Why service stations are the most complex small footprint in the HVAC catalogue
A modern Australian service station looks deceptively simple from the kerb — a steel canopy, a row of dispensers, an LED price sign, a glass-fronted convenience store. Engineer the HVAC ductwork inside and around that footprint and the complexity reveals itself quickly. On a single 1,200 m² site you may have to integrate retail air conditioning at 22–24 °C, a customer toilet exhaust, a 2–4 °C cool room for drinks and dairy, a hot-food display, a barista coffee station, sometimes a full quick-service kitchen, a tobacco room with separate air handling, a back-of-house staff room, a workshop or service bay on older legacy sites, and — overlapping all of this — an envelope of hazardous-area classification driven by fuel vapor, LPG cylinders, vent risers and tanker offload points. Layer in DC fast charging cabinets, battery energy storage, hydrogen refuelling pilots and the regulatory creep of vapor recovery and you have one of the densest small-footprint HVAC challenges in Australian construction.
The duct contractor who walks onto a service station refurbishment without a structured understanding of the overlapping codes — AS 1668.2 for ventilation, AS/NZS 60079 for hazardous areas, AS 1940 for flammable liquids, AS 1596 for LPG, AS 5034 for EV charging — will burn weeks in clarification requests and risk rework that delays site reopening. The forecourt operator earns nothing while the station is closed; every day of delay is a measurable loss against the operator's quarterly trading update. SBKJ has supplied HVAC duct machinery and consulted on duct fabrication for fuel retail builds across the Pacific market for more than two decades, and this guide consolidates what we have learned into a single reference.
It is written for two audiences. First, HVAC contractors, sheet-metal fabricators and design consultants who are tendering or pricing service station and convenience store work. Second, asset managers and project leads inside the Australian fuel retail majors — Ampol, BP Australia, Viva Energy, 7-Eleven Australia, EG Group Australia, United, Liberty and Peregrine Corporation (OTR) — who want a vendor-side perspective on what good ductwork looks like before signing a refurbishment package.
Section 1 — The Australian fuel retail landscape in 2026
The Australian fuel retail market has consolidated heavily in the past decade and continues to shift. Three structural forces matter for HVAC duct contractors. First, vertical integration — the refiner-marketer model where Ampol and Viva Energy own both refining (or import terminals) and the retail network, while BP has divested its Kwinana refinery and is now an importer-marketer. Second, convenience retail mix — every major operator has shifted from "petrol station with a kiosk" to "convenience store with fuel" with food, coffee, parcel lockers and increasingly EV charging built into the proposition. Third, electrification — the forecourt is becoming a multi-energy site combining liquid fuel, LPG, DC fast charging and, on pilot sites, hydrogen.
Ampol (ASX:ALD) — around 1,900 sites
Formerly known as Caltex Australia and rebranded to Ampol in 2020, Ampol operates the largest branded network in Australia at roughly 1,900 retail sites. Its in-house convenience brand The Foodary has been rolling out across capital-city sites since 2018, combining a barista coffee bar, fresh-food deli, and an expanded grocery selection. Ampol also operates the Lytton refinery in Brisbane, which is transitioning from refining to an import terminal model. Ampol's EV charging brand is AmpCharge, with sites typically equipped with 75–150 kW DC fast chargers. For HVAC duct contractors, an Ampol Foodary site typically requires 22 °C interior set point, NC-40 acoustic target, full kitchen exhaust system to AS 1668.1, and a separate Ex-rated exhaust on any LPG cylinder cage. New-build and major refurbishment ductwork is overwhelmingly galvanised mild steel to AS/NZS 4254 for retail areas, with a stainless option specified for any duct routed through or terminating in a hazardous zone.
BP Australia — around 1,400 sites
BP operates around 1,400 sites in Australia. After divesting the Kwinana refinery in 2021, BP is now a pure importer-marketer in the liquid-fuels segment. The convenience banner is Reddy Cafe, currently transitioning across the network. BP Pulse is the EV fast-charging arm, with public 150–350 kW chargers being rolled out at a growing subset of metro sites. From a duct contractor perspective, BP's national specification favours fully sealed Class C ductwork to AS 4254.2, with all rectangular joints sealed with low-VOC sealant and round duct joints lapped and machine-formed to TDF or slip-coupling standard. Reddy Cafe kitchen hoods are specified to AS 1668.1 and require stainless internal lining on grease-laden exhaust runs.
Shell Coles Express — Viva Energy (ASX:VEA), around 700 sites
The Shell Coles Express network of around 700 sites is operated under licence by Viva Energy, an ASX-listed integrated refiner-marketer that also owns the Geelong refinery — one of only two operating fuel refineries in Australia, alongside Ampol Lytton's transitioning operation. The Coles Group retail tenancy was bought out by Viva Energy in 2023, bringing the convenience side fully in-house. Site HVAC specifications follow Shell's global retail standard plus the Australian regulatory overlay. Viva also operates Reddy Express on selected sites. For HVAC contractors, a Coles Express refresh typically targets 23 °C interior set point, NC-40, and galvanised supply with insulated returns. The Shell forecourt design routinely uses an enclosed-roof canopy variant that requires mechanical extraction over the dispenser island — a less common feature in the Australian network and one that triggers Ex-rated duct and fan specification under AS/NZS 60079.10.1.
7-Eleven Australia — around 700 sites
7-Eleven Australia, now owned by the Withers Group following acquisition from Seven & i Holdings, operates around 700 forecourt-and-convenience sites with a strong presence in metropolitan New South Wales, Victoria, Queensland and Western Australia. The format has historically led the Australian market on convenience-first retail design, with a high-traffic store, large coffee programme and food-to-go offering. HVAC ductwork on a 7-Eleven site is typically galvanised mild steel to AS/NZS 4254, with a packaged rooftop unit feeding a ceiling supply network and a low-level return path through ceiling-mounted return grilles. Toilet exhaust runs are commonly stainless steel internal and discharge above the canopy line.
