NDIS SDA High Physical Support, Robust, Improved Liveability, Fully Accessible & SIL Group Home HVAC Ductwork Guide

Why a second SDA HVAC guide

The original SBKJ NDIS Specialist Disability Accommodation HVAC Ductwork Guide walks a procurement lead, a mechanical engineer or a developer’s project manager from first principles of the SDA Design Standard 2019 through to a defensible HVAC specification. That guide answers the question, “what is SDA and how do I write a compliant mechanical brief?”

This guide answers a different question: “I have my SDA enrolment category locked, my dwelling has these specific rooms in this specific configuration, my residents will use these specific medical and assistive technologies, and the operator is layering Supported Independent Living service on top — how do I detail the ductwork room by room?” It is the field reference an SBKJ engineer walks through with a sheet metal contractor sizing a particular dwelling, not the policy overview a developer reads before tender. Both guides should be read together — this one assumes the SDA Design Standard 2019, the 2024 update, the AS 1668.2 outdoor air rates and the four enrolled categories are already familiar.

Within the dwelling envelope, the rooms that drive the HVAC scope are not the standard living-and-bedroom layout of a typical residential build. SDA dwellings carry medical and supply storage, sluice rooms, sensory rooms, hydrotherapy interfaces, sleepover carer rooms, communications and emergency-response control rooms, wash bays for resident wheelchairs, modified-vehicle transport bays, and backup generator enclosures — each with its own ventilation and acoustic brief. Group home dwellings under Class 1b layer commercial kitchen and commercial laundry obligations on top of residential plant. SIL service delivery layers continuous staff occupancy on top of resident occupancy. The job of the duct contractor is to integrate all of this into a single coherent mechanical package without the ceiling void running out of room.

The four enrolled SDA design categories at field-detail depth

Where the introductory guide describes the four enrolled SDA design categories at concept level, this section walks each category through to the duct-contractor field detail. The categories drive different grille selection, different fixing schedules, different plant duty cycles and different commissioning evidence.

High Physical Support (HPS) — Category 4

High Physical Support is the highest enrolled SDA design category. It serves residents with very high physical support needs, including residents with quadriplegia and tetraplegia from spinal cord injury at the C5 level or above, residents with acquired brain injury (ABI) requiring intensive 24/7 care, residents with motor neurone disease (MND), residents with late-stage multiple sclerosis (MS), residents with high-level cerebral palsy and residents who use mechanical ventilation or non-invasive ventilation (CPAP, BiPAP) on a continuous or near-continuous basis. The dwelling is built to a higher specification than any other SDA category because the residents cannot self-evacuate and cannot self-rescue from a thermoregulatory emergency.

The HVAC brief at field depth has six category-specific moves. First, ceiling hoist coordination. The HPS dwelling has a structural ceiling-mounted hoist track typically running from the bed in the primary bedroom, through the doorway to the ensuite, to the roll-in shower and the accessible toilet. The track is bolted to structural ceiling beams, runs straight or with curve sections, and demands a clear envelope underneath of at least 2.4 m and a clear envelope above of at least 100 mm for the track carriage. This envelope is exactly where, in a typical residential dwelling, the HVAC engineer would run the supply duct to the bedroom diffuser. Field detail: route the supply through service bulkheads at the corner of the ceiling void, use rigid flat-profile duct (not flex) at any necessary crossing of the hoist track, locate the bedroom supply diffuser at the bedhead wall and the opposite wall rather than over the bed, and locate the ensuite exhaust grille on the long wall rather than over the shower roll-in area.

Second, individual climate control with a wide working band. The HPS primary bedroom must hold a setpoint anywhere from 18 to 26 degrees C with a tight 0.5 degree C deadband. The wide working band is not a comfort preference; it is a clinical requirement. Residents with high spinal cord injury lose autonomic control of sweating and skin vasodilation below the level of injury, residents with MS experience worsening neurological symptoms above approximately 25 degrees C (Uhthoff’s phenomenon), and residents on certain medications have impaired temperature regulation. The HVAC engineer sizes the cooling capacity to maintain 18 degrees C on a 40 degrees C ambient design day and the heating capacity to maintain 26 degrees C on a 0 degrees C ambient design day, with a 10 percent safety margin on cooling.

