Wholesale Fresh Produce Market and Fish Market HVAC Duct Guide — Trading Floor, Cold Room Banks, Banana Ripening, Flower Cool, Ammonia Plant and Fish Waste Extract

Why a wholesale market is the hardest HVAC problem in commercial cold chain

A modern Australian wholesale fresh produce market is the most demanding piece of commercial HVAC infrastructure outside a hospital. The Sydney Markets at Flemington occupy 720 hectares and trade more than three million tonnes of fruit, vegetables and flowers a year through 2500 wholesalers and grower-direct stallholders. The Melbourne Market Authority at Epping, which relocated from Footscray in 2015 onto a 71-hectare site, handles roughly 60% of Victoria's fresh produce. Brisbane Markets at Rocklea, Adelaide Produce Markets at Pooraka, Perth Markets at Canning Vale, the smaller Hobart Showgrounds Market at Glenorchy and the regional North Queensland Markets at Cairns, Mackay Wholesale Markets, Townsville Markets and Sunshine Coast Wholesale Markets all operate the same operational pattern: a vast trading floor that runs from 03:00 to 11:00, surrounded by a bank of multi-temperature cold rooms holding produce, fish and frozen product across a 30-degree-Celsius span, with banana ripening rooms, flower cool rooms, ammonia compressor plant, forklift charging bays and wastewater plant all sharing the same building envelope. The fish markets sit alongside this: Sydney Fish Market at Pyrmont (the largest in the Southern Hemisphere, undergoing an 836-million-dollar Blackwattle Bay redevelopment due for completion in the late 2020s), the Melbourne Wholesale Fish Market that relocated from Footscray to Epping, Brisbane Wholesale Fish Market at Hemmant, Adelaide Fish Market at Port Adelaide, Fremantle Fish Market in Western Australia, and the regional Townsville and Cairns Fish operations.

Foodservice wholesale runs in parallel. Bidfood Australia operates 25-plus distribution centres from a Brisbane head office. PFD Food Services runs 50-plus distribution centres from Melbourne. Holco in New South Wales and C+C Foodservice serve a national customer base. The dedicated cold-chain logistics operators — Linfox Logistics at Essendon Fields, Toll Logistics out of Melbourne, Lindsay Australia across the eastern seaboard, Ron Finemore Transport from Wagga Wagga — each move temperature-controlled freight through transit cross-docks that share the same HVAC challenges as the static wholesale market floors.

Six things make this combination harder than any individual application in isolation. First, the temperature span: a single building holds trading floor at 18-24 degrees Celsius next to 0-4 degree produce cool rooms, minus-1 degree fish cool rooms, minus-18 degree frozen rooms, plus-16 degree banana ripening rooms, plus-1-to-3 degree flower cool rooms, and an ammonia compressor room running its own internal HVAC. The total wall-and-duct surface area between zones is enormous and every interface is a potential condensation, thermal-bridge and biosecurity failure point. Second, the throughput: a market trading floor sees 200 to 800 forklift movements an hour during the trading peak, each one releasing diesel exhaust, particulate, latent moisture from washed-down floors, and pressure-pulse disturbance through any open duct grille. Third, the regulatory overlap: AS 1668.2 mechanical ventilation, AS 4254 ductwork construction, AS 1530.4 fire-rated duct, AS 1668.1 fire and smoke control, AS/NZS 1677 ammonia refrigerant, AS 5149 industrial refrigeration safety, AS 4326 wholesale and retail food premises HACCP, AS 4674 food premises construction, FSANZ standards 3.2.2 and 3.2.3, AS/NZS 60079 hazardous area classification for the ammonia compressor room, AS 1851 fire protection inspection, ASHRAE Standard 62.1 outdoor air, AS 3000 electrical and AS 3580 boundary emission monitoring all apply across one building. Miss any one and the certifier issues a non-conformance that delays handover. Fourth, the controlled-atmosphere rooms: banana ripening at 16-18 degrees with 50-100 ppm ethylene dosing, flower cool rooms with active ethylene exclusion below 50 parts per billion, mushroom cool rooms with carbon dioxide control below 1500 ppm. Each room is a small chemical process with the duct system as the reactor envelope. Fifth, the corrosive species: fish markets layer saline aerosol on top of hydrogen sulphide from gut waste, ammonia from refrigeration leakage, organic acids from fruit fermentation and chlorine bleach from end-of-shift sanitation. Galvanised steel ducts do not survive. Sixth, the public-facing weekend retail session: Paddy's Markets at Flemington, the Saturday public session at Brisbane Markets, the Adelaide Produce Markets Sunday session and the various smaller public sessions all subject the same building to a weekend public retail load, with food court tenancies, restaurant kitchens and pedestrian throughput layered on top of the wholesale ventilation design.

Get any one of those six wrong and the consequences are visible. A poorly sealed return duct on a banana ripening room can collapse a flower consignment in the neighbouring cool room. A galvanised return riser in a fish auction hall corrodes through in 18 months and condenses on the buyers below. An undersized ammonia compressor room emergency exhaust can release toxic ammonia at evacuation alarm concentration during a relief valve event. A forklift charging bay without ceiling-level hydrogen ventilation accumulates H2 within 4-6 hours of overnight charging and creates an explosive atmosphere. This guide walks through each zone, the standards that apply, the duct material specification, and the SBKJ machinery that produces the duct.

Australian operator landscape — who runs what and where it matters

Primary wholesale produce markets

Sydney Markets Limited is the company that operates Sydney Markets at Flemington, the largest wholesale fresh produce market in Australia and one of the ten largest in the world by floor area. The site covers 720 hectares, hosts 2500-plus tenants, runs the wholesale Flemington Markets trading floor from 03:00 to 11:00 most weekdays, and adds the public retail Paddy's Markets on Wednesdays, Fridays, Saturdays and Sundays. Sydney Markets Foundation supports industry research and education. The HVAC envelope across the site has been progressively upgraded since the 2010s, with newer cold room banks built to current AS 4254 Class B duct sealing and 316L stainless construction in the fish-handling and gut waste zones.

Melbourne Market Authority operates the Melbourne Market at Epping, which relocated from Footscray in 2015. The new 71-hectare site was built to a contemporary mechanical ventilation specification, with AS 1668.2 trading floor design, multi-temperature cold room banks, dedicated banana ripening and flower cool rooms, and ammonia compressor plant with AS 5149 compliance from day one. The Melbourne Wholesale Fish Market relocated to the same Epping site, sharing infrastructure with the produce market.

Brisbane Markets Limited operates Brisbane Markets at Rocklea, the primary wholesale fresh produce market in Queensland. The site combines wholesale trading with the Brisbane Wholesale Fish Market at Hemmant nearby, weekend public retail sessions, and dedicated tropical produce ripening rooms for North Queensland banana, mango, papaya and pineapple consignments arriving from Costa Group at Tully, Mackay Bananas and the various Far North Queensland growers.

Adelaide Produce Markets Limited operates the wholesale produce market at Pooraka, South Australia, serving wholesalers, growers and foodservice distributors across South Australia, Western Victoria and the Northern Territory. Perth Markets Limited operates Perth Markets at Canning Vale, the primary wholesale fresh produce market for Western Australia. The Hobart Showgrounds Market at Glenorchy operates at a smaller scale, serving Tasmanian wholesalers and the Hobart hospitality sector.

The regional wholesale markets in North Queensland Markets at Cairns, Mackay Wholesale Markets, Townsville Markets and Sunshine Coast Wholesale Markets each handle 50,000 to 250,000 tonnes of produce a year, with HVAC envelopes scaled accordingly — smaller trading floors, fewer cold room bays, but the same regulatory framework and the same fundamental material specifications.

Wholesale fish markets

Sydney Fish Market at Pyrmont is the largest fish market in the Southern Hemisphere and one of the largest seafood export markets in the ASEAN-Pacific region. The site combines a wholesale auction floor, public retail seafood stalls, the Sydney Seafood School as an adjunct cooking school, and back-of-house gut waste, ice plant and ammonia compressor rooms. The 836-million-dollar Blackwattle Bay redevelopment under construction at the time of writing is delivering a new flagship facility with contemporary HVAC throughout — multi-temperature cold rooms, dedicated 316L stainless gut waste extract trains, AS/NZS 60079 Zone 2 compliant ammonia compressor room ventilation, and full AS 4254 Class B sealing on the trading floor return ducts.

Melbourne Wholesale Fish Market relocated from Footscray to the Epping site sharing infrastructure with the Melbourne Market Authority. Brisbane Wholesale Fish Market at Hemmant serves Queensland wholesale buyers and the Brisbane hospitality sector. Adelaide Fish Market at Port Adelaide handles South Australian and Spencer Gulf seafood. Fremantle Fish Market in Western Australia serves Perth and the broader WA market. Regional Townsville and Cairns Fish handle local catch and aquaculture product from northern operators.

