Marine Yacht Boatbuilder HVAC Duct Guide — Riviera Coomera, Maritimo, SilverYachts Henderson WA, NFPA 484 Aluminium, Styrene Extraction, AS 4254

Why marine boatbuilder HVAC is the hardest mixed-process ventilation job in Australia

Walk through Riviera at Coomera, Maritimo at Hope Island, Whittley Marine at Lara VIC or SilverYachts at Henderson WA and you will find — under one roof — every demanding ventilation problem in Australian manufacturing stacked on top of each other. Polyester resin layup generating styrene at 50 ppm WES alongside two-pack polyurethane topcoat generating isocyanate at 0.005 ppm WES alongside aluminium grinding generating combustible metal dust under NFPA 484 alongside diesel engine dyno commissioning generating CO at 30 ppm WES alongside marine-grade chloride atmosphere attacking everything zinc-galvanised within five years. A typical Australian production boatbuilder runs eight to twelve distinct ventilation problems in parallel. An automotive paint shop runs three. A pharma cleanroom runs two. A boatbuilder shed is the hardest mixed-process ventilation job our SBKJ engineering team scopes anywhere in the country.

This guide is the same engineering reference our SBKJ application team uses when a Boating Industries Alliance Australia (BIAA) member or an AIMEX export superyacht builder asks how to size duct fabrication for a boatbuilder fit-out. We have built the duct fabrication machinery on jobs ranging from a single fibreglass catamaran kit-builder in NSW through to multi-bay aluminium plate boat lines and 80 m superyacht assembly halls. The patterns repeat. The standards stack — AS 4114.2 over AS 1668.2 over AS/NZS 60079 over AS 3957 over NFPA 484 over ISO 12215 over NSCV — is the most layered regulatory stack we handle outside aerospace. Get the standards stack right and the rest of the design follows.

Seven conditions make marine boatbuilder HVAC harder than other industrial ventilation. First, the multi-toxicant problem — styrene, isocyanate, epoxy amine, solvent VOC, aluminium dust and engine CO all coexist in adjacent zones and the LEV system must capture each one without cross-contamination. Second, the combustible metal hazard — aluminium fines from grinding 5083, 5086 and 6061 marine plate are NFPA 484 Class D combustible metals with water reactivity (Al plus H2O produces aluminium hydroxide plus hydrogen gas), which restricts water deluge suppression and demands specialist Class D extinguishing media. Third, the hazardous area density — every boatbuilder has at least four AS/NZS 60079 zones (spray booth Zone 1, resin store Zone 2, fuel bunker Zone 1, LPG forklift charging Zone 2) plus AS 3957 dust zones around aluminium grinding. Fourth, the corrosion environment — coastal sheds at Coomera, Henderson, Brisbane, Yamba and Caboolture sit in chloride-laden marine atmosphere that destroys galvanised supply duct within 5 to 8 years if specification is wrong. Fifth, the dimensional scale variability — the same builder may run 4 m tinnies on Monday and 25 m motor yachts on Wednesday, with airflow requirements differing tenfold between the two. Sixth, the engine commissioning load — every diesel engine inboard installation requires dyno run-up before sea trial, generating 350 to 450 C exhaust gas that must be captured and stacked above roof. Seventh, the export compliance overlay — Australian boats are exported to the EU under CE-marked RCD, to the USA under ABYC and USCG CFR 33/46, and the ventilation envelope of the build shed must satisfy AS 4114.2 plus the relevant overseas standard where the destination AHJ requires it.

The Australian marine boatbuilder landscape — Coomera, Henderson, Sydney, Lara and Tasmania

Australian boatbuilding concentrates in five geographic clusters, each with distinct product mix, scale and ventilation challenge. Understanding the cluster pattern is the starting point for any duct machinery procurement decision in the sector.

Coomera marine precinct, Gold Coast QLD. The single largest boatbuilding cluster in Australia and one of the largest in the southern hemisphere. Riviera Australia at Coomera is the country's biggest motor yacht builder, producing 39 to 72 ft luxury motor yachts at a rate that has run consistently above 100 hulls per year — the company's main yard is a multi-bay production line with parallel fibreglass mould rooms, isocyanate topcoat booths, marine fit-out joinery shop, electronics fit-out clean zone and engine commissioning bay. Maritimo at Hope Island and Coomera, founded by Bill Barry-Cotter (formerly of Riviera), builds 50 to 75 ft luxury motor yachts on a parallel multi-bay production line. Quintrex (Telwater subsidiary of BRP) at Coomera builds aluminium tinnies and plate boats from 3 to 7 m at high volume. Stacer (also Telwater BRP) shares the same precinct for aluminium fishing boats. Cruise Craft at Coomera builds luxury aluminium trailer boats. Lightwave Yachts at Coomera builds Australian-built catamarans. Sanctuary Cove sits adjacent and hosts the Sanctuary Cove International Boat Show, the largest on-water boat show in the southern hemisphere. The Boat Works and Riviera Service Centre at Coomera handle refit and warranty work. Marine Queensland is the state body coordinating the precinct.

Henderson, Perth WA. Australia's superyacht and naval shipbuilding cluster. SilverYachts (Henderson) builds Silver Cloud at 134 m and other commercial-scale superyachts up to 90 m — among the largest Australian-built private and commercial vessels. Echo Yachts (Henderson) built White Rabbit, the largest aluminium catamaran-trimaran superyacht in the world at 84 m. Civmec (Henderson) builds Hunter Class Frigates for the Royal Australian Navy and offshore platform structures. The Henderson Maritime Precinct includes Austal aluminium fast ferries (separate scope from the recreational sector). Henderson sheds are vast — 100 m by 50 m by 25 m high is a typical scale for superyacht assembly — and the ventilation load reaches 100 to 200 m3/s installed for a full superyacht builder.

Brisbane and South-East Queensland. Rivergate Marina and Shipyard at Murarrie Brisbane is one of the country's largest marine refit yards, supporting commercial and recreational vessels up to 80 m. Norman R. Wright and Sons at Bulimba QLD is a heritage timber and composite yard. Haines Hunter at Caloundra builds fibreglass walkaround offshore boats. Aussie Boatworks at Brisbane builds aluminium custom commercial and recreational vessels. Stessl Boats at Caboolture (acquired by Hyundai Marine) builds aluminium trailer boats.

Sydney and NSW. Haines Signature operates between Sydney and QLD on fibreglass trailer boats. Yamba Marine Centre at NSW handles refit and small build. AMI Marine Industries at Coffs Harbour NSW builds aluminium commercial vessels. Schionning Designs at NSW supplies catamaran kits and plywood-epoxy designs. Sea Land Air at NSW builds aluminium patrol and commercial vessels.

Victoria and Tasmania. Whittley Marine at Lara VIC builds fibreglass trailer boats. Hummingbird Boats at Tasmania builds aluminium plate fabrication for commercial and recreational. Sailing yacht importers (Beneteau Australia, Jeanneau Australia, Fountaine Pajot Australia, Catana Australia) operate refit and commissioning yards in VIC and NSW.

Each cluster has a distinctive process mix. Coomera is fibreglass-dominated with aluminium trailer boat overlay. Henderson is aluminium-dominated for superyacht scale. Brisbane is refit-mixed. NSW is composite kit and small commercial. Tasmania is aluminium plate. The ventilation design must match the cluster's process mix and the shed's destination market.

Marine process zones — eight distinct ventilation problems under one roof

Inside a typical Australian production boatbuilder there are eight sequential or parallel process zones, each with its own ventilation signature. The duct designer must size supply and exhaust for each zone independently and verify there is no zone-to-zone cross-contamination.

Pattern, tooling and mould making. CAD-driven 5-axis CNC cutting of timber, aluminium or composite plug, fillers, PVA wax, release agent application and gel coat surface preparation. Air supply at 4 to 6 ACH general dilution, localised dust extraction at sanding stations at 0.5 to 1.0 m/s capture velocity. Galvanised supply duct, polypropylene or 316L stainless on release-agent solvent exhaust. The mould room temperature must hold 22 C plus or minus 2 to ensure stable resin cure on first article hulls.

Fibreglass gel coat, hand layup and VARIM. The single highest-volume ventilation zone in a production boatbuilder. Gel coat is sprayed onto the open mould at 0.4 to 0.6 m/s capture velocity at a canopy hood directly above the mould edge. Hand layup follows with polyester or vinylester resin (styrene at 50 ppm WES TWA, 100 ppm STEL) catalysed with CR (cumene hydroperoxide or MEKP). Vacuum-assisted resin infusion (VARIM) and resin transfer moulding (RTM) reduce open emission by 70 to 90 percent versus open mould, but the vacuum exhaust line itself becomes the concentrated styrene source. Riviera, Maritimo, Quintrex's fibreglass cruisers (Yamaha-engined runabouts), Whittley Marine and Haines Hunter all run this process. Resin systems include Sika, Resoltech, SP Systems, West System and Mas Epoxy. Ductwork is 316L stainless or polypropylene because polyester resin attacks galvanised zinc within 12 months. NFPA Class A combustible flammable liquid handling rules apply to the resin store and gel coat supply, with spark-free electrical and full equipotential grounding.

Composite prepreg, vacuum bag and autoclave. Race and performance yacht and high-end catamaran (Echo Yachts trimaran, Beneteau Australia composite work, Schionning composite kits). Carbon fibre reinforced polymer (CFRP), glass-reinforced polymer (GRP) and Kevlar aramid laminates. Autoclave cure at 80 to 120 C and 2 to 4 bar absolute pressure under nitrogen blanket. Post-cure VOC emission of epoxy thinner, IPA, MEK and ethyl acetate during cure ramp-up. Layup room cleanliness ISO 8 ambient or unclassified clean. Ductwork 316L stainless on autoclave vent line.