EG Group Australia — around 700 sites
EG Group Australia is the rebranded former Woolworths Petrol network, acquired by United Kingdom-headquartered EG Group in 2019. The network operates around 700 sites across Australia and has been undergoing progressive rebranding and refurbishment under the EG Ampol partnership and the EG Group convenience formats. Ductwork specification on EG sites broadly follows the Ampol national standard given the supply agreement, with site-by-site variation depending on the convenience format being rolled out (full Foodary, smaller Ampol Local, or legacy Woolworths Petrol kiosk).
United Petroleum — around 500 sites
United Petroleum operates around 500 sites nationally, with a strong franchise model and a presence in regional Australia. United's site footprint is typically smaller than the majors, and many sites operate a simpler convenience-store format. HVAC duct contractors working on United Petroleum sites should expect a higher proportion of refurbishment work versus new build, often inside existing tenancy footprints with constrained ceiling voids. Galvanised mild steel to AS/NZS 4254 remains the dominant material specification.
Liberty Oil — around 300 sites
Liberty Oil operates around 300 sites concentrated in regional Australia, with a higher diesel mix reflecting agricultural and transport customer base. Many Liberty sites have larger workshop or service-bay components than metro forecourts, which brings AS 4024 machine-safety considerations and additional hazardous-area mapping where vehicle servicing intersects with fuel storage zones.
OTR On The Run — Peregrine Corporation, around 170 sites
OTR is the convenience banner of Peregrine Corporation, a South Australian family-owned business with around 170 sites concentrated in South Australia and Victoria. OTR is widely regarded as the most aggressive convenience-store format in the Australian forecourt sector, with full quick-service-restaurant integration including Hungry Jack's, Subway, Oporto and Krispy Kreme tenancies on-site, a strong own-brand coffee programme (OTR Coffee), and one of the most advanced EV-charging deployments — Tesla Supercharger sites are co-located on selected OTR forecourts. From a duct contractor perspective, OTR is the most demanding format because the kitchen exhaust and fresh-air loads of a full QSR tenancy stack on top of the convenience-store baseline. New-build OTR sites typically run two independent rooftop air-handling systems — one for the convenience store, one for the QSR tenancy — plus dedicated kitchen exhaust ductwork to AS 1668.1.
Independent and adjacent brands
Beyond the eight largest networks, the Australian forecourt sector includes Puma Energy (around 200 sites, owned by Trafigura), Astron Energy (formerly the small-site Caltex network divested in the rebranding), Night Owl convenience stores (separate format, not always co-located with fuel) and City Convenience formats. The Foodary and Reddy Cafe are Ampol and BP's respective in-house cafe brands rather than separate operators.
Section 2 — The regulatory stack: which codes apply where
The HVAC duct contractor on a service station refurbishment is operating inside a layered regulatory envelope. Understanding which standard applies to which zone of the site is the foundation of a defensible duct schedule. The following stack applies to every Australian service station, in descending order of severity.
AS/NZS 60079 series — Electrical installations in hazardous areas
The AS/NZS 60079 family (adopted from IEC 60079) is the governing code for hazardous-area classification. AS/NZS 60079.10.1 covers explosive gas atmospheres and is the document used to draw Zone 0, Zone 1 and Zone 2 envelopes around fuel dispensers, vent risers, tank fills and LPG cylinder cages. AS/NZS 60079.0 covers general requirements for Ex-rated equipment, while AS/NZS 60079.1 (flameproof enclosures), AS/NZS 60079.2 (pressurised enclosures), AS/NZS 60079.7 (increased safety) and AS/NZS 60079.11 (intrinsic safety) cover the protection methods applied to equipment installed within hazardous zones. For HVAC duct contractors, the practical implication is that any fan motor, control device or sensor located in a Zone 1 or Zone 2 envelope must be Ex-rated to one of those protection methods, and any duct passing through a hazardous zone must be electrically continuous, bonded and earthed to prevent static buildup.
Zone 0 is rarely encountered in retail forecourt design — it is the interior of a fuel tank ullage or a vapor recovery line. Zone 1 occurs inside enclosed LPG cylinder cages and within a tight envelope around vent risers and tanker offload points. Zone 2 covers the most common forecourt situations — a 4.6 m horizontal envelope around each dispenser and 1.2 m vertically, extended by 1.5 m around vent risers, and within 1.5 m of any tanker offload point during delivery.
AS 1940 — Storage and handling of flammable and combustible liquids
AS 1940 is the storage and handling code for petrol, diesel and other flammable liquids. It governs setbacks, bunding, vent riser heights, tank fills and the general layout of the forecourt. For HVAC purposes, AS 1940 establishes the geometric envelopes that AS/NZS 60079.10.1 then classifies as hazardous zones. AS 1940 also specifies separation distances between fuel storage and adjacent buildings — a 3 m setback minimum between any vent riser and any building opening (window, door, intake) is a hard requirement that the HVAC outdoor-air intake placement must respect.
AS 1596 — LPG storage and handling
AS 1596 covers the storage and handling of liquefied petroleum gas, both in bulk tanks and in cylinder cages. For convenience-store forecourts, the most common application is the BBQ-cylinder cage at the front of the store — a steel cage holding 9 kg LPG cylinders for customer exchange. AS 1596 requires that an enclosed cage have mechanical ventilation at a minimum of six air changes per hour, ducted from low level (LPG vapor is heavier than air and pools at floor level), with the exhaust discharge at least 3 m above ground and 3 m from any building opening. The duct material is stainless steel (304 minimum, 316 in coastal environments), continuously bonded and earthed.
