Distribution Warehouse, Fulfilment Centre & Logistics Hub HVAC Ductwork Guide

Why distribution warehouses are the dominant industrial HVAC project in Australia

Industrial property is the largest single property asset class under construction in Australia in 2026, and distribution warehousing is the largest single segment within it. Goodman Group, Charter Hall, ESR Australia, Logos and Centuria — the five largest industrial REITs by gross lettable area — collectively have more than four million square metres of distribution warehouse, fulfilment centre and logistics hub floor space either under construction, in fit-out or in approval phase across the period from 2024 to 2030. The federal HALE (Housing Australia Logistics Expansion) pipeline, state government inland-port investment, and the e-commerce penetration rate (which crossed 18 percent of total retail sales in 2025) all indicate the segment will continue to grow at 7–9 percent compound annual growth through the rest of the decade.

From an HVAC engineering standpoint, this segment is unusual. The typical Australian distribution warehouse is 50,000–150,000 m² of floor plate under a single roof, with 10–15 m clear internal height, a roof structure designed for 25–40 kg/m² of solar PV loading, multiple roller-door dock arrays at low level, and a small two-storey office and amenities block at the front. The HVAC system has to provide outdoor air to a low-occupancy bulk storage zone, conditioned air to high-occupancy pick-and-pack and dispatch areas, dedicated environmental control to AS/RS automated storage aisles, exhaust ventilation to battery charging rooms, and full smoke management to AS 1668.1 and AS 4391 — all in the same building, often under the same air handling envelope, and frequently with cold storage in the same compound or even the same building shell. The duct system that delivers all of this is dominated by spiral round trunks of 1,500–2,500 mm diameter, fed from 4–10 roof-mounted air handling units, and the duct contractor producing those trunks is almost always running a continuous spiral tubeformer line for the mainline runs and a separate auto duct line for the rectangular branches and office work.

This guide is written for the consulting engineers, design-and-construct contractors, head contractors, and HVAC ductwork sub-contractors specifying and producing ducts for these projects in the Australian market — and for the industrial property tenants and landlords approving the design. It assembles the code stack, the climate envelope, the zoning logic, the duct sizing approach, the AS/RS and cold-storage edge cases, the operator-specific notes for the major Australian distribution operators and the industrial REIT developers, and the SBKJ machine configuration that produces the necessary ductwork at scale.

Code stack — what governs HVAC duct design in an Australian distribution warehouse

The applicable code stack for a typical large-floor-plate distribution warehouse in Australia is denser than first-time specifiers usually expect. The headline code is AS 1668 in its two parts — AS 1668.1 for smoke management and AS 1668.2 for outdoor air — but at least seven other Australian and international standards regularly apply. Here is the working list our engineers run through on every fulfilment-centre HVAC review:

• NCC (National Construction Code) Volume One — classifies the building (Class 7b for storage warehouses, Class 8 for manufacturing or processing on-site, Class 5 for the office portion at the front), sets fire resistance levels, occupancy density, and triggers the AS 1668 series.
• AS 1668.1 — mechanical smoke management. Applies to most large warehouses, prescribes powered smoke exhaust at the roof apex sized to maintain a smoke-free layer above the highest sprinkler head, integrated with sprinkler activation and roller-door make-up air.
• AS 1668.2 — outdoor air for general ventilation. Sets the outdoor air rate per zone — typically 0.3–0.5 L/s/m² for bulk storage, 10 L/s/person for picking and packing zones, with separate elevated rates for battery charging, fuel handling and process exhausts.
• AS 1668.4 — natural ventilation calculation method. Often used in combination with AS 1668.2 to credit roof reliefs, louvres and stack ventilation toward the storage outdoor-air requirement.
• AS 4391 — smoke control in large enclosures. Applies to warehouses over 18,000 m² floor area (most modern DCs qualify), prescribes design parameters for natural and powered smoke exhaust, smoke layer interface height, and make-up air.
• AS/NZS 3666 — air-handling and water systems for buildings. Microbial control, cooling tower and evaporative cooler operation. Applies to any chilled-water plant feeding the AHUs.
• AS 5034 — installation of secondary batteries. Applies to forklift battery charging rooms (lead-acid) and prescribes hydrogen evolution exhaust ventilation rates.
• AS/NZS 4254 — ductwork for air-handling systems in buildings. The dominant Australian duct standard, prescribes leakage classes (A, B, C, D), reinforcement, joint construction, and sealing requirements.
• ASHRAE 62.1 — ventilation for acceptable indoor air quality (US standard, broadly equivalent to AS 1668.2). Used as a cross-reference on multinational fit-outs (Amazon, DHL, FedEx) and on projects led by US-based engineering consultancies.
• ASHRAE 90.1 — energy standard for buildings except low-rise residential. Used as a cross-reference for fan-energy budgets and economy-cycle requirements.
• NABERS for Industrial — voluntary energy and emissions rating that has expanded in recent years to cover logistics warehouses, refrigerated DCs, and AS/RS sites. Now appears on tender requirements from most major industrial REITs.
• Green Star — Industrial — Green Building Council of Australia rating tool for industrial buildings, with credits for ventilation effectiveness, IAQ monitoring, and refrigerant selection.

For full reference on AS 1668.2 outdoor air calculations as they apply across building classes, see our companion guide on AS 1668.2 — the Australian ventilation code reference. The remainder of this guide assumes the reader is broadly familiar with the AS 1668.2 calculation method and focuses on how the code stack is applied in distribution warehouse, fulfilment centre and logistics hub design.

