Switchgear, Transformer, Electrical Equipment, Motor & Generator Manufacturing HVAC Duct Guide

1. Why electrical-equipment manufacturing HVAC is its own engineering discipline

Switchgear, transformer, motor and generator manufacturing is one of the most chemically diverse heavy-industrial sectors in the Australian economy, and its HVAC demands reflect that diversity. Within a single plant — the Wilson Transformer Company works at Glen Waverley and Wodonga in Victoria, the NHP switchboard and switchgear facility at Richmond, a NOJA Power recloser line at Murarrie in Queensland, or an Ampcontrol mining-electrical shop in Newcastle — you can find polyester and epoxy impregnating varnish flashing off styrene in the winding shop, hot mineral or ester insulating oil throwing a fine mist in the tanking hall, sulphur hexafluoride and its corrosive arc by-products in the gas-insulated switchgear bay, epoxy and acid-anhydride hardener curing in the cast-resin shop, powder-coat overspray and a 200 degrees C cure oven on the enclosure line, and a high-voltage test bay generating ozone while rejecting hundreds of kilowatts of heat-run load. Each process carries its own fume chemistry, ignition risk, hazardous-area zoning requirement, corrosion profile and material specification. HVAC ductwork inside an electrical-equipment plant is not a commodity item. It is a process-engineering problem that touches AS/NZS 60079 hazardous-area electrical compliance, AS 1940 flammable-liquid handling, AS 1375 industrial-oven safety, AS 3957 combustible-dust deflagration safety, AS/NZS 1554 weld-fume control and the AS 60076 and AS 62271 product standards that govern how the finished transformers and switchgear are tested.

This guide writes against the full breadth of the Australian electrical-equipment manufacturing sector as it exists in 2026. Transformers are anchored by Wilson Transformer Company, Australia’s largest transformer maker, with power-transformer manufacturing at Glen Waverley and Wodonga in Victoria covering distribution, power and large grid transformers in mineral and ester insulating oil. Switchgear and switchboards are dominated by NHP Electrical Engineering Products at Richmond VIC, with a national network of switchboard builders including B&R Enclosures (enclosure manufacturing), Australian Switchgear, Power & Electrical Switchgear, Cabac, Terasaki and Gibson Engineering. NOJA Power at Murarrie QLD is the Australian-grown global leader in pole-mounted automatic circuit reclosers, exporting recloser switchgear worldwide. Schneider Electric Australia, ABB Australia and Siemens Australia run local manufacturing, assembly and test operations across switchgear, transformers, drives and protection. Hyundai (Australian operations only) supports switchgear and transformer supply into the local market.

Motors and generators are covered by Regal Beloit and the CMG motor brand, TECO Australia and a network of motor rewind and generator-assembly shops, all of which run winding, varnish/impregnation, commutator and test operations. The renewable-energy and power-electronics tier — Fimer/ABB inverters, Tritium EV chargers (Brisbane), and the broader battery, UPS and inverter-assembly sector — brings solder fume, electronics assembly and high-power test loads. Ampcontrol in Newcastle NSW is the country’s leading manufacturer of mining and industrial electrical equipment, building flameproof and explosion-protected switchgear, transformers and power systems for the resources sector. Across all of these, the duct that carries varnish solvent, oil mist, SF6 by-products, brazing and plating fume, powder-coat overspray, epoxy/anhydride vapour and weld fume to atmosphere — and the supply air that tempers the winding shops, cleanrooms and megawatt-scale test bays — is purpose-engineered, not generic commercial duct.

Across this entire sector, electrical-equipment manufacturing ductwork must survive several simultaneous demands. Solvent and sensitiser fume resistance (styrene and xylene from VPI varnish, isocyanate and anhydride from resin systems, IPA from cleaning). Corrosion resistance (hydrogen fluoride and SOF2 from SF6 arc by-products, plating-acid mist, fluoride brazing flux, transformer-oil acidity). High-temperature service (120–160 degrees C VPI cure, 180–200 degrees C powder-coat cure, 120–150 degrees C cast-resin cure, and the heat-run test load). Combustible-dust deflagration resistance (powder-coat overspray under AS 3957 and AS/NZS 60079). And large thermal loads (the high-voltage and heat-run test bays rejecting copper and iron loss as heat). Each is manageable in isolation. Together they explain why a generic commercial fabricator treating a transformer or switchgear plant as just another industrial job loses money on the first project and walks away from the second.

This guide walks every major process zone in an electrical-equipment plant and explains what changes about the ductwork. We start with the regulatory backbone, then map the plant section by section — winding/varnish, core/tanking, oil processing, SF6 GIS, busbar/brazing/plating, enclosure fabrication and powder coat, cast resin, motor/generator, the HV and heat-run test bays, battery/UPS/inverter and solder/electronics — then close with hazardous-area classification, the dilution calculation, the SBKJ machine configuration, commissioning, the standards table, the energy and electrification context, and the industry-body landscape that frame this market for an Australian fabricator working from Box Hill North VIC.

2. The Australian regulatory stack — AS 1668.1, AS 1668.2, AS 4254, AS 1530.4, AS 1940, AS 1375, AS/NZS 60079, AS 3957, AS/NZS 1554, AS 60076, AS 62271, NCC Section J, ASHRAE 62.1

Electrical-equipment manufacturing HVAC in Australia sits at the intersection of more than two dozen overlapping standards and codes. Ignoring any one of them is a notice-of-non-compliance from SafeWork Australia, the state EPA, or the relevant electrical-safety regulator waiting to happen. The standards stack splits into building-code and mechanical-ventilation compliance, occupational-health exposure compliance, hazardous-area electrical compliance, flammable-liquid and oven safety, combustible-dust safety, weld-fume control, and the product-standard context that determines how the finished equipment is tested.

2.1 AS 1668.1 and AS 1668.2 — the mechanical-ventilation backbone

AS 1668.1 covers the fire aspects of air-handling systems — smoke management, fire dampers, fire-mode shutdown — while AS 1668.2 is the umbrella mechanical-ventilation standard for Australia, covering general ventilation, contaminant dilution and the use of workplace exposure standards (WES) to size dilution flow. Electrical-equipment plants fall under NCC Class 8 industrial occupancy. AS 1668.2 Appendix material gives the dilution-ventilation method that an engineer uses to size general ventilation against the controlling WES for solvent vapour (styrene, xylene, toluene), oil mist, ozone and the SF6 by-product set. In practice the plant seldom relies on dilution alone — localised exhaust ventilation (LEV) at each varnish dip, oven hood, brazing bench, plating tank and powder-coat booth drives total exhaust well above the building-volume figure. Where AS 1668.2 matters most is the make-up air requirement: every cubic metre extracted from a VPI cure oven, a powder-coat booth, an SF6 bay or a heat-run cell must be replaced by tempered, filtered, controlled-velocity supply air, keeping the production zones at neutral or slightly positive pressure relative to office and clean-assembly zones, and preventing solvent vapour or SF6 back-migration into occupied spaces.

2.2 AS 4254.1 and AS 4254.2 — sheet-metal and flexible duct construction

AS 4254.1 (sheet metal) and AS 4254.2 (flexible) govern duct construction across normal pressure ranges — low pressure (up to 500 Pa), medium pressure (up to 1000 Pa) and high pressure (up to 2500 Pa). Most electrical-equipment plant supply air, general extract and solvent/fume LEV sit inside AS 4254 ranges. The VPI cure oven, powder-coat cure oven and heat-run exhaust in their high-temperature stainless sections run beyond the temperature scope that ordinary AS 4254 galvanised construction assumes; AS 4254 picks up again on the cool side downstream of the cooling and dilution zone. AS 4254 sets the gauge-versus-pressure-versus-dimension construction tables, the joint and stiffener requirements, and the leakage classes that the commissioning pressure test verifies.

2.3 AS 1530.4 — fire-resistance of building elements

AS 1530.4 covers fire-resistance testing of building elements including fire-rated ductwork penetrations through fire compartments. In an electrical-equipment plant this matters at every wall and floor penetration between the varnish, oil, solvent and resin production zones (which carry a real fire load) and adjacent office, laboratory, test, server or evacuation zones. The duct penetration must be rated at 250 degrees C / 2 hour fire integrity, with fire dampers complying with AS 1682 and the surrounding wall/floor assembly meeting the fire-resistance level (FRL) called by the building’s National Construction Code (NCC) approval. The VPI cure oven and the solvent store, in particular, sit behind fire-rated separation, and the exhaust duct leaving them crosses that boundary as a rated penetration.

2.4 AS 1940 — storage and handling of flammable and combustible liquids

AS 1940 governs the storage and handling of flammable and combustible liquids in Australian workplaces, and electrical-equipment plants are full of them. Impregnating varnish (polyester and epoxy, carrying styrene, xylene and white-spirit solvent) is a flammable liquid stored under AS 1940 with bunded containment and dedicated extraction. Transformer insulating oil — mineral oil and the newer natural and synthetic ester fluids — is a combustible liquid; the oil-filling and degassing hall is an AS 1940 area with hot-oil handling. Isopropanol (IPA) and other cleaning solvents are flammable liquids. Each storage and handling point requires bunded containment, a dedicated LEV branch, a segregated storage cabinet or store, and AS/NZS 60079 hazardous-area zoning around the immediate work area. AS 1940 also drives the separation distances and the ignition-source control that shape where duct, fans and electrical equipment can be placed.

