How is MDF, particle board and laminate cutting handled for caravan cabinetry, kitchen, wardrobe and overhead locker fabrication?

Caravan interior cabinetry, kitchen bench, wardrobe, bunk, overhead locker and pop-top wood frame fabrication uses MDF, chipboard, structural plywood, Formica and HPL high-pressure laminate, ABS thermoformed plastic and PVC laminate as primary substrates. Cutting, routing, edge banding and sanding generate three coexisting hazards: respirable wood dust at WES 5 mg/m3 inhalable, formaldehyde off-gassing from the urea-formaldehyde and phenol-formaldehyde adhesives at WES 1 ppm STEL, and combustible dust per NFPA 660 with Kst 100 to 200 bar.m/s. Local dust extraction at every router, edge bander, panel saw and sander runs at 18 to 23 m/s transport velocity through cyclonic pre-separator and bag house filter. The dust collection system requires explosion vents on the bag house, rotary airlock isolation between the duct and the collector, and full equipotential bonding to less than 10 ohms. Formaldehyde mitigation runs through general dilution at 4 to 6 ACH plus localised LEV at the active glue and lamination station, supplemented by E0 or E1 grade panel material selection where economically feasible. Total joinery shop HVAC on a Jayco-scale operation runs 8 to 15 m3/s installed. Ductwork: galvanised 1.2 mm with conductive seam sealant for the dust collection (SBFB-1500 spiral), 316L stainless on the adhesive and contact-cement solvent extract (SBAL-V at 316L), galvanised 0.8 to 1.0 mm on general supply (SBAL-V at GAL).

What ductwork materials are specified for Australian caravan and RV manufacturer process zones?

Materials decision tree for an Australian caravan and RV manufacturer fit-out runs by process zone. General workshop supply air, administration, showroom and warehouse: galvanised G90 (Z275) 0.8 to 1.2 mm produced on SBKJ SBAL-V at standard configuration. Fibreglass layup table, gel coat hood, panel infusion line and resin store ventilation: 316L stainless 1.5 mm or polypropylene where exhaust temperature stays under 60 C — styrene and CR catalyst attack zinc within 12 months. Isocyanate spray booth exhaust and post-cure bake oven: 304L stainless 1.5 to 2.0 mm for spray exhaust, 316L stainless for post-cure bake at 50 to 60 C. Powder coat cure oven exhaust at 200 C: aluminised steel or 316L stainless 1.5 to 2.0 mm. Aluminium dust collection: galvanised 1.2 mm with conductive seam sealant and full equipotential bonding to less than 10 ohms (NFPA 484 compliance). MDF, particle board and timber dust collection: galvanised 1.2 mm with conductive sealant and explosion isolation (NFPA 660). LPG cylinder reception and gas commissioning: 316L stainless 1.5 mm with spark-free electrical. Li-ion battery commissioning bay: 316L stainless because HF release on thermal runaway attacks galvanised. SBKJ SBAL-V at GAL handles galvanised supply, SBAL-V at 316L handles stainless, SBFB-1500 spiral handles round dust collection, SBSF-1525 stitchwelder handles heavy-gauge fire-rated and 250 C smoke-spill runs.

What air volumes are typical for a mid-size Australian caravan manufacturer fit-out?

A typical Australian production caravan manufacturer running mixed fibreglass composite panel, aluminium skin and timber-MDF cabinetry at 500 to 3,000 units per year — Crusader Tullamarine, Concept Geelong, Goldstream Echuca, Galaxy Frankston, Tradition Echuca, Roadstar Geelong, Royal Flair Campbellfield, Spaceland Echuca scale — installs 15 to 30 m3/s total supply across the facility. The breakdown is panel layup and lamination at 4 to 8 m3/s supply with 4 to 8 m3/s LEV extract, isocyanate spray booth at 4 to 8 m3/s exhaust per booth station, post-cure bake oven at 1 to 2 m3/s exhaust at 50 to 60 C, joinery and MDF cabinetry at 5 to 10 m3/s general plus dust extraction, aluminium fabrication at 4 to 8 m3/s dust collection plus 2 to 4 m3/s welding fume capture, LPG cylinder reception at 1 to 2 m3/s exhaust, Li-ion battery commissioning at 1 to 2 m3/s exhaust, administration and showroom at 1 to 3 m3/s, and warehouse plus shipping at 1 to 2 m3/s. Jayco Dandenong VIC — Australia's biggest RV and caravan manufacturer producing across the Sterling, Discovery, Conquest, Penguin, Heritage, Crosstrak, Outback, Silverline, Stallion, Expanda, J-Pod and Adventurer ranges plus pop-top, slide-on and camper trailer variants and the Class C motorhome line — installs 80 to 150 m3/s across multi-bay parallel production with 100 to 200 units per week peak throughput. Avida at Emu Plains NSW — the second-largest builder across Wayfarer, Esperance, Eyre, Birdsville, Topaz, Magnum, Longreach, Ceduna, Bridgwater and Wilga motorhome plus caravan ranges — installs 40 to 80 m3/s. Class A motorhome builders (Winnebago Industries Australia at Toowoomba QLD, Sunliner at Newcastle NSW, Trakka at Wyong NSW) operate 20 to 50 m3/s with Mercedes Sprinter, VW Crafter, Iveco Daily and Fiat Ducato base-vehicle conversion lines.

What SBKJ machine model and configuration is recommended for an Australian caravan and RV manufacturer fit-out?

The standard SBKJ machine stack for an Australian caravan manufacturer fit-out runs five machine families. SBAL-V auto duct line in galvanised configuration produces 0.8 to 1.2 mm rectangular duct for general workshop supply, administration and warehouse ventilation at 8 to 15 m/min line speed. SBAL-V auto duct line in 316L stainless variant produces 1.5 mm rectangular duct for fibreglass layup exhaust, isocyanate spray booth exhaust, LPG cylinder reception and Li-ion battery commissioning ventilation at 4 to 7 m/min line speed. SBFB-1500 spiral tubeformer produces 100 to 1,500 mm round duct for aluminium dust collection, MDF and timber dust collection, composite carbon fibre and glass fibre dust extraction and return-air trunks at 12 to 20 m/min line speed. SBSF-1525 stitchwelder handles heavy-gauge fire-rated and 250 C smoke-spill duct sections at 1.2 to 2.0 mm gauge. SB-ZF1500 stitchwelder covers a similar envelope at smaller plant scale. SBAL-III three-line variant covers smaller builders with throughput under 500 units per year. SBPC1500 plasma cutter produces custom transitions and non-standard fittings. SBLR-600 louvre former handles acoustic silencer end caps and decorative showroom louvres. SBTF-1500, SBTF-1602 and SBTF-2020 variants cover portable spiral capability for refit and warranty work. Lead time is 12 to 14 weeks for galvanised SBAL-V, 14 to 16 weeks for the 316L stainless variant, 10 to 12 weeks for SBFB-1500 spiral, plus 4 to 6 weeks ocean freight to Australian ports.

Insights · HVAC Manufacturing — Caravan RV Motorhome Camper Trailer Pop-Top Slide-On

Caravan RV Motorhome Camper Trailer Pop-Top Slide-On Manufacturing HVAC Duct Guide — Jayco Dandenong, Avida Emu Plains, Crusader Tullamarine, NFPA 484 Aluminium, Styrene Extraction, ADR 38, AS 4254

A complete engineer-led specification guide for HVAC ductwork on Australian caravan, RV, motorhome, camper trailer, pop-top and slide-on manufacturer fit-outs — covering fibreglass gel coat and panel layup styrene capture, aluminium fines deflagration NFPA 484, isocyanate spray booth zone classification AS/NZS 60079, powder coat cure oven exhaust at 200 C, MDF and timber dust extraction NFPA 660, lithium-ion LiFePO4 battery off-gas H2 and HF, LPG cylinder reception AS/NZS 1596, AS 4114.2 spray booth, AS 4254 duct construction, ADR 38 trailer compliance, ADR 79 brake, AS/NZS 5048 trailer general, VSB14 light vehicle, VSB6 heavy vehicle modification, CIAA member onboarding — with the SBKJ duct fabrication machinery sized for caravan and RV manufacturer projects from Dandenong VIC to Emu Plains NSW, Tullamarine to Geelong, Echuca to Frankston, Campbellfield to Wyong NSW, Newcastle NSW to Toowoomba QLD.

By SBKJ Engineering Team · Published May 22, 2026 · 40 min read · Reviewed by SBKJ QA & Engineering

Why caravan manufacturing HVAC is the most layered mixed-process ventilation job in Australian light vehicle work

Walk through Jayco Caravan at Dandenong VIC, Avida at Emu Plains NSW, Crusader at Tullamarine VIC or Trakka Motorhomes at Wyong NSW and you will find — under one roof — a stack of demanding ventilation problems that few other Australian manufacturing sectors carry simultaneously. Polyester resin fibreglass panel layup generating styrene at 50 ppm WES alongside two-pack polyurethane topcoat generating isocyanate at 0.005 ppm WES alongside aluminium grinding and sanding generating combustible metal dust under NFPA 484 alongside MDF and chipboard routing generating wood dust and formaldehyde under NFPA 660 alongside LPG cylinder reception generating CH4 at 1.25 percent LEL alongside lithium-ion LiFePO4 battery commissioning generating H2 at 25 percent LEL and HF at 1.8 ppm STEL alongside powder coat cure oven running at 200 C alongside spray foam PUR insulation generating MDI isocyanate. A typical Australian production caravan plant runs nine to twelve distinct ventilation problems in parallel. An automotive paint shop runs three. A timber joinery shop runs two. A caravan plant is the most layered mixed-process ventilation job our SBKJ engineering team scopes anywhere in the Australian light vehicle and recreational vehicle sector.

