Hydrogen Production, Electrolyser, H2 Refuelling, Green Ammonia, Methanol & Renewable Hydrogen Hub HVAC Duct Guide

1. Why hydrogen production HVAC duct is the hardest brief on an Australian engineer's desk

Of every industrial vertical the SBKJ Group Box Hill North VIC engineering bench supports, the hydrogen production, electrolyser, H2 refuelling, green ammonia, green methanol and renewable hydrogen hub scope is the most demanding combination of explosion risk, toxic gas exposure, materials sensitivity, code overlap and project schedule pressure that an Australian consulting engineer is asked to navigate. The HVAC duct is not a back-of-house comfort service inside the electrolyser hall. It is the primary safety-critical layer of protection sitting between a credible hydrogen leak and a confined-space deflagration that would write off the plant, the operator's safety case and, on a bad day, the lives of the commissioning crew. Get the duct material wrong, the air change rate light, the ATEX detector grid loose or the vent stack separation short and the plant cannot be commissioned. The operator's safety case is not approvable by SafeWork or the WHS regulator. The ARENA Hydrogen Headstart milestone audit fails. The whole project sits idle on the critical path while imported electrolyser stacks sit in their crates on the laydown yard accruing demurrage at five figures per week.

The fundamental physics is hostile. Hydrogen has a lower explosive limit of 4 percent by volume in air and an upper explosive limit of approximately 75 percent — a flammable envelope four times wider than methane and ten times wider than petrol vapour. The minimum ignition energy is 0.017 millijoules, roughly one twelfth of methane and an order of magnitude below the static discharge that an unbonded operator in synthetic high-vis clothing produces during normal movement. The relative vapour density is 0.0695 with air taken as 1, meaning a hydrogen leak rises straight to the highest point of any enclosed space — exactly where Australian commercial HVAC engineers have, for decades, been comfortable routing trunk runs, plenum returns and electrical conduit. The flame velocity is 2 to 3 metres per second and the flame itself is invisible in daylight with very low radiant heat to skin, so an undetected hydrogen flame can stand on a flange face for minutes before anyone walking past notices the shimmer. Combine these properties with autoignition at 500 degrees Celsius, the fact that hydrogen molecules leak through joints and elastomer seals that contain natural gas without issue, and the extraordinary diffusivity that lets it permeate weld pinholes invisible to dye-penetrant testing, and the design margin compresses to nothing.

The Australian national framework now sits behind a 2030 production cost target of less than 2 USD per kilogram under the National Hydrogen Strategy 2024 update, with Hydrogen Headstart and the Australian Clean Hydrogen Industrial Hubs Program funding the first wave of gigawatt-scale electrolyser and ammonia exporters. The Hunter Valley Hydrogen Hub HVHH partnership between Origin Energy and Orica, the Central Queensland Hydrogen Project CQ-H2 at Aldoga led by Stanwell with Hyundai as off-take partner, the Yara Pilbara YURI Project on the Burrup Peninsula with Engie and Mitsui, the ATCO Clean Energy Innovation Hub at Jandakot WA, Fortescue Future Industries' Pilbara and Williamtown sites, AGL's Loy Yang and Hunter Valley scopes, Iberdrola Australia's Port Augusta SA and Capital Wind sites, and the proposed Bell Bay TAS, Port Hedland WA, Port Bonython SA and Eyre Peninsula SA terminals form the FEED-and-EPC pipeline that defines Australian HVAC duct demand from 2026 through 2032. Every one of these projects sits inside an envelope where AS/NZS 60079 Class I Zone 0/1/2 hazardous area, NFPA 2 Hydrogen Technologies Code, ISO 22734 electrolyser type-test, ISO 19880 fuelling station design and ISO 14687 fuel quality for FCEV off-take dominate the mechanical specification.

SBKJ Group's response from Box Hill North VIC is a fabrication and machine-supply offer matched to the standard stack. The SBAL-V auto duct production line in 316L stainless configuration, the SBAL-III third-generation auto line, the SBSF-1525 stitchwelder, the SB-ZF1500 stainless plenum press, the SBFB-1500 spiral tubeformer, the SBPC1500 plasma cutter, the SBLR-600 manual welder and the SBTF-1500, SBTF-1602 and SBTF-2020 spiral tubeformers cover the entire ductwork bill-of-quantities for an Australian hydrogen, electrolyser, HRS, green ammonia and methanol project — from the cell stack manifold collector through to the vent stack riser, the canopy ventilation drop, the tube trailer loading bay exhaust and the laboratory fume hood duct. The sections below work through the production technology, the standards stack, the materials regime and the machine configuration that delivers the scope.

2. The Australian operator portfolio — who is building what, and where

Australian hydrogen demand splits cleanly across producers, infrastructure operators and off-take customers. The producer portfolio is anchored by Fortescue Future Industries FFI, the green hydrogen and green ammonia business unit of the Andrew Forrest mining group, with scope across Pilbara WA, Williamtown NSW, the Iron Bridge and Solomon Hub mining decarbonisation projects and a Future Energy program targeting full decarbonisation of the iron ore operation. Fortescue's HVAC scope on the production side is large — gigawatt-class alkaline and PEM electrolyser halls, ammonia synthesis loops, hydrogen refuelling stations for the heavy-vehicle mining fleet, and the supporting workshop and control building scope at remote inland sites with summer ambient above 45 degrees Celsius.

ATCO Australia operates the Jandakot WA hydrogen refuelling station, the Clean Energy Innovation Hub at Jandakot and the broader WA Hydrogen Strategy delivery program. AGL Energy ASX listed AGL is delivering the Hunter Valley Hydrogen Hub on the existing Liddell rebuild precinct, with parallel scope at Loy Yang in the Latrobe Valley VIC including a green methanol and SAF pathway. Origin Energy ASX listed ORG is the Hunter Valley Hydrogen Hub HVHH partner alongside Orica, with scope also at the Eraring site as part of the coal retirement and repurposing pathway. Stanwell, the Queensland government-owned generator, leads the Central Queensland Hydrogen Hub CQ-H2 at Aldoga with Hyundai Motor Company as the named off-take partner and Iwatani Corporation as the liquid hydrogen export carrier customer. Iberdrola Australia operates the Capital Wind, Bodangora and Port Augusta SA sites with green hydrogen scope. Engie Australia runs the Stockmans Way Macquarie Park NSW hydrogen refuelling station and the Macquarie Energy renewable portfolio plus the YURI Project partnership with Yara at the Pilbara.

On the heavy-vehicle and mobility side Hyzon Motors operates the Australian heavy-vehicle H2 demonstration scope. H2X Global is the Australian-based fuel cell vehicle manufacturer at Port Kembla NSW with the Warrego ute, Snowy SUV and Darling HGV products. Coregas operates Australia's biggest industrial hydrogen supply with the Sydney Lane Cove production site and the Yennora liquid hydrogen plant. Air Liquide Australia runs industrial hydrogen scope at Sydney and Perth. BOC Australia, part of the Linde group, operates Hobart, Sydney and Perth industrial gas scope. Toyota Mirai and Hyundai Nexo are the FCEV passenger vehicle off-take customers with national HRS network access.