Aluminium cut, form, weld and rivet. Telwater Quintrex tinnies, Stessl plate boats, Stacer fishing boats, SilverYachts superyacht hulls, Echo Yachts catamaran trimaran, Civmec naval, Aussie Boatworks commercial, Sea Land Air patrol craft and Hummingbird Tasmania commercial. Marine-grade 5083, 5086 and 5052 alloy plate plus 6061 and 6082 structural extrusion. CNC plasma, water jet, laser, brake press and pulse MIG/TIG welding. Welding fume contains aluminium (1 mg/m3 WES inhalable), aluminium oxide, manganese (0.2 mg/m3 respirable), chromium (welding 5083 with 5XXX filler does not generate significant Cr) and ozone. Aluminium fines from grinding and polishing are NFPA 484 combustible metal Class D with Kst 200 to 415 bar.m/s. Dust extraction at 18 to 23 m/s transport velocity to a wet collector or dry collector with explosion suppression. Class D extinguishing media (Met-L-X, Pyrene G-Plus) at every grinding station — water deluge restricted because Al plus H2O produces hydrogen gas.

Paint booth, anti-fouling and topcoat application. Two-component polyurethane topcoat from Awl-Grip, Imron, International, Hempel, Jotun and Pettit with isocyanate (TDI, MDI) at 0.005 ppm WES. Anti-fouling paint application below waterline with copper-based biocide (TBT banned since 2008). Spray booth Zone 1 per AS/NZS 60079 with downdraft at 0.4 to 0.5 m/s for OEM superyacht topcoat and cross-draft at 0.5 to 0.6 m/s for production motor yacht. Post-cure bake at 50 to 60 C drives off residual solvent. Ductwork 304L or 316L stainless because isocyanate aerosol and amine accelerator attack zinc.

Engine install, commissioning, sea trial and tank test. Cummins QSB6.7 through QSK19, CAT C18 and C32, MTU 8V/12V/16V 2000 series and 4000 series, MAN V8/V12, Volvo Penta IPS and D-series, Yamaha and Suzuki and Mercury and Honda outboards, Yanmar marine inboards. Diesel dyno test at 150 to 800 kW per engine generates 350 to 450 C exhaust containing CO (30 ppm WES), NO2 (3 ppm STEL), respirable particulate and unburnt hydrocarbons. Fuel bunker on-vessel ranges 500 to 50,000 L per build under AS 1940 flammable liquid handling. Engine commissioning shed must be 8 to 10 m high to allow stack discharge above roof. Stack ductwork 316L stainless with bellows expansion joints.

Timber and epoxy cold-mould. Rare in production volume but present at Lloyd Stevenson, Schionning, traditional superyacht and bespoke catamaran builds. Western Red Cedar, Khaya mahogany, plywood-epoxy laminate. Mas Epoxy, West System, SP Systems and Sika resin. Sanding generates timber dust and uncured epoxy aerosol. Localised dust extraction at every sanding station with HEPA pre-filter. Ductwork galvanised or polypropylene.

Rig, electronics, instrument fit-out, marine joinery, generator and battery room. Garmin, Raymarine, Furuno and Simrad marine electronics fit-out in a clean ESD-safe zone. Stainless rigging from Schaeffer Marine, Lewmar Australia, Andersen, Selden. Custom timber and veneer joinery with contact cement (toluene 50 ppm WES, MEK 200 ppm), formica, leather and high-pressure laminate. AGM, gel and lithium-ion LiFePO4 marine batteries — H2 evolution during charging triggers AS/NZS 60079 Zone 2 classification in the battery room. Ventilation supply at 4 to 6 ACH plus localised joinery dust extraction. Galvanised supply duct, 316L stainless on the marine generator and battery room because chloride-laden marine atmosphere reaches the room interior.

Codes and standards — the marine boatbuilder regulatory stack

No marine boatbuilder ventilation design is complete without explicit verification against a stack of overlapping standards. The fifteen references below are the primary references for Australian boatbuilder fit-outs; in any given project at least eight apply and often all fifteen.

AS 4114.2 — Spray painting booths, designated areas and other enclosures. The Australian equivalent of NFPA 33 for spray booth construction and ventilation. Section 3 covers booth construction and materials, section 4 covers ventilation requirements including face velocity for cross-draft and downdraft, section 5 covers electrical including AS/NZS 60079 Zone 1 inside the booth, section 6 covers fire protection. The face-velocity floor of 0.5 m/s in section 4 aligns with NFPA 33 chapter 7. AS 4114.1 covers booth selection guidance and AS 4114.3 covers booth testing. Every marine isocyanate topcoat booth at Riviera, Maritimo, Cruise Craft, Lightwave Yachts and the superyacht builders is designed to AS 4114.2.

AS 1668.2 — The use of ventilation and air-conditioning in buildings. Section 2 sets minimum outdoor air rates for occupied spaces and section 4 sets specific requirements for industrial processes including marine fibreglass layup, aluminium welding and dust collection. Cross-references AS 4114.2 for spray-specific requirements.

AS 4254 (parts 1 and 2) — Ductwork for air-handling systems in buildings. Part 1 covers flexible duct and part 2 covers rigid duct. The standard sets pressure class, leakage class, materials, gauges, seam construction, joint construction and support requirements for the duct itself. All SBKJ machinery is configured to fabricate AS 4254 compliant duct as the default Australian output, with SMACNA pressure class equivalents available for export work.

AS 1530.3 and AS 1530.4 — Methods for fire tests on building materials, components and structures. Part 3 covers ignitability and part 4 covers fire resistance of building elements. Marine builder sheds with bake-out chambers, spray booths and resin stores are typically NCC Class 8 industrial occupancy with fire-resistance ratings ranging from 60 to 120 minutes on penetrations and 240 minutes on bake-out fire-rated runs. SBSF-1525 stitchwelder is the SBKJ machine for fire-rated heavy-gauge sections.

AS 1851 — Routine service of fire protection systems and equipment. Sets the maintenance schedule for fire and smoke dampers, sprinkler systems and detection. Boatbuilder sheds with isocyanate spray booths, resin stores, aluminium dust collection and engine commissioning bays carry the highest density of fire suppression and detection per square metre of any industrial occupancy.

AS/NZS 60079 (series) — Explosive atmospheres. The hazardous area zone classification standard covering Zone 0, 1 and 2 for gas and vapour atmospheres. Marine spray booth interior is Zone 1, booth surrounds are Zone 2, resin store is Zone 2, fuel bunker for on-vessel commissioning is Zone 1, LPG forklift charging is Zone 2, marine battery room with H2 evolution is Zone 2. Ductwork transiting hazardous zones must be bonded and grounded to less than 10 ohms with spark-free design at every penetration.

AS 1940 — The storage and handling of flammable and combustible liquids. Covers paint store, resin store, solvent store, fuel bunker and engine room bunker on commissioning. Sets bunding, ventilation, separation and fire-resistance rules.

AS 3957 — Hazardous areas, dust hazards. The dust analogue of AS/NZS 60079. Zone 20, 21 and 22 cover combustible dust atmospheres. Aluminium grinding dust around Quintrex, Stessl, Stacer, SilverYachts and Echo Yachts triggers Zone 22 around the dust collector and Zone 21 inside the collector itself. Composite carbon fibre and glass fibre dust around prepreg work triggers similar classification but with lower deflagration severity.

NFPA 484 — Standard for Combustible Metals. The international best-practice reference for aluminium handling, cross-referenced with NFPA 660 in the 2025 consolidation. Australian boatbuilders running aluminium follow NFPA 484 where AS 3957 does not provide explicit guidance. The standard covers dust collection design, explosion protection, ignition source control, water reactivity (Al plus H2O produces hydrogen) and Class D extinguishing media.

NFPA 660 (2025). The consolidated combustible dust standard that replaces NFPA 652, 654, 655, 664 and 484 in a single document. Boatbuilder fit-outs in 2026 reference NFPA 660 in parallel with the legacy NFPA 484 because some elements of NFPA 484 remain authoritative for combustible metal even after consolidation.

NFPA 86 — Standard for Ovens and Furnaces. Governs post-cure paint bake oven at 50 to 60 C, powder coat oven (rare in marine), epoxy paint cure and autoclave composite cure at 80 to 120 C and 2 to 4 bar absolute. Pre-purge, flame supervision, high-temperature limit and explosion relief apply scaled to the oven volume.

AS/NZS 1554 series — Structural steel welding. Part 1 covers carbon steel, part 6 covers stainless steel. Relevant for boatbuilder rig and winch hardware fabrication. AS 1665 covers aluminium welding.

ISO 12215 — Small craft hull construction. The international standard for FRP, aluminium, steel and composite hull design for vessels 2.5 to 24 m. The standard sets the load case and laminate or plate thickness requirements that drive resin volume, plate gauge and consequently the ventilation load on the build shed. Every Australian recreational boatbuilder building under 24 m hull length designs to ISO 12215.

CE marking Recreational Craft Directive 2013/53/EU. Required for any boat exported to the EU. The directive covers design, construction, exhaust emissions, noise emissions and stability. Australian boatbuilders exporting to the EU (Riviera, Maritimo, Whittley) build to RCD with notified body assessment.

