Why storage HVAC is its own engineering discipline
HVAC engineering for wine and spirits production — fermenters, mash tuns, distillation, bottling halls — is well covered in the trade literature, and we have written a separate companion piece on it (see the cross-link to Brewing, Distilling & Winery HVAC Duct Guide). What is less well covered, and what this guide deliberately concentrates on, is the storage side of the same supply chain. Once the wine is bottled and labelled, or once the new-make spirit is filled into oak, the equation changes completely. Production HVAC is about removing process loads — yeast heat, CIP steam, fermentation CO2, distillation latent heat. Storage HVAC is about doing very nearly nothing for a very long time, and doing it without a single ten-day excursion that reverses years of careful maturation.
The difference shows up in the brief. A brewery wants air changes, exhaust capture and process tolerance. A wine archive wants stillness — temperature within plus or minus one degree, humidity within plus or minus five percent, vibration below 0.1 g, and complete darkness — held for a decade. A bonded spirits maturation hall wants the third thing entirely: enough ventilation to dilute the angels share evaporating from oak, enough security to satisfy the Australian Taxation Office that nothing is leaving without duty paid, and enough thermal control that maturation does not run away in the warmer states. Three different rooms, three different HVAC briefs, three different duct material specifications, and one machine line that has to make all the duct.
This guide is written for facility engineers, MEP consultants, project managers and bonded warehouse operators planning new build, expansion or refurbishment of wine and spirits storage in Australia. It is also written for HVAC fabricators sizing their machine purchase against the projects they expect to win in the next decade. SBKJ engineers walk through this exact framework with our customers, and we use it ourselves to specify the SBAL-V, SBAL-III and spiral tubeformer machines that actually produce the duct. Cross-links to our companion guides are at the end.
The wine cellar climate window — the numbers and why they matter
If you ask three sommeliers, two cellar masters and a fine-wine merchant for the ideal cellaring conditions you will get six slightly different answers, but the consensus window in the technical literature has been stable for thirty years. Long-term cellaring of fine wine — meaning bottles intended to be drunk in five to fifty years rather than within twelve months of release — is best held at 13 to 15 degrees Celsius, with the cellar held within plus or minus one degree of whatever set point inside that window the operator chooses. Relative humidity is held at 70 percent, plus or minus five percent. Light is held to near zero, with any working light sources free of ultraviolet emission. Vibration is held below 0.1 g, which means rotating plant has to be acoustically and structurally isolated from the cellar envelope. Air movement is the minimum required to maintain temperature uniformity — typically one to two air changes per hour, against the four ACH minimum we will set for spirits maturation later in the guide.
The reason these numbers are non-negotiable, and the reason the industry literature is so uniform, is that wine ages best when the chemistry runs slowly and steadily. Higher temperatures accelerate ester development, tannin polymerisation and oxidation reactions, but unevenly across compounds, so a wine held at 18 degrees ages differently to a wine held at 13 degrees — not just faster. Temperature swings drive expansion and contraction of the wine in the bottle, which pushes against and pulls back from the cork, eventually causing seepage and oxidation. A cellar held steady at 15 degrees year-round will outperform a cellar that swings from 11 in winter to 17 in summer, even though the average is the same. Stability is the master variable.
Humidity matters because corks dry out and shrink at low RH, allowing oxygen ingress around the seal, and at high RH labels mould and capsules corrode. Seventy percent is the target because below 50 percent the cork risks shrinkage in a few years, and above 80 percent label and capsule damage starts within months. The five-percent tolerance band reflects practical engineering realities — controlling humidity inside a five-percent window is achievable with a properly sized refrigerant DX or chilled-water coil and a reheat or sensible cooling strategy. Tightening the window further increases plant cost and complexity faster than it improves outcomes.
Vibration is included in the brief because dissolved CO2 and aroma compounds in wine are sensitive to mechanical agitation over long timescales. Premium cellars therefore isolate plant rooms from the storage volume with structural breaks and resilient mounts. From an HVAC point of view this means the air handler is not bolted to a wall shared with the cellar, fan motors are mounted on inertia bases, and supply duct is broken from the air handler with flexible connectors that absorb residual vibration without transmitting it through the duct envelope into the storage room.
Light enters the discussion because UV and visible light degrade flavour and colour compounds in wine, which is why cellars are dark and wine bottles themselves are made of dark glass. The three colours on the bottling line — opaque, amber, and dark green — are all UV blockers. From an HVAC perspective the implication is that any working illumination inside the cellar must be UV-free. Practical specification: LED with a diffuser and no UV component in the spectrum. Old-style incandescent and most fluorescents are excluded because they emit either UV or sufficient infrared to create local hot spots near the lamp. LEDs also generate far less heat than incandescent, which keeps the sensible load on the cellar plant proportionate to the room rather than disproportionate to the lighting.
Vapor barrier construction — the cellar envelope
The single design detail that separates a cellar that runs cleanly for forty years from one that grows mould inside the wall cavity within five is the continuity of the vapor barrier. A wine cellar is, in thermodynamic terms, a cold humid box surrounded by warm dry building. Without a continuous external vapor barrier the moisture in the cellar air migrates outward through every gap, condenses inside the insulation when it hits the dew point, and stays there. The wall cavity becomes a permanent moist zone, mould blooms, and within a few years the insulation R-value collapses and the structural timber rots. The same risk applies inside duct routing if the insulation system is not engineered properly.
