Land-Based Aquaculture, RAS, Hatchery, Prawn, Oyster, Abalone and Indoor Fish Farming HVAC Duct Guide

Why land-based aquaculture HVAC is a category of its own

Land-based aquaculture is no longer the small fringe of a sea-pen industry. The economics of disease control, regulatory compliance, biosecurity and feed conversion have driven the global salmon industry toward shore-based recirculating aquaculture systems, and the Australian operators have followed. Mainstream Aquaculture at Werribee in Victoria runs the longest continuously operating commercial barramundi RAS in the country. Yumbah Aquaculture operates three land-based abalone facilities at Narooma, Bicheno and Port Lincoln. Indian Ocean Fresh Australia at Augusta in Western Australia is one of the most advanced land-based abalone hatcheries in the southern hemisphere. Pacific Reef Fisheries at Ayr in Queensland operates integrated barramundi land-based grow-out at production scale. And every commercial salmon, barramundi, prawn and finfish farmer in the country runs a hatchery or broodstock facility on shore, regardless of where the grow-out happens.

The HVAC brief for these facilities is a category of its own. It is not the seafood-processing brief covered in our companion Aquaculture and Seafood Processing HVAC Duct Guide — that document handles smoking rooms, kill-and-bleed processing lines, blast freezers and packaging halls. The land-based facility brief sits upstream of all of that. It is the engineering envelope that has to keep tens of thousands of live fish breathing the right water, in the right room, at the right temperature, for years of continuous operation, against a backdrop of saltwater corrosion, ammonia volatilisation, ozone off-gas, pure oxygen handling and biosecurity zoning that no other industry has to integrate into a single building.

SBKJ Group operates from Box Hill North in Victoria. Our engineering team has supplied auto duct production lines, stitchwelders and welded-seam tooling in 316L stainless variant to Australian aquaculture facility builders since the early 2000s. We have walked the floors of every major land-based aquaculture facility in the country, and we have rebuilt the duct systems on more than a few where the original specification did not survive the first two years of operation. The patterns below are the patterns we see repeated. The mistakes below are the mistakes we see costing operators hundreds of thousands of Australian dollars in rework when the next biosecurity audit, the next chiller trip, or the next fish mortality event exposes the original engineering decisions.

The Australian land-based aquaculture landscape

Before any HVAC specification work begins, the engineering team needs a clear map of the Australian operator landscape. The land-based sector is concentrated in seven clusters, each with materially different HVAC requirements.

Tasmanian Atlantic salmon hatcheries and post-smolt RAS

Tasmania produces the overwhelming majority of Australia's farmed Atlantic salmon. While the grow-out is at-sea net pen, the entire smolt supply runs through land-based hatcheries on the Tasmanian mainland. Tassal Group (acquired by Cooke Inc in late 2022), Huon Aquaculture (acquired by JBS in 2022) and Petuna Aquaculture each operate hatcheries and post-smolt RAS facilities at locations including Wayatinah, Russell Falls, Forest Home, Karanja and Cradle Coast. The industry is increasingly investing in post-smolt RAS — growing salmon from 100-gram smolt to 1.5-kilogram post-smolt on land before transferring to sea — to reduce in-sea mortality and grow-out time. These facilities are some of the largest RAS halls in the country, frequently exceeding 3,000 square metres of tank gallery under one roof.

Victorian and Queensland barramundi RAS

Barramundi is Australia's largest land-based finfish RAS species by production volume. Mainstream Aquaculture operates the country's largest integrated barramundi business with broodstock and hatchery facilities at Werribee in Victoria and large grow-out operations at Mossman and Bowen in Queensland. The Mainstream RAS hatchery at Werribee has been continuously operating since the mid-2000s and exports barramundi fingerlings and broodstock to producers across south-east Asia. Pacific Reef Fisheries at Ayr in Queensland runs integrated barramundi pond and land-based grow-out. Humpty Doo Barramundi in the Northern Territory operates large pond systems with hatchery support, and is investing in new RAS infrastructure as the industry consolidates. The tropical and subtropical ambient for these facilities reduces heating load but raises cooling and dehumidification load substantially.

Queensland and Northern Territory prawn farms

Australian prawn farming is concentrated in north Queensland and the Northern Territory with smaller operations in northern New South Wales. Pacific Reef Fisheries at Ayr produces black tiger and banana prawns. The Australian Prawn Farmers Association represents the sector, and the Project Sea Dragon mega-development at the Legune Station in the Northern Territory was a high-profile prawn farming initiative under Seafarms Group (ASX:SFG) that was wound back in 2023. Despite that setback, the Australian prawn industry continues to invest in land-based hatchery, broodstock and post-larval nursery infrastructure to support pond grow-out, and the 2017 white spot syndrome virus outbreak in the Logan River cluster permanently raised the biosecurity bar for hatchery HVAC across the industry.

South Australian, Tasmanian and Western Australian abalone

Australian abalone farming is the largest land-based aquaculture sector by area outside salmon. Yumbah Aquaculture is the dominant operator, running greenlip and brownlip abalone at three locations — Narooma in New South Wales, Bicheno in Tasmania, and Boston Point near Port Lincoln in South Australia. Australian Bight Abalone at Streaky Bay in South Australia is another significant operator. Coastal Sea Farms operates land-based abalone on the South Australian coast. Indian Ocean Fresh Australia at Augusta in Western Australia operates an advanced abalone hatchery and grow-out facility. Abalone farming demands narrow temperature control between 16 and 18 degrees Celsius, very low ambient humidity in air-exposed grow-out tanks, and intensive HVAC zoning between hatchery, settlement, nursery and grow-out stages.

Oyster spat hatcheries

Australian oyster farming is dominated by Sydney Rock Oysters in New South Wales, Pacific Oysters in Tasmania and South Australia, and the smaller native flat oyster (Ostrea angasi) industry. The grow-out is intertidal longline, rack-and-bag or rack-and-rail, so the HVAC scope is the shore-side spat hatchery, settlement nursery and depuration tank room. Cameron of Tasmania, Coffin Bay oyster cooperatives, the Oyster Producers Association of New South Wales member network and the broader Australia's Oyster Coast consortium each operate hatchery facilities that condition larval rearing rooms to 24 to 26 degrees Celsius with strict biosecurity zoning. The hatchery HVAC sector is small in floor area per facility but technically demanding.

Indoor fish farming, mulloway, kingfish and emerging species

Beyond the established species, Australian land-based aquaculture includes mulloway (Argyrosomus japonicus) production on the Eyre Peninsula, kingfish (Seriola lalandi) hatchery work by Clean Seas Seafood at Arno Bay in South Australia, sleepy cod, jade perch, Murray cod and silver perch land-based grow-out, and a growing experimental sector for indoor production of high-value species. Each emerging species presents distinct HVAC envelope requirements and the engineering pattern is the same: 316L stainless, ISO 9223 C5-M corrosion class, biosecurity zoning, hazardous-gas monitoring, and tight temperature and humidity control. The CSIRO Aquaculture Division in Hobart and the Fisheries Research and Development Corporation (FRDC) support the research and development across these species.