AMSA, NSCV and ABP. Australian Maritime Safety Authority is the regulatory umbrella. NSCV (National Standard for Commercial Vessels) governs commercial vessel design and construction. Australian Builders Plate (ABP) regulation applies to all recreational craft under 6 m. ABYC American Boat and Yacht Council and USCG CFR 33 and 46 apply to USA export.

Fibreglass styrene extraction — the highest-volume ventilation problem in production boatbuilding

Styrene from polyester and vinylester resin is the single most demanding ventilation problem in any production boatbuilder running open mould or vacuum-assisted infusion. The Australian Workplace Exposure Standard (WES) sets the time-weighted average at 50 ppm with a 100 ppm short-term exposure limit (STEL). Most Boating Industries Alliance Australia member shops design for an operator breathing-zone concentration under 20 ppm to provide adequate margin for hot summer days when ventilation effectiveness drops.

The styrene capture strategy is layered. Local exhaust ventilation (LEV) at every active mould — typically a slot canopy hood at 0.5 to 1.0 m/s capture velocity drawn back through a labyrinth or activated carbon filter — handles the resin face emission during gel coat and layup. General ventilation across the mould room at 4 to 6 air changes per hour dilutes residual vapour and prevents accumulation in roof voids and overhead crane gantries. For VARIM and RTM closed-mould infusion the open resin emission collapses by 70 to 90 percent versus open mould, but the vacuum exhaust line itself becomes a concentrated styrene source and must be ducted to a carbon scrubber or biofilter, not vented to the workshop.

Material selection on the styrene exhaust ductwork is straightforward — 316L stainless 1.5 mm or polypropylene where the exhaust temperature stays under 60 C. Polyester resin attacks galvanised zinc through the action of the styrene solvent and the unsaturated polyester resin acidity. The CR catalyst (cumene hydroperoxide or MEKP) accelerates the attack. Field experience at Australian production boatbuilders shows galvanised duct on styrene exhaust failing within 12 to 18 months — pin-holes at the seams, rust streaks down the duct exterior, eventually full failure of the duct skin. 316L stainless lasts 20 to 25 years on the same duty.

Duct transport velocity on styrene exhaust is 5 to 8 m/s. Below 5 m/s styrene condenses inside the duct on cold mornings and creates a dripping liquid that finds its way back to the workshop floor. Above 10 m/s the duct pressure drop becomes excessive and the fan static pressure rises beyond the air handler's design. The 5 to 8 m/s envelope is the right balance for typical production hood geometries.

Air volume for a typical Australian production boatbuilder mould room runs 6 to 12 m3/s supply with 6 to 12 m3/s LEV extract at the active hoods. A Riviera-scale operation with 8 to 12 parallel mould bays supplies 50 to 80 m3/s total across the mould rooms. The supply train must include a make-up air conditioning load of 200 to 400 kW cooling capacity for Australian summer dehumidification (Coomera QLD summer 33 C dry-bulb and 70 percent RH) and 100 to 150 kW heating capacity for winter make-up.

SBKJ machinery for fibreglass styrene extraction ductwork: SBAL-V auto duct line in 316L stainless variant produces 1.5 mm rectangular duct for the mould room exhaust trunk and supply. SBFB-1500 spiral tubeformer produces 100 to 1,500 mm round duct for the return-air trunks and the carbon scrubber inlet. SBSF-1525 stitchwelder handles heavy-gauge sections at the scrubber connection and the carbon filter housing. Lead time 14 to 16 weeks for the 316L stainless SBAL-V configuration.

Aluminium NFPA 484 boatbuilder dust collection

Aluminium dust from grinding, sanding, polishing, plasma cutting and laser cutting is NFPA 484 Class D combustible metal with deflagration potential. Australian boatbuilders running 5083, 5086, 5052 marine plate plus 6061 and 6082 structural extrusion — Telwater Quintrex tinnies, Stessl Boats Caboolture, Stacer fishing boats, SilverYachts Henderson WA superyacht hulls, Echo Yachts catamaran trimaran, Civmec naval steel and aluminium, Aussie Boatworks Brisbane commercial, Sea Land Air NSW patrol, Hummingbird Boats Tasmania, AMI Marine Industries Coffs Harbour and Yamba Marine — all face the same compliance envelope.

The deflagration parameters drive the design. Aluminium fines under 500 microns produce Kst values of 200 to 415 bar.m/s depending on alloy and particle size — Dust Hazard Class St-2 with possibility of escalation to St-3 on very fine fines under 50 microns. Pmax (maximum explosion pressure) is 10 to 12 bar. The minimum ignition energy (MIE) is 5 to 50 mJ depending on humidity, particle size and alloy — extremely low compared to wood dust at 100 mJ or carbon dust at 200 mJ. A static discharge from an ungrounded duct is sufficient to ignite a fines deflagration.

Capture at source through localised exhaust at every grinding, sanding and polishing station at 18 to 23 m/s transport velocity per NFPA 91. Wet collector (water-bath scrubber) is the preferred technology for aluminium fines because it captures the fines in water and quenches any deflagration before it can propagate. Dry collectors (cyclonic or bag house) are acceptable with explosion suppression (chemical isolation valve and explosion vent) and explosion isolation (rotary airlock or air gap) between the upstream ductwork and the collector. NFPA 484 explicitly requires explosion isolation to prevent flame and pressure wave propagation back up the duct to ignite further fines.

Water deluge fire suppression on aluminium dust is restricted. Al plus H2O produces aluminium hydroxide (Al(OH)3) plus hydrogen gas (H2). Hydrogen evolution can convert a small fire into a deflagration. Specialist Class D extinguishing media is mandatory — Met-L-X (sodium chloride base), Pyrene G-Plus (graphite base) or Lith-X (graphite base) at every grinding station and adjacent to the dust collector. Class D extinguishers are non-conductive and absorb heat without producing reactive gas.

Ductwork specification for aluminium dust collection: galvanised 1.2 mm minimum with conductive seam sealant, or 316L stainless 1.5 mm where additional corrosion margin is required. All joints bonded and grounded to a single equipotential point at less than 10 ohms resistance — the bonding test is a discrete commissioning step before the duct is brought into service. Rotary airlock or air gap isolation between the duct and the collector. NFPA 484 explicitly prohibits sharing aluminium dust ductwork with steel or stainless dust ductwork — the mixed reactivity (aluminium plus iron oxide is a thermite combination) creates ignition risk.

Dust collection ductwork on a Quintrex-scale aluminium tinny line typically runs 8 to 15 m3/s through 10 to 20 grinding and polishing stations. A SilverYachts or Echo Yachts superyacht builder runs 30 to 80 m3/s across the assembly hall covering 20 to 50 active welding and grinding zones during peak build. Engine for the fan must be Ex e or Ex d rated per AS/NZS 60079 because the fan operates downstream of the dust collector and any breakthrough of fines past the collector reaches the fan.

SBKJ machinery for aluminium dust collection: SBFB-1500 spiral tubeformer in galvanised 1.2 mm heavy gauge produces the round dust transport ducts with conductive seam construction. SBAL-V auto duct line in galvanised or 316L stainless variant produces the rectangular plenum and ductwork at the collector inlet. SBSF-1525 stitchwelder handles the heavy-gauge collector housing and the explosion vent ducts.

Spray booth isocyanate marine topcoat

Marine topcoat application using two-component polyurethane systems (Awl-Grip, Imron, International Perfection, Hempel Hempathane, Jotun Yachting Topcoat, Pettit) generates isocyanate aerosol with TDI (toluene diisocyanate) and MDI (methylene diphenyl diisocyanate) components at a workplace exposure standard of 0.005 ppm TWA. This is twenty times more restrictive than styrene and ten times more restrictive than most automotive paint solvents. Isocyanate is a known asthmagen and skin sensitiser with chronic effects including occupational asthma and contact dermatitis. The 0.005 ppm WES is unforgiving — at this concentration the human nose cannot detect the chemical and the operator has no warning of exposure.

The marine isocyanate spray booth is classified AS/NZS 60079 Zone 1 because isocyanate aerosol combined with the solvent carrier (xylene 50 ppm WES, MEK 200 ppm, ethyl acetate 200 ppm) forms an explosive atmosphere within the booth volume during active spraying. Booth construction is fire-rated steel panel with non-sparking light fittings, spark-free electrical switchgear outside the booth envelope, and dual-redundant interlocked extract fans on emergency power. Loss of either extract fan immediately stops the operator's compressor and triggers an alarm at the booth panel.

Airflow inside the booth is downdraft at 0.4 to 0.5 m/s leaf-canopy velocity for OEM-grade superyacht work (SilverYachts, Echo Yachts, Riviera Custom Yachts division) and cross-draft at 0.5 to 0.6 m/s for production motor yacht work (Riviera production line, Maritimo, Cruise Craft, Lightwave Yachts). Same velocity envelope as automotive paint booths but with much higher booth volumes because hull lengths run 10 to 50 m. A typical marine isocyanate booth has internal volume of 200 to 2,000 m3 covering a single hull or hull section.

AS 4114.2 section 4 sets the booth construction and ventilation rules. NFPA 33 chapter 7 applies as overlay for export builds destined for the USA (Riviera and Maritimo export significant volume to the USA market). The face velocity floor in both standards is 0.5 m/s measured 100 mm above the booth floor during active spraying. Exhaust duct termination is 1.8 m above the booth roof and 6 m horizontal from any opening or property line.