This guide is the same engineering reference our SBKJ application team uses when a Caravan Industry Association of Australia (CIAA) member or a Recreational Vehicle Manufacturers Association (RVMA) member asks how to size duct fabrication for a caravan or RV manufacturer fit-out. We have scoped duct fabrication on jobs ranging from a single offroad camper trailer specialist in Mt Druitt NSW through to multi-bay parallel production lines and Class A motorhome conversion sheds. The patterns repeat. The standards stack — AS 4114.2 over AS 1668.2 over AS/NZS 60079 over AS 3957 over NFPA 484 over NFPA 660 over NFPA 86 over AS 5601 over AS/NZS 1596 over ADR 38 over VSB14 — is one of the most layered regulatory stacks we handle outside aerospace and pharma. Get the standards stack right and the rest of the design follows.

Eight conditions make caravan manufacturing HVAC harder than other industrial ventilation. First, the multi-toxicant problem — styrene, isocyanate, epoxy amine, MDF formaldehyde, solvent VOC, aluminium dust, wood dust, LPG and Li-ion off-gas 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 framework, skin and chassis members 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 combustible dust hazard from MDF and chipboard — joinery shop dust is NFPA 660 deflagration-capable with Kst 100 to 200 bar.m/s and requires explosion vents, isolation and full bonding. Fourth, the hazardous area density — every caravan plant has at least five AS/NZS 60079 zones (spray booth Zone 1, resin store Zone 2, paint mix room Zone 1, LPG cylinder reception Zone 1, Li-ion battery commissioning bay Zone 2) plus AS 3957 dust zones around aluminium and MDF dust collectors. Fifth, the LPG hazard — every caravan and motorhome carries an LPG installation feeding cooktop, hot water, heater and absorption fridge, and the cylinder reception, decanting and on-vehicle commissioning zones are Zone 1. Sixth, the Li-ion battery hazard — modern caravans have shifted heavily to LiFePO4 house batteries, and thermal runaway releases HF that destroys galvanised duct within hours. Seventh, the powder coat oven thermal load — chassis, A-frame, drawbar and external aluminium components powder coat at 200 C, demanding aluminised steel or 316L stainless duct with bake-out clean construction. Eighth, the volume scale — Jayco at Dandenong produces 100 to 200 units per week across multiple parallel build bays, the largest single-site recreational vehicle production facility in the southern hemisphere.

The Australian caravan and RV manufacturer landscape — Dandenong, Emu Plains, Tullamarine, Geelong, Echuca, Wyong, Newcastle, Toowoomba

Australian caravan, RV, motorhome, camper trailer, pop-top and slide-on manufacturing concentrates across six 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.

Dandenong and Greater Melbourne VIC. The single largest caravan and RV manufacturing cluster in Australia and one of the largest in the southern hemisphere. Jayco Caravan at Dandenong (ASX:JYC) is the country's biggest caravan, RV, motorhome and camper trailer manufacturer, producing the Sterling, Discovery, Conquest, Penguin, Heritage, Crosstrak, Outback, Silverline, Stallion, Expanda, J-Pod and Adventurer ranges plus dedicated pop-top, slide-on and camper trailer variants and the Class C motorhome line. The Dandenong campus is a multi-bay parallel production line at 100 to 200 units per week peak throughput, with chassis fabrication, panel sandwich press line, joinery shop, electrical and plumbing assembly, paint booth, gas commissioning, road test and pre-delivery inspection running in sequence and parallel. Crusader Caravans at Tullamarine VIC produces the Crusader, Excaliber and Eagle Wing ranges as Australian luxury caravan specialists. Concept Caravans at Geelong VIC produces the Concept, Innovation and Innovative ranges as offroad luxury specialists. Galaxy Caravans at Frankston VIC, Royal Flair Caravans at Campbellfield VIC, plus the broader Greater Melbourne RV and caravan supply chain.

Echuca VIC. A specialised caravan manufacturing town with multiple builders. Goldstream RV produces the Voyager and Storm ranges. Tradition Caravans, Spaceland Caravans and other Echuca-based manufacturers run smaller-volume production at 200 to 800 units per year per builder. The Echuca cluster shares the Murray River corridor logistics and a deep local supply chain in timber, aluminium and composite fabrication.

Emu Plains and Greater Sydney NSW. Avida at Emu Plains NSW is Australia's second-biggest builder across the Wayfarer, Esperance, Eyre, Birdsville, Topaz, Magnum, Longreach, Ceduna, Bridgwater and Wilga motorhome plus caravan ranges. The Emu Plains site is multi-bay parallel production at 30 to 80 units per week. Trakka Motorhomes at Wyong NSW produces luxury motorhome conversions on Mercedes Sprinter, Volkswagen Crafter and other premium base vehicles, with a specialised composite and joinery operation. Sunliner Motorhomes at Newcastle NSW produces Australian-built motorhome conversions on Sprinter, Iveco Daily and other base vehicles. Eagle Camper Trailers at Mt Druitt NSW produces offroad campers. Cub Campers at Sydney produces heritage offroad camper trailers across the Brumby, Stallion, Highline, Spacedock and Daintree ranges. MDC Caravans at Geelong and Brisbane (Mobile Distributors Co) produces the Forbes, Pioneer and Off Road ranges.

Toowoomba QLD and South-East Queensland. Winnebago Industries Australia at Toowoomba QLD produces Class A, Class C and Class B motorhomes plus the Trakka co-production line, in a multi-bay parallel production facility. MDC Brisbane operates a parallel line to the Geelong MDC site. The South-East Queensland cluster shares logistics, supply chain and the trade show circuit with the Coomera marine cluster covered in the marine yacht boatbuilder guide.

Coromal Bayswater WA legacy. Coromal Caravan Pty Ltd at Bayswater WA was a long-standing WA-based builder across the Princeton, Bushland, Outback, Pioneer and Lifestyle ranges. Acquired by Apollo Tourism Leisure and discontinued in 2020, the legacy Coromal hulls remain in the touring fleet. The Bayswater facility represents a sunset chapter of WA-based caravan manufacturing.

Apollo and Tourism Holdings rental fleet operations. Apollo Motorhomes (formerly an OEM manufacturer) now operates Australia's largest motorhome rental fleet across ApolloRV, Star RV, Cheapa Campa, EnduraRV, ENDeavour, Maui and EuroCampers brands. Tourism Holdings (THL, NZ-owned) operates GO RV, Star RV, Britz and Maui rental fleet across Australia and New Zealand. Talvor Motorhomes (NZ-owned) operates a parallel rental brand. The rental fleet operators run major refurbishment and refit facilities at major cities — refit work overlaps with new-build HVAC requirements at smaller scale but higher frequency.

Each cluster has a distinctive process mix. Dandenong is volume-dominated with mixed fibreglass composite panel, aluminium skin and timber-MDF cabinetry. Echuca is mid-volume caravan production. Emu Plains is mid-volume caravan plus motorhome conversion. Wyong and Newcastle are luxury motorhome conversion on premium base vehicles. Toowoomba is Class A motorhome conversion at scale. The ventilation design must match the cluster's process mix and the shed's destination market.

Caravan and RV manufacturer process zones — twelve distinct ventilation problems under one roof

Inside a typical Australian production caravan and RV manufacturer there are twelve 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 wood, aluminium or composite plug for new model first articles, sandwich-panel press tooling, body skin master moulds and prototype plug for new floor plans. 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 tooling room temperature must hold 22 C plus or minus 2 to ensure stable resin cure on first article panels.

Fibreglass gel coat, hand layup, spray-up, VARIM and panel infusion. The single highest-volume process emission in a production caravan plant. Jayco, Avida and the larger builders run sandwich-panel infusion lines producing 6 to 8 m insulated composite wall, floor and roof panels with PUR foam core, fibre-reinforced FRP outer skin, aluminium pre-formed corner profile and Formica or HPL interior lamination. 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. Resin systems include Sika, Resoltech, SP Systems, West System, Mas Epoxy plus local Australian polyester and vinylester suppliers. Sandwich-panel makers Bondor, Kingspan, Crane and Sahbox supply pre-laminated panels to smaller caravan builders avoiding in-house composite fabrication. 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. Limited in mainstream caravan production but present at performance-oriented luxury builders and at the high end of the Trakka and luxury composite motorhome segment. CFRP, GRP and Kevlar laminate processing with autoclave cure at 80 to 200 C and 2 to 7 bar absolute pressure under nitrogen blanket. Post-cure VOC emission of epoxy thinner, IPA, MEK and ethyl acetate during cure ramp-up. Ductwork 316L stainless on autoclave vent line.

Aluminium extrusion cut, form, weld and rivet — caravan skin, framework and chassis. Jayco, Avida, Crusader, Concept, Goldstream, Galaxy, Tradition, Roadstar, Royal Flair, Spaceland and the broader CIAA membership all run aluminium fabrication as a core process. Marine-grade 5083, 5086 and 5052 alloy plate for caravan skin and body panels, 6061 and 6082 structural extrusion for chassis members, A-frame, drawbar, chassis-mount cross-members and wheel mounts, plus 6063 architectural extrusion for window framing, door framing and roll-formed body trim. 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 (Cr VI 0.05 STEL relevant if using 5XXX filler over Cr-bearing substrate) 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.

Steel hot-dip galvanised chassis fabrication. Jayco, Avida, Crusader and the broader caravan sector run steel hot-dip galvanised chassis, A-frame, drawbar and coupling fabrication per AS/NZS 4680 hot-dip galvanise specification at Z275 grade minimum. CNC plasma cut, brake press form, MIG and submerged-arc weld, post-cut paint touch-up. The galvanise pickle line uses hydrochloric acid bath followed by zinc kettle at 450 C — separate process line typically subcontracted to specialist galvanise houses. The chassis fabrication shed runs welding fume capture, plasma cutting fume capture and post-cut grinding dust extraction. Iron oxide WES 5 mg/m3, manganese 0.2 mg/m3 respirable, Cr VI 0.05 STEL on chromium-bearing steels. Ductwork 316L stainless on welding fume capture, galvanised 1.2 mm on plasma fume capture.