Third, redundant reverse-cycle circuits. The HPS dwelling typically requires two independent reverse-cycle systems — a primary system serving all habitable rooms, and a secondary system serving at least the primary bedroom and the ensuite. The redundant system can share ductwork up to a motorised changeover damper but must run from a separate condenser, separate electrical circuit and separate refrigerant line set. The redundant system must be acoustically acceptable on its own (NC 25 in the primary bedroom) because it gets used for routine bedroom conditioning when the primary system is in service, not just for emergency redundancy.

Fourth, ventilation continuity at 10 L/s per person. HPS residents are continuous-occupancy at a scale beyond any other SDA category. AS 1668.2’s 7.5 L/s per person residential rate is the floor; SBKJ engineers size HPS outdoor air at 10 L/s per person and provide a small, separately powered transfer-air fan to maintain background ventilation during plant cycling. The elevated rate also manages CO2 build-up from oxygen concentrators (which raise room CO2 because they concentrate oxygen from atmospheric air, displacing nitrogen and rebreathing CO2), positive pressure ventilators and CPAP humidifiers running 24/7.

Fifth, integration with backup power. Many HPS residents use life-critical equipment — invasive or non-invasive mechanical ventilation, suction units, oxygen concentrators, IV pumps, electric profile beds with pressure-mapping cycles. A power outage that takes out the air conditioning during a 40 degree heatwave is a clinical emergency. The dwelling typically has a battery storage system sized for the life-critical load (excluding the air conditioning) plus a backup diesel or LPG generator sized for the full load including the primary HVAC. The HVAC engineer must coordinate transfer switch operation, generator radiator extract, and the brief electrical interruption during transfer that may briefly trip the indoor unit.

Sixth, assistive-technology coordination. Beyond the hoist track, the HPS dwelling integrates environmental control units (ECUs), smart-home control of doors and curtains, voice-activated systems, eye-gaze controlled environmental devices, emergency response IT, and increasingly home-based telehealth video infrastructure. None of these is the HVAC scope, but the HVAC ductwork is competing for the same ceiling void, the same service riser and the same control hardware. HVAC must be in the BIM model at concept design.

Robust (R) — Category 3

Robust is the SDA category for residents whose disability is associated with complex behavioural support needs — including residents on the autism spectrum with severe aggression or self-injurious behaviour, residents with anxiety disorders presenting as destructive behaviour, residents with severe intellectual disability and complex needs and residents whose behaviours of concern have, in the past, damaged building fabric, fixtures, fittings or services. The dwelling is built to a heavier-duty specification than any other category, oriented around dignity, safety and durability.

The HVAC brief at field depth is dominated by vandal-resistance, ligature-resistance and tamper-resistance. Vandal-resistant grilles are 304 stainless steel or heavy-gauge powder-coated steel with welded security mesh inserts. The mesh is welded to the grille frame, not clipped in, and cannot be removed without tools. Impact-rated diffuser fixings rated for 90 J impact — five times the standard residential rating — are typical on linear bar grilles and anti-ligature swirl diffusers. Anti-ligature means no opening, slot or fixing allows a resident to attach a cord, fabric strip or other ligature. Bar grilles are specified with closely spaced or angled bars; swirl diffusers are specified with anti-ligature blade geometry; concealed return-air pathways are preferred over visible return grilles.

Tamper-resistant fixings are one-way screws, pin-Torx, square-drive, or hex-pin-key fixings that cannot be opened with improvised tools. The lockable ceiling access hatch for filter replacement uses a square-drive or hex-pin-key lock, not a screw or a slip latch. The filter housing itself is in the ceiling void, not on a wall where it is visible and reachable. Wall-mounted controls are minimised. Robust dwellings typically use a single secure thermostat in a locked control cabinet, with resident-facing temperature adjustment limited to a 21-24 degrees C range to prevent rapid setpoint cycling that strains the plant. The cabinet uses one-way screws and a tamper-evident seal.