The basic rule is that the vapor barrier sits on the warm side of the insulation. For a cellar inside a warm building, that means the vapor barrier is on the outside of the cellar envelope, wrapped continuously over walls, ceiling and floor, and turned through every duct, pipe and conduit penetration with a sealed boot. Every joint is taped and pressure-tested. Every penetration uses a sleeve with a sealant that does not crack at the cellar dew point. Every supply diffuser frame is set into the vapor barrier with a continuous bead, not just screwed against it.
For supply and return ductwork running inside the cellar envelope the duct is generally treated as part of the cellar volume — the duct surface is at cellar temperature, so condensation on the outside of the duct is not the issue. The issue is duct that crosses the vapor barrier. Where supply duct from a plant room outside the cellar penetrates the cellar envelope, it must be insulated externally and vapor-wrapped continuously from the air handler all the way through the cellar wall, with the wrap sealed to the cellar vapor barrier at the penetration. Anything less and the duct surface inside the wall cavity becomes a condensation collector and a mould nursery.
Insulation thickness on the warm-side run is sized to push the dew point outside the duct wall in the warmest expected ambient. For an Australian context that means design for a 35 to 40 degree summer day with 60 percent ambient RH, supply duct at 11 to 13 degrees, and an insulation R-value that holds the duct outer surface above the ambient dew point. A 50 millimetre rigid mineral wool wrap with a foil-faced vapor barrier is adequate for most cellar applications. Premium archives in regions with extreme summer ambient temperatures use 75 millimetre. Closed-cell foam insulation with an integral vapor barrier is preferred for retrofit applications where access is constrained.
Cool storage adjacent to retail — the bottle shop sub-archive
Not all wine storage is dedicated archive. A meaningful portion of the duct demand in Australia comes from the cool storage rooms attached to retail liquor and bottle shops. These are not primarily for premium ageing — most stock turns within twelve months — but they exist because retail floor space sits at 22 to 24 degrees year-round and direct exposure to retail conditions degrades wine quickly. The cool back-of-house operates at 12 to 14 degrees and 65 to 70 percent RH, somewhere between fine cellaring and ambient.
The major Australian retail liquor groups operate hundreds of these rooms across the country, and the HVAC brief is recognisable across all of them. Endeavour Group operates Dan Murphy's and BWS, with cool back-of-house storage attached to most Dan Murphy's destination stores. Coles Liquor Group operates Liquorland, First Choice Liquor Superstore and Vintage Cellars, with the Vintage Cellars premium boutique format placing greater emphasis on cellar-conditioned storage for higher-margin stock. Independent Liquor Group operates a network of independent retail brands across the country with cellar storage attached to most flagship stores. The HVAC duct demand from this retail tier alone is in the thousands of square metres of supply duct per year, almost entirely galvanised AS 1397 Z275 in rectangular sections.
Cool retail storage is a more forgiving HVAC brief than fine cellaring. Stock turns quickly enough that the absolute humidity tolerance is wider — 65 to 75 percent is acceptable, plus or minus seven percent rather than five. Vibration tolerance is wider because the wine is not held long enough for vibration effects to develop. Lighting tolerances are wider because operating staff need adequate working light and dwell time is short. The constants are temperature stability, vapor barrier continuity, and clean dust-free duct construction so that the retail stock is not contaminated with construction debris or fibre shedding from cheap acoustic linings.
The major Australian cellars and what they teach about HVAC briefs
The named premium cellars in Australia each have a specific HVAC story worth understanding before designing a similar facility. Penfolds operates two flagship cellars worth knowing about. The Magill Estate cellar in South Australia, attached to the original Penfolds vineyard in Adelaide's eastern suburbs, holds heritage stock and the oldest reserves in the Penfolds library. The HVAC engineering for Magill prioritises stability over absolute precision — the heritage cellar is partially below grade, which moderates seasonal swing naturally, and the mechanical plant is sized to trim rather than carry the full thermal load. The Nuriootpa cellar, in the Barossa Valley, is the working facility behind much of the Penfolds production stock and operates at higher throughput, with HVAC sized accordingly.
Treasury Wine Estates operates a network of cellars associated with the Penfolds, Wolf Blass, Wynns, Lindemans and other portfolio brands across the Barossa, Coonawarra and other regions. Accolade Wines operates the Berri Estates facility in South Australia, the largest single wine production and storage facility in Australia by volume. Pernod Ricard Winemakers operates the Rowland Flat facility in the Barossa, home of the Jacob's Creek brand, and a substantial cellar capacity. Brown Brothers operates the Milawa heritage cellar in northeast Victoria, a working historic cellar that has been in continuous operation since the late nineteenth century and serves as both production and tourism asset.
What these facilities have in common as HVAC briefs is that they are bigger than most architects expect, geographically distributed, and built incrementally over decades — meaning the duct material specification has to remain consistent across additions made twenty years apart. Galvanised AS 1397 Z275 with sealed-seam Class A construction is the consistent specification because it ages well at cellar conditions, is widely available, and matches across decades of build. The exception is the heritage display cellar areas where painted or epoxy-coated coil is sometimes specified for visual reasons.