Banana ripeners and the controlled-atmosphere supply chain

Costa Group, listed on ASX as CGC, is the largest banana grower and ripener in Australia, with operations centred on Tully in Far North Queensland and ripening rooms at multiple wholesale market sites. Mackay Bananas operates a similar grower-ripener model in Central Queensland. Bananafarm Australia, LaManna Premier Group in Melbourne, Fresh Select at Werribee and Capilano Honey's fresh produce arm all run banana and tropical fruit ripening rooms with the controlled-atmosphere ethylene-dosing duct loops described later in this guide.

Foodservice wholesale and cold-chain logistics

Bidfood Australia (Brisbane head office, 25-plus distribution centres) and PFD Food Services (Melbourne head office, 50-plus distribution centres) are the two national foodservice wholesale operators. Holco serves New South Wales. C+C Foodservice operates across the eastern seaboard. The dedicated cold-chain logistics operators Linfox Logistics, Toll Logistics, Lindsay Australia and Ron Finemore Transport move temperature-controlled freight between the wholesale markets, distribution centres and end customers.

Industry bodies and policy framework

Fresh Markets Australia is the national body representing the central wholesale markets and member wholesalers. Sydney Markets Foundation supports industry research and educational outreach. Seafood Industry Australia (SIA) is the peak body for the Australian seafood industry. Horticulture Innovation Australia funds research and development across the fresh produce sector. The Australian Banana Growers Council represents banana growers and ripeners. Each of these bodies engages with the HVAC and cold chain regulatory framework and contributes to industry codes of practice.

Trading floor mechanical ventilation — the large-volume design

The trading floor of a major wholesale produce market is a large, mostly open volume — typically 5 to 15 hectares of covered floor area with ceilings 6 to 12 metres above slab, populated by stallholders' open-fronted boxes, pallet stacks, forklift transit lanes and a buyer concourse. The HVAC design has to satisfy AS 1668.2 mechanical ventilation, dilute forklift exhaust during the 03:00-to-11:00 trading peak, manage latent load from washed-down floors and washed produce, hold relative humidity in a band that does not damage chilled product passing across the floor, and provide acceptable thermal comfort for buyers, sellers and forklift operators across the year.

Air change rate and outdoor air component

The baseline mechanical ventilation rate is 5 to 6 air changes per hour calculated against the trading floor volume, which is the practical minimum under AS 1668.2 for a large industrial-grade ventilated space serving a mixed occupancy of food handlers, buyers and forklift operators. During the 03:00-to-07:00 trading peak, when forklift movements are at maximum and the trading floor is most densely occupied, the design rate is pushed to 8 to 10 ACH. This higher rate is typically delivered through variable-speed supply and exhaust fans interlocked to carbon monoxide monitoring per AS 1668.2 Appendix F — the supply increases automatically as CO concentration rises, and steps down through the late morning as forklift activity drops.

The outdoor air component sits at 10 L/s per person under AS 1668.2 Table 3.1 retail category for the public-facing public retail sessions, dropping to industrial-grade dilution ventilation for the wholesale weekday trade where the dominant occupants are food handlers rather than the general public. ASHRAE Standard 62.1 ventilation for acceptable indoor air quality applies as a parallel reference where international tenants or operators specify it. The Australian baseline is AS 1668.2; ASHRAE 62.1 is supplementary.

Humidity control on the trading floor

Trading floor humidity sits in a 40 to 60% RH band year-round. The lower bound limits static electricity discharge and respiratory comfort issues during dry winter weeks. The upper bound prevents condensation on cold-product cardboard cartons and on the underside of any cold supply duct routed across the trading floor. Sydney Markets Flemington and Brisbane Markets Rocklea, both in subtropical climates with summer outdoor humidity routinely above 80% RH, require active dehumidification across the wet season. Melbourne Market Authority and Adelaide Produce Markets in more temperate climates need dehumidification only during occasional humid summer weeks. Perth Markets in Western Australia and Hobart Showgrounds Market in Tasmania run mostly natural humidity control with supplementary dehumidification on demand.

Carbon monoxide monitoring and forklift exhaust dilution

Diesel-electric forklifts and diesel reach trucks remain common on Australian market trading floors despite progressive electrification. Diesel exhaust carries carbon monoxide at 200 to 1000 ppm at the tailpipe, diluted rapidly by trading floor mixing but capable of building to occupational exposure standard concentrations of 30 ppm 8-hour time-weighted average at the operator seat level if mechanical ventilation is undersized. Specify continuous CO monitoring per AS 1668.2 Appendix F with sensors at multiple locations across the trading floor, alarm at 30 ppm to step up supply and exhaust to the 8-10 ACH peak rate, and shutdown alarm at 60 ppm if mechanical ventilation cannot dilute. Safe Work Australia workplace exposure standard for CO is 30 ppm 8-hour TWA.

Duct material on the trading floor

Trading floor supply and return ducts are typically G90 galvanised, 0.7 to 1.2 mm gauge depending on size and pressure class, with TDF flange joints sealed to AS 4254 Class B or SMACNA Class A. The SBKJ SBAL-V auto duct production line in its standard galvanised configuration produces this trading floor specification at 16 m/min line speed across the 0.5-1.5 mm gauge range and 1500 mm coil width — sufficient throughput for a major market duct package to be fabricated on a single shift over a 4-to-6 week production window.

Large-diameter round supply trunks routed across the trading floor and serving multiple cold room branches use spiral galvanised duct produced on the SBKJ SBTF-1500C spiral tubeformer (1500 mm maximum diameter) or the larger SBTF-1602 or SBTF-2020 (1600 mm or 2000 mm maximum diameter) for the largest trunk runs. Spiral elbows are formed on the SBEM-1250 elbow former in tight 90-degree and 45-degree geometry, or on the SBLR-600 and SBLR-600A long-radius elbow formers (7.6 m/min line speed) where pressure drop minimisation matters on long horizontal mains.

Multi-temperature cold room banks — the produce, fish and frozen layer cake

The cold room bank is the heart of a wholesale market. A typical Australian central market holds 40 to 120 individual cold rooms across three to five temperature classes, with shared refrigeration plant (typically ammonia-based primary, occasionally CO2 transcritical or glycol secondary), shared corridors for forklift access, and a shared dock-and-loading apron. The HVAC duct package serves the in-room supply and return for each cold room, plus the corridor air movement, plus the dock seal and air curtain integration.

Produce cool rooms at 0-4 degrees Celsius

Produce cool rooms hold leafy vegetables, brassicas, root vegetables, salad greens, citrus, stone fruit and berries at 0 to 4 degrees Celsius. Relative humidity sits at 90 to 95% RH for high-respiration leafy product (lettuce, broccoli, spinach, asparagus), dropping to 85-90% for citrus and stone fruit, and to 90% for berries. Air change rate is 15 to 25 ACH for high-turnover trading rooms where product cycles through in 24-48 hours, dropping to 8 to 15 ACH for longer-cycle pallet storage rooms holding bulk consignments awaiting onward distribution.

Product zone velocity targets 0.3 to 0.5 m/s — sufficient mixing for thermal uniformity, low enough to avoid product dehydration. Supply duct material is G90 galvanised with closed-cell PIR insulation 50 to 75 mm thick and continuous foil vapour barrier. Return ducts where daily caustic washdown occurs step up to 304 stainless. Internal supply panel duct in 304 stainless with foam core is the preferred specification for the wettest zones, eliminating the separate insulation and vapour barrier trades.

Fish cool rooms at -1 degree Celsius

Fish cool rooms hold whole fish on ice or in ice-slurry chillers at -1 degree Celsius, the upper limit before unfrozen fish freezes. Relative humidity holds at 90-95% RH. Air change rate 15 to 20 ACH. The corrosive load is severe: saline aerosol from ice melt, fish blood drainage, hose-down water carrying organic acids and the residual ammonia from the refrigeration plant if any leakage exists. Duct material is 316L stainless minimum across the entire cool room envelope — supply ducts, return ducts, fan housings, dampers and access doors. Galvanised does not survive past 18-24 months in a fish cool room. The SBKJ SBAL-V in its 316L stainless variant produces this specification, with welded longitudinal seam tooling available as a factory option where AS 4254 Class C airtight sealing is specified.

Frozen storage at -18 degrees Celsius

Frozen storage rooms hold IQF (individually quick frozen) seafood, frozen vegetables, frozen ready meals and frozen meat at -18 to -25 degrees Celsius. ACH 8 to 12. Relative humidity 70 to 90%, product dependent. Insulation 100 to 150 mm closed-cell PIR with continuous vapour barrier. Material G90 galvanised with PIR jacket, or panel-insulated 304 stainless with foam core. Defrost cycle 2 to 4 times per day on hot-gas, 1 to 2 on electric.