2.5 AS 1375 — the SAA industrial fuel-fired appliances and ovens code

AS 1375 is the Australian industrial-oven and fuel-fired-appliance code and the controlling document for every cure oven in an electrical-equipment plant: the VPI dip-and-bake cure oven (120–160 degrees C), the powder-coat cure oven (180–200 degrees C), and the cast-resin cure oven (120–150 degrees C). AS 1375 sets the safe-ventilation rate inside the oven to keep any solvent off-gas below a fraction of its lower explosive limit (LEL), the purge cycle before a gas-fired burner lights, the burner-management and flame-supervision requirements, and the dedicated exhaust arrangement. For an oven-exhaust duct designer, AS 1375 forces the questions: what is the solvent loading driven off the load, what dilution air keeps the oven atmosphere safely below LEL, what is the purge volume, and how is the exhaust riser kept above its dew point so condensable solvent and resin volatiles do not pool in the duct? The answer drives the oven-exhaust riser sizing, the high-temperature material selection (309/310S above 600 degrees C, aluminised at medium temperature) and the separation of the oven riser from general facility exhaust.

2.6 AS/NZS 60079 — explosive atmospheres, the dominant electrical-safety standard

AS/NZS 60079 is the hazardous-area-classification standard. Electrical-equipment plants trigger AS/NZS 60079.10.1 (gas and vapour) and, for powder coat, AS/NZS 60079.10.2 (dust) at multiple locations:

• Zone 1: Flammable vapour likely in normal operation. The interior of a varnish dip tank and the VPI autoclave drain station during operation, the IPA wash station, the immediate envelope of an open solvent bath.
• Zone 2: Flammable vapour unlikely in normal operation, short duration. The general varnish/impregnation room, the transformer oil-filling hall around hot oil, the general solvent-handling area.
• Zone 20/21/22 (dust): Powder-coat spray booth interior and recovery collector (continuous to unlikely combustible organic dust), driving the AS 3957 dust-hazard classification.
• Special-extract (SF6): The SF6 filling, evacuation and arc-test bench — not a conventional flammable atmosphere, but a heavier-than-air asphyxiant plus corrosive toxic by-products requiring low-level extract and O2/SF6 monitoring.

AS/NZS 60079 drives Ex-rated electrical-equipment requirements for fans, motors, instrumentation, duct-mounted sensors, lighting and any electrical device inside or near the affected zones. Ductwork in the solvent-vapour and powder-coat zones must be conductive throughout (316L stainless is the default for the corrosive solvent streams, galvanised for the powder-coat dust main), continuously bonded with conductive ATEX-rated flange gaskets at every joint, externally bonded with copper or stainless bonding strap to the building earth grid, and pressure-tested with documented earth-resistance verification (less than 1 ohm to ground at every section) at commissioning. AS/NZS 60079.0 through .31 cover the equipment-protection techniques (flameproof Ex d, intrinsic safety Ex i, increased safety Ex e, pressurisation Ex p) selected against the zone.

2.7 AS 3957 — dust hazard areas for powder-coat overspray

AS 3957 is the Australian dust-hazard standard and the directly applicable document for the powder-coat line. Powder-coat overspray — epoxy, polyester or epoxy-polyester hybrid organic powder — is a combustible dust capable of deflagration. AS 3957 mandates hazard-area zoning (Zone 20 for continuous explosible-dust concentration inside the booth and collector, Zone 21 for occasional, Zone 22 for unlikely) and drives the AS/NZS 60079.10.2 electrical-equipment selection downstream. For a powder-coat duct designer, AS 3957 forces the question: at the booth and the recovery collector, what is the explosibility of the powder, what is the minimum ignition energy, what is the deflagration index, and what is the engineered deflagration-protection chain (vent panels per NFPA 68, inerting per NFPA 69, isolation valves) between the collector and the inbound duct? The answer drives the collector selection, the isolation-valve placement and the bonding-and-grounding of every metre of duct in the powder-laden circuit.

2.8 AS/NZS 1554 — structural and general welding of the enclosure steel

AS/NZS 1554 is the structural-steel welding standard governing the MIG/MAG, spot and stick welding used to fabricate switchboard and switchgear enclosures, transformer tanks and equipment frames. Welding generates iron-oxide fume, manganese fume (SafeWork WES 0.2 mg/m3 for manganese), and, on any stainless or coated steel, additional hexavalent chromium and nickel. AS/NZS 1554 sets the weld-quality requirements; the companion fume-control obligation under the WHS Regulations and SafeWork guidance drives on-tool LEV at each welding station and the duct that carries the fume to the baghouse. For the duct designer, the enclosure weld shop is a 15–20 m/s transport-velocity fume circuit feeding a baghouse with HEPA polish — conventional galvanised or aluminised spiral duct, distinct from the corrosive 316L streams elsewhere in the plant.

2.9 AS/NZS 2243.8 and AS 4024 — fume cupboards and machinery safety

AS/NZS 2243.8 governs fume cupboards in laboratory and chemistry-lab settings — the oil-test lab, the dielectric-fluid lab, the materials lab and any wet-chemistry station in an electrical-equipment plant. It sets the face-velocity requirement (typically 0.5 m/s) and the exhaust arrangement. AS 4024 (the machinery-safety series) governs guarding, access and safe design of the machinery and the duct-mounted access points — inspection ports, access doors and the safe-access provisions that the commissioning inspection verifies. Both standards shape the detail design of the LEV terminations and the duct access topology.

2.10 AS/NZS 1715 and AS/NZS 1716 — respiratory protective equipment

AS/NZS 1715 (selection, use and maintenance) and AS/NZS 1716 (RPE performance) govern the respiratory protection that backs up the engineering controls. LEV and dilution ventilation are the primary control, but the sensitiser hazards in particular — isocyanate, epoxy and acid-anhydride hardener — demand respiratory protection at the open-mould, de-gas and casting stations because the exposure target is as-low-as-reasonably-practicable rather than a comfortable margin below a numeric WES. AS/NZS 1715/1716 selection (organic-vapour cartridge, powered air-purifying respirator, supplied-air) is documented per task and forms part of the commissioning and ongoing-management record.

2.11 AS 60076 and AS 62271 — the product standards that drive the test bay

AS 60076 (the transformer series, adopting IEC 60076) and AS 62271 (the high-voltage switchgear and controlgear series, adopting IEC 62271) are not HVAC standards, but they are the product standards that govern how the finished equipment is tested — and the test bay is one of the most ventilation-intensive rooms in the plant. AS 60076 sets the temperature-rise test: the transformer is loaded to drive its windings and oil to the limiting temperature rise above a defined reference ambient (around 20 degrees C), and the bay HVAC must hold that ambient stable while the unit rejects its full copper and iron loss. AS 62271 sets the equivalent for switchgear including temperature-rise and the dielectric and short-circuit tests that generate ozone and electromagnetic noise. The HVAC designer reads these standards to size the heat-run supply and extract and to set the ozone-capture requirement around the HV test cage.

2.12 NCC Section J, ASHRAE 62.1 and ISO 9001/14001/45001

NCC Section J sets the energy-efficiency provisions for the building services — fan power limits, duct insulation, economy-cycle and heat-recovery expectations — that shape the supply-and-extract plant serving the production stages and test bays. ASHRAE 62.1 (ventilation for acceptable indoor air quality) is the international reference for outdoor-air rates in the office and clean-assembly zones. ISO 9001 (quality), ISO 14001 (environmental) and ISO 45001 (occupational health and safety) frame the management systems under which the plant operates — ISO 14001 in particular drives the SF6 closed-loop recovery and emission-monitoring obligations, and ISO 45001 the LEV-maintenance and air-monitoring records. NFPA 68 (deflagration venting) and NFPA 69 (explosion prevention) are the cross-referenced US engineering basis for the powder-coat collector explosion protection where AS guidance points to international practice.

3. Coil and winding varnish, VPI vacuum pressure impregnation and dip-and-bake cure

Varnish impregnation is the single largest fume-extraction circuit in a transformer, motor or generator plant, and the one that most often defeats a generic fabricator. Every wound component — transformer coil, motor stator, generator rotor — is impregnated with an insulating varnish to lock the windings mechanically, exclude moisture and improve dielectric and thermal performance. Two processes dominate: vacuum pressure impregnation (VPI) and dip-and-bake. Both flash off significant solvent and monomer, and both finish with a high-temperature cure oven that drives off the residual.

3.1 The varnish chemistry and the WES that controls it

Australian impregnating varnishes are predominantly polyester (often styrenated) and epoxy systems. The styrenated polyester varnishes carry styrene as both solvent and reactive monomer; the cure crosslinks the polyester through the styrene. Solvent-borne systems additionally carry xylene, toluene and white-spirit (mineral-turpentine) thinners. The controlling SafeWork workplace exposure standards are styrene 50 ppm TWA, xylene 80 ppm, toluene 50 ppm and white spirit 240 mg/m3. Styrene is the usual design driver because it is present in the largest quantity and has a relatively low WES; it is also a recognised reproductive and neurological hazard, so the engineering target is well below the numeric standard. The varnish-shop LEV and the cure-oven exhaust are sized so that the styrene concentration in the operator breathing zone sits at a small fraction (commonly one tenth) of the 50 ppm standard.

3.2 VPI vacuum pressure impregnation

VPI is the premium impregnation process for medium and large windings — power-transformer coils, large motor stators, traction motors. The dry winding is loaded into an autoclave, the autoclave is evacuated to draw air and moisture out of the winding interstices, solventless or low-solvent resin is admitted under vacuum, and then dry-gas or atmospheric pressure forces the resin deep into the winding. The winding is drained and transferred to a cure oven. The fume profile is concentrated at three points: the autoclave vacuum-pump discharge (which carries the volatiles pulled off under vacuum), the drain/transfer station (where the resin-wet winding off-gasses styrene and solvent in the open), and the cure oven. The HVAC response is a dedicated extract on the vacuum-pump discharge routed to the oven-exhaust or thermal-oxidiser stream, full enclosure of the drain/transfer station with LEV at 0.5–1.0 m/s capture velocity, and the cure-oven exhaust treated as the dominant load. The autoclave room is AS/NZS 60079 Zone 2 around the resin-handling, with the resin store an AS 1940 flammable-liquid area.