Anti-pick wall penetrations — every duct, refrigerant pipe, conduit or services penetration through a resident-accessed wall — is sealed with intumescent mastic and a metal escutcheon plate fixed with tamper-resistant screws. Soft-set silicone sealant alone is not acceptable; residents will pick it out. Concealed duct routing through bulkheads or service voids is preferred over exposed ducts on resident-accessed ceilings. Where exposed ducts cannot be avoided, the duct construction is impact-rated and the seams are continuous-welded rather than slip-and-drive or TDF flanged, because TDF cleat ends in resident reach create handholds.

The duct construction itself stays galvanised steel to AS/NZS 4254.2 for general supply and return service, but with the impact-rated grille terminations and the vandal-resistant returns the duct contractor specifies 304 stainless steel for the terminal sections and fabricates these on the SBKJ SB-ZF1500 stitchwelder. Bathroom and kitchen exhaust risers are aluminium or stainless steel because of the continuous high-humidity service. Joints in exposed locations (risers accessible to residents) are sealed and concealed — no exposed slip joints, no exposed flex duct collars at low level.

Improved Liveability (IL) — Category 1

Improved Liveability is the entry-level enrolled SDA category. It serves residents with sensory disability (severe vision or hearing impairment), chronic mental illness affecting daily function, intellectual or cognitive impairment, or sensory processing differences associated with autism spectrum. The design priority is calmer, more predictable, more controllable environments with reduced sensory load, clearer wayfinding and softer surfaces.

The HVAC brief at field depth is dominated by acoustic discipline. NC 30 to 35 is the working brief in common areas; NC 25 to 30 in bedrooms. Achieving these targets reliably in a residential-scale build requires the same disciplines used in private hotel suites. The indoor unit is located in a service cupboard or corridor ceiling void rather than over the bedroom. A sound-attenuator lined plenum at least 600 mm long sits immediately downstream of the indoor unit, sized so face velocity drops below 3 m/s. An acoustic flexible duct connection at least 1.5 m long sits between the indoor unit and the first rigid section to break structure-borne paths. Main duct velocity is at or below 4 m/s through any branch serving a bedroom. Branch velocity is at or below 3 m/s at the diffuser take-off. Supply diffuser face velocity is at or below 2 m/s. The return grille is at least 1.5 m from the bedhead.

The SBKJ engineering approach is to specify the lined plenum and sound attenuator as 304 stainless steel with perforated face plates, fabricated on the SB-ZF1500 stitchwelder, when the dwelling also has Robust crossover requirements (sensory disability is common in residents with complex behavioural support needs, so IL+R blended specifications are routine in shared SDA dwellings). For pure IL dwellings, galvanised lined plenum is acceptable.

Beyond pure acoustic discipline, IL drives predictable airflow patterns — diffusers placed to avoid direct draughts on seated or recumbent residents, no high-velocity throw across the bed, no abrupt cycling of the indoor unit (modulating-fan units preferred over single-speed), and a soft-touch large-button bedhead controller that does not require fine motor adjustment. Visual displays should be glare-free with adjustable backlight, because residents with sensory processing differences may experience standard LED displays as overwhelming.

IL also drives visual alarm coordination. AS 1428.5 covers communications for hearing-impaired residents, and the visual alarm beacon in the resident bedroom and the bathroom must coordinate with the HVAC ceiling layout. The beacon location, viewing angle and ceiling clearance are architectural decisions but the HVAC engineer must avoid placing a diffuser directly under or directly opposite the beacon where ceiling shadowing would block the field of view.

Fully Accessible (FA) — Category 2

Fully Accessible is the SDA category for residents with significant physical impairment, including most full-time wheelchair users, residents with high-level paraplegia, residents with bilateral lower-limb amputation, and residents with severe muscular dystrophy. The dwelling is designed for independent or low-assistance living: kitchen benches at adaptable heights, fully accessible bathrooms with roll-in showers, level thresholds throughout, switches and controls within reach from a seated position, and corridors and doorways sized for power-wheelchair manoeuvring.