Multi-temperature corridor and dock

The corridor between cold room banks runs at 8 to 12 degrees Celsius and 60-70% RH, sized to limit infiltration heat load on the adjacent cold rooms when doors open and to provide acceptable working conditions for forklift operators. Supply duct G90 galvanised with light PIR insulation. The dock at the building perimeter sits at 12 to 16 degrees Celsius (chilled dock standard) or 0 to 4 degrees Celsius (refrigerated dock at fish markets and some produce markets). Dock doors fitted with air-tight seals matched to truck profiles and air curtains at 1.5 to 2.5 m/s discharge velocity.

Banana ripening rooms — the controlled-atmosphere process duct

A banana ripening room is, in HVAC engineering terms, a sealed chemical reactor. The process specification:

• Temperature 16-18 degrees Celsius (some operators run 15-17 or 17-19 depending on cultivar and ripening protocol)
• Relative humidity 90-95% RH
• Ethylene C2H4 dosing 50-100 ppm into the room atmosphere
• Dosing duration 24 to 48 hours
• CO2 carbon dioxide scrubbing during ripening to hold CO2 below 5000 ppm
• Nitrogen N2 purge before personnel re-entry, reducing room ethylene to below 5 ppm and CO2 to below 1000 ppm

The duct system inside the ripening room is closed-loop recirculation — air leaves the room through a return duct, passes a process air handler (typically a coil for sensible cooling and humidity control, an ethylene dosing nozzle, a CO2 scrubber and a particulate filter), and returns through a supply duct to a header at ceiling level. The room itself is gas-tight with sealed wall panels, gas-tight isolation dampers at the supply and return interfaces to the corridor, and a separate N2 purge supply line routed from a liquid-nitrogen storage tank or a Pressure Swing Adsorption (PSA) nitrogen generator on site.

Material specification inside the ripening loop

Ethylene C2H4 is a small molecule (molar mass 28.05 g/mol) that diffuses readily through unsealed seams and porous gaskets. The duct system must be gas-tight to a higher standard than general HVAC. Material specification: 316L stainless steel throughout the recirculation loop, with welded longitudinal seams (not Pittsburgh lock, not TDF flange), continuous welded transverse joints, and EPDM or fluoroelastomer gaskets on any necessary access doors and inspection ports. The SBKJ SBAL-V in 316L stainless variant with welded longitudinal seam tooling produces this specification — the welded seam configuration adds 4 to 6 weeks to the standard lead time but is the only acceptable construction for a controlled-atmosphere ripening loop.

Ethylene monitoring and safety interlocks

Specify continuous ethylene monitoring at 0-200 ppm range at the return duct, oxygen monitoring at 19.5% low alarm to prevent asphyxiation during N2 purge, CO2 monitoring at 0-10000 ppm to verify CO2 scrubber performance, and door interlocks that prevent room access while ethylene is above 5 ppm or oxygen is below 19.5%. Safe Work Australia workplace exposure standard for CO2 is 5000 ppm 8-hour TWA and 30000 ppm STEL — the ripening protocol holds CO2 below the TWA during ripening, and the N2 purge before re-entry reduces CO2 below 1000 ppm to provide a safety margin.

Nitrogen purge supply line

The N2 purge supply runs from a liquid-nitrogen tank (typically 5000 to 20000 L capacity on a market site) through a vapouriser to a gas-tight supply duct to the ripening room ceiling header. The purge runs at 5 to 15 room volumes per hour for 30 to 60 minutes, reducing ethylene and CO2 to safe levels before door interlocks release. Material 316L stainless or aluminium — aluminium is acceptable for the N2 supply because it sees only inert gas, no oxygen until the door opens for personnel entry.

Operator-specific notes

Costa Group runs the largest network of Australian banana ripening rooms, with installations at the Tully Far North Queensland packing house and at multiple wholesale market sites including Sydney Markets, Melbourne Market and Brisbane Markets. LaManna Premier Group operates dedicated banana ripening at the Melbourne Market site. Mackay Bananas, Bananafarm Australia and the various smaller ripeners run similar specifications scaled to their volume. Fresh Select at Werribee runs ripening rooms as part of its broader produce pack-house operation. The Australian Banana Growers Council provides industry guidance on ripening protocols that informs the HVAC duct specification.

Flower cool rooms — the ethylene-exclusion specification

A flower cool room is the inverse of a banana ripening room. Cut flowers — roses, carnations, chrysanthemums, lilies, tulips, gerberas, and the Australian native flowers including waratah, banksia, kangaroo paw and Geraldton wax — are ethylene-sensitive. A single ppm of ethylene exposure can collapse a consignment of carnations in 12 hours, brown a rose head in 24 hours, or wilt a lily in 6 to 12 hours. The HVAC design specification:

• Temperature 1-3 degrees Celsius (some operators run 0-2 or 2-4 depending on flower type)
• Relative humidity 85-90% RH
• Active ethylene EXCLUSION — ethylene concentration in the room held below 50 ppb (parts per billion, not ppm)
• No shared return air with any zone storing ethylene-producing produce (bananas, avocados, mangos, stone fruit, tomatoes, melons)
• Carbon filter on the outdoor air make-up to absorb any trace ethylene from outside air
• Air change rate 8-15 ACH depending on product turnover and room volume

Physical isolation from ethylene-producing rooms

The flower cool room must be physically isolated from banana ripening rooms, climacteric-fruit cool rooms holding avocados or mangos, and any zone where ethylene-producing produce is handled. Specify dedicated supply and return air handlers, dedicated outdoor air make-up unit with activated carbon filter, dedicated return duct routing that does not pass through corridors shared with ripening rooms, and positive-pressure room operation at 15-25 Pa above adjacent corridors to drive any leakage outward rather than inward.

Material and construction

Duct material is G90 galvanised with closed-cell PIR insulation for general supply and return, stepping up to 304 stainless on the return duct where daily washdown is part of the cleaning regime. The carbon filter on the outdoor air intake is critical — specify a coconut-shell activated carbon bed sized for 10 g/h ethylene capture capacity, with a 6-month replacement schedule.

Monitoring

Specify continuous ethylene monitoring at the room return with detection sensitivity below 50 ppb — typically a chemiluminescence or PAS (photoacoustic spectroscopy) instrument calibrated quarterly. Alarm at 100 ppb triggers a corrective response (filter change, leak investigation), 500 ppb triggers product evacuation.

Citrus, stone fruit, berry and mushroom cool rooms

Citrus and stone fruit at 0-2 degrees Celsius

Citrus and stone fruit cool rooms hold oranges, mandarins, lemons, limes, grapefruit, peaches, nectarines, plums, apricots and cherries at 0 to 2 degrees Celsius with 90-95% relative humidity. Air change rate 15-25 ACH for high-turnover trading rooms, lower for longer-cycle storage. Material G90 galvanised supply with PIR insulation, 304 stainless return where washdown occurs. Note that stone fruit and citrus are mildly climacteric and produce ethylene at low rates — never share return air with flower cool rooms.

Berry cool rooms at 0-2 degrees Celsius

Berry cool rooms hold strawberries, blueberries, raspberries, blackberries and gooseberries at 0 to 2 degrees Celsius with 90% relative humidity. Air change rate 12-20 ACH. Berries are highly perishable (3-7 day shelf life from harvest), respond well to controlled-atmosphere with elevated CO2 (10-15% CO2 reduces respiration and extends shelf life), but most wholesale market berry rooms run conventional atmosphere because of throughput. Costa Group's berry operations and Driscoll's Australia push significant volumes through wholesale market berry rooms at Sydney, Melbourne and Brisbane.

Mushroom cool rooms at 1-4 degrees Celsius

Mushrooms continue to respire and produce CO2 even at refrigeration temperature. A mushroom cool room with poor ventilation accumulates CO2 to concentrations that drive flesh browning and reduce shelf life. Specify active CO2 management with continuous monitoring at 0-5000 ppm range, target operating CO2 below 1500 ppm in the storage envelope, and increase make-up air whenever CO2 rises above 2000 ppm. Temperature 1-4 degrees Celsius, RH 90-95%, ACH 12-18.

Ammonia compressor room — AS/NZS 60079 hazardous zone and AS/NZS 1677

The refrigeration plant serving a wholesale market cold room bank is typically ammonia-based — the dominant industrial refrigerant for large-scale cold storage, with excellent thermodynamic efficiency (COP 3.5-5.5), zero GWP, zero ODP, and a long track record of safe operation when designed and maintained under AS/NZS 1677 and AS 5149. The downside is toxicity (Safe Work Australia WES 25 ppm 8-hour TWA, 35 ppm STEL) and flammability (ASHRAE class B2L). The compressor room and the associated plant room ventilation duct package is the most safety-critical part of the market HVAC envelope.

