Why drone manufacturing HVAC is not the same as either composite or electronics work
A drone, uncrewed aerial vehicle or counter-UAS facility is, on first inspection, an unusual mix of two unrelated manufacturing disciplines under a single roof. One end of the shop floor is a composite manufacturing operation — carbon fibre prepreg laid up by hand on heated tools, vacuum bagged, cured at 180 degrees Celsius in an autoclave or out-of-autoclave oven, then trimmed, drilled and finished. The other end of the shop floor is an aerospace-grade electronics assembly hall — autopilots, flight controllers, inertial measurement units, radio links, motor controllers and the high-energy lithium-ion battery packs that power the platform. Between those two extremes sits the test, calibration and final integration scope. Each of the three zones has incompatible HVAC requirements — and the unifying engineering challenge is keeping them physically and atmospherically separated while still moving parts efficiently between them.
The Australian drone and uncrewed systems industry has expanded sharply over the past five years. DroneShield is delivering counter-UAS detection and disruption electronics into more than thirty international customers from Sydney. Boeing Defence Australia is in series production of the MQ-28A Ghost Bat at the Wellcamp facility in Queensland. Innovaero in Bayswater Western Australia has commercialised the Strix loyal wingman and the AIM-9X Marauder. AMSL Aero is flight-testing the Vertiia eVTOL at Bankstown. Carbonix is fielding long-range VTOL platforms. Anduril Australia is producing the Ghost Shark XL-UUV in Adelaide. The Defence Science and Technology Group at Edinburgh South Australia and Fishermans Bend Victoria runs research, prototype build and integration capability for the wider Pillar 2 programme under AUKUS. Each of these operators sits inside a converted industrial building or a purpose-built facility, and each of them eventually has to commission HVAC ductwork that satisfies competing process, regulatory and survivability constraints.
SBKJ Group operates from Box Hill North Victoria and supplies the auto duct lines, spiral tubeformers and stitchwelders that fabricate the bulk of the lockformed and stainless steel ductwork in this sector. We field engineering questions from contractors and prime integrators on what a drone facility actually needs — and the questions are different from those that arise on a general aviation MRO hangar, on a composite wind blade plant or on a generic electronics assembly line. This guide is a working reference for those questions.
The four dimensions that make drone manufacturing HVAC distinct can be summarised in advance. The first is the small batch but high product variability of the work — a single facility might produce six different airframes, three composite material systems and five propulsion configurations in a year, and the HVAC has to flex across all of them without single-product optimisation. The second is the cleanliness conflict — carbon fibre dust is conductive, and any loose fibre that escapes the layup or machining hall and migrates into the adjacent electronics assembly area is a latent short-circuit risk on energised avionics. The third is the lithium-ion battery hazard — drone batteries are some of the highest energy-density chemistries deployed in commercial production, and abuse-test cells have to contain a worst-case thermal runaway without injury and without facility loss. The fourth is the classification and export-control overlay — counter-UAS systems and any military uncrewed work are governed by the Defence Trade Controls Act 2012, by the Defence and Strategic Goods List and, on bilateral programmes, by US ITAR. The HVAC contractor needs to operate inside that compliance envelope.
The Australian drone and uncrewed systems industrial base
Before specifying HVAC, it pays to understand the customer base. The Australian drone and uncrewed systems industry is not a single sector — it is a constellation of platform builders, electronics integrators, composite fabricators, software companies and counter-UAS operators clustered around a few major capital cities. The HVAC duct demand differs significantly between segments.
Counter-UAS detection and disruption
DroneShield Limited (ASX:DRO) is the most prominent name in the segment. Headquartered in Sydney with manufacturing and engineering facilities expanded over 2024 and 2025, the company designs and produces RF-based drone detection sensors, fixed-site and on-the-move counter-UAS platforms, and the spectrum analytics software that runs the system. The customer base spans defence ministries, special forces, civil aviation authorities and critical infrastructure operators across more than thirty countries. The HVAC scope is concentrated in the electronics assembly hall, the avionics integration cell, the RF anechoic chamber for antenna and system pattern testing, and the calibration laboratory.
Saab Australia delivers the Giraffe 1X and Giraffe 4A counter-UAS radar from Adelaide and integrates radar with shooter cues for layered counter-UAS engagements. Penten in Canberra covers the cyber overlay on counter-UAS data links and the protective electronics that hardens defence networks against drone-borne information collection. Skyborne Technologies and Stealth Technologies sit alongside as specialist counter-drone and autonomous-defence-vehicle suppliers. Each of these programmes carries some RF-shielded test capability and some classified bench work, both of which drive specific HVAC duct construction requirements.
Loyal wingman and combat uncrewed
The MQ-28A Ghost Bat is Boeing Defence Australia's collaborative combat aircraft, in series production at the Wellcamp Aerospace Precinct adjacent to Toowoomba Wellcamp Airport in Queensland. The aircraft is the first locally designed and produced combat air vehicle to enter production in Australia in more than five decades and is being delivered to the Royal Australian Air Force under Project Air 7003. The composite content is sourced from Quickstep Holdings (ASX:QHL) at Bankstown New South Wales and at Geelong Victoria — the same operator that produces composite F-35 components for Lockheed Martin. Marand Precision Engineering at Moorabbin Victoria delivers the F-35 vertical tail and other precision aerospace assemblies, and is part of the wider Australian aerospace supply chain that may support MQ-28A subassemblies. The HVAC duct demand on this programme is concentrated in the composite layup hall, the autoclave hall and the final integration floor at Wellcamp, with electronics integration cells co-located inside the production facility.
BAE Systems Australia and Innovaero are partnering on the Strix loyal wingman at the Bayswater Western Australia facility, with AIM-9X Marauder also being commercialised through Innovaero. The HVAC scope mirrors the Ghost Bat programme — composite primary structure, electronics integration, propulsion test, battery integration and final assembly.
Long-range VTOL and eVTOL
AMSL Aero is developing the Vertiia eVTOL at Bankstown New South Wales. Vertiia is a hydrogen-electric vertical take-off and landing aircraft intended for medical and logistics transport. The certification pathway adds an additional regulatory overlay because eVTOL is treated by CASA and EASA as a separate aircraft category from conventional fixed-wing or rotorcraft. The HVAC scope at Bankstown spans composite layup, electronics integration, battery testing and final assembly, with a hydrogen handling overlay that brings additional AS/NZS 60079 hazardous-area classification to the fuel system test bay.
Carbonix designs long-range fixed-wing VTOL UAS for survey, inspection and surveillance from Sydney. Volans-i and other smaller operators sit in similar segments. The HVAC demand for these programmes is concentrated in the composite layup hall and the avionics integration cell, with a smaller battery test footprint than the larger combat or eVTOL programmes.
Loitering munition and small drone
DefendTex in Melbourne produces the Drone40 loitering munition, a 40 mm grenade-launched system. Production scope is mixed-mode — small composite or polymer airframe, electronics integration, energetics handling and final assembly. The HVAC scope is smaller in floor area than the larger platform builders but includes a dedicated energetics handling area that brings AS/NZS 60079 Zone 1 classification to the ductwork.
Uncrewed undersea
Anduril Australia is producing the Ghost Shark XL-UUV (extra-large uncrewed undersea vehicle) in Adelaide for the Royal Australian Navy. The Ghost Shark is conceptually an uncrewed submarine and the HVAC scope is closer to a marine vehicle build than to an aerial vehicle. Composite content, electronics, battery testing and final integration still apply but the marine environment adds chloride exposure to the duct material selection and adds pressure hull leak testing to the final integration test schedule.
Surveillance and ISR
Insitu Pacific, a Boeing subsidiary based in Canberra and Brisbane, supports the ScanEagle and RQ-21A Blackjack uncrewed reconnaissance platforms for Australian and allied users. Northrop Grumman Australia supports the MQ-4C Triton and MC-55A Peregrine programmes through Australian-based sustainment infrastructure. Lockheed Martin Australia covers a wide span of platforms including selected uncrewed support. These programmes are operated through hangar and integration facilities that overlap the wider aviation MRO sector, and many of the HVAC considerations on those scopes are covered in the companion guide on aviation MRO hangar and paint shop HVAC.