The HVAC brief at field depth introduces three category-specific moves. First, AS 1428.1 reach range — all user-operated controls (wall-mounted thermostats, ventilation switches, remote receiver locations) are at 900 to 1100 mm above finished floor level with no obstructing furniture or fittings. Second, high-level return air — return-air grilles are not at ankle height where they can be obstructed by mobility equipment, footplates, trailing oxygen tubing or wheelchair-mounted ventilator cabling. High-level return is preferred, with the return path sized for the design airflow without creating a wall or sub-floor cavity that conflicts with grab-rail back-blocking. Third, transfer-zone diffuser placement — the diffuser layout avoids direct discharge onto transfer zones (bed-side area where a resident transfers from wheelchair to bed, the bathroom transfer point and the toilet) because thermal comfort during a slow, assisted transfer is very different from comfort while seated.

FA dwellings also typically use Livable Housing Design Gold or Platinum as the design overlay. Platinum drives larger bathrooms (often 4 m² or more clear floor space), wider corridors, and additional clear-space allowances around fittings. The HVAC engineer must coordinate diffusers, returns and exhaust grilles with these geometries — particularly avoiding grilles directly above a roll-in shower, where condensation drip onto a non-slip floor creates a serious slip risk. The accessible kitchen has a roll-under hob and a roll-under sink; the rangehood is at a lower mounting height to be reachable, and the kitchen exhaust riser is sized for the AS 1668.2 residential minimum with boost activation.

The room-by-room HVAC playbook for SDA, SIL and group home dwellings

Beyond the four design categories, the duct contractor on an SDA, SIL or group home project encounters a set of specific rooms that drive the bulk of the mechanical scope. This section runs each room in field-detail order.

Resident bedroom

The resident bedroom is the unit cell of an SDA dwelling and the most occupied room in the building. The resident is in the room 14 to 18 hours a day during sleep and rest, with daytime occupancy at varying levels depending on the resident’s functional capacity. In HPS dwellings, residents may be in the bedroom for the entire 24-hour day, with support workers attending in shifts.

The bedroom HVAC specification is: outdoor air at 7.5 L/s per person in IL and FA, 10 L/s per person in HPS, continuous; individual setpoint control at the bedhead with simple soft-touch interface; working setpoint range 20-26 degrees C in IL and FA, 18-26 degrees C in HPS, locked 21-24 degrees C in Robust; relative humidity 40-55 percent; NC 25 in HPS primary bedroom with redundant circuit running, NC 25-30 in IL bedroom, NC 30 elsewhere; MERV 13 minimum filtration at the indoor unit return, MERV 14 in HPS where the resident uses non-invasive ventilation or has a tracheostomy.

The bedroom supply diffuser is on the long wall away from the bed, with throw directed across the room rather than at the bedhead. The bedroom return is high-level on the opposite wall or in the ceiling near the doorway, at least 1.5 m from the bedhead. The ensuite door is undercut by 20 mm or has a transfer grille to maintain pressure cascade from bedroom to ensuite. The bedroom is at slight positive pressure relative to the ensuite and slight positive pressure relative to the corridor. SBAL-V galvanised supply duct, SBSF-1525 round flange on any spiral return riser, SBLR-600 flexible duct connector tail at the indoor unit.

Common kitchen — group home and shared SDA

Group home and shared SDA dwellings have a common kitchen serving 3 to 8 residents plus support workers. The kitchen typically runs cook-serve production for resident meals with batch cooking for some meals, plus snack and beverage preparation continuously. Some dwellings have a therapeutic kitchen for resident participation in meal preparation.

The kitchen HVAC scope depends on whether the dwelling is enrolled as Class 1a (single-family-equivalent kitchen — residential rangehood with ducted riser) or Class 1b (small boarding-style with commercial kitchen-grade exhaust hood) or Class 2/9c (full commercial kitchen exhaust). For Class 1b group homes serving 6 to 8 residents the kitchen is borderline — many councils require a commercial rangehood with 304 stainless exhaust duct to AS 1668.1, and the duct contractor should confirm the specific local authority requirement at concept design.