Ductwork specification is 304L stainless 1.5 to 2.0 mm for the spray exhaust riser (the isocyanate aerosol and amine accelerator attack zinc within 6 to 12 months) and 316L stainless 1.5 mm for the post-cure bake oven at 50 to 60 C. Galvanised duct on marine isocyanate exhaust fails within a single production season. Field experience at Australian boatbuilders confirms — every shop that tried galvanised on isocyanate exhaust replaced it within 18 months at 3 to 5 times the original installed cost because the replacement required hull movement out of the booth.

Filter train on the booth exhaust is a three-stage assembly: dry paper or glass fibre filter at the booth wall removes the aerosol mist, a secondary HEPA pre-filter removes the residual fine droplets, and either an activated carbon adsorber or a regenerative thermal oxidiser (RTO) removes the residual solvent VOC. Marine builders running high topcoat throughput (Riviera, Maritimo) install RTO at 30 to 60 m3/s capacity. Smaller builders install carbon adsorber at 5 to 15 m3/s. The state EPA permit determines the destruction efficiency requirement (typically 95 percent).

SBKJ machinery for the isocyanate spray booth exhaust: SBAL-V auto duct line in 316L stainless variant produces 1.5 mm rectangular duct for the booth exhaust trunk. SBFB-1500 spiral produces the round exhaust riser to the abatement equipment and the stack discharge to atmosphere. SBSF-1525 stitchwelder handles the heavy-gauge bake oven duct at 60 C.

Engine dyno commissioning exhaust stack

Diesel engine commissioning is a routine step on every motor yacht, superyacht, catamaran and aluminium plate boat fabrication. Riviera Coomera, Maritimo, SilverYachts Henderson WA, Echo Yachts and the entire aluminium plate boat sector run diesel engines through a dock-side or in-shed commissioning sequence before the hull is launched. Engine types include Cummins QSB6.7, QSC8.3, QSL9, ISL11.9, QSM11 and QSK19; Caterpillar C18 and C32; MTU 8V, 12V and 16V 2000 series and 4000 series; MAN V8 and V12; Volvo Penta IPS and D-series; and Yanmar marine diesels. Outboard engines (Yamaha, Suzuki, Mercury, Honda) commission on test tanks rather than dyno.

Power range on inboard diesel runs 150 kW (twin-engine motor yacht) to 800 kW per engine (single superyacht main propulsion) with quad-engine high-performance configurations exceeding 3 MW total. Exhaust gas temperature at full load is 350 to 450 C measured at the manifold flange. Composition includes carbon monoxide (CO at workplace exposure standard 30 ppm), nitrogen dioxide (NO2 at 3 ppm STEL), respirable particulate (5 mg/m3 inhalable, 3 mg/m3 respirable), unburnt hydrocarbons and water vapour. The combined hazard requires capture and discharge above the building roof — no recirculation, no fan motor in the exhaust stream without explosion-proof rating.

Exhaust stack design: 316L stainless 1.5 to 3.0 mm gauge depending on diameter. Thermal expansion at 450 C through-bore is 7 mm per metre versus ambient — a 10 m stack grows 70 mm linearly during a full-power run, and bellows-style expansion joints at each wall penetration and each change of direction are mandatory. Stack diameter sized for 8 to 12 m/s velocity at rated engine power. Stack height extends 2 to 3 m above the building roof to clear the building envelope and the operator-occupied platforms. Internal cleanout access every 4 m of run with bolt-on cover and high-temperature gasket.

Building height for engine commissioning sheds is 8 to 10 m to allow the stack to clear the building envelope before any operator-occupied platform or office. Smaller boatbuilders sharing an open-bay shed configure a moveable stack on a wheeled gantry that connects to the engine exhaust via a high-temperature flexible coupling and discharges through a roof penetration with a gate damper that closes when the stack is moved.

Make-up air for the engine commissioning bay is 2 to 4 m3/s at ambient or filtered outdoor air, sufficient to dilute any CO leakage from the exhaust train back to the operator's breathing zone. CO monitors with audible and visual alarms at 20 ppm warning and 30 ppm action thresholds are mandatory at every commissioning station.

For superyacht builders running multi-MW engine commissioning (SilverYachts Silver Cloud at 4 to 8 MW total propulsion, Echo Yachts White Rabbit at 6 to 10 MW), the engine commissioning hall is a dedicated assembly with multiple stack discharges and a dedicated CO ventilation interlock that shuts down engine operation if exhaust capture fails at any point. The stack ductwork on a superyacht commissioning hall reaches 200 to 500 m total length and is the single largest 316L stainless installation in the building.

SBKJ machinery for engine dyno exhaust: SBAL-V auto duct line in 316L stainless variant produces the rectangular plenum sections at the engine exhaust manifold capture hood. SBFB-1500 spiral tubeformer produces the round vertical stack section from 200 to 1,500 mm diameter. SBSF-1525 stitchwelder handles the heavy-gauge sections at the stack base and any high-pressure runs.

Riviera Coomera HVAC and the Coomera marine precinct

Riviera Australia at Coomera operates the largest single-site motor yacht production facility in Australia and one of the largest in the southern hemisphere. The Coomera campus covers approximately 16 hectares with multi-bay parallel production for the 39 ft to 72 ft luxury motor yacht range. Annual production has consistently exceeded 100 hulls with export delivery to the USA, EU, Asia Pacific and the Middle East. Riviera's HVAC load is the benchmark for production motor yacht builders globally.

The Riviera production process runs eight sequential stages, each with distinct ventilation signature. Mould preparation (gel coat application, release agent, surface prep) at 6 to 8 m3/s LEV extract. Fibreglass hand layup and VARIM at 12 to 18 m3/s LEV extract across parallel hulls. Hull demoulding and transfer to fit-out bay at 4 to 6 m3/s general dilution. Interior joinery and timber fit-out at 4 to 6 m3/s plus localised dust extraction. Mechanical fit-out (Cummins, MAN, Caterpillar engine install, electrical, plumbing, HVAC, watermaker, generator) at 4 to 8 m3/s general dilution. Isocyanate topcoat application at 6 to 12 m3/s exhaust per booth station with three to six booths operating in parallel during peak. Post-cure bake at 50 to 60 C and 1 to 3 m3/s per booth. Sea trial preparation including engine commissioning at 2 to 4 m3/s plus stack discharge.

Total Riviera Coomera installed HVAC supply runs 40 to 70 m3/s across the campus with isocyanate spray exhaust dominating the extract load at 30 to 60 m3/s through an RTO abatement system. Ductwork stock on site exceeds 8 to 12 km of supply (galvanised) plus 4 to 6 km of extract (316L stainless on isocyanate, polypropylene on styrene), plus 2 to 3 km of round dust collection (galvanised). The duct fabrication challenge on a Riviera-scale operation is sustained at 200 to 400 m per day during peak fit-out periods.

Maritimo at Hope Island and Coomera runs a similar process at smaller scale — 30 to 60 hulls per year of 50 to 75 ft luxury motor yacht. Total installed HVAC is 20 to 40 m3/s. The Coomera marine precinct as a whole — Riviera, Maritimo, Quintrex, Stacer (Telwater BRP), Cruise Craft, Lightwave Yachts, Haines Hunter at Caloundra, Riviera Custom Yachts, The Boat Works refit yard, Riviera Service Centre, plus the Sanctuary Cove marina and refit facilities — installs cumulative HVAC capacity of 200 to 400 m3/s, making it one of the largest concentrations of marine HVAC infrastructure in the world.

Sanctuary Cove International Boat Show is held at the precinct each May and brings the global marine industry through the Coomera builders for new model launches and dealer visits. The boat show drives a seasonal pulse in production schedules — every builder targets a launch hull or new model for the May show, and the HVAC system must deliver continuous compliance through the peak production weeks of February to April.

Superyacht Henderson WA Echo Yachts and SilverYachts

The Henderson Maritime Precinct in Perth WA hosts the largest superyacht and naval shipbuilding cluster in Australia. The cluster's three flagship builders — SilverYachts, Echo Yachts and Civmec — drive a different HVAC scale than the Coomera production motor yacht cluster. Henderson sheds are vast (typical scale 100 m by 50 m by 25 m high), build cycles run 12 to 36 months per hull, and the cumulative ventilation load reaches 100 to 200 m3/s installed for a full superyacht builder.

SilverYachts at Henderson WA builds Silver Cloud at 134 m and other Silver-series superyachts up to 90 m — among the largest Australian-built private and commercial vessels. The build process runs aluminium-dominated with steel framework on the larger commercial hulls. CNC plasma, water jet and laser cutting on 5083 and 5086 marine plate. Pulse MIG and TIG welding with extracted welding fume capture at every active welding station. Aluminium grinding and polishing dust collection at 18 to 23 m/s transport velocity through wet collector. Topcoat application in a dedicated mobile spray tent enclosure inside the assembly hall — the tent is configured as a temporary AS/NZS 60079 Zone 1 enclosure for each topcoat campaign. Engine commissioning on multi-MW diesel propulsion with stack discharge through the assembly hall roof.

Echo Yachts at Henderson WA built White Rabbit at 84 m — the largest aluminium catamaran-trimaran superyacht in the world. The Echo Yachts process runs similar to SilverYachts but with the catamaran-trimaran geometry driving multiple parallel hull assembly. Composite prepreg and autoclave cure for selected superstructure sections, with autoclave ventilation at 80 to 120 C and 2 to 4 bar absolute pressure. Aluminium dust collection scaled to 30 to 80 m3/s during peak grinding activity across the parallel hulls.