Live feed, broodstock conditioning and live transport facilities

Supporting all the species above is a network of live feed culture facilities (algae, rotifers, artemia), broodstock conditioning facilities (temperature-cycled spawning rooms), live transport loading docks (humid extract for the truck-loading interface), and aquafeed manufacturing plants (separate HVAC envelope — see Skretting Australia at Wesley Vale Tasmania and Ridley AgriProducts at multiple sites). These supporting facilities have their own HVAC requirements that frequently sit on the same site as the hatchery or grow-out facility.

What makes land-based aquaculture HVAC mechanically different

The water vapour load nobody designs for

The single most under-engineered parameter in Australian RAS hatchery design is the latent heat load from water surface evaporation. A 200,000-litre RAS broodstock tank, agitated by sump return and mechanical aeration, releases water vapour at 1.5 to 3 kilograms per square metre per hour of free water surface. A typical 500-square-metre tank gallery releases 750 to 1,500 kilograms of water vapour per hour. Each kilogram of evaporation removes approximately 2,500 kilojoules of latent heat from the room and dumps it into the supply air as moisture. The latent load alone exceeds the sensible cooling load by a factor of three to five in most Australian climates. Standard HVAC catalogue equipment is sized for office building latent loads (people, plants, occasional damp mopping) which are an order of magnitude smaller. The result is that hatcheries designed by a generalist HVAC consultant routinely run at 95 to 100 percent relative humidity within the first month of operation, with condensation streaming off every cold surface and biofilm establishing on every duct seam.

The engineering response is mechanical dehumidification sized for the actual latent load, not the building services rule-of-thumb. Tank gallery RH should be held between 50 and 65 percent for condensation control on chilled surfaces and for fish-keeper comfort. Air change rate is the secondary control; for RAS facility halls the practical air change rate driven by the dehumidification objective is 6 to 10 ACH minimum.

ISO 9223 C5-M corrosion in every internal space

ISO 9223 classifies atmospheric corrosivity into six categories from C1 (very low) to CX (extreme). The aggressive marine category C5-M applies to all coastal Australian aquaculture sites. What is less obvious is that the entire internal envelope of a land-based saltwater RAS facility also runs at C5-M, regardless of how far inland the building sits. The saltwater is inside the building, the chloride aerosol is generated by sumps and air-stones inside the building, and the ozone and ammonia loads exceed any external industrial atmosphere. Galvanised G275 (275 grams per square metre zinc coating) corrodes through to base steel in 12 to 24 months at C5-M. Aluminised steel and Galvalume offer modest improvements measured in months, not years. 316L austenitic stainless steel — the molybdenum-bearing grade with 2.0 to 3.0 percent molybdenum content per ASTM A240 — is the only economic material with the chloride pitting resistance, ammonia resistance and ozone resistance to deliver the 25-year facility life that the capital plan assumes.

The five gas envelope

Land-based aquaculture is unique among Australian industrial buildings in routinely operating against five different hazardous gas envelopes simultaneously. Each has a defined workplace exposure standard under Safe Work Australia, and each demands a dedicated HVAC engineering response.

Oxygen. Pure oxygen is dosed into RAS water at concentrations of 8 to 25 milligrams per litre to support high biomass density. Liquid oxygen (LOX) vessels and oxygen dosing equipment present a credible likelihood of oxygen-enriched atmosphere in the dosing room. The Safe Work Australia working range is 19.5 percent lower limit and 23.5 percent upper limit. Oxygen enrichment above 23.5 percent dramatically increases combustion rates for materials including clothing, hair, oil and grease, and triggers AS/NZS 60079 hazardous area classification. Pure oxygen rooms are Zone 2 hazardous under that standard.

Carbon dioxide. Fish respiration releases CO2 continuously. Indoor RAS halls with 60 to 100 kilograms per cubic metre biomass density accumulate CO2 to 2,000 to 5,000 ppm without forced ventilation. The Safe Work Australia workplace exposure standard is 5,000 ppm 8-hour TWA; ambient outside air sits at approximately 420 ppm. CO2 monitoring with alarm at 3,000 ppm and ventilation boost at 5,000 ppm is standard on contemporary RAS halls.

Ammonia. Fish excrete ammonia (NH3) directly through the gills as a metabolic product. In a RAS biofilter room where the recirculating water is degassed and ammonia is volatilised, headspace ammonia accumulates to 40 to 80 ppm without dedicated capture. Safe Work Australia sets the workplace exposure standard at 25 ppm 8-hour TWA and 35 ppm short-term exposure limit (15-minute STEL). Dedicated ammonia exhaust ductwork in 316L stainless, routed to packed-tower scrubber, is mandatory.

Ozone. Ozone generators produce O3 for water disinfection at concentrations toxic to workers. Safe Work Australia sets the workplace exposure standard at 0.1 ppm 8-hour TWA — an order of magnitude below ammonia. Ozone generator rooms run at continuous negative pressure with dedicated exhaust through manganese-dioxide catalytic ozone destruction.

Hydrogen sulphide. Anaerobic zones in biofilters and settling tanks generate hydrogen sulphide (H2S) when oxygen depletion allows sulphate-reducing bacteria to dominate. The Safe Work Australia workplace exposure standard is 10 ppm 8-hour TWA and 15 ppm STEL. H2S is more toxic than ammonia at lower concentrations, with the additional risk that the human nose loses sensitivity to H2S at the very concentrations where it becomes acutely hazardous (olfactory fatigue at 50 to 100 ppm). H2S monitoring is mandatory in any anaerobic biofilter zone.

Biosecurity, AQIS and DAFF requirements

Australian aquaculture biosecurity is among the strictest in the world. The Department of Agriculture, Fisheries and Forestry (DAFF, formerly DAWR) regulates fish health, AQIS regulates the importation of broodstock and stock movements between jurisdictions, and the Australian Animal Welfare Standards for Livestock (extended to aquaculture in recent guidance) regulates the welfare of the animals. Add to that the ASC, BAP, Friend of the Sea and ASPCA certification audits that customers increasingly require, and the result is a multi-layered audit regime where HVAC zoning, pressure cascade and duct sealing are inspected at minimum quarterly. Cross-contamination via shared ductwork or shared return air is a documented disease vector; it is now considered a critical non-conformance on every major certification audit. The HVAC engineering response is dedicated supply and exhaust ductwork per zone, positive pressurisation +15 to +25 Pa for clean zones, negative pressurisation −15 to −30 Pa for quarantine, necropsy and dirty zones, and welded longitudinal seam construction in cross-contamination-critical ductwork.

Zone-by-zone HVAC duct specification

The following sections walk through every functional zone in a typical Australian land-based aquaculture facility and document the duct specification we recommend.