On the ammonia side Yara Pilbara runs the Burrup Peninsula WA ammonia plant, the YURI Project green hydrogen pilot with Engie and Mitsui, and the broader Pilbara ammonia export terminal. Hunter Valley Hydrogen Hub HVHH delivers Orica's ammonia decarbonisation pathway. Stanwell's CQ-H2 Aldoga site delivers green ammonia for Hyundai. Origin and AGL hold green ammonia and methanol scope across the Hunter Valley and Loy Yang sites respectively. On the green methanol and sustainable aviation fuel SAF side ABB Australia delivers SAF and renewable diesel HDRD scope, AGL Loy Yang holds green methanol scope, KBR Kellogg Brown and Root holds SAF process licensor scope, and Honeywell UOP holds the SAF technology licensor scope. Electrolyser OEM equipment is supplied by NEL Hydrogen out of Norway with alkaline and PEM stacks, ITM Power UK with PEM stacks, Cummins HyLYZER PEM, Plug Power PEM, Sunfire SOEC solid oxide, Siemens Silyzer PEM, Hydrogenics now Cummins-owned, McPhy Energy alkaline and Thyssenkrupp alkaline.

The hub portfolio under the Australian Clean Hydrogen Industrial Hubs Program and the National Hydrogen Strategy 2024 update is geographically distributed across Bell Bay TAS, Gladstone QLD, Port Kembla NSW, Hunter Valley NSW, Pilbara WA, Kwinana WA, Port Bonython SA, Port Augusta SA, Whyalla SA, Port Hedland WA, Wagga Wagga NSW and Eyre Peninsula SA. Each hub combines electrolyser production, downstream ammonia or methanol synthesis or LH2 liquefaction, port infrastructure or rail loading, and a refuelling station for the local heavy-vehicle and passenger fleet. The HVAC duct scope per hub runs to 8000 to 25000 square metres of formed sheet across galvanised, stainless and aluminised grades, with the dominant 316L stainless content driven by the AS/NZS 60079 Class I Zone 0/1/2 and ammonia-compatibility envelope.

3. The standards stack — AS/NZS 60079 Class I Zone 0/1/2 H2 hazardous area, NFPA 2, ISO 22734 and the rest

A hydrogen production, electrolyser, HRS or green ammonia plant in Australia sits at the intersection of the National Construction Code, Standards Australia, IEC, ISO, NFPA, ATEX and the National Hydrogen Strategy delivery framework. For HVAC ductwork the load-bearing standards are the ones below.

3.1 AS 1668.2 Mechanical Ventilation of Buildings

AS 1668.2 sets minimum outdoor air rates, smoke spill and contaminant dilution requirements for industrial buildings including electrolyser halls, ammonia synthesis loops, methanol distillation and refuelling station compressor packages. The standard interacts with AS/NZS 1715 for respiratory protection selection and AS/NZS 60079 for hazardous area classification through the dilution ventilation rate. For unmanned compounds the rate is sized by equipment heat rejection and credible leak dispersion, not occupant rate. The base reference for any duct sizing calculation on Australian hydrogen scope is AS 1668.2 with AS/NZS 1715 overlay.

3.2 AS 4254 Ductwork for Air-Handling Systems

AS 4254 Part 1 low-pressure and Part 2 medium and high pressure are the construction standards every metre of SBKJ-formed duct must satisfy. Leakage classes A through D, gauge tables and reinforcement spacing, hanger and support arrangement, joint and sealant class — every detail flows from AS 4254 onto the fabrication drawings. For hazardous-area duct in Zone 1 service the target is leakage Class A which is 0.5 litres per second per square metre of duct surface at 1000 Pascals operating pressure. SBKJ supplies the leakage certificate at handover as part of the Hydrogen Headstart audit pack.

3.3 AS 1530.4 Fire-Resistance Tests for Elements of Construction

AS 1530.4 governs fire-rated duct penetrations between fire compartments. On hydrogen plant ductwork the standard applies at every wall and floor crossing of the gas room, the electrolyser cell hall, the compressor package, the ammonia loop building, the methanol distillation column enclosure and the laboratory. Typical fire-resistance level is -/120/120 for the compartmentation around any high-inventory hydrogen space, with SBSF-1525 stitchwelded 316L fire-rated 250 degrees Celsius for 2 hour duct in the cross-compartment runs.

3.4 AS/NZS 60079 Explosive Atmospheres — Class I Zone 0/1/2 for Hydrogen IIC

The AS/NZS 60079 series adopts IEC 60079 verbatim for explosive atmospheres and is the dominant standard on every hydrogen plant. AS/NZS 60079.10.1 covers area classification for gases — the zone allocation drawing. AS/NZS 60079.14 covers electrical installation in hazardous areas. AS/NZS 60079.17 covers periodic inspection. AS/NZS 60079.19 covers repair. Gas group is IIC for hydrogen because hydrogen and acetylene have the lowest minimum ignition current ratio MICR of all flammable gases. Temperature class is T1 because hydrogen autoignition is 500 degrees Celsius with a surface temperature limit of 450 degrees Celsius. Zone allocation runs Zone 0 inside the cell stack and gas-tight enclosure, Zone 1 within 1 to 3 metres of stack manifolds and gas-liquid separators, and Zone 2 across the general electrolyser hall envelope. Every active electrical device installed inside Zone 1 or Zone 2 must carry IECEx or ATEX 2014/34/EU certification with equipment protection level Gb for Zone 1 and Gc for Zone 2, gas group IIC, temperature class T1, and the certificate copies are filed in the plant hazardous area register.

3.5 AS 1940 Storage and Handling of Flammable and Combustible Liquids

AS 1940 covers methanol storage, liquid ammonia storage including the refrigerated tank at minus 33 degrees Celsius, and liquid hydrogen LH2 storage at minus 253 degrees Celsius. The standard sets bund and containment requirements, separation distances and the ventilation rate for any enclosed handling area. On methanol-handling buildings the ventilation rate is 6 to 12 air changes per hour with vapour detection at 200 ppm WES per Safe Work Australia.

3.6 AS 4332 Specialty Gas, AS 2030 Gas Cylinders and AS 4041 Pressure Piping

AS 4332 covers specialty gas storage and handling — industrial hydrogen, oxygen, nitrogen, argon and helium cylinders and bundles on the laboratory, electrolyser commissioning and calibration scope. AS 2030 covers gas cylinders and the pressure vessel requirements including the Type IV composite carbon fibre wound 200 to 1000 bar hydrogen tanks used on tube trailers and refuelling station storage banks. AS 4041 pressure piping governs the vent stack and process header piping with material selection in stainless 316L, duplex 2205, super duplex 2507 and Inconel 625 depending on temperature and corrosion environment. AS 4037 covers pressure vessels referenced alongside ASME Boiler and Pressure Vessel Code, API and EN for the high-pressure hydrogen storage. AS 3873 covers the safe use of volatile hazardous substances and applies to the methanol and acetone handling scope.

3.7 AS 4564 and AS 5601 Gas Installation

AS 4564 covers LPG installation and AS 5601 covers gas installation in general — both referenced for the gas regulation, metering and pressure control scope on hydrogen tube trailer loading and the refuelling station inlet manifold. Cross-reference with AS/NZS 1596 LPG storage where the hydrogen storage geometry mirrors LPG cylinder bundle arrangement.

3.8 AS 1716 and AS 1715 Respiratory Protection

AS 1716 RPE classification and AS 1715 RPE selection set the worker respiratory protection envelope on any hydrogen, ammonia, methanol or caustic mist exposure. The HVAC ductwork design intent is to keep airborne concentrations below the relevant Safe Work Australia WES without RPE dependency for routine operations, with RPE reserved for upset or maintenance entry.

3.9 NFPA 2 Hydrogen Technologies Code — the Dominant Project Reference

NFPA 2 Hydrogen Technologies Code is the dominant international reference adopted as project specification on Australian hydrogen scope financed under US insurer, ARENA Hydrogen Headstart and CEFC criteria. The code covers gaseous hydrogen storage, liquid hydrogen storage, generation, transportation, dispensing and use. NFPA 2 Chapter 6 vent stack design rules drive the 7.6 metre above-roof separation, 6 metre air-intake clearance and flame arrester tip requirement. NFPA 2 Chapter 7 covers indoor handling and the ventilation rate sizing. NFPA 853 covers hydrogen combined heat and power CHP. NFPA 855 covers stationary energy storage systems including Li-ion BESS adjacent to electrolyser plant. NFPA 70 NEC covers the electrical installation and NFPA 13 covers sprinkler protection.