Civmec at Henderson WA builds Hunter-class frigates for the Royal Australian Navy under the Hunter Class Frigate Program. Civmec's work overlaps with the recreational superyacht sector through shared aluminium and steel fabrication capability, shared dust collection infrastructure and shared topcoat booth design. The Hunter-class program adds steel hull construction at scale (a frigate hull is approximately 8,800 tonnes versus 200 to 1,000 tonnes on a superyacht), with associated welding fume capture, steel grit blast booth ventilation and full marine corrosion protection paint application.

Henderson WA sheds operate in a coastal chloride atmosphere that demands 316L stainless on all marine generator room, battery room, isocyanate spray booth and external ductwork. Galvanised duct in coastal Henderson lasts 5 to 8 years; 316L stainless lasts 25 to 30 years. The capital cost premium on stainless is 2.5 to 3.5 times galvanised but lifecycle cost is lower for the long build cycles typical of superyacht and naval work.

SBKJ machinery for Henderson WA superyacht scale: SBAL-V at 316L stainless 1.5 mm produces the bulk rectangular ductwork. SBFB-1500 spiral handles round dust collection and engine stack. SBSF-1525 stitchwelder handles the heavy-gauge fire-rated sections around the topcoat enclosure. For Civmec-scale heavy industrial steel hull work, SBSF-1525 plus the higher-tonnage variants of the SBKJ heavy-gauge line cover the bake-out and grit-blast booth ductwork.

Trailer boat and aluminium tinny manufacturing — Telwater Quintrex, Stessl, Stacer

Australian aluminium trailer boat manufacturing is dominated by Telwater (BRP subsidiary) operating Quintrex, Stessl and Stacer brands. Telwater's Coomera facility produces aluminium tinnies and plate boats from 3 to 7 m at high volume — typical annual production runs into the thousands across the three brands. Stessl Boats at Caboolture QLD (acquired by Hyundai Marine) operates a parallel production line. Cruise Craft at Coomera operates aluminium plate boats at the luxury trailer boat end of the market.

The aluminium trailer boat process is more standardised and higher-volume than the fibreglass motor yacht process. CNC blanking on 5083 and 5052 marine plate (typically 3 to 6 mm gauge for tinnies, 4 to 8 mm for plate boats). Press brake forming on the hull side panels and transom. Pulse MIG welding on the longitudinal seams with extracted welding fume capture at every welding station. TIG welding on the visible cosmetic seams and the structural frames. Aluminium dust extraction at 18 to 23 m/s transport velocity from grinding and polishing stations. Anodising or anti-fouling paint application below waterline on plate boat models. Final fitout with Yamaha, Suzuki, Mercury or Honda outboard engines (no in-shed dyno commissioning required — outboards run on test tanks).

HVAC load on a Telwater-scale aluminium tinny line runs 10 to 25 m3/s installed. The dust collection load dominates at 8 to 15 m3/s through wet collector. Welding fume capture at 2 to 6 m3/s across 10 to 20 active welding stations. Anti-fouling and topcoat paint booth at 2 to 4 m3/s per booth station for production work (cross-draft booth at 0.5 m/s face velocity).

Ductwork specification on aluminium tinny manufacturing: galvanised 1.2 mm with conductive seam sealant for the aluminium dust collection (NFPA 484 compliance). 316L stainless 1.5 mm on the anti-fouling paint exhaust (copper-based biocide attacks galvanised zinc). 316L stainless on the welding fume capture (ozone and Cr from filler metal attack galvanised). Galvanised 0.8 to 1.2 mm on general workshop supply. SBKJ machinery: SBFB-1500 spiral for dust collection and welding fume capture, SBAL-V at GAL or 316L for supply and paint exhaust depending on the run.

Smaller aluminium boatbuilders (AMI Marine Industries Coffs Harbour, Sea Land Air NSW, Hummingbird Boats Tasmania, Aussie Boatworks Brisbane) run similar process at smaller scale. Total HVAC load is 5 to 15 m3/s installed across the smaller shops, with the dust collection load proportionally smaller.

Catamaran and sailing yacht — Lightwave, Schionning, Beneteau, Fountaine Pajot

Catamaran and sailing yacht production runs a slightly different ventilation envelope from production motor yacht. The catamaran geometry drives twin hull parallel assembly, the sailing yacht typically uses heavier composite construction with epoxy and high-modulus glass or carbon fibre, and the topcoat application is often less aggressive than motor yacht (less isocyanate, more single-pack alkyd or two-pack epoxy).

Lightwave Yachts at Coomera builds Australian-designed catamarans in the 38 to 50 ft range, with composite construction running fibreglass hand layup and VARIM. HVAC load is 15 to 25 m3/s installed across the build campus. Schionning Designs at NSW supplies catamaran kits and plywood-epoxy designs for owner-builders and small commercial builders — the Schionning epoxy and timber dust extraction load is smaller (5 to 10 m3/s) but the resin store and epoxy mix room demands AS 1940 flammable liquid handling.

Sailing yacht importers (Beneteau Australia, Jeanneau Australia, Fountaine Pajot Australia, Catana Australia) operate commissioning yards rather than full build, but the commissioning includes engine fit-out (Yanmar or Volvo Penta inboard), rig installation, electronics fit-out and pre-delivery topcoat touch-up. HVAC load is smaller (5 to 12 m3/s installed) but the rig and engine commissioning ventilation envelope is unchanged from the full-build operations.

Whitsundays Sailing and Charter operations in QLD provide a significant refit and operational base for sailing catamaran and monohull. The refit work overlaps with the heritage Norman R. Wright and Sons at Bulimba QLD, and with Riviera Yamba in NSW. Refit yards run lower HVAC load than new build (3 to 10 m3/s installed) but with high variability — peak loads during a single major refit can exceed the steady-state install for a small new-build yard.

Marine refit yards — Rivergate, Yamba, The Boat Works, Norman R. Wright

Marine refit and warranty repair operates as a distinct sector from new-build with a different HVAC envelope. The refit yard handles multiple vessel sizes simultaneously (from a 4 m tinny through to a 50 m superyacht), with a different process mix on each vessel (full topcoat refresh, engine overhaul, hull blasting, anti-fouling reapplication, joinery refurbishment, electronics upgrade). Refit yards are typically open-bay sheds with mobile extraction equipment rather than the fixed LEV infrastructure of a production builder.

Rivergate Marina and Shipyard at Murarrie Brisbane is one of Australia's largest marine refit yards, supporting commercial and recreational vessels up to 80 m. The yard operates multiple parallel bays with mobile spray tents for topcoat work, mobile dust extraction for hull blast and grinding, and a dedicated engine overhaul shop with stack discharge for diesel dyno work. Total installed HVAC reaches 30 to 60 m3/s with high variability depending on active jobs.

Yamba Marine at NSW handles refit and small build with a similar mobile equipment philosophy. Norman R. Wright and Sons at Bulimba QLD is a heritage timber and composite yard focused on restoration and bespoke commercial vessel work — the timber dust extraction and varnish application ventilation is the dominant load (5 to 10 m3/s). Riviera Service Centre at Coomera and Gold Coast handles warranty work on Riviera production hulls with a shed-scale operation parallel to the main production facility. Sanctuary Cove Marina Refit operates as a marina-integrated refit facility for visiting superyachts and motor yachts. The Boat Works at Coomera is a multi-tenant refit precinct with parallel small businesses operating in shared sheds.

Refit yard HVAC differs from new-build in three ways. First, the ventilation must be reconfigurable — mobile extraction with quick-connect ductwork allows the system to follow the vessel to whichever bay it occupies. Second, the standards apply per AHJ — refit work must satisfy AS 4114.2 for any topcoat application even though the work may be performed inside a temporary spray tent rather than a fixed booth. Third, the marine corrosion environment is at its most severe — coastal salt-spray plus organic loading from active marina water demands 316L stainless on all permanent ductwork plus regular replacement of mobile components.

Marine generator and battery room ventilation

Every modern motor yacht, superyacht, catamaran and aluminium plate boat over 8 m hull length carries a marine generator (Cummins Onan, Northern Lights, Kohler, Mase, Westerbeke or Fischer Panda) plus a substantial battery bank (AGM, gel, lithium-ion LiFePO4 or VRLA). The build-side ventilation of the generator and battery compartments during commissioning differs from the on-vessel ventilation specified by ISO 12215 or NSCV — but the build-side problem still requires capture and discharge.

Marine generator commissioning generates the same CO, NO2 and particulate emission profile as the main engine dyno commissioning at smaller scale (typically 5 to 50 kW versus 150 to 800 kW). The on-vessel generator exhaust pipe connects to a dock-side flexible coupling and discharges through the same building stack that handles the main engine. CO monitors at the commissioning bay maintain operator safety.

Marine battery commissioning is more subtle. Lithium-ion LiFePO4 battery commissioning generates negligible gas emission and requires only general dilution ventilation. AGM and gel battery commissioning generates trace H2 evolution during initial bulk charge — sufficient to trigger AS/NZS 60079 Zone 2 classification within the battery compartment but typically not Zone 2 in the building airspace. VRLA (valve-regulated lead-acid) battery commissioning can release significant H2 during a fault condition, demanding Zone 2 classification at the build-side and a dedicated extract fan on emergency power.

Ductwork on marine generator and battery room ventilation: 316L stainless 1.5 mm because chloride-laden marine atmosphere reaches the room interior even in the build shed. Service life on 316L is 25 to 30 years versus 5 to 8 years on galvanised. SBKJ SBAL-V at 316L is the standard output.

