What is the Bizot Group climate envelope and why has it replaced the older ASHRAE Class A 21 degrees Celsius plus or minus 1 specification for Australian museum loan agreements?

The Bizot Group — formally the International Group of Organizers of Large-scale Exhibitions, which is the standing group of directors of the major collecting institutions worldwide — published a reframed museum and gallery climate specification in 2014 that has since become the most widely accepted international loan-agreement standard. The Bizot envelope is 16 to 25 degrees Celsius and 40 to 60% relative humidity, with permitted excursions plus or minus 5% RH over any 24-hour period and plus or minus 10% RH over a 12-month period. It is a substantially broader envelope than the older ASHRAE Chapter 21 Class AA 21 plus or minus 1 degree Celsius and 50 plus or minus 5% RH specification that dominated museum loan practice from the 1970s to the early 2010s, and it deliberately accommodates the energy-efficiency and carbon-reduction pressure that every major institution now faces. In Australian practice the National Gallery of Australia, the National Library, the National Museum and the major state galleries have all adopted Bizot as the default loan envelope, with the older tighter envelope reserved for the rare exceptional loan from an institution that has not yet moved to Bizot or for the very small subset of materials — some hygroscopic ivory, some lacquerware, some panel paintings — that still need the tighter envelope on conservation grounds. The HVAC design consequence is that the air-handling plant has a wider permissible humidity range, but the rate-of-change limit (plus or minus 5% over 24 hours) is the binding constraint, and the duct distribution still has to deliver SMACNA Class A leakage and stable supply temperature across the full gallery footprint.

Why is Novec 1230 or INERGEN clean-agent suppression specified instead of AS 2118 wet sprinkler for a national library, archive or gallery storage zone?

A wet sprinkler discharge over irreplaceable cultural material — a 19th-century manuscript, an oil-on-canvas panel painting, an Aboriginal bark painting, a colonial photographic print, an early Federation-era nitrate film reel, a hand-coloured atlas plate, a leather-bound first-edition manuscript — produces water damage that is in many cases irreversible. The international consensus across ICOM, IIC, AICCM, the AIC and every major national collecting institution is that water-based suppression is unsuitable as the primary suppression system for the storage of irreplaceable collection material. The Australian Standard AS 4214 Gaseous Fire Extinguishing Systems sets out the engineering requirements for the alternative — clean-agent suppression that extinguishes by displacing oxygen or by absorbing heat rather than by wetting the protected fabric. Four agents dominate the heritage and collection space: FM-200 (HFC-227ea) for the legacy installation stock; Novec 1230 (FK-5-1-12 fluoroketone) as the preferred new-build choice on environmental and atmospheric-lifetime grounds; INERGEN (IG-541, a blend of nitrogen, argon and carbon dioxide); and pure-nitrogen IG-100 in some recent retrofits. The duct designer's responsibility is the agent hold-time engineering — the protected enclosure has to maintain design agent concentration for the AS 4214 hold time (typically 10 minutes) after discharge, which means the supply and return duct dampers have to close to the protected zone on the same fire-detection signal that triggers agent release, and the enclosure integrity is verified by a fan-pressurisation door-fan test on commissioning. Where the heritage agency requires a secondary water-based system for the very small fire that does not reach detection threshold, an AS 2118 pre-action sprinkler is specified to charge only on a second-stage detection signal so the protected zone never carries water in the sprinkler pipework under normal conditions.

How small can concealed ductwork be inside a heritage library reading room such as the State Library of Victoria La Trobe Reading Room or the Mitchell Library reading room at the State Library of NSW?

The La Trobe Reading Room dome at the State Library of Victoria (the 1856 octagonal dome above the reading room floor, completed in its current form in 1913), the Mitchell Library reading room at the State Library of NSW (1910), and the National Library of Australia main reading room in the 1968 Bunning and Madden building all share a common HVAC routing challenge — the architectural significance of the reading room interior precludes any new visible duct or diffuser penetration through the dome glazing, the heritage plaster, the timber wainscot or the decorative bronzework. The concealment envelope is 80 to 200 mm diameter spiral round duct produced on the SBFB-1500 spiral tubeformer for the supply branch distribution that threads through the original ventilation lay-light slots in the dome glazing and the cavity above the heritage plaster ceiling, and 150 to 250 mm rectangular duct for the secondary distribution at the perimeter behind decorative cornice. The original Victorian-era reading room buildings had a substantial passive ventilation system based on lay-light slots and stack-effect risers, and the most defensible modern HVAC strategy uses those original ventilation paths as the concealed routes for the new ductwork rather than cutting new penetrations. The SBSF-1525 stitchwelder produces the rectangular duct in the 100 to 300 mm band that fits into the cornice cavity, the SBFB-1500 spiral produces the small-diameter round, and the SB-ZF1500 stitchwelder produces the 304 stainless plenum casing around silencer assemblies that sit out of view above the false ceiling.

What ventilation rate and exhaust strategy applies to a conservation laboratory fume cupboard inside a national or state museum, gallery or library conservation department?

A conservation laboratory inside a major collecting institution operates as a NCC Class 9a healthcare-equivalent or Class 8 laboratory occupancy, and the fume cupboard ventilation is the dominant design constraint. AS 2243.8 Safety in Laboratories sets the face-velocity requirement (typically 0.5 metres per second for general conservation chemistry, higher for specialised activities) and the exhaust ducting requirement (dedicated exhaust, no shared duct with general ventilation, discharge to roof above any building air intake by a minimum vertical separation set by the AS 1668.2 dispersion calculation). The exhausted compounds include the full conservator solvent palette — acetone, methyl ethyl ketone (MEK), isopropanol, ethyl acetate, ethanol, white spirit and the legacy toluene that is being phased out — plus the alkyd resin, varnish remover, paint stripper, ammonia-based cleaning solution, oxalic acid for paper conservation, peracetic acid for textile sanitation, and the occasional hydrochloric acid for legacy print-etching and manuscript stabilisation work. The duct material at the fume cupboard exhaust is 316L stainless on the SBAL-V auto duct line, sized for the velocity requirement, with a corrosion-resistant Type 316L stainless centrifugal exhaust fan in spark-resistant configuration, no recirculation, and a continuous monitor on the face velocity that alarms if the velocity drops below the AS 2243.8 minimum. A separate local exhaust ventilation (LEV) hood serves the conservation bench for solvent decanting and small-batch work.

How is the National Film and Sound Archive nitrate film cold storage HVAC-conditioned for the 35mm nitrate cellulose stock under federal regulation?

Cellulose nitrate film stock — the dominant motion-picture film stock from 1895 to about 1951, when it was progressively replaced by safety acetate — is a Class 4.1 flammable solid under the dangerous goods classification and a self-oxidising material that does not require an external oxygen supply for combustion. The National Film and Sound Archive Acton in the Australian Capital Territory holds the country's most significant collection of nitrate stock and operates a dedicated cold-storage vault for it. The vault HVAC envelope is 4 to 10 degrees Celsius and 30 to 35% relative humidity, with a vault construction rated to AS 1530.4 for fire resistance and a fire suppression system that historically used carbon dioxide or halon and has migrated under current AS 4214 to INERGEN or IG-541 inert gas. The ventilation is dedicated to the nitrate vault, no recirculation, and the exhaust discharges through a flame-arrestor stack to the roof. The supply and exhaust ductwork is welded 316L stainless on the SBAL-V line, the dampers are fail-closed on agent release, and the access protocol requires a permit-to-work signed by the Archive's fire safety officer before any person enters the vault. The Spielberg and Walsh holds at NFSA are nitrate-vault grade. The general film and sound archive collection sits in a lower-risk acetate and polyester-base vault at 2 to 8 degrees Celsius and 25 to 30% RH, with conventional clean-agent suppression.

What environmental class and visible-light limit applies to a paper, textile or watercolour gallery display under the international consensus museum lighting standard?

The international consensus across ICOM, IIC, AIC, AICCM and the IPI Image Permanence Institute sets visible light limits by material sensitivity. The most light-sensitive category — works on paper, watercolours, textiles, dyed leather, photographic prints, manuscripts and natural-dye Aboriginal bark paintings — is held at 50 lux maximum visible illumination and ultraviolet content less than 75 microwatts per lumen. The medium-sensitive category — oil paintings, acrylic paintings, undyed leather, lacquer, bone and ivory — is held at 200 lux maximum. The low-sensitive category — stone, ceramic, metal, glass and unpainted wood — is held at 300 lux maximum, with no UV restriction in practice. The Bizot Group climate envelope (16 to 25 degrees Celsius, 40 to 60% RH) applies across all three categories. The HVAC design implication is that the supply diffuser and the lighting fixture coexist in the gallery ceiling, the duct routing avoids conflict with the lighting track, and the gentle laminar supply across the gallery is in the range 0.1 to 0.15 m/s face velocity at the diffuser exit, well below the draught threshold and the conservator's noticeable-air-movement threshold. The lighting fixtures are LED at 2700 to 3500 Kelvin warm white with UV-filtered diffuser caps, and the supply temperature is controlled to prevent any thermal stratification that would draw warm air across the canvas surface.

How is the high-density mobile shelving (Compactus, Bruyne, Spacesaver) inside a national archive or library reserve stack ventilated to meet ISO 11799 and the BS 5454 archive storage standard?