3.10 ATEX Directive 2014/34/EU and IEC 60079

ATEX Equipment Directive 2014/34/EU governs the certification of equipment for use in explosive atmospheres in the European supply chain — every electrolyser stack, compressor package, dispenser and ionic liquid skid imported from NEL, ITM, Cummins, Plug Power, Sunfire, Siemens, Hydrogenics, McPhy or Thyssenkrupp carries an ATEX certificate. IEC 60079 is the international parallel — AS/NZS 60079 adopts IEC 60079 verbatim. Zone 0/1/2 covers gases and vapours, Zone 20/21/22 covers dusts. The certificate dossier for every component installed in any zone is part of the plant hazardous area register.

3.11 IEC 62282 Fuel Cell and ISO 22734 Electrolyser

IEC 62282 covers fuel cell technology — stationary and mobile fuel cells including Toyota Mirai, Hyundai Nexo, H2X products, Ballard, Plug Power, Cummins Power Generation, Bloom Energy SOFC, Mitsubishi and Toshiba units. ISO 22734 covers industrial alkaline and PEM electrolyser packages and sets the type-test, factory acceptance test FAT and site acceptance test SAT requirements for a complete electrolyser system. The standard requires hazardous area classification, hydrogen detection performance to ISO 26142, mechanical ventilation rate justification, emergency shutdown logic and gas-tight enclosure integrity.

3.12 ISO 14687 Hydrogen Fuel Quality — 99.999 Percent for FCEV

ISO 14687-2 fuel quality grade D for fuel cell vehicles sets 99.999 percent hydrogen purity with specific maximum contaminant limits — particulate matter below 1 milligram per kilogram, total sulphur below 0.004 ppm, ammonia below 0.1 ppm, formaldehyde below 0.01 ppm, formic acid below 0.2 ppm, total hydrocarbons below 2 ppm, carbon monoxide below 0.2 ppm. The platinum membrane electrode assembly inside a PEM fuel cell is irreversibly poisoned by even ppb-level sulphur, ammonia and carbon monoxide. The HVAC implication is the dedicated fuel quality laboratory housing GC, MS and trace contaminant detectors at controlled environment.

3.13 ISO 19880 Hydrogen Fuelling Station and ISO 17268 Nozzle

ISO 19880-1 covers gaseous hydrogen fuelling station design and is the global reference adopted in Australia by the Australian Hydrogen Council AHC and Hydrogen Mobility Australia HMA. ISO 17268 covers the dispenser nozzle for 350 bar bus and truck and 700 bar passenger car connections. SAE J2601 fuelling protocol defines the precooling, pressure ramp and target state-of-charge for a 3 to 5 minute fill of a 5 kilogram passenger vehicle tank. The HVAC envelope for the HRS dispenser canopy is natural ventilation through 50 percent open perimeter, with the enclosed compressor package on mechanical displacement ventilation at 12 to 20 ACH.

3.14 ISO 26142 Hydrogen Detection Apparatus

ISO 26142 sets performance requirements for hydrogen detection apparatus — response time below 30 seconds at 1 percent hydrogen, accuracy plus or minus 5 percent of full scale, immunity to common cross-interferents including methane, carbon monoxide and humidity. Detectors are IECEx certified for gas group IIC, mounted at ceiling level on a maximum 10 metre by 10 metre grid with additional detectors at high-risk release points.

3.15 AS/NZS 1554.1, 1554.6 and 1554.7 Welding

The AS/NZS 1554 series covers welding of stainless steel, pressure piping and structural steel. AS/NZS 1554.6 covers welding of stainless steel and is the load-bearing standard for the longitudinal seam welds and the field joints on 316L hydrogen and ammonia duct. Continuously welded TIG GTAW seams are mandatory in Zone 1 service — Pittsburgh seams are not permitted under AS/NZS 60079.14 in Zone 1.

3.16 Safe Work Australia Workplace Exposure Standards

The Safe Work Australia WES register sets the airborne concentration limits the HVAC ductwork must keep below in normal operation. The hydrogen-and-downstream WES schedule is dominated by hydrogen 4 percent LEL action level with the killer 0.017 millijoule minimum ignition energy, carbon monoxide 30 ppm STEL on legacy SMR steam methane reformer and ATR auto thermal reformer scope, carbon dioxide 5000 ppm on blue hydrogen with carbon capture and storage CCS, methane 1.25 percent LEL on blue hydrogen and SMR ATR scope, ammonia NH3 25 ppm 8-hour TWA and 35 ppm STEL on green ammonia Haber-Bosch, methanol CH3OH 200 ppm on methanol synthesis with skin absorption, blindness and death risk on dermal exposure, formic acid HCOOH 5 ppm on methanol decomposition and contamination, formaldehyde HCHO 1 ppm STEL on methanol oxidation and partial cracking, potassium hydroxide KOH and sodium hydroxide NaOH 2 milligrams per cubic metre ceiling on alkaline electrolyser caustic mist with strong alkaline burn hazard, hydrogen fluoride HF 1.8 ppm STEL on PEM Nafion membrane degradation, oxygen O2 23.5 percent maximum on the electrolyser anode and air separation unit ASU with fire and explosion risk if oxygen-enriched, nitrogen N2 19.5 to 23.5 percent O2 envelope with asphyxiation risk in low-O2 conditions on liquid LN2, LH2, LNG and inert atmosphere scope, argon Ar and helium He as asphyxiants, hydrogen sulphide H2S 10 ppm TWA and 15 ppm STEL on legacy SMR sour gas and ATR scope, mercury Hg 0.025 milligrams per cubic metre on legacy chlor-alkali phase-out scope, oxides of nitrogen NOx 5 ppm STEL on combustion and chlorine Cl2 0.5 ppm STEL on cooling tower and legacy chlor-alkali. The HVAC dilution rate is sized against the most-stringent applicable WES across the inventory.

3.17 ARENA, CEFC, AEMO, AER, CER, NHS and the Australian Hydrogen Council

The Australian Renewable Energy Agency ARENA administers Hydrogen Headstart and the Australian Clean Hydrogen Industrial Hubs Program. The Clean Energy Finance Corporation CEFC provides the financing arm. The Australian Energy Market Operator AEMO, the Australian Energy Regulator AER and the Clean Energy Regulator CER set the broader market envelope. The National Hydrogen Strategy NHS 2019 and the 2024 update with the 2030 production cost target of less than 2 USD per kilogram and the H2HEADSTART program define the federal policy backbone. The Australian Hydrogen Council AHC is the peak industry body and Hydrogen Mobility Australia HMA covers the FCEV side. Energy Networks Australia ENA, the CSIRO Hydrogen Research Network, Future Fuels CRC and the HyResource Database round out the support framework. The HVAC fabrication and machinery supply chain serving this build operates within that regulatory envelope.

4. The green hydrogen electrolyser hall — alkaline KOH, PEM Nafion and SOEC solid oxide

The green hydrogen electrolyser is the production engine of the Australian hydrogen build. Three competing technologies dominate the FEED and EPC pipeline. Alkaline AEL is the mature workhorse using 25 to 30 percent potassium hydroxide KOH or sodium hydroxide NaOH electrolyte at 70 to 90 degrees Celsius across a porous diaphragm separating the cathode hydrogen evolution from the anode oxygen evolution. Suppliers include NEL Hydrogen out of Norway, McPhy Energy and Thyssenkrupp. Polymer electrolyte membrane PEM uses a Nafion proton exchange membrane at 60 to 90 degrees Celsius with deionised water rather than caustic, with suppliers including ITM Power UK, Cummins HyLYZER, Plug Power, Siemens Silyzer and Hydrogenics now Cummins-owned. Solid oxide electrolyser cell SOEC operates at 700 to 900 degrees Celsius with steam feed, principally Sunfire out of Germany.