Climate — designing for Australian summer extremes

The Australian climate envelope is the second-most-cited reason large-floor-plate logistics buildings differ from European or North American equivalents. Australian Building Codes Board climate zones place Melbourne and Sydney in zone 6, Brisbane in zone 2, Perth in zone 5, Adelaide in zone 5, Darwin in zone 1, and Hobart in zone 7. Across these zones the summer 99 percent peak design temperature ranges from 32°C in Hobart to 45°C in inland NSW and WA, with humidity loads in zones 1 and 2 (Darwin, Brisbane, Townsville) adding 10–18 g/kg moisture content on a typical summer afternoon.

The practical consequence for distribution warehouse HVAC is that the building has to handle a 35–45°C ambient with strong solar gain through the roof for 4–6 hours a day, every day, for roughly 60–90 days a year in most major distribution markets. On a 100,000 m² floor plate with a typical insulated metal roof at R3.0 thermal resistance, the steady-state cooling load through the roof alone reaches 6–9 MW at peak summer — before counting any internal heat gain from forklift trucks, conveyor motors, AS/RS shuttles, lighting, or pick-and-pack activity. This is why partial conditioning — conditioning only the lower 4–6 m of the air column where the workforce and the racked stock actually sit — is the dominant Australian fulfilment centre approach. Conditioning the full 14 m air column would push the chiller plant to 20–25 MW on a 100,000 m² site, which is rarely commercially justified.

Three climate-driven design decisions cascade out of this:

• Air-side economy cycle is mandatory. When the outdoor air falls below the indoor target temperature (overnight, early morning, and through autumn and winter), economy cycle mode brings 100 percent outdoor air across the AHU coils, drives indoor temperatures down, and pre-cools the racked stock. Typical Australian DC AHUs run economy cycle 3,500–4,500 hours per year — more than half the operating year.
• Solar PV roof integration is now standard. Goodman, Charter Hall, ESR and Logos all specify 10–25 kg/m² rooftop solar PV loading on new builds, generating 2–6 MW peak DC power on a 100,000 m² roof. The HVAC plant runs largely on the solar generation profile during the day, drawing from the grid only at peak summer load and overnight.
• Destratification fans are not optional. The 8–12°C floor-to-roof stratification on a hot summer afternoon means the racked stock at the top of the racking sees substantially hotter air than the picking face. HVLS destratification fans on 7–8 m diameter blades at roof level mix the column on demand and protect the upper-rack stock from heat damage. On a 100,000 m² site, expect 12–20 HVLS fans installed.

Zoning — how to divide a 100,000 m² floor plate

Modern Australian fulfilment centres are not monolithic spaces. The typical zoning we see on a 100,000 m² floor plate is:

• Bulk storage zone (40–60 percent of floor area, low occupancy, ambient ventilation only or partial conditioning).
• AS/RS automated storage aisle bank (10–25 percent, high-density vertical storage with shuttle robots, dedicated conditioned air at 18–24°C and 50–60% RH).
• Goods-to-person picking stations (5–10 percent, very high occupancy, fully conditioned at 22°C, with elevated outdoor air for the high pick-station density).
• Packing and dispatch zones (5–15 percent, high occupancy, fully conditioned, with conveyor transfers to outbound dock).
• Inbound dock and unloading zone (5–10 percent, high air-leakage when roller doors open, partial conditioning with dock seals and air curtains).
• Outbound dock and dispatch zone (5–10 percent, similar to inbound).
• Battery charging room (1–3 percent, dedicated mechanical exhaust under AS 5034).
• Fuel handling and refuelling zone for diesel forklifts (small, dedicated exhaust).
• Forklift maintenance bay (small, oil-mist and exhaust capture).
• Office, training, lunchroom and amenities block (5–10 percent, separate VRF or rooftop packaged HVAC, rectangular TDF-flanged duct).
• Cold-storage zone if applicable (5–25 percent, fully isolated with vapor barrier and dedicated refrigeration plant — see the SBKJ cold storage HVAC guide for full detail).

Each of these zones has its own outdoor-air calculation, conditioning strategy, and duct distribution method. Lumping them all under one AHU and one main supply trunk produces a system that under-serves the high-occupancy zones and over-conditions the low-occupancy zones — both fan-energy waste and code non-compliance.

Air handling unit selection and roof-top placement

The dominant air-handling configuration on Australian fulfilment centres is 4–10 packaged rooftop AHUs distributed across the floor plate, each rated 30,000–80,000 L/s supply airflow. The rationale for distribution rather than a single large central plant is:

• Duct runs stay short. Distributing AHUs keeps every supply main under 80 m, which keeps spiral duct diameters in the 1,500–2,500 mm range rather than the 3,000+ mm range a centralised plant would require.
• Pressure loss stays low. Short ducts at 8–12 m/s velocity produce 100–250 Pa of total system static pressure, which keeps fan energy at 1.2–1.8 W per L/s (the NABERS-competitive band).
• Maintenance access is simpler. Roof-mounted packaged units are accessed from the roof via a maintenance walkway and crane lift points, without entering the live distribution floor below.
• Redundancy is cheaper. Eight AHUs at N+1 redundancy adds one extra unit; one big AHU at N+1 redundancy adds one big unit at full capital cost.

Each AHU is typically a packaged rooftop unit with full chilled-water or DX cooling, gas heating for cold morning warm-up, full economy cycle damper assembly, and integrated heat recovery (typically a thermal wheel or plate exchanger) on the outdoor-air pathway. The unit drops a single main supply spiral trunk through a roof penetration and feeds a tree of branch trunks distributed across the underside of the roof structure.