Hazardous area classification

AS/NZS 60079.10.1 Hazardous areas — Classification of areas — Explosive gas atmospheres applies to any space where ammonia gas could foreseeably be released at concentration above 25% of the lower explosive limit (LEL). For ammonia, LEL is 15% by volume in air, so 25% LEL is 3.75% (37500 ppm) — well above the toxicity threshold (25 ppm WES) and the IDLH concentration (300 ppm). In practice the hazardous zone classification is driven by the toxicity envelope, not the explosive envelope.

The bulk of the compressor room volume is classified Zone 2 — an area in which an explosive atmosphere is not likely to occur in normal operation but, if it does occur, will persist for a short period only. The immediate envelope around relief valve discharge points, threaded ammonia connections and inspection access ports is classified Zone 1 — an area in which an explosive atmosphere is likely to occur in normal operation occasionally. All electrical equipment in Zone 1 must be EPL Gb (Equipment Protection Level Gb, suitable for Zone 1), Zone 2 equipment EPL Gc minimum. Fan motors, sensors, lighting and any control electronics must carry appropriate Ex-rating per AS/NZS 60079.0.

Emergency exhaust ventilation

AS/NZS 1677 and AS 5149 require emergency exhaust on ammonia detection at 25 ppm. The emergency exhaust rate is 30 ACH minimum, with the exhaust fan rated for continuous operation under the worst-case ammonia leak scenario — typically a relief valve discharge or a flange leak. Specify:

• Dedicated 316L stainless or epoxy-coated mild steel exhaust duct — galvanised forms a soluble zinc-ammine complex with wet ammonia within months and corrodes through within 12-18 months
• Welded longitudinal seam construction with continuous welded transverse joints
• Low-level extract pickup (for ammonia vapour pooling near floor after a refrigerant pool release) and high-level extract pickup (for gaseous ammonia rising buoyantly — ammonia is lighter than air at 0.59 specific gravity)
• Ex-rated EPL Gb fan motor in Zone 1 areas, EPL Gc in Zone 2
• Discharge to atmosphere at least 3 m above any opening, away from prevailing wind to nearby occupied buildings
• AS/NZS 60079.14 compliant electrical installation throughout

Ammonia detection and alarm interlocks

Specify continuous electrochemical ammonia detection with sensors at multiple locations — near each compressor, at the room high level, at the room low level near the floor, near the relief valve discharge point and at the corridor interface. Alarm thresholds:

• 25 ppm (8-hour TWA WES) — level 1 alarm, step up emergency exhaust to 30 ACH, notify control room
• 35 ppm (STEL WES) — level 2 alarm, evacuation alarm, automatic compressor shutdown
• 300 ppm (IDLH) — full plant shutdown, fire brigade notification

Eye-wash and emergency shower

AS/NZS 1677 requires eye-wash and emergency shower stations within 10 metres of any ammonia connection point, accessible without passing through any door, with potable water supply rated for 15-minute continuous flow per ANSI Z358.1 (referenced by AS/NZS 1677). These stations are part of the room infrastructure, not the HVAC duct package, but the duct routing must not block access to them.

Fish gut waste room — H2S and organic odour extract

A wholesale fish market generates a continuous stream of gut waste, scale, blood, ice melt and processing offal that is collected in a dedicated waste room before transfer to a rendering plant or organic waste contractor. Within hours of collection, the waste begins anaerobic decomposition and releases hydrogen sulphide H2S, dimethyl sulphide, dimethyl disulphide and a complex of organic acids and amines. Concentrations of H2S build rapidly to above the odour threshold (0.0047 ppm) and approach the Safe Work Australia WES (10 ppm 8-hour TWA, 15 ppm STEL) within hours of warm-weather operation.

Captured-source extract

Specify captured-source extract at the waste collection point, the bin transfer station and the wash-down area. Capture velocity 0.5 to 1.0 m/s at the source per ACGIH Industrial Ventilation Manual. Duct material 316L stainless steel throughout — H2S forms iron sulphide on mild steel and aggressive pitting on 304 stainless within months. The SBKJ SBAL-V in its 316L stainless variant produces this specification with welded longitudinal seam tooling for the air-tight extract train.

Odour treatment

The extracted airstream is treated before atmosphere release. Three treatment options apply:

• Activated carbon scrubber — effective for organic odour, requires regular media replacement (3-6 month interval), capital cost moderate, OPEX dominated by media cost
• Biofilter — bacterial degradation on a packed bed of organic media (woodchip, peat, coconut fibre), effective for sustained low-concentration streams, large footprint, low OPEX once established
• Wet caustic scrubber — sodium hydroxide solution absorbs H2S and organic acids, high efficiency on peak loads, requires caustic management infrastructure, suited to large markets with continuous high-volume waste streams

Sydney Fish Market Pyrmont historically operates a combination of biofilter and wet caustic scrubber on its waste extract. The new Blackwattle Bay facility under construction includes a contemporary multi-stage odour treatment train. Brisbane Wholesale Fish Market at Hemmant and Fremantle Fish Market run dedicated biofilter installations. Adelaide Fish Market at Port Adelaide and the regional Townsville and Cairns Fish operations run activated carbon scrubbers.

Boundary emissions monitoring

AS 3580 Methods for sampling and analysis of ambient air applies to boundary monitoring of H2S and other odorous compounds at the property line. Specify continuous H2S monitoring at the boundary with alarm at 1 ppm action level and integration with the facility environmental management plan. State EPA approval (NSW EPA, EPA Victoria, Queensland Department of Environment, Western Australian DWER) governs the licence conditions for fish market operations and the boundary emission limits.

Forklift battery charging station — hydrogen and lithium-ion

Wholesale market forklift fleets are progressively shifting from internal combustion engines to electric — flooded lead-acid in the older fleets, lithium-iron-phosphate LFP in newer installations. The charging bay HVAC design differs sharply between the two technologies.

Flooded lead-acid charging

Flooded lead-acid batteries release hydrogen H2 gas at the end of the charge cycle, typically above 80% state of charge during the equalisation phase. AS/NZS 5139 Electrical installations — Safety of battery systems for use with power conversion equipment and IEC 62485-3 Safety requirements for secondary batteries and battery installations — Part 3: Traction batteries specify the dilution ventilation calculation:

Q = 0.05 × n × I × Cn / 1000, where Q is the required ventilation airflow in cubic metres per hour, n is the number of cells in series, I is the gassing current per cell in amps, and Cn is the rated battery capacity in ampere-hours.

In practice, a charging bay with 6 to 10 lead-acid forklift chargers operating concurrently requires 4 to 6 air changes per hour minimum, rising to 10 to 15 ACH where 20-plus chargers run concurrently. Specify:

• Spark-resistant aluminium or 316L stainless supply ductwork at ceiling level — hydrogen rises and accumulates at the highest point in the space, so the dilution airflow has to wash through that high-level volume
• Galvanised acceptable on lower-level return ducts
• Continuous hydrogen detection at ceiling level with alarm at 1% of LEL (LEL is 4% by volume, so 1% LEL is 0.04% or 400 ppm) and shutdown at 25% LEL (1% H2 by volume)
• Charger interlock that disables charging on alarm and restores only after H2 falls below 0.5% LEL
• No spark-producing equipment within the charging bay envelope — lighting, switchgear and any electrical work to AS/NZS 60079.14 standards for Zone 2 hazardous area

Lithium-iron-phosphate (LFP) charging

LFP charging releases negligible hydrogen and presents a different risk profile — thermal runaway propagation in the event of cell failure, with potential for fire spread between adjacent battery packs. AS/NZS 5139 and NFPA 855 Standard for the Installation of Stationary Energy Storage Systems govern the separation distances, the thermal runaway venting, and the fire suppression requirements. The HVAC implications:

• Dedicated charging bay separated from other operations by fire-rated partition (typically 2-hour rating per AS 1530.4)
• Smoke extract duct sized for thermal runaway venting per NFPA 855 — this is significant volume, typically 10-15 ACH continuous with step-up to 30 ACH on smoke detection
• Duct material 316L stainless or 304 stainless to tolerate the corrosive vent gases (electrolyte vapour, HF hydrogen fluoride from LiPF6 decomposition)
• Integration with facility fire alarm system per AS 1670 and AS 1851 inspection regime

Electric tug, pallet jack and reach truck depot

The depot where electric tugs, pallet jacks and reach trucks park overnight is a less critical zone than the formal battery charging bay because the chargers in these zones are typically lower-capacity opportunity chargers running below the gassing threshold of the battery. Standard mechanical ventilation under AS 1668.2 at 5-6 ACH is adequate, with H2 detection at ceiling level as a safety overlay.