The HVAC scope responds in three layers regardless of technology. Layer one is dilution ventilation across the cell stack hall to keep any diffuse leak below 25 percent of LEL — typical 8 to 15 air changes per hour with 316L stainless ductwork and IECEx Ex d IIC equipment. For a 100 MW electrolyser hall covering 5000 to 7000 square metres at 12 metre ceiling height that is 60000 to 150000 cubic metres per hour of supply and an equal or slightly higher volume of exhaust to maintain a small negative pressure inside the hall relative to surrounding clean areas. Exhaust grilles sit within 300 millimetres of the highest ceiling point because hydrogen relative density is 0.0695 and rises rapidly. SBKJ ductwork sizes the supply collection at 8 to 10 metres per second face velocity and the high-level exhaust trunks at 12 to 15 metres per second to keep duct cross-section compact while staying inside a 200 to 300 Pascal system pressure budget.

Layer two is local exhaust ventilation on the KOH dosing and circulation skids in the alkaline plant to capture caustic mist below the 2 milligrams per cubic metre ceiling exposure limit per Safe Work Australia WES. LEV capture face velocity is 0.5 metres per second per AS 1668.2 LEV principles, with 316L stainless duct routed through a chevron-style caustic mist eliminator before atmospheric discharge. Galvanised duct pits within weeks under caustic so the specification is hard 316L throughout. On PEM electrolyser plants the equivalent risk is sulphuric acid mist from deconditioning, Safe Work Australia WES 1 milligram per cubic metre, with FRP vinyl ester duct on the acid mist run.

Layer three is dedicated stack-vent piping from each gas-liquid separator routed to atmospheric vent stacks 7 to 15 metres above roof per NFPA 2 Chapter 6, never combined with HVAC return air. Vent stack discharge piping is hard-pipe 316L per AS 4041 with full-penetration TIG welds verified by NDT, fitted with a flame arrester at the stack tip or a continuous nitrogen purge to prevent flashback. The diameter is sized per API 521 for the credible blowdown flow, typically 100 to 500 kilograms per hour of hydrogen on a 100 MW electrolyser stack runaway scenario.

SBKJ machine deployment on the cell hall scope runs SBAL-V at 316L for the dilution supply and return ductwork, SBAL-III for the larger gauge scope, SBSF-1525 stitchwelder for the seam closure, SB-ZF1500 for the stack manifold collectors and plenums, SBFB-1500 spiral for the vent stack risers, SBPC1500 plasma for the access penetrations and SBLR-600 manual welding for the field joints. The fabrication target is AS 4254 leakage Class A on every duct in the zoned envelope, with leakage certificate witness-tested by a NATA-accredited inspector at handover.

5. H2 compression and storage — ionic liquid, piston and diaphragm to 1000 bar

Downstream of the electrolyser the hydrogen stream is compressed from the cell-stack outlet pressure typically 30 bar through multiple stages to the storage and dispensing pressure. The compression scope drives a substantial HVAC envelope because hydrogen compression generates significant waste heat and the compressor package itself is the largest single source of credible Zone 1 hydrogen leak in the plant.

Compressor technology choice runs across four families. Ionic liquid compression from Linde and Hofer uses a non-flammable ionic liquid as the piston with no metal-on-metal contact in the compression cylinder — preferred at the 350 to 1000 bar discharge end of the chain for refuelling station storage. Reciprocating piston compression from Burckhardt, RIX and Howden handles the lower-pressure stages with diaphragm sealing on the gas-end. Diaphragm compression from Howden and PDC handles intermediate stages with full hermetic gas containment. Vapour seal compression with multi-stage heat exchange and chiller integration covers the high-flow electrolyser-outlet duty.

Compressor halls handle hydrogen at 30 to 1000 bar with significant waste heat — a 20 MW hydrogen compressor station rejects 4 to 5 MW of heat to the surrounding building. Specify displacement ventilation strategy with low-level supply at 4 to 6 metres per second through floor grilles, high-level exhaust through ceiling grilles, 15 to 20 ACH normal rising to 25 to 30 ACH on first-stage hydrogen alarm. Building cooling load is 200 to 500 Watts per square metre of floor area. Slight negative pressure relative to control room contains any leak. ATEX-rated compressors per the package vendor specification, with hydrogen detection on intake and exhaust paths interlocked to compressor package emergency shutdown.

SBKJ ductwork on the compressor hall scope is SBAL-V at 316L for the rectangular dilution supply and return, SBFB-1500 round 316L for the displacement floor-grille supply trunks and the high-level exhaust risers, SB-ZF1500 stainless plenum for the compressor cell-by-cell extract collector, and SBPC1500 plasma for the access panels. The compressor hall HVAC is interlocked with the gas detection on a 10 metre by 10 metre ceiling grid, first alarm at 25 percent LEL triggering ventilation boost and second alarm at 50 percent LEL triggering compressor shutdown, blowdown to the vent stack and full plant alarm.

6. The H2 refuelling station — 350 bar heavy vehicle and 700 bar passenger car

The hydrogen refuelling station HRS scope sits at the customer interface of the hydrogen value chain. ATCO Jandakot WA, Fortescue Williamtown NSW, Coregas at Sydney, Stockmans Way Macquarie Park NSW operated by Engie, and the announced expansion to Wagga Wagga NSW, Eyre Peninsula SA and Bell Bay TAS form the current Australian HRS portfolio. The 700 bar passenger car dispenser serves Toyota Mirai, Hyundai Nexo and the H2X Global Warrego, Snowy and Darling products manufactured at Port Kembla. The 350 bar dispenser serves Hyzon heavy vehicles and the broader bus and truck fleet.

ISO 19880-1 covers the global station design with the dispenser canopy classified Zone 1 within 1 metre of the nozzle and breakaway connection during refuelling, Zone 2 within 3 metres in all directions during refuelling, and unclassified at other times. The vehicle parking position is Zone 2 during refuelling and unclassified at other times. The canopy itself is open-louvred on at least 50 percent of its perimeter so natural ventilation handles the small credible leak envelope at the nozzle. SBKJ deploys SBFB-1500 round 316L for the canopy structural support penetrations and the optional supplementary mechanical ventilation drops where the perimeter open area falls short.

The enclosed compressor package handling ionic, piston or diaphragm compression up to 1000 bar runs mechanical displacement ventilation at 12 to 20 air changes per hour with low-level supply and high-level exhaust, 316L stainless ductwork, ISO 26142 detection at 10 and 25 percent LEL interlocked to compressor emergency shutdown and refuelling cut-off. Type IV composite carbon fibre wound tanks at 350 or 700 bar working pressure store the hydrogen between compression and dispensing. The pre-cool chiller package takes the dispensed hydrogen to minus 40 degrees Celsius per SAE J2601 protocol for 3 to 5 minute fuelling of a 5 kilogram passenger vehicle tank with conventional refrigeration HVAC outside the hazardous envelope.

The dispenser itself is ATEX certified with the ISO 17268 nozzle, the SAE J2601 communication protocol for CHAdeMO H2 and IRDA infrared, an N2 purge between fills, leak detection at the breakaway, flame detection with thermal imaging FLIR camera coverage and a remote shutoff. Canopy ventilation extracts at high level through a 316L stainless plenum fabricated on the SB-ZF1500, with discharge to atmosphere through a vent riser routed up and away from any structure within 6 metres horizontal.