The kitchen exhaust riser, where commercial grade, is 304 stainless steel with continuous welded longitudinal seams (not slip-and-drive), routed through a fire-rated shaft to a roof-mounted high-velocity discharge fan. Cleanout doors at every change of direction and at maximum 4 m intervals on horizontal runs. The duct contractor fabricates the riser on the SBKJ SB-ZF1500 stitchwelder with SBSF-1525 round flange terminations. Spark-resistant aluminium terminal on the LPG bottle storage exhaust where the kitchen runs on LPG (common in regional SDA without reticulated gas). See the SBKJ Commercial Kitchen Exhaust HVAC Duct Guide for the full kitchen exhaust scope.

Common dining and lounge

The common dining and lounge serve all residents and support workers at meal times and during socially active hours. Dining is the peak-occupancy moment — 6 to 8 residents plus 2 to 4 support workers during meal service, with wheelchairs taking more floor area than typical residential seating. The lounge is the daytime social heart with quieter occupancy patterns.

The dining and lounge HVAC specification is: outdoor air at AS 1668.2 10 L/s per person for shared common rooms; setpoint range 21-25 degrees C; NC 35 acoustic in the dining, NC 30-35 in the lounge; supply diffuser placement avoiding direct discharge on residents in wheelchairs or recliners; deliberately spread throw at low velocity. The kitchen-to-dining interface is critical — the dining is at slight positive pressure relative to the kitchen so cooking smells do not migrate. Where the dining and lounge are open-plan, a single zone with a single thermostat is acceptable; where they are separated by a partition, separate zones with individual setpoint are preferred.

Resident bathroom and en-suite

The accessible resident bathroom and en-suite has a roll-in shower (no threshold, level-access floor drainage), accessible WC with grab rails and a transfer area, accessible basin with knee clearance for seated use, and an overhead ceiling hoist track in HPS dwellings running into the shower. Heated towel rails are standard for comfort and for drying linen quickly.

The bathroom exhaust specification is: AS 1668.2 minimum 25 L/s on the WC with the local exhaust grille located directly above the WC; 30 L/s on the accessible roll-in shower with the grille located on the long wall outside the shower throw area (not over the roll-in zone where condensation drip is a slip risk); continuous low-speed background extract at 8-10 L/s per bathroom with boost activation on humidity or manual switch; heated towel rail extract continuous at 3-5 L/s background to manage moisture from drying linen. The bathroom exhaust riser is aluminium for IL and FA dwellings, 304 stainless for Robust and HPS dwellings. The cowl at roof is weatherproof with a low-resistance bird guard. SBKJ specifies the riser fabricated on the SBAL-V auto duct line in the appropriate material with SBSF-1525 round flange terminations.

Carer and staff station

The carer or staff station is the central operational point for the support team. In a group home it is typically a small room or open-plan workstation adjacent to the main living area. In an SDA dwelling the staff presence varies — Improved Liveability dwellings may have intermittent support, while HPS dwellings are continuously staffed. The room hosts a medication storage cabinet (drug safe), a small kitchenette for staff, a desk and computer, a printer, files of resident care plans, and increasingly a video monitoring station for resident bedroom and bathroom.

The staff station HVAC specification is: outdoor air at 10 L/s per person continuous (24/7 occupancy); setpoint range 21-23 degrees C (carers typically prefer cooler than residents); NC 35 acoustic; individual return air that does not draw across the medication cabinet or the resident lounge; an entry vestibule between the staff station and the main resident lounge to buffer door cycling at every shift handover. The staff station is at slight positive pressure relative to the corridor to keep odours and pathogens out of the operational nerve centre.

Sleepover carer room (24/7 supervised care)

The sleepover carer room is a dedicated bedroom for the overnight support worker in dwellings with 24-hour supervised care. The carer sleeps on call, ready to respond to resident need. The room hosts a standard single bed, a small wardrobe, an ensuite, and a nurse-call repeater (so the carer is woken by resident calls).

The sleepover carer room HVAC specification is: outdoor air at 10 L/s per person continuous; setpoint range 19-23 degrees C (carer preference; some prefer cool sleeping conditions); NC 25 acoustic to avoid the sleepover carer being disturbed by HVAC noise; modulating-fan indoor unit running at low primary speed; supply diffuser away from the bed with low throw velocity; return high-level near the doorway. The room is at slight positive pressure relative to the corridor and slight positive pressure relative to its ensuite. The ensuite extract is on the same continuous-low-speed background regime as resident bathrooms.