Mobile compact shelving — Compactus, Bruyne and Spacesaver Bracha are the three Australian-market brands — collapses 4 to 6 traditional fixed-shelf bays into a single mobile aisle bay, with the working aisle opening on demand. The HVAC challenge is that the air movement around the closed bays is by definition near-zero, and the ISO 11799 archive storage standard sets the requirement for a uniform climate envelope across the closed bay interior. The Australian and international design response is to provide a low-velocity supply at the room periphery (typically a long-throw slot diffuser at the upper wall) and a low-level return at the floor that draws conditioned air through the bay structure by induced flow when the aisle opens, and by gentle convective recirculation when the aisle is closed. The room itself is held at 16 to 18 degrees Celsius and 40 to 50% RH (a tighter envelope than the gallery Bizot envelope because the archive material is paper-dominant and the institution is the long-term custodian), and the duct construction is SMACNA Class A on the SBAL-V auto duct line in galvanised steel for the general air, with 304 stainless on selected branches that pass through the fire-suppression-protected envelope where chloride exposure from the gaseous agent could attack galvanised material. Gas suppression is INERGEN or Novec 1230 per AS 4214.

How is a heritage museum interior such as the State Library of Victoria, the Mitchell Library, the Australian Museum 1827 building or the Australian War Memorial Hall of Memory HVAC-routed without damaging significant heritage fabric?

The dominant Australian heritage museum and library stock predates modern HVAC by 50 to 150 years, and the architectural significance of the interior precludes new visible duct penetrations, new diffuser cuts through dressed sandstone or original plaster, and any fixings that damage significant fabric. The Burra Charter 2013 sets the operative principles — do as much as necessary and as little as possible, retain significance, prefer reversible interventions, document everything. The concealment strategy uses the existing voids that the original architecture provided — the disused chimney flues from the original coal and gas heating systems, the cavity above the lath-and-plaster ceiling, the under-floor void above the basement, the original organ-loft riser space, the lay-light cavity above the dome glazing, the cavity behind heritage timber wainscot and decorative cornice mouldings. The duct routing through these voids uses small-diameter spiral on the SBFB-1500 (80 to 200 mm) for the branch supply and the SBSF-1525 stitchwelder for rectangular duct in the 150 to 300 mm depth band. The diffusers are heritage-compatible reproductions in cast iron, brass or bronze that match the original room's decorative scheme rather than modern slot or linear diffusers, and the plant compound sits outside the heritage curtilage in a non-significant addition. The Statement of Heritage Impact documents every metre of duct retained, removed, replaced or newly installed under the relevant state heritage act.

What SBKJ duct production machinery is recommended for a national or state library, museum, archive, gallery or conservation laboratory project?

For the typical Australian collecting institution project combining a public gallery zone, an archive reserve stack, a conservation laboratory, a back-of-house plant compound and a heritage-interior reading room, SBKJ recommends the SBAL-V auto duct line on galvanised steel coil to AS 1397 Z275 (0.8 to 1.2 mm) for general trunk distribution and the gallery supply, with the same line tooled for 304 stainless coil (1.2 to 1.5 mm) for the conservation laboratory exhaust trunk and the heritage cellar storage. The SBAL-V is reconfigured for 316L stainless 1.5 mm for fume cupboard exhaust and the chloride-exposed paths around clean-agent suppression. The SBFB-1500 spiral tubeformer produces 80 to 250 mm small-diameter concealed spiral for heritage reading-room routing and the small-bore branch supply to gallery diffusers concealed in cornice cavities. The SBSF-1525 stitchwelder produces the 100 to 300 mm rectangular duct in the concealed routing band and the 150 to 600 mm general distribution. The SB-ZF1500 stitchwelder produces 304 and 316L stainless plenum casings and silencer assemblies for the NC-25 reading room and the NC-25 conservation lab. The SBPC1500 plasma profiler cuts custom stainless plate fittings for the fume cupboard transitions, the nitrate-vault flame-arrestor stack and the heritage diffuser bird-mouth profiles. The SBLR-600 longitudinal welder produces NFPA 96 black-steel exhaust for the museum cafe and gift-shop commercial kitchen, and the same welder is used for the high-temperature exhaust on the thermal pest-treatment chamber at 50 degrees Celsius. The SBTF-1500, SBTF-1602 and SBTF-2020 close-coupled tubeformer handles wider-band spiral up to 2,000 mm for the main supply trunks in the larger institutional projects such as the National Library and the National Gallery.

Insights · Library, Museum, Archives, Gallery, Conservation & Cultural Heritage

National Library, Museum, Archives, Heritage Collection, Gallery, Art Conservation Lab & Cultural Heritage HVAC Ductwork Guide

A senior-engineer reference for HVAC ductwork design across Australian national libraries, state libraries, national archives, national and state museums, national and state galleries, conservation laboratories and cultural-heritage collections — National Library of Australia Canberra, National Archives, National Museum, National Gallery, Australian War Memorial, National Film and Sound Archive, the State Libraries and State Museums of every jurisdiction, MONA Hobart and MAGNT Darwin. Written from Box Hill North, Victoria by the SBKJ engineering team and grounded in the ASHRAE Applications Handbook Chapter 21, the Bizot Group climate envelope, ISO 11799, BS 5454, the AICCM Australian Institute for the Conservation of Cultural Material guidance, the Burra Charter 2013, AS 1668.2, AS 4254 and AS 4214 clean-agent suppression.

By SBKJ Engineering Team · Published May 21, 2026 · 44 min read · Reviewed by SBKJ QA & Engineering

SBKJ Group acknowledges the Traditional Custodians of Country across the Australian continent and pays respect to Elders past, present and emerging. We acknowledge that the national, state and regional collecting institutions described in this guide are custodians of cultural material that includes Aboriginal and Torres Strait Islander objects, manuscripts, sound recordings, photographs and ceremonial items, and that the proper care of those collections sits inside a wider cultural-heritage conversation in which Traditional Owners and communities are the appropriate authority. Heritage HVAC engineering, done well, supports the institution's broader obligations to community, Country and culture rather than substituting for them.

1. Why national library, museum, archives, gallery and conservation engineering is a separate category

The Australian collecting-institution typology — the national libraries, the national archives, the national museums, the national and state galleries, the national and state-level art and cultural-heritage repositories, the conservation laboratories and the cultural-heritage centres — sits in its own engineering category for one reason. The HVAC system here is not a comfort system. It is a preservation system. The temperature, the humidity, the rate of change, the particulate load, the gaseous pollutant load and the visible-light spectrum reaching the protected fabric all directly determine whether the irreplaceable manuscript, the panel painting, the bark painting, the convict-era ration book, the World War One diary, the 1908 nitrate newsreel, the Aboriginal ceremonial object or the colonial daguerreotype survives the next 100 years or degrades to unreadable in 20. Get the HVAC envelope wrong and the institution loses fabric that the country cannot replace.

The HVAC engineering consequence of that brief is concrete, and it is unusual relative to the rest of the building services portfolio. The temperature setpoint band is narrower than office (20 to 22 versus 22 to 26 degrees Celsius), the humidity tolerance is tighter (40 to 60% RH plus or minus 5% over 24 hours rather than uncontrolled), the rate-of-change limit is the binding design constraint rather than the absolute setpoint, the duct construction is SMACNA Class A leakage rather than the Class B that an office building tolerates, the filter rating is MERV 13 to MERV 15 rather than the MERV 8 that an office takes, the fire suppression is gaseous clean-agent rather than wet sprinkler, the lighting is colour-temperature-controlled and visible-light-limited rather than uniform-lumen task lighting, and the duct routing has to thread through a heritage interior that the architectural profession will not permit the engineer to damage. The conservator and the registrar sit at the design-team table alongside the architect and the mechanical engineer, and the conservator's view on humidity rate-of-change carries more weight than the energy-efficiency consultant's view on outdoor-air reset strategy.

This is the SBKJ engineering team's working reference for that brief. We have written it from our Box Hill North office in Victoria, drawing on three decades of designing the duct production machinery that fabricates ducted HVAC for the collecting institutions of this country — from the National Library of Australia and the National Gallery in Parkes through the National Archives reading rooms in every state capital, the Australian War Memorial in Campbell, the State Library and State Museum of every jurisdiction, the major regional galleries, MONA in Hobart, and the conservation laboratories at AICCM-accredited treatment centres across the country. The article is structured so the international and national frameworks come first, then the per-zone environmental class and per-material conservation parameters, then heritage-interior concealment strategy, then the major institutional building types and their per-zone HVAC architecture, then the building services details that recur across them all, and finally the duct manufacturing implications and the SBKJ machinery configurations that fabricate the resulting duct economically.

2. The international and national conservation framework — ICOM, IIC, AICCM, the Bizot Group and ASHRAE Chapter 21

Six standing bodies dominate the global museum and conservation engineering conversation, and the Australian practice operates inside their consensus. They are: the International Council of Museums (ICOM), founded 1946 and based in Paris, with Australian chapter ICOM Australia operating as Museums Australia ICOM Australia; the International Institute for Conservation of Historic and Artistic Works (IIC), founded 1950 and based in London; the American Institute for Conservation (AIC); the Australian Institute for the Conservation of Cultural Material (AICCM), the peak Australian conservation professional body, which administers the AICCM Code of Ethics and the AICCM Accreditation scheme that certifies practising conservators in this country; the Image Permanence Institute (IPI) at the Rochester Institute of Technology, which sets the standards for photographic, film and electronic-media preservation that the National Film and Sound Archive applies in Australia; and the Bizot Group, formally the International Group of Organizers of Large-scale Exhibitions, which is the standing director-level forum that sets the loan-agreement climate-envelope standard for international exhibition exchange.