Panel construction and insulated composite sandwich panel. Jayco insulated panel walls, ceiling and floor — PUR foam core (40 to 80 mm thick), fibre-reinforced FRP outer skin (0.5 to 1.5 mm), aluminium pre-formed corner profile and Formica, HPL or vinyl interior lamination. Adhesive lamination uses PU contact adhesive (Sikaflex 252 and 521 UV), epoxy bonding adhesive or hot-melt PUR adhesive. The panel press operates at 60 to 120 C platen temperature and 0.5 to 2.0 bar press pressure for 5 to 30 minutes cure time per panel. Off-gassing during panel cure includes residual MDI isocyanate from PUR foam, polyol vapour, blowing agent (pentane on standard PUR foam, water-blown on environmental PUR), and residual epoxy amine on epoxy-bonded panels. Localised LEV at the press exit at 0.5 to 1.0 m/s capture velocity, 316L stainless ductwork because MDI attacks galvanised.

Joinery, cabinet making, timber, MDF and laminate. Cabinetry, kitchen, bench, wardrobe, bunk, overhead locker, pop-top wood frame, benchtop and HPL panel cut. MDF and chipboard cutting generates respirable wood dust at 5 mg/m3 inhalable WES, formaldehyde off-gassing from urea-formaldehyde adhesive at 1 ppm STEL, combustible dust per NFPA 660 with Kst 100 to 200 bar.m/s. Edge banding uses hot-melt EVA adhesive with minimal solvent. Contact cement at carcase assembly with toluene 50 ppm WES, MEK 200 ppm. Vacuum-formed ABS thermoformed plastic, polystyrene EPS and XPS foam, PIR and PUR rigid foam plus Aerocel and Armaflex elastomer foam insulation cutting generates polymer dust and trace formaldehyde. Glass wool and rock wool insulation handling generates respirable fibre. Total joinery shop HVAC on a Jayco-scale operation runs 8 to 15 m3/s installed. Smaller builders run 3 to 8 m3/s.

Pre-paint primer, topcoat and luxury composite finish. Two-component polyurethane topcoat with isocyanate (TDI, MDI) at 0.005 ppm WES. Imron, Awl-Grip on luxury units, Mankiewicz, PPG, Dulux, Akzo Nobel, ZEUS, Sika. Anti-fouling rare in caravan but present on amphibious off-road slide-on. Spray booth Zone 1 per AS/NZS 60079 with downdraft at 0.4 to 0.5 m/s for OEM luxury caravan and Class A motorhome work and cross-draft at 0.5 to 0.6 m/s for production volume. 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.

Powder coat. Chassis, A-frame and external aluminium component powder coat as standard finish across the caravan and RV sector. Akzo Nobel Powder, Dulux, Jotun, Tiger, IGI and PPG powder systems. Phosphate or chromate pretreatment with iron phosphate or zinc phosphate conversion coating. Electrostatic spray gun application. Powder cure oven at 180 to 200 C for 15 to 20 minutes on epoxy, polyester or polyurethane powder resin. Powder overspray dust collection at 18 to 23 m/s transport velocity through cyclonic pre-separator and bag filter. Oven exhaust at 200 C through aluminised steel or 316L stainless duct. Isocyanate cure during the bake produces residual TCDI off-gas.

Assembly line and chassis-up build. Chassis-up build sequence: floor pan, wall, roof, window, door, furniture install, kitchen, bathroom, bedroom, lounge, stove, fridge, hot water service, HVAC test, electrical, plumbing. Jayco production line at Dandenong runs 100 to 200 units per week peak across multiple parallel bays. Avida at Emu Plains runs 30 to 80 units per week. The assembly bay ventilation is general dilution at 4 to 6 ACH with localised solvent extract at glue and sealant stations (silicone Sikaflex VOC, PU foam expansion, MDI urethane, polyester and vinylester resin touch-up). Make-up air for the assembly bay must accommodate the open doors during chassis movement plus the localised solvent extract.

Electrical, 12V/24V/240V wire and lithium-ion LiFePO4 battery commissioning. Modern caravan production has shifted heavily from AGM and gel batteries to lithium iron phosphate (LiFePO4) house battery banks at 100 to 600 Ah per unit. Jayco, Avida, Crusader, Concept, Trakka, Sunliner and Winnebago Industries Australia all install LiFePO4 as standard on touring caravans, Class A and Class C motorhomes and offroad campers. The build-side ventilation must accommodate two distinct hazards. First, the routine bulk-charge commissioning generates negligible gas emission from LiFePO4 chemistry. Second, the rare but consequential thermal runaway event releases H2 (25 percent LEL trigger), HF (1.8 ppm STEL — the killer), CO, organic carbonate vapour and lithium oxide aerosol. The thermal runaway response demands AS/NZS 60079 Zone 2 classification of the battery commissioning bay, dedicated extract fan on emergency power at 4 to 8 ACH, fixed gas detection, and Class D extinguishing media.

LPG cylinder reception, gas system and on-vehicle commissioning. Every modern Australian caravan, motorhome, camper trailer and slide-on carries an LPG installation feeding cooktop, hot water, space heating and refrigerator. Truma combi heater, Dometic absorption fridge, Suburban water heater, Trumatic combi heater. LPG cylinder reception, storage and decanting zone Zone 1 per AS/NZS 60079 within 1 m of cylinder valves and Zone 2 within 3 m, per AS/NZS 1596 LPG storage and handling. AS 5601 gas installation governs the on-vehicle LPG system design and pressure testing. AGA AGCert certification mandatory on the completed installation. Ventilation 6 to 12 ACH continuous with low-level extract grilles (LPG denser than air at 1.55 specific gravity). Ductwork 316L stainless.

Codes and standards — the caravan and RV manufacturer regulatory stack

No caravan or RV manufacturer ventilation design is complete without explicit verification against a stack of overlapping standards covering both the build-shed envelope and the vehicle-side compliance regime. The eighteen references below are the primary references for Australian caravan and RV manufacturer fit-outs; in any given project at least ten apply and often all eighteen.

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. Every isocyanate topcoat booth at Jayco, Avida, Crusader, Concept, Trakka, Sunliner and Winnebago Industries Australia 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 fibreglass layup, aluminium welding, dust collection, MDF cutting and battery handling. Cross-references AS 4114.2 for spray-specific requirements.

AS 1668.1 — The use of mechanical ventilation for fire and smoke control. Section 1 covers smoke-spill duct design for assembly occupancies including showroom spaces. Smoke-spill duct rated at 250 C for 2 hours per AS 1530.4. SBSF-1525 stitchwelder is the SBKJ machine for smoke-spill heavy-gauge sections.

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. Caravan plant buildings with bake-out chambers, spray booths, resin stores and Li-ion battery commissioning bays are typically NCC Class 8 industrial occupancy with Class 7b storage component, fire-resistance ratings ranging from 60 to 120 minutes on penetrations and 240 minutes on bake-out fire-rated runs.

AS 1851 — Routine service of fire protection systems and equipment. Sets the maintenance schedule for fire and smoke dampers, sprinkler systems and detection. Caravan plant buildings with isocyanate spray booths, resin stores, MDF dust collection, aluminium dust collection, LPG cylinder reception, Li-ion battery commissioning bays and powder coat ovens carry one of the highest densities 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. Caravan plant spray booth interior is Zone 1, booth surrounds are Zone 2, resin store is Zone 2, LPG cylinder reception is Zone 1, Li-ion battery commissioning bay is Zone 2, powder coat cure oven interior is Zone 1, paint cure oven is Zone 1, vehicle fuel system commissioning area is Zone 1. 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, paint thinner, adhesive solvent and propane storage. Sets bunding, ventilation, separation and fire-resistance rules.

AS/NZS 1596 — The storage and handling of LP Gas. Covers LPG cylinder reception, storage, decanting and on-vehicle installation. Cross-references AS/NZS 60079 for hazardous area zone classification around cylinder valves and bulk storage.

AS 5601 — Gas installations. Covers the on-vehicle LPG system design, pipework, fittings, appliance connection, pressure testing and certification. AGA AGCert is the industry certification scheme. Every caravan and motorhome gas installation requires AGCert sign-off before vehicle delivery.

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 chassis fabrication, framework cutting and external skin work triggers Zone 22 around the dust collector and Zone 21 inside the collector itself. MDF and chipboard cutting dust around the joinery shop triggers similar classification with lower deflagration severity than aluminium but still NFPA 660 hazard.

NFPA 484 — Standard for Combustible Metals. The international best-practice reference for aluminium handling, cross-referenced with NFPA 660 in the 2025 consolidation. Australian caravan builders running aluminium framework, chassis, skin and component fabrication 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. Caravan plant 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 660 also covers MDF, chipboard and wood dust handling at the joinery shop.

NFPA 86 — Standard for Ovens and Furnaces. Governs the powder coat cure oven at 180 to 200 C, paint cure oven at 60 to 80 C, epoxy primer cure oven at 100 to 120 C, autoclave composite cure at 180 to 200 C and 7 bar pressure, plus any wood drying oven. Pre-purge, flame supervision, high-temperature limit and explosion relief apply scaled to the oven volume.

NFPA 30 — Flammable and Combustible Liquids Code. Overlay reference to AS 1940 for export builds and US-based AHJ work. NFPA 13 covers sprinkler design. NFPA 70 (NEC) covers electrical including hazardous area classification.

AS/NZS 1554 series — Structural steel welding. Part 1 covers carbon steel, part 6 covers stainless steel. Relevant for chassis fabrication and structural framework. AS 1665 covers aluminium welding.

ISO 9001, ISO 14001, ISO 45001. Quality management, environmental management and occupational health and safety management. CIAA member onboarding typically requires ISO 9001 minimum with ISO 45001 increasingly common.