3.3 Dip-and-bake

Dip-and-bake is the higher-throughput process for smaller and medium windings — distribution-transformer coils, fractional and integral-horsepower motors. The winding is dipped into a varnish tank, withdrawn, allowed to drain, and baked. The open varnish tank is the dominant emission point — a large open surface of styrenated varnish evaporating continuously — so it is enclosed and fitted with lateral-slot or push-pull LEV across the tank surface at 0.5–1.0 m/s, and it is an AS/NZS 60079 Zone 1 envelope at the tank with the surrounding room Zone 2. The drain station and the bake oven repeat the VPI pattern. Dip-and-bake plants often run multiple dip tanks and a tunnel or batch oven in series, so the aggregate solvent LEV is substantial.

3.4 The cure oven — the heaviest single load

The cure oven is where the bulk of the solvent and styrene monomer drives off. As the impregnated winding ramps to 120–160 degrees C, the residual solvent and unreacted styrene volatilise in the first 20–40 minutes of the cycle, then the crosslinking reaction completes. The oven exhaust is governed by AS 1375: the oven must run enough dilution air to keep its internal atmosphere safely below the solvent LEL, with a purge before any gas-fired burner lights and LEL monitoring on the burner. The oven-exhaust riser is kept above the solvent dew point all the way to the discharge or thermal oxidiser so condensable styrene and resin volatiles do not pool in the duct and create a fire load. For a solvent-heavy plant, a regenerative or recuperative thermal oxidiser on the combined oven exhaust is common, both to meet the EPA emission licence and to recover heat. The first section of the oven riser runs aluminised or 309/310S stainless because of the temperature; galvanised would fume.

3.5 Wilson Transformer Company, Regal Beloit CMG and TECO Australia context

Wilson Transformer Company runs VPI and resin-impregnation on its power-transformer coils at Glen Waverley and Wodonga VIC, where coil quality directly determines the dielectric performance of grid transformers. Regal Beloit and the CMG motor brand, and TECO Australia, run dip-and-bake and VPI on motor windings across their motor manufacturing and rewind operations. Every motor rewind shop in the country — and there are many, supporting the mining, water and industrial sectors — runs a varnish-and-bake line. The varnish/cure LEV is therefore the most widely replicated fume circuit in the entire electrical-equipment sector, and the one where a fabricator who understands styrene, AS 1375 and 316L corrosion-resistant oven-riser construction wins repeat work.

4. Transformer core assembly and tanking

Transformer core assembly and tanking is, by contrast, one of the lower-fume zones in the plant — but it is not zero, and it sits adjacent to high-fume zones whose contaminants must not be allowed to migrate in. The core is built from grain-oriented electrical steel laminations, stacked and clamped; the assembled core-and-coil is lowered into the tank, the leads and bushings are connected, and the tank is prepared for oil filling. The dominant HVAC demands are general ventilation, weld-fume capture at the tank fabrication and any on-site welding, and pressure control to keep solvent and oil vapour from adjacent zones out of the clean core-assembly area.

4.1 Core assembly — minimal fume, dominant cleanliness

Core stacking itself generates little airborne contaminant — some lamination-handling particulate and the vapour from any core-plate bonding or edge-coating, but no solvent flash on the scale of the varnish shop. The HVAC priority is cleanliness and pressure relationship: the core-and-coil assembly area is held at slightly positive pressure relative to the varnish, oil and paint zones so their contaminants do not drift in and contaminate the insulation system. General ventilation per AS 1668.2 with tempered supply air maintains the environment; any localised solvent use (cleaning, bonding) gets a small dedicated LEV branch.

4.2 Tank fabrication and weld fume

The transformer tank is a heavy welded steel fabrication, and the tank-fabrication bay is a weld-fume zone under AS/NZS 1554 — iron-oxide and manganese fume (manganese WES 0.2 mg/m3) from MIG/MAG welding of the tank plate, with on-tool LEV at each welding station and a 15–20 m/s spiral fume main to a baghouse. Large power-transformer tanks may be welded in dedicated heavy-fabrication bays with overhead canopy extraction supplementing on-tool capture. The tank-paint and corrosion-protection operation (often a separate booth) adds a coating-fume LEV branch.

4.3 Tanking and lead connection

Tanking — lowering the core-and-coil into the tank and making the internal connections — is a clean operation requiring controlled environment and good general ventilation to keep dust and moisture out of the active part. Any solder or braze on the internal connections gets a local capture point. The zone abuts the oil-filling hall, so the pressure-relationship control between tanking (clean, positive) and oil-filling (vapour-bearing, neutral-to-negative) is part of the HVAC design.

5. Transformer insulating-oil filling, degassing and processing

Once tanked, a liquid-filled transformer is filled with insulating oil under vacuum and the oil is processed (degassed, dehydrated, filtered) to achieve the dielectric strength and low moisture and gas content the design requires. The oil hall is an AS 1940 combustible-liquid area with its own characteristic HVAC profile: oil mist, degassing vapour and the heat of hot-oil processing.

5.1 The insulating fluids — mineral oil and ester

Traditional transformer oil is highly refined mineral (naphthenic) oil. The market is shifting toward natural-ester (vegetable-derived) and synthetic-ester insulating fluids for their higher fire point, biodegradability and moisture-tolerance, particularly in distribution and traction applications and in fire-sensitive installations. Both mineral oil and ester are combustible liquids under AS 1940. From an HVAC standpoint, the key parameter is oil mist — the SafeWork workplace exposure standard for oil mist is 5 mg/m3 — plus the degassing vapour driven off during processing.

5.2 Oil filling under vacuum and degassing

The transformer is evacuated and oil is admitted under vacuum to exclude air and moisture from the windings and insulation. The oil is circulated through an oil-processing rig that heats it, sprays it into a vacuum chamber to strip dissolved gas and water, and filters it. The hot oil sprayed into the degassing vacuum chamber generates oil mist and vapour; the vacuum-pump discharge carries the stripped volatiles. The HVAC response is a dedicated extract on the oil-processing rig vacuum discharge and on the degassing chamber vent, with the oil hall under general ventilation sized to hold oil mist below 5 mg/m3 in the breathing zone. The oil-handling area is AS/NZS 60079 Zone 2 around hot oil and the open transfer points.

5.3 Hot-oil heat and material selection

Oil processing runs the oil at 60–90 degrees C (and the degassing chamber hotter), so the oil hall carries a thermal load that the supply-and-extract system must remove. The oil-mist and degassing-vapour extract duct runs 316L stainless because oil mist and any oxidation products are mildly corrosive and because the duct must be cleanable — oil mist accumulates and a galvanised duct becomes a maintenance and fire-load problem over time. The SBAL-V stainless line and SBSF-1525 hermetic seam give the corrosion-resistant, cleanable oil-mist extract main.

5.4 Wilson Transformer Company oil context

Wilson Transformer Company, as the country’s largest transformer maker, runs significant oil-filling and oil-processing capacity at Glen Waverley and Wodonga for its liquid-filled power and distribution transformers, including the large grid transformers that anchor the Australian transmission network. The oil hall HVAC — oil-mist extract, degassing-vapour capture, hot-oil thermal load and AS 1940 compliance — is a core part of the plant ventilation design and a recurring requirement as the sector expands transformer output to support grid electrification.

6. SF6 gas-insulated switchgear handling — asphyxiant, greenhouse gas and toxic arc by-products

Sulphur hexafluoride (SF6) handling is the most specialised and most hazardous single HVAC problem in switchgear manufacturing, and it is misunderstood often enough to be worth setting out carefully. SF6 is the insulating and arc-quenching gas used in gas-insulated switchgear (GIS), SF6 circuit breakers and ring-main units. It is favoured because of its outstanding dielectric strength and arc-interruption performance, which allow very compact high-voltage switchgear. But it presents three distinct hazards, and the HVAC system must address all three.

6.1 SF6 as a simple asphyxiant — the floor-level extract problem

Pure SF6 is chemically inert and non-toxic, but it is roughly five times heavier than air. When released — during filling, evacuation, a fitting leak or a test — it sinks and pools at floor level, in pits, trenches and low-lying confined spaces, displacing oxygen without odour or warning. An operator entering a pit where SF6 has accumulated can lose consciousness from oxygen deficiency before sensing anything wrong. The SafeWork exposure standard for SF6 itself is 1000 ppm. The HVAC response is low-level extract in every SF6 handling and test area, mechanical ventilation that sweeps the floor zone rather than just the upper room, O2 monitoring at low level and in any pit (cap 19.5–23.5 percent oxygen), and a confined-space-entry regime for trenches and pits. Floor-level extract grilles connected to a 316L stainless extract main are the standard arrangement.

6.2 SF6 as a potent greenhouse gas — closed-loop recovery, never venting

SF6 is the most potent greenhouse gas in widespread industrial use, with a global warming potential on the order of 23,500 times that of carbon dioxide over a 100-year horizon and an atmospheric lifetime of thousands of years. Under ISO 14001 environmental management and Australian emission-reporting obligations, SF6 is never vented to atmosphere. All filling and evacuation is done with closed-loop SF6 recovery carts that pump the gas into and out of the switchgear under vacuum, recompress it and store it for reuse. The HVAC system supports this by keeping the handling area ventilated for the inevitable small leaks while the gas itself is managed in the closed recovery loop — the extract handles fugitive emission and the by-product set, not bulk SF6 disposal.

6.3 SF6 arc by-products — the real toxic danger

The genuine acute-toxicity hazard arises when SF6 decomposes under an electrical arc. During routine dielectric and short-circuit testing, breaker-operation testing, or any internal arcing, SF6 breaks down and recombines into a set of acutely toxic compounds: thionyl fluoride (SOF2), sulphuryl fluoride (SO2F2), hydrogen fluoride (HF), sulphur dioxide (SO2) and various metal fluorides. HF in particular is extraordinarily corrosive and toxic — the SafeWork benchmark for HF is around 1.8 ppm and for SO2 around 2 ppm. These by-products are released when arced switchgear is opened for inspection or when a test bench arcs SF6 deliberately. The HVAC response is a dedicated low-level extract on every SF6 arc-test bench and on the switchgear-opening station, routed to an alkaline or soda-lime chemical scrubber that neutralises the HF and the fluoride by-products before discharge. The extract duct is 316L stainless or FRP because HF and the fluoride condensate corrode ordinary steel and galvanising rapidly. Operators opening arced compartments wear respiratory protection per AS/NZS 1715/1716, and the area carries continuous HF and O2 monitoring.