NFPA 30A — Code for motor fuel dispensing facilities
NFPA 30A is the US National Fire Protection Association code for motor fuel dispensing and is referenced informally in Australian fuel retail engineering, particularly for site layouts originating from US-headquartered operators or for international fleet-and-fuel customers. NFPA 30A provides a useful cross-check on AS 1940 setback distances and on the Zone 1/Zone 2 envelopes around dispensers. The two codes broadly align — NFPA 30A treats a 4.6 m / 1.2 m envelope around a dispenser as a Class I Division 2 area (equivalent to Zone 2 under the IEC/Australian classification).
AS 1668.1 — Mechanical ventilation in buildings (fire and smoke control)
AS 1668.1 covers the mechanical ventilation systems within buildings, including kitchen exhaust, smoke control, stair pressurisation and zone smoke control. For service station HVAC, AS 1668.1 is the controlling code for any kitchen exhaust hood — the Foodary, Reddy Cafe, OTR QSR or barista coffee station — including hood capture velocity (0.4–0.5 m/s face velocity at the front of the hood), ductwork material (galvanised mild steel for non-grease-laden, black steel or stainless for grease-laden), slope back to the hood (1:50 minimum), cleanout doors at every direction change, and discharge location at least 3 m above any roof level and 3 m horizontal from any intake or building opening.
AS 1668.2 — Mechanical ventilation in buildings (ventilation requirements)
AS 1668.2 is the governing ventilation code for retail and convenience environments. The relevant rates for fuel retail are: retail and convenience store at 5 L/s per person of outdoor air at the design occupant density (which for a typical 200 m² store at one person per 4 m² yields 250 L/s of outdoor air); customer toilets at 25 L/s per WC fixture or 10 air changes per hour, whichever is greater; staff rooms and offices at 10 L/s per person; and food preparation areas at the AS 1668.1 kitchen exhaust rate. For a typical 250 m² Australian forecourt convenience store with toilet, staff room and a small food-preparation area, total fresh-air supply lands in the 800–1,200 L/s range.
AS 4254.2 — Ductwork for air-handling systems in buildings (rectangular and flat-oval)
AS 4254.2 is the Australian rectangular-duct construction standard, equivalent to and harmonised with the SMACNA HVAC Duct Construction Standards in many respects. It specifies sheet-metal gauge by duct dimension and pressure class, reinforcement spacing, joint type (TDF, Pittsburgh seam, snap-lock), and sealant class (Class A, B, C — Class C being the tightest leakage class). Most service-station retail ductwork is specified to Class B leakage with 250 Pa pressure rating.
AS 4254.1 — Ductwork for air-handling systems in buildings (flexible ducts)
AS 4254.1 covers flexible duct for short-run connections from rigid ductwork to grilles and diffusers. Most service-station designs limit flexible duct to 1.5 m maximum length per connection and prohibit use in concealed plenums.
AS 5034 — Electrical installations of EV charging stations
AS 5034 is the Australian standard for electrical installations supplying EV charging equipment. For HVAC duct contractors, AS 5034 is relevant where DC fast chargers are housed under a dedicated charging canopy or inside an MV switchroom — both of which trigger ventilation requirements driven by rectifier waste heat and battery energy storage thermal management.
AS 4564 and AS 4839 — Hydrogen refuelling
AS 4564 (general installation requirements for gas appliances) and AS 4839 (LPG industrial systems — being read across to hydrogen pending dedicated AS hydrogen-refuelling code adoption) together form the current Australian regulatory reference for hydrogen refuelling pilots. Hydrogen pilots are very limited in the current Australian market — fewer than ten public hydrogen refuelling stations operating or planned as of 2026 — but where one is proposed, the duct contractor should expect a much wider hazardous-area envelope (hydrogen ignition energy is around an order of magnitude lower than petrol vapor) and a higher prevalence of stainless steel ductwork.
Section 3 — Convenience store HVAC: the retail heart of the site
The convenience store is where the operator earns most of its retail margin. The HVAC design has to keep customers comfortable, control humidity for refrigeration efficiency, and meet the AS 1668.2 fresh-air rate at the design occupancy, all while minimising the duct footprint inside a tight ceiling void.
Set point and design conditions
Australian fuel retail convenience stores typically target a 22–24 °C interior set point with 50–60 % relative humidity, NC-40 acoustic limit at the customer area, and 50–60 lux background plus higher task lighting at the counter. The summer design condition for most Australian capitals is 32–35 °C ambient with 40–50 % RH; the winter design condition is 5–10 °C with 70 % RH. The HVAC system is sized for the summer peak.
Air handling configuration
The dominant configuration on Australian forecourt convenience stores is a packaged rooftop unit (typically 15–30 kW cooling for a 150–250 m² store) feeding a ceiling-supply ductwork network through square-throw diffusers, with return through a ceiling-mounted return grille connecting to a short return-duct run back to the rooftop unit. Outdoor air is mixed at the rooftop unit through a motorised dampered intake. The advantage of the rooftop unit is rapid installation, minimal ceiling void requirement, and the elimination of a separate plant room — important on small footprints.
Larger sites — full Foodary, OTR with QSR tenancy, multi-bay convenience-and-foodservice combinations — typically run two or three separate rooftop units serving the convenience zone, the foodservice zone, and (where present) the back-of-house. Each zone has its own duct branch, its own thermostat and its own outdoor-air rate.