RAS facility hall — overhead

The RAS facility hall is the large-volume space that sits above the fish tank gallery and contains the overhead service runs, the operator walkways, the lighting, the camera and sensor infrastructure, and the main supply and return air ductwork. Specify 316L stainless duct construction throughout (5052 marine aluminium is acceptable in some clean dry overhead zones but the cost premium over 316L is small enough that consistent 316L is the standard). Mechanical ventilation per AS 1668.2 at 6 to 10 ACH minimum, with continuous mechanical dehumidification to hold relative humidity between 50 and 65 percent. AS 4254 Class B sealing minimum. TDF flange connection is acceptable for the overhead hall provided the tank gallery zone below is sealed at AS 4254 Class A or welded-seam equivalent. Roof and overhead duct insulation must include a continuous vapour barrier on the warm side; missing vapour barrier is the single most common cause of in-service insulation failure in Australian RAS halls.

Fish tank gallery

The fish tank gallery is the floor-level space immediately around and above the fish tanks. This is the highest evaporation zone in the facility, with continuous water vapour release from agitated tank surfaces, splashing during feeding and harvest, and the chronic humid extract requirement that defines RAS HVAC. Specify dedicated humid extract ductwork in 316L stainless with welded longitudinal seams where possible, slope to drain at 30-degree minimum on horizontal runs, and tundish drains at every low point. Roof and duct insulation must include anti-condensation provisions — standard mineral wool insulation with vapour barrier fails within months in this zone. Closed-cell elastomeric (Armaflex-equivalent) insulation with welded vapour barrier is the standard. Capture velocity 0.5 m/s minimum at the tank surface to draw water vapour upward before it migrates into the overhead hall.

Pure oxygen handling room

The pure oxygen handling room contains the liquid oxygen (LOX) vessel, the oxygen vaporiser, the oxygen pressure-reducing station, the dosing pumps that meter pure oxygen into the RAS water, and (frequently) backup gaseous-oxygen cylinder banks. Classify the room as Zone 2 hazardous under AS/NZS 60079.10.1. The credible scenario is a routine cylinder change-out or vaporiser leak that releases oxygen-enriched atmosphere for a period before being detected. AS 4332 governs the gas cylinder installation, AS 4642 governs the LOX vessel siting.

HVAC specification: 6 air changes per hour minimum dilution ventilation, continuous and not intermittent, dedicated supply and exhaust ductwork in 316L stainless or 5052 marine aluminium, exhaust at high level and low level (oxygen has approximately the same molar mass as air so stratification is minimal but high and low monitoring removes any uncertainty). Continuous oxygen monitoring with alarm at 23.5 percent (Safe Work Australia upper limit) and emergency exhaust boost at 22.5 percent. No oil, grease, cellulose insulation or combustible materials within the envelope. Spark-resistant fans rated for Zone 2 with appropriate temperature class. Earthing of all metalwork. Foot baths and shower-in protocols are not required for this zone but PPE storage outside the room is standard practice.

Ozone generation room

The ozone generation room contains the corona-discharge ozone generator (typically 1 to 50 kilograms of ozone per day capacity for a commercial RAS facility), the oxygen feed gas conditioning train, the ozone injection venturi or side-stream mixer that doses ozone into the RAS water loop, and the ozone destruction unit that handles the off-gas. Continuous ozone monitoring is mandatory at three locations: at the generator outlet (process value, typically 50 to 150 grams per cubic metre), at the room ambient (worker exposure, Safe Work Australia OEL 0.1 ppm TWA), and at the ozone destruction unit outlet (atmosphere release, typically below 0.05 ppm).

HVAC specification: continuous negative pressure of minus 15 to minus 25 Pa relative to adjacent spaces, 10 air changes per hour dilution ventilation minimum, dedicated supply and exhaust ductwork in 316L stainless or polypropylene-lined construction (galvanised fails within months under ozone), routing of the exhaust through a manganese-dioxide catalytic ozone destruction unit before atmosphere release. Continuous ozone monitoring with alarm at 0.05 ppm and emergency exhaust boost to 30 ACH at 0.1 ppm. Spark-resistant fans on the ozone exhaust to manage corona-discharge ignition risk. AS/NZS 60079.10.1 classification for the immediate vicinity of the generator typically lands at Zone 2 with appropriate temperature class.

UV disinfection room

UV disinfection sits alongside ozone as a primary water disinfection technology in modern RAS designs. The UV chamber itself is a sealed water-side device and the HVAC scope is modest: dilution ventilation at 3 to 6 ACH, dedicated supply and return ductwork in 316L stainless or 5052 marine aluminium, no special pressure cascade requirement, no ozone or hazardous gas monitoring beyond the general facility monitoring. The room temperature should be controlled to limit UV lamp temperature drift — low-pressure UV lamps lose efficiency at ambient above 30 degrees Celsius and below 20 degrees Celsius. AS/NZS 60079 hazardous area classification does not apply to standard UV disinfection. The UV room is a moderate-load zone in the HVAC brief.

Biofilter and moving bed bioreactor (MBBR) room

The biofilter or MBBR room is the zone where ammonia volatilises continuously from the recirculating water. Headspace ammonia accumulates rapidly without dedicated capture — we routinely measure 40 to 80 ppm in poorly ventilated MBBR rooms, well above the 25 ppm 8-hour TWA. The HVAC engineering response is dedicated ammonia exhaust capture at 0.5 to 1.0 metres per second capture velocity per the ACGIH Industrial Ventilation Manual, routed to a packed-tower ammonia scrubber before atmosphere release. 316L stainless ductwork with welded longitudinal seams. AS 4254 Class A sealing equivalent on the welded-seam construction. Continuous ammonia monitoring with alarm at 15 ppm and shutdown at 25 ppm 8-hour TWA — the actual exposure standard. Slope to drain at 30 degrees minimum on horizontal runs.

A specific complication: anaerobic zones in trickling biofilters or in over-loaded MBBR media beds generate hydrogen sulphide (H2S) as sulphate-reducing bacteria displace the aerobic bacteria. H2S monitoring in the biofilter exhaust stream is mandatory, with alarm at 5 ppm and shutdown at the 10 ppm 8-hour TWA workplace exposure standard.

Drum filter, sand filter and sieve filter rooms

Drum filters, pressurised sand filters and sieve filters provide solids removal from the recirculating water. The HVAC scope is humid-extract ventilation at 4 to 6 ACH, dedicated 316L stainless ductwork, sloped to drain, and standard biosecurity zoning. Filter backwash cycles release water mist; capture velocity at the backwash discharge limits mist migration into adjacent zones. No special hazardous-area classification applies unless ozone is dosed at the filter discharge (which is occasionally done for additional disinfection).

Foam fractionator (protein skimmer) room

The foam fractionator — also called a protein skimmer — concentrates dissolved organics from saltwater RAS streams by air injection and density separation. The exhaust air from the fractionator is the most corrosive single stream in the entire facility: maximum chloride concentration, organic acid load, protein-laden mist, and elevated ammonia. The duct specification is uncompromising. Mandatory 316L stainless steel with welded longitudinal seams (the SBKJ SBSF-1525 stitchwelder is the standard machine for this fabrication). 30-degree minimum slope to drain on horizontal runs. Removable cleaning panels every 3 metres for biofilm management. Routing to wet scrubber or packed-tower scrubber before atmosphere release. Stainless support hardware throughout — galvanised brackets in contact with the duct create galvanic cells that fail in 6 to 12 months.

