Why renewable manufacturing is now an Australian HVAC ductwork story
For two decades, Australia's role in the renewable energy supply chain was that of an exporter of raw inputs and an importer of finished kit. Wind turbine blades, nacelles, solar panels, battery cells and electrolyser stacks arrived from offshore manufacturers, were unloaded at port, trucked to site, bolted together and connected to a grid that until recently was still designed around coal-fired baseload. The factories that built the equipment were somewhere else.
That model has now broken structurally. The Future Made in Australia programme — announced in the 2024 federal budget at AUD 22.7 billion (USD 22.7 billion) — has put national-treasury weight behind onshore renewable manufacturing capacity. State governments have stood up dedicated renewable manufacturing precincts: the Hunter region for offshore wind component fabrication, Gladstone for hydrogen and ammonia export, Geelong for battery components, Geraldton for vanadium flow battery, and Sydney for solar mounting and PV cell R&D. The pipeline of offshore wind projects in Bass Strait, the Illawarra, Hunter, Portland and the Southern Ocean has finally generated enough domestic demand to make blade, nacelle and tower fabrication commercially studyable on Australian soil.
For HVAC ductwork engineers, this is a new category of project. Renewable manufacturing plants are not comfort HVAC jobs — they are industrial process ventilation jobs with hazardous-area classifications, combustible-dust hazards, solvent and resin vapour capture, paint-shop downdraft, lamination cure ovens and clean-ambient nacelle bays. AS 1668.2, AS/NZS 60079, NFPA 33, NFPA 484, IEC 61400 and ASTM D3878 each control a different layer. Getting any one of them wrong is not a comfort issue — it is a permit issue, an insurance issue and in the worst case a deflagration risk that can write off the facility.
This guide is the reference SBKJ engineers use when customers — fabricators, EPCs, OEM service partners and the new generation of Australian renewable manufacturers — ask what duct material, construction class, fan and filtration package and SBKJ machine configuration is right for their plant.
The standards stack — what governs the design
A renewable manufacturing plant in Australia is governed by a stack of overlapping standards, each layered on top of the more general ones. The HVAC designer who tries to work from a single document — most often AS/NZS 4254 alone — will end up with a non-compliant design every time. Six standards do most of the work.
AS 1668.2 — industrial ventilation
AS 1668.2 is the Australian standard for the use of mechanical ventilation in buildings, with Part 2 specifically addressing the ventilation of contaminated air. For renewable manufacturing it is the starting point: it sets the industrial ventilation rate per process zone, defines the makeup air requirement, and prescribes minimum stack discharge heights for solvent, resin and combustion exhaust. Every process room in a blade plant, paint shop, nacelle bay, lamination line and electrolyser fabrication hall has to pass an AS 1668.2 calculation before any other standard layers in. The number that comes out of AS 1668.2 — usually in litres per second per square metre of contaminated source, or in air changes per hour for an enclosed room — is the floor below which no design can go.
AS/NZS 60079 — hazardous-area classification
The AS/NZS 60079 series adopts the IEC 60079 framework for the classification of areas in which an explosive gas or dust atmosphere may be present, and the selection of equipment certified for use in those zones. Wind turbine blade plants contain Zone 1 and Zone 2 gas atmospheres around resin and solvent stores and during open-vat layup operations. Carbon fibre and glass fibre dust collection systems are Zone 21 or Zone 22 dust atmospheres. Hydrogen electrolyser fabrication and test bays are Zone 1 hydrogen atmospheres around process leakage points. All ventilation equipment installed in or discharging from these zones — fans, motors, instrumentation, isolation dampers — must be ATEX-certified or IECEx-certified for the specific zone, gas group (IIA / IIB / IIC) and temperature class (typically T3 or T4 for hydrocarbons, T1 for hydrogen). Plain industrial-grade kit voids the building permit and the insurance.
NFPA 33 — spray application using flammable or combustible materials
NFPA 33 is the US National Fire Protection Association standard for spray application using flammable or combustible materials. Although Australian regulators rely primarily on AS 4114 and the local equivalents, NFPA 33 is the operational reference used by paint-booth manufacturers and most Australian paint-shop designers — particularly for the polyurethane topcoats applied to wind turbine blades and the offshore-rated coatings used on towers and nacelle housings. NFPA 33 governs booth construction, air balance, dry-filter or water-curtain selection, vapour-tight construction, fan location, ducting separation distances and stack discharge geometry. A blade-plant paint shop that does not pass an NFPA 33 review will not pass an underwriter's site survey either.
NFPA 484 — combustible metals and combustible particulate solids
NFPA 484 covers combustible metals and combustible particulate solids, and it is the controlling standard for carbon fibre and glass fibre dust collection systems on the blade line. The Dust Hazard Analysis required under NFPA 484 dictates the configuration of every dust extraction header: continuous bonded conductive duct, no internal pockets or dead legs, explosion isolation devices upstream of the baghouse, explosion-vented baghouse construction, and outdoor relocation of the dust collector with the right separation distance from occupied buildings. Carbon fibre dust is a particularly aggressive case because it is both combustible and electrically conductive — a single explosion event in a non-compliant collector can write off the dust collection system, the upstream ductwork and a section of the blade hall behind it.
IEC 61400 — wind turbine generator systems
IEC 61400 is the international family of standards for wind turbine generator systems. The HVAC designer does not work directly from IEC 61400 in the way that they work from AS 1668.2, but the OEM's manufacturing specification — the document the blade plant has to satisfy to ship product to the OEM — references it constantly. IEC 61400-5 covers blade requirements, IEC 61400-23 covers full-scale blade structural testing, and IEC 61400-24 covers lightning protection. The HVAC implications come through cleanliness specifications, controlled-temperature cure windows, humidity envelopes for layup, and conductivity requirements for any equipment grounded into the lightning protection bus on the test rig.