Ductwork material and construction
For the convenience-store retail zone, galvanised mild steel ductwork to AS/NZS 4254 is the universal material specification. Sheet gauge is selected by duct dimension and pressure class — for a 250 Pa Class B system, typical gauges are 0.6 mm for ducts up to 750 mm, 0.8 mm for 750–1,200 mm, and 1.0 mm for larger sizes. Joints are TDF (Transverse Duct Flange) for rectangular ductwork above 600 mm width, Pittsburgh seam for smaller ducts, and slip-coupling or quick-clamp for round and flat-oval branches. Sealant is a low-VOC water-based duct sealant to Class B leakage.
Insulation
Supply ductwork in conditioned space is typically lined internally with 25 mm acoustic insulation (fibreglass-faced or polyester) for the first 3 m downstream of the rooftop unit to absorb fan noise. Beyond that, supply ductwork is externally wrapped with 50 mm fibreglass blanket and a foil vapor barrier. Return ductwork is generally uninsulated within conditioned space. Outdoor-air intake ductwork between the rooftop unit and the outdoor weatherhood is externally insulated and weatherproofed.
Diffuser and grille selection
Square-throw four-way ceiling diffusers at 600 × 600 mm grid module are the default for convenience-store ceilings. Diffuser throw is sized to achieve a terminal velocity of 0.25 m/s in the customer zone with overlap from adjacent diffusers to avoid stagnant zones. Return grilles are sized to achieve a face velocity below 2 m/s to keep NC-40 acoustic targets.
Section 4 — Cool room and refrigeration ductwork
Every Australian forecourt convenience store has at least one walk-in cool room for drinks and dairy at 2–4 °C, and most have a separate freezer at minus 18 to minus 22 °C for ice cream and frozen meals. The HVAC duct contractor's role intersects with the refrigeration contractor's role here — the refrigeration package itself is typically a turnkey supply (Bohn, Heatcraft, Hussmann, Bitzer condensing units, paired with ceiling-mounted unit coolers) but the air-distribution ducts inside the cool room and any heat-rejection ductwork for adjacent compressor racks are within the HVAC scope.
Cool room internal air distribution
Walk-in cool rooms typically use compact ceiling-mounted air-cooler units (commonly 1.5–3.0 kW cooling capacity) that discharge cold air directly into the room with a short throw — the integrated air-cooler fans provide the air distribution and no separate ductwork is needed inside the cool room itself. For larger combined cool rooms exceeding 50 m³ volume, a short galvanised duct may be run from the air cooler to direct cold air toward the rear of the room. The ductwork is galvanised mild steel with externally applied closed-cell elastomeric insulation, sealed vapor barrier, and continuous condensate drainage to a dedicated condensate line.
Compressor rack heat rejection
The refrigeration condensing units serving the cool room and freezer are typically located on the roof or on a dedicated compressor pad outside the building. Where the condensing units are housed inside an enclosed plant room (rare on Australian forecourts but seen on some legacy BP sites), heat rejection ductwork is required — typically a galvanised duct system extracting 1.0–1.5 m³/s of warm air from the plant room and discharging it above roof level. The duct is uninsulated, galvanised, and sized for a face velocity below 5 m/s to keep fan power reasonable.
Refrigeration line set integration
The refrigeration line set (suction and liquid lines) is typically routed alongside the HVAC ductwork in the ceiling void, and the duct contractor needs to coordinate routing to ensure clearances, support spacing, and adequate access for service. A common site issue is HVAC duct supports being mounted on the same threaded rod as refrigeration line supports, causing line-set damage when the duct vibrates.
Section 5 — Food service exhaust: Foodary, Reddy Cafe, OTR, barista coffee
The food-service component of a service station has expanded dramatically in the past decade. A 2010-vintage Australian service station had a coffee pod machine and a hot-pie oven. A 2026-vintage Ampol Foodary, BP Reddy Cafe or OTR forecourt has an espresso bar with a milk steamer, a hot-food display, a sandwich preparation bench, sometimes a full QSR tenancy with deep-fryers and chargrills. Each of these brings its own ventilation requirement.
Coffee bar exhaust
A barista coffee station — espresso machine, grinder, milk steamer, optional batch brewer — generates steam, milk aerosol and limited heat load. AS 1668.2 calls for 50–100 L/s of outdoor air at the bar plus a localised exhaust hood (typically 200–300 L/s) above the espresso machine to capture milk-steamer plume. The exhaust duct is galvanised mild steel, internally lined with 25 mm acoustic insulation for fan noise control, sloped back to the hood for condensate management, and fitted with a grease filter (even though grease loading is minimal, the filter catches milk-solid carry-over). Discharge is above roof level, 3 m horizontal from any intake.
Hot-food display
A hot-food display (rotisserie pies, hot dogs, sliced pizza) generates significant heat and limited grease. The display itself usually has an integrated exhaust hood and downstream filter cassette; the duct contractor's role is to extend that hood to a roof-mounted exhaust fan via galvanised mild steel ductwork, internally cleanable, with a stainless steel insert through any wall penetration to provide a fire-rated separation. Typical exhaust airflow is 400–800 L/s depending on display size.
Quick-service restaurant tenancy
Where the forecourt includes a full QSR tenancy — Hungry Jack's at OTR, Subway at OTR or Ampol, Oporto, Krispy Kreme — the kitchen exhaust system is a major piece of the HVAC duct package. Capture velocity at the hood face is 0.4–0.5 m/s, exhaust airflow is typically 2,000–4,000 L/s per hood, and the duct material transitions from galvanised mild steel on the makeup-air supply side to either black-painted welded steel or grade 304 stainless steel on the grease-laden exhaust side. Slope is 1:50 back to the hood, cleanout doors are provided at every direction change, and the duct is fire-rated to AS 1668.1 with appropriate fire dampers or fire-rated wraps depending on the routing through fire-rated walls.