6.4 SF6 alternatives and the evolving picture

Driven by the greenhouse-gas concern, the industry is developing SF6-alternative insulating gases — fluoronitrile and fluoroketone gas mixtures, and vacuum interruption for medium-voltage switchgear. These alternatives change the by-product chemistry but not the fundamental HVAC principle: heavier-than-air gas demands floor-level extract, arc by-products demand scrubbed corrosion-resistant extract, and the handling area demands O2 monitoring. NOJA Power in Murarrie QLD, an Australian-grown global leader in pole-mounted reclosers, has been a notable mover toward solid-dielectric and SF6-free recloser technology; Schneider Electric Australia, ABB Australia and Siemens Australia all handle SF6 and SF6-alternative gas across their switchgear production and test operations. Terasaki and the Australian switchboard builders integrating SF6 ring-main units handle the gas in assembly and commissioning.

7. Busbar copper fabrication, silver plating and brazing

Busbar fabrication is the copper backbone of switchgear and switchboards — the current-carrying bars that distribute power inside a switchboard or substation. The busbar shop cuts, punches and bends copper bar, silver-plates the contact surfaces for low-resistance jointing, and brazes connections. It generates three distinct fume streams, two of them corrosive and one of them historically among the most toxic in all of manufacturing.

7.1 Brazing fume and the cadmium imperative

Silver-brazing copper busbar joints once used silver-brazing filler alloys that contained cadmium to lower the melting point and improve flow. Cadmium fume is one of the most dangerous occupational exposures in existence — the SafeWork workplace exposure standard for cadmium is 0.001 mg/m3, among the very lowest in the entire standard, and cadmium is a confirmed human carcinogen and a kidney toxin. For this reason, cadmium-free silver-brazing alloys are the mandatory modern standard for busbar brazing; no responsible Australian shop brazes with cadmium-bearing filler. Even with cadmium-free alloy, brazing generates metal fume (copper, silver, zinc) and the operation gets on-tool LEV at each brazing bench at 0.5–1.0 m/s capture velocity. The copper-fume WES is 0.2 mg/m3 where copper is heated.

7.2 Flux fume — corrosive fluoride and borate

Brazing flux is typically a fluoride- and borate-based paste or powder that cleans the joint and protects it during brazing. The flux fume is corrosive and irritating — fluoride compounds in particular attack ordinary steel and galvanising. The brazing-bench LEV that captures the brazing fume also captures the flux fume, and the duct carrying it runs 316L stainless or FRP because of the fluoride corrosivity. Post-braze flux residue is washed off, adding a small acid/alkali wash LEV.

7.3 Plating acid mist

Silver plating of the busbar contact surfaces — and any preceding copper or nickel strike to prepare the surface — is an electroplating operation that releases acid mist at the plating tanks as hydrogen bubbles burst at the anode and cathode. The plating line (degrease, acid pickle, strike, plate, rinse) is a wet-chemistry area with lateral-slot or push-pull LEV across each tank at 0.5–1.0 m/s, routed to a packed-bed scrubber that neutralises the acid mist before discharge. The plating-area duct is 316L stainless or, for the most aggressive acid streams, FRP with a corrosion-resistant resin. The plating line is also an AS 1940 and AS 4326 dangerous-goods area for the plating chemistry.

7.4 Cabac, NHP and Australian Switchgear busbar context

Cabac (cable accessories, connectors and busbar components), the busbar shops within NHP and Australian Switchgear, and Power & Electrical Switchgear all run busbar fabrication, plating and brazing as part of switchboard manufacturing. B&R Enclosures, primarily an enclosure maker, integrates busbar systems into its switchboard products. The fume streams — cadmium-free brazing fume, corrosive flux fume and plating acid mist — are consistent across these operations, and the corrosion-resistant 316L/FRP LEV that handles them is a recurring fabrication requirement. The SBAL-V stainless line, SBSF-1525 hermetic seam and SBFB-1500 spiral cover the busbar-shop duct envelope.

8. Sheet-metal enclosure fabrication and powder coating

Almost every piece of electrical equipment lives inside a sheet-metal enclosure — switchboard cubicles, switchgear cabinets, motor-control-centre panels, transformer kiosks, equipment frames. The enclosure shop is a sheet-metal fabrication operation (cut, punch, fold, weld) followed by a finishing line (pre-treatment, powder coat, cure). It carries two principal HVAC demands: weld fume from the fabrication, and powder-coat overspray plus cure-oven exhaust from the finishing.

8.1 Enclosure weld fume

Enclosure fabrication welds mild-steel and, increasingly, stainless and zinc-coated sheet using MIG/MAG, spot and occasionally stick welding under AS/NZS 1554. The fume is dominated by iron oxide and manganese (manganese WES 0.2 mg/m3), with hexavalent chromium and nickel added where stainless is welded and zinc fume where galvanised sheet is welded. On-tool LEV at each welding station, supplemented by bench-downdraught or overhead capture in high-throughput cells, feeds a 15–20 m/s spiral fume main to a baghouse with HEPA polish. This is a conventional weld-fume circuit — galvanised or aluminised spiral duct — distinct from the corrosive 316L streams elsewhere in the plant. B&R Enclosures, as a dedicated enclosure manufacturer, runs this at volume.

8.2 Pre-treatment line

Before coating, the enclosure steel is cleaned and conversion-coated — alkaline degrease, acid pickle or phosphate/zirconium conversion, and rinse stages. These wet-chemistry stages release acid and alkali mist that is captured by tank-side LEV and routed to a scrubber. The pre-treatment duct runs 316L stainless or FRP for the acid stages. The pre-treatment line is an AS 1940/AS 4326 dangerous-goods area for the chemistry.

8.3 Powder-coat spray booth — combustible-dust deflagration control

Powder coating is the dominant enclosure finish — durable, attractive and free of the solvent emissions of wet paint. Dry powder (epoxy, polyester or epoxy-polyester hybrid) is electrostatically sprayed onto the earthed enclosure in a spray booth, with overspray captured at the booth face and recovered through a cyclone and cartridge collector for reuse. The critical point is that the organic powder is a combustible dust: an airborne cloud of powder-coat at the right concentration can deflagrate if ignited. The booth and its recovery collector therefore fall under AS 3957 dust-hazard-area classification and AS/NZS 60079 zoning, with NFPA 68 (deflagration venting) and NFPA 69 (explosion prevention) as the cross-referenced engineering basis. Booth face velocity is 0.5–0.7 m/s — enough to capture overspray and protect the operator, but not so high as to strip powder off the part or disturb the powder cloud. The booth and collector duct must be conductive, bonded and earthed (below 1 ohm to ground) so static cannot ignite the cloud, and deflagration-isolation between the collector and the duct main prevents flame propagation. The booth-and-collector dust main is galvanised spiral (the powder is not corrosive) at 18–20 m/s transport velocity, but the bonding-and-grounding and deflagration-protection discipline is non-negotiable.

8.4 Powder-coat cure oven

After spraying, the coated enclosure passes through a cure oven that crosslinks the powder at 180–200 degrees C. The oven off-gas carries powder volatiles and crosslinker by-products. The oven is governed by AS 1375 — safe ventilation rate, purge before burner light, LEL monitoring on any gas-fired burner, and a dedicated exhaust riser separate from general extract. The oven-exhaust riser runs aluminised steel or 316L stainless because zinc fumes above 250 degrees C service, so galvanised is unsuitable for the hot riser. The cure-oven exhaust is a candidate for heat recovery given the continuous 180–200 degrees C reject heat. B&R Enclosures, NHP, Australian Switchgear and most switchboard builders run a powder-coat line with this booth-plus-oven HVAC topology.

9. Cast-resin dry-type transformer epoxy casting

Cast-resin dry-type transformers are the oil-free alternative to liquid-filled units, with the windings encapsulated in cured epoxy resin rather than immersed in oil. They are favoured where fire risk, oil-leak risk or environmental sensitivity rules out liquid-filled units — indoor substations, buildings, marine, mining and renewable-generation step-up duty. The casting process introduces a specific and serious sensitiser hazard that the HVAC system must control.

9.1 The epoxy and anhydride chemistry — sensitisers, not simple solvents

Cast-resin transformers use a two-part epoxy system: an epoxy resin (typically bisphenol-A or bisphenol-F diglycidyl ether) cured with an acid-anhydride hardener (methyltetrahydrophthalic anhydride and related anhydrides), usually with a silica filler. Both components are sensitisers. Uncured epoxy resin is a skin sensitiser causing allergic contact dermatitis. The acid-anhydride hardeners are potent respiratory sensitisers that cause occupational asthma and rhinitis at very low airborne concentration. Because sensitisation can occur at concentrations well below an irritant threshold, SafeWork treats epoxy and acid-anhydride as sensitisers for which exposure must be reduced as low as reasonably practicable rather than simply controlled to a numeric WES. This changes the engineering target: the LEV must capture essentially all of the fume at source, and respiratory protection per AS/NZS 1715/1716 backs it up at open-handling stations.

9.2 The casting process — vacuum de-gas and cure

The epoxy and anhydride are metered, mixed and de-gassed under vacuum to remove entrained air (voids in the casting are dielectric weak points), then poured into a mould around the pre-heated winding, and cured in an oven at 120–150 degrees C. The fume arises at the mixing/de-gas station (the open resin surface and the vacuum-pump discharge), at the open-mould pour, and at the cure oven (residual anhydride and epoxy volatiles). The HVAC response is full enclosure of the mixing/de-gas station with LEV at 0.5–1.0 m/s, a capture hood over the pour station, and the cure-oven exhaust to AS 1375. Where a reactive diluent or solvent thinner is used, AS/NZS 60079 zoning applies at the handling point.