ADR (Australian Design Rules) — federal vehicle-side compliance. ADR 38 governs trailer brake systems on caravans and camper trailers over 750 kg ATM. ADR 79 governs vehicle emissions. ADR 80 governs vehicle braking. AS/NZS 5048 covers trailer general design including chassis, A-frame, drawbar and coupling.

VSB14 and VSB6 — Vehicle Standards Bulletins. VSB14 National Code of Practice for Light Vehicle Construction and Modification covers caravan and camper trailer body fit-out, electrical, plumbing and gas systems. VSB6 covers heavy vehicle modification relevant for Class A motorhome conversion on Iveco Daily, Mercedes Sprinter Cab Chassis and other heavy vehicle base.

The vehicle-side compliance regime (ADR, VSB14, VSB6, state Vehicle Operating Standards) is administered by the Department of Infrastructure federally and by VicRoads, Transport for NSW, TMR QLD, DIT SA, DoT WA, DSG Tasmania and DIPL NT at the state level. The build-shed envelope (AS 4114.2, AS 1668.2, AS/NZS 60079, AS 3957, NFPA 484, NFPA 660, NFPA 86, AS 5601, AS/NZS 1596) is administered by state WorkSafe regulators and state building authorities. The build-shed PCBU must demonstrate dual compliance during routine and incident-triggered inspections.

Fibreglass styrene extract caravan — the highest-volume ventilation problem in production caravan composite work

Styrene from polyester and vinylester resin is the single most demanding ventilation problem in any production caravan plant running open-mould layup or vacuum-assisted sandwich panel 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 CIAA 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 layup table or panel press — 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 layup room at 4 to 6 air changes per hour dilutes residual vapour and prevents accumulation in roof voids and overhead crane gantries. For closed-mould VARIM and sandwich-panel press 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 caravan plants 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 caravan plant layup room runs 4 to 8 m3/s supply with 4 to 8 m3/s LEV extract at the active hoods. A Jayco-scale operation with parallel sandwich-panel infusion lines plus secondary layup stations supplies 20 to 40 m3/s total across the composite zone. The supply train must include a make-up air conditioning load of 100 to 250 kW cooling capacity for Australian summer dehumidification and 60 to 120 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 layup-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 fines caravan — chassis, framework and skin dust collection

Aluminium dust from grinding, sanding, polishing, plasma cutting and laser cutting is NFPA 484 Class D combustible metal with deflagration potential. Australian caravan builders running 5083 and 5086 marine-grade aluminium skin, 5052 sheet for body panels, 6061 and 6082 structural extrusion for chassis members and 6063 architectural extrusion — Jayco, Avida, Crusader, Concept, Goldstream, Galaxy, Tradition, Roadstar, Royal Flair, Spaceland, Trakka, Sunliner, Winnebago Industries Australia and the broader CIAA membership — 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 Crusader, Concept or Goldstream caravan plant typically runs 4 to 8 m3/s through 10 to 20 grinding and polishing stations. Jayco at Dandenong runs 15 to 30 m3/s across multi-bay parallel chassis and framework fabrication. A SilverYachts-scale superyacht builder runs 30 to 80 m3/s but caravan plants are 5 to 10 times smaller in dust collection scale. The fan motor 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 caravan — luxury topcoat application

Caravan and motorhome topcoat application using two-component polyurethane systems (PPG, Dulux, Mankiewicz, Akzo Nobel, Imron, Awl-Grip on luxury units, ZEUS, Sika) 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 caravan and motorhome 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, IPA 400 ppm, acetone 250 ppm, toluene 50 ppm, MIBK 50 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 luxury caravan and Class A motorhome work (Crusader Excaliber, Concept Innovation, Trakka, Winnebago Industries Australia Class A) and cross-draft at 0.5 to 0.6 m/s for production volume work (Jayco production line, Avida, Goldstream, Galaxy, Tradition, Roadstar). Same velocity envelope as automotive paint booths but with much higher booth volumes because caravan lengths run 4 to 9 m, Class A motorhome lengths run 8 to 12 m and large fifth-wheelers reach 10 to 12 m. A typical caravan isocyanate booth has internal volume of 80 to 800 m3 covering a single hull or hull section.

AS 4114.2 section 4 sets the booth construction and ventilation rules. The face velocity floor in the standard 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 caravan isocyanate exhaust fails within a single production season. Field experience at Australian caravan plants 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 and disruption of the production line.

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. Jayco and Avida running high topcoat throughput install RTO at 15 to 30 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.

Powder coat oven exhaust — chassis, A-frame and external aluminium component finish

Powder coat is the standard external finish for caravan chassis, A-frame, drawbar, coupling, mud guards, external aluminium components and accessory hardware across the Australian caravan and RV sector. Akzo Nobel Powder, Dulux, Jotun, Tiger, IGI and PPG powder systems dominate the Australian market with epoxy primer, polyester topcoat and polyurethane resin variants for different durability and UV-resistance requirements.

The powder coat process runs four sequential stages. Pretreatment uses iron phosphate or zinc phosphate conversion coating to prepare the aluminium or steel substrate for powder adhesion. Drying oven at 80 to 120 C removes the water and pretreatment chemistry residue. Electrostatic spray gun application deposits the powder at 30 to 90 kV electrostatic charge. Powder cure oven at 180 to 200 C for 15 to 20 minutes cures the powder to a continuous film.

Powder overspray dust collection at the spray booth runs at 18 to 23 m/s transport velocity through cyclonic pre-separator and bag filter. The collected powder is typically recycled back to the spray system at 70 to 90 percent recovery rate. The bag filter requires explosion vent because powder is combustible (Kst 30 to 150 bar.m/s, lower than aluminium or wood but still deflagration-capable). Ductwork on powder overspray collection: galvanised 1.0 to 1.2 mm with conductive seam sealant, or aluminised steel for higher cycle life.

Powder cure oven exhaust at 200 C requires aluminised steel or 316L stainless 1.5 to 2.0 mm. The exhaust gas contains residual isocyanate cure off-gas (from polyurethane powder), formaldehyde (from epoxy crosslinker), styrene (from polyester powder) and trace metal oxide aerosol. Stack discharge above roof with bellows expansion joints at every wall penetration. Stack velocity 8 to 12 m/s.

Oven volume on a Jayco-scale powder coat line runs 30 to 80 m3 with throughput of 50 to 150 chassis per day. Smaller caravan plants run 10 to 30 m3 oven volume. The exhaust airflow scales to 1 to 3 m3/s at 200 C, which is equivalent to 0.6 to 1.8 m3/s at ambient.

NFPA 86 covers oven safety including pre-purge (4 air changes minimum before burner ignition), flame supervision, high-temperature limit (typically 220 C trip on a 200 C set point), and explosion relief. AS/NZS 60079 Zone 1 inside the oven during pre-purge and at startup. SBKJ machinery: SBSF-1525 stitchwelder for the heavy-gauge oven exhaust duct, SBAL-V at 316L for the rectangular plenum sections, SBFB-1500 spiral for round riser to the stack.

MDF, particle board and joinery dust collection — caravan cabinetry, kitchen and bedroom fit-out

Caravan interior cabinetry, kitchen bench, wardrobe, bunk, overhead locker and pop-top wood frame fabrication uses MDF, chipboard, structural plywood, Formica and HPL high-pressure laminate, ABS thermoformed plastic and PVC laminate as primary substrates. The joinery shop is one of the largest single ventilation loads in a caravan plant and runs three coexisting hazards.

First, respirable wood dust at WES 5 mg/m3 inhalable. Operator exposure is unforgiving because the dust is fine enough to penetrate the upper respiratory tract and reach the lung alveoli. Chronic exposure correlates with nasal sinus cancer and obstructive lung disease.

Second, formaldehyde off-gassing from the urea-formaldehyde and phenol-formaldehyde adhesives at WES 1 ppm STEL. The formaldehyde concentration in raw MDF and chipboard varies by panel grade — E1 grade emits up to 1 ppm continuous, E0 grade emits under 0.5 ppm, Super E0 emits under 0.3 ppm. The formaldehyde mitigation strategy combines panel-grade selection, general dilution at 4 to 6 ACH and localised LEV at the active glue, lamination and edge-banding stations.

Third, combustible dust per NFPA 660 (formerly NFPA 664) with Kst 100 to 200 bar.m/s. The MDF and chipboard dust is deflagration-capable and the joinery shop dust collection requires explosion vents on the bag house, rotary airlock isolation between the duct and the collector, and full equipotential bonding to less than 10 ohms.

Local dust extraction at every router, edge bander, panel saw, sander, vacuum-formed plastic trimmer and ABS cutter runs at 18 to 23 m/s transport velocity through cyclonic pre-separator and bag house filter. The cyclonic pre-separator removes the bulk of the chip and shaving load at 90 to 95 percent efficiency, leaving the fine dust (under 100 microns) to be captured by the bag filter at 99.5 percent efficiency or better.

Contact cement and adhesive solvent capture at every gluing station runs through localised exhaust at 0.5 to 1.0 m/s capture velocity. Toluene 50 ppm WES, MEK 200 ppm, ethyl acetate 200 ppm. Ductwork 316L stainless because solvent attack on galvanised is significant over the joinery shop's operational life.

Total joinery shop HVAC on a Jayco-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 assembly bay so the finished cabinetry can move directly into the hull. SBKJ machinery: SBFB-1500 spiral for the round dust collection trunks, SBAL-V at GAL or 316L for the general supply and adhesive solvent extract, SBSF-1525 stitchwelder for the heavy-gauge collector housing.

Lithium-ion LiFePO4 battery commissioning ventilation — H2 and HF off-gas

Modern caravan and RV production has shifted heavily from AGM and gel batteries to lithium iron phosphate (LiFePO4) house battery banks. Jayco, Avida, Crusader, Concept, Trakka, Sunliner and Winnebago Industries Australia install LiFePO4 as standard on touring caravans, Class A and Class C motorhomes and offroad campers at 100 to 600 Ah capacity per unit. Premium Class A motorhomes carry banks of 2 to 6 batteries totalling 1,200 to 3,600 Ah.