Loading dock seals and air curtains

The loading dock at a wholesale market is the interface between conditioned indoor air and outdoor ambient. Every dock door cycle — and a busy market sees 200 to 500 dock door cycles a shift — admits an air parcel matched to outdoor temperature and humidity. The energy load and the condensation risk on the cold room return ducts running across the dock both depend on managing this exchange.

Dock door seals

Specify dock door seals matched to the truck profile: rubber compression seal for refrigerated panel trucks, foam shrouds for reefer containers, inflatable seals for full-size refrigerated trailers. Sydney Markets Flemington and Brisbane Markets Rocklea, with their high refrigerated freight volumes, use inflatable seals on the high-frequency cold-chain docks. Adelaide Produce Markets and Perth Markets, with lower volumes, often use foam shrouds. Sydney Fish Market Pyrmont uses inflatable seals throughout because the chilled fish dock cycles continuously.

Air curtains

An air curtain at 1.5 to 2.5 m/s discharge velocity at the dock door provides supplementary infiltration control during the seconds between truck arrival and seal engagement. Specify the air curtain mounted at door head height with horizontal discharge across the door opening, sized for the door width (typical 4-6 metres on a wholesale dock), and interlocked with the dock door so the curtain runs only while the door is open. Curtain heat recovery from the adjacent cold room return air can offset roughly 30-50% of the dock heating load in temperate climates.

Energy recovery integration

Modern market designs recover the return air from the cold room banks and use it to temper the loading dock space. The cold room return is at 8 to 12 degrees Celsius (chilled cool room return) or 0 to 4 (refrigerated dock return), well below the dock setpoint of 12 to 16 degrees Celsius. A simple cross-flow heat exchanger or a glycol run-around coil transfers 60-80% of the available sensible heat from the supply outdoor air to the cold room return, reducing the net heating load on the dock by an order of magnitude.

Buyer and seller offices — commercial HVAC inside an industrial envelope

The trading floor mezzanine at every major Australian wholesale produce market hosts a layer of buyer and seller offices — typically 100 to 300 small offices for individual wholesaler businesses, plus management offices for the market operator (Sydney Markets Limited, Melbourne Market Authority and so on). These offices are conventional commercial HVAC at 22-24 degrees Celsius setpoint, 50% RH, V_p 10 L/s/person under AS 1668.2 Table 3.1 office category, with the added complexity that the office HVAC discharges adjacent to a noisy industrial trading floor.

Acoustic attenuation

The trading floor generates 75 to 90 dB(A) ambient noise during peak trading from forklifts, voice traffic, refrigeration plant and dock activity. The office HVAC supply duct breakthrough must be controlled to AS/NZS 2107 internal noise levels — typically 40-45 dB(A) NR (Noise Rating) in offices. Specify acoustic attenuators inline on the supply branch entering each office cluster, with insertion loss matched to the trading floor noise spectrum. See our acoustic duct lining and attenuator guide for sizing tables.

Fire-rated duct rises

Office ducts that rise through more than one fire compartment require AS 1530.4 fire-rated enclosure, typically 2-hour rating, with AS 1851 inspectable fire dampers at each compartment penetration. Material galvanised G275 or stainless 304 wrapped in mineral wool fire jacket and outer steel skin.

Auction halls — the Sydney Fish Market case

Sydney Fish Market at Pyrmont operates the largest wholesale fish auction in the Southern Hemisphere, with 200 to 600 buyers seated around the auction clock during peak trading. The auction hall is a large open volume with tiered seating, the Dutch-clock auction display, the fish display deck where each lot is presented for inspection, and the back-of-house transfer to the dispatch deck. The HVAC design has to satisfy several competing requirements:

• V_p 10 L/s/person under AS 1668.2 Table 3.1 for the seated buyer occupancy
• 5-6 ACH bulk ventilation for the displayed fish and the early-morning forklift loading of fish lots onto the display deck
• Humidity at 60-70% RH — high enough to limit fish dehydration during the 30-90 minute display window, low enough to avoid condensation on the auction clock display and the public-facing viewing gallery glazing
• Temperature 14-18 degrees Celsius — cool enough to preserve fish quality, warm enough that seated buyers are not chilled during the 3-4 hour auction

Duct material for the auction hall

The auction hall return air carries saline aerosol from the displayed fish and ice. Specify 316L stainless steel return ducts and 304 stainless supply ducts. The auction floor seating and the buyer concourse can run on G90 galvanised supply because the supply air is conditioned and dehumidified before entering the room. The display deck supply, which discharges air directly onto the displayed fish for both temperature control and a slight surface drying effect that improves fish appearance, runs on 304 stainless because the supply duct sees recirculation back into the saline-laden return.

Public viewing gallery

The Sydney Seafood School is an adjunct of Sydney Fish Market that operates as a public cooking school and public viewing gallery overlooking the auction floor. The viewing gallery has its own HVAC at general retail rates (V_p 10 L/s/person AS 1668.2 retail category) with positive-pressure operation to keep the auction floor air separated from the public space. Glazing between the gallery and the auction floor is double-glazed with thermal break to prevent condensation during cold auction operation.

Public retail food court and restaurant tenancies

Most major Australian wholesale produce markets host a public retail session on weekends with food court tenancies — Paddy's Markets at Flemington on Wednesdays, Fridays, Saturdays and Sundays, the Saturday and Sunday public sessions at Brisbane Markets, the Sunday session at Adelaide Produce Markets. The food court typically hosts Asian wok stations, grill and burger lines, coffee and bakery tenancies, juice bars and prepared-meal vendors. Each tenancy generates its own grease and steam load.

Grease duct construction

NFPA 96 Standard for Ventilation Control and Fire Protection of Commercial Cooking Operations governs grease duct construction, referenced through AS 1851 fire protection inspection and the National Construction Code (NCC) Volume One in Australian practice. Grease ducts are:

• 16-gauge welded liquid-tight construction (1.5 mm minimum thickness)
• Material 316L stainless steel for high-temperature wok and char-grill exhaust, 304 stainless for general grill and fryer exhaust
• Full continuous welds on all longitudinal and transverse seams — no Pittsburgh lock, no TDF flange, no riveted joints
• Slope to drain at 50 mm per metre toward a grease residue collection sump
• AS 1530.4 fire-rated enclosure where the duct rises through more than one floor or passes through a fire compartment — typically 2-hour rating
• Integrated wet chemical or water-mist suppression per AS 1851 and the relevant tenancy fire safety design

SBKJ machinery for food court grease ducts

The SBAL-V auto duct line in its 316L stainless variant with welded longitudinal seam tooling produces NFPA 96-compliant grease duct on a single production line. Output is full-length straight sections that the on-site fabricator joins with continuous welded transverse joints. For the spiral round grease duct rising through tenancy stacks, the SBTF-1500C spiral tubeformer in 316L stainless produces welded-seam spiral with the slope-to-drain pitch built into the install detail.

Public retail Sunday market HVAC

The public retail session itself runs under AS 1668.2 Table 3.1 retail category at V_p 10 L/s/person, supplemented by the trading floor bulk ventilation. Carbon monoxide monitoring per AS 1668.2 Appendix F continues to apply where any vehicle access remains during public hours — some markets restrict forklift movement during the public retail session to limit CO loading. ASHRAE Standard 62.1 ventilation for acceptable indoor air quality is an alternative reference where international tenants apply it.

Wastewater grease trap and tallow separator exhaust

Wastewater plant at a wholesale market handles fish blood, gut waste rinse, vegetable wash water, dock wash-down, and the food court grease trap effluent. The grease trap and tallow separator generate H2S, methane CH4 and reduced sulphur compounds from anaerobic decomposition. Specify:

• 316L stainless extract duct from the grease trap headspace
• Intrinsically safe motor where methane concentration above 25% LEL is foreseeable (LEL methane is 5% by volume, so 25% LEL is 1.25%)
• Integrated activated carbon scrubber or biofilter before atmosphere release
• Routing high above any pedestrian or public space
• AS 3580 boundary monitoring for community amenity compliance
• Continuous H2S monitoring at the extract intake with alarm at 1 ppm

Standards stack — what the certifier actually checks at handover

AS 1668.2 mechanical ventilation

AS 1668.2 The use of ventilation and air conditioning in buildings — Mechanical ventilation in buildings is the primary mechanical ventilation standard in Australia. It governs minimum outdoor air rates, exhaust rates, dilution ventilation for industrial-grade spaces, contaminant-control ventilation for hazardous environments, and the calculation procedures for sizing supply and exhaust fans. Every zone in a wholesale market is sized against AS 1668.2 first, with ASHRAE 62.1 as a supplementary reference where international operators apply it.

AS 4254 ductwork construction

AS 4254 Ductwork for air-handling systems in buildings governs the construction of HVAC ductwork in Australia. Parts 1 (flexible duct) and 2 (rigid duct) cover the material specifications, the seam and joint construction, the sealing classes (A, B and C), the pressure classes and the testing procedures. SBKJ's machinery is configured to produce AS 4254-compliant duct as standard, with Pittsburgh lock seam and TDF flange tooling for general applications and welded longitudinal seam tooling for controlled-atmosphere, hazardous-zone and grease duct applications.