What these facilities also share is that the HVAC duct is rarely the glamour item on the project brief. The cellars are talked about in terms of oak, fermentation, vintage and brand. The duct is talked about — when it is talked about at all — in terms of whether it stays out of sight, stays at temperature and stays out of the way of the working crew. This is a useful brief discipline. Storage cellar duct should be invisible, silent, dimensionally accurate to the architectural setout, and durable enough that the next generation of operators inherits it functioning rather than failing.
Spirits storage — the bonded warehouse and the angels share
Switching from wine archives to bonded spirits warehousing changes the HVAC brief from minimum air movement to controlled ventilation. Spirits in barrel, and to a lesser extent spirits in glass at the case-storage stage, give off ethanol vapor continuously. The industry term for the loss is the angels share — the proportion of liquid that evaporates through the oak during maturation. In Australian conditions a typical spirit barrel loses two to four percent per year, mostly water in cooler stores and disproportionately ethanol in warmer stores. Every percent that leaves the barrel ends up as vapor in the warehouse atmosphere.
The vapor has three operational consequences. The first is dilution and ventilation — the warehouse atmosphere has to be kept well below the lower flammable limit for ethanol, which is around 3.3 percent by volume. In practice this means a maturation hall is engineered for a minimum of four air changes per hour of fresh air supply with matched mechanical exhaust, and ignition sources are excluded or rated appropriately. Four ACH is the floor — premium maturation halls run six to eight ACH because the higher rate also helps even out temperature stratification across stacked barrels. The second consequence is corrosion — ethanol vapor at storage concentrations attacks galvanised zinc coatings over time, particularly in seam and joint areas. The third consequence is fire detection. Aspirating smoke detection at high sensitivity is the industry standard because conventional point detectors are slow to respond in a room with significant vapor and forced ventilation.
Material selection for spirits warehouse ductwork therefore differs from a wine cellar. Galvanised AS 1397 Z275 is acceptable for fresh-air supply runs that are not in the vapor zone — the supply air enters the warehouse clean. The exhaust runs that draw the vapor-laden warehouse air are the corrosion-exposed runs and are best specified in 304 stainless steel. For projects where 304 stainless across the full exhaust system exceeds budget, the practical compromise is 304 stainless for the first five to ten metres downstream of any exhaust grille and for the discharge stack, with high-build epoxy-coated galvanised on the intermediate runs. SBKJ machines support both galvanised and stainless coil with the same line, so the bill of duct can be split between two material grades on one tooling setup.
Australian spirit producers and what their stores look like
Australia's craft and premium spirits sector has grown substantially over the last fifteen years and the bonded storage requirement has grown with it. Tasmania is the centre of Australian whisky production and storage. Lark Distillery in Hobart is widely regarded as the founding distillery of the modern Tasmanian whisky industry, with maturation stores spread across multiple sites. Sullivans Cove, also Tasmanian, has been a force in international whisky competition for two decades and operates maturation stores aligned with that profile. Overeem operates from southern Tasmania with bourbon and sherry cask maturation. Hellyers Road is on the northwest Tasmanian coast and operates one of the larger Tasmanian distilleries by volume, with substantial bonded warehouse capacity. Belgrove Distillery operates in the Tasmanian midlands as a small-batch rye specialist with on-site maturation.
On the mainland, Archie Rose Distilling Co. operates from Sydney with one of the more architecturally polished urban distilleries in the country and significant bonded storage attached. Starward Distillery operates from Melbourne and has built a substantial export profile in Australian whisky aged in red wine barrels — a profile that requires careful storage temperature control because the residual wine in the barrel interacts with the maturing spirit. Four Pillars Gin operates from Healesville in the Yarra Valley, and while gin is not aged in cask in the same manner as whisky, the bonded storage of bottled stock under excise control is operationally similar. Australian Distilling Company operates Ned and Vodka O brands with bonded storage capacity in Adelaide and elsewhere.
Across these producers the HVAC brief for the maturation halls is consistent in principle and varies in scale. Tasmania benefits from naturally cooler ambient conditions which moderates the angels share and softens the cooling load. Mainland producers in warmer climates require more aggressive thermal control and ventilation. The duct demand from the sector as a whole is in the thousands of square metres per year, with a higher proportion of stainless and coated specifications than the wine sector reflects.
Bonded warehousing — Australian regulatory framework
A bonded warehouse storing excisable wine and spirits in Australia operates under a layered regulatory framework that is worth understanding before HVAC design begins, because some of the controls have direct duct and zoning implications. The primary statutes are the Excise Act 1901, which governs domestically produced excisable goods, and the Customs Act 1901, which governs imported goods held under customs control. Both statutes define the conditions under which excisable goods can be held in a licensed warehouse with duty assessment deferred until the goods are released for home consumption.