The build-side ventilation of the Li-ion battery commissioning bay accommodates two distinct hazards. First, the routine bulk-charge commissioning generates negligible gas emission from LiFePO4 chemistry — the chemistry is intrinsically more stable than NMC or LCO chemistries used in EV batteries. Routine commissioning requires only general dilution ventilation at 4 to 6 ACH with no special zone classification.

Second, the rare but consequential thermal runaway event releases a cocktail of hazardous off-gas — H2 at 25 percent LEL trigger (the explosive hazard), HF at 1.8 ppm STEL (the toxicity killer — HF is acutely toxic and chronically damaging to bone and tissue), CO at 30 ppm TWA, organic carbonate vapour (DMC, EMC, EC, DEC from electrolyte decomposition) at 50 to 200 ppm range, and lithium oxide aerosol. The thermal runaway off-gas profile drives the ventilation design even though the event is rare in normal commissioning.

The thermal runaway response demands AS/NZS 60079 Zone 2 classification of the battery commissioning bay (gas atmosphere not normally present but possible in fault condition), dedicated extract fan on emergency power at 4 to 8 ACH, fixed gas detection (H2 at 10 percent LEL warning, 25 percent LEL action; HF at 0.9 ppm STEL warning, 1.8 ppm action; CO at 30 ppm action), and Class D extinguishing media. Water deluge is restricted because Li plus H2O produces Li(OH) plus H2 with significant hydrogen evolution.

The battery commissioning bay must be physically separated from the LPG cylinder reception, paint store and resin store to prevent multi-hazard incident escalation. A 3 m separation distance is typical, with fire-rated wall construction (FRL 120/120/120) where the separation is less than 3 m.

Ductwork is 316L stainless 1.5 mm because HF aerosol attacks galvanised zinc within hours of release. Galvanised duct in a Li-ion thermal runaway scenario fails catastrophically before the emergency response can isolate the duct. 316L stainless survives the event with damage limited to the polymer gaskets and the immediate vicinity of the runaway battery.

Total Li-ion battery commissioning bay HVAC on a Jayco-scale operation runs 1 to 2 m3/s installed. Smaller builders run 0.5 to 1.0 m3/s. The bay is typically 50 to 200 m2 with 5 to 20 batteries under simultaneous commissioning. SBKJ machinery: SBAL-V at 316L stainless for the rectangular extract duct, SBFB-1500 spiral for the round riser to the discharge stack.

LPG cylinder reception and gas commissioning ventilation

Every modern Australian caravan, motorhome, camper trailer and slide-on carries an LPG installation feeding cooktop, hot water, space heating and refrigerator. The LPG appliance ecosystem includes Truma combi heater and water heater, Dometic absorption fridge and air conditioner, Suburban water heater, Trumatic combi heater, Webasto and Eberspächer diesel heaters as alternatives to LPG space heating, Houghton air conditioner and Aircommand caravan air conditioner as LPG-independent options.

The LPG cylinder reception, storage and decanting zone is classified AS/NZS 60079 Zone 1 within 1 m of cylinder valves and Zone 2 within 3 m, per AS/NZS 1596 LPG storage and handling. AS 5601 gas installation governs the on-vehicle LPG system design and pressure testing. AGA AGCert certification is mandatory on the completed installation. Every caravan and motorhome gas installation requires AGCert sign-off before vehicle delivery — the certifier verifies pipework integrity, leak testing, appliance commissioning and ventilation adequacy on the completed vehicle.

Build-shed ventilation for the LPG cylinder reception runs at 6 to 12 ACH continuous with low-level extract grilles (LPG is denser than air at 1.55 specific gravity and accumulates at floor level), fixed CH4 and LPG gas detection at 25 percent LEL warning and 50 percent LEL action thresholds, spark-free electrical switchgear, and dual-redundant extract fans on emergency power. The extract grilles are positioned within 150 mm of the floor at 1 to 2 m spacing along the perimeter wall.

The on-vehicle gas commissioning station is a separate enclosure inside the build shed where each completed unit is pressure-tested, leak-tested and AGCert certified. The commissioning station ventilation is general dilution at 4 to 6 ACH plus a portable LPG sniffer used by the certifier during the leak test. Some larger plants (Jayco, Avida) operate dedicated gas commissioning rooms with Zone 1 classification and dedicated extract.

Ductwork on the LPG cylinder reception and gas commissioning ventilation: 316L stainless 1.5 mm because LPG odorant (ethanethiol) attacks galvanised zinc over 5 to 10 years of operational life. Service life on 316L is 25 to 30 years versus 5 to 8 years on galvanised. SBKJ machinery: SBAL-V at 316L stainless for the rectangular extract duct, SBFB-1500 spiral for the round riser to the discharge stack.

Total LPG cylinder reception HVAC on a Jayco-scale operation runs 1 to 2 m3/s installed. Smaller builders run 0.5 to 1.0 m3/s. The reception bay is typically 100 to 300 m2 with 50 to 500 cylinders in active storage.

Jayco Dandenong HVAC and the Greater Melbourne caravan precinct

Jayco Caravan at Dandenong VIC operates the largest single-site caravan, RV, motorhome and camper trailer production facility in Australia and one of the largest in the southern hemisphere. The Dandenong campus produces the Sterling, Discovery, Conquest, Penguin, Heritage, Crosstrak, Outback, Silverline, Stallion, Expanda, J-Pod and Adventurer caravan ranges plus dedicated pop-top, slide-on and camper trailer variants, the Class C motorhome line and the toy hauler range. Annual production has consistently exceeded 8,000 to 12,000 units across the multi-bay parallel production with 100 to 200 units per week peak throughput. Jayco's HVAC load is the benchmark for production caravan manufacturers globally.

The Jayco production process runs eleven sequential stages, each with distinct ventilation signature. Chassis fabrication (steel plasma cut, weld, hot-dip galvanise) at 4 to 8 m3/s welding fume capture plus dust extraction. Aluminium framework and skin fabrication at 6 to 10 m3/s dust collection. Sandwich panel infusion (PUR foam core, FRP outer skin, aluminium corner profile, Formica interior) at 8 to 15 m3/s extract. Joinery and MDF cabinetry at 8 to 15 m3/s dust collection plus general dilution. Pre-paint primer at 2 to 4 m3/s booth exhaust. Powder coat on chassis and external components at 2 to 4 m3/s booth plus oven exhaust at 200 C. Isocyanate topcoat at 4 to 8 m3/s exhaust per booth station with three to six booths in parallel. Post-cure bake at 1 to 2 m3/s per booth. Assembly line (window, door, furniture, kitchen, bathroom, electrical, plumbing, HVAC, gas) at 4 to 8 m3/s general dilution plus solvent extract at glue stations. LPG cylinder reception and gas commissioning at 1 to 2 m3/s exhaust. Li-ion battery commissioning at 1 to 2 m3/s exhaust. QC, road test, water test, leak test and pre-delivery inspection at 1 to 2 m3/s general.

Total Jayco Dandenong installed HVAC supply runs 80 to 150 m3/s across the campus with isocyanate spray exhaust at 25 to 50 m3/s through abatement, dust collection at 20 to 40 m3/s through wet and dry collectors, and general assembly bay ventilation at 30 to 60 m3/s. Ductwork stock on site exceeds 15 to 25 km of supply (galvanised) plus 8 to 12 km of extract (316L stainless on isocyanate and LPG, polypropylene on styrene), plus 4 to 6 km of round dust collection (galvanised). The duct fabrication challenge on a Jayco-scale operation is sustained at 200 to 500 m per day during peak fit-out periods.

Crusader at Tullamarine VIC runs a similar process at smaller scale — 30 to 60 luxury units per week across Crusader, Excaliber and Eagle Wing ranges. Total installed HVAC is 20 to 40 m3/s. Concept at Geelong VIC runs offroad luxury at 20 to 40 units per week with 15 to 30 m3/s installed. Galaxy at Frankston, Royal Flair at Campbellfield and the broader Greater Melbourne cluster collectively install 60 to 120 m3/s of HVAC capacity across the secondary builders.

The Greater Melbourne caravan precinct — Jayco, Crusader, Concept, Galaxy, Royal Flair plus the Echuca cluster (Goldstream, Tradition, Spaceland) — represents one of the largest concentrations of caravan manufacturing HVAC infrastructure in the southern hemisphere. The cluster supports the annual Victorian Caravan Camping Supershow and feeds dealer networks across Australia and selected export markets.

Avida Emu Plains — the second-biggest Australian caravan and motorhome manufacturer

Avida at Emu Plains NSW is Australia's second-biggest caravan and motorhome manufacturer across the Wayfarer, Esperance, Eyre, Birdsville, Topaz, Magnum, Longreach, Ceduna and Bridgwater caravan ranges plus the Wilga motorhome line. The Emu Plains campus is a multi-bay parallel production line at 30 to 80 units per week peak throughput, running mixed caravan and motorhome production through partly shared assembly bays with dedicated motorhome conversion lines for the Wilga.

The Avida production process runs a similar sequence to Jayco at smaller scale. Steel chassis fabrication, aluminium framework and skin, panel construction, joinery, paint, assembly, electrical, plumbing, gas, QC and pre-delivery. The Wilga motorhome line adds base-vehicle conversion (Iveco Daily, Mercedes Sprinter, VW Crafter cab chassis) with associated heavy vehicle modification per VSB6.

Total Avida Emu Plains installed HVAC supply runs 40 to 80 m3/s. The breakdown follows the Jayco template at half the scale — 8 to 15 m3/s on sandwich panel and composite layup, 6 to 12 m3/s on isocyanate spray and powder coat, 8 to 12 m3/s on joinery and MDF, 5 to 8 m3/s on aluminium framework dust collection, 4 to 6 m3/s on chassis welding and steel work, and the balance on assembly, LPG and battery commissioning.