9.3 Corrosion and material selection

The anhydride vapour and its condensate are corrosive — anhydride reacts with moisture to form the corresponding acid — so the cast-resin LEV and oven-exhaust duct run 316L stainless or FRP rather than galvanised. The duct must also be cleanable because resin volatiles can condense and build up. The SBAL-V stainless line and SBSF-1525 continuous-TIG seam give the corrosion-resistant, cleanable, hermetic cast-resin extract main; the SBPC1500 cuts the high-temperature oven transitions.

9.4 Cast-resin in the Australian market

Cast-resin dry-type transformers are produced and supplied by several Australian transformer makers and the local arms of the multinationals (Schneider Electric Australia, ABB Australia, Siemens Australia) as the dry-type complement to Wilson Transformer Company liquid-filled units. Demand for dry-type units is rising with building electrification, data-centre power and renewable-generation connections where fire and environmental constraints favour oil-free transformers — which makes the cast-resin casting-and-cure HVAC an expanding requirement.

10. Motor and generator manufacturing — winding, varnish, commutator and test

Motor and generator manufacturing shares much of its HVAC profile with transformer winding but adds its own operations: commutator and slip-ring work, balancing, and motor/generator test. Regal Beloit and the CMG brand, TECO Australia, and the national network of motor-rewind and generator-assembly shops all run this envelope.

10.1 Winding and insulation

Motor and generator windings are formed, inserted into the stator slots or wound onto the rotor, insulated and connected. The insulation system uses films, tapes, slot liners and resins; the operation generates limited airborne contaminant until the varnish/impregnation stage. The winding area gets general ventilation and localised capture at any solvent-using insulation step.

10.2 Varnish and impregnation — the shared styrene load

Like transformer coils, motor and generator windings are varnish-impregnated by VPI or dip-and-bake, with the same styrene, xylene and toluene chemistry and the same WES (styrene 50 ppm, xylene 80 ppm, toluene 50 ppm). Large motor and generator stators are prime VPI candidates; smaller motors run dip-and-bake. The varnish/cure LEV and AS 1375 oven exhaust described in Section 3 apply directly. For traction motors and large industrial machines the VPI autoclave and cure oven are sizeable, and the solvent LEV is correspondingly large.

10.3 Commutator, brush and slip-ring work

DC machines and wound-rotor machines have commutators and slip rings that are machined, undercut and finished. This generates fine conductive copper and carbon (brush) dust that must be captured — a localised dust LEV at the commutator-machining and brush-fitting stations, with copper-fume considerations (WES 0.2 mg/m3) where any heating occurs. Carbon brush dust is conductive and a housekeeping/insulation-contamination concern, so it is captured at source.

10.4 Balancing, assembly and test

Rotors are dynamically balanced; the assembled machine is run-tested. Motor and generator test loads the machine and, like the transformer heat-run, rejects heat — a large generator test rejects substantial heat into the test cell that the HVAC must remove. The test cell also carries the ozone consideration where high-voltage insulation testing is performed. Section 11 covers the test-bay HVAC in detail; the motor/generator test cell is a smaller-scale version of the same problem.

11. High-voltage test bay — heat-run thermal load and corona ozone

The test bay is, in many transformer, switchgear, motor and generator plants, the single most ventilation-intensive room — and it presents two unrelated HVAC problems in the same space: the thermal load of heat-run (temperature-rise) testing, and the ozone generated by high-voltage and partial-discharge testing. The product standards AS 60076 (transformers) and AS 62271 (switchgear) define the tests; the HVAC engineer reads those standards to size the bay.

11.1 The heat-run / temperature-rise test — megawatt-scale heat rejection

The temperature-rise (heat-run) test loads the unit under test at or above rated conditions for hours to verify it does not exceed its limiting temperature rise above a reference ambient. AS 60076 references a reference ambient around 20 degrees C and tight stability, so the bay HVAC must hold the ambient steady while the unit rejects its entire copper loss and iron loss as heat. The numbers are large: a medium power transformer heat-run can reject 50–300 kW continuously; a large grid transformer or a large generator test can reject upwards of 1 MW. The HVAC response is high-volume tempered supply air and a matched extract sized to remove the test heat while holding the reference ambient — effectively a large process-cooling ventilation system. Because the reject heat is continuous and at a useful temperature, the heat-run extract is a prime heat-recovery opportunity (Section 15).

11.2 Corona and ozone in the HV and partial-discharge test

High-voltage dielectric testing, induced-voltage testing and partial-discharge measurement energise the unit at test voltage. Corona discharge — the partial ionisation of air around sharp edges and high-field regions of energised conductors — converts atmospheric oxygen into ozone (O3). Ozone is a respiratory irritant with a SafeWork workplace exposure standard of 0.1 ppm, and even modest corona produces measurable ozone in an enclosed HV bay. The HVAC response is general dilution ventilation across the bay plus localised extract near the HV test cage, with the ozone-bearing extract discharged to atmosphere away from air intakes. Ozone is unstable and decays to oxygen over minutes, so the control is dilution-and-discharge rather than scrubbing; the design holds the bay ozone below the 0.1 ppm standard during testing.

11.3 Partial-discharge electromagnetic environment

Partial-discharge measurement is extremely sensitive to electrical noise, so the test bay is often electromagnetically shielded and the HVAC plant (fans, motors, VSDs) must be selected and located so it does not inject electrical noise into the measurement. This constrains where duct penetrations and fan equipment can sit and sometimes requires filtered, screened or remotely located fan plant — an HVAC design constraint that does not arise in ordinary industrial ventilation.

11.4 Test-bay HVAC across the sector

Wilson Transformer Company operates large heat-run and HV test facilities for its power and grid transformers; the multinationals and NOJA Power operate switchgear type-test and routine-test facilities; Ampcontrol type-tests its mining switchgear; the motor and generator makers run machine test cells. Across all of them, the test-bay HVAC — megawatt-scale heat rejection, ozone dilution, reference-ambient stability and partial-discharge electromagnetic constraint — is the most demanding single ventilation system in the plant and the one most worth getting right, both for test validity and for energy recovery.

12. Battery, UPS and inverter assembly

The power-electronics and energy-storage tier of the sector — uninterruptible power supplies (UPS), grid and solar inverters, EV chargers, and battery-system assembly — is growing fast on the back of renewable-energy and electrification demand. Fimer/ABB inverters, Tritium EV chargers (Brisbane), and the battery and UPS assemblers all run operations with their own HVAC profile, blending electronics assembly with high-power test.

12.1 Battery handling and thermal-runaway ventilation

Lithium-ion battery assembly and testing carries a specific hazard: thermal runaway, in which a damaged or faulty cell vents flammable and toxic gas (hydrogen fluoride, carbon monoxide, hydrocarbons, and a flammable electrolyte vapour) and can ignite. Battery assembly and formation/test areas need general ventilation plus the ability to handle a venting event — gas detection, high-rate purge extract, and segregation. The HF in vented battery gas (WES around 1.8 ppm) and the carbon monoxide (WES 30 ppm) are the toxic concerns; the flammable vapour is the fire/explosion concern. The extract serving battery formation and test runs corrosion-resistant 316L because the vented HF is corrosive.

12.2 Inverter and UPS assembly

Inverter and UPS assembly is principally electronics assembly — PCB population, soldering, enclosure assembly — with the solder-fume profile of Section 13, plus conformal-coating operations that release solvent and need LEV. Fimer/ABB inverter assembly and the UPS assemblers run this envelope.

12.3 High-power inverter and EV-charger test

Inverters, UPS and EV chargers are load-tested at high power, rejecting heat into the test area much as the heat-run bay does, though usually at smaller per-unit scale. Tritium, the Brisbane-based EV-charger manufacturer, tests high-power DC fast-chargers that reject significant heat under test; the test-area HVAC removes that heat and holds the test ambient. As DC-fast-charger power ratings climb, the per-unit test heat load climbs with them, making the test-area ventilation an expanding demand.

13. Solder and electronics fume — rosin/colophony sensitiser and lead-free

Switchgear protection relays, control electronics, inverter and UPS boards, battery-management systems and instrumentation all involve electronics assembly and soldering, so solder fume is a pervasive low-level hazard across the sector. It is easy to underestimate because the quantities are small, but the sensitiser content makes it a genuine occupational-health concern.

13.1 Rosin/colophony flux fume — the respiratory sensitiser

The dominant hazard in solder fume is not the metal — it is the flux. Rosin-based (colophony) solder flux, when heated, releases a fume of resin-acid decomposition products that is a recognised respiratory sensitiser and a leading cause of occupational asthma in electronics manufacturing. SafeWork treats rosin-based solder-flux fume as a sensitiser to be controlled as low as reasonably practicable. Even no-clean and water-soluble fluxes release irritant fume. The control is tip extraction or bench-top LEV at every soldering position, capturing the fume at the iron tip or immediately above the work, routed through a filter (particulate plus gas-phase) before recirculation or discharge.

13.2 Lead-free solder and metal fume

Modern electronics use lead-free solder (tin-silver-copper alloys) under RoHS-equivalent expectations, which removes the lead-fume hazard of older tin-lead solder but raises soldering temperatures and changes the flux activity. The metal-fume component of solder fume is minor compared with the flux fume, but the higher lead-free process temperature increases flux-fume generation, reinforcing the need for tip extraction. Hand-solder benches, rework stations and any wave or reflow soldering all get LEV.

13.3 Conformal coating and cleaning

Populated boards destined for harsh environments (mining, outdoor switchgear, EV chargers) are conformal-coated with acrylic, urethane or silicone coatings that release solvent during application and cure. Conformal-coat spray and dip stations get dedicated LEV, and where urethane coatings are used the isocyanate consideration (WES 0.02 ppm for isocyanate) applies, demanding full capture and AS/NZS 1715/1716 respiratory protection. The cleaning of boards (IPA and other solvents) adds a small flammable-solvent LEV under AS 1940.