Wine equalisation tax is administered separately from excise on spirits, but the warehousing principle is parallel — duty is assessed at release, the warehouse is the holding point, and the operator is licensed and accountable. Spirits attract excise duty at rates set by the Australian Taxation Office and indexed periodically. Imported spirits attract customs duty in addition where applicable. The licensing terms require the warehouse to be physically secure against unauthorised removal, with controlled access points, monitored stock movements, accurate inventory at all times, and audit trails that can be reconciled by ATO officers on inspection.
State liquor licensing operates as an additional layer over the federal excise framework. Each state has its own licensing regime governing the wholesale and retail handling of liquor — for example the relevant authorities in Victoria, New South Wales, Queensland, South Australia, Western Australia, Tasmania, the Northern Territory and the Australian Capital Territory each issue their own licences and impose their own conditions. A bonded warehouse in any state therefore operates under both the federal excise framework and the relevant state licence simultaneously. From an HVAC perspective the practical consequence is that the building's mechanical and electrical layout has to support the federal compartmentalisation requirements without creating openings or ducted paths that could be construed as breaches of physical security.
Specifically, the bonded zone of a warehouse is the area inside which excisable goods are held with duty deferred. The unbonded zone is the area outside that compartmentalisation, where goods are either pre-bond or post-release. HVAC ductwork that passes through the bonded boundary has to be sized, sealed and detailed so that it does not provide a covert removal path. In practice this means duct penetrations through the bonded boundary are constructed with security mesh inside the duct at the penetration plane, with the mesh detail signed off as part of the warehouse licensing application. Air handlers and major plant items are located outside the bonded zone where possible, with the bonded zone served only by ducts and grilles.
3PL and distribution — the bonded liquor supply chain
The third-party logistics tier sits between producers and retailers and is the largest single source of bonded warehouse duct demand in Australia. Major 3PL providers operating bonded liquor capacity include DHL Supply Chain with bonded facilities in several capitals, Toll Group with extensive warehousing operations across the country, and Linfox with national coverage including bonded sites adjacent to major distribution corridors. Endeavour Group operates internal bonded distribution alongside its Dan Murphy's and BWS retail network. Independent Liquor Group operates a national distribution network supporting independent retail brands. MyDeal Liquor and similar online retailers operate or contract bonded fulfilment to support direct-to-consumer dispatch.
The HVAC brief for a bonded distribution warehouse is closer to general dry warehousing than to fine cellar conditioning. Targets are 18 to 22 degrees ambient with stability of plus or minus three degrees, humidity moderated to prevent label damage but not actively controlled, ventilation at AS 1668.2 minimums for occupied warehouse with a margin to dilute any spirits vapor at the case-pick face, and lighting at general warehouse levels with provision for video surveillance sufficient for the bonded inventory audit. The duct material is almost universally galvanised AS 1397 Z275 in rectangular sections, with diameters and quantities driven by the building footprint rather than by special storage conditions. SBKJ SBAL-V production lines configured for that coil specification are exactly the right machine class for the duct fabricator who supplies into this segment.
Where the brief becomes more demanding is in any sub-zone of the warehouse dedicated to premium stock, allocated wines, or temperature-sensitive imports. These sub-zones often have a dedicated HVAC system inside the larger building, typically a chilled-water plant with insulated supply ductwork and tighter humidity control. The duct construction in these sub-zones is rectangular galvanised with vapor wrap on supply runs, and the fabrication is straightforward for an SBKJ SBAL-V or SBAL-III line.
Heat load from light fixtures — LED only, no UV
Lighting load is a small absolute number in any cellar but a high-leverage one because the lighting choice doubles as a wine-protection choice. Incandescent lighting is excluded because it generates significant infrared heat, creates local hot spots near bottles, and includes a low-level ultraviolet component that degrades wine over time. Most fluorescent lighting is excluded because it emits low-level UV, even when filtered, and because the failure mode of fluorescent tubes — flicker and end-of-life UV spike — is hard to monitor in low-occupancy storage. Compact fluorescent lamps are excluded for the same reasons.
LED lighting is the only acceptable specification for any modern cellar. LEDs emit no UV, run cool enough that the heat load is negligible, are dimmable for circulation versus working light scenarios, and have lifetimes long enough that maintenance access into the cellar is rare. The recommended specification is 3000 to 3500 K colour temperature for warm white that flatters bottle labels, with a colour rendering index above 80 for accurate label inspection, mounted in sealed fixtures rated for cellar humidity. A typical fine cellar runs at 20 to 50 lux of working light when occupied, dropping to under 5 lux or to zero when unoccupied, controlled by occupancy sensors integrated with the security system.
For the HVAC sizing calculation the lighting heat load is so low — typically under 5 W per square metre — that it falls within the rounding margin of the cellar plant calculation. The structural heat gain through the envelope and the latent load from any moisture migration dominate the calculation entirely. This is one of the few HVAC briefs where the lighting can effectively be neglected for plant sizing, which is the opposite of a typical commercial building where lighting is the largest internal load.
Sprinkler integration without thermal bridging
Cellars and bonded warehouses are sprinklered the same as any other commercial building under AS 2118, with the practical complication that sprinkler pipe is metal and metal at warm building temperature is a thermal bridge into the cool cellar. A sprinkler main running unprotected through the cellar envelope is a permanent cold spot on the cellar surface — condensation collects on the pipe inside the wall cavity, drips onto whatever is below, and over years stains floors, damages bottles and breeds mould.