Research, prototyping and integration
The Defence Science and Technology Group operates major campuses at Edinburgh South Australia (co-located with RAAF Edinburgh) and at Fishermans Bend Victoria. Both campuses contain classified laboratories, prototype build halls and test environments for uncrewed systems work under Pillar 2 of AUKUS. The HVAC demand profile at DSTG facilities is denser than commercial drone manufacturers per square metre — laboratories require tighter environmental stability, classified zones require TEMPEST emanation control and prototype build halls flex across multiple platform technologies.
Reaction Engines Australia covers hypersonics, an adjacent unmanned-systems technology category. AOS Group Defence provides aerospace engineering services with Loyal Wingman programme involvement. Asension Australia, HEICO Australia at Tugun Queensland, Lovitt Technologies Australia in Melbourne, Ferra Engineering at Brisbane and Levett Engineering at Adelaide all contribute precision aerospace components into uncrewed and crewed programmes. BAE Maritime and Land Systems Adelaide overlap with the unmanned and counter-UAS scope through shared test infrastructure. The Robotics Australia Group industry body convenes the wider commercial uncrewed-systems community.
The standards stack — what drone manufacturing HVAC is engineered against
Drone, UAV and counter-UAS manufacturing HVAC is designed against an overlapping stack of civilian, aerospace, electronics and battery-safety standards. The stack is hierarchical: the most demanding overlay governs in any given location.
Civilian Australian baseline
AS 1668.2 — The use of ventilation and airconditioning in buildings, Mechanical ventilation in buildings — sets the minimum outside-air rate, contaminant control framework and general dilution ventilation methodology for any Australian workplace. AS 4254.1 and AS 4254.2 — Ductwork for air-handling systems in buildings — set the construction, sealing class, support and access framework for HVAC duct in Australia. AS 1530.4 governs fire-resistant duct construction and applies wherever duct penetrates a fire-resistance level boundary. AS 1668.1 governs the use of mechanical ventilation for fire and smoke control. AS 1170.4 governs seismic restraint. These standards remain active on every Australian drone facility regardless of classification — they are the baseline that the aerospace and battery overlays sit on top of.
Aerospace electronics workmanship
IPC-A-610 Class 3 is the industry consensus standard for electronic assembly acceptability in aerospace and military electronics. The standard sets workmanship criteria for soldering, conformal coating, mechanical assembly and through-hole and surface-mount technology. Class 3 represents the most stringent acceptability level — used wherever continued performance under harsh conditions is critical and downtime cannot be tolerated. The HVAC connection is that Class 3 work is performed in an ESD-controlled, humidity-controlled, particulate-controlled environment. IPC-J-STD-001 is the companion soldering standard.
IEC 61340-5-1 is the ESD Control Programme standard for electronics manufacturing. The standard requires a defined ESD Protected Area (EPA) with grounding, personnel garments, packaging and humidity control. The HVAC contribution is humidity stability — ESD susceptibility in unprotected electronics rises sharply below 30 per cent relative humidity. Avionics assembly is held at 45 ±5 per cent RH and 22 ±2 degrees Celsius to manage ESD risk and human comfort simultaneously.
ISO 14644 — Cleanrooms and associated controlled environments — sets the cleanliness class system used to specify composite layup rooms and electronics assembly cells. ISO Class 8 is the typical baseline for aerospace primary structure prepreg layup. ISO Class 7 is used for the most sensitive avionics integration cells.
ISO 17025 is the general requirements for the competence of testing and calibration laboratories. In-house calibration laboratories for inertial measurement units, magnetometers and pressure sensors at drone manufacturing facilities are typically accredited to ISO 17025 through NATA (National Association of Testing Authorities) in Australia.
Battery safety
NFPA 855 is the US Standard for the Installation of Stationary Energy Storage Systems and is the most-cited reference internationally for lithium-ion battery facility design. AS/NZS 5139 is the Australian Standard for Electrical installations — Safety of battery systems for use with power conversion equipment, applying particularly to ESS scope. Both documents are referenced in drone-manufacturing battery test environments because the lithium chemistry, the failure modes and the engineering controls are largely identical between drone-scale and grid-scale.
NFPA 484 was the historical reference for combustible metals (magnesium, aluminium, titanium, zirconium and related metals). NFPA has now consolidated combustible-dust standards into NFPA 660 — Standard for Combustible Dusts and Particulate Solids. AS 3957 sets the Australian dust hazard analysis framework. Both documents apply wherever drone airframe machining generates respirable metallic dust.
AS/NZS 60079 series governs hazardous-area equipment in flammable atmospheres. Battery test chambers handling vented electrolyte vapour, hydrogen handling in eVTOL fuel cell test, energetics handling in loitering munition production and resin solvent handling in composite shops can all attract Zone 1 or Zone 2 classification under AS/NZS 60079.
AS 1940 — The storage and handling of flammable and combustible liquids — sets the framework for storage and handling of composite resin solvents, fuels and process chemicals.
Workplace exposure standards
Safe Work Australia publishes the Workplace Exposure Standards for Airborne Contaminants. The standards that bind on drone manufacturing HVAC include: styrene 50 ppm 8-hour TWA (a baseline for open-mould composite layup, though most drone composite work uses prepreg systems with much lower styrene release), methylene diphenyl diisocyanate (MDI) 0.005 ppm STEL on polyurethane foam systems, respirable carbon fibre dust 5 mg per cubic metre on machining and trim operations, lead-free solder fume 0.1 mg per cubic metre at the operator breathing zone, total isocyanate 0.02 mg per cubic metre on polyurethane coatings. The HVAC source-capture system has to achieve breathing-zone concentrations below the relevant exposure standard.
Regulatory and operational overlays
Civil Aviation Safety Regulation Part 101 — Unmanned aircraft and rockets — administered by the Civil Aviation Safety Authority (CASA), covers operator certification, airworthiness, registration and operational rules for civil remotely piloted aircraft systems in Australian airspace. ASA-5000 is the suite of Defence Aviation Safety Regulations issued by the Defence Aviation Authority for ADF military aircraft, including military uncrewed systems. The two pathways are distinct and a platform may need certification under both for dual-use operation.
Defence Trade Controls Act 2012, administered by Defence Export Controls within the Department of Defence, regulates the export, brokering and publication of defence and dual-use technology under the Defence and Strategic Goods List (DSGL). Counter-UAS RF disruption equipment and military uncrewed systems are typically captured by the DSGL. On bilateral programmes the US International Traffic in Arms Regulations (ITAR) may also apply, particularly on programmes with US prime contractors.
US FAA Part 107 covers civil drone operation in US airspace and is relevant for any Australian-built drone exported to the United States. EASA UAS Regulation 2019/947 and 2019/945 cover the European pathway. Australian Defence Standards in the DEF (AUST) 5000 series cover defence-specific design and qualification requirements that overlay commercial standards.
NATA accreditation
The National Association of Testing Authorities (NATA) accredits testing and calibration laboratories in Australia. NATA accreditation of an in-house calibration laboratory is a formal third-party validation of competence against ISO 17025. Drone manufacturers seeking to maintain their own calibration capability — typically for inertial measurement units, magnetometers, pressure sensors and motor balancing — operate inside a NATA accreditation envelope. The HVAC contribution is environmental stability validated through NATA-accepted measurement.
Composite layup room HVAC — the most demanding zone
The carbon fibre and epoxy prepreg layup room is the most HVAC-demanding zone in a typical drone manufacturing facility. The specification has to deliver four properties simultaneously: ISO 14644 Class 8 cleanliness, 22 ±2 degrees Celsius temperature stability with very tight short-term band, 50 ±5 per cent relative humidity for resin tack and to prevent moisture pick-up by the prepreg, and very low surface velocity below 0.25 m/s at the layup bench to avoid disturbing dry fabric and stirring loose carbon fibre off the bench surface.