The HRS site also includes a small control booth or fee-collection kiosk that is conventional commercial HVAC outside the hazardous envelope, and the tube trailer or pipeline delivery interface which is Zone 1 around the connection during transfer with portable forced-ventilation fans rather than fixed ducted ventilation. The fabrication scope per HRS site runs 200 to 800 square metres of formed 316L sheet plus 50 to 150 square metres of galvanised on the unclassified portions.

7. Liquid hydrogen LH2 at minus 253 degrees Celsius and the Coregas Yennora liquefier

Liquid hydrogen production cools gaseous hydrogen through a multi-stage refrigeration cycle to minus 253 degrees Celsius, just above the 20 Kelvin boiling point. The principal Australian operator is Coregas at the Yennora NSW liquid hydrogen plant which is the biggest H2 supplier on the east coast. Linde, Air Liquide and Praxair operate parallel global scope. The Stanwell CQ-H2 Aldoga site includes a liquefier for Iwatani export to Japan.

The cycle pre-cools hydrogen with liquid nitrogen at minus 196 degrees Celsius from a co-located air separation unit ASU, then runs a helium Brayton cycle to drop further temperature, then a Joule-Thomson expansion to reach minus 253 degrees Celsius. An ortho-para conversion catalyst converts the para-hydrogen at production temperature to the lower-energy isomer at storage temperature, releasing heat that must be removed in a dedicated heat exchanger. The liquid product is stored in vacuum-insulated double-wall dewar vessels with minimum boil-off loss.

Three HVAC consequences dominate the cold box room. Cold surface oxygen condensation occurs on any surface below minus 183 degrees Celsius which is the boiling point of oxygen at atmospheric pressure — any insulation fault or vacuum jacket breach can produce a localised oxygen-enriched zone with combustion risk if any organic material is present. The cold box room HVAC runs displacement ventilation with low-level supply at 4 to 6 metres per second face velocity and high-level exhaust, plus oxygen detection at floor level with first alarm at 23.5 percent O2 and lower limit at 19.5 percent O2 per Safe Work Australia WES.

Released LH2 vapour is initially denser than ambient air and sinks into low points before warming above approximately 22 degrees Celsius at which it becomes buoyant. So the displacement ventilation strategy with low-level supply and high-level exhaust serves the dual purpose of removing cold vapour from low points and rising vapour from high points. Boiling liquid expanding vapour explosion BLEVE risk from fire impingement on the storage tank drives 30 to 50 metre separation from any occupied building per project-specific QRA. Fresh air intakes for adjacent buildings sit on the side facing away from the LH2 tank with minimum 20 metre horizontal and 10 metre vertical separation.

SBKJ ductwork on the cold box scope is 316L stainless throughout, with cryogenic-rated insulation on any duct exposed to vapour-temperature transients. The fabrication chain is SBAL-V at 316L for the bulk rectangular runs, SBFB-1500 round 316L for the floor-level supply trunks and high-level exhaust risers, SB-ZF1500 for the manifold and plenum scope, SBTF-1602 or SBTF-2020 for the larger diameter spiral exhaust trunks, SBPC1500 plasma for the penetrations and SBLR-600 manual welding for the field joints. PRV discharge piping from the storage tank is hard-pipe 316L per AS 4041, never routed through HVAC ductwork.

8. Hydrogen compressed gas tube trailer and pipeline distribution

Distribution scope downstream of the production plant runs across road tube trailers and the small but growing pipeline network. Coregas, Air Liquide, BOC and Linde all operate tube trailer fleets at 200 to 350 bar working pressure carrying 250 to 1000 kilograms of hydrogen per trailer. Trailer loading bays sit at the production plant and offloading bays sit at the customer site — both Zone 1 around the connection during transfer per AS/NZS 60079.

The loading and offloading bay HVAC is canopy-style with natural ventilation through 50 percent open perimeter, or partly enclosed with mechanical ventilation at 10 to 15 ACH and 316L stainless duct on any extract path. ISO 26142 hydrogen detection at the canopy peak interlocked to transfer cut-off at 10 and 25 percent LEL is mandatory. Tube trailer regulation, metering and pressure control follow AS 4564 and AS 5601 gas installation rules with the cross-reference to AS/NZS 1596 LPG storage where the cylinder bundle geometry mirrors LPG bundle arrangement.

Pipeline distribution is rare in Australia at 2026 but growing. Yara Pilbara has a short pipeline from electrolyser to ammonia synthesis loop on the Burrup Peninsula WA. The Hunter Valley Hydrogen Hub planning includes a pipeline link from the electrolyser site to the ammonia and methanol downstream off-take. Future hub-network pipelines under the Australian Clean Hydrogen Industrial Hubs Program will extend to the port export terminals. Pipeline material is DN50 to DN300 stainless 316L, duplex 2205, super duplex 2507 or Inconel 625 depending on temperature and partial pressure, welded longitudinal seam with post-weld heat treat PWHT and full NDT under AS 4041 pressure piping. The pipeline itself is process scope outside HVAC ductwork but the pipeline metering station and the cathodic protection rectifier kiosk are HVAC scope.

SBKJ ductwork on the trailer and pipeline scope is SBFB-1500 round 316L for the loading bay canopy extract risers, SBAL-V at 316L for the metering station enclosure dilution ventilation, SB-ZF1500 for the rectifier kiosk plenum and SBPC1500 plasma for the penetrations.

9. Green ammonia Haber-Bosch — Yara Pilbara Burrup Peninsula WA and the YURI Project

Green ammonia is the dominant export carrier for Australian hydrogen scope. The Haber-Bosch synthesis loop combines green hydrogen from the electrolyser with nitrogen from a co-located air separation unit ASU, passing the syngas at 200 to 300 bar and 400 to 500 degrees Celsius over a promoted iron or ruthenium catalyst to produce ammonia NH3. Yara Pilbara at Burrup Peninsula WA is the principal Australian operator with the YURI Project pilot in partnership with Engie and Mitsui. The Hunter Valley Hydrogen Hub HVHH partnership between Origin and Orica delivers the Hunter ammonia decarbonisation pathway. Stanwell's Central Queensland Hydrogen Project CQ-H2 Aldoga delivers green ammonia for Hyundai. Process licensors include ICI Casale, Haldor Topsoe, Ammonia Casale, KBR Kellogg Brown and Root, Topsoe SynCOR and Mitsui.

The synthesis loop is dual-zoned per AS/NZS 60079. The hydrogen-rich syngas side is Class I Zone 2 hydrogen IIC with continuous mechanical ventilation at 10 to 15 air changes per hour and 316L stainless ductwork. The ammonia side is a separate toxic-gas zone with electrochemical NH3 detectors at breathing height on an 8 to 10 metre grid, first alarm at 25 ppm 8-hour TWA per Safe Work Australia WES and second alarm at 35 ppm STEL interlocked to converter trip and depressurisation to enclosed flare or scrubber stack. Refrigerated ammonia storage at minus 33 degrees Celsius is Class I Zone 2 around tank breathers and pump seals, with NH3-scrubber stacks discharging through caustic neutralisation before atmospheric vent.

Material specification is 316L stainless ductwork throughout with absolute exclusion of copper, brass and bronze. Anhydrous NH3 attacks copper-bearing alloys rapidly, forming soluble copper-ammine complexes that destroy copper components within hours of exposure. Specify aluminium-wound or copper-free coated motors, all-aluminium or stainless-tube refrigeration coils, aluminium-bronze-free dampers, and zero brass or zinc plating on flexible duct connector wires. The cost uplift on the affected equipment is 15 to 25 percent but is non-negotiable.