Makeup air supply
Every food-service exhaust system needs a makeup-air supply, generally sized at 80–90 % of the exhaust rate (the remaining 10–20 % is drawn from the convenience-store conditioned air, creating a slight negative pressure that keeps cooking odours from migrating into the retail area). The makeup-air supply is galvanised mild steel ductwork, externally insulated, with a tempered-air supply in winter to avoid drafts on staff.
Section 6 — Customer toilet ventilation
AS 1668.2 requires customer toilets to be ventilated at 25 L/s per WC fixture or 10 air changes per hour, whichever is greater. For a typical two-WC customer toilet at a service station with a 12 m³ room volume, that is 50 L/s (two WCs at 25 L/s each) versus 33 L/s (10 ACH on 12 m³ × 3,600 / 3,600), so the WC-fixture rate governs.
Toilet exhaust is run as a separate galvanised duct system, with the duct internally coated or stainless steel internal (corrosion resistance against urine vapor and cleaning chemical aerosol), discharged via a roof-mounted exhaust fan above the canopy or building roofline. Discharge location must be at least 3 m from any outdoor-air intake and 3 m from any building opening. The toilet exhaust fan typically runs continuously during trading hours, with an occupancy-sensor boost mode if specified by the operator.
Supply air to the toilet is drawn from the conditioned convenience-store space via a transfer grille in the toilet door or wall — keeping the toilet at a slight negative pressure to the retail area.
Section 7 — Forecourt canopy: the hazardous-area boundary
The forecourt canopy — the steel roof structure over the dispenser islands — is where the hazardous-area envelope intersects the customer-facing experience. Three scenarios cover the bulk of Australian forecourt designs.
Scenario A: open-sided canopy with natural ventilation
This is the dominant Australian configuration. The canopy is open on all four sides, allowing cross-ventilation to disperse any fuel vapor from spills or dispenser drips. Under AS/NZS 60079.10.1 and NFPA 30A, the Zone 2 hazardous envelope extends 4.6 m horizontally from each dispenser and 1.2 m vertically above ground level, with the area above that envelope and outside the canopy dripline being non-hazardous.
For HVAC contractors, this scenario means no mechanical ventilation is required under the canopy. Any ductwork associated with the convenience store or food service that crosses the canopy must terminate above the 1.2 m vertical envelope or be routed entirely outside the 4.6 m horizontal envelope from any dispenser. Outdoor-air intakes for the convenience store rooftop unit must be located at least 3 m from any vent riser and at least 3 m from any tanker offload point — the latter being a transient Zone 2 area during deliveries.
Scenario B: three-sided canopy (covered service area)
Some legacy Shell and BP sites have a partially enclosed canopy with one side closed for noise abatement or weather protection. This configuration changes the hazardous-area classification — the under-canopy volume can become Zone 1 if natural ventilation is impaired. AS/NZS 60079.10.1 requires a site-specific dispersion assessment, and the typical mitigation is mechanical exhaust ventilation under the canopy at a minimum of 12 air changes per hour, with all ductwork stainless steel, bonded and earthed, and exhaust fans Ex-rated to AS/NZS 60079.7 (increased safety) or AS/NZS 60079.11 (intrinsic safety).
Scenario C: fully enclosed canopy
Fully enclosed canopies are rare in Australian fuel retail but are seen at airport refuelling depots, marine refuelling stations and some military or government facilities. The entire under-canopy volume is treated as Zone 1, requiring continuous mechanical ventilation at 18 air changes per hour minimum, Ex-rated equipment throughout, gas detection at low and high level, and emergency shutdown interlocks. SBKJ's stainless steel duct configuration is the appropriate specification for this scenario.
Section 8 — LPG cylinder cage exhaust
Around 80 % of Australian convenience-store forecourts operate an LPG cylinder exchange service for customers — the standard 9 kg cylinder for BBQs and small heaters. The cylinders are stored in a steel cage at the front of the store, typically holding 20–40 cylinders. AS 1596 classifies an enclosed cage as a Zone 1 hazardous area and requires mechanical exhaust.
Design parameters
Mechanical exhaust at a minimum of six air changes per hour, calculated on the internal cage volume. For a typical 1.5 m × 2.0 m × 2.0 m cage (6 m³ volume), that is 36 m³/h or 10 L/s — a small fan in absolute terms but with strict Ex-rated and material requirements.
Extract is from low level (LPG vapor is heavier than air and pools at floor level), through a stainless steel grille flush with the cage floor or 100 mm above floor level. The duct is stainless steel grade 304 minimum (316 in coastal environments), continuously bonded and earthed via a 6 mm² copper bonding strap to the cage steel, with bolted flanges sealed with a non-conductive gasket but bridged with bonding straps. Fan motor is Ex-rated to AS/NZS 60079.7 (increased safety) or located outside the hazardous zone with the fan inlet inside the zone.
Exhaust discharge is at least 3 m above ground level and at least 3 m horizontally from any building opening, vent riser or HVAC intake. Discharge velocity is sized to avoid downwash — typically 7–10 m/s upward through a vertical stack.
Section 9 — Workshop and mechanical service bay (where present)
Some legacy fuel-retail sites — particularly Liberty Oil regional sites, older BP sites and a subset of independent operators — operate a mechanical service bay alongside the convenience store. The service bay is typically used for tyre fitting, oil changes, light mechanical repairs and pre-purchase vehicle inspections. AS 4024 (safety of machinery) applies to any installed lifting equipment, and AS/NZS 60079.10.1 requires hazardous-area mapping around any vehicle fuel tank, particularly where work is being performed near the tank inlet.