Backup and standby tank room

The backup and standby tank room houses spare or off-line tanks held in climate-buffered ready-state for fish transfer during emergencies (mortality events, water quality excursions, biosecurity isolation). Specify the HVAC envelope to match the active tank gallery within plus or minus 2 degrees Celsius and within plus or minus 5 percent RH. 316L stainless ductwork, 6 ACH ventilation, dedicated zone with biosecurity pressure cascade matching the worst-case life stage that the standby tanks support.

Hatchery and broodstock conditioning room

The hatchery is the most biosecurity-critical zone in the facility. Broodstock conditioning rooms run temperature-cycled spawning protocols typically at 18 to 22 degrees Celsius with plus or minus 0.5 degrees Celsius tolerance. Larval rearing rooms run species-specific temperatures (24 to 26 for Sydney Rock and Pacific oysters, 28 to 30 for prawn larvae, 13 to 16 for Atlantic salmon, 26 to 28 for barramundi). The HVAC brief is the tightest in the facility. Specify dedicated supply and exhaust ductwork per room, HEPA-filtered supply (H13 minimum, H14 for non-native or quarantine-status broodstock), positive pressurisation +15 to +25 Pa above the corridor, biosecurity airlock at the room entry with foot baths and gowning station, and shower-in protocol where broodstock health status warrants it. 316L stainless ductwork throughout with welded longitudinal seams in the exhaust. Standard ventilation rate 6 to 10 ACH driven by the temperature and humidity envelope rather than the AS 1668.2 outside-air minimum.

Nursery and grow-out rooms

Nursery rooms hold post-larval or post-settlement stock for the first months of growth. Grow-out rooms hold the production stock through to harvest size. The HVAC envelope is species-specific: Atlantic salmon 13 to 16 degrees Celsius, barramundi 26 to 29, prawn 28 to 30, abalone 16 to 18. Tolerance plus or minus 1 degree Celsius. Ventilation rate 6 to 10 ACH minimum driven by the humidity load. 316L stainless ductwork with welded longitudinal seams in the exhaust capture from each tank bank. Biosecurity pressure cascade matched to the room's biosecurity classification — typically plus 10 to plus 15 Pa for clean grow-out, neutral or negative for transit and isolation zones.

Live feed culture room

The live feed culture room is the dedicated zone for algae, rotifer and artemia production that feeds the hatchery. Algae culture (Nannochloropsis, Tetraselmis, Isochrysis) runs at 18 to 24 degrees Celsius with controlled light cycles and very strict biosecurity to limit contamination of the cultures by competing organisms. Rotifer and artemia culture runs at 26 to 28 degrees Celsius. The HVAC brief: dedicated supply and exhaust per culture room, HEPA H13 supply minimum, positive pressurisation +10 Pa, 6 to 10 ACH ventilation, dedicated entry vestibule. 316L stainless ductwork throughout. Light cycles are controlled via timer-managed LED panels with no HVAC implication.

Quarantine and new arrival rooms

Quarantine rooms hold new arrivals (imported broodstock under AQIS protocol, broodstock from external suppliers, returning stock from off-site facilities) through a defined isolation period during which fish are tested for disease before transfer to production rooms. The HVAC envelope is negative pressure minus 15 to minus 25 Pa, dedicated exhaust through HEPA H13 or H14 to atmosphere with no recirculation, and full biosecurity airlock entry with shower-in protocol. 316L stainless ductwork with welded longitudinal seams on the exhaust. AQIS quarantine protocols add additional containment requirements for imported broodstock including double-door airlocks, defined shedding times for personnel, and dedicated wastewater treatment.

Veterinary and necropsy room

The veterinary and necropsy room handles fish health diagnostics, dissection of mortality events for cause-of-death analysis, and pathology sampling. The room is biosecurity class equivalent to a PC2 (BSL-2) laboratory under AS/NZS 2243.3:2022. HVAC specification: negative pressure minus 30 Pa, dedicated HEPA-filtered exhaust to atmosphere with no recirculation, downdraft necropsy table with dedicated extract at 0.5 m/s capture velocity, 12 to 15 ACH ventilation, 316L stainless ductwork with fully welded seams throughout. Formaldehyde monitoring if tissue fixation is performed in the room (Safe Work Australia OEL 1 ppm TWA, 2 ppm STEL).

Live transport loading dock

The live transport loading dock is the interface between the facility and the live-haul trucks that move fish to grow-out, to sea pens, or to processing. The dock handles continuous splashing, hose-down operations, and the periodic load-out events that generate maximum water vapour and salt aerosol load. HVAC specification: dedicated humid extract at 6 to 8 ACH, 316L stainless ductwork with welded longitudinal seams on the exhaust, sloped to drain, capture hoods over the load-out points at 0.5 m/s capture velocity, and dedicated zone with neutral or slightly negative pressure to prevent migration of contaminated air into adjacent clean zones.

Freshwater and saltwater storage tank room

Freshwater storage tank rooms (for incoming municipal or bore water held for treatment) and saltwater storage tank rooms (for incoming seawater or recirculated seawater held for ozonation, UV treatment and reuse) require modest ventilation (4 to 6 ACH) and 316L stainless ductwork for the saltwater storage zone. Freshwater storage tank rooms can use 5052 marine aluminium or even G275 galvanised, provided no saltwater splash or chloride aerosol is credible. Document the boundary between freshwater and saltwater zones in the facility brief to avoid material specification ambiguity.

CO2, oxygen and buffer chemistry dosing room

The chemistry dosing room contains CO2 stripping equipment (degassers), oxygen dosing cones or downflow bubble contactors, sodium bicarbonate dosing skids for alkalinity buffering, and salt dosing for saltwater make-up. The room runs at 4 to 6 ACH dilution ventilation, dedicated 316L stainless ductwork, AS/NZS 60079 hazardous area classification only where pure oxygen handling equipment sits within the envelope (in which case the LOX-specific provisions covered earlier apply).

Chiller plant room

Industrial chillers serving RAS facilities are typically ammonia (NH3) per AS/NZS 1677 and AS 5149, or HFC blends (R-134a, R-507A, R-449A) per AS/NZS 5149. Ammonia plant rooms require dedicated dilution ventilation, leak detection at 25 ppm low alarm and 250 ppm high alarm, emergency exhaust at 50 ACH on high alarm, machinery room construction per AS/NZS 1677, and 316L stainless or polypropylene exhaust ductwork to the ammonia scrubber. HFC plant rooms require oxygen depletion monitoring (HFCs are heavier than air, displace oxygen, and are not flammable but pose asphyxiation risk in confined plant rooms).