Loading and unloading manifolds on rail and road are Zone 1 around the connection during transfer, with NH3 scrubber stacks discharging through caustic neutralisation before atmospheric vent. Loading arm control booths are positive-pressure refuges with filtered fresh air supply and NH3 detection on the intake.

SBKJ ductwork on the green ammonia scope is SBAL-V at 316L for the dilution supply and return, SBSF-1525 stitchwelder for the seam closure under AS/NZS 60079.14 Zone 1 requirements, SB-ZF1500 stainless plenum for the synthesis loop manifold and the NH3 scrubber inlet plenum, SBFB-1500 spiral 316L for the scrubber stack riser, SBTF-1602 or SBTF-2020 for the larger diameter scrubber ducting up to 2020 millimetres, SBPC1500 plasma for the penetrations and SBLR-600 manual welding for the field joints. The fabrication target is AS 4254 leakage Class A throughout with witness test by NATA-accredited inspector at handover and a Safe Work Australia WES baseline survey for NH3 before first synthesis gas.

10. Blue hydrogen, SMR steam methane reformer and ATR auto thermal reformer

Blue hydrogen via steam methane reforming SMR and auto thermal reforming ATR is the legacy Australian production scope at Yara Pilbara WA, Incitec Pivot phosphate plants and Orica ammonia operations. The process combines natural gas with steam at 700 to 1000 degrees Celsius over a nickel catalyst to produce syngas containing hydrogen, carbon monoxide and carbon dioxide, then runs a shift converter to convert CO with additional steam to more H2 and CO2, then a pressure swing adsorption PSA unit to separate the hydrogen at 99.9 percent purity. ATR uses partial oxidation with an oxygen stream from a co-located air separation unit instead of indirect steam reforming. With carbon capture and storage CCS on the CO2 stream the product is blue hydrogen.

The HVAC scope on legacy SMR and ATR plants overlaps with green hydrogen on the downstream side but includes additional WES-driven dilution rate on carbon monoxide CO at 30 ppm STEL, hydrogen sulphide H2S at 10 ppm TWA and 15 ppm STEL where sour gas feed contributes, methane CH4 at 1.25 percent LEL on natural gas leak, and carbon dioxide CO2 at 5000 ppm on CCS scope. Material specification follows green hydrogen with 316L stainless throughout the high-pressure side, with carbon steel acceptable on the cooled-and-dried low-pressure portions.

11. Green methanol synthesis and sustainable aviation fuel SAF

Green methanol via CO2 hydrogenation and sustainable aviation fuel SAF via the Fischer-Tropsch or alcohol-to-jet pathway are emerging Australian export carriers. AGL Loy Yang holds green methanol scope on the brownfield coal site. Stanwell and Origin hold SAF scope on the Hunter Valley and Aldoga sites. ABB Australia ABL delivers SAF and renewable diesel HDRD scope. KBR Kellogg Brown and Root is the SAF process licensor. Honeywell UOP holds the alternative SAF technology licensor scope.

Methanol synthesis combines CO and H2 over a copper-zinc-aluminium catalyst at 250 degrees Celsius and 50 to 100 bar to produce methanol CH3OH. The synthesis loop is followed by separation, distillation and purification to fuel-grade or chemical-grade methanol. Methanol storage follows AS 1940 flammable liquid rules with bund containment, methanol vapour detection at the Safe Work Australia WES of 200 ppm 8-hour TWA, dermal absorption hazard with the methanol blindness and death risk on skin exposure, and 6 to 12 ACH ventilation in any enclosed handling area. Distillation column enclosures are Class I Zone 2 around tray manifolds and pump seals.

The HVAC ductwork material on the methanol side is 316L stainless throughout the synthesis loop and distillation enclosure, with carbon steel acceptable on the unclassified cooled side. SBKJ deploys SBAL-V at 316L for the dilution supply and return, SBFB-1500 spiral 316L for the column vent riser, SB-ZF1500 stainless plenum for the column overhead vapour collector, SBTF-1500 or SBTF-1602 for the larger diameter vent ducting and SBPC1500 plasma for the penetrations.

Sustainable aviation fuel SAF synthesis on the alcohol-to-jet pathway runs ethanol or methanol through dehydration, oligomerisation and hydrogenation to produce jet-range hydrocarbons. The Fischer-Tropsch pathway runs syngas H2 plus CO over an iron or cobalt catalyst at 200 to 350 degrees Celsius and 20 to 30 bar to produce a hydrocarbon range from C5 to C30 which is then hydrocracked to the jet, diesel and naphtha cuts. SAF storage follows AS 1940 with conventional jet fuel handling rules. The HVAC ductwork specification mirrors petrochemical aviation fuel handling with carbon steel on the unclassified side, 304 or 316L stainless on the distillation and treatment side, and ATEX-rated extract on any flammable vapour enclosure.

12. Electrolyser OEM assembly and test plant

The electrolyser OEM assembly and test plant scope is an emerging Australian opportunity as the Hydrogen Headstart and Australian Clean Hydrogen Industrial Hubs Program drives local manufacturing content. NEL Hydrogen, ITM Power, Cummins HyLYZER, Plug Power, Sunfire SOEC, Siemens Silyzer, Hydrogenics, McPhy Energy and Thyssenkrupp all hold global manufacturing scope with potential Australian assembly partnerships. The Hysata stack out of Wollongong NSW represents the most advanced Australian-origin electrolyser technology with capillary-fed alkaline architecture.

The assembly plant HVAC is conventional advanced manufacturing — temperature and humidity controlled cell assembly bay at 22 plus or minus 2 degrees Celsius and 45 plus or minus 10 percent relative humidity, controlled-particulate environment per ISO 14644 for the membrane handling and the platinum catalyst deposition, and a separate test cell bay where assembled stacks undergo factory acceptance test FAT with hydrogen and oxygen evolution. The test cell bay is Class I Zone 0/1/2 throughout because hydrogen evolution at FAT scale presents the same hazard as production-scale operation. SBKJ deploys SBAL-V at 316L for the test cell dilution supply and return, SBFB-1500 spiral 316L for the vent stack riser, SB-ZF1500 stainless plenum for the cell-stack vent manifold, SBPC1500 plasma for the penetrations and SBLR-600 manual welding for the field joints.

13. Fuel cell FCEV and stationary fuel cell HVAC

The fuel cell FCEV side of the Australian hydrogen value chain runs across Toyota Mirai and Hyundai Nexo passenger imports, the H2X Global Port Kembla NSW manufacturing scope for the Warrego ute, Snowy SUV and Darling HGV products, the Hyzon Motors heavy-vehicle demonstration scope, and the stationary fuel cell scope from Ballard, Plug Power, Cummins Power Generation, Bloom Energy SOFC, Mitsubishi and Toshiba.

The H2X Port Kembla manufacturing plant HVAC scope is conventional advanced vehicle manufacturing on the body, paint and assembly side, with a dedicated fuel cell stack assembly bay at controlled environment per ISO 14644 Class 8 or better, and a final vehicle test cell where the fuel cell vehicle is charged with hydrogen for end-of-line test. The test cell is Class I Zone 1 throughout with mechanical displacement ventilation at 15 to 25 ACH, 316L stainless ductwork, ISO 26142 detection and ATEX-rated motors and dampers.

Stationary fuel cell installations for backup power, distributed generation or grid-services typically sit in dedicated enclosures supplied factory-integrated by the OEM with their own ventilation provisions. The site-level HVAC scope is limited to the enclosure intake and exhaust ventilation ducts and any safety vent riser. SBKJ deploys SBFB-1500 spiral 316L for the safety vent riser and SBAL-V at 316L for any supplementary dilution ductwork.