The detail that solves this is a thermal break sleeve at the cellar penetration. The sprinkler pipe enters the cellar through a sleeve insulated to the same R-value as the surrounding wall, with the insulation continuous through the sleeve and a vapor barrier sealed around the pipe at the warm side. Inside the cellar the sprinkler pipe sits at cellar temperature, so condensation on its surface is not an issue. Outside the cellar the pipe is warm and dry. The sleeve is the transition zone that prevents the warm-side pipe surface from cooling to the cellar dew point.
Practical specification for the sleeve is 50 to 75 millimetre rigid foam insulation around the pipe with an aluminium foil vapor wrap, a sealed sleeve through the wall, and a continuous vapor seal back to the wall vapor barrier. Sprinkler heads inside the cellar are corrosion-resistant rated because the cellar humidity is on the high side. Quick-response heads suited to high-value contents are normal practice, with the activation temperature appropriate to cellar ambient — a 68 degree quick-response head is standard, well above the 13 to 15 degree cellar setpoint with adequate margin.
For sprinkler runs that route inside HVAC supply duct envelopes — a configuration occasionally encountered in retrofit work — the sprinkler system is treated as part of the cellar volume and insulated externally with the duct. This is unusual and best avoided in new build because it complicates duct cleaning and sprinkler maintenance. New build should route sprinkler mains and HVAC duct independently, both on the cellar side of the vapor barrier, with separate maintenance access.
VESDA aspirating smoke detection — the cellar standard
Conventional point smoke detectors are slow to respond in a cellar or bonded warehouse for two reasons. The first is that the air at cellar temperature is dense and stratifies, so smoke from a low-level ignition event takes time to reach a ceiling-mounted point detector. The second is that the active mechanical ventilation in a bonded spirits warehouse drives smoke patterns away from natural ceiling stratification, so a point detector at the ceiling may not see the plume in time. The industry-standard answer is aspirating smoke detection — a system that continuously samples air through a network of capillary tubes and analyses it at high sensitivity for combustion particles.
The dominant aspirating system in this market segment is VESDA — Very Early Smoke Detection Apparatus — operating at sensitivities around 0.005 percent obscuration per metre, an order of magnitude or two more sensitive than point detectors. The sampling pipework is a network of small-bore plastic capillary tubes routed at high level through the cellar or warehouse, with sampling holes at engineered intervals. The aspirator unit pulls air through the network continuously and analyses it. A pre-alarm at low concentration triggers investigation, full alarm at higher concentration triggers suppression.
From an HVAC and duct perspective the VESDA installation has two design implications. First, the sampling tube routing must be independent of the supply duct. If the capillary network is routed inside HVAC supply duct it samples only the supply air, not the cellar atmosphere, defeating the purpose. The sampling network is mounted on the cellar ceiling under the supply duct, in the room volume. Second, the sampling pipework must be on the warm side of the vapor barrier where the network is at room temperature, and the aspirator unit must be located outside the cellar so its electrical equipment is in a controlled environment. Most practical installations route sampling pipework inside the cellar exposed at high level, with a single penetration through the wall to the aspirator unit on the warm side.
Why galvanised at 13 to 15 degrees, why coatings for premium
Galvanised steel duct is a standard specification for HVAC across virtually every Australian building type, and a wine cellar at 13 to 15 degrees with controlled 70 percent humidity is a benign environment for it. The hot-dipped galvanised coating to AS 1397 Z275 — meaning 275 grams per square metre minimum coating mass on each side, total — provides decades of corrosion protection at cellar conditions. Condensation does not collect on the duct surface because the duct is at cellar temperature, the cellar is enclosed, and the vapor barrier prevents moisture migration into seam areas. The galvanising chemistry is stable at cellar temperatures, with no aggressive vapor to attack the coating.
For premium private cellars and heritage display cellars a coated finish is sometimes preferred for visual reasons rather than performance reasons. The two practical options are factory pre-painted galvanised — with a polyester or PVDF topcoat applied to the coil before duct fabrication — and epoxy-coated galvanised, where the duct is fabricated and then powder-coated or wet-coated as a finished assembly. Both add cost and lead time over plain galvanised, and both require the SBKJ machine to be configured for the coil thickness on order. SBAL-V and SBAL-III lines run pre-painted coil without modification provided the coating is suited to the forming radii, which most modern polyester and PVDF coatings are.
The decision pivot is usually visual exposure. Cellar duct that is concealed above an architectural ceiling is plain galvanised. Duct that is exposed to view in a heritage cellar, tasting room or display area is coated, with the coating colour matched to the architectural palette. A typical project mixes both — the storage volume is plain galvanised, the public-facing tasting room is coated — and the SBKJ machine package produces both off the same tooling with a coil change.
304 stainless for spirit warehouse exhaust
For bonded spirits warehouses the exhaust runs are the corrosion-critical part of the duct system because they carry vapor-laden warehouse air. The recommended specification is 304 stainless steel for any duct that sees direct exposure to the warehouse atmosphere — exhaust grilles, riser ducts, exhaust mains and discharge stacks. 304 is preferred over 316 because the chloride exposure in a typical Australian inland or wine country location is low enough that 304 is adequate, and the cost differential to 316 is significant. 316 is justified only for coastal sites with significant salt aerosol exposure or for distilleries that include marine-influenced flavour compounds in their fermentation regime.