ASTM D3878 — composite material terminology
ASTM D3878 is the standard terminology for composite materials, and although it is not a design standard in its own right, it is the dictionary every blade specification is written in. When an OEM specification calls out a "Type I fibre-dominated lamina" or a "B-stage prepreg" or a "post-cure cycle to vitrify the resin", the HVAC designer who does not recognise the terminology will mis-size the cure-oven exhaust or the layup-room dehumidification. SBKJ engineers treat ASTM D3878 as required reading before any blade-plant HVAC scope.
The wind turbine — what gets manufactured and where the HVAC load is
A utility-scale wind turbine in 2026 — whether onshore at 5–7 MW or offshore at 12–18 MW — is built in three principal subassemblies: blades, nacelle and tower. Each is manufactured in a different plant, with a different HVAC load profile, a different hazardous-area classification, and a different duct material specification. The same SBKJ machine line will produce duct for all three, but the duct itself looks completely different in each plant.
Blade plant — composite layup, infusion, cure, sandblast, paint
The blade plant is by a wide margin the most demanding HVAC environment in the wind turbine value chain. Modern blades are 75–120 metres long, manufactured as one-piece monocoque shells using carbon fibre and glass fibre reinforcement in an epoxy resin matrix, with a structural spar cap that may be either pultruded carbon plate or in-mould infused carbon laminate. The HVAC scope inside a single blade plant typically breaks into eight discrete process zones.
Composite layup hall — the largest single HVAC volume in the plant. Glass fibre and carbon fibre dry fabric is laid into the half-shell moulds at controlled temperature (typically 22–25 °C) and humidity (typically 35–55 % RH). The hall must achieve uniform conditions across a 100-metre mould length, with no localised draught that could disturb dry fabric placement. AS 1668.2 sets the base ventilation rate; the OEM specification often layers a tighter cleanliness target on top. Duct material in the layup hall itself can be galvanised because the contaminants are dry fibre dust at low concentration — the aggressive zones are downstream.
Resin mixing and dispensing — a Zone 1 hazardous area under AS/NZS 60079. Two-part epoxy resin systems are mixed with a hardener, sometimes with the addition of an accelerator (MEKP for some toughened systems) and pigment. The vapour load is dominated by styrene, residual monomer and solvent traces. Local exhaust ventilation captures vapour at every open-vat operation; the captured air goes through a VOC scrubber — typically a packed-bed scrubber on water with a recirculating caustic loop for the most aggressive resin systems, or a regenerative thermal oxidiser (RTO) where the VOC load is steady enough to justify the capital. Duct material in this zone is 316L stainless steel; galvanised duct fails because the zinc reacts with the MEKP catalyst and with the solvent vapour, releasing zinc soap residues that contaminate the resin and over time perforate the duct at the longitudinal seam.
Blade infusion — once the dry fabric is laid up, the mould is sealed under a vacuum bag and the resin is drawn into the laminate by vacuum-assisted resin transfer moulding (VARTM) or resin transfer moulding (RTM). During the infusion phase, residual styrene and monomer evolves from the resin into the headspace and is captured by local exhaust on the bag perimeter. The hazardous-area classification reduces to Zone 2 because the resin is contained in the bag, but the duct material must remain 316L because solvent condensation is unavoidable on cool surfaces during pump-down. Continuous welded longitudinal-seam duct is preferred over standard spiral or rectangular Pittsburgh seam because resin-laden condensate finds every gap.
Autoclave cure or oven cure — the laminated blade is cured at elevated temperature (60–90 °C) under controlled ramp and dwell profile. The cure oven exhaust is hot, humid and carries the last fraction of unreacted styrene. Duct material is 316L stainless for the first 6–10 metres downstream of the cure oven, transitioning to galvanised or painted carbon steel further downstream once the exhaust has cooled below condensation point. Insulation is mineral wool with stainless cladding to protect personnel from burn risk.
Sandblast and surface preparation — once cured, the blade is moved into a sandblast bay for surface preparation prior to paint. The sandblast bay generates a high mass flow of abrasive media (typically alumina or steel grit) plus fine particulate from the blade surface. Local exhaust is via a baghouse with media reclamation; duct material is wear-resistant — typically heavy-gauge carbon steel with replaceable wear liners at every elbow. This is one of the few zones in a blade plant where galvanised duct is acceptable because the contaminant chemistry is benign and the wear regime is the controlling factor.
Paint shop — the blade enters a downdraft paint booth for the topcoat, typically a two-pack polyurethane or a fluoropolymer offshore-grade coating. NFPA 33 governs the booth design: downdraft air balance with floor-to-ceiling air movement, water curtain or dry filter on the floor return, vapour-tight booth construction, fan located outside the booth envelope, stack discharge at the minimum NFPA 33 distance above the roof and away from any building intake. Duct material is 316L stainless throughout the booth envelope and the supply ductwork serving the booth. Booth makeup air is conditioned with humidity control to maintain the coating specification — too dry and the topcoat orange-peels, too humid and it blushes.
Carbon fibre trim and finishing — once the blade is painted and cured, it goes to trim and finishing where the root flange is machined, the lightning conductor is bonded, and any final surface defects are dressed. The carbon fibre dust generated at machining stations is the most aggressive dust hazard in the plant. NFPA 484 requires a Dust Hazard Analysis (DHA) and the resulting duct system is conductive throughout, bonded to ground continuity along its full length, with explosion isolation devices upstream of the baghouse and an explosion-vented baghouse located outside the building envelope. SBKJ supplies the carbon-black-loaded conductive duct or all-steel-mesh conductive duct option for this scope.