Ventilation requirements
The service bay typically requires 6 air changes per hour mechanical extraction, ducted from low level (engine exhaust gases and fuel vapor pool low), discharged above the building roofline. The duct material is galvanised mild steel for the general bay extract and stainless steel for any localised extract over a workbench or paint-mixing station. Vehicle exhaust extraction (tailpipe hoses connected to a flexible-duct system) is typically a separate stainless or aluminium flexible-duct package with a dedicated extraction fan.
Section 10 — Vapor recovery: Stage 1 and Stage 2
Vapor recovery is the capture and return of fuel vapor displaced during fuel handling, to reduce hydrocarbon emissions and customer-facing odours. Two stages are defined.
Stage 1 — Truck-to-tank
Stage 1 vapor recovery captures vapor displaced from the underground storage tank as fuel is offloaded from a delivery tanker, and routes that vapor back into the tanker compartment being unloaded. The system is a closed loop between the tank and the tanker, with no HVAC duct involvement. Stage 1 is mandatory across Australia under EPA regulations in most jurisdictions for tanks above a threshold volume — typically 4,000 L underground tank capacity.
Stage 2 — Nozzle-to-vehicle
Stage 2 vapor recovery captures vapor displaced from the vehicle fuel tank as fuel is dispensed into the tank, and routes that vapor back through the dispenser hose and nozzle into the underground storage tank. Stage 2 is mandated in some Australian jurisdictions (particularly Victoria and parts of New South Wales) for high-throughput sites in densely populated areas. Like Stage 1, Stage 2 is a closed loop and does not involve separate HVAC ducting. The dispenser internal architecture handles the vapor routing through a coaxial hose and a dedicated vapor pump.
For the HVAC duct contractor, the practical implication of vapor recovery is that the volume of fuel vapor escaping into the forecourt atmosphere is significantly reduced, which can in some site-specific risk assessments allow a slight reduction in the hazardous-area envelope. The default Zone 2 envelope around dispensers should still be applied unless a site-specific dispersion study supports a reduction.
Section 11 — EV charging integration
The Australian fuel retail majors are rolling out DC fast charging across their networks. The HVAC duct contractor on a service-station refurbishment is increasingly being asked to integrate cooling and ventilation for charger cabinets, dedicated charging canopies and adjacent battery energy storage systems.
Charger waste heat
A 50 kW DC fast charger operating at full load dissipates around 4–6 kW of waste heat through the internal AC-DC rectifier and cooling fans; a 150 kW unit dissipates 12–18 kW; a 350 kW unit dissipates 28–42 kW. Charger cabinets are typically rated for outdoor operation with integrated cooling, but where multiple chargers are housed under a dedicated charging canopy with limited natural ventilation, supplementary forced ventilation is required.
Typical specification is 50–100 L/s of forced ventilation per 50 kW of charger capacity, ducted from low level (cool intake) and discharged at high level (warm exhaust). The duct is galvanised mild steel — no hazardous-area classification applies because there is no fuel vapor in the EV charging zone. Fan motors are standard (non-Ex-rated). The duct is sized for a face velocity below 5 m/s for acoustic compliance under the canopy.
Battery energy storage system
Where the site includes a battery energy storage system (BESS) — typically 100–500 kWh storage co-located with the DC fast chargers to manage grid demand peaks — the BESS cabinet requires a dedicated ventilation path with thermal management to AS 5034 and the OEM specification. Lithium-ion BESS cabinets are most commonly housed in an outdoor enclosure with integrated cooling, but where the BESS is housed inside an MV switchroom, dedicated room ventilation is required, plus gas detection for lithium thermal runaway off-gassing. SBKJ has covered this in detail in the EV charging and BESS HVAC duct guide.
Operator-specific notes
Ampol AmpCharge is rolling out a standardised 75–150 kW DC fast-charging format across selected metro and highway sites. BP Pulse is rolling out 150–350 kW chargers, with the higher power tier requiring more substantial ventilation and BESS integration. Tesla Supercharger is co-located on selected OTR forecourts, with Tesla supplying the chargers, cabinets and ventilation specification as a turnkey package — the duct contractor's role on a Tesla Supercharger build is typically limited to the convenience-store HVAC, with Tesla's contractor handling the charger-zone ventilation.
Section 12 — Hydrogen refuelling: the future, in pilot
Hydrogen refuelling is in very early pilot stage in Australia. Fewer than ten public hydrogen refuelling stations are operating or planned as of 2026, primarily serving fleet customers (buses, heavy trucks). The Coregas, Viva Energy, BP and Ampol pilots all reference AS 4564 (gas appliance installation) and AS 4839 (LPG industrial systems, read across to hydrogen), pending dedicated Australian hydrogen-refuelling code adoption.
From an HVAC duct perspective, hydrogen refuelling introduces three new considerations. First, the hazardous-area envelope is wider — hydrogen ignition energy is around one order of magnitude lower than petrol vapor, and the envelope can extend 6–8 m horizontally from a dispenser versus the 4.6 m petrol envelope. Second, hydrogen is lighter than air and pools at the highest point of any enclosed space — opposite to LPG which pools at the lowest point. Any enclosed hydrogen dispensing area requires extract from the highest point of the space, not the lowest. Third, the duct material is exclusively stainless steel (grade 316 preferred for hydrogen embrittlement resistance), with all welded joints (no mechanical joints permitted in hazardous zones), and continuous bonding and earthing throughout.
For deeper coverage, see the hydrogen production HVAC duct guide.