14. Hydrogen test cell, commissioning and dyno

Hydrogen engine and turbine commissioning is an emerging scope. Cummins H2 ICE Internal Combustion Engine, MAN Hydrogen ICE and Wartsila Hydrogen engine programmes all require dedicated test cells with full hazardous area envelope. The test cell is a separately enclosed AS/NZS 60079 Zone 1 facility with continuous mechanical ventilation, ISO 26142 detection, thermal imaging FLIR camera coverage, and a remote shutoff at every credible leak point. The engine exhaust is hot water vapour at 95 to 105 degrees Celsius which is handled in a dedicated exhaust duct routed to an external silencer and condenser.

SBKJ ductwork on the test cell scope is SBAL-V at 316L for the cell dilution supply and return, SBFB-1500 spiral 316L for the engine exhaust riser routing to silencer and condenser, SB-ZF1500 stainless plenum for the exhaust collection manifold and SBPC1500 plasma for the cell wall penetrations. The fabrication target is AS 4254 leakage Class A throughout the cell envelope and on the exhaust riser, with witness test at handover.

15. Hydrogen hub control room, SCADA and DCS

The control room scope on a hydrogen hub is the mission-critical climate-controlled space housing the SCADA system, the distributed control system DCS, the electrolyser package vendor PLC, the ammonia synthesis loop SIS safety instrumented system, the hydrogen detection panel, the emergency shutdown logic and the operator workstations. The HVAC specification follows ASHRAE TC 9.9 Class A1 at 22 to 27 degrees Celsius with N+1 redundant CRAC units, ESD-safe finishes and a separate climate zone from the surrounding electrolyser hall, compressor package and ammonia loop building.

The control room is specified as a positive-pressure refuge at 50 to 100 Pa above the surrounding plant with separate filtered fresh air supply, hydrogen detection on the intake duct, and the outdoor intake located on the side facing away from any hydrogen vent stack with minimum 20 metre horizontal and 10 metre vertical separation. On detector trip the control room HVAC switches to recirculation mode and isolates from outside air until contamination clears. Egress doors are interlocked airlocks to maintain pressure during personnel movement.

SBKJ ductwork on the control room scope is conventional commercial — SBAL-V galvanised supply and return at low pressure with stainless return-air grilles to resist coil sweat, AS 4254 leakage Class C minimum and Class D preferred, fan plant N+1 with automatic transfer on fan failure detected at the BMS. SBFB-1500 spiral galvanised handles the long horizontal runs between the CRAC units and the distributed grille drops.

16. Emergency vent stack, flare and enclosed flare HVAC adjacency

The emergency vent stack, flare and enclosed flare scope is the safety end-of-line for any credible hydrogen, ammonia or methanol release. NFPA 2 Chapter 6 sets vent stack design rules for hydrogen — discharge upward and outward, terminate at least 7.6 metres above the roof of any enclosed building within 15 metres horizontal, maintain 6 metres separation from any air intake or door opening, and protect against flashback ignition with a flame arrester at the stack tip or a continuous nitrogen purge.

Stack diameter is sized per API 521 for the credible blowdown flow, typically 100 to 500 kilograms per hour of hydrogen on a 100 MW electrolyser stack runaway scenario. Stack piping is hard-pipe 316L stainless per AS 4041 with full-penetration TIG welds verified by NDT. Enclosed flare and thermal oxidiser RTO units handle the higher-inventory ammonia and methanol vent streams with combustion at 850 to 1100 degrees Celsius and a downstream cooling and scrubbing train.

The HVAC adjacency to the vent stack and flare is the air-intake separation envelope. Every HVAC fresh air intake on the plant must sit minimum 20 metres horizontal and 10 metres vertical from any vent stack outlet, and never on the prevailing-wind downstream side. The 316L stack riser is fabricated separately from the HVAC ductwork though often in the same shop. SBKJ supplies SBFB-1500 spiral 316L for the riser fabrication, SBPC1500 plasma for the access penetrations and SBLR-600 manual welding for the field joints.

17. Hydrogen storage cavern and underground salt cavern

Underground hydrogen storage is rare in Australia at 2026 but proposed at Port Bonython SA and Bell Bay TAS. The storage cavern is a mined rock cavern or solution-mined salt cavern accessed through a wellhead at surface, with hydrogen stored at 50 to 200 bar working pressure. The HVAC scope is limited to the wellhead control building, the metering station and the cavern overpressure relief vent stack — all conventional electrolyser-plant HVAC envelope as covered in Sections 4 through 16.

18. SBKJ machine selection — SBAL-V, SBAL-III, SBSF-1525, SB-ZF1500, SBFB-1500, SBPC1500, SBLR-600 and SBTF-1500/1602/2020

The SBKJ Group fabrication machinery base across Box Hill North VIC and the partner network covers every duct fabrication operation required on Australian hydrogen, electrolyser, HRS, green ammonia, methanol and hub scope.

18.1 SBAL-V Auto Duct Production Line

The SBAL-V auto duct production line in 316L stainless configuration is the workhorse for the cell hall dilution supply and return, the compressor package displacement ventilation, the ammonia synthesis loop dilution ductwork and the refuelling station compressor skid ventilation. The line accepts 316L coil 0.7 to 1.5 millimetres thick and produces TDF flanged rectangular duct from 200 to 1500 millimetres wide at 8 to 12 metres per minute on 1 millimetre 316L. The line integrates coil feeding, levelling, notching, seam forming, TDF flange forming and shear-to-length in a single pass, producing duct ready for the SBSF-1525 stitchwelder closure. Single-shift production on the SBAL-V in 316L delivers 6000 to 10000 square metres per week.

18.2 SBAL-III Third-Generation Auto Duct Line

The SBAL-III is the third-generation auto duct production line for the high-volume export scope and the heavier-gauge work above 1.2 millimetre 316L. The SBAL-III handles the larger duty cycles on the hub-scale projects where the duct scope reaches 15000 to 25000 square metres per project and the production schedule compresses to 12 to 16 weeks from contract.

18.3 SBSF-1525 Stitchwelder

The SBSF-1525 stitchwelder handles the longitudinal seam welding on 316L stainless rectangular duct. AS/NZS 60079.14 requires continuously welded seams in Zone 1 service — Pittsburgh seams are not permitted. The SBSF-1525 produces TIG GTAW seams to AS/NZS 1554.6 with full pickle-and-passivate post-weld treatment to restore the chromium oxide passive layer. The machine also handles the fire-rated 250 degrees Celsius for 2 hour duct seam closure for the cross-compartment runs at AS 1530.4 fire boundaries.

18.4 SB-ZF1500 Stainless Plenum and Manifold Press

The SB-ZF1500 is the dedicated 316L stainless plenum and manifold fabrication press for the cell stack manifold collectors, the gas-liquid separator vent plenums, the ammonia scrubber stack inlet plenum, the methanol distillation column overhead vapour collector and the high-pressure vent stack root. The machine produces stitchwelded stainless assemblies to the required sealing class with full corrosion resistance.

18.5 SBFB-1500 Spiral Tubeformer

The SBFB-1500 spiral tubeformer in 316L stainless configuration produces round spiral duct from 100 to 1500 millimetres diameter for vent stack risers, canopy ventilation drops, tube trailer loading bay extract, refuelling station canopy supplementary mechanical ventilation drops and laboratory fume hood ductwork. Round duct is preferred for long runs because of its strength-to-weight ratio and lower pressure drop. Continuous lengths up to 12 metres minimise field joints and field leakage.