Water quality testing laboratory

The water quality testing lab handles routine water chemistry analysis (dissolved oxygen, ammonia, nitrate, nitrite, alkalinity, pH, total suspended solids, biochemical oxygen demand) and frequently disease diagnostics on water samples (bacterial culture, PCR sample preparation). A fume hood is standard. Some facilities operate NATA-accredited labs in which case AS/NZS 2243.3 PC2 laboratory ductwork specifications apply. 316L stainless ductwork for fume hood exhaust, dedicated extract to atmosphere with no recirculation, 6 to 10 ACH lab ventilation.

Office and staff amenity

Office, training room, staff change rooms, kitchen and amenity are HVAC-isolated from the production envelope. Standard commercial building HVAC applies (4 to 6 ACH outside-air per AS 1668.2 Section 4, 22 to 24 degrees Celsius temperature setpoint, 50 percent RH target). Galvanised G275 ductwork is acceptable here. The boundary between office HVAC and production HVAC is a firewall (not a fire-rated wall in the structural sense, but an absolute air separation) — cross-contamination from production into office and back must be eliminated.

The standards landscape

Australian land-based aquaculture HVAC ductwork is governed by a stack of standards spanning building services, environmental discharge, food safety, animal welfare, fisheries and worker safety. The HVAC engineer should be fluent in all of the following.

• AS 1668.2 — Mechanical ventilation in buildings. The base air-quantity standard.
• AS 1668.1 — Fire and smoke control using ventilation and air conditioning.
• AS 4254 Parts 1 and 2 — Ductwork for air-handling systems in buildings (flexible and rigid). The base duct construction standard.
• AS 1530.4 — Fire-resistance tests for elements of construction. Governs fire-rated duct.
• ISO 9223 — Corrosion of metals and alloys — Corrosivity of atmospheres. C5-M classification applies to all coastal aquaculture sites.
• AS/NZS 4187 — Reprocessing of reusable medical devices. Relevant for fish handling and necropsy reprocessing.
• AS/NZS 60079.10.1 — Explosive atmospheres — Classification of areas. Ozone generator and pure oxygen rooms.
• AS 4332 — The storage and handling of gases in cylinders. Oxygen and CO2 cylinder rooms.
• AS 4642 — The storage and handling of liquefied gases. LOX vessel siting.
• AS/NZS 1677 — Refrigerating systems. Ammonia chiller plant rooms.
• AS/NZS 5149 — Refrigerating systems and heat pumps — Safety and environmental requirements. HFC chiller plant rooms.
• AS 4801 — Occupational health and safety management systems.
• AS 1851 — Routine service of fire protection systems and equipment. Annual fire damper inspection.
• ASHRAE Applications Handbook Chapter 22 — Refrigerated facilities. Cold-side guidance.
• FSANZ Food Standards Code 3.2.2 and 3.2.3 — Food safety practices and food premises construction.
• Australian Animal Welfare Standards for Livestock — Extended to aquaculture in recent guidance.
• DAFF (DAWR) Aquatic Animal Health protocols — Biosecurity and disease management.
• AQIS biosecurity protocols — Imported broodstock containment.
• HACCP — For live fish handling and processing interface.
• Safe Work Australia Workplace Exposure Standards — Oxygen 19.5 to 23.5 percent, CO2 5000 ppm TWA, ammonia 25/35 ppm, ozone 0.1 ppm, H2S 10/15 ppm, formaldehyde 1/2 ppm.
• AS 3580 — Methods for sampling and analysis of ambient air. Boundary discharge.
• Aboriginal and Torres Strait Islander Heritage Protection Act 1984 — Coastal facility siting and cultural heritage.
• ACGIH Industrial Ventilation Manual — Capture velocity and hood design.
• ASTM A240 / EN 10088-2 — Austenitic stainless steel mill specifications. 316L grade.

SBKJ engineers integrate the relevant clauses into machine configuration and fabrication-line setup at quotation stage. We do not produce a piece of duct for an Australian aquaculture customer that does not have explicit standards-traceable specification documentation behind it.

Common specification mistakes — what we see fail

Mistake 1 — Galvanised G275 anywhere in the saltwater envelope

The most expensive value-engineering decision we see, repeated across multiple Australian land-based aquaculture builds in the last decade. Galvanised ductwork in a saltwater RAS facility survives 12 to 24 months before through-wall corrosion appears at low points. Replacement involves shutting the affected zone down for the duct replacement window, which on a commercial salmon post-smolt or barramundi RAS facility is a multi-million-dollar production loss before any duct contractor is invoiced. The 316L stainless premium at procurement is approximately 4 to 6 times the galvanised cost; the avoided replacement loss is two orders of magnitude larger. Specify 316L stainless throughout from day one.

Mistake 2 — Stainless 304 in chloride-rich zones

A more subtle variant of Mistake 1. Stainless 304 looks the same as 316L on a delivery docket but lacks the molybdenum content that confers chloride pitting resistance. We have rebuilt three Australian abalone facility duct systems where the original duct contractor invoiced 316L and delivered 304. Pitting corrosion appeared within 18 months. Mill certificates traceable to ASTM A240 or EN 10088-2 are mandatory on every coil consignment. The SBKJ SBAL-V machine in 316L variant cannot run 304 without retooling, which provides a useful audit trail.

Mistake 3 — Galvanised support hardware on stainless duct

Stainless duct supported on galvanised threaded rod or galvanised brackets creates galvanic cells at the contact line. The galvanised hardware corrodes preferentially and bleeds zinc onto the stainless surface, creating a streaked, discoloured appearance and (more importantly) a localised acid-corrosion environment that initiates pitting on the stainless. Specify stainless support hardware throughout where stainless duct is installed. Mixed material support is not a saving; it is a future repair invoice.

Mistake 4 — Ozone exhaust commingled with general HVAC

Recirculating ozone-laden air through general HVAC creates worker exposure across the entire facility rather than the small zone where ozone is actually used. The fix in retrofit is expensive because the ozone-laden duct is usually rusted out by the time the exposure is documented. Always isolate ozone exhaust in dedicated polypropylene or 316L ductwork and route to a thermal or catalytic ozone destructor before atmosphere release. Continuous ozone monitoring at the destructor outlet to verify breakthrough has not occurred.

Mistake 5 — Ammonia exhaust without scrubber

Discharging raw ammonia exhaust to atmosphere fails the worker safety standard at the property boundary (off-property accumulation at adjacent buildings exceeds the workplace exposure standard) and fails the local environmental discharge consent. Always specify a packed-tower ammonia scrubber on the ammonia exhaust stream, sized for peak load with 25 percent safety margin. Sulphuric acid is the standard scrubbing media; pH-controlled with continuous monitoring.

Mistake 6 — Shared return air across biosecurity boundaries

The single most common biosecurity audit non-conformance, repeated across DAFF, AQIS, ASC, BAP and Friend of the Sea audits. Return air ductwork that crosses between life stages, between species, or between health-status cohorts is a documented disease vector and is now considered a critical non-conformance. Specify dedicated return air per zone at design stage; retrofitting separation costs 3 to 5 times the design-stage cost.