14. Hazardous-area classification across the electrical-equipment plant

Pulling the process zones together, the hazardous-area classification of an electrical-equipment plant under AS/NZS 60079 and AS 3957 is what ties the whole ventilation design into a coherent safety case. The classification determines where Ex-rated electrical equipment is required, how the ductwork must be bonded and earthed, and where deflagration and isolation protection sits.

14.1 The gas/vapour zones (AS/NZS 60079.10.1)

The flammable-vapour zones are driven by the solvents and flammable liquids: the varnish dip tank and VPI drain station (Zone 1 at the source, Zone 2 in the surrounding room), the solvent and varnish store (Zone 1/2 per AS 1940), the IPA and cleaning-solvent stations (Zone 1 at the bath), the transformer oil-filling hall (Zone 2 around hot oil and open transfer), and any reactive-diluent cast-resin handling (Zone 1/2). Each zone dictates the electrical-equipment protection technique for fans, motors, sensors and lighting in and around it, and dictates that the duct serving it is conductive, bonded and earthed.

14.2 The dust zones (AS 3957 and AS/NZS 60079.10.2)

The combustible-dust zone is the powder-coat booth and its recovery collector (Zone 20 inside the collector and booth plenum, Zone 21/22 around them), classified under AS 3957 with the AS/NZS 60079.10.2 electrical selection following. The deflagration-protection chain — NFPA 68 venting, NFPA 69 prevention/inerting, isolation between collector and duct — is engineered against the powder’s explosibility.

14.3 The SF6 special case

SF6 handling is not a conventional AS/NZS 60079 flammable atmosphere, but it is a recognised hazardous zone of its own kind — heavier-than-air asphyxiant plus corrosive toxic by-products. It is managed with floor-level extract, O2 and HF/SF6 monitoring, scrubbed corrosion-resistant extract and confined-space-entry control. The hazardous-area drawing set records the SF6 zones alongside the AS/NZS 60079 gas and dust zones so the whole plant has one integrated classification.

14.4 Ductwork bonding and earthing

Across every hazardous zone, the ductwork must be conductive throughout, continuously bonded with conductive ATEX-rated flange gaskets at every joint, externally bonded with copper or stainless strap to the building earth grid, and verified at commissioning to less than 1 ohm to ground at every section. This is what prevents a static discharge from igniting a solvent-vapour atmosphere or a powder-coat cloud. The bonding-and-earthing verification, joint by joint, is part of the commissioning record and the AS/NZS 60079 compliance documentation.

15. Dilution-ventilation calculation against the workplace exposure standards

The quantitative heart of electrical-equipment-plant ventilation design is the dilution-and-capture calculation against the controlling workplace exposure standard for each contaminant. AS 1668.2 sets out the dilution method; the SafeWork WES values set the targets. This section sets out the approach and the controlling numbers.

15.1 The capture-at-source principle

The first principle is that LEV captures the contaminant at source — at the varnish tank, the oven hood, the brazing bench, the plating tank, the powder-coat booth, the SF6 bench, the solder tip — before it disperses into the room. Capture velocities run 0.5–1.0 m/s for most fume sources, 0.3–0.5 m/s for enclosed cabinet apertures, and higher at welding arcs. LEV is far more effective and far cheaper to run than diluting a fully dispersed contaminant, so it does the bulk of the work; dilution ventilation is the backstop that handles fugitive escape.

15.2 The dilution backstop and the WES targets

Dilution ventilation is sized so that the residual contaminant that escapes capture is diluted to well below its WES in the breathing zone — commonly to one tenth of the WES as a design margin. The controlling SafeWork workplace exposure standards across the plant are:

• Styrene 50 ppm (VPI/dip varnish) — usually the design driver in the winding shop.
• Xylene 80 ppm and toluene 50 ppm (varnish/solvent thinners).
• White spirit 240 mg/m3 (mineral-turpentine thinner).
• Isocyanate 0.02 ppm (urethane conformal coat / some resins) — one of the lowest standards, demands full capture.
• Epoxy and acid-anhydride (cast resin) — sensitisers, control as low as reasonably practicable.
• Oil mist 5 mg/m3 (transformer oil processing).
• Ozone 0.1 ppm (HV/partial-discharge test corona).
• SF6 1000 ppm, with arc by-products HF 1.8 ppm, SO2 2 ppm and SOF2 controlled with the fluoride set.
• Cadmium 0.001 mg/m3 (brazing — eliminated by using cadmium-free alloy) and copper fume 0.2 mg/m3.
• Manganese 0.2 mg/m3 and the weld-fume set (enclosure fabrication, tank welding).
• Rosin/colophony solder-flux fume — sensitiser, control as low as reasonably practicable.
• Carbon monoxide 30 ppm and carbon dioxide 5000 ppm (combustion, battery vent, general air quality).

15.3 Worked logic for a varnish cure oven

For a VPI cure oven, the AS 1375 oven-ventilation rate is set first — enough dilution air inside the oven to keep the solvent off-gas below a safe fraction of its LEL during the peak off-gassing period. That oven-exhaust flow, kept above the solvent dew point, is then the dominant solvent extract; the workshop dilution ventilation is sized so that any styrene escaping the oven loading aperture and the drain station is held below one tenth of the 50 ppm styrene WES in the operator zone. The two calculations — oven LEL-safety dilution and workshop WES dilution — together fix the varnish-shop ventilation rate, and the commissioning air-monitoring verifies the breathing-zone result against the WES.

15.4 Coincidence and turn-down

Because not every source runs at once, the plant extract main is sized on a coincidence factor — the realistic simultaneous load of the branches — rather than the arithmetic sum of every branch at full flow. Variable-speed drives on the fans, interlocked to the process equipment, turn the extract down when sources are idle, saving fan energy (an NCC Section J expectation) while ensuring full flow whenever a source is active. The control logic ties the LEV demand to the actual process state, so the varnish-shop extract ramps up when the dip line and oven are running and turns down out of production.

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

Galvanised duct is the workhorse of HVAC fabrication. Across data centres, commercial towers, hospitals and schools, hot-dip-galvanised carbon steel sheet to AS/NZS 4254 is the right answer for the bulk of duct work. In an electrical-equipment plant, it is the right answer for the supply air, the general extract, the weld-fume mains and the powder-coat dust main — but the wrong answer for the corrosive and high-temperature streams. Material selection across the plant follows the contaminant.

16.1 Galvanised carbon steel — where it works and where it fails

Galvanised carbon steel works for the supply-air system, the office and clean-assembly ventilation, the enclosure weld-fume mains (iron oxide and manganese are not corrosive to zinc) and the powder-coat overspray dust main (organic powder is not corrosive). It fails on three streams. First, temperature: zinc fumes above 250 degrees C service and volatilises above 419 degrees C, so the VPI, powder-coat and cast-resin cure-oven hot risers and the heat-run high-temperature sections cannot use galvanised. Second, corrosion: HF and SOF2 from SF6 arc by-products, plating-acid mist, fluoride brazing flux, anhydride condensate and oil-mist oxidation products all attack zinc. Third, cleanability: streams that condense (oil mist, resin volatiles) build up in galvanised duct and become a maintenance and fire-load problem.

16.2 316L stainless — the corrosive-stream workhorse

316L stainless (Cr 16–18 percent, Ni 10–14 percent, Mo 2–3 percent, C at or below 0.03 percent) is the dominant material for the corrosive and cleanable streams: varnish-solvent LEV, transformer oil-mist extract, SF6 arc by-product extract, cast-resin anhydride extract, busbar plating-acid and flux-fume mains, and battery-vent extract. The molybdenum gives the chloride- and acid-corrosion resistance that 304 lacks, and the low carbon allows continuous welding without sensitisation. The SBAL-V auto duct line with stainless option produces 316L rectangular duct at 4–6 m/min on 1.0 mm gauge; the SBFB-1500 spiral tubeformer produces 316L round duct from 80 mm to 1500 mm diameter; the SBSF-1525 longitudinal stitch welder lays a continuous TIG bead for a hermetic, corrosion-resistant, cleanable seam.

16.3 309/310S high-temperature stainless and aluminised steel

For the cure-oven and heat-run high-temperature risers above 600 degrees C continuous, 316L exceeds its safe service temperature and 309/310S high-temperature stainless (Cr 22–25 percent, Ni 12–20 percent) extends service to around 1100 degrees C. In practice the cure ovens in this sector run 120–200 degrees C, comfortably within aluminised-steel territory (service 400–600 degrees C), so aluminised steel is the practical and economical choice for most cure-oven risers, with 309/310S reserved for any higher-temperature application. The SBPC1500 plasma cutter cuts both 309/310S and the transitions; the SBAL-III heavy-gauge line forms the bulk medium-temperature riser.

16.4 FRP fibreglass-reinforced plastic — aggressive acid and HF service

For the most aggressive acid streams — HF-bearing SF6 by-product extract, the strongest plating-acid mist, fluoride flux fume — even 316L is attacked slowly, and FRP fibreglass-reinforced plastic with a corrosion-resistant resin (vinyl ester or furan) is the preferred material. FRP duct is built to AS/NZS 4254 with manufacturer-specific pressure and temperature ratings, with a conductive interior coating where AS/NZS 60079 hazardous-area zoning is in effect so the bonding-and-earthing requirement is still met.