Section 13 — Material specification by zone
Galvanised mild steel to AS/NZS 1397 (Z275 coating) is the dominant material for all non-hazardous zones — convenience store supply and return, customer toilet exhaust (with internal stainless lining or coating), food-service supply, makeup air, EV charging supply and exhaust, workshop general extract, and any duct passing through but not terminating in a hazardous area. Sheet gauges follow AS 4254.2, joints are TDF, Pittsburgh seam or slip-coupling, sealant is Class B to Class C. Stainless steel grade 304 (general) or grade 316 (coastal, chloride-exposed) is specified for LPG cylinder cage exhaust, partially or fully enclosed forecourt canopy exhaust, grease-laden food-service exhaust, toilet exhaust internal lining, and any duct terminating within a Zone 1 hazardous area. Black-painted welded mild steel is an alternative to stainless for kitchen grease exhaust on certain BP Reddy Cafe and OTR specifications — heavier-gauge, fire-rated, with continuous welded joints. Closed-cell elastomeric foam insulation (Armaflex or equivalent) at 19–25 mm is specified for any duct exposed to chilled air below ambient dew point — cool room internal distribution, chilled-water duct in coastal humid climates, condensate-bearing runs. The vapor barrier must be continuous; any breach allows condensation within the insulation and rapidly degrades thermal performance.
Section 14 — SBKJ machine configuration for fuel retail ductwork
The HVAC duct fabricator supplying the Australian fuel retail sector typically needs three production capabilities: a high-volume galvanised mild steel auto duct line for bulk retail work, a stainless capability for hazardous-area exhaust and food-service stainless, and a round and flat-oval tubeformer for spiral-duct work (rare in fuel retail but specified on certain Shell Coles Express and premium Foodary sites). The SBAL-III is SBKJ's auto duct production line, designed for galvanised mild steel coil 0.5–1.5 mm thickness, coil width up to 1,500 mm, producing rectangular ductwork to AS/NZS 4254.2, SMACNA and EN 1505. Single-shift output on typical fuel-retail spec is 600–900 m of finished duct. SBKJ supplies the SBAL-III with a stainless steel coil-feed and tooling configuration that allows the same machine to switch between galvanised and stainless 304 or 316 production with a tooling changeover — for a fuel-retail fabricator running mostly galvanised with occasional stainless runs for the LPG cage, canopy exhaust and grease exhaust, the single-machine dual-material capability is the most cost-effective production setup. Where round or flat-oval ductwork is specified, SBKJ supplies a spiral tubeformer rated to galvanised and stainless coil, 8–12 m/min depending on diameter, with diameters from 80 mm to 2,000 mm covered by a single machine with tooling change. For accessory work the SBKJ Stitchwelder produces continuous welded longitudinal seams, the Bending Machine produces precision transition pieces, and the Gorelocker produces the rolled-and-locked seam common on round and flat-oval accessories.
Section 15 — Project workflow on an Australian fuel retail refurbishment
The typical refurbishment of an Australian service station — Ampol Foodary rebuild, BP Reddy Cafe rollout, OTR new build, 7-Eleven format refresh — runs to a fixed-week construction programme with the site closed during the works. Weeks 1–2: strip-out and survey — existing ductwork is removed, the ceiling void surveyed for clashes with new structure, refrigeration line-set routing and electrical containment, and any field clashes flagged before fabrication. Weeks 3–4: fabrication — ductwork is fabricated to AS 4254.2 in the contractor's workshop on an auto duct line (typically an SBAL-III or equivalent) with TDF joints, Pittsburgh seams, slip-couplings and stainless transition pieces for hazardous-area terminations. Weeks 5–6: installation — ductwork installed in sequence with the ceiling, electrical containment and refrigeration line-sets, with joint sealing per section and leakage testing where Class C is required. Week 7: commissioning — rooftop units energised, airflow measured against the design schedule, diffusers and grilles adjusted, kitchen exhaust tested for hood-face velocity, LPG cage exhaust tested and Ex-rated certification verified. Week 8: handover and trading — commissioning report, duct schedule, as-built drawings and Ex-rated certification dossier handed over, site reopens for trading on the planned Friday or Saturday morning.
Section 16 — Cost and timeline benchmarks
For budgetary purposes, the HVAC ductwork package on a typical Australian service-station refurbishment falls in the following ranges in 2026 currency, exclusive of plant (rooftop units, refrigeration condensing units, fans).
- Small format (150 m² store, basic coffee bar) — duct package fabricated and installed at around AUD 35,000–55,000, 3–4 week installation.
- Medium format (200–250 m² with Foodary or Reddy Cafe) — AUD 60,000–95,000, 4–6 week installation.
- Large format (250–400 m² with full QSR tenancy, OTR-style) — AUD 100,000–180,000, 6–8 week installation with a higher proportion of stainless exhaust.
- EV charging-only standalone hub (4–8 chargers under a dedicated canopy) — AUD 25,000–50,000, primarily galvanised mild steel for charger and BESS room ventilation.
Section 17 — Common pitfalls in fuel retail HVAC duct contracting
- Outdoor-air intake too close to a vent riser. AS 1940 requires 3 m separation between a fuel vent riser and any building opening, including HVAC intakes. Verify vent riser positions at design stage.
- LPG cage exhaust ducted with galvanised steel. The LPG cylinder cage is a Zone 1 hazardous area under AS 1596 and AS/NZS 60079.10.1 — galvanised mild steel is not acceptable. Stainless steel (304 or 316), bonded and earthed continuously, is mandatory.
- Kitchen exhaust slope reversed. AS 1668.1 requires 1:50 minimum slope back to the hood. Reverse slope creates a pool of grease and condensate at the low point — a fire risk and cleaning hazard.
- Forecourt canopy exhaust without Ex-rated fan. Three-sided or fully enclosed canopies requiring mechanical exhaust need fans Ex-rated to AS/NZS 60079.7 or 60079.11. Standard non-Ex-rated fans in hazardous zones are a major non-conformance.
- Bonding strap missing on stainless steel hazardous-area duct. Bolted flanges with non-conductive gaskets must be bridged with a 6 mm² copper bonding strap to prevent static ignition. A common audit finding.