Comfort HVAC — the office, training, canteen and PPE areas of the blade plant are comfort HVAC and can be specified per AS/NZS 4254 in galvanised duct. We mention it because it is the largest single duct quantity in the plant by area, even though it carries the lowest engineering risk.
Nacelle assembly — clean ambient with generator and gearbox handling
The nacelle is the housing on top of the tower that contains the gearbox (or, on direct-drive designs, the direct-drive generator), the main shaft, the yaw drive, the pitch system, the converter cabinets and the control electronics. Nacelle assembly is a clean-ambient operation rather than a process operation — the loads are generator-bearing preservation, gearbox oil cleanliness, electronics dust control and welder fume capture at any structural welding stations. AS 1668.2 sets the base air change rate; the OEM specification typically calls for a target of NC-40 acoustic comfort and 22–25 °C with humidity below 60 % RH year-round. Duct material is galvanised AS/NZS 4254 Class B in most of the building, transitioning to stainless only at any wash-down zone or welding extract hood. The nacelle bay is the easiest HVAC environment in the wind turbine plant.
Tower fabrication — steel rolling and longitudinal welded seam
The tower is built as a series of conical or cylindrical steel sections, each rolled from heavy plate (typically 30–80 mm thickness) and joined by a longitudinal welded seam. Sections are then circumferentially welded into sub-modules, internally fitted out with cable trays, ladders, platforms and lighting, and finally externally coated with the offshore-rated coating system. HVAC inside a tower plant is dominated by welding fume capture, abrasive blast extract, paint booth extract and comfort HVAC for the operator stations. Duct material is mixed — 316L in the paint shop and any wash-down zone, heavy-gauge carbon steel with wear liners in the blast hall, and galvanised in the rest. Tower plants have the most predictable HVAC scope of the three because the processes are well understood from heavy-fabrication practice in shipbuilding, pressure vessel and offshore module fabrication.
Solar panel manufacturing — what is actually built in Australia
The solar manufacturing value chain has four stages: polysilicon refining, ingot and wafer production, PV cell manufacturing, and module assembly. Australian capacity is concentrated at the module assembly end of the chain — the upstream cell, wafer and polysilicon stages are dominated by overseas manufacturers and are unlikely to relocate to Australia at material scale in this decade. The HVAC scope therefore concentrates on module assembly, with a small but growing R&D segment in PV cell pilot lines.
PV cell manufacturing — pilot scale only
SunDrive Solar, based in Sydney, operates a copper-metallisation PV cell R&D and pilot manufacturing line that has demonstrated some of the highest commercial silicon cell efficiencies in the world. The HVAC scope for a cell line — even at pilot scale — is more demanding than a module line because cell processing involves wet chemistry (texturing, anti-reflection coating), high-temperature diffusion furnaces, plasma-enhanced chemical vapour deposition (PECVD) for surface passivation, and laser scribing. Each of these process steps has a specific exhaust requirement: acid fume scrubbers on the wet bench, hot exhaust ducting on the diffusion furnace, fluorine-compatible PVDF or stainless duct on the PECVD exhaust, and HEPA-filtered cleanroom supply on the scribing room. Duct material is 316L stainless throughout the wet bench and PECVD lines, with PVDF lining or full-PVDF duct on any acid-fluoride exhaust path. Cleanroom supply is typically galvanised with internal cleanroom-grade duct sealant.
Module assembly — lamination, EVA cure, frame, junction box
Module assembly is the dominant Australian capability. The line takes incoming PV cells, strings them, lays them between sheets of EVA (ethylene vinyl acetate) or POE (polyolefin elastomer) encapsulant, sandwiches them between a glass front and a backsheet (or a glass back for bifacial modules), and laminates the stack under heat and vacuum in a flatbed laminator. The cured module is then framed in aluminium extrusion, a junction box is bonded and wired, the module is electrically tested, and the finished module is packed for shipment.
The HVAC load on a module line is dominated by lamination extract. The laminator releases hot, humid air with traces of EVA decomposition products (acetic acid in particular, plus other volatiles) at every cycle vent. Acetic acid is corrosive to carbon steel and aggressively corrosive to galvanised steel. Duct material on the laminator extract is 316L stainless from the laminator hood through to the discharge stack, with continuous welded longitudinal seams to prevent acetic acid condensate from finding the seam. Downstream of the laminator, the encapsulant trimming station generates EVA dust and shred — local exhaust to a baghouse with conductive duct is appropriate. The framing line generates aluminium swarf — captured by a conventional dust collector with galvanised duct, which is acceptable because aluminium swarf is not combustible at the particle size and concentration generated. The electrical test booth is comfort HVAC. The junction box bonding station uses silicone sealant which is benign in normal operation but generates acetic acid during cure — a small dedicated local exhaust on stainless duct is standard.
Thin film — cadmium telluride and CIGS
Thin-film PV technologies — cadmium telluride (CdTe) and copper indium gallium selenide (CIGS) — are manufactured by deposition processes rather than by silicon wafer handling. Australian thin-film capacity is at the R&D scale only, but the HVAC requirements are worth noting because some emerging technology offshoots may scale up over the decade. CdTe deposition uses cadmium-containing precursors which are toxic and tightly regulated — exhaust paths require dedicated scrubbing, sealed-room construction, and full personnel decontamination protocols. CIGS deposition uses selenium-containing precursors with similar handling requirements. Duct material on a thin-film exhaust line is 316L stainless throughout, with welded seams and full pressure testing before commissioning. Thin-film plants are the most demanding HVAC environment in the solar value chain.