Main supply trunk sizing — why 1500–2500 mm spiral dominates

For a typical 50,000 L/s rooftop AHU at 10 m/s design velocity, the main supply trunk required cross-sectional area is 5.0 m². The equivalent spiral round duct is 2,524 mm diameter — round up to a stocked size, that is 2,500 mm spiral. For a smaller 30,000 L/s AHU the equivalent diameter is 1,955 mm — a 2,000 mm spiral. For a 15,000 L/s smaller AHU it is 1,382 mm — a 1,400 or 1,500 mm spiral.

Why round spiral dominates rectangular at these sizes:

• Friction loss is roughly 30 percent lower for round versus rectangular at equivalent cross-sectional area — a direct fan-energy saving.
• Leakage class is higher — properly produced spiral routinely tests at AS/NZS 4254 Class C (under 4 percent leakage at design pressure), where rectangular field-built duct typically tests at Class B (under 6 percent).
• Fabrication labour is lower — a continuous spiral tubeformer running at 25–40 m/min produces hundreds of metres of duct per shift, whereas rectangular requires sheet cut, fold, seam, and flange assembly per length.
• Crane lifts are simpler — round duct in 6 m lengths is easy to rig and slot into hangers; large rectangular is awkward.
• Acoustic performance is acceptable at the 8–12 m/s velocities typical of warehouse mainlines (whereas rectangular duct can resonate and rumble at high velocity).

SBKJ spiral tubeformers in the SBTF-1602 (up to 1,600 mm) and SBTF-2020 (up to 2,000 mm) ranges produce these mainline diameters continuously. For diameters above 2,000 mm, the duct contractor either jumps to a larger SBKJ machine or constructs the trunk as multiple parallel 2,000 mm spirals at the AHU outlet. Production is from 0.8–1.5 mm galvanised coil for ambient supply, 1.0–1.5 mm pre-insulated double-skin coil for conditioned supply through unconditioned roof voids, and 0.8–1.2 mm galvanised for return and exhaust mains.

For full detail on spiral duct production technique, see the SBKJ spiral duct forming guide.

Branch and terminal distribution

From the main supply spiral trunk, the duct system steps down through branch trunks to terminal distribution. The dominant Australian fulfilment centre approach is to drop spiral terminal mains from the underside of the main trunk to roughly 4–6 m above the floor — high enough to clear the racking system and forklift truck travel envelopes, low enough to be in the occupied zone where the conditioning is needed. From the dropped terminal mains, adjustable jet diffusers or large-throw nozzles supply conditioned air horizontally across the picking face.

For AS/RS automated storage aisles, the approach is different. Instead of bulk-floor distribution, dedicated dropped spiral mains run down each AS/RS aisle, supplying chilled and dehumidified air directly to the picking face via slot diffusers at picking-shuttle elevation (1.5–2.5 m). The aisle return path is via low-level grilles at the aisle ends. This delivers the tight 18–24°C and 50–60% RH band that the AS/RS shuttle electronics require, without conditioning the cubic volume of the entire racking aisle.

For pick-and-pack stations and goods-to-person Amazon Robotics workstations, the air supply is via overhead linear slot diffusers on a dedicated branch, with a return path via the bulk floor system. Pick stations typically have a higher outdoor-air rate — 15–25 L/s/person — because of the elevated occupant density at the workstation cluster.

Destratification fans and the 8–12°C ceiling problem

On a 12 m clear-height warehouse on a 40°C summer day, the air at roof level is typically 8–12°C hotter than the air at the picking face. Three things make this happen:

• Solar gain through the roof structure heats the underside of the roof deck to 50–60°C.
• Buoyancy drives the heated air upward to accumulate at the apex.
• Without intervention, the stratified hot layer grows downward through the day until it reaches the conditioned occupied zone.

Three interventions defeat the stratification:

• Roof-mounted relief or powered exhaust at the apex — vents the stratified hot layer to atmosphere. On a 100,000 m² site, expect 15–30 powered roof exhaust fans rated 5,000–15,000 L/s each.
• HVLS destratification fans at roof level — re-mix the air column on demand. On a 100,000 m² site, expect 12–20 HVLS fans on 7–8 m diameter blades, drawing 1–2 kW each at low rotation. They run continuously through summer for destratification and reverse direction in winter to drive warm air down to the floor.
• Insulated roof structure at R3.0 minimum thermal resistance to limit the solar-gain heat input at source.

AS/RS automated storage — the highest-spec zone in the building

AS/RS (Automated Storage and Retrieval Systems) are the fastest-growing segment of Australian distribution warehousing. Coles has installed major AS/RS at Truganina VIC and Redbank QLD over 2024–2025; Woolworths has multiple AS/RS sites in operation including Moorebank Logistics Park NSW and Truganina VIC; Amazon's Kemps Creek NSW fulfilment centre uses goods-to-person robotics at scale; JD Sports Truganina uses AutoStore-type cube AS/RS; and the Goodman, ESR and Logos pipelines for 2026–2030 include further AS/RS-equipped speculative builds across Melbourne, Sydney, Brisbane and Perth.

From an HVAC standpoint, AS/RS aisles are the highest-spec zone in the building. The shuttle and crane electronics, the sensors on the picking face, and the lithium-ion battery packs in the autonomous mobile robots (AMRs) all operate inside a temperature, humidity and dust-quality envelope that bulk warehouse ambient cannot meet. Typical AS/RS environmental specifications are:

• Temperature — 15–30°C continuous, with a tightening to 18–24°C around picking stations and the central aisle servers.
• Humidity — 40–70% RH, controlled to avoid both static-electricity buildup at low RH (which damages electronics) and condensation on cold racking faces at high RH.
• Air cleanliness — ISO 14644 Class 9 or cleaner is typical, achieved with filter-bank pre-conditioning of the supply air. Dust accumulation on shuttle bearings, conveyor wheels and PCB surfaces is the leading cause of unscheduled AS/RS downtime.
• Air movement — gentle, with no high-velocity jets at the picking face that could disturb light items or affect lift-and-place accuracy.
• Pressure — slight positive pressure relative to surrounding bulk storage to keep dust migration outward.