Marine fit-out joinery and timber dust

Custom interior joinery is the single most distinguishing feature of an Australian production motor yacht. Riviera, Maritimo and the superyacht builders run dedicated joinery shops with high-end timber (teak, cherry, walnut, oak, blackwood), veneer overlays on plywood substrate, Formica and Corian solid surface, leather upholstery and high-pressure laminate. The joinery shop ventilation is dominated by timber dust extraction at every sanding, routing and edge-banding station, plus contact cement and adhesive solvent capture (toluene 50 ppm WES, MEK 200 ppm) at every gluing operation.

Timber dust extraction runs at 18 to 23 m/s transport velocity per NFPA 91 through cyclonic pre-separator and bag house filter. Wood dust is combustible (Kst 100 to 200 bar.m/s, lower than aluminium but still deflagration-capable) and the dust collection system requires explosion suppression and isolation in larger installations. AS 3957 dust hazard area classification applies. NFPA 664 (consolidated into NFPA 660 in 2025) covers wood and other combustible dust handling.

Contact cement and adhesive solvent capture runs through localised exhaust at each gluing station at 0.5 to 1.0 m/s capture velocity. Ductwork 316L stainless because solvent attack on galvanised is significant over the joinery shop's operational life. Air supply at 4 to 6 ACH plus the dust collection and adhesive solvent extract.

Total joinery shop HVAC on a Riviera-scale operation runs 8 to 15 m3/s installed. Smaller builders run 3 to 8 m3/s. The joinery shop typically sits adjacent to the fit-out bay so the finished cabinetry can move directly into the hull.

Composite autoclave and prepreg processing

Composite prepreg processing — carbon fibre reinforced polymer (CFRP), glass-reinforced polymer (GRP) and Kevlar aramid laminates — runs at the high-performance end of marine manufacturing. Australian builders running prepreg autoclave include Echo Yachts (selected superstructure on White Rabbit catamaran-trimaran), some Beneteau composite work in commissioning, race yacht and high-end catamaran one-offs, and selected naval and patrol craft for Civmec and Sea Land Air. Production motor yacht (Riviera, Maritimo, Whittley, Haines) does not typically use autoclave-cured prepreg.

The autoclave is a pressure vessel cured at 80 to 120 C and 2 to 4 bar absolute pressure under nitrogen blanket. The autoclave itself is registered as a pressure vessel to AS 1210 (or equivalent) but the surrounding ventilation handles the off-gassing during ramp-up and post-cure cool-down. Resin solvent (epoxy thinner, IPA, acetone, MEK) flashes during ramp-up at 60 to 80 C, generating peak VOC concentrations that must be diluted to under 25 percent of the lower explosive limit.

Prepreg layup room cleanliness targets ISO 8 ambient or unclassified clean at 22 C plus or minus 2 and 50 percent plus or minus 10 RH — tighter than a workshop but looser than a pharma cleanroom. The prepreg material itself is stored at minus 18 C in a dedicated freezer and brought to ambient before layup; the freezer ventilation must avoid condensation on the prepreg material as it warms.

Vacuum bag debulk station extracts at 0.5 to 1.0 m3/s per active mould through HEPA pre-filter. The vacuum exhaust line carries concentrated resin solvent and must be ducted to a carbon scrubber. Cured composite sanding, drilling and machining generates respirable fibre dust (carbon fibre, glass fibre, Kevlar) at 5 mg/m3 WES inhalable, captured through localised dust extraction at each machining station.

Ductwork on composite autoclave ventilation: 316L stainless 1.5 mm because nitrogen purge and elevated cure temperature exceed polypropylene service limits. SBKJ SBAL-V at 316L plus SBFB-1500 spiral are the standard outputs.

Marine paint, anti-fouling and topside

Marine paint application runs through two distinct chemistries. Topside paint (above waterline) is two-component polyurethane (Awl-Grip, Imron, International Perfection, Hempel, Jotun, Pettit) with isocyanate aerosol at 0.005 ppm WES as covered in the spray booth section above. Anti-fouling paint (below waterline) is a hydrolytic copper-based or biocide-based coating that releases biocide slowly into the surrounding water to prevent marine growth attachment.

Anti-fouling application uses cuprous oxide as the primary biocide (TBT was banned globally in 2008 by IMO resolution) plus a hydrolytic binder system. The application is typically brush, roller or low-pressure spray rather than the high-velocity atomisation used on topside. The ventilation envelope is less aggressive than isocyanate topside — capture velocity 0.3 to 0.5 m/s at the hull face, exhaust velocity 5 to 8 m/s in the duct. But the copper biocide attacks galvanised zinc through galvanic action, demanding 316L stainless on the anti-fouling exhaust duct.

Topside paint application includes primer, base coat, clearcoat and metallic effect on premium motor yacht builds. Riviera's Premium and Custom Yacht ranges apply 4 to 6 coats of topside on the hull plus interior cabinetry varnish in a separate booth. Total paint application time per hull on a 60 ft motor yacht runs 80 to 150 hours including masking, application and post-cure. The spray booth must accommodate this duration with continuous airflow and consistent humidity control to avoid solvent flash issues.

Storage, warehouse and shipping ventilation

Production motor yacht and aluminium plate boat manufacturing carries a significant storage and shipping load. Riviera, Maritimo, Telwater Quintrex and the larger builders operate dedicated warehouse buildings for raw material (aluminium plate, fibreglass roving, resin drums, paint, hardware), parts (engines awaiting installation, generators, electronics, joinery materials) and finished hulls awaiting export. Export crating, container loading (20 ft, 40 ft and 40 ft Open Top) and oversized dimension transport (rail, truck, ocean) all happen on site.

Warehouse ventilation runs at 1 to 2 ACH general dilution for storage buildings with no active process. Resin store and paint store buildings require dedicated AS 1940 compliant flammable liquid storage with bunding, separation, fire-resistant construction and forced ventilation at 6 to 12 ACH continuous. The forced ventilation prevents accumulation of solvent vapour above the LEL during the warm summer months.

Shipping bay ventilation accommodates LPG-powered forklift charging (Zone 2 around the charging area), diesel-powered crane operation (CO monitoring), and battery-electric reach truck charging (general dilution for the rapid charge banks). Total shipping bay HVAC load is 1 to 3 m3/s installed.

Administration, showroom and CAD room

Every Australian production boatbuilder operates an administration, sales and engineering function on the same campus as the build shed. Riviera Coomera, Maritimo, Telwater, SilverYachts and the larger superyacht builders all have substantial office, CAD/engineering and showroom components.

Office ventilation runs to AS 1668.2 commercial standards at 10 L/s per person outdoor air, NC-35 acoustic envelope per AS/NZS 2107, 22 to 24 C and 50 plus or minus 10 RH. Engineering and CAD rooms require lower noise (NC-30) and tighter temperature control (22 plus or minus 1) to support precision CAD and ESD-sensitive electronics.

Showroom ventilation is the prestige zone. Riviera's Coomera showroom hosts dealer visits, customer specification meetings and Sanctuary Cove Boat Show preview events. The showroom must accommodate full motor yacht display (60 to 70 ft hulls under cover) with controlled lighting, temperature and humidity. Total showroom HVAC load is 5 to 12 m3/s depending on showroom size.

Administration HVAC is typically conventional VAV (variable air volume) system with central air handler, ducted supply to office zones, return-air ceiling plenum and packaged or chiller-based cooling. Galvanised 0.8 to 1.0 mm rectangular duct on the SBAL-V at standard configuration is the dominant output.

Acoustic and NC requirement across boatbuilder zones

The acoustic envelope across an Australian boatbuilder facility varies from NC-30 in the CAD room and engineering office through NC-35 in the administration and showroom, NC-45 in the workshop and fit-out bay, to NC-50 in the dust collection plant room and engine commissioning bay. AS/NZS 2107 sets the noise criterion ranges for different occupancy types.

Duct-borne noise is the primary acoustic challenge in HVAC design. Large supply fans on the mould room ventilation (50 to 100 kW each) generate fan noise that propagates through the supply duct to every grille. Sound attenuators (lined splitter silencers) at the supply trunk reduce duct-borne noise by 15 to 25 dB across the octave band. Acoustic lining on the duct interior provides additional 5 to 10 dB attenuation but introduces fibre release concerns in any food-grade or healthcare context (not relevant for marine but relevant for adjacent industries).

SBKJ machinery for acoustic and silencer fabrication: SBLR-600 louvre and register former handles the silencer end caps and acoustic louvre. SBAL-V at standard configuration produces the silencer outer casing.

Hazardous area density and AS/NZS 60079 compliance

Marine boatbuilders carry the highest density of AS/NZS 60079 hazardous areas of any industrial occupancy. A typical Riviera-scale operation has four to seven distinct Zone 1 or Zone 2 areas plus three to six Zone 22 dust areas. Every duct penetration through a hazardous area requires either certified flame arrestor, certified seal, or dedicated isolation per the zone classification.

The compliance methodology runs through a single integrated drawing — the hazardous area drawing per AS/NZS 60079.10.1 — that marks every Zone on the site plan with the applicable distance, height, ventilation rate and equipment certification level. The drawing is the master reference for the entire ventilation design. Any change in process (a new resin chemistry, a different spray paint, a new battery bank) triggers a hazardous area drawing revision.