Australian renewable manufacturers — who is building what
This is the operator landscape an SBKJ engineer walks through when scoping a renewable manufacturing HVAC project in Australia. We include both Australian-owned manufacturers and international OEMs with Australian service-centre or manufacturing-planning presence. The list is not exhaustive — new entrants appear regularly as Future Made in Australia funding flows — but it captures the operators who are the most likely fabrication or HVAC customer prospects in 2026.
Solar
5B Generators — Sydney-based manufacturer of the Maverick prefabricated solar mounting system. 5B builds factory-assembled, foldable PV arrays that are transported flat-packed and unfolded on site, dramatically reducing installation labour for utility-scale arrays. The HVAC scope at a 5B plant is closer to a metal fabrication line than a PV manufacturing line — the company is mostly assembling and welding mounting structures rather than processing PV cells — but the trend is toward higher in-factory module integration, which would shift the HVAC scope toward module assembly extract.
SunDrive Solar — Sydney-based PV cell R&D and pilot manufacturing operation using copper rather than silver for cell metallisation. SunDrive holds multiple world-record cell efficiency results and is scaling toward commercial production. Cell-line HVAC scope as described above — 316L stainless on the wet bench and PECVD exhaust, full hazardous-area classification on the silane line, cleanroom supply on the laser and metallisation stations.
Bridie Wave and SwitchedOn Solar — boutique Australian module assembly operations producing customised modules for niche markets including building-integrated PV, marine and remote-area installations. Lamination extract is the dominant HVAC scope.
Wind — international OEM service centres in Australia
None of the global wind OEMs currently operates a full blade or nacelle manufacturing plant in Australia, but all of the major players run service centres for the operational AU fleet and several are studying Australian manufacturing capacity in response to the offshore wind project pipeline.
Vestas Asia Pacific — service centre in Melbourne. Vestas is the largest installed-base operator in Australia by capacity and is the most likely candidate for a future Australian blade or nacelle plant if the offshore pipeline materialises.
Siemens Gamesa Renewable Energy — international OEM with Australian project presence and offshore wind interest, particularly in Bass Strait and the Illawarra zones.
GE Renewable Energy — international OEM and Vestas competitor with Australian project presence.
Goldwind Australia — international OEM with a Sydney service centre and a significant onshore installed base.
Nordex Acciona — Spanish-headquartered international OEM with Australian onshore project deployments and a service presence.
Sany Heavy Industry — referenced here as an international precedent for vertically integrated wind manufacturing; Sany operates wind blade and tower facilities internationally and is the kind of vertically integrated operator whose model is sometimes cited in Australian feasibility studies.
For HVAC ductwork scopes the practical near-term opportunity with these operators is in service-centre upgrades — paint shop refurbishment, welding fume extract on tower repair work, and comfort HVAC in expanded warehouse and training facilities. The full-plant blade-plant opportunity is on the medium-term horizon.
Battery and storage
Energy Renaissance — Tomago NSW lithium battery cell and pack manufacturing operation, currently the most advanced Australian-owned lithium battery manufacturer. The HVAC scope at a lithium cell or pack plant is dominated by dry-room construction (cell production must be conducted in ultra-low humidity dry rooms, typically below 1 % RH), solvent extract on the electrode coating line, and electrolyte filling station extract. We cover this in more depth in the dedicated battery gigafactory HVAC ductwork guide.
Recharge Industries — Geelong-based lithium battery manufacturing operation, formerly affiliated with UECC. Similar HVAC scope to Energy Renaissance.
Calix — Bacchus Marsh VIC manufacturer of advanced battery materials including lithium iron phosphate cathode materials and Leilac (low-emissions calcium calcination) technology. Calix combines a process plant (calcination kiln) with a battery materials manufacturing operation; the HVAC scope crosses heavy-process ventilation (kiln stack, cooling air) and battery-materials cleanroom supply.
1414 Degrees — South Australian developer of thermal energy storage using molten silicon as the storage medium. HVAC scope is industrial process ventilation on the high-temperature reactor enclosure.
VRB Energy and Australian Vanadium — vanadium flow battery manufacturers, with Australian Vanadium based in Geraldton WA anchoring the vanadium concentrate supply chain. Flow battery manufacturing requires acid-resistant ductwork (the electrolyte is concentrated vanadium sulphate solution) — 316L stainless with PVDF lining is typical in the electrolyte handling zone.
Lithium battery materials manufacturers including Liontown and Allkem are covered in a separate battery gigafactory guide because the HVAC scope at a battery materials plant is distinct from the cell and pack plant scope.
Hydrogen and electrolyser manufacturing
Fortescue Future Industries — has announced plans for hydrogen electrolyser manufacturing capacity at Gladstone in Queensland. The HVAC scope at an electrolyser fabrication plant is dominated by Zone 1 hydrogen hazardous-area classification on the test bay, where stacks are pressure-tested with hydrogen before shipment. Duct material is 316L stainless with all-welded construction and IECEx-certified fans throughout the hydrogen-handling envelope.
Hyzon Motors Australia — fuel cell developer with Australian operations, focused on heavy-vehicle fuel cell propulsion. Fuel cell stack assembly is a clean-ambient operation with comfort HVAC; the hydrogen test bay carries the full Zone 1 classification.
HZWA consortium — Western Australian hydrogen value-chain consortium with electrolyser fabrication ambitions.