ISO 14644 Class 8 cleanliness — 3.5 million particles per cubic metre at 0.5 microns, equivalent to the legacy Class 100,000 — is achieved through filtered supply air, positive pressure relative to surrounding spaces, controlled gowning protocols and disciplined housekeeping. The supply ductwork to the layup room is typically 304L stainless steel internally polished, or epoxy-coated galvanised steel, with low-leakage TDF flange connections. Galvanised duct with conventional butyl gasket tape sealant is not appropriate for a Class 8 layup room because the gasket releases particulate over time and shortens the time-to-clean cycle.
The temperature and humidity stability bands are tighter than typical commercial HVAC and require a dedicated air handling unit with chilled water cooling, hot water reheat (or electric reheat for smaller cells), and either a steam humidifier or a wet-cell evaporative humidifier sized for the latent load. Direct expansion split systems and conventional VAV systems do not deliver the stability required without dedicated tuning and additional buffer volume.
The low-surface-velocity requirement — below 0.25 m/s at the layup bench — drives the diffuser specification. Ceiling-mounted fabric sock diffusers or large-area perforated panel diffusers are the common choice. Standard four-way blow ceiling diffusers create local high-velocity zones that disturb dry carbon fabric and stir dust off the bench surface. The supply ductwork to the diffusers should be sized for low velocity — typically 5 to 7 m/s in main runs, 3 to 4 m/s in branch runs to the diffusers — to maintain a quiet, stable supply pattern.
Prepreg out-life management is the operational driver for temperature stability. Most aerospace-grade prepreg systems are qualified for 30 days out-of-freezer at 21 degrees Celsius. Every degree above 21 degrees Celsius accelerates resin advancement and shortens qualified out-life. A single HVAC failure event that pushes the layup room above 24 degrees Celsius for several hours can void the qualified out-life on every roll of prepreg in the room — and on a busy layup floor that scrap cost can run to several hundred thousand Australian dollars. The HVAC reliability target reflects this risk: redundant chilled water, dual compressors on the chiller, hot standby on the supply fan and a 30-minute hold time on the back-up generator. Many drone composite layup rooms also include a separate temperature monitoring system reporting to facility management with email alarming on excursion.
SBKJ recommends the SBAL-V auto duct line for the supply leg of the layup room. The SBAL-V runs galvanised coil at up to 16 metres per minute through the line with 87 kW total installed power, accepts coil thickness 0.5 mm to 1.5 mm and coil width up to 1500 mm. The galvanised duct is internally coated with a clean-room-grade epoxy paint to satisfy ISO 8 cleanliness. For the resin chemical fume return we specify 304L stainless steel supplied through the SBAL-III line (14 m/min, 15.7 kW installed power) and stitchwelded through the SBSF-1525 stitchwelder (2.5 kW) to seal longitudinal seams to a near-zero leakage class.
Autoclave hall HVAC
Drone composite primary structure cure is performed in an autoclave for the highest-load components (typically the structural wing and fuselage parts on combat and long-range UAS) or in an out-of-autoclave (OOA) oven for the toughened-epoxy systems that cure under vacuum bag pressure alone. A production autoclave sized for drone airframes is smaller than a wide-body aerospace autoclave but is still substantial — typical internal volume in the range of 30 to 80 cubic metres, operating at 180 degrees Celsius and 6 to 7 bar during the cure cycle, with a 4 to 8 hour cycle time.
The HVAC challenges in the autoclave hall are three. First, autoclave external surface heat rejection. Even with industrial lagging, the external surface of a production autoclave radiates 8 to 15 kW per cubic metre of internal volume during the heat-up phase. For a 50 cubic metre autoclave, peak thermal rejection is 400 to 750 kW. The autoclave hall HVAC has to remove this load to keep the workspace within acceptable worker comfort limits — typically below 28 degrees Celsius dry bulb at the operator working position. Second, control electronics conditioning. The autoclave control system, including the PLC, the thermocouple input multiplexers, the pressure transducers and the recipe storage, must operate within 18 to 24 degrees Celsius. This is delivered through a separately conditioned electronics enclosure or a conditioned cabinet adjacent to the autoclave. Third, loading bay vapour exhaust. When the autoclave door opens at the end of the cure cycle, residual solvent vapour, unreacted resin volatiles and the inert gas blanket (typically nitrogen) are released into the loading bay. A dedicated loading bay exhaust hood above the door, operating at high capture velocity during the door-opening phase, is the standard control. The exhaust ductwork is 304L stainless steel because of the temperature spike at door opening — the released air is at 60 to 100 degrees Celsius as the autoclave depressurises.
General autoclave hall ventilation runs at 6 to 10 air changes per hour, supplemented by spot cooling at operator working positions. Air handling units serving the autoclave hall are typically sized at 2 to 3 times the comfort cooling load to handle the peak heat rejection during autoclave heat-up cycles. SBKJ supplies SBAL-V galvanised supply duct and SBTF-1602 round tubeformer duct for the high-volume return paths in this scope.
Resin mixing and dispensing — the chemical fume hood
Epoxy, polyester, polyurethane and bismaleimide resin systems are mixed and dispensed at a dedicated resin station feeding the layup room and any wet-layup or infusion processes. The release profile depends on the resin chemistry. Polyester releases styrene at ambient mixing temperatures (Safe Work Australia WES is 50 ppm 8-hour TWA). Polyurethane systems release methylene diphenyl diisocyanate (MDI) particularly during heated dispensing (STEL 0.005 ppm — one of the most restrictive workplace exposure standards in any aerospace process). Epoxy systems release the amine hardener vapours and trace solvent (low ppm but sensitising). Bismaleimide systems release imide vapour during heated processing.
The HVAC control is source capture at the mixing station, sized per the ACGIH Industrial Ventilation Manual chapter on plastics manufacturing — 0.5 to 1.0 m/s capture velocity at the boundary of the release plume, with the actual velocity tuned to the resin system. Fume hood design uses a back-draught wall behind the mixing bench, with the operator working on the upstream side of the airflow path. The exhaust duct from the resin station is 304L stainless steel for the high-temperature portion and continues in 304L through to the fan discharge because mild steel and galvanised duct both corrode rapidly in continuous styrene and MDI service.
The fume hood face velocity is validated at commissioning with a NATA-traceable anemometer and is re-tested every six months. A drift in face velocity signals either fan degradation or hood door geometry change — both of which require investigation before further use. The duct is internally inspected annually for resin build-up at velocity transitions, particularly at the back-draught wall slot and the fan inlet cone.
SBKJ supplies SBAL-III stainless steel auto duct line for the rectangular fume hood ducting (14 m/min, 15.7 kW, accepting 304L coil through to 1500 mm width) and SBSF-1525 stitchwelder for the longitudinal seam to seal the duct against pinhole leakage. The SBTF-2020 round tubeformer is used for the cross-shop transport runs to the central fan, sized for the spiral round duct system that is more economical than rectangular over long runs.
Carbon fibre cutting and machining — respirable dust capture
Trim, drill, route, sand and grind operations on cured composite drone airframes produce one of the most challenging dust streams in industrial manufacturing. The dust is conductive (which threatens any energised electronics downstream of the migration path), abrasive (which wears the duct interior surface), fibrous (which catches in filter media and elbow transitions) and a confirmed respiratory and skin irritant. The Safe Work Australia respirable workplace exposure standard for carbon fibre dust is 5 mg per cubic metre, and the engineering controls must hold breathing-zone concentrations below that limit.
Three rules govern the HVAC specification for carbon fibre machining.
Rule one — source capture at every machining tool. Hood face velocity is sized per the ACGIH Industrial Ventilation Manual chapter on plastics manufacturing — typically 0.5 to 1.0 m/s for routing and trimming, 1.0 to 2.0 m/s for drilling, 2.0 to 2.5 m/s for grinding and abrasive operations. Capture at source is the only economically sustainable control — once dust escapes the machining tool it disperses across the building and recovery becomes orders of magnitude harder. The trim and grind hoods on a drone composite line are typically smaller than wind-blade or aerospace primary-structure hoods because the parts themselves are smaller, but the capture velocity requirement is identical.