The Australian engineering practice applies the framework as follows. ASHRAE Applications Handbook Chapter 21 (Museums, Galleries, Archives and Libraries) is the technical reference. It is THE standard the senior consulting engineers and the institutional facilities engineers use as the working textbook, and it has been the dominant reference in Australian practice since the early 1990s. The chapter sets out five environmental classes (AA, A, B, C, D) by tightness of control, with AA the tightest (21 plus or minus 1 degree Celsius and 50 plus or minus 5% RH year-round) and D the loosest (no control of either). The Bizot Group 2014 reframe broadened the institutional consensus to 16 to 25 degrees Celsius and 40 to 60% RH, with plus or minus 5% over 24 hours and plus or minus 10% over 12 months. Most Australian collecting institutions have adopted Bizot for general gallery and exhibition use, retaining the tighter ASHRAE Class AA only for the small subset of high-sensitivity material and for incoming loans from institutions that have not yet moved to Bizot. The archive reserve stack, by contrast, sits on a tighter envelope — 16 to 18 degrees Celsius, 40 to 50% RH plus or minus 5% over 24 hours — because the archive material is paper-dominant and the institution is the long-term custodian rather than a temporary host.

The supporting standards that the engineer applies alongside Chapter 21 are: ISO 11799 Information and documentation — Document storage requirements for archive and library materials; BS 5454 Recommendations for the Storage and Exhibition of Archival Documents (the British Library standard, retained in Australian institutional practice for the long-form storage detail); ISO 18934 Imaging materials — Multiple media archives — Storage environment (the IPI standard for mixed-media archives); the AICCM Australian guidance, including the AICCM Bulletin and the AICCM Code of Ethics; and the ICOM Code of Ethics for Museums (in particular Section 2 on collections). For Aboriginal and Torres Strait Islander material the federal Aboriginal and Torres Strait Islander Heritage Protection Act 1984 sits above the institutional framework, and the institution's protocols with the relevant Traditional Owner communities determine whether and how the material is displayed, stored and accessed.

3. The Australian operator landscape — national, state and major regional institutions

The Australian collecting-institution sector divides into three tiers. Understanding the tier matters to the HVAC engineer because the procurement framework, the project budget, the conservation expectations and the heritage-fabric constraints differ substantially across the tiers.

The national institutions. The major federal cultural institutions cluster in the Australian Capital Territory, with reading rooms and outposts in every state capital. The National Library of Australia (NLA) in Parkes ACT is the country's largest research library, holding more than 10 million volumes plus the Trove digital archive that aggregates the digitised collections of the federation; the main building is the 1968 Bunning and Madden brutalist envelope on Parkes Place. The National Archives of Australia (NAA) holds the federal government records from 1901 onward, with reading rooms in Canberra, Sydney, Melbourne, Brisbane, Perth, Adelaide, Hobart and Darwin. The National Museum of Australia (NMA) on the Acton Peninsula covers Aboriginal and Torres Strait Islander, convict, colonial and contemporary Australian material. The National Gallery of Australia (NGA) in Parkes is the country's largest art museum with Aboriginal, Asian, European and contemporary collections and the outdoor Sculpture Garden. The National Portrait Gallery sits adjacent to the NGA in Parkes. The National Film and Sound Archive (NFSA) in Acton holds the country's film, sound, video and digital recording archive, including the nitrate-film cold-storage vaults. The Australian War Memorial (AWM) in Campbell ACT combines the Anzac and conflict memorial function with the Roll of Honour and Bean's Hall of Memory in the heritage 1941 building.

The state libraries and state museums. Each state and territory maintains a state library and a state museum, with the major capital-city institutions operating at federal-equivalent scale and the regional branches operating at substantial scale. The State Library of New South Wales (SLNSW) on Macquarie Street Sydney dates from 1826 and is the country's oldest library, incorporating the heritage Mitchell Library (1910). The State Library of Victoria (SLV) on Swanston Street Melbourne contains the La Trobe Reading Room dome (1856, current form 1913). The State Library of Queensland (SLQ) sits in the Brisbane Cultural Centre at South Bank. The State Library of Western Australia is in the Perth Cultural Centre. The State Library of South Australia is on North Terrace Adelaide. The State Library of Tasmania is in Hobart and the Northern Territory Library is in Darwin. The state museums include the Australian Museum (Sydney, 1827, the country's oldest natural-history museum, with Aboriginal and Pacific collections), the Powerhouse Museum of Applied Arts and Sciences (MAAS, Ultimo Sydney with the proposed new Parramatta facility), the Art Gallery of NSW (AGNSW, Domain Sydney, plus the 2022 Naala Badu Sydney Modern wing), Sydney Living Museums (12 historic Sydney houses including the Museum of Sydney, Hyde Park Barracks, Vaucluse House, Elizabeth Bay House, Susannah Place, The Mint, the Justice and Police Museum, and the Caroline Simpson Library), the Anzac Memorial Sydney in Hyde Park, the Australian National Maritime Museum (ANMM) at Darling Harbour, the Sydney Observatory, Melbourne Museum (Carlton Gardens, adjacent to the UNESCO Royal Exhibition Building), NGV National Gallery of Victoria (the St Kilda Road International, the Federation Square NGV Australia, and the broader NGV portfolio), the Immigration Museum (Old Customs House on Flinders Street Melbourne), the Old Treasury Building, the Old Melbourne Gaol, ACMI Australian Centre for the Moving Image at Federation Square (reopened 2021 after the redevelopment), Heide Museum of Modern Art (Bulleen VIC), Tarrawarra Museum of Art (Yarra Valley), Geelong Gallery, Bendigo Art Gallery, Ballarat Fine Art Gallery, Castlemaine Art Museum, QAGOMA Queensland Art Gallery and Gallery of Modern Art (South Bank Cultural Precinct), Queensland Museum (South Bank), Museum of Brisbane (City Hall), Cobb and Co Museum Toowoomba, WA Museum Boola Bardip (Perth Cultural Centre, reopened 2020), the Art Gallery of Western Australia (AGWA) in the Perth Cultural Centre, the Perth Mint Heritage, the South Australian Museum (North Terrace Adelaide, with world-class Indigenous Australia collections), the Art Gallery of South Australia (AGSA), the Adelaide Botanic Garden, the SA Maritime Museum at Port Adelaide, the Tasmanian Museum and Art Gallery (TMAG) on Davey Street Hobart in the heritage 1830s building with convict collections, MONA Museum of Old and New Art in Berriedale Hobart (David Walsh's privately-funded museum, opened 2011, the country's largest privately-funded museum), the Royal Tasmanian Botanical Gardens, and the Museum and Art Gallery of the Northern Territory (MAGNT) at Bullocky Point Darwin.

Specialist conservation centres and art-handling logistics. The conservation laboratories include the NLA Conservation Lab, the NAA Preservation Centre, the NGA Conservation Department, the NMA Conservation Department, the AWM Conservation Department, the conservation laboratories embedded in each State Library, the University of Melbourne Grimwade Conservation Services, and Materials Conservation Services in Sydney. The Aboriginal cultural centres and Indigenous art centres operate across the country with the Kluge-Ruhe collection link maintained between the University of Virginia and Sydney institutions. The specialist art-handling and packing operators — International Art Services (IAS), Schneider, Crozier Fine Arts, Pickfords Fine Arts, Yelland Art and Allied Pinnacle Fine Art Logistics — provide the loan-eligible transit envelope that supports the institutional loan programme, with Museum Insurance Brokers covering the loan-risk position. The peak professional body is AICCM Australian Institute for the Conservation of Cultural Material, and the institutional director's forum is the Council of Australasian Museum Directors (CAMD) for museums, the Council of Australian Art Museum Directors (CAAMD) for galleries, and National and State Libraries Australia (NSLA) for libraries. The Australian Library and Information Association (ALIA) is the librarian-side peak body, including the ALIA Special Libraries Australasia stream that includes the institutional conservation librarians.

4. The environmental class per zone — the Bizot envelope and the conservation-specific bands

The dominant per-zone HVAC envelope inside an Australian collecting institution is structured by material sensitivity rather than by space function alone. The conservator and the registrar set the envelope on the room data sheet, and the engineer sizes the plant and the duct distribution to deliver it.

The general gallery and exhibition zone. Bizot Group envelope: 16 to 25 degrees Celsius and 40 to 60% relative humidity, plus or minus 5% RH over any 24-hour period and plus or minus 10% RH over any 12-month period. NCC Class 9b assembly occupancy at 200 to 2,000 visitors. The rate-of-change limit is the binding design constraint, not the absolute setpoint, and the duct sizing has to deliver gentle laminar supply across the gallery footprint at 0.1 to 0.15 metres per second face velocity at the diffuser exit. The supply temperature is controlled to avoid any thermal stratification that would draw warm air across a canvas surface, and the supply diffusers coexist in the ceiling with the lighting track in a heritage-compatible geometry. The CO2 setpoint reset target is below 1,000 ppm with a design tolerance to 1,500 ppm during the weekend and school-holiday peak visitor density. Acoustic criterion NC-30 to NC-35. Visible light limit 50 lux for paper, textile, watercolour and dyed leather; 200 lux for oil paint and acrylic; 300 lux for stone, metal and ceramic. UV less than 75 microwatts per lumen across all material classes, with UV-filtered ScotchLite or equivalent UV-visible-IR blocking film on every glazed envelope and LED lighting at 2700 to 3500 Kelvin warm white.