Meeting this envelope means dedicated AHUs serving the AS/RS aisle banks, with chilled water cooling, dehumidification (often a separate dedicated outdoor air system, DOAS, ahead of the AHU), high-efficiency filtration (F7 or F8 minimum), and dedicated spiral supply mains down each aisle. The duct contractor on an AS/RS project typically produces 30–50 percent more spiral metres per square metre of floor area than on a bulk warehouse — the dropped-aisle distribution adds substantial spiral footage.

Cold storage adjacent — vapor barrier integrity at the boundary

Many Australian fulfilment centres include cold storage in the same compound — sometimes in a fully separate building, sometimes in an attached wing of the same shell, sometimes (as in Coles and Woolworths grocery DCs) integrated as ambient, chilled, and frozen zones in a single building. The HVAC engineering implications are significant. Where ambient and cold storage share a wall:

• Vapor barrier integrity is the single most failure-prone detail. The cold side has a continuous vapor-tight envelope on the warm face of the insulation. Every penetration through that envelope — duct sleeves, refrigeration pipework, electrical conduit, sprinkler pipework — is a potential failure point. A single un-sealed duct penetration delivers 5–15 kg/day of moisture into the cold store, which condenses and freezes on the evaporator coils, doubling the defrost cycle frequency and pushing the refrigeration plant toward overload.
• Dedicated air handling on each side with no shared returns is mandatory. A shared return air path at a temperature transition between ambient and cold is impossible to dehumidify economically.
• Insulated double-skin spiral at all penetrations through the cold-store wall, with butyl-rubber vapor-tight sealing at the warm face and a thermal-break sleeve at the wall transition.
• Dock-seal vestibules at fork-truck doors between ambient and cold-storage zones, preventing direct mixing during transfer events.

For full design detail on cold storage HVAC, including evaporator placement, anti-condensation supply patterns, frozen-store door seals and refrigeration interaction with the duct system, see the SBKJ cold storage HVAC guide.

Battery charging zones — AS 5034 hydrogen ventilation

Almost every distribution warehouse in Australia operates a fleet of forklift trucks. The traditional fleet is electric lead-acid forklifts charging from a battery rack overnight; the contemporary fleet is increasingly lithium-ion, charging in shorter bursts during shift changes. Both require dedicated ventilation, but for very different reasons.

Lead-acid charging produces hydrogen gas (H₂) during the gas-evolution phase of charging. AS 5034 (Installation of secondary batteries) prescribes mechanical ventilation sized to keep hydrogen evolution below 1 percent of the lower explosive limit (LEL) — practically, 0.5–1.5 L/s of exhaust per ampere-hour of installed charging capacity. The ventilation has to be:

• Dedicated — not shared with general warehouse ventilation, because hydrogen is lighter than air and accumulates at ceiling level.
• Captured at the source — exhaust hood directly above the charging racks, capturing hydrogen at the point of evolution.
• Discharged safely — to atmosphere via a dedicated spiral exhaust duct routed at least 3 m clear of any air intake or ignition source.
• Continuously running during charging cycles, with interlock to charging-circuit power so that loss of ventilation halts charging.

Lithium-ion charging produces no hydrogen but introduces a different hazard — thermal runaway. A failed lithium-ion cell can self-ignite and propagate cell-to-cell at temperatures above 60°C. AS 5034 does not currently cover lithium-ion ventilation in detail, but industry best practice (and increasingly fire-engineered design briefs) treats lithium-ion battery rooms as dedicated fire compartments with high-rate exhaust, smoke detection, and gas suppression systems. The HVAC duct system contributes the smoke exhaust and make-up air, often via dedicated insulated spiral risers separate from the main warehouse system.

E-commerce fulfilment — Amazon Robotics, goods-to-person and packing zones

Amazon Australia, Coles Online, Woolworths Online, Catch, JD Sports, The Iconic, Kogan and most large e-commerce operators in the Australian market run goods-to-person picking — an automated system in which racks of goods are brought to a stationary human picker by autonomous mobile robots (AMRs) or shuttles. The picker stays at a workstation; the goods come to them. The throughput is 200–400 picks per hour per worker — three to five times the rate of a traditional walk-and-pick system.

From an HVAC standpoint, the goods-to-person workstation zone has a unique profile:

• Very high occupancy density — 100–300 workers in a 2,000–5,000 m² zone, all stationary at workstations.
• Sedentary metabolic load — the workers are seated or standing in one spot, so the cooling load per worker is lower than for walking pickers.
• High electrical heat gain — workstation monitors, scanners, label printers, conveyor motors, and the AMR battery-charging stations all add internal heat.
• Tight comfort window — repetitive-motion workers complain rapidly when temperature drifts outside 21–24°C.
• Cleanliness preference — the workstations handle consumer goods, often final-customer-facing packaging, so visible airborne dust is a concern.

The duct distribution into a goods-to-person zone is typically via overhead linear slot diffusers on a dedicated AHU branch, with a return path either via low-level grilles or via the bulk warehouse return system. Outdoor air at the workstation cluster is typically elevated to 15–25 L/s/person to compensate for the high occupant density.

Packing and dispatch zones operate at slightly lower occupant density but with more material handling — cardboard cartons, paper labels, packing tape — that generates fine particulate. The HVAC distribution is similar to goods-to-person but with a higher filtration grade (F8 minimum) on the supply path and a particulate-management exhaust at the cardboard-cutting and tape-dispensing stations.