Medical and supply room (PEG feed, oxygen, suction, wound care, continence)

The medical and supply room stores PEG feed pumps and tubing, oxygen concentrator backup bottles, suction units and consumables, wound care dressings and antiseptic, continence pads, catheter and stoma supplies, medication for residents who do not have a separate drug safe at the staff station, and the consumables for resident hygiene and personal care. The room is locked, climate-controlled and inventoried.

The medical and supply room HVAC specification is: outdoor air at 10 L/s per occupant continuous (the room is occupied intermittently for stock-pull but the residents in adjacent bedrooms are continuously affected by leakage); setpoint range 18-22 degrees C with 30-50 percent relative humidity (medication storage benefits from cool dry conditions, and continence pads degrade in high humidity); NC 40 acoustic (the room is not occupied long enough to drive a tight noise budget); separate return that does not draw across the resident bedroom; spark-resistant aluminium terminal on any local exhaust handling oxygen concentrator off-gas. The room is at slight positive pressure relative to the corridor to keep airborne pathogens out, and the door has a positive-latch closer to prevent residents wandering in.

Activity room and Snoezelen sensory room

The activity room hosts group activities for residents — art therapy, music sessions, sensory play, board games, video projection. The Snoezelen multi-sensory room (originally a Dutch concept, now widely used in Australian disability accommodation) is a calming environment with bubble tubes, fibre-optic lighting, projected images, soft surfaces and aroma diffusers, used for sensory regulation in residents with sensory disability, autism or complex behavioural needs.

The activity room specification is: outdoor air at 10 L/s per occupant when occupied (the room is intermittently used so demand-controlled ventilation is acceptable); setpoint 21-24 degrees C; NC 35 acoustic; supply diffuser with low throw and wide pattern.

The Snoezelen room specification is more demanding: supply diffuser face velocity at or below 1.5 m/s with wide laminar throw from perforated face diffusers (high-velocity throw is disregulating for sensory residents); setpoint 20-24 degrees C with 0.5 degree deadband; relative humidity 40-55 percent; NC 25 acoustic (background HVAC noise interferes with the calming function); outdoor air 10 L/s per occupant continuous; controlled lighting coordinated with the HVAC ceiling layout (bubble tubes and fibre-optic effects may require specific ceiling cutouts that interfere with diffuser placement); a small local exhaust at 5-10 L/s ducted to the bathroom riser to manage humidity from bubble tubes, water features and aroma diffusers without producing a noticeable airflow in the calming environment. The duct contractor specifies the supply diffuser as a perforated-face large-area unit on a lined plenum, fabricated in galvanised on the SBAL-V line.

Hydrotherapy pool

An NDIS-funded hydrotherapy pool integrated into an SDA dwelling or a group home is a specialist building service in its own right. The pool hall has chlorine and chloramine load, very high latent humidity, and the residents using the pool are typically wheelchair users with significant physical impairment. The pool hall is at slight negative pressure relative to all adjacent resident spaces, with vapour-tight construction at every wall and ceiling penetration. The pool plantroom houses the filtration system, chlorine dosing, water heating and pool circulation pumps.

The hydrotherapy interface with the broader dwelling HVAC is critical — the pool hall must not vent humidity, chlorine fume or chloramines into the resident dwelling envelope. The duct contractor coordinates with the pool hall HVAC consultant, ensures the pool hall has its own dedicated air-handling unit with dehumidification capability, and treats every dwelling-side wall and ceiling penetration as a vapour barrier. See the SBKJ Indoor Pool and Aquatic Centre HVAC Duct Guide for the full pool hall HVAC scope, which is beyond the typical disability-accommodation duct contractor’s remit and usually outsourced to a specialist sub-contractor.

Therapy room (physio, OT, speech, psychology)

The therapy room hosts visiting allied health professionals — physiotherapists, occupational therapists, speech pathologists and psychologists. The room is configured for one-on-one consultation with a small examination table, exercise equipment, a desk for documentation, and sometimes an adjacent wet area for hand hygiene.