The archive reserve stack and repository. ISO 11799 compliant: 16 to 18 degrees Celsius, 40 to 50% RH, plus or minus 5% RH over 24 hours. The space typically contains high-density mobile shelving on a Compactus, Bruyne or Spacesaver Bracha track system, with 4 to 6 traditional fixed-shelf bays collapsed into a single mobile aisle bay. The HVAC strategy is low-velocity perimeter supply (long-throw slot diffuser at the upper wall) with low-level return at the floor, no recirculation back into other zones, MERV 13 to MERV 15 filtration, and a separate climate zone per material class (paper-dominant in one zone, photographic in a second, magnetic and optical media in a third, textile in a fourth). Gas suppression Novec 1230, FM-200, INERGEN or IG-541 under AS 4214; no sprinkler water as primary suppression; AS 2118 pre-action sprinkler only released after gas, on a second-stage detection signal. No anti-pest fumigation in the live storage zone — pest management happens at the receiving room before the material enters reserve.

The conservation laboratory. NCC Class 9a healthcare-equivalent or Class 8 laboratory occupancy. Climate 18 to 22 degrees Celsius and 45 to 55% RH. Fume cupboard exhaust per AS 2243.8, with face velocity 0.5 metres per second minimum for general chemistry and higher for specialised activities. Local exhaust ventilation (LEV) at the conservation bench for solvent decanting and small-batch work. HEPA H13 or H14 filtration on the supply where the work involves sensitive cleaning. Chemical-resistant epoxy floor. The lab is AICCM-certified and the conservator may also hold Royal Society Conservation accreditation or RAAF Conservation Centre certification (the AWM and NFSA paths). The treatment scope spans paint, textile, paper, book, manuscript, leather, wood, plastic, metal, ceramic, stone, photographic, film and digital-media restoration.

The rare books, manuscripts, cards, maps and atlas room. 16 to 18 degrees Celsius, 40 to 45% RH, plus or minus 3% RH over 24 hours. This is a tighter envelope than the general reserve stack because the material is uniquely vulnerable. The State Library of NSW Mitchell Library, the State Library of Victoria La Trobe Reading Room, the National Library of Australia Manuscripts Room and the rare-books rooms at the major state libraries operate at this envelope. The room is pollution-controlled (gaseous-pollutant scrubbing on the outdoor-air intake), UV less than 10 microwatts per lumen, visible light less than 50 lux during reader-access periods and switched off when no reader is present.

The audio-visual and film archive. The NFSA holds the country's most significant collection. The general acetate and polyester film vault operates at 2 to 8 degrees Celsius and 25 to 30% RH. The nitrate-film vault operates at 4 to 10 degrees Celsius and 30 to 35% RH with a flame-arrestor exhaust stack and INERGEN or IG-541 inert-gas suppression (replacing the legacy CO2 and halon configurations). The Spielberg and Walsh holds at NFSA carry the nitrate-vault grade engineering. The digital-media and magnetic-tape archive operates at 15 to 18 degrees Celsius and 30 to 40% RH.

The museum registration and acquisition receiving room. This is the quarantine point for new acquisitions before they enter the collection. Integrated pest management (IPM) protocols apply: anoxic CO2 or nitrogen fumigation chamber for 14 to 21 days at less than 0.1% residual oxygen, thermal pest treatment at 50 degrees Celsius for 72 hours, freezer treatment at minus 25 degrees Celsius for 7 to 14 days. The room is a separate zone from the collection storage with independent supply and exhaust, no recirculation, and the capability to exhaust nitrogen or CO2 overflow to outdoors. Cryotech and equivalent specialist suppliers provide the chamber equipment.

The conservation darkroom. Rare in modern practice but retained at some institutions for silver gelatin, albumen, collodion and platinum-print conservation. Fixed-wash and silver-recovery (Ag recovery) infrastructure with pH-controlled drainage. Climate 18 to 22 degrees Celsius and 50 to 60% RH. The exhaust is dedicated, the duct is 316L stainless to resist silver-fixer corrosion, and the room is light-controlled with the safelight at the appropriate wavelength.

Taxidermy, sculpture and moulage conservation. Organic specimens conditioned at 16 to 18 degrees Celsius and 40 to 50% RH, with the additional exhaust requirement for the ethanol and formalin preservatives used on the wet-specimen collections. The exhaust is dedicated and the duct is 316L stainless.

Reading room and reading carrel. 20 to 24 degrees Celsius and 40 to 55% RH. Outdoor-air rate 10 L/s per person plus the area-based component. CO2 reset to maintain less than 1,000 ppm in the breathing zone. Acoustic criterion NC-25 to NC-30 for quiet study. The heritage reading rooms (the SLV La Trobe Reading Room dome, the SLNSW Mitchell Library reading room, the NLA main reading room) carry additional concealed-routing constraints described in section 5.

Children and education room. Higher outdoor-air rate (12 L/s per person) and tighter CO2 control because the occupant population is more vulnerable. Interactive use produces higher metabolic loads. Acoustic criterion NC-35.

Digitisation laboratory. Scanning, OCR and digital migration suite. Climate-controlled to 20 to 22 degrees Celsius and 40 to 50% RH, electrostatic-discharge-safe floor, lighting-controlled to avoid photometric artefacts during high-resolution scanning of paper and photographic material.

Atrium and foyer. NCC Class 9b assembly. Higher peak occupant load during exhibition opening events. CO2 control and gentle perimeter flow.

Auditorium and lecture theatre. NCC Class 9b assembly at 100 to 500 seats. Speech-intelligibility focus drives NC-25 to NC-30 acoustic criterion. The supply diffusers are sized for low face velocity and the return is taken through the ceiling void.

Heritage house living and volunteer space. The 12 Sydney Living Museums properties, the National Trust portfolio in every state, the heritage volunteer-staffed houses across the country — Susannah Place, Vaucluse House, Elizabeth Bay House, Como House in Melbourne, Old Government House Parramatta, the Caroline Simpson Library and similar. Concealed HVAC routing through disused chimney flues, lath-and-plaster cavities and ceiling voids above the heritage plaster. Small-diameter spiral duct 80 to 200 mm on the SBFB-1500.

Gift shop and museum cafe. Commercial retail occupancy NCC Class 6 for the gift shop, commercial kitchen on NFPA 96 for the cafe. The gift-shop ventilation is a conventional retail outdoor-air rate plus the commercial-kitchen makeup for the cafe.

The Trove digital archive and digital preservation data centre. The NLA Trove platform, the NAA Records Continuum digital preservation system and the digital catalogue platforms operated by each State Library all require a TIA-942 ASHRAE TC 9.9 Class A1 environment for the data-centre infrastructure. The backup tape library (LTO 5, 6, 7, 8, 9 generations) sits in a separate cold-storage zone at the IPI media-storage envelope. The data-centre HVAC is on a separate plant from the collection-storage HVAC.

5. Heritage-interior concealed routing — museum gallery HVAC duct in significant fabric

A large fraction of the Australian collecting-institution building stock is itself heritage-significant. The State Library of NSW dates from 1826 with the Mitchell Library of 1910. The State Library of Victoria runs from 1856 with the La Trobe Reading Room dome completed in its current form in 1913. The Australian Museum 1827 building is the country's oldest natural-history museum. The Australian War Memorial 1941 building is on the National Heritage List. The Royal Exhibition Building Melbourne is on the UNESCO World Heritage List. The TMAG Davey Street Hobart building dates from the 1830s convict-era. Sydney Living Museums operates 12 historic Sydney houses. The National Trust of Australia operates a substantial portfolio of heritage properties in every state and territory. The HVAC engineer working in any of these envelopes operates under the Burra Charter 2013 and the relevant state Heritage Act (the NSW Heritage Act 1977, the Victorian Heritage Act 2017, the Queensland Heritage Act 1992, the Heritage of Western Australia Act 2018, the South Australian Heritage Places Act 1993, the Tasmanian Historic Cultural Heritage Act 1995, the ACT Heritage Act 2004 and the Northern Territory Heritage Act 2011), with the operative principles — do as much as necessary and as little as possible, retain significance, prefer reversible interventions, document everything — binding every duct routing decision.

The concealment strategy uses the existing voids that the original architecture provided rather than cutting new penetrations through significant fabric. The disused chimney flues from the original coal and gas heating systems of the 19th and early 20th centuries are the dominant concealed riser path; the cavity above the lath-and-plaster ceiling is the dominant horizontal trunk route; the under-floor void above the basement is the dominant secondary horizontal route; the original ventilation lay-light slots in the dome glazing of the heritage reading rooms are the dominant supply-air route into the protected interior; the cavity behind decorative timber wainscot and cornice mouldings carries the small-bore branch supply to the heritage diffusers; the original organ-loft riser and the bell-tower riser carry the trunk distribution where the building has them. The duct construction in these concealed routes uses small-diameter spiral on the SBFB-1500 (80 to 200 mm) for the branch supply and the SBSF-1525 stitchwelder for rectangular duct in the 100 to 300 mm depth band. Vibration must be decoupled at every support point because lath-and-horsehair plaster will crack at sub-audible vibration thresholds that an ordinary office system would never notice; neoprene-in-shear pads on every clip, spring isolators sized for fan loadings on every AHU and silencer assembly, no direct contact with original timber that may carry borer or fatigue damage, and no rigid fixings into dressed sandstone or lime mortar pointing.