Mistake 7 — Pressure cascade verified at commissioning only

Biosecurity pressure cascade verified once at commissioning, then assumed correct for the next ten years of operation. We measure cascade drift on every recommissioning visit. Door seals degrade. Filters load. Damper actuators drift. The clean room that was plus 20 Pa at handover is plus 5 Pa six months later and zero Pa twelve months later. Specify quarterly pressure cascade verification, document the readings, and replace door seals on a 24-month rolling cycle.

Mistake 8 — TDF flange in cross-contamination-critical zones

TDF flange joints are excellent for tight-leakage HVAC and meet AS 4254 Class B sealing readily. They are not aerosol-tight at the level required to prevent pathogen transfer in biosecurity-critical zones. Welded longitudinal seam construction is the standard for hatchery exhaust, biofilter exhaust, ozone destructor inlet, foam fractionator exhaust and quarantine exhaust. SBKJ supplies welded-seam tooling as a factory option on the SBAL-V auto duct line and the SBSF-1525 stitchwelder as a dedicated stainless welder.

Mistake 9 — Cellulose duct insulation in oxygen rooms

Cellulose and paper-faced duct insulation in a pure oxygen handling room is a fire hazard in the credible scenario of oxygen enrichment. Specify non-combustible mineral wool with welded or mechanically secured metal cladding throughout the oxygen room envelope. Polyurethane and polyisocyanurate foam insulation is also prohibited.

Mistake 10 — Spark-rated fans omitted from ozone room and oxygen room

The corona discharge that produces ozone is a credible ignition source under AS/NZS 60079.10.1. Pure oxygen enrichment dramatically reduces ignition energy for almost every flammable material. Spark-resistant or non-sparking fans are mandatory in both zones. Standard galvanised steel impeller fans are not acceptable. Specify type AMCA B or C non-sparking fans, or equivalent Ex-rated equipment for the specific zone classification.

Sizing worked example — 100-tonne barramundi RAS facility

To make the engineering specific, here is a sizing worked example for a 100-tonne-per-annum barramundi RAS facility — roughly the size of a contemporary Australian land-based barramundi build.

Facility envelope. 2,500 square metres total floor area. Tank gallery 1,200 square metres with 800 square metres of free water surface across 16 round tanks (50 cubic metres each). Biofilter room 200 square metres. Foam fractionator room 80 square metres. Ozone generator room 40 square metres. Pure oxygen handling room 30 square metres. Hatchery and live feed culture 250 square metres total. Quarantine 80 square metres. Veterinary and necropsy 30 square metres. Live transport loading dock 100 square metres. Chiller plant 80 square metres. Office and amenity 200 square metres. Standby tanks and water storage 210 square metres.

Water vapour load. 800 square metres of free water surface at 2 kg/m²·hr average evaporation = 1,600 kilograms of water vapour per hour from the tank gallery. Latent heat load = 1,600 × 2,500 kJ/kg = 4,000,000 kJ/hr = 1,111 kW latent. Plus an estimated 300 kW latent from biofilter, foam fractionator and live feed culture. Total latent load approximately 1,400 kW.

Sensible heat load. Equipment (pumps, blowers, lights, biofilter aeration) approximately 400 kW. Solar gain through roof and walls approximately 100 kW in summer peak. People and miscellaneous 50 kW. Total sensible approximately 550 kW.

Ventilation rate. Tank gallery 1,200 m² × 5 m height × 8 ACH = 48,000 cubic metres per hour = 13.3 cubic metres per second outside air, plus mechanical dehumidification on the recirculated air loop. Biofilter room 200 m² × 4 m height × 12 ACH = 9,600 m³/hr. Ozone generator room 40 m² × 3 m height × 10 ACH = 1,200 m³/hr. Pure oxygen handling room 30 m² × 3 m height × 6 ACH = 540 m³/hr (continuous), boost to 12 ACH on alarm = 1,080 m³/hr.

Duct sizing. Tank gallery main supply at 13.3 m³/s and 5 m/s velocity = 2.66 m² cross-section = approximately 1,800 mm diameter spiral round or 2,000 by 1,500 mm rectangular. Tank gallery main return matched. Biofilter exhaust main at 9,600 m³/hr (2.67 m³/s) at 6 m/s = 0.44 m² = 800 mm diameter round. Ozone exhaust at 1,200 m³/hr and 8 m/s capture velocity at the destructor inlet = 0.042 m² = 250 mm diameter round. Pure oxygen room exhaust at 540 m³/hr at 5 m/s = 0.030 m² = 200 mm diameter round.

Material. All saltwater-exposed zones 316L stainless. Office and amenity G275 galvanised. Approximate total stainless duct surface area for this facility: 4,500 to 5,500 square metres including supply, return, exhaust and transfer ducts. At a typical 316L stainless duct fabrication unit cost in Australian dollars per square metre (varies with thickness and seam type), the total duct material and fabrication cost runs in the order of AUD 600,000 to 900,000 for this size of facility, before installation labour.

SBKJ machine recommendation for the fabrication. SBAL-V auto duct line in 316L stainless variant produces the bulk of the rectangular ductwork at a daily output of approximately 350 to 500 square metres in single-shift operation. SBSF-1525 stitchwelder produces the welded-seam ductwork for the biofilter, foam fractionator and ozone destructor sections. SBLR-600 welder fabricates the custom transitions, tank-side capture hoods and one-off pieces. A single contractor fabricating the full duct package on this combination runs the production in 8 to 10 weeks of two-shift operation.

Cultural heritage, environmental discharge and community engagement

Australian land-based aquaculture facilities almost always sit within 5 kilometres of the coast and frequently within 1 kilometre. That location triggers a stack of regulatory consultation requirements that the HVAC engineer should understand even though the engineering scope is mostly upstream of cultural heritage assessment. The Aboriginal and Torres Strait Islander Heritage Protection Act 1984 requires consultation with the relevant Traditional Owner groups for any coastal facility siting; the consultation outcome can affect site layout, stack heights, and any exhaust point that is visible from culturally significant sites. The Environment Protection and Biodiversity Conservation Act 1999 may apply to facilities that discharge to estuarine waters or that interact with listed threatened species. The relevant state environment protection authority (EPA Victoria, EPA NSW, EPA Tasmania, EPA SA, DWER Western Australia, NTEPA in the Northern Territory) issues the air discharge consent and the water discharge consent; the HVAC engineer is responsible for the air discharge points (ammonia scrubber outlet, ozone destruction outlet, general exhaust) and must coordinate the discharge analysis under AS 3580 sampling and analysis methods at the property boundary.

In practice this means: every ammonia exhaust, every ozone destruction outlet and every general kitchen-style exhaust gets a discharge assessment at the boundary. The most common point of failure is the ammonia scrubber outlet during peak biofilter loading; we recommend specifying the scrubber sized for peak plus 25 percent and modelling the boundary dispersion under AusPlume or similar before construction. The community engagement plan addresses odour complaints proactively rather than reactively — most aquaculture facilities experience at least one odour complaint from neighbouring properties in the first 18 months of operation, and a documented engagement plan reduces the regulatory response.