Smoke management — AS 1668.1 and AS 4391

Most large Australian distribution warehouses qualify for AS 4391 (smoke control in large enclosures) by virtue of exceeding the 18,000 m² floor-area threshold. AS 4391 applies in addition to the AS 1668.1 general smoke management requirements, and prescribes design parameters for:

• Smoke layer interface height — the height above floor at which the smoke-free layer ends and the smoke-laden layer begins. For a 12 m warehouse, typical interface design is 2.5–3.0 m above the highest racking level, leaving 9 m of stratified smoke layer above.
• Smoke exhaust rate — typically 1.5–4.0 m³/s per powered roof exhaust fan, with multiple fans operating simultaneously on detection. Total smoke exhaust capacity on a 100,000 m² warehouse is 80,000–250,000 L/s.
• Make-up air rate — equal to the smoke exhaust rate, automatically delivered via roller-door interlocks (the dock doors open on smoke detection to provide the make-up path) or via dedicated low-level make-up air dampers.
• Smoke reservoir compartmentation — for warehouses over 100,000 m², the floor area is divided into smoke reservoirs of 10,000–20,000 m² each, separated by smoke curtains that drop on detection.

The smoke management duct system is typically separate from the comfort HVAC duct system. Smoke exhaust uses dedicated spiral risers from the apex of the building down to dedicated smoke exhaust fans located on a fire-rated mechanical platform. The risers are sleeved with fire-rated insulation (1–2 hours) and the fan motors are temperature-rated to 250–400°C operating environment. Make-up air paths through the roller doors are coordinated with the building's fire indicator panel.

Smoke management drives the largest single duct flow in the building — a 100,000 m² warehouse smoke exhaust at 200,000 L/s through 20 powered roof fans implies individual exhaust trunks of 1,500–2,500 mm diameter, equal to the comfort supply mains. SBKJ SBTF-2020 spiral lines produce both, often from the same coil stock.

Sprinkler interaction — clearances and routing

Almost every modern Australian distribution warehouse uses ESFR (Early Suppression Fast Response) sprinklers at ceiling level, often supplemented by in-rack sprinklers within the racking system. ESFR design has tight clearance rules around the sprinkler head spray pattern, which constrain duct routing more than standard sprinkler design:

• Minimum 450 mm clearance from any sprinkler head to the nearest duct underside — to avoid blocking the spray pattern.
• Main supply trunks routed below the sprinkler grid rather than above, where possible — keeps the spray pattern clear at high level.
• In-rack sprinkler clearance on AS/RS aisles — the dropped supply spiral cannot block the access path of the in-rack sprinkler.
• Duct hangers coordinated with sprinkler pipe hangers — both systems share the roof structure for support.

The practical effect is that the duct designer works closely with the FPAA-compliant sprinkler designer from concept stage. Late-stage clashes between duct mains and sprinkler distribution are one of the highest-cost rework items on warehouse fit-outs.

NABERS for Industrial — duct system contributions to the rating

NABERS expanded its rating tools to cover industrial sites (logistics warehouses, refrigerated DCs, AS/RS sites) over 2023–2025, and the rating now appears on tender requirements from most major Australian industrial REITs and government-procured logistics. Goodman Group, Charter Hall, ESR, Logos and Centuria each publish target NABERS ratings (typically 4.5–5.5 stars for new builds) on their speculative developments.

The duct system contributes to the NABERS rating in three measurable ways:

• Fan power — total fan-watt-per-litre-per-second of supply airflow. Spiral mains at 8–10 m/s velocity, with low-leakage joints and properly sealed branches, deliver 1.2–1.6 W/L/s on a typical fulfilment centre — well within the NABERS-competitive band. Rectangular field-built duct often runs at 1.8–2.4 W/L/s, which can cost 0.5–1.0 stars on the NABERS rating.
• Duct leakage — measured at AS/NZS 4254 Class C minimum on a NABERS-targeted project. Spiral round duct routinely tests at Class C; rectangular field-built duct often defaults to Class B.
• Thermal loss in unconditioned roof voids — pre-insulated double-skin spiral on supply mains running through the roof void cuts thermal loss by 60–80 percent versus uninsulated single-skin. The heat-loss reduction reads directly into the AHU re-cooling load.

For a developer or tenant chasing 5.0 stars NABERS for Industrial on a new fulfilment centre, the duct specification is typically: spiral round mains at AS/NZS 4254 Class C, 8–10 m/s design velocity, pre-insulated double-skin where the duct passes through unconditioned roof voids, full leakage commissioning and certification, and a fan-energy budget of under 1.4 W/L/s.

Australian operator-specific notes — 2024-2030 project pipeline

The Australian distribution warehouse pipeline for 2024-2030 is dominated by a small number of large operators. The HVAC duct specification varies meaningfully by operator. Here is what the SBKJ engineering team has observed across the active project pipeline:

Amazon Australia

Amazon Australia operates fulfilment centres at Kemps Creek NSW (200,000 m² super-fulfilment centre, the largest in the southern hemisphere), Lyndhurst VIC (significant goods-to-person robotics), and Acacia Ridge QLD. The HVAC specification is dominated by US-style ASHRAE 62.1 outdoor air calculation cross-referenced to AS 1668.2, mandatory NABERS-equivalent commissioning, full goods-to-person workstation zoning at 22°C ± 1°C, and dedicated AMR battery-charging exhaust. Spiral round mains at Class C leakage are the default. Amazon's internal engineering standards run tighter than typical Australian commercial practice, particularly on filtration grade (F8 minimum on goods-to-person zones) and IAQ monitoring.