The therapy room HVAC specification is: outdoor air at 10 L/s per occupant; setpoint range 21-23 degrees C; relative humidity 40-55 percent; NC 35 acoustic (low enough to support clear voice intelligibility for speech pathology); supply diffuser with low throw to avoid disturbing exercise equipment; lockable filter access; clean ducted supply with no return across the consulting area. The room is at slight positive pressure relative to the corridor and standard supply-return ventilation.

Laundry block and sluice room

The laundry block in a group home or shared SDA processes continence linen, resident clothing and bed linen continuously. A 6 to 8-resident group home produces 30 to 50 kg of laundry per day, with peak loads of soiled linen from continence management and bed-bathing cycles. The laundry has commercial-grade front-load washers (typically 10-15 kg capacity), commercial-grade dryers (matched capacity), a soaking tank for soiled linen, a folding bench and a linen storage cupboard.

The laundry HVAC specification is: mechanical extract at 12-15 air changes per hour; dryer exhaust on dedicated stainless steel risers with continuous welded longitudinal seams (lint and humidity load), routed through fire-rated shafts to roof discharge with high-velocity fan and no fire damper in the dryer exhaust riser (AS 1668.1 prohibits fire dampers in lint-bearing exhaust). The laundry is at slight negative pressure relative to the corridor to contain humidity and detergent fume. Linen storage cupboard at 10 percent of laundry rate to manage residual humidity.

The sluice room is a separate space adjacent to the laundry, hosting continence pad disposal, sluice toilet (a high-flow flush WC used for emptying bedpans and rinsing soiled linen), bedpan washer and the sluicing detergent storage. The sluice room is a category of its own from a containment perspective and is integrated with the dwelling on every SDA, SIL or group home project.

The sluice room HVAC specification is: most negative space in the dwelling at minus 15 Pa minimum cascade relative to the corridor; fully ducted 304 stainless exhaust riser fabricated on the SBKJ SB-ZF1500 stitchwelder with continuously welded SMACNA Seal Class A longitudinal seams; HEPA bag-in bag-out filter housing at roof discharge to contain bioaerosol release during filter change; continuous extract at 12-15 air changes per hour with no intermittent operation; local exhaust grille over the sluice toilet capturing aerosol at source; no return air back to any dwelling supply (the sluice exhaust is direct to outside through HEPA at roof). The bag-in bag-out filter housing allows the support worker (or contracted hygiene service) to change the HEPA filter without aerosol release. See also the SBKJ Aged Care, Retirement and Disability HVAC Duct Guide for adjacent sluice room context.

Drying room and airing cupboard

The drying room and airing cupboard manage the moisture load from washed linen between the laundry and the linen storage. The drying room handles wet linen that the dryer cannot fully dry (rare in modern dwellings but still relevant for heavy bed linen or pillow protectors), and the airing cupboard buffers freshly dried linen before storage.

The drying room HVAC specification is: mechanical extract at 8-10 air changes per hour; warm supply air at 22-25 degrees C to accelerate moisture removal; humidity sensor with boost activation raising extract to 15 ACH when RH exceeds 70 percent; 304 stainless or aluminium exhaust duct for corrosion resistance under the continuous high humidity. The airing cupboard is on a low-rate continuous extract at 2-5 L/s with a heated rail to keep linen dry.

Wash bay (resident wheelchair wash)

The wash bay is a wet area for cleaning resident wheelchairs and other mobility equipment. It is typically a small tiled enclosure with a floor drain, a wall-mounted shower spray and a wall-mounted detergent dispenser. The wash bay is used several times per week per wheelchair and produces significant water spray, splash and humidity.

The wash bay HVAC specification is: mechanical extract at 10 air changes per hour; 304 stainless exhaust grille and duct (galvanised will corrode quickly under continuous spray exposure); continuous low-speed background extract at 3-5 L/s to manage residual humidity; boost activation on use or on humidity to lift to design rate; weatherproof cowl at roof with low-resistance bird guard. The wash bay is at slight negative pressure relative to the corridor and slight negative pressure relative to the laundry.