EPC and fabrication partners
The HVAC ductwork installer on a renewable manufacturing plant is typically a specialist subcontractor to one of a small group of EPCs or mechanical fabrication contractors. The names that recur across the Australian renewable manufacturing pipeline are Worley (international engineering and EPC, strong presence in hydrogen and ammonia), Civmec (heavy fabrication, particularly active in wind tower and offshore module work), Monadelphous (resources and energy EPC with a significant renewable backlog), and ASF Group (specialist mechanical and HVAC contractor on a range of renewable manufacturing projects). HVAC ductwork machinery suppliers like SBKJ engage either with these EPCs directly or with the HVAC fabrication subcontractor they appoint.
Duct material selection — the chemistry that drives the decision
The single most expensive mistake in renewable manufacturing HVAC is specifying the wrong duct material. The cost differential between galvanised and 316L stainless is significant (roughly 3–4x by mass at 2026 metal prices), but the consequence of getting it wrong is a duct replacement campaign 2–5 years post-commissioning, plus the upstream contamination of the product. The decision tree below is the SBKJ default.
When galvanised is acceptable
- Comfort HVAC in office, training, canteen, PPE and other non-process zones.
- Layup hall supply ductwork where the contaminants are dry fibre dust at low concentration.
- Sandblast bay extract (paired with replaceable wear liners at elbows).
- Aluminium swarf extract on solar module framing.
- Nacelle assembly bay general HVAC.
- Tower fabrication general HVAC outside the paint shop.
- Cleanroom supply ductwork (with internal cleanroom-grade sealant).
When 316L stainless is mandatory
- Paint booth supply and extract throughout the booth envelope (NFPA 33).
- Resin mixing and dispensing local exhaust.
- Blade infusion local exhaust capture.
- Cure oven exhaust for the first 6–10 metres downstream.
- Solar module laminator extract throughout.
- PV cell wet-bench acid fume extract (with PVDF lining on fluorinated acid paths).
- PECVD exhaust on cell lines.
- Hydrogen electrolyser test bay extract.
- Vanadium flow battery electrolyte handling.
- Junction box bonding station extract on solar module lines (acetic acid).
When conductive ductwork is required
- Carbon fibre dust collection on blade trim and finishing per NFPA 484.
- Glass fibre dust collection where the dust hazard analysis identifies risk.
- EVA encapsulant trim dust on solar module lines.
- Any dust collection system where the Dust Hazard Analysis identifies a Zone 21 or Zone 22 atmosphere.
SBKJ supplies conductive ductwork in two configurations: carbon-black-loaded conductive polymer or composite duct for the low-pressure-drop sections, and all-steel-mesh conductive duct (essentially a continuously bonded steel mesh embedded in the duct wall) for the high-pressure-drop or wear-critical sections. Both maintain bonded continuity along the full duct length and both are NFPA 484-compliant when correctly grounded.
Why galvanised fails in resin and paint zones — three mechanisms
The decision to use 316L stainless rather than galvanised in paint and resin zones is not an over-specification — it is the result of three distinct failure mechanisms that we have observed in the field.
Mechanism 1 — epoxy resin attack on zinc. Epoxy resin systems and their hardeners are mildly to moderately corrosive to zinc, particularly at the resin-rich condensate film that forms on duct internal surfaces. The reaction product is a zinc complex that flakes off and contaminates the resin pot if it migrates upstream. The flake also generates a porous surface on the duct wall that accelerates further corrosion.
Mechanism 2 — MEKP catalyst attack. Methyl ethyl ketone peroxide (MEKP), used as the catalyst in some toughened epoxy and most polyester resin systems, is an aggressive oxidiser that attacks zinc directly, generating zinc soap residues that contaminate the resin and accelerate duct seam failure. MEKP vapour at the layup station can perforate galvanised duct at the longitudinal seam within 12–24 months of commissioning.
Mechanism 3 — solvent condensation at seams. The styrene, acetone and other solvents present in resin and paint zones condense on cool duct internal surfaces during temperature swings. The condensate concentrates at the duct seam and degrades the galvanising along the seam line. Continuous welded 316L stainless eliminates the seam-line vulnerability and the solvent attack.
Spray application and NFPA 33 — what the paint shop has to look like
Wind turbine blade paint shops, tower paint shops and any other heavy-coating operation in the renewable manufacturing stack must satisfy NFPA 33 in design, even where the Australian regulator's primary reference is AS 4114. The NFPA 33 design intent is straightforward: contain the flammable vapour cloud, ventilate it to outdoor stack at safe dilution, eliminate ignition sources from the vapour envelope, and protect the rest of the building from a booth event.
The booth itself is a vapour-tight enclosure with downdraft airflow. Air is supplied at the ceiling through HEPA-filtered or paint-arrestor-filtered plenums, flows downward across the workpiece, and returns through the floor either to a water curtain (wet booth) or to dry filter banks (dry booth). The floor return air is then ducted up an outboard riser to the fan, with the fan located outside the booth envelope to ensure that any motor or bearing ignition source cannot reach the vapour. From the fan, the exhaust goes to the stack — which must discharge upward, terminate at the minimum NFPA 33 distance above the roof, and be located the minimum NFPA 33 distance from any building intake.
Booth construction is welded steel with vapour-tight joints. Booth doors are interlocked with the fan such that the booth cannot be operated without ventilation; conversely, the ventilation continues for a purge cycle after spray finish before the booth doors can be opened. Booth lighting is sealed fixtures rated for the zone classification — typically Zone 1 in the vapour space during spray operations. Any electrical equipment inside the vapour envelope is ATEX or IECEx rated. The duct is 316L stainless throughout the booth and the supply ductwork serving the booth. The wet curtain return — if specified — uses 316L stainless throughout because the water captures the overspray solids and forms an aggressive slurry over time.