Rule two — HEPA H13 or H14 final filtration mandatory. Carbon fibre dust at the respirable size fraction below 5 microns is the fraction that reaches deep lung tissue and is the binding occupational risk. HEPA H13 filtration at 99.95 per cent efficiency on 0.3 micron particles is the minimum acceptable specification before any return air is recirculated or before extracted air is discharged to atmosphere. H14 at 99.995 per cent is the common upgrade for newer plants that may want to extend filter service life and provide compliance margin.
Rule three — combustible dust evaluation. Bare dry carbon fibre dust by itself is not strongly combustible — it has a relatively high ignition energy and does not propagate flame readily in most conditions. But mixed-dust shops, where carbon fibre dust mixes with metal grinding residue from the same machining station, with paint over-spray from an adjacent paint booth or with coating residue, can produce explosive dust mixtures. The reference framework is NFPA 660 (the successor to NFPA 484 and NFPA 654) in the US, with AS 3957 as the Australian dust hazard analysis equivalent. Dust collectors serving mixed-dust shops are typically explosion-rated — vented to atmosphere through a deflagration vent, with isolation valves on the inlet ductwork.
The ductwork specification for carbon fibre dust extraction is antistatic-treated galvanised steel or 304L stainless steel with bonded electrical grounding for static dissipation. Carbon fibre dust accumulates electrostatic charge as it travels through the duct, and ungrounded duct sections can build up static potential that discharges through the dust cloud — the worst case scenario in a combustible-dust line. Duct velocity in the dust extraction system is in the 18 to 22 m/s range — high enough to transport the dust without settling, low enough to limit abrasive wear on the duct wall. Long-radius elbows are mandatory; short-radius elbows wear out in months of service on high dust loads. Cleanout doors at every change of direction and at every 6 metres of straight run are specified per NFPA 91.
SBKJ supplies the SBTF-1602 round tubeformer for the transport runs (galvanised round duct up to 1602 mm diameter, ideal for the high-velocity dust transport regime) and the SBAL-V auto duct line for the rectangular supply offset to the machining hall. The SBSF-1525 stitchwelder is used for the stainless steel portion of the duct serving abrasive operations where the dust load makes corrosion an additional concern.
3D printing room — VOC, UV resin and nylon powder
Additive manufacturing has moved from a prototyping technology to a production technology in the drone industry over the past decade. A modern drone facility typically runs three or four 3D printing technologies in parallel: fused deposition modelling (FDM) for prototype housings and jigs, stereolithography (SLA) for fine-feature parts and tooling masters, selective laser sintering (SLS) for nylon production parts, and metal printing (DMLS) for selected motor mounts and antenna fittings. Each technology has a different HVAC profile and the streams should never be combined.
FDM machines extrude thermoplastic filament (ABS, PLA, PETG, PA, PC) at temperatures between 200 and 300 degrees Celsius. The release profile includes thermoplastic VOCs (styrene from ABS, lactic acid from PLA, ethylene glycol from PETG) and ultrafine particles below 0.1 micron that are generated by thermal degradation of the filament. The HVAC control is dedicated extract over each printer with HEPA H13 or H14 filtration on the discharge. Galvanised duct is acceptable. Velocity 8 to 12 m/s.
SLA and DLP photopolymer printers use liquid UV-curable resin that releases uncured photopolymer aerosol during print and post-cure. The volatile is irritating and is corrosive to mild steel and galvanised steel over time. The HVAC duct on SLA exhaust is 304L stainless steel because the resin vapour degrades alternative materials within months. Capture velocity over the resin vat at 0.5 to 1.0 m/s. Activated carbon filtration on the discharge for VOC removal before stack discharge.
SLS nylon powder printers handle respirable polyamide powder that is a sensitising respiratory irritant. The release profile is dust during powder handling, refill and cake-removal phases. The HVAC control is dedicated extraction at the powder handling station with HEPA H13 filtration. Powder transport in the duct is at 18 to 22 m/s (same velocity regime as carbon fibre dust) with antistatic bonding because nylon powder accumulates electrostatic charge. The dust hazard analysis under AS 3957 typically classifies nylon powder as a combustible dust at fine particle sizes.
Metal DMLS printers handle reactive metal powders (titanium, aluminium, stainless steel, nickel alloy). The powder handling, recycling and post-process steps are the dominant HVAC controls. For drone-scale metal printing the powder volumes are small but the hazard profile is high — titanium powder is pyrophoric, aluminium powder is explosive at fine particle sizes, and combined-stream extraction is the failure mode that has destroyed multiple international metal-printing facilities. Each metal has a dedicated extraction system; the combustible-dust evaluation is performed by a specialist consultant.
Electronics assembly hall — ESD-controlled at IPC-A-610 Class 3
The electronics assembly hall is the second most HVAC-demanding zone in a drone facility, behind the composite layup room. The work is performed under IEC 61340-5-1 ESD Control with IPC-A-610 Class 3 workmanship — the standards for aerospace and military electronics. The HVAC contribution is humidity stability, temperature stability, low particulate and a quiet supply pattern that does not stir dust or charge operators.
Humidity is the binding control. ESD susceptibility in unprotected electronics rises sharply below 30 per cent relative humidity, and the threshold for typical drone electronics (MEMS gyroscopes, accelerometers, surface-mount semiconductors, lithium battery management ICs) is set conservatively at 30 per cent minimum. The working setpoint is 45 ±5 per cent RH, which gives both ESD margin and operator comfort. Temperature is 22 ±2 degrees Celsius. Particulate is at ISO 14644 Class 8 baseline for general assembly, with Class 7 for the avionics integration cell.
Air supply velocity at the bench is kept low — typically below 0.3 m/s at the working surface — because forced airflow over a moving fabric or polymer surface generates triboelectric charging on the operator's clothing. Ceiling-mounted fabric sock diffusers, large-area perforated panel diffusers or low-velocity displacement supply are the common choices. The conventional four-way blow ceiling diffuser is not appropriate.
Ductwork is galvanised lockformed sheet duct under SMACNA Class 6 or AS 4254 equivalent for the bulk supply and return. Every flange joint is bonded to the building grounding system because the duct itself sits inside the ESD control envelope and any ungrounded conductive section can hold static potential. The bond-resistance acceptance test at commissioning is part of the ESD audit.
SBKJ supplies SBAL-V auto duct line for the bulk supply and return ductwork to the electronics assembly halls (galvanised coil up to 1500 mm width at 16 m/min through-line speed). The SBAL-II auto duct line (smaller-scale at 18 m/min throughput and 5.5 kW installed power) is suitable for smaller drone-manufacturing electronics halls that do not justify the SBAL-V investment. For the avionics integration cell with its ISO Class 7 cleanliness overlay we recommend internally polished or epoxy-coated galvanised duct through the same SBAL-V line.
Avionics integration cell — autopilot and flight controller assembly
The avionics integration cell is a higher-grade subset of the electronics assembly hall. The work is assembly and validation of the autopilot, flight controller, inertial measurement unit, magnetometer and radio link — the systems that fly the aircraft and that constitute the most ESD-sensitive and most contamination-sensitive electronics on the platform.
The HVAC envelope is held to ISO 14644 Class 7 cleanliness (more stringent than the surrounding electronics hall), 45 ±5 per cent RH, 22 ±2 degrees Celsius and below 0.25 m/s supply velocity at the workbench. The cell is typically a softwall or hardwall cleanroom enclosure within the larger electronics hall, with positive pressure relative to the surrounding hall and a gowning vestibule at the entry.
The dedicated air handling unit serving the avionics cell has HEPA H13 filtration on the supply with ULPA filtration on the recirculation path. The supply ductwork inside the cell is 304L stainless steel internally polished or epoxy-coated galvanised steel, with low-leakage TDF flanges. The return ductwork is similarly clean — return is a primary contamination pathway and the standard practice of unducted return through a plenum is not appropriate.