Coles Group

Coles operates AS/RS sites at Truganina VIC and Redbank QLD, alongside multiple traditional ambient and refrigerated DCs. The Coles AS/RS specification is the closest in Australia to a clean-manufacturing environment — tight 18–22°C, 50–60% RH band, F7 filtration minimum, dedicated AHUs per AS/RS aisle bank, and pre-insulated spiral throughout. The Coles refrigerated DCs use the cold-storage approach detailed in the SBKJ cold storage HVAC guide.

Woolworths Group

Woolworths runs major DCs including the Moorebank Logistics Park NSW site (~40,000 m² ambient with associated chilled and frozen zones) and Truganina VIC, plus the rapidly expanding network of Micro Fulfilment Centres (MFC) — typically 1,000–3,000 m² compact AS/RS sites attached to or near existing supermarkets, with around 50 sites either operational or in pipeline as of 2026. The MFC HVAC profile is unusual: a small floor plate, very high pick density, tight environmental tolerance, and often a constrained ceiling height because the site is co-located with a retail store. Spiral duct distribution is common but at smaller diameters (400–800 mm mains).

For grocery DC zoning, see the SBKJ supermarket and grocery HVAC guide.

Australia Post

Australia Post operates major parcel sortation facilities at Sunshine West VIC, Chullora NSW, Redbank QLD, and a growing regional network. The HVAC profile is largely ambient — parcels do not require conditioned storage — with conditioning concentrated at sortation conveyors, the operator workstations, and the office front. Smoke management dominates the duct sizing (parcel storage is a high fuel-load environment). Roof-mounted AHUs with full economy cycle and partial conditioning of the lower 4 m of the air column is standard.

DHL Supply Chain Australia

DHL operates 10+ DCs across Australia for various retail and industrial clients. Each site is configured to the client's profile, but the underlying HVAC pattern is consistent — spiral round mains, partial conditioning, NABERS-compliant fan budget, and dedicated battery-charging exhaust. DHL's internal "Operation Excellence" engineering standard often calls for higher commissioning rigour than the Australian default, including full duct-leakage testing on site before handover.

Linfox

Linfox is the largest privately-owned Australian logistics operator and runs DCs for retailers, grocery and bulk freight. Linfox-developed sites tend to follow industrial-REIT design standards (often Goodman or Charter Hall) on the building shell, with HVAC fit-out to the specific tenant operating model.

Toll Group (now part of Japan Post)

Toll's parcel and freight DC network is similar in profile to Australia Post — largely ambient with conditioning concentrated at workstations and offices. Following the integration with Japan Post, design standards on new builds increasingly mirror Japanese logistics-DC practice (slightly tighter commissioning and energy-efficiency targets than the Australian default).

JD Sports

JD Sports operates a major DC at Truganina VIC using AutoStore-type cube AS/RS — an extremely high-density, low-ceiling AS/RS format. The HVAC profile is an unusual hybrid: very tight conditioning on the AutoStore cube itself (15–25°C, 40–60% RH, F8 filtration, dust-controlled supply), with ambient ventilation in the surrounding pick-and-pack and dispatch areas. Spiral duct dominates throughout, with smaller diameters than a typical large-floor-plate DC because the AutoStore cube is more compact.

Bunnings

Bunnings operates major DCs including the Hoxton Park NSW site, supplying its retail store network. The HVAC profile is similar to Coles ambient DCs — large floor plate, partial conditioning, spiral round mains, AS 1668.1 smoke management, and forklift battery-charging exhaust. Bunnings' internal engineering standards align closely with the Wesfarmers group standard used across Coles, Officeworks and other retail DCs.

Catch

Catch (now part of Wesfarmers) operates an Ottery DC at Truganina VIC alongside other e-commerce fulfilment infrastructure. The HVAC profile follows Wesfarmers group standards — partial conditioning, NABERS-compliant fan budget, spiral round mains.

Industrial REIT design standards — Goodman, Charter Hall, ESR, Logos, Centuria

The five largest industrial REITs in the Australian market each publish industrial design standards that set the HVAC duct specification baseline for speculative developments. Across the five, the common elements are:

• Spiral round duct preferred for main supply trunks, with rectangular reserved for branches and AHU connections.
• AS/NZS 4254 Class C minimum leakage class on supply duct.
• NABERS-ready commissioning with full duct-leakage testing on site before handover.
• Solar PV roof loading at 10–25 kg/m² designed into the structure, with HVAC plant sized for solar generation profile.
• Fan energy budget at under 1.6 W/L/s for the comfort HVAC system.
• Pre-insulated double-skin spiral on supply mains running through unconditioned roof voids.
• Smoke management to AS 1668.1 and AS 4391, with dedicated smoke exhaust risers separate from comfort HVAC.

Goodman Group and Charter Hall publish more detailed engineering standards than ESR and Logos (both of which have shorter Australian operating histories), and Centuria's industrial standards are aligned with the Goodman approach. Matching the duct specification to the developer's published standard at the design stage avoids late-stage re-design at tender.

Energy efficiency — solar PV, LED, HVAC integration

Modern Australian distribution warehouses are increasingly net-zero-operational-carbon target buildings, particularly the Goodman Group "Net Zero" pipeline and the Charter Hall PRIME (Property Reaching Industry-Leading Maturity in ESG) portfolio. The energy efficiency strategy combines:

• Roof solar PV at 2–6 MW peak DC on a 100,000 m² roof, generating roughly 3,500–6,500 MWh/year of solar electricity.
• LED warehouse lighting with daylight harvesting at the skylight panels — a typical conversion from fluorescent to LED cuts lighting load by 50–65 percent.
• HVAC integration with the solar profile — the AHU plant runs harder during the solar peak (afternoon), pre-cooling the space, and idles overnight.
• Battery storage of 1–4 MWh on-site, smoothing the solar profile and reducing peak grid draw.
• Heat recovery on AHU outdoor air paths via thermal wheels or plate exchangers.
• Economy cycle running 3,500–4,500 hours per year on most of the AHU plant.
• Variable-speed fans on every AHU, modulating with internal load.