Booth makeup air conditioning is a project in its own right. The blade paint shop runs to a tight humidity envelope (typically 50 ± 5 % RH) because polyurethane and fluoropolymer topcoats are humidity-sensitive at cure. Australian climate variation between winter and summer requires both heating and cooling capacity on the makeup air handler; large blade paint shops often run dedicated makeup air handlers in the 100–200 kW thermal range per booth.
Combustible dust and NFPA 484 — the carbon fibre case
NFPA 484 is the controlling standard for combustible dust on the blade line, and carbon fibre dust is the test case. Carbon fibre is both combustible and electrically conductive — the latter property means that even a small ingress of dust into electrical equipment can short-circuit and ignite the dust. Glass fibre dust is less hazardous (it is not combustible at typical bulk density) but is treated to a similar standard at most Australian blade plants because the dust collection system serves both fibre types.
Dust Hazard Analysis (DHA)
NFPA 484 requires a Dust Hazard Analysis for every facility handling combustible dust. The DHA identifies the dust composition, particle size distribution, minimum explosible concentration (MEC), minimum ignition energy (MIE), Kst (deflagration index) and electrical resistivity. The DHA outputs drive the duct, isolation device, baghouse vent and stack design. A blade plant DHA typically lists carbon fibre dust as a Class IIIB combustible dust with low MIE (often under 10 mJ), which sets the design at the most stringent end of the NFPA 484 envelope.
Duct construction for carbon fibre dust
Conductive ductwork is mandatory. SBKJ supplies the conductive duct in two configurations as described above. Duct routing eliminates internal pockets, dead legs, sharp transitions and any feature that can accumulate static dust deposits. Cleanouts are provided at every major bend and at intervals along long horizontal runs. Duct velocity is maintained above the dust transport minimum (typically 17–22 m/s for fibre-based dusts) so that no deposition occurs in the duct itself. Duct grounding is continuous along the length with bonded continuity verified at commissioning and re-verified at scheduled intervals.
Explosion isolation and venting
Explosion isolation devices — chemical-suppression isolation valves, mechanical fast-acting valves, or rotary valve-style isolators — are installed upstream of the baghouse to prevent any deflagration in the baghouse from propagating back along the ductwork into the production hall. The baghouse itself is explosion-vented (rupture panels sized per NFPA 484) and located outside the building envelope with the minimum separation distance from occupied buildings. Discharge from the explosion vents is directed to a clear zone away from personnel access.
Fan selection
Spark-resistant AMCA Type B or Type C fans are required, depending on the DHA-derived risk category. The fan is located after the baghouse in the air path (clean-side fan) so that the dust load passes through the bag filter before reaching the fan impeller, and not before. Motors are ATEX or IECEx certified for the Zone 22 dust atmosphere classification.
Solar module lamination extract — the acetic acid problem
The single most under-appreciated HVAC risk on a solar module assembly line is the acetic acid generated by EVA encapsulant decomposition during lamination. Every laminator cycle releases a small mass of acetic acid into the extract air. Cumulatively over months and years, that acetic acid condenses on duct internal surfaces, drips down to the duct floor, and aggressively attacks galvanised duct from the inside.
The failure mode is well documented at older solar module plants worldwide and the duct lifespan on a galvanised laminator extract is typically 3–5 years before perforation begins. The remediation cost — including production downtime, scaffolding access, disposal of the contaminated old duct, and installation of the replacement — typically exceeds the original capital cost by 2–3x. The SBKJ default is 316L stainless throughout the laminator extract from day one, with continuous welded longitudinal seams (TIG welded) and full pressure testing before commissioning. The stainless duct lifespan is 20+ years and the installation cost premium pays back through the avoided remediation alone.
Downstream of the laminator, the encapsulant trim station generates EVA dust that is moderately combustible. NFPA 484 may apply at high enough dust loading — the DHA is the determining document. Where the DHA identifies the trim station as a Zone 22 dust atmosphere, conductive ductwork is appropriate; where the DHA places it below the Zone 22 threshold, standard 316L stainless duct is sufficient.
Hydrogen electrolyser fabrication — the Zone 1 hydrogen test bay
Electrolyser stack manufacturing is mostly clean-ambient assembly work — stack components are bonded, gasketed and bolted together in a controlled environment. The HVAC scope at the assembly bay is comfort HVAC with elevated cleanliness standards, typically galvanised duct with cleanroom-grade sealant.
The Zone 1 hazardous-area scope is concentrated at the stack test bay, where assembled stacks are pressure-tested with hydrogen before shipment. Hydrogen is the most challenging gas to contain because of its small molecular size and wide flammability range (4–75 % in air, the widest of any common gas). The test bay is enclosed, ventilated at high air-change rate (typically 12–20 ACH or higher depending on the local hydrogen release risk assessment), and continuously monitored with hydrogen detection at multiple points. All ventilation equipment in the bay envelope is IECEx-certified for Zone 1 hydrogen gas group IIC and temperature class T1. Duct material is 316L stainless with all-welded construction (no mechanical seams) because hydrogen leaks through any seam, gasket or coupling that is not weld-sealed.
The Fortescue Future Industries Gladstone manufacturing announcement, the Hyzon Motors fuel cell operation and the HZWA consortium projects are all examples of facilities that will require this scope. SBKJ's standard configuration for hydrogen electrolyser fabrication is the SBAL-V auto duct line configured for 316L stainless coil, paired with a TIG longitudinal seam welder for continuous welded duct construction.