The diffusers are heritage-compatible reproductions in cast iron, brass or bronze that match the original room's decorative scheme, rather than modern slot or linear diffusers. The heritage diffuser schedule itemises every diffuser with finish, profile, free area, bird-mouth depth and period reference, and the SBPC1500 plasma profiler cuts the custom plate fittings that adapt the modern duct geometry to the heritage diffuser face. The plant compound sits outside the heritage curtilage in a non-significant addition — a rear plant compound at grade, a roof plant deck on a non-significant adjacent wing, an undercroft below the heritage envelope, or a remote plant building connected to the heritage interior by a buried duct riser. The Statement of Heritage Impact (SOHI) prepared by the heritage consultant documents every metre of duct retained, removed, replaced or newly installed, photographs every penetration before-during-after, justifies every decision against the Burra Charter principles and accompanies the heritage consent application under the relevant state act.

6. The archive storage Bizot climate envelope and ISO 11799 compliance detail

The archive reserve stack is the most demanding HVAC zone inside a major collecting institution measured by year-round duty cycle. The gallery operates on a weekly cycle (open hours plus the cleaning and exhibition installation windows); the conservation lab operates on a weekday cycle (the conservator's bench hours); the reading room operates on a publicly-advertised access cycle; but the archive reserve stack operates 24 hours per day, 365 days per year, for the entire institutional life of the material. A failure of the archive HVAC envelope — a humidifier shutdown over a long weekend, a chiller failure during a heatwave, an outdoor-air damper jammed open during a bushfire smoke event — can produce fabric damage in a single incident that the institution then carries for the next 100 years.

The design response is dual redundancy on every critical plant element. Two air-handling units, two chillers, two boilers, two humidifiers, two dehumidifier banks, two filters per air path. Each unit sized so that a single unit can maintain the envelope during the cooler shoulder seasons, with the second unit cutting in for peak load and during planned maintenance. The fuel supply is dual; the electrical supply is dual on independent feeders with a standby diesel generator sized to carry the full archive plant for 72 hours; the BMS is dual with two independent controllers in hot-standby. The outdoor-air intake is high-MERV-filtered (MERV 13 to MERV 15) on the standing duty cycle and shifts to a gaseous-pollutant scrubbing mode during bushfire smoke events on a smoke-detection signal from the building management system or a manual override by the institution's facilities team. The outdoor-air intake itself is positioned away from prevailing vehicle traffic, away from any standby generator exhaust, and away from any other building exhaust that could short-circuit into the intake.

The duct distribution inside the archive reserve stack is SMACNA Class A leakage on the SBAL-V auto duct line, with the perimeter long-throw slot diffuser at the upper wall and the low-level return at the floor. The duct material is galvanised steel to AS 1397 Z275 for the general air path and 304 stainless on the branches that pass through the AS 4214 protected envelope where chloride exposure from the gaseous agent could attack galvanised material over the long term. The high-density mobile shelving (Compactus, Bruyne, Spacesaver Bracha) collapses 4 to 6 traditional fixed-shelf bays into a single mobile aisle bay, and the airflow strategy uses induced flow through the bay structure when the aisle opens, plus gentle convective recirculation when the aisle is closed. Each material class sits in a separate climate sub-zone — paper-dominant in one, photographic in a second, magnetic and optical media in a third, textile in a fourth — with each sub-zone independently controlled and independently monitored. The institution's collections management system (CMS) feeds the BMS the location of every object so that any local excursion can be correlated to the materials at risk.

The gaseous-pollutant load that the archive HVAC has to control includes the visitor and staff loading on CO2 (target less than 1,000 ppm even with low population density), formaldehyde from off-gassing of older timber shelving and legacy laminate (target less than the WES of 1 ppm STEL), VOCs from any solvent-based maintenance work in adjacent zones (paint, varnish, adhesive), the urban-background NOx and SO2 load that increases during winter heating season and during bushfire events (5 ppm STEL for NOx, 2 ppm STEL for SO2), the H2S background that causes silver tarnish on the photographic collections (10 ppm STEL), and the bushfire smoke PM2.5 that has become a dominant Sydney-Canberra-Melbourne-Adelaide design constraint over the December-to-March bushfire season since the 2019-2020 events (10 micrograms per cubic metre target, with the outdoor-air intake shifting to recirculation-plus-gaseous-scrub mode during peak smoke events).

7. The conservation lab fume cupboard exhaust — chemistry, materials and ducting

The conservation laboratory is the working point of the institutional conservation programme. The conservators carry out the cleaning, the consolidation, the restoration and the analysis of the collection material at the lab bench under the fume cupboard, the local exhaust ventilation hood, the microscope station, the X-ray fluorescence (XRF) analytical bench, the FTIR spectroscopy bench, the photographic documentation table and the wet-treatment sink. The fume cupboard exhaust is the dominant HVAC design constraint of the lab.

The Australian Standard AS 2243.8 Safety in Laboratories — Fume Cupboards sets the engineering requirement. Face velocity at the cupboard sash opening is 0.5 metres per second minimum for general conservation chemistry, with higher velocity for specialised activities (peracetic acid for textile sanitation, oxalic acid for paper conservation, hydrochloric acid for legacy print-etching and manuscript stabilisation). The exhaust ducting is dedicated, no sharing with general ventilation, no recirculation, and the discharge is at the roof above any building air intake by a minimum vertical separation set by the AS 1668.2 dispersion calculation. The duct material at the fume cupboard exhaust is 316L stainless on the SBAL-V auto duct line at 1.5 millimetre gauge, sized for the velocity requirement and with smooth internal joinery to minimise turbulence and condensation hold-up. The exhaust fan is a 316L stainless centrifugal in spark-resistant configuration with the impeller blade and the casing both in 316L. The continuous face-velocity monitor on the cupboard alarms if the velocity drops below the AS 2243.8 minimum, and the alarm interlocks with the building management system to flag the conservation team and the facilities team simultaneously.

The exhausted compounds include the full conservator solvent palette — acetone (WES 250 ppm), methyl ethyl ketone or MEK (WES 200 ppm), isopropanol or IPA (WES 400 ppm), ethyl acetate (WES 200 ppm), ethanol, white spirit and Stoddard solvent (WES 100 ppm), and the legacy toluene (WES 50 ppm STEL) that is being phased out across the Australian institutional sector. Alongside the solvents are the alkyd resin removers and varnish removers, the paint stripper, the ammonia-based cleaning solution (WES 25 ppm STEL), the oxalic acid for paper conservation, the peracetic acid for textile sanitation (WES 0.4 ppm STEL), and the occasional hydrochloric acid (WES 5 ppm STEL) for legacy print-etching and manuscript stabilisation work. The ozone background (WES 0.1 ppm) from UV sanitation lamps and from laser printers in adjacent zones is monitored separately. The chlorine background (Cl2 WES 0.5 ppm STEL) from legacy bleach restoration is also monitored. The hydrogen sulfide (H2S WES 10 ppm STEL) background that causes silver tarnish is monitored at the photographic conservation bench specifically.

A separate local exhaust ventilation (LEV) hood serves the conservation bench for solvent decanting, small-batch work and the documentation photography. The LEV hood is a captured-flow design with the capture plane at the bench surface, the exhaust velocity sized for the work envelope, and the ducting routed through the same 316L stainless system as the fume cupboard exhaust to the roof discharge. The supply air to the lab is HEPA H13 or H14 filtered to control particulate ingress that would compromise sensitive cleaning work, and the supply diffusers are positioned to avoid disturbing the LEV capture plane. The lab itself sits at 18 to 22 degrees Celsius and 45 to 55% RH, and the supply temperature is controlled to avoid any condensation on the cooler bench surfaces during high-humidity outdoor conditions.

8. Per-typology HVAC architecture — the major collecting-institution categories

The national library and the state library. The dominant zoning is the public reading room (NC-25 to NC-30 acoustic, 20 to 24 degrees Celsius, CO2 reset to less than 1,000 ppm), the rare-books and manuscripts room (16 to 18 degrees Celsius, 40 to 45% RH plus or minus 3%), the general reserve stack (16 to 18 degrees Celsius, 40 to 50% RH plus or minus 5%), the conservation laboratory (18 to 22 degrees Celsius, 45 to 55% RH with fume cupboard exhaust), the digitisation laboratory (20 to 22 degrees Celsius, ESD floor), the public gallery and exhibition space if the library operates one (Bizot envelope), the auditorium and lecture theatre (NC-25 for speech intelligibility), the staff office and back-of-house (general comfort), and the data-centre for the catalogue and digital preservation platform (TIA-942 ASHRAE Class A1). For the heritage library buildings — the State Library of NSW Mitchell Library, the State Library of Victoria La Trobe Reading Room, the National Library of Australia 1968 Bunning and Madden brutalist envelope (heritage in its own right under the ACT Heritage Act 2004) — the heritage-interior concealment strategy of section 5 applies, with the SBFB-1500 spiral and the SBSF-1525 stitchwelder doing the small-diameter concealed work.

The national archive and state archive. The dominant zoning is the reserve stack (16 to 18 degrees Celsius, 40 to 50% RH, high-density mobile shelving, gas suppression), the public reading room (20 to 24 degrees Celsius, NC-30, CO2 control, with the additional research-access protocol that the reading room operates under the federal Information Privacy Act and APP principles for donor and access records), the conservation and preservation laboratory (typical lab spec plus the additional capability for paper, photographic, magnetic-tape and digital-media preservation), the receiving and acquisition room (IPM quarantine), the digitisation and microfilming laboratory (rare in modern practice but retained for selected legacy collections), and the data-centre for the digital preservation platform. The NAA Records Continuum digital preservation system is hosted at a Class A1 data-centre with redundant infrastructure. The reading-room access workflow involves materials retrieval from the closed stack to the reader on demand, which generates a frequent air-lock and door-cycle pattern that the HVAC has to accommodate without compromising the reserve stack envelope.