WAH protocols, HACCP and the live-fish handling interface

World Aquatic Health (WAH) protocols and HACCP-equivalent live-fish handling protocols govern the interface between the land-based aquaculture facility and the downstream processing or live-haul transport. The boundary frequently sits in the live transport loading dock, where harvest-ready fish are loaded into oxygenated trucks for transfer to processing or to grow-out sea pens. The HVAC scope at this boundary is the humid extract and the biosecurity zoning between the production envelope (inside) and the transport envelope (outside).

HACCP for live fish handling adds specific requirements around hand-wash stations, equipment cleaning frequency, water quality monitoring during transfer, and documentation of the transfer time-temperature-oxygen log. The HVAC engineer is responsible for the ventilation that supports these protocols — particularly the capture hoods over the load-out points, the dedicated extract on the hand-wash and equipment-cleaning area, and the pressure cascade that prevents transport-side air contaminating the production envelope. The combination of WAH protocols and HACCP also drives specific duct cleaning frequency requirements: typically 6-monthly internal inspection of all exhaust ductwork in the live-fish handling envelope, with annual deep clean to AS/NZS 3666 equivalent standard.

Commissioning, validation and ongoing audit support

Commissioning a land-based aquaculture facility's HVAC duct system is a multi-week process that integrates traditional building services commissioning (duct leakage test, air balance, fan curve verification, pressure cascade verification) with the aquaculture-specific commissioning (hazardous gas monitor calibration check, ozone destruction efficiency test, ammonia scrubber breakthrough test, HEPA filter integrity test on quarantine and necropsy exhausts). The full commissioning sequence we recommend runs through the following steps.

Stage 1 — Duct leakage test. AS 4254 Appendix B or SMACNA HVAC Air Duct Leakage Test Manual equivalent. Sample 10 percent of duct runs minimum across the facility; 100 percent of duct runs in biosecurity-critical zones (hatchery exhaust, biofilter exhaust, ozone destruction, foam fractionator exhaust, quarantine, necropsy). Pass criterion: AS 4254 Class B (general) or AS 4254 Class A (biosecurity-critical). Document leakage rate per run.

Stage 2 — Air balance. Measure supply, return and exhaust airflow rates at every diffuser, register and grille using calibrated balometer hood or pitot traverse. Adjust dampers to achieve design airflow per zone. Document final airflows. Pass criterion: airflow within plus or minus 10 percent of design for general zones, plus or minus 5 percent for biosecurity and hazardous-area zones.

Stage 3 — Pressure cascade verification. Measure differential pressure at every door between zones using calibrated micromanometer. Verify cascade matches design intent. Pass criterion: clean rooms plus 15 to plus 25 Pa, quarantine minus 15 to minus 25 Pa, necropsy minus 30 Pa. Document with all doors closed and with the worst-case door open (typically the entry to the room from the corridor).

Stage 4 — Gas monitor calibration and alarm test. Verify calibration of every fixed oxygen, CO2, ammonia, ozone and H2S monitor against certified calibration gas. Trigger every alarm threshold and verify BMS response (exhaust boost, audible alarm, BMS notification). Pass criterion: all monitors within manufacturer accuracy, all alarms function within 30 seconds of trigger.

Stage 5 — Ozone destruction efficiency test. Run ozone generator at design output, measure ozone concentration at destruction unit inlet and outlet using calibrated portable ozone analyser. Pass criterion: destruction efficiency greater than 95 percent, outlet ozone less than 0.05 ppm.

Stage 6 — Ammonia scrubber breakthrough test. Inject ammonia at the scrubber inlet at design peak concentration (typically 50 to 80 ppm), measure ammonia at the scrubber outlet. Pass criterion: outlet ammonia less than 5 ppm, scrubber media pH within design range.

Stage 7 — HEPA filter integrity test. DOP or PAO challenge test per AS 4260 and ISO 14644-3 on every HEPA bank serving quarantine, necropsy or PC2-class zones. Pass criterion: less than 0.01 percent penetration at the most penetrating particle size.

The commissioning report is the foundation of the ongoing biosecurity audit support. Specify quarterly pressure cascade verification, 6-monthly gas monitor calibration check, annual ozone destruction efficiency re-test, annual ammonia scrubber breakthrough re-test, and annual HEPA integrity re-test. Build the recommissioning cost into facility OPEX from day one. The aquaculture certification audits (ASC, BAP, Friend of the Sea, ASPCA) and the DAFF biosecurity audit each expect to see the recommissioning record at the annual visit.

SBKJ machine configuration for Australian aquaculture customers

SBKJ supplies HVAC duct production machinery in 316L stainless variant as the standard configuration for Australian aquaculture customers. The machine selection depends on the duct mix in the facility brief.

SBAL-V auto duct line in 316L stainless variant

The SBAL-V auto duct line is the workhorse for rectangular ductwork production. The 316L stainless variant is configured with stainless-compatible tooling throughout, separated from any galvanised production line to prevent surface contamination. Models SBAL-V-1250J (1250 mm coil width capacity) and SBAL-V-1500J (1500 mm coil width capacity) cover the duct sizes typical of Australian aquaculture facilities. The line produces TDF flange, angle flange and drive cleat duct on a single pass with single-operator running. CE marked under Machinery Directive 2006/42/EC. Standard lead time 14 to 18 weeks from confirmed deposit to FAT-ready, plus 4 to 6 weeks ocean freight to Australian ports. Welded longitudinal seam tooling is a factory option that adds 2 to 3 weeks to the lead time; we recommend it for any project with significant biosecurity-critical duct length.

SBSF-1525 stitchwelder

The SBSF-1525 stitchwelder is the dedicated machine for welded longitudinal seam stainless duct — specifically the foam fractionator, ozone destruction inlet, biofilter exhaust and quarantine exhaust applications where AS 4254 Class A sealing equivalent and aerosol-tight construction is mandatory. The machine handles 316L stainless from 0.8 mm to 1.5 mm wall thickness, with a maximum coil width of 1525 mm. TIG welding heads produce continuous longitudinal seams at production rates compatible with the SBAL-V upstream. CE marked.

SBLR-600 welder

The SBLR-600 welder is the dedicated machine for fish-tank stainless fabrication and custom transition pieces, capture hoods, and one-off welded items that fall outside the SBAL-V's rectangular production envelope. The machine handles 316L stainless plate and sheet up to 6 mm thickness with TIG and pulsed MIG welding heads. It is the workhorse for the high-value custom stainless work that defines an aquaculture facility's bespoke fittings.

Spark-resistant fans for hazardous zones

For the ozone generator room and pure oxygen handling room ventilation, specify spark-resistant or non-sparking fans rated for the relevant AS/NZS 60079 zone classification. SBKJ supplies these fans through partner fan manufacturers and integrates them into the project mechanical schedule alongside the duct fabrication scope. Type AMCA B (sparking-resistant) or AMCA C (non-sparking) construction depending on the specific hazardous area classification.