17. The SBKJ machine line for electrical-equipment-plant duct fabrication

For an Australian fabricator or mechanical-services contractor serving the electrical-equipment sector from a base in Box Hill North VIC, the SBKJ machine envelope covers the full duct demand — from 316L corrosive-fume LEV to galvanised supply air to high-temperature oven risers. SBKJ Group manufactures and supplies the duct-fabrication machinery; the contractor uses it to fabricate the duct. The machines and their duct-fabrication roles are:

• SBAL-V auto duct line with 316L stainless option — the primary line for 316L corrosive-fume LEV (varnish solvent, oil mist, SF6 by-products, cast-resin anhydride, plating acid) and for galvanised supply air and general extract. Production envelope 0.7–1.6 mm in 304/316L plus galvanised and aluminised, with TDF flange forming. 316L production at 4–6 m/min on 1.0 mm.
• SBAL-III heavy-gauge auto duct line — heavy-gauge 1.6–2.0 mm work for the cure-oven and heat-run medium-temperature mains in aluminised and 316L, the transformer-tank weld-fume canopy mains, and the heavy enclosure-fabrication extract.
• SBSF-1525 longitudinal stitch welder — continuous TIG longitudinal seam for the hermetic corrosion-resistant envelope on varnish, oil, SF6, cast-resin and plating LEV, and for AS 1530.4 fire-rated 316L penetrations through fire compartments.
• SB-ZF1500 longitudinal stitch welder — in-line continuous longitudinal seam on spiral mains 1000–1500 mm for the corrosive-fume and high-temperature streams, operating with the SBFB-1500.
• SBFB-1500 spiral tubeformer — spiral round duct 80–1500 mm diameter for the powder-coat overspray dust main, the enclosure and tank weld-fume mains, the oil-mist and SF6 extract mains, and general round extract. The most-used machine for fume and dust mains in the plant.
• SBPC1500 plasma cutter — custom transitions in 316L, 309/310S and high-temperature stainless for the VPI, powder-coat, cast-resin cure ovens and the heat-run high-temperature exhaust, plus oven-hood cones and bellows expansion-joint flanges. Around 1.2 m/min on 1.5 mm 316L.
• SBLR-600 lock former — Pittsburgh lock and snap-lock longitudinal seams in rectangular duct, with heavy-gauge tooling for 1.2 mm 316L corrosive-fume and supply-air construction.
• SBTF-1500/1602/2020 spiral former — spiral trunk mains 1500–2000 mm for the large heat-run test-bay supply and extract trunks, the central solvent-extract trunk and the powder-coat collector trunk.

The combined machine fit delivers the production envelope to cover every duct requirement across every Australian electrical-equipment operator — Wilson Transformer Company in Glen Waverley and Wodonga VIC, NHP in Richmond VIC, NOJA Power in Murarrie QLD, Ampcontrol in Newcastle NSW, B&R Enclosures, Schneider Electric Australia, ABB Australia, Siemens Australia, Cabac, Terasaki, Australian Switchgear, Power & Electrical Switchgear, Tritium in Brisbane, Fimer/ABB, Regal Beloit/CMG, TECO Australia and Gibson Engineering. SBKJ supplies the machine; the Australian contractor fabricates the duct locally for the customer plant.

18. Commissioning, measurement and verification

Commissioning is where the fabricated ductwork becomes a verified, compliant ventilation system, and in the electrical-equipment sector the commissioning record is part of the plant’s ongoing regulatory and insurance position. Commissioning, measurement and verification (M&V) spans airflow balance, contaminant verification, bonding-and-earthing verification, and the documentation pack.

18.1 Airflow balance and pressure relationships

Each LEV branch is balanced to its design capture velocity, the extract mains to their design transport velocity, and the supply air to match the extract while holding the design pressure relationships — clean assembly and core-build positive, varnish/oil/solvent zones neutral-to-negative, so contaminant flows from clean to dirty and not the reverse. The balance is measured with calibrated instruments and recorded branch by branch. AS 4254 pressure-testing to 1.5x design pressure for 30 minutes on every branch verifies the construction leakage class.

18.2 Contaminant verification against the WES

The proof of the ventilation design is breathing-zone air monitoring against the controlling WES — styrene at the varnish line, oil mist at the oil hall, ozone in the HV test bay, HF and SF6 in the gas bay, manganese at the weld stations, solder-flux fume at the electronics benches. A NATA-accredited laboratory samples the breathing zone under representative operation and certifies the result against each WES. Quarterly (or as the risk demands) repeat sampling under AS 4801/ISO 45001 confirms ongoing performance.

18.3 Bonding, earthing and deflagration verification

In every hazardous zone, earth-bonding resistance is verified joint by joint with a hand-held meter (below 1 ohm to ground), conductive flexible connections are conductivity-tested, and the powder-coat deflagration-isolation and the solvent-zone Ex equipment are verified against the AS/NZS 60079 and AS 3957 classification. This verification is the core of the hazardous-area compliance documentation.

18.4 The documentation pack

Every length of ductwork is delivered with its mill certificate, fabrication date, pressure-test record, earth-bonding verification and AS/NZS-compliant labelling. The commissioning report ties every branch back to its AS/NZS 60079 zone or AS 3957 dust-hazard rating, its AS 1375 oven classification, its AS 1940 flammable-liquid association and its controlling WES, with the NATA-certified balance and air-monitoring results. This pack is the bridge between the fabricated duct and the operator’s ISO 9001/14001/45001 management systems and their regulatory and insurance obligations.

19. Energy, test-bay heat recovery, Green Star and NABERS

Electrical-equipment plants are energy-intensive — the cure ovens, the heat-run test bays, the dust and fume extract fans, and the make-up-air tempering all draw significant energy. NCC Section J sets the efficiency floor, but the larger opportunity is heat recovery, and the larger reputational driver is Green Star and NABERS performance.

19.1 Heat recovery from the heat-run test bay

The heat-run test bay is the standout heat-recovery opportunity in the plant. A transformer or generator under temperature-rise test rejects its full copper and iron loss — 50 kW to over 1 MW — continuously for hours, into an extract stream at a useful temperature. Rather than dumping that heat to atmosphere and separately heating other parts of the plant, a run-around coil, plate heat exchanger or heat-pump recovery on the heat-run extract can preheat make-up air, provide space heating for the winding and assembly halls, or temper the cure-oven supply. The continuous, predictable nature of the test load makes the recovery economics attractive, and the recovered heat directly offsets the gas or electric heating elsewhere.

19.2 Cure-oven heat recovery

The VPI, powder-coat and cast-resin cure ovens reject heat continuously at 120–200 degrees C. Where the oven exhaust passes through a thermal oxidiser (for solvent destruction), a recuperative or regenerative oxidiser recovers much of the combustion and process heat back into the oven supply. Even without an oxidiser, an air-to-air heat exchanger on the oven exhaust preheats the oven make-up or adjacent space heating. The recovery must respect the solvent-condensation and fire-load constraints — the recovery surface is kept above the solvent dew point — but the energy available is substantial.

19.3 Fan energy and demand-controlled ventilation

The extract fans are the continuous electrical load. Variable-speed drives interlocked to process state (Section 15.4) turn extract down when sources idle, and demand-controlled make-up-air tempering follows the extract. NCC Section J caps fan power and requires the insulation, sealing and economy-cycle measures that hold the running cost down. High-efficiency fans, low-pressure-loss duct design (the streamlined spiral geometry from the SBFB-1500 helps here) and tight ductwork (the hermetic SBSF-1525 seam reduces leakage) all reduce the fan energy.

19.4 Green Star and NABERS

Green Star (the Green Building Council of Australia’s rating) and NABERS (the National Australian Built Environment Rating System) increasingly apply to industrial and manufacturing facilities, particularly new build and major refurbishment. The HVAC design contributes to the rating through energy efficiency (heat recovery, demand control, fan efficiency), indoor environment quality (effective contaminant control and tempered make-up air) and the documented commissioning that demonstrates performance. An electrical-equipment maker pursuing a Green Star rating or a NABERS Energy commitment leans on the ventilation design to deliver both the safety outcome and the energy outcome.

20. Accessibility and amenity — DDA and AS 1428.1

The Disability Discrimination Act and the access provisions of AS 1428.1 (design for access and mobility) apply to the office, amenity and accessible areas of an electrical-equipment plant. While the production-floor ventilation is driven by the process hazards, the office, control-room, training and amenity spaces are governed by the comfort-ventilation and indoor-air-quality expectations of AS 1668.2 and ASHRAE 62.1, and their layout and access by AS 1428.1. The HVAC design coordinates duct routing, diffuser placement and plant access so that the accessible paths, accessible amenities and accessible workstations required under DDA and AS 1428.1 are not compromised by ducting, plant or noise. In practice this means the production-zone duct and plant are coordinated against the accessible-design requirements of the office and amenity envelope, so the building meets both its occupational-hazard obligations and its accessibility obligations.

21. Grid electrification, renewables and EV-charging — the demand trend

The Australian electrical-equipment manufacturing sector is in a sustained growth phase driven by the energy transition, and that growth directly expands the HVAC duct demand this guide addresses. Three forces drive it.

21.1 Grid electrification and transmission build-out

Australia’s transition from coal to renewable generation requires a vast expansion and rebuild of the transmission and distribution network — new transmission lines, new and upgraded substations, and a great many new transformers and switchgear assemblies. Wilson Transformer Company and the switchgear makers are scaling output to meet this demand, which means more winding and varnish capacity, more oil-processing capacity, more switchgear assembly and test, and therefore more varnish-LEV, oil-mist-extract, SF6-handling and test-bay HVAC. Energy Networks Australia, the peak body for the transmission and distribution networks, frames the scale of the network investment that pulls this manufacturing demand.

21.2 Renewable generation and power electronics

Solar, wind and battery generation connect to the grid through inverters, transformers (including cast-resin dry-type step-up units) and switchgear. The inverter and power-electronics tier — Fimer/ABB and others — grows with renewable deployment, expanding the solder-fume, conformal-coat and high-power-test HVAC demand. Grid-scale battery storage expands the battery-assembly and thermal-runaway-ventilation demand.