Stainless duct is more expensive than galvanised, fabricates slower because of the harder material, and welds rather than seam-locks at critical joints. Sealed-seam Class A construction is the appropriate standard for stainless exhaust to minimise leakage of vapor-laden air into ceiling cavities. SBKJ SBAL machines run 304 stainless coil with a tooling adjustment for the higher forming forces, and the machine line can be configured for stainless and galvanised in the same project with a coil change. For projects where the full exhaust train in stainless exceeds the budget, the practical compromise — already referenced earlier in the guide — is stainless on the high-vapor sections immediately downstream of grilles and on the discharge stack, with epoxy-coated galvanised on the intermediate runs.
Supply ductwork in a spirits warehouse can usually remain galvanised because the supply air is fresh atmosphere and is not vapor-laden. The supply diffusers and the first metre of supply duct downstream of any reheat coil are sometimes specified in coated or stainless construction as an extra margin against incidental vapor exposure during plant shutdown periods, but this is a refinement not a baseline.
Acoustic targets — NC-30 in tasting, NC-50 in storage
Acoustic targets in cellar and warehouse duct design follow the same NC noise criterion convention used across commercial HVAC. Storage halls are acoustically forgiving — operations occur infrequently, occupancy is low, and the brief tolerates supply duct noise at NC-50, which is a typical warehouse target. Diffusers are sized for face velocity below 4 metres per second to keep regenerated noise within target. Duct velocities in the main runs are held at 8 to 10 metres per second, which is normal for warehouse-class ducting.
Tasting rooms, public-facing cellar tour spaces and customer-facing retail boutiques inside the cellar envelope are acoustically tight by contrast. The target is NC-30 or quieter — equivalent to a quiet office — to allow conversation at normal volume without raising voice. Achieving NC-30 requires duct velocities held below 5 metres per second in the supply mains, diffusers sized for face velocity below 2.5 metres per second, attenuators in the supply path between plant and tasting room, and acoustic linings on duct walls in the last few metres before diffusers.
The catch with acoustic linings in cellar applications is humidity. Conventional fibreglass acoustic lining absorbs moisture, supports microbial growth, and in extreme cases sheds fibres into the cellar volume. The appropriate specification for cellar tasting rooms is closed-cell foam acoustic lining, faced and sealed against the cellar humidity, or external lagging on the duct outside with the duct internally smooth. External lagging is the cleaner specification because the duct interior remains stainless or galvanised metal that can be cleaned. Internal foam lining is acceptable when sealed properly but requires more disciplined commissioning to confirm the sealing.
Energy and NABERS Premises rating
The energy performance of cellar and warehouse HVAC is increasingly scrutinised under the NABERS rating framework. NABERS — the National Australian Built Environment Rating System — operates a Premises rating tool that assesses the energy and water performance of office and tenancy spaces, and a Whole Building rating that covers shopping centres, hotels and other building types. For wine and spirits storage facilities the relevant rating is the NABERS Energy for Premises framework where it applies, with continuing extension of the framework into specialist building types.
The HVAC design implication of NABERS is that energy consumption is metered and reported, so the cellar plant is sized and controlled to minimise consumption. The two highest-leverage design moves in a cellar context are oversized condensers — running at low approach temperature improves efficiency at the expense of footprint — and variable speed drive on the supply fan to match airflow to load. Cellar load profiles are extremely flat, so a fixed-speed fan running 24/7 at constant flow uses far more energy than a variable-speed fan modulating to the actual cooling demand.
For bonded spirits warehouses the ventilation rate is fixed by the dilution requirement, so there is less opportunity for variable-speed savings on exhaust fans without compromising the safety margin. The corresponding design move is heat recovery on the exhaust — a run-around coil or plate exchanger between exhaust and supply that recovers warmth in winter without compromising the dilution rate. Heat recovery on a four ACH ventilation system in a cool climate state recovers a meaningful fraction of the heating load and improves the NABERS profile materially.
SBKJ machine configuration — what produces this duct
The duct described in the preceding sections is produced on a small set of SBKJ machine configurations that are well matched to the wine and spirits storage segment. The standard recommendation for cellar and bonded warehouse work is an SBAL-V or SBAL-III auto duct production line for the rectangular galvanised work, configured for AS 1397 Z275 coil at 0.7 to 1.5 millimetre thickness. The line includes integrated TDF flange forming, sealed-seam Class A construction, and notch-and-cut for elbows and offsets. A typical line footprint is 30 to 45 metres of factory floor including coil decoiler, levelling, shearing, beading, seam closing, TDF flanging and stacking.
Where the project includes round duct for displacement supply or branch trunks — common in tasting rooms and cellar entries — the line pairs with an SBKJ spiral tubeformer running off the same coil store. The tubeformer produces lock-seam spiral pipe at any diameter from 100 to 1,500 millimetres at the rate the project requires, with the same Z275 galvanised coil specification. For premium archives where coated coil is specified the spiral tubeformer runs the coated stock with a tooling adjustment and reduced line speed to protect the coating.