The avionics integration cell is also typically the site of in-house calibration and acceptance test for the inertial measurement unit, magnetometer and pressure sensors. Calibration is performed inside a separately conditioned environmental chamber and the HVAC ductwork supplying that chamber is sized for the chamber's worst-case heat load (typically a few hundred watts of self-generated heat that must be removed during the test).
Battery assembly and test — NFPA 855 and AS/NZS 5139
Lithium-ion battery handling is one of the highest-stakes engineering disciplines in the drone industry. The energy density of modern lithium polymer and lithium-ion cells (200 to 280 Wh/kg) means that a single damaged cell can deliver a thermal runaway event with peak gas temperature above 600 degrees Celsius and a venting volume of several litres of flammable, corrosive electrolyte vapour. The HVAC engineering has to manage two distinct rooms: the battery assembly room (controlled, ESD-protected, normal occupied) and the battery test chamber (uninhabited during test, designed to contain a worst-case runaway).
Battery assembly room HVAC
The assembly of cells into drone-scale battery packs is performed in an ESD-controlled clean environment with humidity below the dew point of any cell handling activity. The setpoint is 22 ±2 degrees Celsius and 30 ±5 per cent RH (lower than the avionics hall because the lithium chemistry is moisture-sensitive). ESD control follows IEC 61340-5-1. Particulate cleanliness is ISO Class 8.
The assembly room is held at slight negative pressure relative to the surrounding workshop (typically 25 Pa below ambient). The negative-pressure logic is the opposite of the layup room — in the layup room we hold positive pressure to keep dust out, in the battery assembly room we hold negative pressure to contain any single-cell incident before it migrates outward. Dedicated extract at each assembly bench captures any single-cell thermal event before it propagates.
The duct system is galvanised lockformed sheet duct (SBAL-V supply) with bonded grounding throughout. Return ducting includes electrolyte vapour sensing — typically a continuous hydrogen fluoride sensor and a continuous carbon monoxide sensor at the AHU return — to trigger automatic isolation and dump if a runaway event begins.
Battery abuse test chamber HVAC
The abuse test chamber is the room where cell-level and pack-level abuse testing — overcharge, short-circuit, nail penetration, mechanical crush, thermal abuse, freezer-shock — is performed. The chamber is treated as if every test will release the worst-case venting event, and the HVAC engineering accordingly contains, dumps and signals.
The five HVAC controls on a battery test chamber are interlocked.
First, the chamber is held under continuous negative pressure relative to the corridor (typically 50 Pa below ambient). Any vented gas migrates outward through the dedicated dump rather than into adjacent workspace. The negative pressure is maintained by a continuous dedicated extract fan, independent of the building HVAC. The chamber is built with welded crevice-free ductwork on every internal penetration to maintain the pressure differential against the predicted vent volume.
Second, the dump duct discharges through a dedicated stack with no recirculation. The stack is sized for the worst-case vent volume of the largest battery on the test schedule, with a peak transient gas temperature exceeding 600 degrees Celsius and peak particulate loading at the order of grams per cubic metre. The dump duct material is welded 304L or 316L stainless steel at heavier gauge than commercial duct because the temperature transient and the chemical aggression of vented electrolyte (hydrogen fluoride, carbon monoxide, methane, ethylene, ethane) degrade lighter materials.
Third, multi-sensor detection triggers automatic isolation and dump activation. The sensor suite includes smoke detection at multiple points, carbon monoxide above 100 ppm threshold, hydrogen fluoride above 1 ppm threshold, voltage drop on the cell under test, temperature rise on the cell skin and pressure rise inside the chamber. Any single sensor trip triggers the dump cycle: the test chamber is sealed from the corridor, the dedicated extract fan ramps to maximum capacity, and the fire suppression system is armed. The dump cycle continues for a defined hold time after the last trip clears, before the chamber is re-opened for inspection.
Fourth, the chamber is electrically classified under AS/NZS 60079 Zone 2 because vented electrolyte vapour is flammable. All equipment inside the zone — including light fittings, motors and the test instrumentation — is rated to the relevant gas group (typically IIB or IIC) and temperature class (typically T3 or T4). The dump fan is also AS/NZS 60079 rated, because the worst-case scenario it handles is the vented gas itself.
Fifth, the chamber is separated from any storage room or workshop by a fire-rated separation, and the dump duct is routed away from any adjacent workspace and any building intake. The dump stack typically rises above the roof line of the building and discharges to atmosphere through a weatherproofed termination.
SBKJ supplies the SBSF-1525 stitchwelder for the welded stainless steel plenum on the test chamber ductwork and the SBTF-1602 round tubeformer for the round dump duct. The heavier-gauge sections of the dump stack — where heavy gauge welded stainless is required — are typically performed by a specialist welded-fabrication subcontractor with the appropriate pressure-vessel qualification, with SBKJ supplying the surrounding sheet-metal scope.
Motor and ESC assembly — clean ESD
Brushless DC motor assembly and electronic speed controller (ESC) assembly is a clean ESD work environment similar to general electronics. The motors are wound, magnetised, balanced and electrically tested before going to final integration. The ESCs are populated, programmed and burn-in tested before going to integration.
The HVAC envelope is the same as the general electronics hall — 22 ±2 degrees Celsius, 45 ±5 per cent RH, ISO Class 8, ESD-controlled. The added consideration is that motor balancing test rigs may release fine particulate from rotor-stator interaction during the spin-test phase, and that magnetising and demagnetising stations release weak magnetic fields that may affect adjacent equipment. Local extract at the balancing rig is sized for the particulate release. The magnetising station is sited away from precision instrumentation.
Burn-in test of ESCs at full load generates substantial thermal output (a single 60 amp ESC dissipates 10 to 20 watts at burn-in load, and a typical burn-in rack runs 50 to 100 ESCs in parallel). The burn-in rack is a heat-generating fixture in the room and the HVAC has to remove the rack's thermal output without disturbing the ESD or particulate envelope. Local extract at the rack with the extract air filtered before recirculation is the standard approach.
Ductwork is galvanised lockformed sheet, SBAL-V auto duct line supply. No specialist material required.
Final integration and functional test
The final integration floor is where subsystems come together onto the airframe — wing meets fuselage, propulsion meets airframe, battery meets electronics, payload meets platform. The floor is also where functional ground tests and pre-flight check-out are performed. The HVAC profile is the simplest in the facility — a clean working environment with minimal process exhaust.
General dilution ventilation at 4 to 6 air changes per hour is sufficient for the bulk of the integration floor. Temperature and humidity setpoints are operator comfort (22 ±3 degrees Celsius, 40 to 60 per cent RH). Particulate is ISO Class 8 baseline because the avionics and the electronics are still exposed during integration. The duct system is conventional galvanised lockformed sheet under SMACNA Class 6 or AS 4254 equivalent — SBAL-V auto duct line supply.
The test phase may include ground-run of motors with propellers fitted. Propeller ground-run is a localised noise and particulate source — small UAS propellers running at 4,000 to 10,000 RPM are loud and may release small composite particles if any are loose on the prop surface. Localised extract at any propeller test rig manages both the acoustic and the particulate release. Some facilities use a dedicated propeller test cell with acoustic absorber lining and separately exhausted air to keep the noise contained.
The final integration floor is also where the platform first powers up with full battery installed. The HVAC system has to remain in a known state during first power-up because any abnormal battery behaviour at first power-up is a candidate for thermal runaway — and the same multi-sensor detection package that protects the battery test chamber applies, at lower density, to the final integration area. Continuous CO and HF monitoring at the integration bay is the standard control.
RF anechoic chamber HVAC
Drone, UAV and counter-UAS programmes use RF anechoic chambers for antenna pattern testing, electromagnetic compatibility (EMC) validation, radio link characterisation and counter-UAS RF disruption testing. The room is RF-shielded (typically a soldered or seamed steel enclosure) and acoustically lined with absorbing foam pyramids. The HVAC challenge is to condition the chamber without compromising the RF or acoustic measurement.