Avida's HVAC challenge is the mixed caravan-motorhome production through shared bays. The motorhome conversion requires the cab chassis to enter the paint and assembly bays at full height (3.0 to 3.5 m tall) versus the caravan body at 2.5 to 3.0 m tall. The HVAC supply and extract must accommodate both height ranges without compromising face velocity at the spray booth or capture velocity at the dust collection hoods.

Ductwork at Emu Plains follows the Jayco material specification. Galvanised G90 0.8 to 1.2 mm for general supply (SBAL-V at GAL). 316L stainless 1.5 mm for isocyanate spray, fibreglass styrene, LPG cylinder reception and Li-ion battery commissioning (SBAL-V at 316L). Galvanised 1.2 mm with conductive sealant for aluminium and MDF dust collection (SBFB-1500 spiral). 316L stainless 1.5 to 2.0 mm for powder coat oven exhaust at 200 C (SBAL-V at 316L plus SBSF-1525).

Crusader luxury caravan — Tullamarine VIC and the luxury caravan segment

Crusader Caravans at Tullamarine VIC produces the Crusader, Excaliber and Eagle Wing ranges as Australian luxury caravan specialists. The luxury segment runs lower volume than mainstream caravan production (Crusader at 30 to 60 units per week versus Jayco at 100 to 200) but higher per-unit value, more intensive joinery and cabinetry, more expensive composite construction and more aggressive paint specification.

The Crusader luxury process differs from production caravan in five ways. First, the composite construction uses higher-grade laminate (HPL solid surface, premium veneer, leather inlay, designer Formica) demanding tighter dust control in the joinery shop. Second, the paint specification includes multi-coat metallic effect and clearcoat finish demanding extended booth time and tighter humidity control. Third, the assembly tolerance is tighter with hand-fitted joinery and bespoke kitchen units. Fourth, the gas system specification includes premium appliances (Truma combi, Dometic high-end fridge) with higher commissioning tolerance. Fifth, the battery and electrical specification includes premium LiFePO4 banks with Victron Energy MultiPlus inverter and BMV battery monitor demanding higher commissioning standards.

Total Crusader Tullamarine installed HVAC supply runs 20 to 40 m3/s. The breakdown is 4 to 8 m3/s on panel and composite layup, 4 to 8 m3/s on isocyanate spray and powder coat (with extended booth time per unit), 6 to 10 m3/s on joinery and MDF (with tighter dust control), 3 to 5 m3/s on aluminium framework, 2 to 4 m3/s on chassis welding and steel, and the balance on assembly, LPG and battery commissioning.

Concept Caravans at Geelong VIC produces the Concept, Innovation and Innovative ranges as offroad luxury specialists, with similar HVAC scale and process mix to Crusader. Goldstream RV at Echuca VIC produces Voyager and Storm ranges with smaller HVAC scale (10 to 20 m3/s installed). The luxury caravan segment as a whole — Crusader, Concept, Goldstream, plus the boutique builders at Echuca and Geelong — represents 200 to 400 m3/s of installed HVAC capacity across the segment.

Camper trailer and offroad camper manufacturing — Cub, Eagle, MDC, Lifestyle, Track Trailer

Camper trailer and offroad camper manufacturing runs a slightly different ventilation envelope from caravan and motorhome production. The camper trailer typically uses heavier steel chassis fabrication, simpler interior fit-out (no full kitchen, no full bathroom, no extensive joinery), and the canvas or tent body avoids the composite layup process entirely.

Cub Campers at Sydney and Melbourne produces heritage offroad camper trailers across the Brumby, Stallion, Highline, Spacedock and Daintree ranges. The Cub process is dominated by steel chassis fabrication (welding fume capture, plasma cutting fume), aluminium framework fabrication (dust collection), powder coat on chassis and accessories, and canvas or tent body assembly (sewing, eyelets, zippers — minimal ventilation demand). Total HVAC load is 5 to 12 m3/s installed.

Eagle Camper Trailers at Mt Druitt NSW produces offroad campers with a similar process to Cub at smaller scale (3 to 8 m3/s installed). MDC Caravans at Geelong and Brisbane (Mobile Distributors Co) produces the Forbes, Pioneer and Off Road ranges as offroad caravan and camper trailer specialists. MDC's process is more caravan-like with composite layup, joinery and full paint specification — total HVAC load is 10 to 20 m3/s installed across the Geelong and Brisbane facilities.

Lifestyle Camper Trailers, Outback Touring, Australian-Made Trailer, Trakshak and SLT-AT Australian offroad represent the broader camper trailer segment. Total installed HVAC across the camper trailer segment is 50 to 100 m3/s installed across the cluster.

Track Trailer at Melbourne is a specialised offroad camper manufacturer focused on independent suspension and chassis design. The Track Trailer process is dominated by chassis fabrication with smaller body fit-out — total HVAC load is 3 to 8 m3/s installed.

Motorhome conversion — Trakka, Sunliner, Winnebago Industries Australia

Motorhome conversion runs a different production line from caravan or camper trailer manufacturing. The base vehicle (Mercedes Sprinter, VW Crafter, Iveco Daily, Fiat Ducato, Renault Master) arrives as a cab chassis or van and the motorhome converter installs the body, interior, electrical, plumbing, gas and HVAC over a 200 to 600 hour conversion sequence depending on motorhome class.

Trakka Motorhomes at Wyong NSW produces luxury motorhome conversions on Mercedes Sprinter and Volkswagen Crafter base vehicles. The Trakka process is a Class B (van conversion) and Class B+ (high-roof van) specialist with smaller production volume (5 to 15 units per week) and higher per-unit value than caravan production. Total HVAC load is 15 to 30 m3/s installed.

Sunliner Motorhomes at Newcastle NSW produces Australian-built motorhome conversions on Sprinter and Iveco Daily base vehicles across Class B and Class C ranges. Total HVAC load is 10 to 20 m3/s installed.

Winnebago Industries Australia at Toowoomba QLD produces Class A, Class C and Class B motorhomes plus the Trakka co-production line. Winnebago is Australia's largest motorhome converter at Toowoomba with multi-bay parallel production and 10 to 30 units per week peak throughput. Total HVAC load is 30 to 60 m3/s installed.

The motorhome conversion HVAC differs from caravan production in three ways. First, the cab chassis enters the paint, assembly and gas commissioning bays at full vehicle height (typically 3.0 to 3.5 m on Sprinter, 3.5 to 4.0 m on Class A converted Iveco Daily), demanding higher bay ceiling and higher exhaust riser placement than a caravan body. Second, the diesel engine of the base vehicle must be ventilated during in-bay operation — short-term diesel exhaust capture at the tailpipe through flexible coupling to a stack discharge above roof. Third, the heavy vehicle modification compliance per VSB6 layers on top of the caravan-side compliance per VSB14, demanding additional engineering certification on engine modification, brake system modification and load distribution.

Ductwork at Trakka, Sunliner and Winnebago Industries Australia follows the caravan plant material specification with the addition of 316L stainless on the in-bay diesel exhaust capture (CO and NO2 attack zinc) and dedicated ventilation on the engine commissioning area.

ADR 38 AS/NZS 5048 compliance and the vehicle-side regulatory regime

Australian caravan, RV, motorhome, camper trailer, pop-top and slide-on compliance runs through two parallel regulatory regimes that the build-shed PCBU must satisfy simultaneously. The vehicle-side regime governs the completed product (the caravan or motorhome that leaves the factory gate). The build-shed regime governs the workplace where the product is fabricated. The two regimes are administered by different agencies but the build-shed PCBU is the single accountable party.

The vehicle-side regulatory regime runs through Australian Design Rules (ADR) under the federal Motor Vehicle Standards Act administered by the Department of Infrastructure. ADR 38 governs trailer brake systems on caravans and camper trailers over 750 kg ATM (Aggregate Trailer Mass). ADR 79 governs vehicle emissions on motorhome and Class A diesel-powered units. ADR 80 governs vehicle braking. AS/NZS 5048 covers trailer general design including chassis, A-frame, drawbar, coupling, lighting and reflectors.

VSB14 — Vehicle Standards Bulletin 14 — National Code of Practice for Light Vehicle Construction and Modification covers the caravan and camper trailer body fit-out, electrical, plumbing and gas systems. Every caravan and camper trailer delivered to the market must satisfy VSB14 with documented engineering sign-off on the chassis modification, body construction, electrical compliance (12V/24V/240V), plumbing (freshwater, greywater, blackwater toilet, black and grey tank), and gas installation (per AS 5601 with AGCert).

VSB6 — Vehicle Standards Bulletin 6 — covers heavy vehicle modification including motorhome conversion on Iveco Daily, Mercedes Sprinter cab chassis and other heavy vehicle base. The motorhome converter (Trakka, Sunliner, Winnebago Industries Australia) must demonstrate VSB6 compliance with documented engineering sign-off on the body installation, chassis modification, brake system, suspension load and engine modification (if any).

State Vehicle Operating Standards (VOS) layer on top of the federal ADR and VSB regime. VicRoads in Victoria, Transport for NSW, Queensland TMR, SA DIT, WA DoT, Tasmania DSG and the NT DIPL each administer state-specific operating standards. The VIN plate, compliance plate and Vehicle Identification Number on the completed unit must satisfy both the federal ADR and the state VOS for the destination state.

The Caravan Industry Association of Australia (CIAA) is the peak national body coordinating member onboarding, compliance training and the annual Australian Caravan and Camping Show. State affiliates Caravan Industry Victoria (CIV), NSW Caravan and Camping Industry (CCIA), Caravanning Queensland, Caravanning South Australia, Caravan Industry WA, Caravanning Tasmania and Caravanning NT handle state-level engagement. The Recreational Vehicle Manufacturers Association (RVMA) covers a parallel member network with overlapping membership. The Federal Chamber of Automotive Industries (FCAI) handles vehicle-side coordination with the federal regulator. The Australian Caravan Club (ACC) and Touring Caravan and Motorhome Club represent owner-operator interests.