21.3 Electric-vehicle charging

The roll-out of EV charging infrastructure expands manufacturing of DC fast-chargers and the associated switchgear and transformers. Tritium, the Brisbane EV-charger maker, exemplifies this tier — high-power electronics assembly and high-power test, both with their own HVAC demand. As charger power ratings climb, the per-unit test heat load and the assembly volume climb with them.

21.4 What the trend means for duct demand

For an Australian duct fabricator, the net effect is a structural increase in demand for the specialised electrical-equipment-plant ventilation this guide describes — corrosive 316L fume LEV, high-temperature oven risers, SF6-handling extract, megawatt-scale test-bay HVAC and powder-coat dust collection — as the sector expands to electrify the grid, connect renewables and build charging infrastructure. The fabricator equipped to serve this sector with the right machine fit and the right standards knowledge is positioned for sustained work.

22. Industry bodies and the regulatory ecosystem

The electrical-equipment manufacturing sector sits within a defined ecosystem of industry bodies, regulators and standards organisations that shape both the product and the plant.

NECA (the National Electrical and Communications Association) is the peak body for the electrical contracting and electro-technology industry, representing the contractors who install and connect the switchgear, transformers and switchboards the sector manufactures. Energy Networks Australia is the peak body for the electricity transmission and distribution networks and the gas distribution networks, framing the network investment that drives transformer and switchgear demand. The EESS (Electrical Equipment Safety System) is the national framework regulating the safety of in-scope electrical equipment sold in participating Australian states, setting the registration and compliance regime for electrical products. SafeWork Australia sets the model WHS laws and the workplace exposure standards that govern the plant ventilation. Standards Australia publishes the AS/NZS standards, and the international bodies IEC (adopted into AS 60076 and AS 62271) and ISO frame the product and management-system standards. The state environment protection authorities license the plant emissions — solvent destruction, scrubber discharge, weld-fume and powder-coat stack emissions — that the HVAC system must meet. Together these bodies define the compliance landscape within which an electrical-equipment plant and its ventilation operate.

23. Competitive positioning — why the right machine fit wins this sector

The electrical-equipment manufacturing sector is unforgiving to a generic commercial duct fabricator. The varnish-solvent LEV demands styrene knowledge and 316L corrosion-resistant construction; the SF6 bay demands HF-resistant scrubbed extract; the powder-coat line demands AS 3957 deflagration discipline; the cast-resin shop demands sensitiser-grade capture; the test bay demands megawatt-scale heat handling and ozone control. A fabricator who treats any of these as ordinary galvanised duct loses money on the first job and walks away from the second — which is exactly the gap a well-equipped Australian fabricator can fill.

The competitive position for an Australian fabricator is built on three things. First, the standards knowledge to engineer to AS 1668.2, AS/NZS 60079, AS 1375, AS 1940, AS 3957, AS/NZS 1554 and the AS 60076/AS 62271 test-bay context. Second, the material discipline to use 316L, 309/310S, aluminised and FRP correctly against each stream. And third — the part SBKJ supplies — the machine fit to fabricate all of it efficiently in-house: the SBAL-V and SBAL-III duct lines, the SBSF-1525 and SB-ZF1500 continuous-seam welders, the SBFB-1500 and SBTF spiral formers, the SBPC1500 plasma cutter and the SBLR-600 lock former. A fabricator with that machine envelope can quote the whole plant — supply air, corrosive LEV, oven risers, dust collection and test-bay HVAC — from one shop, fabricate it to the right material and standard, and deliver it commissioned and documented. That is the position that wins repeat work from Wilson Transformer Company, NHP, NOJA Power, Ampcontrol and the multinationals’ Australian operations.

24. Standards reference table

The following table consolidates the standards stack for electrical-equipment manufacturing HVAC ductwork, for inclusion in design and handover documentation:

Standard / Code	Scope	Application in the plant
AS 1668.1	Fire aspects of air-handling	Smoke management, fire dampers, fire-mode shutdown
AS 1668.2	Mechanical ventilation & dilution	General ventilation, WES dilution sizing, make-up air
AS 4254.1 / .2	Sheet-metal & flexible duct construction	Duct gauge, joints, stiffeners, leakage class
AS 1530.4	Fire-resistance of building elements	250 degrees C / 2 hour fire-rated penetrations
AS 1682	Fire dampers	Damper rating at fire-compartment boundaries
AS 1940	Flammable & combustible liquids	Varnish, solvent, insulating oil, IPA storage
AS 1375	Industrial ovens & fuel-fired appliances	VPI, powder-coat, cast-resin cure ovens
AS/NZS 60079	Explosive atmospheres / hazardous area	Solvent-vapour Zone 1/2, powder-coat Zone 20/21/22, Ex equipment
AS 3957	Dust hazard areas	Powder-coat overspray deflagration zoning
AS/NZS 1554	Structural & general welding	Enclosure and transformer-tank weld-fume control
AS/NZS 2243.8	Fume cupboards	Oil-test and chemistry-lab extraction
AS 4024	Machinery safety	Guarding, duct access ports, safe access
AS/NZS 1715 / 1716	Respiratory protective equipment	RPE for sensitiser and powder tasks
AS 60076	Power transformers (IEC 60076)	Temperature-rise test ambient — heat-run HVAC driver
AS 62271	HV switchgear & controlgear (IEC 62271)	Switchgear test — ozone & heat-run HVAC driver
NCC Section J	Energy efficiency	Fan power, insulation, heat recovery
ASHRAE 62.1	Ventilation for indoor air quality	Office and clean-assembly outdoor-air rates
ISO 9001 / 14001 / 45001	Quality / environmental / OHS management	SF6 recovery, LEV maintenance, air-monitoring records
NFPA 68 / 69	Deflagration venting / explosion prevention	Powder-coat collector explosion protection (cross-ref)

The table is a reference, not a substitute for design to the current edition of each standard. Standards bodies include Standards Australia (the AS/NZS publisher), the IEC (the international electrotechnical standards adopted into AS 60076 and AS 62271), ISO (the management-system and broader standards), SafeWork Australia (the model WHS laws and workplace exposure standards), and the NFPA (the US deflagration and explosion-prevention references). The state environment protection authorities set the emission-licence conditions the HVAC discharge must meet.

25. Compliance checklist for electrical-equipment-plant duct fabrication and commissioning

A short-form compliance checklist for electrical-equipment-plant ductwork commissioning, suitable for inclusion in handover documentation:

• AS 1668.2 mechanical ventilation — design extract and make-up air calculations documented for every zone, with WES dilution sizing.
• AS 4254 duct construction — pressure-test certificates at 1.5x design pressure for 30 minutes on every duct branch.
• AS 1530.4 fire resistance — fire-rated penetrations certified at 250 degrees C / 2 hour at every fire-compartment boundary, with AS 1682 dampers.
• AS/NZS 60079 hazardous-area classification — documented Zone 1/2 (solvent vapour) and Zone 20/21/22 (powder-coat dust) maps with Ex equipment selection.
• AS 3957 dust hazard areas — documented dust hazard analysis for the powder-coat booth and collector with deflagration-protection chain.
• AS 1940 flammable and combustible liquids — varnish, solvent, insulating oil and IPA storage documented, bunded and segregated.
• AS 1375 industrial ovens — LEL safety ventilation, purge cycle and burner management documented for every VPI, powder-coat and cast-resin cure oven.
• AS/NZS 1554 welding — documented on-tool extraction at enclosure and transformer-tank weld stations.
• AS/NZS 2243.8 fume cupboards — documented face velocity and exhaust path for oil-test and chemistry-lab stations.
• AS/NZS 1715 / 1716 RPE — respiratory protection selection documented for sensitiser (epoxy, anhydride, isocyanate, rosin) and powder tasks.
• AS 60076 / AS 62271 test context — heat-run reference-ambient and ozone-control HVAC documented for the test bay.
• NCC Section J / heat recovery — fan power, insulation, demand control and test-bay/oven heat recovery documented.
• NFPA 68 / 69 — deflagration venting and explosion prevention documented for the powder-coat collection system.
• Bonding and earthing — resistance below 1 ohm to ground verified joint by joint in every hazardous zone, conductive flexible connections tested.
• ISO 9001 / 14001 / 45001 — LEV maintenance records and quarterly breathing-zone air-sampling against each WES.
• NATA certification — final commissioning balance and breathing-zone sampling certified by a NATA-accredited laboratory.

Compliance documentation forms the bridge between the fabricated ductwork and the operator’s ongoing regulatory obligation. Every length of ductwork SBKJ-equipped fabricators supply to an Australian electrical-equipment plant is delivered with mill certificate, fabrication date, pressure-test record, earth-bonding verification at every flange, and AS/NZS-compliant labelling — the foundation paperwork the operator integrates into its ISO and EESS compliance pack.

26. Closing — SBKJ engineering support for Australian electrical-equipment manufacturing

The Australian switchgear, transformer, motor and generator manufacturing sector is expanding to electrify the grid, connect renewable generation and build charging infrastructure, and every step of that expansion exposes the limits of generic commercial HVAC and demands purpose-engineered ductwork that meets the full standards stack outlined in this guide. The SBKJ Group engineering team in Box Hill North VIC is positioned to support Australian fabricators and mechanical-services contractors serving the sector with a combination of machine supply (SBAL-V, SBAL-III, SBSF-1525, SB-ZF1500, SBFB-1500, SBPC1500, SBLR-600, SBTF-1500/1602/2020), engineering documentation, commissioning support and ongoing technical advisory across every process zone described in this document — from VPI varnish-solvent LEV to SF6-handling extract to megawatt-scale heat-run test-bay HVAC.

We will be exhibiting at ARBS 2026 in Sydney in May with the full SBKJ machine portfolio plus electrical-equipment-specific reference samples covering 316L corrosion-resistant solvent and SF6-by-product LEV, high-temperature cure-oven risers, powder-coat dust-collection spiral, and test-bay heat-recovery duct. Pre-show meetings with Australian electrical-equipment fabricators, switchboard builders and mechanical contractors are scheduled across the week.