- Class C leakage spec on Class B sealant. Class C requires a specific sealant product and application technique. Specify at design stage and verify during installation.
- Refrigeration line set sharing a hanger with HVAC duct. Vibration transmission damages line-set insulation. Always specify independent hangers with a minimum 100 mm separation.
Section 18 — Operator-specific quirks the field has taught us
Each major Australian fuel retail operator has site-specific design quirks not always written into the national specification but enforced at handover. Ampol Foodary enforces a 23 °C set point with NC-35 in the seating area, a 250 L/s minimum coffee-bar exhaust, and stainless 316 mandatory on the LPG cage exhaust. BP Reddy Cafe requires TDF joints above 600 mm width, low-VOC water-based sealant, stainless internal lining on toilet exhaust, and welded mild steel or stainless on kitchen grease duct. Shell Coles Express (Viva Energy) calls for fully sealed Class C with leakage testing on every supply run and discharge stacks 1 m above any roof obstruction. 7-Eleven Australia uses a tight standard kit-of-parts with the rooftop unit positioned over the store interior, not the canopy, to minimise vapor-contamination risk on intake. EG Group Australia follows the Ampol national standard on Ampol-branded sites and a separate EG Group spec on EG-branded sites — clarification is essential where the site is mid-rebranding. United Petroleum is value-conscious — galvanised throughout where compliant, minimum stainless content, single rooftop unit. Liberty Oil regional bias means a higher proportion of sites with workshop bays attached, extending the HVAC scope to workshop ventilation and vehicle exhaust extraction. OTR On The Run is the most demanding operator — full QSR tenancy, dual rooftop units, Tesla Supercharger zone ventilation, dedicated OTR Coffee extract, and stainless content of 25–35 % of total duct length.
Section 19 — Future-proofing and SBKJ support
The Australian forecourt is on a 10–15 year transition from pure liquid-fuel retail to a multi-energy destination. EV charging will install on a growing subset of sites through 2026–2030, and the HVAC duct package on a new-build forecourt should include provision for future charger-zone ventilation — a stub-up for additional supply and exhaust runs, with sized cable trays and ductwork space reserved. Hydrogen pilots may scale subject to fleet adoption; the duct contractor should design the convenience-store HVAC with a 5 m clearance from any planned hydrogen-dispensing zone to allow future buildout without retrofit disruption. BESS integration will become more common as DC fast charging scales and grid-connection constraints push operators toward on-site storage.
SBKJ Group supplies HVAC duct production machinery to fabrication contractors and in-house operator workshops across the Australian fuel retail sector. Our SBAL-III auto duct line is the bulk-production workhorse for galvanised mild steel ductwork, with a stainless steel coil-feed configuration available for the hazardous-area and food-service runs that sit alongside the dominant galvanised content. The Stitchwelder, Bending Machine and Gorelocker handle the accessory work — longitudinal welded seams, precision transition pieces, round and flat-oval seam work. SBKJ is headquartered in Box Hill North, Victoria, with engineering support in Australian business hours and a 12-hour reply guarantee on technical questions.
Section 20 — Putting it all together
An Australian service station is one of the most regulated small-footprint built environments in the country. The HVAC duct contractor needs to operate fluently in five overlapping codes — AS 1668.2 for ventilation, AS/NZS 60079 for hazardous areas, AS 1940 for flammable liquids, AS 1596 for LPG, AS 5034 for EV charging — across seven zones: convenience store, customer toilet, cool room, food service, forecourt canopy, LPG cage and EV charging. The duct schedule is multi-material — predominantly galvanised mild steel for bulk retail, stainless for hazardous and grease-laden exhaust, with localised black-painted welded steel and closed-cell elastomeric insulation. Get this right and the refurbishment closes on time, the site reopens on the planned Friday or Saturday, the operator earns weekend trade. The cost of doing the duct schedule properly is one engineer-week. The cost of getting it wrong is six figures of opportunity cost.
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FAQ
What ventilation rate does a convenience store at a service station require under AS 1668.2?
AS 1668.2 classifies a convenience store as retail and requires 5 L/s per person of outdoor air at the design occupant density. A 200 m² store at one person per 4 m² needs around 250 L/s of fresh air, with customer toilets adding 25 L/s per WC. Total fresh-air supply on a typical Australian forecourt store lands in the 800–1,200 L/s range.
Are forecourt canopies treated as hazardous areas under AS/NZS 60079?
An open-sided canopy with natural ventilation is normally Zone 2 within 4.6 m horizontal and 1.2 m vertical of each dispenser, with non-hazardous area above and outside. Enclosed or three-sided canopies can become Zone 1 and require mechanical extract and Ex-rated equipment.
What material should ductwork be made from in an LPG cage?
Stainless steel grade 304 or 316 mandatory, continuously bonded and earthed, with the fan motor Ex-rated to AS/NZS 60079.7 or located outside the hazardous zone. Galvanised mild steel is not acceptable in a Zone 1 LPG cage.
How does EV charging integration change HVAC design at a forecourt?
DC fast chargers at 50–350 kW dissipate 4–42 kW of waste heat each, requiring 50–100 L/s of forced ventilation per 50 kW of charger capacity under any enclosed charging canopy. The ductwork is non-hazardous galvanised mild steel because there is no fuel vapor in the EV zone.
Which Australian fuel retailers buy the most ductwork each year?
The eight largest networks by site count are Ampol (~1,900), BP (~1,400), Shell Coles Express via Viva Energy (~700), 7-Eleven Australia (~700), EG Group Australia (~700), United Petroleum (~500), Liberty Oil (~300) and OTR On The Run (~170). Refurbishment activity is currently elevated across Ampol Foodary, BP Reddy Cafe and OTR new build.