Acoustic design — NC-50 industrial and NC-40 clean assembly
Renewable manufacturing plants are acoustically demanding because the production processes are continuous, the noise sources are diverse (fans, baghouses, autoclaves, presses, robotic arms, ventilation supply diffusers), and the workforce spends full shifts on the floor. The industry default is NC-50 in the general production hall and NC-40 in the clean assembly bays, with stricter targets in the office and training zones.
Duct silencers are installed at every major fan discharge into the building envelope. Lined plenums are specified at every diffuser bank in the clean assembly bays. Risers serving high-noise extract systems (paint booth, dust collection, lamination extract) are lagged with acoustic insulation to prevent break-out noise. The acoustic design is layered on top of the hazardous-area and material selection — silencer construction in a paint booth supply, for example, must be 316L stainless throughout because the silencer is inside the booth envelope.
SBKJ machine configuration for a renewable manufacturing plant
The duct quantities on a single renewable manufacturing plant are large enough that a dedicated SBKJ machine package is almost always the right answer rather than buying duct from a third-party fabricator. The standard SBKJ renewable-plant configuration is:
SBAL-V auto duct production line in 316L stainless
The SBAL-V auto duct production line is configured for stainless coil processing, with material handling, slitting, notching and Pittsburgh-seam forming all calibrated for 316L stainless steel feedstock. The SBAL-V runs paint shop duct, resin zone duct, cure oven downstream duct, solar laminator extract, hydrogen test bay duct and any other 316L stainless rectangular ducting on the plant. The same line, after a coil change, runs galvanised AS/NZS 4254 duct for the comfort HVAC and non-aggressive process zones. One machine, both materials, the whole plant.
SBTF-2020 spiral tubeformer for large-bore dust mains
The SBTF-2020 spiral tubeformer produces round spiral duct from 80 mm to 2,000 mm internal diameter. Large-bore dust mains feeding the carbon fibre baghouse, the EVA trim baghouse and the sandblast baghouse are typically 600–1,500 mm diameter spiral duct, and the SBTF-2020 in stainless produces the full range. Spiral duct is preferred over rectangular for dust handling because the helical seam is more resistant to deposit accumulation and because the round cross-section maintains uniform velocity around the duct perimeter.
TIG longitudinal seam welder for continuous welded duct
For the highest-aggression zones — solar laminator extract, hydrogen test bay duct, paint shop wet curtain return — Pittsburgh-seam construction is not adequate because the seam can leak under solvent or acid attack. A dedicated TIG longitudinal seam welder produces continuous fully welded duct in 316L stainless, with full pressure testing before commissioning. The welder integrates into the SBAL-V line for high-throughput continuous duct manufacture.
Conductive duct option for combustible dust
SBKJ offers two conductive duct options for the carbon fibre and combustible-dust scopes. The carbon-black-loaded composite duct is appropriate for low-pressure-drop sections and is supplied as flexible-format duct in pre-bonded continuous lengths. The all-steel-mesh conductive duct embeds a continuously bonded steel mesh in the duct wall and is appropriate for high-pressure-drop sections and any wear-critical zone. Both are supplied with grounding lugs at standard intervals for bonded continuity verification.
A worked example — a 50,000-square-metre blade plant
To make the SBKJ machine configuration concrete, consider a hypothetical 50,000-square-metre blade plant producing 80-metre offshore wind blades at a rate of one blade per day. The HVAC scope breaks down approximately as follows:
- Comfort HVAC — offices, training, canteen, PPE rooms, locker rooms — approximately 8,000 square metres at 0.5 kg/m² duct mass = 4,000 kg of galvanised duct. SBAL-V on galvanised coil.
- Layup hall supply — 18,000 square metres of conditioned layup hall — approximately 22,000 kg of galvanised rectangular duct. SBAL-V on galvanised coil.
- Resin and paint zone duct — paint booths (two booths at 30 m × 12 m × 8 m), resin mix bay, layup local exhaust risers — approximately 12,000 kg of 316L stainless rectangular duct. SBAL-V on 316L coil, with TIG welder on the highest-aggression sections.
- Cure oven and post-cure duct — first 6–10 m of cure oven exhaust, post-cure transitional duct — approximately 3,000 kg of 316L stainless duct.
- Dust collection mains — carbon fibre and glass fibre dust mains feeding the explosion-vented baghouse — approximately 8,000 kg of conductive spiral duct in diameters from 400 mm to 1,200 mm. SBTF-2020 on conductive material.
- Sandblast bay extract — heavy-gauge carbon steel with wear liners — approximately 5,000 kg.
- Welding fume extract — local capture at every welding station — approximately 2,000 kg of galvanised round duct. SBTF-2020 on galvanised coil.
The total duct mass is approximately 64,000 kg, of which roughly 15,000 kg is 316L stainless, 8,000 kg is conductive duct, 5,000 kg is heavy carbon steel, and the balance (approximately 36,000 kg) is galvanised. A single SBKJ SBAL-V production line, paired with an SBTF-2020 spiral tubeformer and a TIG seam welder, fabricates the entire scope over a 4–6 month manufacturing window. The duct fabrication cost as a fraction of total HVAC cost on a plant of this scale is typically 18–25 %.
Future Made in Australia and the policy backdrop
The Future Made in Australia (FMIA) programme, announced in the May 2024 federal budget at AUD 22.7 billion over 10 years, underwrites domestic production of green hydrogen, critical minerals, low-emissions aluminium, solar PV components and battery components. The programme combines production tax credits, capital grants and concessional finance through the Clean Energy Finance Corporation and the National Reconstruction Fund.