AS 1530.4 fire-rated duct

AS 1530.4 Methods for fire tests on building materials, components and structures governs the fire resistance level (FRL) of building elements including HVAC ductwork. Fire-rated ducts at wholesale markets apply to grease duct rises through multiple floors, smoke extract ducts in atria, and any duct passing through a fire compartment boundary. The typical specification is a 2-hour FRL achieved with mineral wool blanket wrap or a proprietary fire-rated panel system around a steel inner duct.

AS 1668.1 fire and smoke control

AS 1668.1 The use of ventilation and air conditioning in buildings — Fire and smoke control in buildings governs the HVAC integration with fire and smoke control systems — smoke extract, smoke spill, stair pressurisation, and the interlocks between mechanical ventilation and the building fire alarm. Wholesale markets with large trading floor volumes typically require smoke extract systems sized to AS 1668.1 to clear the floor in the event of a fire on a tenant stall.

ASHRAE Applications and AS 5149

ASHRAE Applications Chapter 22 Refrigerated Facilities and Chapter 25 Food Refrigerated Facilities provide the supplementary engineering reference for cold storage facilities at wholesale markets. AS 5149 Refrigerating systems and heat pumps — Safety and environmental requirements governs industrial refrigeration plant safety including ammonia systems. AS/NZS 1677 Refrigerating systems specifies safety classifications and machinery room requirements specifically for ammonia.

AS 4326, AS 4674, FSANZ 3.2.2 and 3.2.3

AS 4326 The storage and handling of food in wholesale and retail premises (commonly known by the HACCP framework) and AS 4674 Design, construction and fit-out of food premises govern the food safety construction requirements at wholesale market food handling zones. FSANZ (Food Standards Australia New Zealand) standards 3.2.2 Food Safety Practices and General Requirements and 3.2.3 Food Premises and Equipment apply to all food handling areas. HACCP and ISO 22000 audit schemes overlay these standards for export-facing operations.

AS 1851 fire protection

AS 1851 Routine service of fire protection systems and equipment governs the annual inspection and maintenance of fire dampers, smoke dampers, smoke extract fans, grease duct suppression systems and the HVAC-integrated fire and life safety systems. Wholesale markets schedule AS 1851 inspections annually with documented inspection records held by the building owner.

NHMRC and indoor air quality

The National Health and Medical Research Council (NHMRC) publishes guidance on indoor air quality that supplements the AS 1668.2 mechanical ventilation framework. The guidance covers particulate, microbial and chemical contaminants and the ventilation strategies that limit each. Wholesale markets that host public retail sessions reference NHMRC guidance in their indoor air quality management plans.

AS 3000 electrical and AS/NZS 60079

AS 3000 Electrical installations (the Wiring Rules) governs electrical installation throughout the facility. AS/NZS 60079 Explosive atmospheres governs electrical installation in hazardous areas — the ammonia compressor room, the forklift lead-acid charging bay, the wastewater plant methane zone, and any other space where flammable gas accumulation is foreseeable. Hazardous area classification drawings are part of the design documentation and the as-built drawing set.

AS 3580 boundary emissions

AS 3580 Methods for sampling and analysis of ambient air governs the boundary emission monitoring at the property line. Fish markets in particular operate under EPA licence conditions that specify boundary H2S limits, total reduced sulphur limits and odour intensity limits.

Duct material zoning summary across the facility

The single most important specification decision is duct material per zone. The summary across a typical major Australian wholesale market:

• Trading floor general supply and return: G90 galvanised, 0.7-1.2 mm gauge, AS 4254 Class B sealing, TDF flange joints — SBAL-V galvanised variant
• Produce cool rooms 0-4 degrees Celsius supply: G90 galvanised with closed-cell PIR insulation 50-75 mm and continuous foil vapour barrier — SBAL-V galvanised variant
• Produce cool rooms return (daily washdown): 304 stainless, AS 4254 Class B sealing — SBAL-V 304 variant
• Fish cool rooms -1 degree Celsius, supply and return: 316L stainless throughout, welded longitudinal seam, AS 4254 Class C airtight sealing — SBAL-V 316L variant with welded seam tooling
• Frozen storage -18 degrees Celsius: G90 galvanised with 100-150 mm PIR insulation or panel-insulated 304 stainless — SBAL-V galvanised or 304 variant
• Banana ripening room recirculation: 316L stainless, welded longitudinal seam, gas-tight construction — SBAL-V 316L variant with welded seam tooling
• Flower cool room supply and return: G90 galvanised supply with PIR, 304 stainless return, dedicated air handler — SBAL-V galvanised and 304 variants
• Citrus, stone fruit, berry, mushroom cool rooms: G90 galvanised supply with PIR, 304 stainless return — SBAL-V galvanised and 304 variants
• Ammonia compressor room emergency exhaust: 316L stainless or epoxy-coated mild steel, welded longitudinal seam, AS/NZS 60079.14 compliant electrical installation — SBAL-V 316L variant with welded seam tooling
• Fish gut waste room extract: 316L stainless throughout, welded longitudinal seam, biofilter or scrubber discharge — SBAL-V 316L variant with welded seam tooling
• Forklift lead-acid charging bay supply (ceiling level): Spark-resistant aluminium or 316L stainless — SBTF spiral tubeformer in aluminium or SBAL-V 316L variant
• Forklift lead-acid charging bay return (low level): G90 galvanised — SBAL-V galvanised variant
• Forklift LFP charging bay: 316L or 304 stainless with thermal runaway vent capacity — SBAL-V stainless variant
• Loading dock supply and return: G90 galvanised, 304 stainless on the refrigerated dock interface — SBAL-V galvanised and 304 variants
• Buyer and seller office HVAC: G90 galvanised with acoustic attenuator inline — SBAL-V galvanised variant, SBLR long-radius elbow formers for low-pressure-drop runs
• Auction hall supply, return and display deck: G90 galvanised supply, 304 stainless display, 316L stainless return — SBAL-V galvanised, 304 and 316L variants
• Public retail food court tenancy grease duct: 316L stainless 16-gauge welded liquid-tight, AS 1530.4 fire-rated enclosure — SBAL-V 316L variant with welded seam tooling, SBTF spiral 316L
• Wastewater grease trap extract: 316L stainless with intrinsically safe motor where methane > 25% LEL — SBAL-V 316L variant

SBKJ machinery configuration for a wholesale market duct package

A complete duct package for a major Australian wholesale market — trading floor, cold room banks, ripening rooms, flower cool, ammonia plant, fish gut waste, forklift charging, food court, offices and dock — is fabricated on a portfolio of SBKJ production machinery configured to handle the material mix and the seam-construction variation required across the zones. The standard configuration:

SBAL-V auto duct production line

The SBAL-V is SBKJ's flagship auto duct production line, configured at 16 m/min line speed, 87 kW total installed power, 0.5 to 1.5 mm gauge range and 1500 mm coil width. The line produces rectangular duct from coil through decoiling, levelling, notching, Pittsburgh lock seam roll forming (or welded longitudinal seam in the welded variant), TDF flange (or angle flange) formation and length cut-off. The SBAL-V is the production workhorse for trading floor supply and return ducts, produce cool room supply, frozen storage supply, flower cool room supply and return, and the bulk of the trading-floor-side rectangular duct package. Configured in G90 galvanised variant for the general trading floor work, 304 stainless for the wet-zone return ducts and food court tenancy ducts, and 316L stainless for the fish, ammonia, banana ripening and gut waste extract zones. Read our SBAL-V product page and the SBAL-V vs SBAL-III comparison for full specifications.

SBAL-III auto duct line (mid-range)

The SBAL-III is the mid-range auto duct line at 14 m/min and 15.7 kW installed power, configured for smaller-throughput fabricators or for backup production capacity on a major project. The SBAL-III handles the same Pittsburgh lock and TDF flange formation as the SBAL-V at lower throughput, suitable for the regional market projects at Hobart, Mackay, Townsville and Cairns where the duct package size does not justify the SBAL-V production rate.

SBAL-II auto duct line (entry)

The SBAL-II is the entry-level auto duct line at 18 m/min line speed and 5.5 kW installed power, suitable for the smallest market upgrades or for fabricators specialising in office and food court ductwork on a small project scale.

SBTF spiral tubeformer (round duct)

The SBTF spiral tubeformer is the SBKJ standard for round duct production. The SBTF-1500C handles up to 1500 mm diameter, the SBTF-1602 up to 1600 mm and the SBTF-2020 up to 2000 mm. Round duct trunks across a wholesale market trading floor typically sit in the 800 to 1500 mm range, so the SBTF-1500C is the standard configuration. Material galvanised, 304 stainless and 316L stainless on the same tooling base with a tooling change.