The ventilation envelope of the build shed is governed by the workplace safety regime — AS 4114.2, AS 1668.2, AS/NZS 60079, AS 3957, NFPA 484, NFPA 660, NFPA 86, AS 5601 (for gas commissioning), AS/NZS 1596 (for LPG storage). The build shed PCBU must demonstrate dual compliance with both regulatory regimes during routine and incident-triggered inspections by state WorkSafe regulators (WorkSafe VIC, SafeWork NSW, Workplace Health and Safety QLD, WorkSafe WA, SafeWork SA, WorkSafe TAS and NT WorkSafe) and the federal Department of Infrastructure for ADR audit.

Assembly line ventilation — chassis-up build and final QC

The assembly bay is the longest single ventilation zone in a caravan plant. Chassis-up build sequence: floor pan installation, wall panel attachment, roof panel attachment, window and door installation, furniture install, kitchen install, bathroom install, bedroom install, lounge install, stove, fridge, hot water service, HVAC test, electrical, plumbing, gas commissioning. Jayco production line at Dandenong runs 100 to 200 units per week peak across multiple parallel bays of 200 to 500 m length each. Avida at Emu Plains runs 30 to 80 units per week across shorter parallel bays.

The assembly bay ventilation is general dilution at 4 to 6 ACH with localised solvent extract at glue and sealant stations. Silicone Sikaflex (252, 521 UV) VOC release during application is significant (acetic acid release during cure, plus the carrier solvent VOC). PU foam expansion releases residual MDI isocyanate (the 0.005 ppm WES target applies). Contact cement (toluene 50 ppm, MEK 200 ppm) releases solvent at every adhesive station. Polyester and vinylester resin touch-up at body repair stations releases styrene.

The make-up air for the assembly bay must accommodate the open doors during chassis movement between bays plus the localised solvent extract. Typical make-up air rate is 6 to 12 m3/s per bay on a Jayco-scale operation, with the supply train including a heating coil for winter make-up at 5 to 15 C ambient outdoor temperature and a cooling coil for summer at 30 to 40 C ambient.

Final QC includes road test (drive-around at the test track for brake, lighting, electrical, structural noise), water test (rain simulator for leak detection), electrical test (12V/24V/240V circuit verification, RCD test, earth leakage test), gas test (pressure decay leak test plus AGCert sign-off), road worthy certificate, ADR compliance plate and VIN plate stamping. The QC area ventilation runs at 4 to 6 ACH general dilution plus dedicated extract at the gas test station and the water test enclosure.

Ductwork on the assembly bay: galvanised 0.8 to 1.2 mm rectangular on SBAL-V at GAL for general supply, 316L stainless 1.5 mm on the solvent and adhesive extract (SBAL-V at 316L), galvanised 1.0 mm on the QC return air trunks (SBAL-V at GAL).

Warehouse, shipping and pre-delivery storage ventilation

Caravan, motorhome and camper trailer manufacturing carries a significant storage and shipping load. Jayco, Avida, Trakka, Sunliner, Winnebago Industries Australia and the larger builders operate dedicated warehouse buildings for raw material (aluminium plate, fibreglass roving, resin drums, paint, hardware, MDF panels, structural extrusion, LPG cylinders), parts (appliances awaiting installation, batteries, electronics, joinery materials), finished units awaiting dealer delivery and used trade-in units awaiting refurbishment.

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. LPG cylinder bulk storage runs at 6 to 12 ACH continuous per AS/NZS 1596.

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). Pre-delivery storage of completed units typically runs outdoor under shade structure rather than full warehouse, with only the inventory office requiring full HVAC. Total shipping bay HVAC load is 1 to 3 m3/s installed.

Used trade-in refurbishment is a growing segment at the larger CIAA member shops. The trade-in unit arrives at the factory with unknown condition, age and history. Refurbishment runs through a parallel light-touch process — exterior wash, joinery repair, electrical and gas re-certification, paint touch-up, new flooring and soft furnishings. The refurbishment bay ventilation runs at 4 to 6 ACH general dilution plus localised extract at solvent and paint stations.

Marine corrosion and humidity — coastal NSW and QLD builders

Coastal caravan and motorhome plants at Emu Plains NSW (close to the Sydney coastal influence), Wyong NSW, Newcastle NSW and the Brisbane and Toowoomba QLD cluster experience varying degrees of chloride-laden marine atmosphere. Avida at Emu Plains is 60 km inland from the Sydney coast but the prevailing easterly weather carries enough chloride for low-grade corrosion on galvanised duct over 10 to 15 years. Trakka at Wyong NSW is 10 km inland from the Central Coast — moderate chloride exposure with galvanised duct service life of 8 to 12 years. Sunliner at Newcastle NSW is 5 km inland from the Newcastle coast — high chloride exposure with galvanised service life of 5 to 8 years.

Material selection accommodates the coastal 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 18 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.

Inland builders at Dandenong VIC, Tullamarine VIC, Geelong VIC, Echuca VIC, Frankston VIC, Campbellfield VIC and Toowoomba QLD experience minimal chloride exposure. Galvanised duct service life is 20+ years inland.

Acoustic and NC requirement across caravan plant zones

The acoustic envelope across an Australian caravan plant varies from NC-30 in the CAD room and engineering office through NC-35 in the administration and dealer showroom, NC-45 in the production and quality process, to NC-50 in the dust collection plant room and powder coat oven enclosure. 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 layup room ventilation (30 to 80 kW each), the dust collection fans (15 to 50 kW) and the spray booth exhaust fans (20 to 60 kW) 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 caravan 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 in caravan plants

Caravan and RV manufacturers carry a high density of AS/NZS 60079 hazardous areas. A typical Jayco-scale operation has five to eight distinct Zone 1 or Zone 2 areas (spray booth interior Zone 1, booth surrounds Zone 2, resin store Zone 2, paint mix room Zone 1, LPG cylinder reception Zone 1, Li-ion battery commissioning bay Zone 2, powder coat cure oven Zone 1, vehicle fuel commissioning area Zone 1) plus three to six Zone 22 dust areas (around aluminium and MDF dust collectors). 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 paint system, a new battery bank, a new LPG appliance) triggers a hazardous area drawing revision.

The caravan plant's process safety case relies on the hazardous area drawing being correct. State WorkSafe regulators 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 caravan plant process safety audits.

NCC, structural and seismic compliance

Caravan plant buildings are typically National Construction Code (NCC) Class 8 industrial occupancy with Class 7b storage component and Class 9b assembly component on the dealer showroom side. Fire resistance ratings (FRL) range from 60/60/60 on internal partitions through 120/120/120 on bake-out rooms, resin stores, LPG cylinder reception and Li-ion battery commissioning bays. 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 (caravan plants at Dandenong, Emu Plains, Toowoomba face moderate wind exposure per Region A wind zone; coastal builders at Newcastle and Wyong face higher exposure per Region A2; QLD coastal at Toowoomba face cyclone exposure per Region B), part 4 covers earthquake load, part 5 covers marine load (relevant for coastal sheds). 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 caravan and RV manufacturer projects

SBKJ duct fabrication machinery covers the full range of caravan and RV manufacturer requirements, from small camper trailer specialist shops through to Jayco-scale multi-bay production lines. Five SBKJ machine families are sized and configured for caravan plant applications.

SBAL-V auto duct line for galvanised general HVAC supply. Our flagship rectangular duct line, configured for caravan plant 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 caravan plant duct sizes (300 to 1,200 mm). SBAL-V auto duct line specification.

SBAL-V stainless variant for fibreglass, isocyanate, LPG and Li-ion battery. 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, LPG cylinder reception ventilation, Li-ion battery commissioning bay exhaust and powder coat cure oven exhaust at 200 C.

SBAL-III three-line variant. A reduced-footprint variant of the SBAL-V for smaller caravan and camper trailer operations. Suitable for builders running fewer than 500 units 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 aluminium dust collection, MDF and timber dust collection, return-air trunks, powder coat overspray collection, composite carbon fibre dust extraction and connection to the abatement system. 100 to 1,500 mm diameter range covers everything from joinery shop dust collection through to multi-bay parallel return-air discharge. Spiral seam construction reduces leakage to under 1 percent at 1,000 Pa for SMACNA leakage class 6 — important for styrene-laden, isocyanate-laden and HF-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, smoke-spill 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 over 2 hours. SB-ZF1500 covers a similar envelope at slightly reduced size and capital cost. Both machines used on the heavy-gauge sections at the powder coat cure oven exhaust, post-cure bake oven, autoclave skin and engine exhaust stack base on motorhome conversion lines.

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 dealer 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 caravan and camper trailer operations or for refurbishment 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).

SB-ZF1500 stitchwelder. Heavy-gauge stitchwelder at compact footprint for smaller caravan and camper trailer plant scale. Handles 1.2 to 1.8 mm galvanised or stainless with continuous seam welding at 250 C smoke spill rating.

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 caravan and RV manufacturer ventilation runs across eighteen primary references. AS 4114.2 governs spray booth construction and ventilation. AS 1668.2 governs general mechanical ventilation. AS 1668.1 governs smoke-spill 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/NZS 1596 covers LPG storage. AS 5601 covers gas installation. 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 framework and chassis), NFPA 660 (consolidated combustible dust in 2025 including MDF and wood dust), NFPA 86 (ovens including powder coat cure at 200 C, paint bake at 60 C and autoclave composite cure), NFPA 30 (flammable liquids overlay), NFPA 13 (sprinkler design) and NFPA 70 NEC (electrical hazardous area).