The national museum and state museum. The dominant zoning is the public exhibition gallery (Bizot envelope, 200 to 2,000 visitor peak load), the temporary-exhibition gallery (Bizot envelope with the additional installation and de-installation cycle), the collection storage (Bizot or tighter depending on material), the conservation laboratory, the registrar and acquisition office, the curatorial office, the education and children's space (higher V_p, NC-35), the auditorium and lecture theatre, the gift shop and museum cafe (commercial retail and commercial kitchen), the atrium and foyer (high-volume assembly), the loading dock and art-handling bay (general industrial), and the back-of-house plant compound. The major regional museums — QAGOMA in Brisbane, NGV in Melbourne, MONA in Hobart, AGNSW in Sydney, WA Museum Boola Bardip in Perth, the South Australian Museum in Adelaide, MAGNT in Darwin, TMAG in Hobart — each carry their own building-specific architectural constraints. MONA Berriedale is built into the sandstone of the Berriedale peninsula and has a substantial below-ground envelope that complicates the supply-air intake and the exhaust discharge geometry. WA Museum Boola Bardip is the 2020 redevelopment integrating new gallery wings around the heritage Beaufort Street building. AGNSW added the Naala Badu (Sydney Modern) wing in 2022 with a Bizot-grade gallery envelope across the new building.

The national and state art gallery. The dominant zoning is the public exhibition gallery (Bizot envelope), the temporary-exhibition gallery (Bizot envelope plus installation cycle), the collection storage (Bizot or tighter), the conservation laboratory (typical lab spec), the curatorial and registrar offices, the education and children's space, the auditorium, the cafe and shop, and the loading dock. The NGA Sculpture Garden adds an outdoor display envelope with no climate control but with conservation-grade documentation, condition assessment and rotation back to indoor storage on a defined schedule. The NGA Aboriginal and Torres Strait Islander Galleries operate under the additional protocol with Traditional Owners on access, display and storage that the federal Aboriginal and Torres Strait Islander Heritage Protection Act 1984 supports. The National Portrait Gallery in Parkes operates as a portrait-focused gallery with comparable Bizot envelope and the additional photographic-portrait conservation requirement.

The audio-visual archive (NFSA). The dominant zoning is the nitrate-film cold-storage vault (4 to 10 degrees Celsius, 30 to 35% RH, flame-arrestor exhaust, INERGEN suppression), the acetate and polyester film vault (2 to 8 degrees Celsius, 25 to 30% RH), the digital-media and magnetic-tape archive (15 to 18 degrees Celsius, 30 to 40% RH), the audio playback and digitisation laboratory, the conservation laboratory for the film and sound media, the screening theatre and the public foyer, and the back-of-house plant. The Spielberg and Walsh holds at NFSA are nitrate-vault grade. The dedicated exhaust from the nitrate vault discharges through a flame-arrestor stack to the roof, the duct construction is welded 316L stainless on the SBAL-V line, the dampers are fail-closed on agent release, and the access protocol requires a permit-to-work signed by the Archive fire safety officer.

The Australian War Memorial and the memorial gallery. The dominant zoning is the heritage 1941 building with the Hall of Memory (heritage 1941 envelope, Bean's design, the Roll of Honour with the bronze name plates, the Tomb of the Unknown Soldier under the dome — concealed routing per section 5), the Anzac Hall (the 2001 addition with the large object display — aircraft, vehicles, larger ordnance), the various campaign and conflict galleries on the National Heritage List building, the conservation department (large-object and small-object conservation), the storage and reserve at the Treloar Conservation Centre at Mitchell ACT (a separate off-site repository of large objects under climate control), the auditorium, the research centre with the reading room and the collection database access, the cafe and shop, and the back-of-house plant. The AWM operates the Anzac Day Dawn Service in the forecourt with the Last Post Ceremony every evening, and the HVAC design accommodates the peak visitor load on those days plus the Saturday and school-holiday peaks.

The historic-house museum (Sydney Living Museums, National Trust properties). The dominant zoning is the heritage living rooms with original furniture, ceramic, textile, silver and wood (concealed HVAC routing through disused chimney flues and lath-and-plaster ceiling cavities, small-diameter spiral 80 to 200 mm on the SBFB-1500), the heritage kitchen with the original stove and the original chimney (NFPA 96 commercial-kitchen exhaust if the kitchen is operated for cooking demonstrations, otherwise mechanical ventilation only), the heritage cellar (12 to 15 degrees Celsius and 70 to 80% RH if used for wine storage, otherwise general heritage envelope), the volunteer staff room and the curator office (general comfort), and the small interpretive gallery and the gift shop. The 12 Sydney Living Museums properties — Hyde Park Barracks (UNESCO World Heritage), the Museum of Sydney, the Caroline Simpson Library, the Justice and Police Museum, Vaucluse House, Elizabeth Bay House, Susannah Place, The Mint, and the others — each carry property-specific heritage management plans that constrain the HVAC routing.

The heritage exhibition building (Royal Exhibition Building Melbourne). The 1880 Joseph Reed building, inscribed on the UNESCO World Heritage List in 2004 as the only purpose-built exhibition building from the Great Exhibition movement that remains in continuous service worldwide, sits at the highest tier of heritage protection. The HVAC envelope is divided between an exhibition floor on the assembly rate under AS 1668.2 and a series of climate-controlled microenvironments configured per exhibition for the loan-eligibility report. The trunk distribution is concealed in the existing roof void above the trefoil dome geometry, the supply is routed through the historic clerestory openings rather than through new penetrations, and the return is taken through the dome lantern at the apex. The duct construction is SBAL-V galvanised at SMACNA Class A leakage, the silencer casings are 304 stainless on the SB-ZF1500 stitchwelder, and the spiral feeder runs to the floor diffusers are SBFB-1500 stainless to match the architectural finish in the few locations where the duct is visible.

The conservation centre and Aboriginal cultural centre. The Aboriginal cultural centres and Indigenous art centres operate across the country in partnership with the major collecting institutions. The conservation centre brief combines the conservation laboratory spec with the cultural-protocol overlay that determines whether and how the material is displayed, accessed, stored and treated. The HVAC envelope itself is broadly the conservation lab and Bizot envelope spec, but the access protocol and the cultural-authority sign-off sit alongside the AICCM and the institutional protocol.

9. AS 4214 clean-agent fire suppression coordination for collecting institutions

The fire suppression strategy is the single most consequential decision the engineer makes for a national or state collection. A wet sprinkler discharge over irreplaceable cultural material produces water damage that is in many cases irreversible — a 19th-century manuscript, an oil-on-canvas panel painting, an Aboriginal bark painting, a colonial photographic print, a Federation-era nitrate film reel, a hand-coloured atlas plate, a leather-bound first-edition manuscript. The international consensus across ICOM, IIC, AICCM, the AIC and every major national collecting institution is that water-based suppression is unsuitable as the primary suppression system for the storage of irreplaceable collection material.

The Australian Standard AS 4214 Gaseous Fire Extinguishing Systems sets out the engineering requirements for the alternative. Four agents dominate the heritage and collection space. FM-200 (HFC-227ea, heptafluoropropane) is the legacy installation stock that dominated Australian gallery and archive suppression from the 1990s to the early 2010s. Novec 1230 (FK-5-1-12 fluoroketone) is the new-build preference on environmental and atmospheric-lifetime grounds — the global warming potential is approximately one and the atmospheric lifetime is approximately five days, compared with FM-200's GWP of approximately 3,500 and atmospheric lifetime of approximately 33 years. INERGEN (IG-541, a blend of 52% nitrogen, 40% argon and 8% carbon dioxide) is an inert-gas agent that extinguishes by reducing oxygen concentration to below combustion-supporting levels while keeping it within human-survivable bounds. Pure-nitrogen IG-100 is a pure-inert alternative in selected recent installations.

The HVAC duct designer's responsibility is the agent hold-time engineering. The protected enclosure has to maintain design agent concentration for the AS 4214 hold time (typically 10 minutes) after discharge, which means the supply and return duct dampers have to close to the protected zone on the same fire-detection signal that triggers agent release. The damper specification is fail-closed, with a fire-rated motorised damper at every supply and return penetration of the protected enclosure boundary, and the enclosure integrity is verified by a fan-pressurisation door-fan test on commissioning. The door-fan test measures the equivalent leakage area of the enclosure boundary at the AS 4214 test pressure, calculates the predicted hold time based on the discharged agent volume and the enclosure free volume, and signs off the system only if the hold time exceeds the AS 4214 requirement. Where the heritage agency requires a secondary water-based system for the very small fire that does not reach the gaseous-discharge detection threshold, an AS 2118 pre-action sprinkler is specified to charge only on a second-stage detection signal so the protected zone never carries water in the sprinkler pipework under normal conditions.

The detection system feeding the AS 4214 release is on AS 1670 Fire Detection and Alarm Systems, with very-early-smoke-detection (VESDA aspirating system) as the primary detection mode for high-value collection storage. The VESDA samples the protected enclosure air continuously and triggers the first-stage alarm at a smoke concentration well below the threshold of conventional point detection, giving the institution's facilities team and the conservation officer the opportunity to investigate before the system reaches the agent-release threshold. The second-stage detection triggers the agent release and closes the dampers; the third-stage detection (only in rare configurations) would trigger the pre-action sprinkler if the gaseous agent did not extinguish the fire.