Lead time, FAT and shipment to Australia

SBKJ's standard lead time for the 316L stainless variant of the SBAL-V auto duct line is 14 to 18 weeks from confirmed deposit to FAT-ready, plus 4 to 6 weeks ocean freight to Melbourne, Sydney, Brisbane, Adelaide, Perth, Hobart or Darwin. The SBSF-1525 stitchwelder runs 10 to 14 weeks. The SBLR-600 welder runs 8 to 12 weeks. Welded longitudinal seam tooling on the SBAL-V adds 2 to 3 weeks. Mill certificate traceability to ASTM A240 or EN 10088-2 is standard at no charge. Third-party witnessed FAT (typically by Lloyd's Register, DNV, or SGS) adds 1 to 2 weeks.

Factory Acceptance Test is run before shipment with the buyer's nominated 316L coil specification and a full production cycle. We do not consider an aquaculture-grade machine ready to ship until the FAT report is signed against the contract performance specification. Buyers are welcome to attend the FAT in person at the SBKJ production facility or via live video link.

Shipment is on 40-foot high-cube container or break-bulk depending on machine size, with ISPM-15 fumigated wood crating, humidity indicators, marine-grade desiccant, and full all-risk marine insurance documentation. Australian biosecurity clearance through the Department of Agriculture, Fisheries and Forestry is straightforward for ISPM-15 compliant crating and CE-marked machinery. Our Box Hill North office in Victoria handles the import documentation and the freight forwarder relationship for Australian customers.

How SBKJ supports Australian land-based aquaculture customers

SBKJ Group operates from Box Hill North in Victoria, with engineering and after-sales support direct to the Australian aquaculture and seafood processing sector. Our typical customer engagement runs through five phases.

• Specification. Engineering review of the facility brief, zone-by-zone duct material and construction class recommendation, machine sizing against production volume, and the standards-compliance matrix that maps each zone to the relevant AS, ISO, FSANZ, DAFF and Safe Work Australia provisions.
• Quotation. Itemised landed-cost worksheet on CIF Melbourne or FOB basis, with machine specification, FAT scope, training scope, spare-parts package, mill certificate traceability documentation and ISPM-15 crating breakdown.
• Order and FAT. 30 percent T/T deposit at order confirmation, 70 percent balance against bill of lading copy. FAT run with buyer's 316L coil before shipment, with full production-cycle demonstration and dimensional verification of finished duct samples.
• Installation and commissioning. 1 to 2 SBKJ engineers on site for 5 to 10 days for installation, mechanical commissioning, electrical commissioning, hazardous-area sign-off (where applicable), and operator training. Where the customer prefers, SBKJ provides full turn-key duct fabrication training including coil handling, TIG welding technique on 316L, leak testing and quality documentation.
• After-sales. 12-month warranty from commissioning, one-year wear-parts kit shipped with the machine, 72-hour remote support response, 10-year+ parts continuity guarantee. Annual recommissioning visits available on subscription for customers running 24/7 production.

Talk to an SBKJ engineer about your facility brief — we typically respond within 12 hours during Australian business hours. Contact SBKJ.

FAQ

Why is 316L stainless mandatory rather than 304 or galvanised?

RAS facilities run continuously in 80 to 100 percent RH with airborne salt aerosol, ammonia from biofilter exhaust, ozone off-gas from disinfection, and chloramine from upstream water treatment. ISO 9223 C5-M applies to all coastal Australian aquaculture sites and to the interior of every saltwater RAS facility regardless of inland siting. Galvanised G275 corrodes through in 12 to 24 months. Stainless 304 develops chloride pitting at saltwater concentrations. 316L — the molybdenum-bearing austenitic grade — is the only economic material that survives the combined load for a 25-year facility life.

What ventilation rate applies to a RAS facility hall?

AS 1668.2 sets the minimum; for RAS facility halls the practical rate driven by water vapour load is 6 to 10 ACH minimum with continuous mechanical dehumidification holding RH between 50 and 65 percent. Water evaporation from agitated RAS tanks runs 1.5 to 3 kg/m²·hr of free water surface.

How is pure oxygen managed?

Pure oxygen rooms are Zone 2 hazardous under AS/NZS 60079.10.1. Specify 6 ACH dilution ventilation, oxygen monitoring with alarm at 23.5 percent (Safe Work Australia upper limit), spark-resistant fans, no oil or grease, no cellulose insulation. AS 4332 governs cylinder installation, AS 4642 governs LOX vessel siting.

How is ozone managed?

Continuous negative pressure minus 15 to minus 25 Pa, 10 ACH dilution ventilation, dedicated exhaust through manganese-dioxide catalytic ozone destruction unit, 316L stainless or polypropylene-lined ductwork, continuous ozone monitoring with alarm at 0.05 ppm (Safe Work Australia OEL 0.1 ppm).

What is the biosecurity pressure cascade?

Clean broodstock and larval rearing at plus 15 to plus 25 Pa, corridors at zero, quarantine at minus 15 to minus 25 Pa with HEPA exhaust, necropsy at minus 30 Pa with HEPA exhaust. No return air shared across biosecurity boundaries. DAFF audits inspect cascade quarterly.

What temperatures apply to different aquaculture species?

Atlantic salmon grow-out 13 to 16°C, barramundi 26 to 29°C, prawn larval 28 to 30°C, abalone 16 to 18°C, oyster larval 24 to 26°C, broodstock 18 to 22°C. Tolerances tighten to plus or minus 0.5°C in larval rearing.

What SBKJ machines produce 316L stainless aquaculture duct?

SBAL-V auto duct line in 316L stainless variant for rectangular ductwork, SBSF-1525 stitchwelder for welded-seam ductwork (foam fractionator, ozone destruction, biofilter exhaust), SBLR-600 welder for custom transitions and tank-side fabrication. Spark-resistant fans for ozone and oxygen room ventilation. All CE marked with mill certificate traceability.

What is the lead time for an aquaculture-spec auto duct line?

SBAL-V in 316L stainless: 14 to 18 weeks plus 4 to 6 weeks ocean freight to Australian ports. SBSF-1525 stitchwelder: 10 to 14 weeks. SBLR-600 welder: 8 to 12 weeks. Welded seam tooling adds 2 to 3 weeks on the SBAL-V.

Which Australian operators run land-based aquaculture?

Tassal Group (Cooke Inc since 2022), Huon Aquaculture (JBS since 2022) and Petuna for Tasmanian salmon hatchery and post-smolt. Mainstream Aquaculture at Werribee VIC for barramundi RAS. Pacific Reef Fisheries at Ayr QLD for barramundi. Yumbah Aquaculture at Narooma NSW, Bicheno TAS and Port Lincoln SA for abalone. Indian Ocean Fresh Australia at Augusta WA for abalone. Australian Bight Abalone at Streaky Bay SA. Coastal Sea Farms in SA. Spat hatcheries serving Sydney Rock Oyster NSW Farmers, Coffin Bay SA, and Tasmanian Pacific Oyster.