SBFB-1500 spiral flange and beading line

The SBFB-1500 produces spiral duct with integrated flange and beading at 7.5 kW and 1.20 m/min line speed. Used for the cold room return riser ducts where the spiral duct rises from floor level to ceiling level through the cool room corridor, with flanged joints at each level for accessibility and for fire-rated enclosure compliance where required.

SBEM-1250 elbow former

The SBEM-1250 forms spiral elbows up to 1250 mm diameter in 30-degree, 45-degree and 90-degree sweep geometry. Used for the elbow connections at the cold room branch take-offs, the ripening room recirculation loop and the gut waste extract train.

SBSF-1525 shearing line

The SBSF-1525 is a plate shearing line at 2.5 kW, used for plate work on transitions, plenums and custom duct fittings that fall outside the auto-line standard geometry.

SBLR-600 and SBLR-600A long-radius elbow former

The SBLR-600 and SBLR-600A long-radius elbow formers produce sweep-style elbows with low pressure drop, operating at 7.6 m/min line speed. Used for the trading floor main supply trunks where pressure drop minimisation matters on long horizontal mains, and for the spiral elbows on the high-flow cool room return paths.

SBHF coil feeder

The SBHF coil feeder line provides high-throughput coil decoiling and feed to the SBAL-V or SBTF lines on multi-shift production runs. A major wholesale market duct package typically runs 50 to 200 tonnes of coil through the production lines over a 6 to 10 week fabrication window, with SBHF feed providing continuous material supply without interruption.

SBPC1500 plasma cutting

The SBPC1500 plasma cutting line cuts custom plate components, transition geometry and custom duct fittings up to 1500 mm working width. Used for the project-specific transitions and the custom plenum geometry at the ammonia compressor room, the banana ripening room and the fish auction hall.

Lead time and commissioning timeline

Major market duct package — 16 to 22 weeks

A full duct package for a new wholesale fresh produce market or fish market typically runs 16 to 22 weeks from approved drawings to final on-site delivery if fabricated on Australian SBKJ-supplied production lines in a single mixed-material specification. Lead time extends to 22 to 28 weeks if material is mixed galvanised and 316L stainless with welded longitudinal seam construction in the fish and ripening zones. The Sydney Fish Market 836-million-dollar Blackwattle Bay redevelopment is on a 24-month design and commissioning timeline, of which the HVAC duct package consumes roughly 14 to 18 months from concept to handover.

Regional market upgrade — 12 to 16 weeks

For the smaller central market upgrades — Adelaide Produce Markets, Perth Markets, Hobart Showgrounds Market expansion, the regional North Queensland and Sunshine Coast markets — a 12 to 16 week duct package window is realistic provided drawings are stable and material is locked early.

Cold room bank retrofit — 8 to 14 weeks

An incremental cold room bank retrofit on an existing market site (typically 10-30 new or refurbished cool rooms, with the ammonia plant and trading floor envelope unchanged) runs 8 to 14 weeks for the duct package depending on the number of stainless variants required.

Commissioning sequence

The commissioning sequence for a wholesale market HVAC package:

• Week 1-2: Installation walk-down, as-built versus drawing verification, mill certificate collation, AS 4254 leakage testing on completed duct sections
• Week 3-4: Air balance to AS 1668.2 outdoor air rates and ACH targets, dehumidification system commissioning to 40-60% RH trading floor band
• Week 5-6: Cold room bank commissioning — airflow distribution, ACH per cool room, product zone velocity, pressurisation cascade
• Week 7: Controlled-atmosphere room commissioning — banana ripening loop with ethylene dosing test, flower cool room ethylene exclusion verification, mushroom CO2 control verification
• Week 8-9: Hazardous-zone commissioning — ammonia compressor room emergency exhaust at 30 ACH on simulated ammonia detection, forklift lead-acid charging bay hydrogen ventilation verification, AS/NZS 60079 electrical installation inspection
• Week 10: Fire and life safety commissioning — AS 1851 fire damper inspection, AS 1668.1 smoke extract verification, grease duct suppression test, fire alarm integration
• Week 11-12: Documentation compilation — commissioning binder build, deviation investigation, regulatory submission to the certifier, AS 1851 baseline inspection records, HACCP and AS 4326 verification

Energy and operational economics

A major wholesale market HVAC system consumes significant electrical energy — typically 8 to 25 GWh per year depending on size, climate and product mix. The dominant load components are the trading floor supply and exhaust fans (often running 16-20 hours a day during operational weeks), the cold room bank refrigeration plant, the banana ripening room recirculation fans, and the dock door heating in winter. Energy efficiency interventions that materially reduce OPEX:

• Variable frequency drives on every supply and exhaust fan above 5 kW, interlocked to CO monitoring, occupancy and ACH demand — typically saves 25-40% on fan energy
• Demand-controlled ventilation per AS 1668.2 Appendix F — CO sensors on the trading floor step ventilation up during peak forklift activity, down during cleaning and night shutdown
• Heat recovery from cold room return to dock heating — 60-80% sensible heat transfer offsets the dock heating load in temperate climates
• Dehumidification setpoint control — 40-60% RH band rather than fixed setpoint allows the system to drift up in winter (less reheat energy) and down in summer (less dehumidification energy)
• Ammonia plant heat recovery from the compressor discharge to hot water for cleaning and dock heating — saves 20-30% on the cleaning hot water load

The NCC Section J energy efficiency provisions and the National Australian Built Environment Rating System (NABERS) for shopping centres provide the regulatory framework for energy efficiency in market facilities. See our NCC Section J reference for the energy efficiency duct specifications.

FAQ

What air change rate should the trading floor of a wholesale fresh produce market run at?

Trading floors at Sydney Markets Flemington, Melbourne Market Authority Epping and Brisbane Markets Rocklea typically operate between 5 and 6 air changes per hour as a minimum mechanical ventilation rate under AS 1668.2, with the practical design figure pushed higher to 8-10 ACH during early-morning trading peaks when forklift CO and diesel reach-truck movements load the space. Outdoor air component sits at 10 L/s per person under AS 1668.2 Table 3.1 for the public-facing retail Sunday session, dropping to industrial-grade dilution ventilation for the wholesale weekday trade. The dominant load is sensible heat from buyers and diesel-electric forklifts plus latent load from washed produce — set dehumidification to maintain 40-60% relative humidity year-round to limit condensation on chilled product and on the underside of any cold supply duct routed across the trading floor.

Why does galvanised G275 not last in a wholesale fish market and what should specifiers use instead?

Wholesale fish markets like Sydney Fish Market Pyrmont, Brisbane Wholesale Fish Market Hemmant and the Melbourne Wholesale Fish Market at Epping run continuously in saline aerosol from ice melt, fish blood drainage, hose-down water and Pacific salt air. Galvanised G275 (Z275 in metric, 275 g per square metre zinc) corrodes through the zinc layer within 18 to 36 months in trading floor return ducts, faster in fish gut waste rooms where hydrogen sulphide concentrations build above 5 ppm. Default to 316L stainless steel for all return ducts on the auction floor, the gut waste extract train, the ice plant room and any duct within 5 m of the seawater wash bay. Use 304 stainless for general supply ducts and packaging hall transfer ducts where chloride exposure is only intermittent. Galvanised G275 is acceptable only in remote mechanical plant rooms and rooftop AHU enclosures where the duct sees no direct salt water and no fish handling. SBKJ runs 316L on every fish-market-spec SBAL-V auto duct line order destined for Sydney, Brisbane, Adelaide, Fremantle or Townsville. See our galvanised vs stainless steel duct guide for full material selection rules.

How is ethylene controlled inside a banana ripening room and what is the duct specification?

Australian banana ripening rooms run by Costa Group at Tully, LaManna Premier in Melbourne and Mackay Bananas in Queensland use sealed pressurised rooms at 16-18 degrees Celsius and 90-95% relative humidity with ethylene C2H4 dosed at 50-100 ppm for 24 to 48 hours, followed by a forced N2 nitrogen purge before personnel re-entry. The duct specification is closed-loop recirculation through 316L stainless with welded longitudinal seams to eliminate ethylene leakage to adjacent rooms, a dedicated dosing nozzle on the supply manifold, dual gas-tight isolation dampers at room entry and exit, and integrated CO2 carbon dioxide scrubbing to keep CO2 below 5000 ppm during the ripening window. The N2 purge supply line is a separate stainless or aluminium duct routed from a liquid-nitrogen tank or PSA nitrogen generator. Never share return air between a banana ripening room and a flower cool room — flowers are ethylene-sensitive and a single ppm of ethylene can collapse a consignment of carnations or roses within 12 hours.