For projects with stainless exhaust runs in spirits warehouses the SBAL-V or SBAL-III line runs 304 stainless coil with a tooling change. SBKJ engineers commission the line for the stainless campaign separately from the galvanised campaign, because the higher forming forces and harder material mean some tooling consumables need adjustment. The machine line itself does not need to be changed. A typical bonded spirits warehouse project will run two campaigns on the same SBAL line — galvanised for the bulk of the work, stainless for the exhaust.
The choice between SBAL-V and SBAL-III turns on volume and automation. For fabricators producing under 1,000 square metres of duct per month for cellar and bonded warehouse work, SBAL-III is the appropriate machine — manual coil load, semi-automated forming, manual offload. For fabricators producing over 1,000 square metres per month, SBAL-V with full automation, automatic coil change, automated stacker and integrated CAM software is the better fit because the labour saving justifies the capital differential. The detailed comparison sits in our companion guide on SBAL-V vs SBAL-III.
Integrating sprinklers, detection and HVAC at the cellar boundary
The most failure-prone area of cellar and warehouse construction is the boundary between cellar and surrounding warm building, where every service penetrates. HVAC supply and return duct, sprinkler mains and drops, electrical conduits, VESDA sampling pipework, refrigeration suction and liquid lines, control wiring and network cabling all cross the cellar vapor barrier. Every penetration is a potential vapor barrier failure and a potential thermal bridge.
The discipline that resolves this is service zoning. The cellar is served by a single mechanical service penetration block — typically a wall section dedicated to all the services entering from the warm-side plant room. Each service uses a sleeved penetration with a thermal break and a vapor seal. The sleeves are detailed at design stage and the penetration block is built first, with services routed to it in a coordinated fabrication sequence. Random penetrations as services come up during construction are the leading cause of failure — they are rarely sleeved properly and rarely sealed back to the vapor barrier.
For the HVAC duct specifically, the supply and return penetrations through the boundary are the largest single openings and require the most discipline. Each duct passes through a fabricated sleeve sized for the duct cross section plus the insulation thickness plus a 25 to 50 millimetre service gap for sealant. The duct is insulated externally on the warm side from the air handler all the way to the cellar wall, with the insulation continuous through the sleeve and sealed back to the cellar vapor barrier inside the cellar wall cavity. The sealant is closed-cell foam or rubberised mastic suited to the dew point at the seal.
Inside the cellar the duct sheds the external insulation because it is now at cellar temperature. The duct surface is metal, the cellar humidity is 70 percent, and condensation is not an issue because the duct is at room temperature. The same logic applies to return duct on the way back to the air handler — internally bare metal at cellar temperature inside the cellar, externally insulated and vapor-wrapped from the cellar wall back to the air handler. Sprinklers, electrical and refrigeration use the same penetration block with the same discipline.
Commissioning and acceptance — what 'good' looks like
Commissioning a cellar HVAC system is about confirming long-term stability rather than peak performance. Conventional commercial HVAC commissioning tests the plant at design day load and signs off if it meets setpoint. A cellar is the opposite — the brief is to confirm the cellar holds setpoint within a tight band over a sustained period, with the plant operating well below capacity most of the time.
The standard protocol runs as follows. After mechanical completion the cellar is sealed and stabilised for at least seven days with all permanent loads switched on. Temperature and humidity sensors at multiple points log at 5-minute intervals for the full week. The acceptance criterion is plus or minus one degree at all logged points and plus or minus five percent humidity. Any drift triggers investigation — usually a vapor barrier failure at a penetration or a stratification problem solved by supply diffuser repositioning.
For bonded spirits warehouses the protocol adds ventilation rate verification — exhaust measured at design flow against supply, with the resulting air change rate verified at or above 4 ACH including with one fan failed. Fire detection is exercised with a controlled smoke source at multiple points; the aspirating system is tested at all sample points by occluding individual capillaries. Acoustic testing in tasting rooms verifies NC-30 or quieter, and storage NC-50 or quieter, with attenuators or diffuser repositioning addressing any exceedance.
Long-term maintenance — keeping the cellar working for forty years
A cellar that commissions cleanly will run cleanly for a decade or more without intervention if the maintenance discipline is right. The high-leverage items are filter change frequency, vapor barrier integrity at penetrations, condensate drain clearance, refrigerant charge and condenser cleanliness, and sprinkler corrosion check. Each is straightforward when scheduled but expensive when neglected.
Filter changes in cellar supply ductwork are quarterly for private cellars and monthly for public-facing cellars with visitor traffic, using MERV-13 or HEPA on premium archives. Vapor barrier inspection is annual or biennial with thermal imaging during warmest ambient to find cold spots indicating a breach. Condensate drains are cleared annually — blocked drains are the single most common cause of cellar mould events. Refrigerant charge and condenser cleanliness are checked annually, with fouled condensers losing 10 to 20 percent capacity. Sprinkler corrosion checks follow AS 1851, with replacement at any sign of deterioration in the high-humidity environment.