The AS 1851 Routine Service of Fire Protection Systems compliance applies to every gaseous suppression system on a service interval of monthly visual inspection, quarterly functional test of detection and control circuits, annual functional test of agent-release valves and dampers, and a full system pressure test and weight check on the agent cylinders every 5 years for FM-200 and Novec 1230 and every 10 years for the inert-gas agents. The institution's facilities team and the maintenance contractor coordinate the schedule with the AICCM conservation officer to minimise the disruption to the protected enclosure during the service interval.

10. Bushfire smoke, urban pollution and the gaseous-pollutant load on the outdoor-air intake

Since the 2019-2020 bushfire season the bushfire smoke load on the outdoor-air intake has become a dominant design constraint for the major collecting institutions in Sydney, Canberra, Melbourne and Adelaide. The PM2.5 background during peak smoke events has reached more than 100 times the World Health Organization annual mean target, and the institutional outdoor-air strategy has shifted accordingly. The standing duty cycle remains a conventional MERV 13 to MERV 15 outdoor-air filtration plus a charcoal-bed gaseous-pollutant scrub at the major institutions. The high-smoke contingency shifts the outdoor-air damper position to minimum (typically 5 to 10% of design rate, sufficient to maintain CO2 control with the reduced occupant load during smoke events) and increases the recirculation fraction, with the recirculated air passing through the gaseous-pollutant scrub bed and the high-MERV filtration. The shift is triggered by the building management system on a smoke-detection signal from the outdoor-air intake, or by manual override by the institution's facilities team in response to the air-quality forecast.

The gaseous-pollutant scrub bed at the institutional intake removes the SO2, NOx, ozone, hydrogen sulfide and reduced-sulfur species that damage paper, textile and silver-photographic material at the urban background concentrations of the Australian capital cities. The scrub-bed media is potassium-permanganate-impregnated activated alumina for the oxidisable species, plus a separate activated-carbon bed for the VOC species. The scrub-bed effectiveness is monitored by inlet and outlet sampling on a defined interval, with media changeout when the outlet concentration approaches the design-target inlet concentration. The standing target inlet concentration to the protected zones is 1 ppb SO2, 1 ppb NOx, 1 ppb ozone and 0.1 ppb H2S, well below the WES and well below the threshold for accelerated degradation of the protected material.

The PM2.5 target is 10 micrograms per cubic metre at the protected-zone supply, which is achievable with MERV 14 plus a final HEPA H13 on the high-sensitivity zones (rare books, conservation lab supply, nitrate-vault makeup air). The visitor and staff loading on respirable particulate inside the public galleries is 4 to 8 milligrams per square metre per day of floor area as a typical visitor textile-fibre and human-dander load, which the gallery cleaning regime handles by a combination of low-speed walk-off matting at the entry, regular vacuum cleaning with HEPA-filtered equipment, and the gentle laminar supply that draws settling particulate downward rather than swirling it around the canvas surfaces.

11. Acoustic design for reading rooms, galleries and conservation labs

The AS/NZS 2107 acoustic criteria for the institutional zone types are: NC-25 for the reading room and the reading carrel and the specialist conservation laboratory and the auditorium speech zone; NC-30 for the gallery and the children's education space and the volunteer office; NC-35 for the gallery atrium and the cafe-adjacent public space; NC-40 for the back-of-house and the mechanical plant areas. The reading-room NC-25 criterion is the binding design constraint on the silencer specification and the duct velocity selection. The duct velocity in the reading-room supply is limited to 4 to 5 metres per second in the trunk and 2 to 3 metres per second at the diffuser branch, and an inline rectangular silencer is provided on every supply, return and exhaust trunk feeding the reading room. The SB-ZF1500 stitchwelder produces 304 stainless silencer casings around mineral-fibre baffles to NC-25 to NC-30 attenuation, and acoustic lining is provided on the first 6 to 9 metres of duct downstream of every fan with the mineral fibre face protected by an internal closed-face liner so no fibre sheds into the airstream.

For the heritage reading-room buildings — the SLV La Trobe Reading Room dome, the SLNSW Mitchell Library reading room, the NLA main reading room — the silencer geometry is constrained by the concealment envelope, and the silencer length is the dominant constraint on the trunk routing through the heritage void. The SB-ZF1500 stitchwelder produces the silencer casing to the available depth (typically 200 to 400 mm in the heritage cornice cavity, with a longer silencer in the under-floor void where depth is available), and the silencer baffle pitch is selected to deliver the required attenuation within the available length. Vibration isolation at the silencer support is critical because the lath-and-plaster ceiling will crack at sub-audible vibration thresholds; neoprene-in-shear pads on every clip, with spring isolators on the heavier silencer casings.

12. SBKJ machinery configuration for the institutional ductwork portfolio

The duct production machinery that fabricates the institutional HVAC ductwork breaks down by zone, material and gauge as follows. We have written this section as a working reference for the SBKJ machine schedule on a typical Australian national-library, national-museum, national-archive or national-gallery project, with the same configurations applying at proportionally reduced scale to the state-level and regional projects.

The SBAL-V auto duct production line handles the bulk of the rectangular distribution. On galvanised steel coil to AS 1397 Z275 at 0.8 to 1.2 millimetre gauge, the SBAL-V produces TDF-flanged duct in the 200 to 1,500 millimetre band with SMACNA Class A leakage on tested installations. The same line is reconfigured for 304 stainless coil at 1.2 millimetre gauge for the conservation laboratory general exhaust trunk and for any zone with elevated chloride exposure (the heritage cellar, the wet-treatment sink exhaust, the photographic conservation darkroom exhaust). The line is reconfigured again for 316L stainless coil at 1.5 millimetre gauge for the fume cupboard exhaust trunk, the nitrate-vault exhaust, the dangerous-goods cabinet exhaust and the chloride-exposed paths around clean-agent suppression where the suppression agent decomposition products on a long-duration discharge could attack a lower grade.

The SBFB-1500 spiral tubeformer handles the small-diameter concealed routing that the heritage interior demands. The 80 to 200 millimetre spiral band fits through the disused chimney flues, the lath-and-plaster ceiling cavities, the cavity above the dome glazing, the cavity behind the heritage cornice and the original organ-loft riser. The machine produces galvanised spiral for the general concealed routing and 304 stainless spiral for the heritage gallery branches and the heritage cellar branches. The machine's small-diameter capability is the differentiator for heritage work — many spiral tubeformers in the Australian market start at 200 to 250 millimetre minimum, which excludes them from the genuine heritage concealment envelope.

The SBSF-1525 stitchwelder handles the small-rectangular and small-round work that complements the SBFB-1500. The 100 to 300 millimetre rectangular band fits the heritage cornice cavity and the lath-and-plaster ceiling void. The machine produces galvanised and 304 stainless work and is the primary machine for the heritage diffuser approach duct that adapts the modern distribution geometry to the period-correct diffuser face. The SB-ZF1500 stitchwelder is the equivalent for stainless plenum and silencer casings up to 1,500 millimetre, and the larger SBSF-1525 produces longer-length work up to 1,525 millimetre.

The SB-ZF1500 stitchwelder produces the 304 and 316L stainless plenum casings and silencer assemblies for the NC-25 reading room and the NC-25 conservation lab silencer schedule. The machine's continuous-seam-weld capability handles the silencer casing leakage requirement that the reading-room acoustic specification demands, and the same machine produces the fume cupboard inlet plenum and the LEV hood transition that the conservation lab requires.

The SBPC1500 plasma profiler cuts the custom plate fittings — the fume cupboard transitions, the nitrate-vault flame-arrestor stack, the heritage diffuser bird-mouth profiles, the duct-to-AHU transitions, the silencer transitions and the spiral-to-rectangular transitions. The 1,500 by 3,000 millimetre table handles the typical plate size for institutional fittings, and the machine cuts galvanised, 304 stainless and 316L stainless plate to the required tolerance.

The SBLR-600 longitudinal welder produces the NFPA 96 black-steel commercial-kitchen exhaust for the museum cafe and the museum restaurant. The 16-gauge welded black-steel duct on the SBLR-600 carries the grease-laden vapour from the Type I hood through the continuous fire-rated wrap to the upblast roof fan with UL-300 wet-chemical fire suppression at the hood. The same welder produces the high-temperature exhaust for the thermal pest-treatment chamber operating at 50 degrees Celsius during the IPM quarantine cycle.

The SBTF-1500, SBTF-1602 and SBTF-2020 close-coupled tubeformer family handles the wider-band spiral up to 2,000 millimetre for the main supply trunks in the larger institutional projects — the National Library main building trunk, the National Gallery main building trunk, the Anzac Hall trunk at the Australian War Memorial, the QAGOMA Gallery of Modern Art trunk, the NGV International trunk. The close-coupled architecture produces a more compact spiral with tighter helix geometry than the open-frame machines, which matters for the institutional trunk because the architectural drawing often constrains the spiral diameter to a defined plenum depth.

The full machine schedule for a typical national-tier institutional project is therefore: SBAL-V on galvanised for general distribution, SBAL-V on 304 stainless for conservation exhaust and heritage cellar, SBAL-V on 316L stainless for fume cupboard and nitrate-vault, SBFB-1500 spiral for heritage concealed routing 80 to 200 millimetre, SBSF-1525 stitchwelder for heritage rectangular concealment and diffuser approach duct, SB-ZF1500 stitchwelder for stainless silencer and plenum casings, SBPC1500 plasma for custom plate fittings, SBLR-600 longitudinal welder for NFPA 96 commercial kitchen and 50 degrees Celsius thermal treatment exhaust, SBTF-1500 to SBTF-2020 spiral for main trunk up to 2,000 millimetre. The same schedule applies at proportionally reduced scale to state and regional projects, with the smaller projects typically running the SBAL-V plus the SBFB-1500 plus the SB-ZF1500 as the core machine set.