The boatbuilder's process safety case relies on the hazardous area drawing being correct. State WorkSafe regulators (WorkSafe VIC, SafeWork NSW, Workplace Health and Safety QLD, WorkSafe WA, SafeWork SA, WorkSafe TAS) audit the hazardous area drawing against the actual installation during routine and incident-triggered inspections. A mismatch between the drawing and the installation is the most common finding in marine boatbuilder process safety audits.

Marine corrosion environment and chloride attack

Coastal sheds at Coomera, Henderson, Brisbane, Yamba, Caboolture, Caloundra and Lara sit in chloride-laden marine atmosphere with airborne chloride deposition of 50 to 500 mg/m2/day depending on distance from the coast and prevailing wind direction. The chloride attack on galvanised zinc is significant — typical galvanised duct service life in a coastal Henderson WA or Coomera shed is 5 to 8 years versus 20+ years inland.

Material selection accommodates the marine corrosion environment in three ways. First, switching to 316L stainless on any duct that runs externally or near the shed exterior — service life extends to 25 to 30 years on stainless. Second, applying heavy-zinc coating (Z450 instead of standard Z275) on galvanised duct that must run interior — service life extends to 12 to 15 years on the heavier zinc coating. Third, applying epoxy-zinc primer plus polyurethane topcoat on exposed galvanised duct — service life extends to 10 to 12 years but with finite repaint cycle every 5 to 7 years.

The cost premium on 316L stainless versus galvanised at marine sheds is 2.5 to 3.5 times the installed cost per metre. The lifecycle cost (capital plus replacement plus repaint plus disruption) typically favours 316L on any duct that handles process exhaust or runs externally, and favours galvanised on any interior supply duct in a non-corrosive zone. The boundary between the two material choices runs through every boatbuilder design and is the most contested decision in the marine HVAC design review.

NCC, structural and seismic compliance

Marine boatbuilder sheds are typically National Construction Code (NCC) Class 8 industrial occupancy with Class 7b storage component and Class 9b assembly component on the showroom side. Fire resistance ratings (FRL) range from 60/60/60 on internal partitions through 120/120/120 on bake-out rooms and resin stores. AS 1530.4 fire resistance testing applies to penetrations and seal systems.

Structural compliance runs through AS/NZS 1170 series. Part 2 covers wind load (boatbuilder sheds at Coomera face significant cyclone exposure per Region B wind zone), part 4 covers earthquake load, part 5 covers marine load (relevant for shed structure, not vessel). AS 1100.501 plus ISO drawing standards cover the duct and ventilation drawing standards.

Electrical compliance runs through AS/NZS 3000 wiring rules plus AS/NZS 3760 portable electrical and RCD residual current device protection. AIRAH DA series application guides cover HVAC-specific best practice within the Australian regulatory framework.

SBKJ machinery for marine boatbuilder projects

SBKJ duct fabrication machinery covers the full range of marine boatbuilder requirements, from refit yard mobile duct fabrication through to superyacht-scale 316L stainless installations. Five SBKJ machine families are sized and configured for marine boatbuilder applications.

SBAL-V auto duct line for galvanised general HVAC supply. Our flagship rectangular duct line, configured for boatbuilder projects with G90 (Z275) galvanised coil 0.8 to 1.2 mm gauge. Cuts, notches, folds, seams and TDF flanges in a single integrated pass at 8 to 15 m/min line speed depending on duct size. SMACNA, AS/NZS 4254 and EN 1505 pressure-class compliant. Single-shift output 600 to 900 m of duct per shift on typical boatbuilder duct sizes (300 to 1,200 mm). SBAL-V auto duct line specification.

SBAL-V stainless variant for fibreglass, isocyanate and engine stack. A reinforced-roll variant of the SBAL-V optimised for 316L stainless coil at 1.5 mm gauge. Stainless-specific tooling (TDF flange dies hardened for stainless work-hardening), upgraded forming pressure to handle stainless yield strength, and corrosion-resistant guideways. Single-shift output 400 to 600 m on stainless duct, lower than the galvanised variant because of slower forming speeds. The standard machine for fibreglass styrene exhaust, isocyanate spray booth exhaust, marine generator room ventilation and engine dyno exhaust stack ductwork.

SBAL-III three-line variant. A reduced-footprint variant of the SBAL-V for smaller boatbuilder operations. Suitable for builders running fewer than 20 hulls per year and where the duct fabrication is a secondary activity rather than primary scope. SBAL-V vs SBAL-III comparison.

SBFB-1500 spiral tubeformer for round duct. Round-duct fabrication for dust collection, return-air trunks, engine dyno exhaust stack and connection to the abatement system. 100 to 1,500 mm diameter range covers everything from joinery shop dust collection through to superyacht engine stack discharge. Spiral seam construction reduces leakage to under 1 percent at 1,000 Pa for SMACNA leakage class 6 — important for styrene-laden and isocyanate-laden exhaust where any leakage emits regulated VOC and operator-exposure substances. SBFB-1500 spiral tubeformer specification.

SBSF-1525 stitchwelder and SB-ZF1500 stitchwelder. For heavy-gauge fire-rated and bake-out duct fabrication. SBSF-1525 handles 1.2 to 2.0 mm galvanised or stainless with continuous seam welding at 250 C smoke spill rating per AS 1530.4. SB-ZF1500 covers a similar envelope at slightly reduced size and capital cost. Both machines used on the heavy-gauge sections at the autoclave skin, post-cure bake oven and engine dyno exhaust stack base.

SBPC1500 plasma cutter. CNC plasma cutting for transition pieces, custom fittings and non-standard duct shapes that fall outside the SBAL-V or SBFB-1500 standard output. SBPC1500 supports galvanised, stainless and aluminium coil at gauges up to 3 mm.

SBLR-600 louvre and register former. Acoustic silencer end-caps, decorative louvres on the showroom side and weather-louvre on external air intakes. Particularly useful for the showroom and administration ventilation where aesthetic finish matters.

SBTF-1500, SBTF-1602 and SBTF-2020 spiral tubeformer variants. Reduced-scope spiral variants for smaller boatbuilder operations or for refit yards needing portable spiral capability. Diameter range 100 to 1,500 mm (SBTF-1500), 100 to 1,600 mm (SBTF-1602) and 100 to 2,000 mm (SBTF-2020).

Lead time on SBAL-V galvanised configuration is 12 to 14 weeks from purchase order to factory acceptance test. Stainless variant adds 2 weeks (14 to 16 weeks total). SBFB-1500 spiral tubeformer is 10 to 12 weeks. SBSF-1525 stitchwelder is 12 to 14 weeks. SBPC1500 plasma cutter is 8 to 10 weeks. Add 4 to 6 weeks ocean freight to Australian ports and 1 to 2 weeks for installation, mechanical commissioning and operator training by SBKJ engineers on site.

Australian standards stack summary

The complete Australian standards stack for marine boatbuilder ventilation runs across fifteen primary references. AS 4114.2 governs spray booth construction and ventilation. AS 1668.2 governs general mechanical ventilation. AS 4254 covers rigid duct construction. AS 1530.3 and AS 1530.4 cover fire ignitability and fire resistance. AS 1851 covers routine fire system maintenance. AS/NZS 60079 series covers explosive gas atmosphere zone classification. AS 1940 covers flammable and combustible liquid handling. AS 3957 covers dust hazard area classification. AS/NZS 1554.1 covers carbon steel welding and AS/NZS 1554.6 covers stainless welding. AS 1665 covers aluminium welding. AS/NZS 1170 series covers structural loading (wind, earthquake, marine). AS 1100.501 covers drawing standard. AS/NZS 3000 covers electrical wiring. AS/NZS 3760 covers portable electrical and RCD. AS/NZS 2107 covers acoustic NC criteria. AIRAH DA series provides application-specific guidance.

The international standards stack adds NFPA 484 (combustible metals, particularly aluminium boatbuilders), NFPA 660 (consolidated combustible dust in 2025), NFPA 86 (ovens including post-cure bake and autoclave), ISO 12215 (small craft hull construction), CE Recreational Craft Directive 2013/53/EU (export to EU), ABYC and USCG CFR 33/46 (export to USA).

The Australian regulatory umbrella runs through AMSA (Australian Maritime Safety Authority), NSCV (National Standard for Commercial Vessels), ABP (Australian Builders Plate for recreational craft under 6 m), the Boating Industries Alliance Australia (BIAA) as the peak industry body with state affiliates Boating Industry Association (BIA NSW, VIC, SA, WA, TAS) and Marine Queensland (MQ), AIMEX (Australian International Marine Export Group), Yachting Australia, the Australian Sailing Federation and the Marine Stewardship Council (MSC).

