy gauge plus NFPA 86 burner management. Galvanneal is produced on dedicated CGL lines; in Australia the production is limited to specific CGL runs at Port Kembla.

Zincalume: Aluminium zinc alloy coating (55% Al, 43% Zn, 1.5% Si). BlueScope’s registered brand. Produced on CGL5/CGL6/CGL7 at 470 degC pot temperature. Higher corrosion resistance than standard galvanise, particularly under marine and tropical climate. The HVAC envelope is identical chemistry to CGL galvanise but at slightly higher pot temperature.

Galvalume: Same chemistry as Zincalume (55% Al, 43% Zn, 1.5% Si) under a different brand and licence agreement. Produced on the same CGL lines. HVAC identical to Zincalume.

12. Pre paint metal finishing — the Colorbond paint coating envelope

The Colorbond paint coating line at BlueScope Western Port VIC handles the pre paint and final paint application to galvanised and Zincalume strip. The line runs: pre paint clean (alkaline degrease, rinse, conversion coat), prime coat application (epoxy primer roll coat), prime coat oven cure at 230 degC, top coat application (polyester or polyurethane), top coat oven cure at 230 to 245 degC. The HVAC envelope adds solvent VOC extraction at the wet coating section (paint application roll coat) and high temperature exhaust at the cure ovens. Total VOC emission per shift is significant; the line operates with regenerative thermal oxidiser RTO destruction of solvent VOC to CO2 plus water before stack discharge under state EPA licence. Duct construction is aluminised steel at the cure oven section, 316L stainless at the solvent extraction section, and standard galvanised at the cool side.

13. The fabricator’s commercial case — ROI on the SBKJ coatings fitment

The commercial case for the SBKJ coatings fitment is the framework contract revenue stream from the major Australian operators. A national framework contract with Industrial Galvanizers across the six sites covers 5 to 10 years at $2 to 5M annual fabrication revenue. A framework contract with BlueScope for CGL maintenance and refurbishment covers 10 to 20 years at $3 to 8M annual revenue. A framework contract with Korvest covers 5 to 10 years at $1 to 3M annual revenue. A framework contract with the major powder coat applicators covers 5 to 10 years at $500K to 2M per major site. Total addressable market for an Australian fabricator with the full SBKJ coatings fitment is $10 to 25M annual revenue locked in over 10 to 20 year contracts. Capital cost of the full fitment is $1.2 to 2.0M depending on selected machine options.

Payback period is 12 to 24 months on the framework revenue, with 20 year service life on each machine giving 8 to 10x return on capital across the fitment life. The economic case is the highest single sector ROI of any Australian HVAC fabricator investment, on the strength of the consolidated buyer base, the multi year framework contract structure, and the technical barrier to entry created by the AS/NZS 4680 compliance plus material selection knowledge.

14. Conclusion — specifying coatings HVAC and the SBKJ machine fitment

Hot dip galvanising, pickling, continuous galvanising line, powder coating, anodise aluminium and zinc coating plant HVAC is a specialist engineering discipline. The chemistry is aggressive, the temperature is high, the dust hazard is real, and the regulatory stack is comprehensive. AS/NZS 4680 hot dip galvanising plus AS 1668.2 building extract plus AS 4254 duct construction plus AS/NZS 60079 hazardous area plus AS 3957 dust hazard plus NFPA 484 combustible metals plus NFPA 660 consolidated dust plus NFPA 86 industrial furnace plus the SafeWork Australia exposure standards for ZnO fume, HCl mist, sulfuric mist, HF, Cr VI, isocyanate, formaldehyde and the rest of the chemistry envelope — the standards stack is comprehensive and the engineering team must work across all of them.

The Australian sector is large, consolidated and durable. BlueScope, InfraBuild, Industrial Galvanizers, Korvest, Galform, Otway, Pacific, Hutchinson on the galvanising side. Akzo Nobel, Dulux, Jotun, Tiger, IGI, PPG on the powder coat formulator side. Capral and AWS on the anodise side. The framework contract revenue is locked in over 10 to 20 year cycles. The fabricator with the right machine fitment plus the right material selection knowledge plus the right standards understanding can build a service business on this segment with multi million dollar annual revenue and 8 to 10x return on capital across the machine life.

The SBKJ Product Catalog 2026 machine fitment for the Australian coatings segment is SBAL-V plus SBAL-III plus SBSF-1525 plus SB-ZF1500 plus SBFB-1500 plus SBPC1500 plus SBLR-600 plus SBTF-1500/1602/2020. Together the fitment covers the full material and gauge envelope from 0.7 mm galvanised for powder coat overspray duct through to 3 mm 309S/310S heavy gauge stainless for kettle hood, with continuous TIG welded longitudinal seam capability across the full 316L stainless range. Twelve to twenty four month payback on framework contract revenue, eight to ten year service life on the fitment, and a defensible competitive position in the most technically demanding HVAC fabrication segment in Australian heavy industry.

15. Contact SBKJ Group — talk to the engineering team

SBKJ Group designs and supplies HVAC duct fabrication machinery to fabricators serving the Australian coatings, galvanising, pickling, powder coat and anodise sector. The engineering team at Box Hill North VIC supports specification, machine selection, fitment design, commissioning and after sales service across the country. For framework contract opportunity, machine demonstration, ARBS 2026 booth visit or site engineering visit at Industrial Galvanizers, Korvest, BlueScope Port Kembla, Galform, Capral Aluminium or any other Australian coatings operator, contact the team directly.

SBKJ Group
Email: sales@sbkjduct.com
Phone: +61 435 074 994
Web: sbkjduct.com
Address: Box Hill North, Melbourne VIC 3129, Australia
ARBS 2026 attendance confirmed: May 2026, Sydney International Convention Centre