For renewable manufacturing HVAC, FMIA has converted speculative feasibility studies into funded engineering work, prompted matching state-level incentives in dedicated precincts (Hunter NSW, Gladstone QLD, Geelong VIC, Geraldton WA, South Australian hydrogen hubs), and built a domestic policy floor under offshore wind — the structural demand catalyst for any future Australian blade and nacelle plant.
For HVAC ductwork suppliers, the practical implication is that the renewable manufacturing pipeline is now multi-year and multi-site. A duct fabrication operation that learns the standards stack and the duct material chemistry will have a credible offering across solar module, battery, hydrogen and — eventually — wind component plants. SBKJ has built the renewable-plant package around this expectation.
Procurement checklist — what to verify before signing
The SBKJ engineers walking customers through a renewable manufacturing HVAC scope have converged on a short procurement checklist that filters out the most common specification errors. We reproduce it here as a single page.
Compliance and standards
- AS 1668.2 industrial ventilation calculation completed and signed by the consulting engineer for every process zone.
- AS/NZS 60079 hazardous-area classification drawing produced and signed.
- NFPA 33 spray application review for every paint booth and resin spray operation.
- NFPA 484 Dust Hazard Analysis for every combustible-dust operation, with output mapped to duct, isolation and venting design.
- IEC 61400 cross-reference for blade plant ventilation against the OEM manufacturing specification.
- ASTM D3878 terminology applied consistently across the design documentation.
Material specification
- 316L stainless coil specified for all paint, resin, lamination, hydrogen and acid-handling extract paths.
- Conductive ductwork (carbon-black-loaded or steel-mesh) specified for all combustible-dust paths per NFPA 484.
- Galvanised coil specified for comfort HVAC and non-aggressive process zones.
- Heavy-gauge carbon steel with wear liners specified for sandblast extract.
- Mill certificates required for all stainless coil; ISPM-15 stamp required on all crating.
Construction class
- AS/NZS 4254 Class B for rectangular comfort HVAC.
- Spiral duct or longitudinal welded round for dust and process extract.
- Continuous welded longitudinal seam (TIG welded) for paint shop, resin vapour, laminator extract and hydrogen test bay.
- Pressure testing protocol agreed before fabrication for all welded duct.
Hazardous-area equipment
- ATEX or IECEx certification verified for all fans, motors, dampers and instrumentation in classified zones.
- Gas group (IIA, IIB, IIC) and temperature class (T1, T3, T4) specified per zone.
- Spark-resistant AMCA Type B or C fan specification confirmed for combustible-dust extract.
Acoustic and comfort
- NC-50 industrial design target for production stages; NC-40 for clean assembly bays.
- Silencer specification at every fan discharge into the building envelope.
- Lined plenums at every diffuser bank in clean assembly zones.
- Acoustic lagging on risers serving high-noise extract systems.
Commercial
- 30/70 T/T or L/C at sight payment terms.
- CIF Melbourne or FOB origin port Incoterm specified at quotation.
- Factory Acceptance Test scheduled with buyer attendance.
- Spare parts package for one year of operation included with the machine.
- Installation supervision package of 5–10 days included.
Get an SBKJ renewable-plant machine package quote →
FAQ
What is the most important HVAC standard for an Australian wind turbine blade plant?
AS 1668.2 governs the industrial ventilation rate. AS/NZS 60079 series classifies hazardous areas around resin and solvent stores. NFPA 33 covers spray application booths. NFPA 484 controls combustible dust hazards for carbon fibre and glass fibre dust collection. IEC 61400 is the international wind turbine reference and ASTM D3878 covers composite material terminology. A compliant blade plant must satisfy all five — galvanised duct meets none of them in resin or paint zones.
Why does galvanized duct fail in a wind turbine blade plant?
Three reasons. Epoxy resin and the MEKP catalyst attack the zinc layer and produce zinc soap residues that contaminate the layup. Solvent vapours condense on cool duct surfaces and degrade galvanising at the seam. NFPA 484 requires conductive ductwork in carbon fibre dust collection — galvanised duct does not maintain bonded continuity once the zinc oxidises. SBKJ specifies 316L stainless for paint and resin zones, and conductive duct for fibre dust.
Which Australian manufacturers should we approach for renewable equipment fabrication work?
On the solar side, 5B Generators in Sydney, SunDrive Solar, and Bridie Wave / SwitchedOn Solar. On the wind side, international OEMs such as Vestas Asia Pacific, Siemens Gamesa Renewable Energy, GE Renewable Energy, Goldwind Australia and Nordex Acciona operate service centres in Australia. On the battery side, Energy Renaissance, Recharge Industries, Calix, 1414 Degrees and VRB Energy. On hydrogen, Fortescue Future Industries, Hyzon Motors Australia and the HZWA consortium. EPC partners include Worley, Civmec, Monadelphous and ASF Group.
What SBKJ machine configuration is right for a renewable manufacturing plant?
The standard SBKJ renewable-plant package is an SBAL-V auto duct production line configured for 316L stainless coil, an SBTF-2020 spiral tubeformer in stainless for large-bore dust mains, and a dedicated TIG longitudinal seam welder for hygienic continuous welded duct. The SBAL-V also runs galvanised duct for comfort HVAC, so one line covers the whole factory.
What is Future Made in Australia and how does it affect this sector?
FMIA is the AUD 22.7 billion federal programme announced in the 2024 budget to underwrite Australian renewable, critical minerals and battery manufacturing. It funds production tax credits, manufacturing grants and capital support. Combined with state-level renewable manufacturing precincts and offshore wind project pipelines, it is the structural reason that domestic blade and nacelle manufacturing capability is now under serious commercial study.