Refurbishment, expansion and receiving airlocks
Cellars get expanded over time as stocks accumulate. The conventional approach is to phase works so the existing volume stays sealed and conditioned while the new volume is constructed up to lock-up, vapor barrier, insulation and HVAC plant. At join-up the new plant is fully commissioned and held at setpoint for at least 48 hours before the partition is removed. The partition removal happens at the coolest part of the day, with both plants running for the first 24 hours to cover the transient. Duct supply for the expansion uses the same SBAL-V or SBAL-III route at the same Z275 galvanised specification — consistency across phases is the master variable for long-term corrosion behaviour.
A specialised sub-case is the receiving dock in a bonded liquor warehouse. Premium wine arrives in temperature-controlled trucks at 13 to 15 degrees and the receiving operation must unload without exposing stock to ambient warehouse conditions. The conventional answer is a refrigerated airlock — a 3 by 3 metre vestibule held at cellar conditions with interlocked sliding doors, served by a 2 to 5 kW air handler with both supply and return inside the airlock volume. The vapor barrier wraps the airlock as a sub-cellar inside the warehouse. Duct is plain galvanised, fabrication is straightforward on an SBAL line.
Cross-references and companion guides
This guide focuses on the storage side of the wine and spirits supply chain. The three closest companion pieces in the SBKJ Insights library address adjacent territory and are worth reading together for anyone planning a comprehensive facility:
How SBKJ supports wine and spirits storage projects
SBKJ Group, headquartered in Box Hill North VIC, supports wine and spirits storage projects across two channels. For HVAC fabricators producing the duct, our SBAL-V and SBAL-III auto duct production lines are configured for the galvanised AS 1397 Z275 specification that dominates the segment, with the option of stainless and coated coil campaigns on the same machine line for premium and bonded projects. Lead time from order to commissioning is a planned 14 to 20 weeks, with installation supervision and operator training included in the standard contract. Our spiral tubeformer pairs with the SBAL line for round duct runs.
For end clients — wineries, distilleries, retail liquor groups, 3PL operators and bonded warehouse owners — SBKJ engineers provide design review of the proposed duct schedule against this guide before tender, and an itemised bill of duct on the SBKJ machine output basis. The review is independent of any specific fabricator selection and is offered as a value-added service to the design team. The output is a sanity-check document that the duct schedule is matched to the room briefs above, the materials are appropriate, and the bill-of-quantity is consistent with the machine production capability for the project schedule.
The Box Hill North VIC office covers the Australian and Pacific markets directly, with English-speaking after-sales engineers on Australian business hours. Our Insights library covers HVAC engineering for wine and spirits, brewing and distilling production, cold chain and frozen storage, distribution warehousing, food and beverage processing, pharmaceutical cleanrooms, and other specialised duct applications. For a quotation against this guide, or for engineering review of a design in progress, contact the SBKJ engineering team through the contact link below.
Get an SBKJ engineering review of your cellar or bonded warehouse duct schedule →
FAQ
What temperature and humidity should a long-term wine cellar hold?
For long-term cellaring the consensus window is 13 to 15 degrees Celsius held within plus or minus 1 degree, and 70 percent RH held within plus or minus 5 percent. Stability matters more than the absolute number — a cellar held steady at 14 degrees ages better than one swinging from 12 to 16. Light is held to near zero with no UV in the lamp spectrum, and vibration is held below 0.1 g.
How is a bonded spirits warehouse different from a wine cellar in HVAC terms?
A bonded spirits warehouse holds product releasing alcohol vapor, so the priority shifts from absolute temperature stability to ventilation rate, vapor dilution and ignition source control. Minimum ventilation in a maturation hall is 4 ACH, with 304 stainless steel for exhaust runs to resist alcohol vapor corrosion. Wine cellars by contrast prioritise minimum air movement and tight humidity rather than dilution.
Why galvanised duct in a wine cellar but stainless in a spirits warehouse?
At 13 to 15 degrees and 70 percent RH a wine cellar is benign for hot-dipped galvanised AS 1397 Z275 duct — condensation is controlled, there is no aggressive vapor, galvanising lasts the building life. A bonded spirits warehouse is different because ethanol vapor at storage concentrations attacks zinc coatings over time, so 304 stainless or epoxy-coated galvanised is preferred for exhaust runs that see direct vapor exposure.
What does Australian excise law require of a bonded liquor warehouse?
A bonded warehouse holding excisable wine and spirits in Australia operates under the Excise Act 1901 and Customs Act 1901, with ATO licensing of the premises. Duty is deferred until the goods are released for home consumption. The site must be physically secure, accurately inventoried, and built so HVAC ductwork does not provide unmonitored paths between bonded and unbonded zones. State liquor licensing applies on top of the federal excise framework.
What SBKJ machine configuration is standard for cellar and bonded warehouse projects?
For Australian wine cellar and bonded spirits warehouse projects the standard package is an SBAL-V or SBAL-III auto duct production line configured for hot-dipped galvanised AS 1397 Z275 coil at 0.7 to 1.5 mm thickness, with sealed-seam Class A construction and TDF flange forming. A spiral tubeformer pairs with the line for round displacement supply runs. Premium archives and bonded spirits exhaust runs add stainless or coated coil campaigns on the same line.