13. AS 1668.2 outdoor-air rates and demand-controlled ventilation per zone

The AS 1668.2 outdoor-air rate per zone applies as follows. Gallery and exhibition assembly: V_p 10 L/s per person plus V_a 0.5 L/s per square metre, with the design rate being the greater of the two. Reading room and reading carrel: V_p 10 L/s per person plus V_a 0.5 L/s per square metre, with CO2 reset to maintain less than 1,000 ppm in the breathing zone and a design tolerance to 1,500 ppm during weekend and school-holiday peak. Archive reserve stack: V_a 0.5 L/s per square metre (low population, the rate is area-dominated). Conservation laboratory: V_p 12 L/s per person plus the AS 2243.8 fume cupboard makeup plus the LEV makeup. Auditorium and lecture theatre: V_p 10 L/s per person plus V_a 0.5 L/s per square metre with CO2 reset. Gift shop NCC Class 6 retail: V_p 5 L/s per person plus V_a 0.5 L/s per square metre. Cafe and museum restaurant: V_p 10 L/s per person plus commercial-kitchen makeup. Children and education room: V_p 12 L/s per person with higher CO2 sensitivity (target less than 800 ppm). Toilet exhaust 25 L/s per pan minimum. The total outdoor-air rate is the sum of all the zone rates plus the unsharable exhaust makeup, with the ventilation effectiveness factor applied per AS 1668.2.

Demand-controlled ventilation (DCV) on CO2 sensors is standard practice across the major Australian institutions. The CO2 sensor density is one per 200 square metres of floor area in the public zones, with the outdoor-air damper position resetting to maintain CO2 below the design setpoint. The morning warm-up cycle starts 2 to 3 hours before public opening to bring the gallery and reading room to setpoint without imposing a draught on the protected fabric, and the evening setback maintains the Bizot envelope on the protected zones throughout the closed period. The DCV reset is integrated with the BMS and the building energy-management strategy, with the institutional facilities team monitoring the trend data to identify any drift in the CO2 setpoint or the outdoor-air damper position that might indicate a sensor calibration drift or a damper actuator fault.

14. Coordination with the heritage management plan and the Burra Charter sign-off

The heritage management plan (HMP) is the institutional document that consolidates the heritage values of the building and prescribes the conservation policies that apply to any intervention. Every major Australian collecting institution operating in a heritage envelope has an HMP that the institution's facilities team and the project consultant team apply to every HVAC project. The HMP itemises the significant fabric, the significance of each element, the acceptable interventions, the prohibited interventions and the documentation requirements. The HVAC engineer's design decisions feed into the Statement of Heritage Impact (SOHI) that the heritage consultant prepares for the consent application under the relevant state heritage act.

The Burra Charter sign-off on the duct design follows the standard sequence. The heritage consultant reviews the duct shop drawings and the routing alignment against the HMP. The institutional conservation officer reviews the environmental class delivery against the conservation requirements for the protected collection. The facilities team reviews the maintenance access and the long-term operational implications. The state heritage council reviews the consent application against the state act. The Australian Human Rights Commission reviews any AS 1428.1 DDA accessibility exemption request for heritage fabric that cannot be modified. The SOHI documents every metre of duct retained, removed, replaced or newly installed, photographs every penetration before-during-after, justifies every decision against the Burra Charter principles and accompanies the consent application. Approval typically takes 3 to 12 months for a state-listed building and 12 to 24 months for a UNESCO World Heritage site such as the Royal Exhibition Building Melbourne.

15. Commissioning, handover and long-term operational monitoring

The commissioning phase delivers the final compliance evidence that the institutional facilities team and the AICCM conservation officer require for the sign-off and the loan-agreement certification. The commissioning sequence is: pressure-test every duct section to SMACNA Class A leakage at 250 Pa, with the test results recorded per duct section; verify the AS 4214 hold-time on every gaseous-suppression-protected enclosure by a fan-pressurisation door-fan test; verify the fume cupboard face velocity on every laboratory hood at the AS 2243.8 minimum across the cupboard sash range; measure NC at three positions in each public and conservation zone with the system at full design flow; measure CO2 in the gallery and reading-room breathing zone over a simulated full-occupancy cycle; measure temperature and RH at the gallery floor and at every archive bay across a 7-day continuous logging period; verify the Bizot rate-of-change tolerance over 24-hour and 72-hour windows; record visible-light and UV at every gallery display station; record gaseous-pollutant concentration at the protected-zone supply for the standing duty cycle and for the smoke-event contingency. The sign-off requires all criteria within tolerance, plus the AICCM conservation officer's environmental compliance certificate and the heritage consultant's Burra Charter certificate for any heritage-interior work.

The handover documentation comprises the full mechanical-services O&M manual, the duct shop drawing record set with every modification annotated, the commissioning data set in machine-readable form for the BMS historical trend integration, the heritage SOHI photographic record, the AICCM environmental-class certification, the AS 4214 hold-time test report, the SMACNA leakage test report per duct section, the fume cupboard face-velocity test report per laboratory hood, the gaseous-pollutant scrub-bed media changeout schedule and the long-term operational monitoring plan. The institutional facilities team and the AICCM conservation officer use the long-term monitoring plan to track the environmental envelope across the seasons, identify any drift early and respond before the drift produces fabric damage.

The 12-month seasonal log provided at handover documents the temperature, RH and CO2 trend in every zone across the full annual cycle, with the bushfire smoke contingency response logged separately for any event that occurs in the first year of operation. The institution and the heritage consultant review the log at the 12-month mark and the consultant signs off the long-term Burra Charter compliance certificate for the heritage interior. The AICCM conservation officer reviews the log against the loan-agreement environmental envelopes and certifies the institution as compliant for the international loan programme for the following year. The cycle then repeats annually for the operational life of the building.

16. The SBKJ commitment to the Australian collecting-institution sector

SBKJ Group has built the duct production machinery for projects in this sector over three decades, working with the mechanical-services contractor and the institutional facilities team on national-tier, state-tier and regional-tier projects across every Australian jurisdiction. Our Box Hill North office in Victoria carries the engineering, the after-sales service and the spare-parts inventory for the SBAL-V auto duct line, the SBFB-1500 spiral tubeformer, the SBSF-1525 stitchwelder, the SB-ZF1500 stitchwelder, the SBPC1500 plasma profiler, the SBLR-600 longitudinal welder and the SBTF-1500 to SBTF-2020 close-coupled tubeformer family that fabricates the duct described in this guide. Our engineering team has worked with the mechanical-services contractor on the institutional projects from the early stage when the SOHI is being drafted through to the commissioning and the post-handover seasonal log review. We see the AICCM-accredited conservators, the institutional facilities engineers, the heritage consultants and the mechanical-services contractors as parts of the same delivery team, and our machine specifications are designed to feed the duct shop economically and to the institutional specification.

We will be exhibiting at ARBS 2026 at the International Convention Centre Sydney in May 2026 alongside the broader Australian HVAC and mechanical-services industry. The SBKJ stand at ARBS 2026 will demonstrate the SBAL-V auto duct production line, the SBFB-1500 spiral tubeformer and the SBSF-1525 stitchwelder configurations for the collecting-institution sector, and our engineering team will be available for consultations on machine specification, duct material selection and project-specific configuration for the institutional projects in the project pipeline across the country. Our Australian Ducting Pty Ltd entity carries the front-of-house presence for the trade-show audience, and the SBKJ engineering team out of Box Hill North supports the project consultations and the post-show follow-up.

For a project consultation, a machine specification quotation or a duct-production capacity assessment for a national library, state library, national archive, national museum, state museum, national gallery, state gallery, conservation laboratory or cultural-heritage collection project, contact SBKJ Group at sales@sbkjduct.com or +61 435 074 994. Our website at sbkjduct.com carries the full machine specifications, the case studies and the technical reference library. We look forward to working with the Australian collecting-institution sector on the next generation of duct production for the country's irreplaceable cultural heritage.

Contact — SBKJ Group

SBKJ Group — Box Hill North, Victoria.
Email: sales@sbkjduct.com
Phone: +61 435 074 994
Web: sbkjduct.com
Exhibiting: ARBS 2026, ICC Sydney, May 2026.
Australian Standards focus — AS 1668.2 ventilation, AS 4254 ductwork construction, AS 1530.4 fire resistance, AS 1851 maintenance, AS 4214 gaseous suppression, AS 2118 sprinkler, AS 1670 detection, AS/NZS 2107 acoustic, AS/NZS 3666 microbial, AS 2243.8 laboratory fume cupboard.
Reference frameworks — ASHRAE Applications Handbook Chapter 21, Bizot Group climate envelope, ISO 11799 archive storage, BS 5454 library and archive storage, ISO 18934 IPI media storage, the AICCM Australian Institute for the Conservation of Cultural Material guidance, ICOM International Council of Museums, IIC International Institute for Conservation, AIC American Institute for Conservation, IPI Image Permanence Institute, the Burra Charter 2013, the Aboriginal and Torres Strait Islander Heritage Protection Act 1984, the state Heritage Acts of NSW, VIC, QLD, WA, SA, TAS, ACT and NT, and the UNESCO World Heritage Convention.

SBKJ Engineering Team. Box Hill North, Victoria. May 2026.