The vehicle-side compliance regime adds ADR (Australian Design Rules) under the federal Motor Vehicle Standards Act (ADR 38 trailer brake, ADR 79 emissions, ADR 80 braking, AS/NZS 5048 trailer general design), VSB14 light vehicle modification, VSB6 heavy vehicle modification and state Vehicle Operating Standards (VOS).

The Australian industry body framework runs through the Caravan Industry Association of Australia (CIAA) as the peak national body, state affiliates Caravan Industry Victoria (CIV), NSW Caravan and Camping Industry (CCIA), Caravanning Queensland, Caravanning South Australia, Caravan Industry WA, Caravanning Tasmania and Caravanning NT, the Recreational Vehicle Manufacturers Association (RVMA), the Federal Chamber of Automotive Industries (FCAI), the Truck Industry Council (TIC) for heavy vehicle modification, the Australian Caravan Club (ACC) and the Touring Caravan and Motorhome Club.

Workplace exposure standards and WES summary

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

Styrene: 50 ppm TWA, 100 ppm STEL. The killer chemical of fibreglass polyester and vinylester resin composite work.
Polyurethane TDI and MDI isocyanate: 0.005 ppm STEL. The killer of caravan and motorhome topcoat — endocrine disruption and occupational asthma. Also released from PUR spray foam insulation and structural panel cure.
Epoxy resin: Skin sensitiser, allergic contact dermatitis, carpal tunnel syndrome. Used in panel layup, structural bonding and selected luxury composite work.
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).
Solvent VOC: Acetone 250 ppm, IPA 400 ppm, MEK 200 ppm, ethyl acetate 200 ppm, toluene 50 ppm, xylene 50 ppm, MIBK 50 ppm. Resin solvent, gel coat thinner, panel adhesive, cleaning solvent, contact cement, edge banding.
Respirable composite fibre dust: 5 mg/m3 inhalable. Cured composite sanding, drilling, machining — carbon fibre, glass fibre, aramid Kevlar.
Formaldehyde: 1 ppm STEL. From MDF, chipboard, laminate, urea-formaldehyde and phenol-formaldehyde adhesive, panel layup, joiner panels, PVC laminate, Formica, HPL, ABS thermoformed plastic, vacuum-formed plastic, stranded board, glass wool, rock wool, polystyrene EPS and XPS, PIR and PUR foam, Aerocel and Armaflex elastomer foam.
Respirable particulate: 5 mg/m3 respirable, 10 mg/m3 inhalable. Gel coat, sanding, polishing, vacuum-formed plastic trimming, wood dust, paint primer dust, panel offcut, laminate offcut.
VOC general (paint, thinner, adhesive): Silicone Sikaflex, PU foam expansion, epoxy, polyester, vinylester resin, MDI urethane PUR.
DCM methylene chloride: 50 ppm STEL. Paint stripper banned 2023 with benzyl alcohol replacement or NMP biodegradable alternative.
Methane CH4: 1.25 percent LEL. LPG cylinder reception, decanting, on-vehicle commissioning, leak test.
Hydrogen H2: 25 percent LEL. Lead-acid battery off-gas during initial charge, Li-ion thermal runaway, aluminium plus water reactivity.
Hydrogen fluoride HF: 1.8 ppm STEL. Li-ion thermal runaway, aluminium pre-paint etch.
Chromium VI: 0.05 mg/m3 STEL. Stainless steel rig and hardware fabrication.
Nickel: 0.1 mg/m3 respirable. Stainless steel weld and grind.
Carbon monoxide (CO): 30 ppm TWA. LPG forklift, motorhome engine commissioning, gas appliance commissioning.
Manganese respirable: 0.2 mg/m3. Welding fume from steel chassis and aluminium framework.
Iron oxide: 5 mg/m3. Steel chassis weld fume.

Every LEV system in a caravan plant must be designed to maintain operator breathing-zone exposure under the relevant WES with adequate margin. Most CIAA 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 caravan plant fit-out run 12 to 16 weeks from purchase order to factory acceptance test, plus 4 to 6 weeks ocean freight to Melbourne, Sydney, Brisbane, 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 is geographically optimal for the Dandenong cluster (30 minutes by road), the Tullamarine cluster (40 minutes by road), the Geelong cluster (60 minutes by road), the Frankston and Campbellfield builders (45 to 60 minutes by road) and the Echuca cluster (3 hours by road). For Avida Emu Plains NSW (rail or truck from Box Hill North in 16 to 24 hours), for Trakka Wyong and Sunliner Newcastle NSW (similar logistics), for Winnebago Industries Australia Toowoomba QLD (truck from Box Hill North in 24 to 36 hours), the Box Hill North office handles project management, engineering support and field service dispatch.

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 a primary venue for the Australian caravan industry HVAC supply chain meeting in person. Visit the SBKJ stand at ARBS 2026 to scope a caravan plant fit-out with the engineering team.

Cross-sector applications

Many of the engineering principles in caravan and RV manufacturer 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:

Marine yacht boatbuilder HVAC duct guide — fibreglass styrene, isocyanate spray, NFPA 484 aluminium and engine commissioning ventilation for Riviera Coomera, Maritimo, SilverYachts Henderson WA.
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.
Bus, truck and coach manufacturing HVAC duct guide — heavy vehicle conversion, body building and paint booth ventilation for the Australian commercial vehicle sector.
Powder coat line HVAC duct guide — pretreatment, drying oven, electrostatic spray and 200 C cure oven exhaust for powder coating shops.

For Australian caravan plant 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 gel coat and panel layup in caravan production?

Layered LEV at every layup table or panel press (slot canopy hood at 0.5 to 1.0 m/s capture velocity) plus general ventilation at 4 to 6 ACH dilutes residual vapour. Closed-mould VARIM cuts 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 caravan manufacturers running aluminium framework and chassis?

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 caravan 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 luxury caravan and Class A motorhome, cross-draft 0.5 to 0.6 m/s for production volume. 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 MDF and joinery dust handled in caravan cabinetry fabrication?

Three coexisting hazards: respirable wood dust at WES 5 mg/m3, formaldehyde at 1 ppm STEL, NFPA 660 combustible dust at Kst 100 to 200 bar.m/s. Local extraction at 18 to 23 m/s transport velocity. Cyclonic pre-separator plus bag house with explosion vent, rotary airlock isolation. Bonding to less than 10 ohms. Galvanised 1.2 mm with conductive sealant.

How is the lithium-ion LiFePO4 battery commissioning bay ventilated?

Routine commissioning generates negligible gas — general dilution 4 to 6 ACH. Thermal runaway releases H2 at 25 percent LEL, HF at 1.8 ppm STEL, CO, organic carbonate vapour. AS/NZS 60079 Zone 2 classification. Emergency-power extract fan at 4 to 8 ACH. Fixed gas detection on H2, HF, CO. Class D extinguishing media. Ductwork 316L stainless because HF attacks galvanised within hours.

What materials are specified for Australian caravan plant 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, LPG cylinder reception, Li-ion battery commissioning bay (SBAL-V at 316L). Galvanised 1.2 mm with conductive sealant for aluminium and MDF dust collection (SBFB-1500 spiral). 316L stainless 1.5 to 2.0 mm for powder coat cure oven exhaust at 200 C.

What air volumes for a mid-size Australian caravan manufacturer?

15 to 30 m3/s total supply across the facility. Panel layup 4 to 8 m3/s. Spray booth 4 to 8 m3/s per booth. Joinery and MDF 8 to 15 m3/s. Aluminium dust 4 to 8 m3/s. Chassis welding 2 to 4 m3/s. LPG reception 1 to 2 m3/s. Li-ion battery 1 to 2 m3/s. Jayco Dandenong (Australia's biggest) operates 80 to 150 m3/s. Avida Emu Plains (second biggest) operates 40 to 80 m3/s.

How is LPG cylinder reception ventilated in caravan plants?

AS/NZS 60079 Zone 1 within 1 m of cylinder valves, Zone 2 within 3 m. AS/NZS 1596 LPG storage. AS 5601 gas installation. AGCert certification mandatory. 6 to 12 ACH continuous. Low-level extract grilles (LPG denser than air at 1.55 SG). Fixed CH4 detection at 25 percent LEL warning, 50 percent LEL action. Spark-free electrical. 316L stainless duct.

What standards govern Australian caravan manufacturer ventilation?

AS 4114.2 spray booth, AS 1668.2 general ventilation, AS 4254 duct construction, AS/NZS 60079 hazardous gas, AS 3957 dust hazard, NFPA 484 combustible metal, NFPA 660 (2025) combustible dust, NFPA 86 ovens, AS 5601 gas, AS/NZS 1596 LPG. Vehicle side: ADR 38, ADR 79, ADR 80, AS/NZS 5048, VSB14, VSB6. CIAA Caravan Industry Association of Australia is peak body. RVMA covers parallel manufacturer network.

What SBKJ machine model for an Australian caravan manufacturer 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 round duct (10 to 12 weeks). SBSF-1525 stitchwelder for heavy-gauge fire-rated and 200 C powder coat oven. SBAL-III for smaller builders. SBPC1500 plasma for custom fittings. SBLR-600 louvre former for showroom and acoustic silencers. Add 4 to 6 weeks ocean freight to Australian ports.

Get an SBKJ caravan plant duct quote →

Get in touch with the SBKJ engineering team

Spec'ing duct fabrication for a caravan, RV, motorhome, camper trailer, pop-top or slide-on manufacturer fit-out at Dandenong, Tullamarine, Geelong, Echuca, Frankston, Campbellfield, Emu Plains, Wyong NSW, Newcastle NSW, Toowoomba QLD or anywhere else in Australia? An SBKJ mechanical engineer replies within 12 hours — not a salesperson. We will scope your fit-out from the CIAA 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

12-hour reply

Spec'ing duct fabrication for an Australian caravan, RV, motorhome, camper trailer, pop-top or slide-on manufacturer fit-out? An SBKJ mechanical engineer replies within 12 hours — not a salesperson.

Ask an engineer