Workplace exposure standards and WES summary

The SafeWork Australia Workplace Exposure Standards (WES) determine the design target for every LEV system in a marine boatbuilder. The relevant chemicals across boatbuilder process zones:

• Aluminium metal and oxide: 1 mg/m3 inhalable, 0.5 mg/m3 respirable. Aluminium fines combustible per NFPA 484 with water reactivity (Al + H2O = Al(OH)3 + H2).
• Stainless steel weld fume: Cr VI 0.05 STEL, Ni inhalable 1 mg/m3, Ni insoluble 0.1 mg/m3 respirable. Relevant for stainless rig and winch hardware fabrication.
• Styrene: 50 ppm TWA, 100 ppm STEL. The killer chemical of fibreglass polyester and vinylester resin.
• Epoxy resin: Skin sensitiser, allergic contact dermatitis, carpal tunnel syndrome. Used in Mas Epoxy, West System, SP Systems, Sika, Resoltech.
• Polyurethane TDI and MDI isocyanate: 0.005 ppm STEL. The killer of marine topcoat - endocrine disruption and occupational asthma.
• Solvent VOC: Epoxy thinner, acetone 250 ppm, IPA 400 ppm, MEK 200 ppm, ethyl acetate 200 ppm, toluene 50 ppm, xylene 50 ppm. Resin solvent, gel coat thinner, cleaning solvent.
• Formaldehyde: 1 ppm STEL. From phenolic and PRF marine plywood and composite resin.
• Respirable carbon fibre, glass fibre and aramid Kevlar dust: 5 mg/m3 inhalable. Cured composite sanding, drilling, machining.
• Methylene chloride (DCM): 50 ppm STEL. Paint stripper - banned in many jurisdictions in 2023, with benzyl alcohol replacement.
• Petrol and diesel benzene: 1 ppm STEL. Fuel tank fitment, bunker filling.
• Carbon monoxide (CO): 30 ppm TWA. Engine commissioning, sea trial, generator, forklift.
• CO2 and methane: CO2 5,000 ppm, CH4 1.25 percent LEL. LPG forklift, propane heater.
• Manganese respirable: 0.2 mg/m3. Welding and grinder operator exposure.
• Iron oxide: 5 mg/m3. Steel weld fume.
• Copper: 0.2 mg/m3. Bronze rigging and winch (phasing out of marine application).

Every LEV system in a marine boatbuilder must be designed to maintain operator breathing-zone exposure under the relevant WES with adequate margin. Most BIAA member shops target operating concentration under 50 percent of the WES to allow for the temperature and humidity variability in non-conditioned workshop air.

Lead times, freight and SBKJ Australia support

Lead times on SBKJ machinery for an Australian boatbuilder fit-out run 12 to 16 weeks from purchase order to factory acceptance test, plus 4 to 6 weeks ocean freight to Brisbane, Sydney, Melbourne, Adelaide, Fremantle or Hobart, plus 1 to 2 weeks installation and commissioning by SBKJ engineers on site. Total lead time from PO to operational machine is 17 to 24 weeks.

SBKJ Australia operates from Box Hill North VIC with engineering support, spare parts inventory and field service capability across the country. The Box Hill North office handles Riviera Coomera projects (truck and rail to Gold Coast), Maritimo projects (same route), Telwater projects (same route), Henderson WA superyacht builders (sea or rail to Fremantle), NSW and Tasmania builders (sea or rail), and the Brisbane and South-East Queensland refit yard cluster.

SBKJ is exhibiting at ARBS 2026 at the International Convention Centre Sydney in May 2026 (Australian Refrigeration, Building Services and Air Conditioning Exhibition) with the SBAL-V auto duct line, SBFB-1500 spiral tubeformer and SBSF-1525 stitchwelder on the stand. ARBS is the largest HVAC trade exhibition in the southern hemisphere and the primary venue for the Australian marine HVAC supply chain meeting in person. Visit the SBKJ stand at ARBS 2026 to scope a boatbuilder fit-out with the engineering team.

Cross-sector applications

Many of the engineering principles in marine boatbuilder HVAC translate to adjacent sectors. The duct fabrication machinery is the same — the tolerance, materials, pressure class and hazardous area zone change at the boundary. Five adjacent guides cover applications where SBKJ has comparable references:

• Composite manufacturing HVAC duct guide — autoclave ventilation, prepreg layup rooms and resin infusion exhaust capture for aerospace, marine and wind turbine composite manufacturing.
• Automotive paint booth HVAC duct guide — downdraft booth velocity, NFPA 33 compliance, VOC capture and RTO abatement for automotive paint shops.
• Marine offshore HVAC duct guide — offshore platform, FPSO and naval surface combatant ventilation for the offshore oil and gas and defence sectors.
• Defence and military HVAC duct guide — Civmec Hunter-class frigate, ASC submarine, BAE Systems Henderson WA and the broader defence manufacturing sector.
• Aquaculture and seafood HVAC duct guide — adjacent coastal Australian industry with shared marine corrosion environment.

For Australian marine boatbuilder projects specifically, see our Australia regional page for local lead times, ARBS 2026 exhibition presence and Box Hill North VIC head office service capability.

FAQ

How is styrene captured during fibreglass hand layup and VARIM?

Layered LEV at every mould (slot canopy hood at 0.5 to 1.0 m/s capture velocity) plus general ventilation at 4 to 6 ACH dilutes residual vapour. VARIM and RTM cut open emission by 70 to 90 percent but the vacuum exhaust line itself becomes the concentrated styrene source and must duct to carbon scrubber or biofilter. Ductwork is 316L stainless or polypropylene because polyester resin attacks galvanised zinc. WES is 50 ppm TWA, design target 20 ppm breathing zone.

What does NFPA 484 require for aluminium boatbuilders?

NFPA 484 (cross-referenced with NFPA 660 in 2025) treats aluminium fines as Class D combustible metal with Kst 200 to 415 bar.m/s. Capture at source through wet collector or dry collector with explosion suppression and isolation. Water deluge restricted because Al + H2O produces hydrogen. Class D extinguishing media (Met-L-X, Pyrene G-Plus, Lith-X). Ductwork bonded and grounded to less than 10 ohms. NFPA 484 prohibits sharing aluminium dust ductwork with steel or stainless dust ductwork.

How is a marine isocyanate spray booth designed?

AS/NZS 60079 Zone 1 inside the booth. AS 4114.2 sets construction and ventilation. Downdraft 0.4 to 0.5 m/s for OEM superyacht, cross-draft 0.5 to 0.6 m/s for production motor yacht. Dual-redundant interlocked extract fans on emergency power. Ductwork 304L or 316L stainless. Post-cure bake at 50 to 60 C. Isocyanate WES 0.005 ppm - 20 times more restrictive than styrene.

How is engine dyno commissioning exhaust handled?

Exhaust gas at 350 to 450 C from Cummins QSB6.7 through QSK19, CAT, MTU, MAN, Volvo Penta. 316L stainless 1.5 to 3.0 mm gauge. Bellows expansion joints at every wall penetration. Stack 2 to 3 m above roof. Internal cleanout every 4 m. Building height 8 to 10 m. CO monitors at 20 ppm warning and 30 ppm action.

What materials are specified for Australian boatbuilder ductwork?

Galvanised G90 0.8 to 1.2 mm for general supply (SBAL-V at GAL). 316L stainless 1.5 mm for fibreglass styrene exhaust, isocyanate spray exhaust, marine generator and battery room (SBAL-V at 316L). Galvanised 1.2 mm with conductive sealant for aluminium dust collection (SBFB-1500 spiral). 316L stainless 1.5 to 3.0 mm for engine dyno stack.

What air volumes for a mid-size Australian production boatbuilder?

15 to 30 m3/s total supply across the facility. Mould room 6 to 12 m3/s supply plus 6 to 12 m3/s LEV extract. Spray booth 4 to 8 m3/s per booth station. Engine commissioning 2 to 4 m3/s. Aluminium tinny line 10 to 25 m3/s dominated by 8 to 15 m3/s dust collection. Superyacht builder (SilverYachts, Echo Yachts) operates 50 to 150 m3/s installed.

How is composite autoclave ventilation handled?

Autoclave cure at 80 to 120 C and 2 to 4 bar absolute under nitrogen. Resin solvent flashes during ramp-up - dilute to under 25 percent of LEL. Layup room ISO 8 ambient or unclassified clean at 22 plus or minus 2 C and 50 plus or minus 10 RH. Vacuum bag debulk 0.5 to 1.0 m3/s through HEPA pre-filter. Ductwork 316L stainless.

What standards govern Australian marine boatbuilder ventilation?

AS 4114.2 spray booth, AS 1668.2 general ventilation, AS 4254 duct construction, AS/NZS 60079 hazardous gas atmosphere, AS 3957 dust hazard, NFPA 484 combustible metal, NFPA 660 (2025) combustible dust, NFPA 86 ovens. ISO 12215 small craft. CE RCD 2013/53/EU for EU export. AMSA, NSCV, ABP for Australian compliance. BIAA peak industry body.

What SBKJ machine model for an Australian boatbuilder fit-out?

SBAL-V auto duct line at GAL for general supply (12 to 14 weeks lead). SBAL-V at 316L stainless for process exhaust (14 to 16 weeks). SBFB-1500 spiral for dust collection and engine stack (10 to 12 weeks). SBSF-1525 stitchwelder for heavy-gauge fire-rated. SBAL-III for smaller builders. SBPC1500 plasma for custom fittings. Add 4 to 6 weeks ocean freight to Australian ports.

What is the WES for styrene, isocyanate and aluminium fines?

Styrene 50 ppm TWA and 100 ppm STEL. Isocyanate (TDI, MDI) 0.005 ppm TWA - the killer of marine topcoat. Aluminium metal and oxide 1 mg/m3 inhalable and 0.5 mg/m3 respirable, with NFPA 484 combustible metal classification overlay. Operator breathing-zone design target is typically 50 percent of WES.

Get an SBKJ marine boatbuilder duct quote →

Get in touch with the SBKJ engineering team

Spec'ing duct fabrication for a marine boatbuilder fit-out at Coomera, Henderson WA, Brisbane, Sydney, Lara or anywhere else in Australia? An SBKJ mechanical engineer replies within 12 hours — not a salesperson. We will scope your fit-out from the BIAA member onboarding paperwork through to the SBKJ Australia office at Box Hill North VIC, the ARBS 2026 stand in Sydney and the engineering and field service team for installation, commissioning and operator training.

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