Every HVAC duct penetration through the RF-shielded envelope is a potential RF antenna. The engineering response is a waveguide-below-cutoff (WBC) penetration — a length of conductive duct (steel or copper) sized so that the cutoff frequency of the duct cross-section exceeds the upper test frequency of the chamber. For typical drone test frequencies up to 6 to 18 GHz, this requires WBC tubes with internal dimensions much smaller than full-flow duct, so the duct cross-section is divided into a honeycomb array of small WBC cells. The honeycomb assembly passes air with acceptable pressure drop while maintaining shielding effectiveness typically in the 60 to 100 dB range.
Inside the chamber the supply diffusion is low-velocity textile or perforated panel because forced-air noise corrupts the acoustic measurement during pattern testing. The duct surfaces inside the chamber are sometimes lined with acoustic absorber material to suppress reverberation. Diffuser face velocity is below 0.5 m/s. Air movement is sufficient to remove the equipment heat load (typically several kilowatts from the device-under-test and the supporting instrumentation) but not so high that it disturbs the measurement.
The chamber temperature setpoint is normally 22 ±2 degrees Celsius for operator comfort and equipment stability. Humidity is set at 40 to 50 per cent RH. The dedicated AHU serving the chamber has a separate chilled water loop and a dedicated controller, because the chamber is operated in cycles (test on / test off) and the AHU has to ramp without overshooting the band.
SBKJ supplies the SBSF-1525 stitchwelder for the stainless steel plenum on the chamber ductwork (welded longitudinal seams reduce leakage and reduce RF-leakage potential). The WBC honeycomb assemblies are specialty products supplied by a small number of approved manufacturers and are integrated by the chamber-shielding contractor.
Counter-UAS RF testing and TEMPEST-shielded rooms
Counter-UAS testing — the validation of detection, identification and disruption performance — is performed inside Faraday-shielded environments to prevent RF leakage that could interfere with adjacent civil RF spectrum or licensed users. DroneShield, Saab Australia, Penten and the wider counter-UAS supply chain each operate one or more shielded test rooms. The shielding requirements range from standard EMC-grade RF shielding (60 to 80 dB attenuation) to full TEMPEST emanation control (100+ dB attenuation, controlled access, classified zone).
The HVAC duct engineering inside a TEMPEST-shielded room follows the same logic as the anechoic chamber but with additional layers. First, classified-zone HVAC ducts are routed only inside the shielded envelope. Unclassified-zone HVAC ducts never enter the classified envelope. AHU return paths are physically separate between classified and unclassified zones — there is no shared return-air plenum, no shared duct bank and no shared atmospheric bypass. This zoning is set at architectural concept stage and is non-negotiable in retrofit.
Second, every duct penetration through the shielded boundary uses a waveguide-below-cutoff assembly sized for the TEMPEST threat spectrum. The honeycomb cell dimensions are typically smaller than commercial EMC honeycomb because the threat spectrum extends higher in frequency. Defence Signals Directorate guidance and US NSA TEMPEST Level 1, 2 or 3 designate the rigour required.
Third, inside the shielded envelope the duct is continuous-welded steel with bonded conductive gaskets at every flange. The flange gasket is typically a beryllium-copper finger-stock or a conductive elastomer rated for the relevant attenuation band. SBKJ supplies the lighter-gauge welded sheet portion (using the SBSF-1525 stitchwelder for the longitudinal seams) and refers customers to specialist welded-fabrication subcontractors for the heavy-gauge welded duct that is required on the highest-classification facilities.
Fourth, the country-of-manufacture of every ducted component is auditable. Fans, dampers, sensors and controllers inside the classified envelope are typically restricted to Five Eyes-aligned country of manufacture on the higher classification levels. SBKJ Group operates as a Box Hill North Victoria Australian-based supplier inside the Australian Industry Capability framework, which supports the audit chain.
Paint booth — military camo finishing
Military uncrewed systems are finished in low-visibility camouflage paint or radar-absorbing coating before delivery. Civil uncrewed systems are finished in the customer livery. Either way the paint application is a spray-application process governed by NFPA 33 in the US and by AS/NZS 60079 plus AS 1668.2 plus AS 1940 in Australia.
The booth is a cross-draught or downdraught enclosure with capture velocity 0.5 to 1.0 m/s across the open face. The face velocity is the key compliance number — it has to be maintained even with the booth fully loaded and the filter back-pressure at end-of-life. AS/NZS 60079 Zone 1 classification applies inside the booth itself during application (extends to Zone 2 for a defined volume outside the booth). Electrical equipment inside the zone is rated to the corresponding gas group and temperature class.
The extract duct from the booth is 304L stainless steel because solvent vapour and over-spray particulate are corrosive. The exhaust train includes a pre-filter (capturing the bulk of the over-spray particulate), a final exhaust filter and a stack discharge per the relevant state environment authority — in Victoria the EPA Victoria, in New South Wales the EPA NSW, in Queensland the Department of Environment and Science.
The supply makeup-air train is typically heated in winter and cooled in summer to maintain the booth at 18 to 24 degrees Celsius. The supply duct is galvanised lockformed sheet on the upstream side of any filter, with the painted-air zone in stainless steel. The booth is heat-cure capable on military programmes — radar-absorbing coatings frequently require a low-temperature bake to consolidate the binder.
SBKJ supplies SBAL-V galvanised supply duct and SBAL-III stainless steel duct for the booth exhaust. The SBSF-1525 stitchwelder seals the longitudinal seams against pinhole leakage in continuous solvent service.
Calibration laboratory — ISO 17025 and NATA
Drone and UAV manufacturers seeking to maintain their own calibration capability for inertial measurement units, magnetometers, pressure sensors and motor balancing run an in-house ISO 17025-accredited calibration laboratory. NATA accreditation provides the third-party validation of competence in Australia. The HVAC contribution to the laboratory is environmental stability, validated through NATA-accepted measurement.
The setpoint is 20 ±0.5 degrees Celsius and 45 ±5 per cent RH. The short-term temperature stability is the binding control — the standard calibration measurement is sensitive to temperature drift during the measurement window, and a temperature transient during the cal cycle invalidates the measurement. The HVAC is dedicated AHU with redundant chilled water (dual chiller or chilled-water buffer tank), low-velocity supply, ceiling-mounted fabric or perforated diffusion, and continuous environmental monitoring reporting to the laboratory information management system (LIMS).
The duct system is galvanised lockformed sheet under SMACNA Class 6 or AS 4254 equivalent — the HVAC stability is delivered by the AHU and the controls, not by the duct itself. SBAL-V auto duct line supply is the standard fabrication route.
Spark-resistant duct for Mg, Al, Ti machining
Drone and UAV airframes use magnesium, aluminium and titanium components in motor mounts, transmission housings, structural fittings and propeller hubs. Machining these metals — particularly grinding, sanding and high-speed cutting — generates combustible dust covered by NFPA 660 (which incorporates the previous NFPA 484 for combustible metals) and AS 3957 for dust hazard analysis. Each metal carries a distinct hazard profile.
Magnesium dust ignites at very low energy (minimum ignition energy below 10 millijoules for fine particle sizes). The dust is also water-reactive in fine form — water spray on a magnesium dust fire intensifies the reaction. Magnesium dust extraction is handled with wet-precipitator collectors using non-aqueous fluid (mineral oil or a fire-resistant proprietary fluid).
Aluminium dust in fine particle size below 75 microns is explosive at concentrations above approximately 50 grams per cubic metre. The minimum ignition energy is in the order of 50 millijoules — higher than magnesium but still within the range achievable from static discharge in an ungrounded duct.
Titanium dust is pyrophoric in fine form — it ignites spontaneously in air at room temperature when the particle size is below approximately 50 microns. Titanium dust handling is the most demanding of the three.