What hazardous zone classification applies to an ammonia compressor room at a wholesale market cold room bank?

Ammonia compressor rooms serving market cold room banks are classified under AS/NZS 60079.10.1 as Zone 2 hazardous areas for the bulk of the room volume, with localised Zone 1 around relief valve discharge points and the immediate envelope of any threaded ammonia connection. Mechanical ventilation under AS/NZS 1677 and AS 5149 requires emergency exhaust at 30 air changes per hour minimum on ammonia detection above 25 ppm, dedicated 316L stainless or epoxy-coated mild steel duct because galvanised forms a soluble zinc-ammine complex within months of wet ammonia exposure, low-level and high-level extract pickups because ammonia gas is lighter than air but ammonia vapour from a refrigerant pool sits low, eye-wash and emergency shower within 10 m of any ammonia connection, and an Ex-rated exhaust fan with EPL Gb motor or equivalent. The intermediate alarm at 25 ppm matches Safe Work Australia WES 8-hour time-weighted average for ammonia; the 35 ppm STEL triggers room evacuation alarm.

How do I specify ventilation for a forklift battery charging station inside a wholesale market?

Wholesale market forklift fleets at Sydney Markets, Melbourne Market and the Bidfood and PFD foodservice distribution centres are increasingly transitioning from diesel reach trucks to electric forklifts with either flooded lead-acid or lithium-iron-phosphate LFP batteries. Lead-acid charging releases hydrogen H2 at the end of the charge cycle (above 80% state of charge), driving the ventilation requirement under AS/NZS 5139 and IEC 62485-3 — minimum dilution airflow Q equals 0.05 times n times I times Cn divided by 1000 cubic metres per hour, where n is the number of cells in series, I is the gassing current and Cn is the rated capacity. Practically, this works out to 4-6 air changes per hour minimum in a dedicated charging bay, increasing to 10-15 ACH if 20-plus chargers run concurrently. Specify spark-resistant aluminium or 316L stainless supply ductwork because hydrogen rises and accumulates at ceiling level — galvanised is acceptable on lower-level return ducts. For LFP charging the H2 release is negligible and AS/NZS 5139 imposes thermal runaway propagation limits and NFPA 855 separation distances rather than dilution ventilation. Always provide H2 detection at ceiling level with alarm at 1% of LEL and shutdown at 25% LEL.

What construction standard applies to ductwork in a public retail Sunday market food court?

Most major Australian wholesale produce markets — Paddy's Markets at Flemington run by Sydney Markets Limited, the Saturday public retail session at Brisbane Markets, the Adelaide Produce Markets public Sunday session — host a public retail market with food court tenants alongside the wholesale trading floor. The food court ductwork falls under AS 1668.1 (fire and smoke control), AS 1668.2 (mechanical ventilation at V_p 10 L/s/person under Table 3.1 retail category), AS 4254 ductwork construction, and for commercial kitchen exhaust on Asian wok stations or grill cooking lines, the NFPA 96 grease duct construction standard (referenced by the National Construction Code through AS 1851 and the Building Code of Australia). Grease ducts in food courts are 16-gauge welded liquid-tight 316L stainless minimum, with full continuous welds on all longitudinal and transverse seams, slope to drain at 50 mm per metre, fire-rated enclosure per AS 1530.4 (typically 2-hour rating for a tenancy duct rising through more than one floor), and integrated AS 1851 wet chemical or water-mist suppression.

What is the temperature, humidity and air change specification for citrus, stone fruit and berry cool rooms at a central market?

Citrus and stone fruit cool rooms at central markets like Sydney Markets, Melbourne Market and Brisbane Markets typically run at 0-2 degrees Celsius and 90-95% relative humidity, with 15-25 air changes per hour to maintain product zone uniformity. Berry cool rooms — strawberry, blueberry, raspberry consignments from Costa Group and Driscoll's Australia — run at 0-2 degrees Celsius and 90% relative humidity at 12-20 ACH. Mushroom cool rooms hold 1-4 degrees Celsius and 90-95% RH with active CO2 control because mushrooms continue to respire and produce CO2 at low temperature — limit CO2 to under 1500 ppm in the mushroom storage envelope or accept flesh browning. The duct material specification across these cool rooms is G90 galvanised supply ducts with closed-cell PIR insulation and continuous foil vapour barrier, 304 stainless return ducts where daily caustic washdown is part of HACCP cleaning, and panel-insulated 316L stainless internal supply ducts where 100% RH service environments require complete corrosion immunity. SBKJ supplies all three material variants on the SBAL-V auto duct line in a single tooling configuration.

How long is the duct package lead time for a complete wholesale market HVAC fit-out?

A full duct package for a new wholesale fresh produce market or fish market — trading floor mechanical ventilation, cold room bank supply and return, banana ripening rooms, flower cool rooms, ammonia plant room emergency extract, fish gut waste extract, forklift charging bays and public retail food court — typically runs 16 to 22 weeks from approved drawings to final on-site delivery if fabricated on Australian SBKJ-supplied production lines, or 22 to 28 weeks if material is mixed galvanised and 316L stainless with welded longitudinal seam construction in the fish and ripening zones. The Sydney Fish Market 836-million-dollar Blackwattle Bay redevelopment is on a 24-month design and commissioning timeline of which the HVAC duct package consumes roughly 14 to 18 months from concept to handover. For the smaller central market upgrades — Adelaide Produce Markets, Perth Markets, the Hobart Showgrounds expansion — a 12 to 16 week duct package window is realistic provided drawings are stable and material is locked early.

Which SBKJ machines does the SBKJ Engineering Team recommend for an Australian wholesale market duct package?

SBKJ specifies the SBAL-V auto duct production line in galvanised G90 variant for general trading floor supply and return ducts (16 m/min line speed, 87 kW total installed power, 0.5-1.5 mm gauge range, 1500 mm coil width), the SBAL-V in 316L stainless variant for fish gut waste extract and the ammonia compressor room emergency exhaust, the SBTF-1500C spiral tubeformer for round supply trunks serving the cold room banks (also available as SBTF-1602 or SBTF-2020 for larger 1600 mm or 2000 mm round trunks), the SBFB-1500 flange and beading line for spiral cold room return riser ducts (7.5 kW, 1.20 m/min), the SBEM-1250 elbow former for tight spiral elbow geometry in the cold room and ripening room runs, the SBSF-1525 shearing line for plate work (2.5 kW), the SBLR-600 or SBLR-600A long-radius elbow former for low-pressure-drop trading floor mains (7.6 m/min), and the SBHF coil feeder line for high-throughput coil decoiling on multi-shift production. Spark-resistant aluminium production on the SBTF spiral line is the standard configuration for forklift battery charging station ducts. SBKJ ships every machine through the Box Hill North VIC office with full FAT records and AS/NZS 4254 compliance documentation.

How SBKJ supports wholesale market and fish market HVAC duct projects

SBKJ Group operates from Box Hill North, Victoria, supplying the auto duct production lines, spiral tubeformers, elbow formers and ancillary equipment that Australian HVAC fabricators use to produce the duct packages for wholesale fresh produce markets, fish markets, central markets, banana ripeners, flower cool rooms, ammonia compressor rooms, forklift charging bays and foodservice distribution centres. Where we add value to a market project:

• Material flexibility on a single tooling base — SBAL-V auto duct lines and SBTF spiral tubeformers configured for G90 galvanised, 304 stainless and 316L stainless with rapid changeover, allowing a single fabricator to cover the full material mix across a market envelope.
• Welded longitudinal seam tooling — factory option on the SBAL-V for the controlled-atmosphere ripening room, the ammonia compressor room emergency exhaust, the fish gut waste extract, and the NFPA 96 food court grease duct — a 4-6 week longer lead time but the only acceptable construction for these zones.
• Spark-resistant aluminium configuration on the SBTF spiral tubeformer for forklift lead-acid charging bay ducts where AS/NZS 5139 and IEC 62485-3 hydrogen dilution applies.
• Mill certificate traceability — every coil traceable to mill cert, every batch documented for HACCP, AS 4326, FSANZ and EPA boundary emission audit defensibility.
• FAT under your specification — Factory Acceptance Test runs your nominated coil through a full production cycle before shipment, with AS/NZS 4254 compliance documentation and third-party witnessed FAT on request.
• Australian operations — Box Hill North VIC office for English-speaking specification, after-sales and field support across the Australian and New Zealand wholesale fresh produce, fish market, banana ripening and foodservice distribution sector.
• Sector expertise — engineers with deep experience in the specification regimes covered in this guide. See our cold storage and cold chain HVAC duct guide, supermarket and grocery HVAC duct guide, aquaculture and seafood HVAC duct guide and distribution warehouse and logistics HVAC duct guide for related guidance.

Discuss your wholesale market or fish market duct project with an SBKJ engineer →