The duct system's contribution is to keep fan-energy as low as possible — through low-friction spiral mains, low-leakage joints, and thermally efficient pre-insulated double-skin on supply mains. On a 5.0-star NABERS for Industrial target, the duct system can be the difference between achieving and missing the rating.

Office and amenities block — separate HVAC envelope

Almost every Australian distribution warehouse has a small office and amenities block at the front — typically two storeys, 1,500–4,000 m² footprint, housing reception, training rooms, lunchroom, change rooms, manager offices and the operations control room. This block runs on a separate HVAC envelope from the main warehouse:

• VRF or rooftop packaged unit rated 100–400 kW thermal capacity.
• Rectangular TDF-flanged duct at 0.5–1.0 mm gauge, distributing through a suspended ceiling to ceiling diffusers.
• Outdoor air at AS 1668.2 office rates (typically 10 L/s/person at the AS 1668.2 base value, elevated to 15 L/s/person on Green Star projects).
• Tighter comfort tolerance than the warehouse — 22°C ± 1°C continuous, with humidity control on training rooms and the operations control room (which often houses the AS/RS control servers).

The rectangular ductwork for the office block is produced on a separate auto duct line — typically an SBKJ SBAL-III on the office portion of the project. For a comparison of SBAL-III versus SBAL-V auto duct lines see the SBKJ SBAL-V vs SBAL-III guide.

Bulk-storage minimal HVAC — when ventilation is just smoke spill plus roof exhaust

Not every warehouse needs full conditioning. For pure bulk-storage with low pick density, no AS/RS, no temperature-sensitive stock, and limited workforce on the floor, the HVAC system can simplify to:

• Roof reliefs and powered exhausts at the apex, sized to AS 1668.2 outdoor-air rates (0.3 L/s/m²) and AS 4391 smoke management.
• Roller-door make-up air via dock-door operation during inbound/outbound activity.
• Spot conditioning at offices, control rooms, and amenities only.
• HVLS destratification fans for thermal mixing.
• No ducted comfort HVAC on the main floor.

This approach applies to roughly 10–15 percent of Australian distribution warehousing — typically dry-goods bulk storage for industrial-supply customers, vehicle storage compounds, packaging materials, and seasonal stockholding warehouses. The cost saving versus full ducted HVAC is significant (capital cost roughly 35–50 percent lower), and on the right tenant profile it is the right answer. The duct contractor on these projects produces only the smoke exhaust risers, the office block ductwork, and the spot-conditioning runs to control rooms — typically 5–15 percent of the duct surface area of a fully ducted facility on the same footprint.

SBKJ machine configuration for the duct contractor

For an Australian HVAC duct contractor producing 50,000–200,000 m² of duct surface area per year on distribution warehouse, fulfilment centre and logistics hub projects, the standard SBKJ machine configuration is:

• SBKJ SBTF-2020 spiral tubeformer for main supply trunks — produces continuous spiral round duct from 100 mm to 2,000 mm diameter at 25–40 m/min from 0.5–1.5 mm galvanised, stainless or pre-insulated coil. This is the workhorse for the warehouse mainline and branch trunks.
• SBKJ SBTF-1602 spiral tubeformer as a secondary spiral line where the project mix includes substantial 200–1,600 mm distribution duct alongside the larger mains. Faster set-up between diameter changes than the SBTF-2020.
• SBKJ SBAL-III auto duct line for the rectangular TDF-flanged ductwork in the office block, plenum boxes, and short connections — produces complete TDF-flanged duct from 0.5–1.5 mm coil through coil decoiler, levelling, notching, edge forming, slitting, longitudinal seaming, TDF flange forming and cut-to-length in a single integrated line.
• Coil storage and handling at the contractor's workshop — typically 50–200 tonnes of galvanised, stainless and pre-insulated coil at a time, sized to the project pipeline.

This combination produces the full spectrum of ductwork required by a typical distribution-warehouse project, from the 2,000 mm spiral mains down to the 200 mm rectangular branches in the office. SBKJ's Box Hill North VIC engineering team sizes both machines to the contractor's exact coil specification before quotation, including coil width, gauge range, end-product diameter and length specification, and any pre-insulated double-skin requirements for the project pipeline.

For full machine specification detail, see the SBKJ machine catalogue.

Specifying ductwork on a new fulfilment centre — design walkthrough

To make this concrete, here is the design walkthrough we run when an Australian HVAC consulting engineer or duct contractor asks SBKJ to size machines for a typical 100,000 m² fulfilment centre with AS/RS, goods-to-person workstations, ambient bulk storage and a forklift battery charging room.

Step 1 — Establish the outdoor air demand

For 60,000 m² of bulk storage at 0.4 L/s/m², 24,000 L/s. For 20,000 m² of AS/RS at 0.5 L/s/m² with elevated rate for picking electronics, 12,000 L/s. For 10,000 m² of pick-and-pack at 50 workers per 1,000 m² and 15 L/s/person, 7,500 L/s. For 5,000 m² of dock zones at 20 workers and 10 L/s/person, 1,000 L/s. For 5,000 m² of office and amenities at 50 workers and 10 L/s/person, 500 L/s. Total approximate building outdoor-air demand: 45,000 L/s.

Step 2 — Design the AHU layout

Distribute eight rooftop AHUs across the floor plate at 30,000–40,000 L/s each total airflow (with outdoor-air fraction of 20–30 percent on typical operation, 100 percent on economy cycle). Total comfort airflow at the supply side is approximately 250,000 L/s, sized for a 10–12°C air-temperature differential to the conditioned occupied zone.