The HVAC response is dedicated extraction for each metal, never combining streams. Combined-stream extraction of mixed metals is the failure mode that has destroyed multiple international facilities. The duct construction is spark-resistant — non-ferrous internal liner or polished stainless steel without rusted internal surface. The collectors are wet-precipitator dust collectors rather than dry filter for magnesium and titanium service. Deflagration venting on the collector vents any internal ignition to atmosphere. Isolation valves on inlet ducts prevent flame propagation back into the workshop. Full bonding for static dissipation prevents internal ignition from electrostatic discharge.
SBKJ supplies SBSF-1525 stainless steel stitchwelded duct for these services. The collector package itself — the wet precipitator, the deflagration vent assembly, the isolation valves and the explosion-rated fan — is supplied by a specialist combustible-dust handler with appropriate certification. We co-ordinate with the chosen specialist subcontractor at design and commissioning stage.
Materials specification by zone
The single most common rework item we see at drone facility HVAC commissioning is a duct material specification that does not match the duty. The six zone categories below cover the typical specification matrix.
General supply and return air — galvanised G275 (G90 equivalent) to AS/NZS 4254 or SMACNA. Standard galvanised duct construction for general HVAC supply and return outside the high-duty zones. Pressure class typically 500 Pa positive, 250 Pa negative. Sealing class C per AS/NZS 4254. SBAL-V or SBAL-III auto duct line.
Composite layup and cleanroom supply — 304L stainless internally polished, or epoxy-coated galvanised steel. Low-leakage TDF flange construction. Sealing Class A. The internal surface finish is the key compliance number. SBAL-III stainless line plus SBSF-1525 stitchwelder, or SBAL-V galvanised line plus internal epoxy coating.
Resin fume and chemical extract — 304L stainless welded. Continuous styrene, MDI or amine service degrades galvanised and butyl gasket in months. The duct is SBAL-III line with longitudinal seam stitchwelded at SBSF-1525 for pinhole-free sealing.
Carbon fibre dust extraction — antistatic-treated galvanised or 304L stainless, with bonded grounding. Velocity 18 to 22 m/s. Long-radius elbows. Cleanout doors at every change of direction. SBTF-1602 round tubeformer or SBAL-V auto duct line.
Battery test dump duct — welded heavy-gauge 304L or 316L stainless. Crevice-free welded construction. Heavier gauge than commercial. SBSF-1525 stitchwelder for the lighter-gauge sections, specialist welded-fabrication for the heavy-gauge stack.
Mg, Al, Ti combustible-dust extraction — stainless steel, spark-resistant, bonded. Each metal dedicated, never combined. Wet precipitator on the collector. Deflagration venting. SBSF-1525 stitchwelded 304L or 316L.
SBKJ machinery for drone facility HVAC fabrication
SBKJ Group supplies the fabrication machinery that produces the duct described in this guide. The machine range is sized for the typical Australian drone manufacturing duct contractor scope — 4,000 to 12,000 square metres of fabricated duct per year on a single-shift workshop, scaling to multi-shift on the larger AUKUS-aligned programmes.
SBAL-V auto duct line — the flagship
The SBAL-V is the flagship auto duct line in the SBKJ catalogue. The line runs galvanised coil up to 1500 mm width and 0.5 to 1.5 mm thickness at a through-line speed of 16 metres per minute, with 87 kW total installed power. The output is rectangular duct with TDF flanges, integrated longitudinal seam and notched/cut to length. Typical workshop output is 200 to 300 square metres of fabricated duct per shift, sized for the bulk supply and return scope on a drone facility — final integration floor, electronics assembly hall, autoclave hall comfort cooling, paint booth makeup-air and general dilution ventilation.
SBAL-III auto duct line — the mid-range
The SBAL-III runs at 14 metres per minute through-line speed with 15.7 kW installed power, the standard mid-range workhorse for drone-manufacturing contractors. The line accepts galvanised or 304L stainless coil to 1500 mm width and 0.5 to 1.5 mm thickness. The lower installed power and slower through-line speed of the SBAL-III suit smaller contractor workshops that do not justify the SBAL-V investment.
SBAL-II auto duct line — entry level
The SBAL-II runs at 18 metres per minute through-line speed with 5.5 kW installed power, a high-speed entry-level line for smaller-scale rectangular duct work. The SBAL-II is the right size for prototype drone facilities and for small-batch contractor work.
SBTF-1500C, SBTF-1602 and SBTF-2020 spiral tubeformers
The SBTF series produces round spiral duct. The SBTF-1500C produces round spiral duct up to 1500 mm diameter. The SBTF-1602 extends the diameter range to 1602 mm. The SBTF-2020 produces round spiral duct up to 2020 mm diameter — the largest round duct typically used in industrial dust extraction and high-volume supply applications. Round spiral duct is more economical than rectangular duct over long runs and is the preferred construction for the carbon fibre dust transport, the autoclave hall return and the battery test dump duct.
SBEM-1250 elbow former
The SBEM-1250 produces long-radius elbows up to 1250 mm in nominal dimension. Long-radius elbows are mandatory on the carbon fibre dust extraction system and are the preferred construction on every change of direction in the high-velocity dust transport ductwork.
SBSF-1525 stitchwelder
The SBSF-1525 stitchwelder seals longitudinal seams on stainless steel duct with installed power of 2.5 kW. The output is a longitudinal seam that approaches the leakage performance of a continuous-welded seam, at a fraction of the labour cost. The SBSF-1525 is the workhorse for the composite layup supply, the resin fume return, the battery test dump duct and the spark-resistant duct serving Mg, Al and Ti machining.
SBFB-1500 flange former
The SBFB-1500 produces TDF flanges with installed power of 7.5 kW running at 1.20 metres per minute. TDF flanges are the standard rectangular duct flange construction on every Australian drone facility HVAC scope. The flange-formed duct is then assembled with corner pieces and gasket for a sealed joint at the building site.
SBHF, SBPC1500, SBLR-600 / SBLR-600A
The SBHF hydraulic notch-and-fold machine, the SBPC1500 plasma-cutting CNC and the SBLR-600 and SBLR-600A laser cutters (7.6 metres per minute throughput on the laser scope) round out the SBKJ machine range for drone-facility duct fabrication. The plasma and laser scope is increasingly used for high-mix, low-volume cutting work on stainless steel and exotic alloy duct, which is characteristic of the bespoke ductwork required on drone test cells and specialised fabrication work.
The regulatory and security overlay — CASR, ASA-5000, ITAR, DSGL
Drone manufacturing HVAC operates inside a regulatory envelope that is denser than most commercial manufacturing. The HVAC contractor and the supplying engineer need a working awareness of four regulatory pathways.
Civil drone operation — CASR Part 101
Civil Aviation Safety Regulation Part 101 covers the use of remotely piloted aircraft (RPA) and rockets in Australian airspace. The regulation is administered by the Civil Aviation Safety Authority. Part 101 sets the rules for RPA operator certification, the categories of operation (excluded, sub-2 kg, standard RPA, beyond visual line-of-sight) and the airworthiness expectations on civil RPA. The HVAC contractor is not directly subject to CASR Part 101 but the facility is — facility operations, test flight operations and operator training fall under the Part 101 framework where civil aircraft are involved.
Military aviation — ASA-5000
The Defence Aviation Safety Regulations ASA-5000 series, issued by the Defence Aviation Authority within the Department of Defence, govern military aircraft including military uncrewed systems. Manufacturers of MQ-28 Ghost Bat, Strix, Drone40, Ghost Shark and other military uncrewed platforms operate inside the ASA-5000 framework. The HVAC contractor working on a military-aircraft manufacturing facility may need Defence Industry Security Programme membership and may need awareness of the controlled-access portions of the facility.
Defence trade controls and the DSGL
The Defence Trade Controls Act 2012 regulates the export, brokering and publication of military and dual-use technology under the Defence and Strategic Goods List (DSGL). Counter-UAS RF disruption equipment, military uncrewed systems, certain composite materials, certain electronics and certain test equipment are typically captured by the DSGL. The HVAC contractor working inside a DSGL-covered facility needs awareness of which areas of the facility are export-controlled, what records are retained and what reporting is required if controlled materials cross the facility boundary.