18.6 SBPC1500 Plasma Cutter

The SBPC1500 plasma cutter handles 316L stainless sheet penetrations and access panel cutouts for branch take-offs, instrument tappings, access for fan and damper inspection, and the bespoke cutouts that complement the SBAL-V and SB-ZF1500 output. CNC-controlled plasma cutting delivers the accuracy and productivity required for high-volume fitting fabrication on a hub-scale project. Heavy-gauge plasma is the only practical method for cutting 316L above 6 millimetres thickness on the high-pressure vent stack root.

18.7 SBLR-600 Manual Welder

The SBLR-600 manual welder handles the field joints and the site adjustments where the prefabricated SBAL-V and SB-ZF1500 sections meet at site. The welder is configured for short-arc, pulse and TIG modes that handle thin-gauge 316L HVAC ducting without burn-through or distortion. Critical field joints in Zone 1 service require full pickle-and-passivate post-weld treatment.

18.8 SBTF-1500, SBTF-1602 and SBTF-2020 Spiral Tubeformers

The SBTF-1500, SBTF-1602 and SBTF-2020 spiral tubeformers cover the larger diameter spiral scope from 1500 to 2020 millimetres for the ammonia plant scrubber ducting, the LH2 cold box room displacement exhaust trunk, the tube trailer loading bay canopy exhaust and the methanol distillation column vent. The SBTF-2020 is the largest spiral capability in the SBKJ range, handling 316L coil up to 1.5 millimetres at 6 to 10 metres per minute.

18.9 Ex-Rated Fans, Motors and Dampers

The active electrical equipment installed in Zone 1 and Zone 2 — fan motors, volume control dampers with electric actuators, fire and smoke dampers with thermal links, hydrogen detectors, smoke detectors, pressure differential transmitters, control panels — is sourced ATEX or IECEx-certified with gas group IIC and equipment protection level Gb for Zone 1 or Gc for Zone 2. The 316L sheet metal duct itself is bonded to the plant earth grid with maximum 1 megohm continuity between any two points. Spark-resistant fan impellers in aluminium or non-sparking stainless are standard on any hazardous area extract path.

19. Climate envelope and the freight catchment around each hub

The climate envelope across the Australian hydrogen hub portfolio drives substantial variation in HVAC equipment sizing and duct insulation specification. The Pilbara WA sites at Fortescue, Yara and the proposed Port Hedland terminal sit at 45 to 50 degrees Celsius summer ambient with combined salt and humidity exposure that drives 316L stainless across most external runs and aluminium-clad insulated ductwork on the internal supply trunks. Kwinana WA and Perth metropolitan operate at lower summer ambient but with similar coastal corrosion exposure. The Hunter Valley NSW HVHH and Port Kembla NSW H2X sites operate at moderate maritime climate with chloride stress corrosion exposure that justifies the 316L over 304 specification. The Gladstone QLD and Bell Bay TAS terminals sit at coastal climates with significant humidity, with Bell Bay running cooler year-round and Gladstone running tropical. The Port Bonython SA, Whyalla SA and Eyre Peninsula SA sites operate at hot arid climate with substantial diurnal temperature swing.

Freight catchment from the SBKJ Group Box Hill North VIC fabrication base reaches the Port Kembla, Hunter Valley and Sydney scope by overnight curtain-side B-double, the Adelaide, Whyalla and Port Bonython scope by 24 hour B-double, the Bell Bay scope by Bass Strait ferry plus B-double, the Gladstone and CQ-H2 Aldoga scope by 48 hour B-double, the Kwinana, Jandakot and Perth scope by 72 hour B-double or rail, and the Pilbara scope by rail plus road train. Lead time on prefabricated 316L ductwork at the SBAL-V and SBAL-III bench is 6 to 10 weeks from contract for a full 5000 to 10000 square metre scope, with the SBSF-1525 stitchwelder closure adding 2 to 4 weeks.

20. The commissioning and ARENA Hydrogen Headstart milestone audit

The commissioning sequence for HVAC ductwork on an Australian hydrogen plant is the final and most exposed phase. On commissioning the team injects calibration hydrogen gas at three points across the electrolyser hall ceiling and verifies each detector responds within 30 seconds. The ventilation boost activates on 25 percent LEL trip. The emergency shutdown sequence runs on 50 percent LEL trip with electrolyser stack trip, blowdown initiation and control room HVAC recirculation mode. NH3 detection on the ammonia loop and methanol vapour detection on the methanol synthesis are similarly tested with calibration gas injection at the relevant grid points.

The commissioning report is witnessed by an independent third-party inspector certified under IECEx CoPC or equivalent. The HVAC system must be fully proven for 30 to 60 days before first hydrogen is admitted to the cell stacks — a credible failure on first hydrogen introduction is much more likely than during steady-state operation. The Hydrogen Headstart milestone audit pack at handover includes the HAC drawing signed by the IECEx CoPC auditor, ATEX and IECEx certificates for every active component in any zone, the AS 4254 Class A leakage certificate from the NATA-accredited inspector, the ISO 26142 detection commissioning report, the AS 1530.4 fire damper drop-test record, the Safe Work Australia WES baseline survey for hydrogen, ammonia, caustic mist, methanol vapour and oxygen, the ISO 22734 SAT report on the electrolyser package and the ISO 19880 commissioning report on the HRS scope.

The plant operator maintains the hazardous area register from handover through the asset life with every modification signed off by the IECEx CoPC auditor and re-tested for compliance. Periodic inspection runs on a 12 month visual cycle for duct external condition, fan housings, dampers and detectors. 24 month close inspection covers clearances, sealing surfaces, actuator function and detector calibration. Condition-based detailed inspection runs on any equipment showing degradation. Training of operations staff covers alarm response, manual ventilation override and isolation procedures. Training of maintenance staff covers Ex-rated equipment inspection per AS/NZS 60079.17.

21. Cross-references and related reading

The hydrogen, electrolyser, HRS, green ammonia, methanol and hydrogen hub vertical shares substantial engineering DNA with adjacent project classes but diverges on specific details. Readers working on related projects should consult the following companion guides from the SBKJ Group insights library:

• Green Hydrogen Production, Electrolyser, Ammonia and H2 Refuelling HVAC Duct Guide — the broader hydrogen vertical companion covering AEM and alternative carrier scope and the international comparison with EU and US hub builds.
• Utility-Scale Solar Farm, Big Battery BESS, Wind, Substation and REZ HVAC Duct Guide — the upstream renewable generation companion supplying the electrolyser feed power on most Australian green hydrogen projects.
• Hydrogen Production HVAC Duct Guide — the original SBKJ hydrogen production reference covering the early-stage project scope and the international standards baseline.
• SBKJ Machines Catalogue — for the complete product range including the SBAL-V, SBAL-III, SBSF-1525, SB-ZF1500, SBFB-1500, SBPC1500, SBLR-600 and SBTF-1500/1602/2020.

22. Talking to SBKJ Engineering

SBKJ Group's engineering team supports EPC mechanical leads, electrolyser OEM in-country agents, ammonia plant licensors, HRS network operators and project HVAC subcontractors from initial bid through commissioning and handover. The engagement covers bid-stage bill-of-quantities review and machine configuration recommendation, detailed design review of project HVAC drawings for fabrication compatibility, machinery supply with commissioning and operator training, remote technical support for the life of the equipment, and a 10-year spare parts continuity guarantee with stocked items shipped within 14 days to Australian destinations from Box Hill North VIC.

For project teams preparing ARENA Hydrogen Headstart milestone submissions, Australian Clean Hydrogen Industrial Hubs Program audit packs, AS/NZS 60079 hazardous area dossiers or ISO 22734 electrolyser SAT reports, SBKJ provides a ductwork scope and quality control narrative suitable for the commissioning evidence pack — covering material selection, sealing class, leakage testing, balancing, acoustic verification, AS 1530.4 fire damper test records, ISO 26142 gas detection and extract interlock test records, and as-built documentation.