Step 3 — Size main supply trunks

Each 30,000 L/s AHU supplies a 1,955 mm diameter main trunk at 10 m/s — round up to a 2,000 mm spiral. Eight 2,000 mm main trunks total. Add the AS/RS dedicated AHUs (typically two more, smaller, at 15,000 L/s each) for AS/RS dedicated mains at 1,400 mm spiral. Total main-trunk spiral footage on a typical 100,000 m² site: approximately 600–900 m.

Step 4 — Size branch and terminal distribution

Branch trunks step down through 1,400 mm, 1,000 mm, 700 mm and 500 mm diameters across the floor plate. Terminal drops at 4–6 m above floor at 300–500 mm diameter, with adjustable jet diffusers. AS/RS aisle drops at 400–600 mm diameter, with slot diffusers at picking elevation. Total branch and terminal spiral footage on a 100,000 m² site: approximately 2,500–4,500 m. Total spiral footage: 3,100–5,400 m.

Step 5 — Add smoke exhaust mains

20 powered roof exhaust fans at 10,000 L/s each, with 2,000 mm spiral risers from the apex down to the fan platform — short risers but high diameter. Total smoke-exhaust spiral footage: approximately 200–400 m, plus exhaust trunks across the smoke reservoir compartments.

Step 6 — Add office and amenity rectangular duct

5,000 m² office block at typical fit-out density produces approximately 800–1,500 m² of rectangular TDF-flanged duct surface area on the SBAL-III auto duct line.

Step 7 — Calculate total annual duct production

For a duct contractor producing two such fulfilment centres per year, annual output is approximately 120,000–180,000 m² of duct surface area. The SBTF-2020 spiral line at 25–40 m/min runs single-shift for approximately 1,200–1,800 hours per year producing the spiral. The SBAL-III auto duct line runs single-shift for approximately 800–1,200 hours per year producing the rectangular. Both lines have spare capacity for additional projects in adjacent industrial sectors (cold storage, supermarket DCs, manufacturing warehouses, data centres).

FAQ

What outdoor air rate does AS 1668.2 require for distribution warehouses?

AS 1668.2 classifies bulk warehouses as low-occupancy storage and prescribes outdoor air on a per-area basis (typically 0.3–0.5 L/s/m² depending on contents and forklift activity), supplemented by a per-occupant rate (10 L/s/person) at picking, packing and dispatch stations. Battery charging zones, fuel-handling areas and maintenance bays carry separate, higher rates under AS 1668.2 Section 5 because of contaminant evolution.

Why are distribution warehouse main duct trunks 1500–2500 mm in diameter?

A 50,000–150,000 m² floor plate at 0.5–1.0 air change per hour with 10–14 m roof height generates total airflow in the 200,000–600,000 L/s range. Splitting that across 4–8 roof-mounted AHUs, each main supply trunk lands in the 1,500–2,500 mm diameter band at conventional duct velocities of 8–12 m/s. Spiral round duct dominates over rectangular for the long mainline runs.

Do AS/RS automated storage zones need temperature-controlled HVAC?

Yes — modern AS/RS shuttles, mini-loads and goods-to-person robots have dust-, temperature- and humidity-tolerance bands that bulk-warehouse ambient does not meet. Typical AS/RS specifications require 15–30°C, 40–70% RH, and ISO 14644 Class 9 or cleaner air quality at the picking face. Dedicated air handlers feed AS/RS aisles via dropped spiral mains with terminal grilles at racking elevation.

How do you ventilate a 12-metre-high warehouse without overcooling the ceiling?

Combine roof-mounted AHUs supplying through dropped spiral terminals at 4–6 m above the floor (the occupied zone), HVLS destratification fans at roof level on 7–8 m diameter blades to mix the air column, and roof-mounted relief or powered exhaust to expel hot air at the apex. Conditioning only the lower 4 m of the air column cuts cooling load by 35–45 percent versus full-volume conditioning.

What duct strategy works at the boundary between ambient and cold storage in the same building?

Best practice is a continuous vapor-tight envelope that the ductwork penetrates only at sealed sleeves, with separate air handling systems on each side, no shared return paths, and dedicated dock-seal vestibules at fork-truck doors. Duct penetrations through the cold-store wall use insulated double-skin spiral with thermal break sleeves and butyl-rubber vapor sealing.

What ventilation does a battery charging zone need under AS 5034?

AS 5034 prescribes mechanical ventilation sized to keep hydrogen evolution from charging lead-acid forklift batteries below 1 percent of the lower explosive limit. Typical design is 0.5–1.5 L/s per ampere-hour of installed battery capacity, captured by a dedicated exhaust hood directly above the charging racks and discharged to atmosphere via a separate spiral exhaust duct.

Can SBKJ machines produce ductwork at the diameters and gauges Australian distribution centres require?

Yes. SBKJ spiral tubeformers in the SBTF-1602 and SBTF-2020 ranges produce round spiral duct from 100 mm up to 2,000 mm diameter in galvanised steel, stainless steel and pre-insulated double-skin formats. For office, amenities and admin areas SBKJ SBAL-III auto duct lines produce rectangular TDF-flanged duct from 0.5–1.5 mm gauge sheet stock.

How does NABERS for Industrial change duct selection on a new fulfilment centre?

The recent NABERS expansion to industrial sites means duct system fan power and leakage now feed directly into the building's NABERS rating. Spiral round duct has lower friction loss than rectangular for equivalent cross-sectional area and tests below 4 percent leakage at AS/NZS 4254 Class C — both contribute to lower fan energy and a higher NABERS star rating. New developments are increasingly specifying spiral as the default trunk format.