Defence Export Controls within the Department of Defence administers the Act. On bilateral programmes the US International Traffic in Arms Regulations (ITAR) may also apply, particularly on programmes with US prime contractors or US-origin technology. The European Union Dual-Use Regulation 2021/821 applies on exports to and from the EU.
International export pathways
US FAA Part 107 covers civil drone operation in US airspace and is relevant for any Australian-built civil drone exported to the United States. EASA UAS Regulation 2019/947 (operations) and 2019/945 (technical requirements) cover the European pathway. Operator certification and airworthiness pathways for export markets are distinct from the Australian pathways and the manufacturer typically engages a regulatory affairs specialist for each market.
Defence Industry Security Programme
The Defence Industry Security Programme (DISP) is the security accreditation scheme for Australian defence industry. DISP Member Entry Level is the minimum threshold to work on most defence sites. DISP Level 1 is required for handling Official information. DISP Level 2 is required for Protected information, including most classified ICT facilities. DISP Level 3 covers Secret-level work and is needed for specialist hardened command and intelligence facilities. Above DISP Level 3, work touching Top Secret information requires NV2 or PV personnel clearance through the Australian Government Security Vetting Agency (AGSVA). HVAC contractors working on military uncrewed systems facilities typically operate at DISP Level 1 or 2.
How SBKJ supports Australian drone manufacturing HVAC
SBKJ Group operates from Box Hill North Victoria as an Australian-based supplier of HVAC duct fabrication machinery and engineering services. We support drone, UAV and counter-UAS manufacturers across four engagement modes.
The first mode is auto duct line and spiral tubeformer machinery supply. We sell, install, commission and maintain the duct fabrication machinery in the contractor's workshop. This is the principal commercial relationship and is well-suited to mid-size and large drone-manufacturing duct contractors building 4,000 to 12,000 square metres of fabricated duct per year.
The second mode is engineering consultation on duct specification and material selection. SBKJ engineers have 30+ years of cumulative experience across composite, electronics, hazardous-area and classified facility work. Where a drone facility specification requires resolution between AS/NZS 4254, SMACNA, EN 1505 and DW/144 standards, our engineers provide the cross-walk.
The third mode is sub-supply through prime contractors on AUKUS-aligned and Defence-aligned uncrewed-systems projects. SBKJ machinery and engineering services are routinely supplied through prime contractors who hold the head DISP accreditation and the contractual relationship with the customer. SBKJ Group operates inside the Australian Industry Capability framework that supports AIC content reporting on these programmes.
The fourth mode is co-ordination with specialist subcontractors on heavy-gauge welded, EMP-shielded, TEMPEST-shielded and combustible-dust collector scope. For portions of a drone facility that fall outside SBKJ's standard machinery scope, we co-ordinate with the contractor's chosen specialist subcontractor to ensure that the lighter-gauge sheet-metal scope and the heavier-gauge welded scope integrate cleanly at the project boundary.
FAQ
What HVAC standards apply to an Australian drone or UAV manufacturing facility?
Civilian baseline AS 1668.2, AS 4254 and AS 1530.4. Process overlays IPC-A-610 Class 3 (aerospace and military electronics), IEC 61340-5-1 (ESD), ISO 14644 (cleanroom) Class 7 to 8, NFPA 855 and AS/NZS 5139 (lithium-ion battery), NFPA 660 (formerly NFPA 484 — combustible metals), AS 1940 (flammable liquids), AS/NZS 60079 (hazardous area), AS 3957 (dust hazard), ISO 17025 (calibration). Regulatory overlays CASR Part 101 (civil), ASA-5000 (military), Defence Trade Controls Act 2012 and DSGL (export).
Why is the composite layup room the most demanding HVAC zone?
ISO Class 8 cleanliness, 22 ±2 degrees Celsius for prepreg out-life, 50 ±5 per cent RH for resin tack, below 0.25 m/s surface velocity to avoid stirring loose carbon fibre. Carbon fibre is conductive — fibre migration into the electronics hall is a latent short-circuit risk. HEPA H13 supply through 304L stainless or epoxy-coated galvanised duct. Positive pressure relative to corridor.
How is the lithium-ion battery test chamber HVAC designed?
Negative pressure to corridor. Dedicated dump stack with no recirculation. Multi-sensor detection (smoke, CO, HF, voltage drop, temperature rise) for automatic isolation. Heavier-gauge welded stainless steel dump duct because peak gas temperature exceeds 600 degrees Celsius. AS/NZS 60079 Zone 2 electrical classification because vented electrolyte vapour is flammable. NFPA 855 and AS/NZS 5139 references.
What ESD control does avionics assembly need?
IEC 61340-5-1 ESD Protected Area with IPC-A-610 Class 3 workmanship. 45 ±5 per cent RH (ESD susceptibility rises sharply below 30 per cent RH), 22 ±2 degrees Celsius, below 0.3 m/s supply velocity at the bench. Galvanised lockformed sheet duct with bonded grounding at every flange. Avionics integration cell at ISO Class 7 inside a softwall or hardwall cleanroom enclosure with dedicated AHU and HEPA H13 supply.
How is the carbon fibre dust extraction designed?
Source capture at every machining tool — 1.0 to 2.0 m/s capture velocity per the ACGIH Industrial Ventilation Manual. Transport at 18 to 22 m/s in antistatic-treated galvanised or 304L stainless duct with bonded grounding. HEPA H13 or H14 final filtration. Long-radius elbows mandatory. Cleanout doors at every change of direction per NFPA 91. NFPA 660 dust hazard analysis for any mixed-dust shop.
How does TEMPEST emanation control affect drone facility HVAC?
Classified-zone HVAC ducts routed only inside the shielded envelope. Unclassified-zone HVAC ducts never enter the classified envelope. Separate AHU return paths. Waveguide-below-cutoff penetrations at every duct crossing of the boundary, sized for the TEMPEST threat spectrum. Continuous-welded steel duct inside the envelope with bonded conductive gaskets at every flange. Country-of-manufacture audit on every ducted component.
What is the spark-resistant duct for Mg, Al, Ti machining?
Dedicated extraction for each metal — never combined. Spark-resistant duct (non-ferrous internal liner or polished stainless without rusted internal surface). Wet-precipitator collectors for magnesium and titanium service. Deflagration venting on the collector. Isolation valves on inlet ducts. Full static bonding throughout. NFPA 660 (formerly NFPA 484) and AS 3957 framework.
Which Australian drone operators drive HVAC duct demand?
DroneShield (Sydney — counter-UAS), Boeing Defence Australia (MQ-28 Ghost Bat Wellcamp QLD), Innovaero (Bayswater WA — Strix and AIM-9X Marauder), AMSL Aero (Bankstown NSW — Vertiia eVTOL), Carbonix (Sydney — VTOL), Insitu Pacific (Boeing — ScanEagle), Quickstep ASX:QHL (Bankstown NSW and Geelong VIC — F-35 composite), Marand Precision Engineering (Moorabbin VIC), Anduril Australia (Adelaide — Ghost Shark XL-UUV), DefendTex (Melbourne — Drone40), Saab Australia (Adelaide — Giraffe radar), Penten (Canberra), DSTG Edinburgh SA and Fishermans Bend VIC, Lovitt Technologies Australia, Ferra Engineering Brisbane, Levett Engineering Adelaide, HEICO Australia, Reaction Engines Australia, Skyborne Technologies, Stealth Technologies, AOS Group Defence and the Robotics Australia Group industry body.
What does the export-control overlay mean for HVAC contractors?
The Defence Trade Controls Act 2012 and the Defence and Strategic Goods List (DSGL) regulate the export of military and dual-use technology. Counter-UAS equipment, military uncrewed systems, certain composite materials, certain electronics and certain test equipment are typically captured. HVAC contractors need awareness of which areas of the facility are export-controlled, what records are retained and what reporting is required if controlled materials cross the facility boundary. On bilateral programmes US ITAR may also apply. DISP Member Entry Level minimum for most defence sites, Level 1 to 3 for higher classifications.