Garage and modified vehicle transport bay

The dwelling typically integrates a garage or transport bay for the modified vehicle — a wheelchair-accessible Maxi-Taxi-style van with a side or rear lift, a converted Toyota HiAce or similar, or in some cases a smaller wheelchair-accessible passenger vehicle. The garage is sized for the larger vehicle envelope and the lift deployment area.

The garage HVAC specification is residential-grade with no specific outdoor air rate beyond AS 1668.2 minimum for an unconditioned space; no mechanical ventilation required for typical petrol or hybrid vehicles in a residential garage with natural ventilation through the garage door; carbon monoxide sensor with audible alarm where the garage shares a wall with a resident bedroom (CO load from cold-start engine running); spark-resistant terminal on any local exhaust where LPG storage is present. The garage envelope is sealed against the dwelling living envelope to prevent vehicle exhaust migration during the cold-start period.

Backup generator and battery storage

The HPS dwelling and many shared SDA dwellings host a backup generator and battery storage system sized for the life-critical resident load. The generator is typically diesel or LPG, 8-25 kVA depending on the dwelling load, located in an enclosure adjacent to the dwelling but with a fire-rated separation. The battery storage is a lithium iron phosphate (LFP) or lithium iron phosphate-equivalent system at 10-30 kWh sized for the life-critical equipment (ventilator, suction, oxygen concentrator, profile bed) for at least 8 hours.

The generator enclosure HVAC specification is: radiator extract sized for the generator manufacturer’s heat rejection requirement (typically 10,000-30,000 W of heat reject for the dwelling-scale generator); AS/NZS 60079 Zone 2 classification on LPG bottle storage where present, with spark-resistant terminal on any local exhaust grille; sealed transfer corridor between the generator room and the dwelling fire-rated envelope; positive-pressure ventilation when the generator is running, with louvres sized for the engine combustion air plus the radiator extract. The battery storage room HVAC is residential-grade with thermal management to keep the battery cells within their operating range (typically 15-35 degrees C); some lithium chemistries require active cooling at high state-of-charge or under high power output.

Communications and control room

The communications and control room hosts the carer call system hardware (Vocera, Vital Call, Tunstall or equivalent), the 24/7 monitored alarm receiver for emergency response, the IT rack supporting resident environmental control units, and the smart-home gateway. Some dwellings host a video monitoring station with cameras in the common areas and the high-acuity HPS primary bedroom (with explicit resident consent and family agreement on monitoring scope).

The communications room HVAC specification is treated as a small server room: dedicated DX cooling with redundant capacity sized for the IT rack heat reject (typically 1.5-3 kW depending on the equipment count); clean ducted supply at 18-22 degrees C; separate return that does not pass through resident corridor; provision for UPS heat reject if the UPS is in the same room; monitored temperature alarm that escalates to the on-call carer if the room exceeds setpoint; ozone sensor if a laser printer or older UPS with arc-suppression is in the room (ozone load from UPS arc suppression and laser printer corona discharge is a worker health issue under Safe Work Australia WES 0.1 ppm 8-hour TWA). A communications room failure is a 24/7 monitoring failure — the resident call buttons stop reaching the on-call response service — so this is a life-safety HVAC scope.

Office and administration

The office and administration area handles the operational paperwork of the dwelling — resident care planning, staff rostering, NDIS billing, family communication, incident reporting. The space is typically a small office or open-plan workstation, occupied during business hours by the dwelling manager or the SIL provider’s coordinator.

The office HVAC specification is standard commercial: outdoor air at AS 1668.2 10 L/s per person; setpoint range 21-24 degrees C; NC 35-40 acoustic; standard supply-return ventilation. The space is at neutral pressure relative to the corridor.

Staff amenity and lunch room

The staff amenity and lunch room is a separate space for support workers during break periods, with a small kitchenette (microwave, fridge, kettle), a table for eating, lockers for personal items and access to a staff toilet. The space is separated from the resident-accessed area to provide a respite zone for the workforce.

The staff amenity HVAC specification is: outdoor air at AS 1668.2 10 L/s per person; setpoint range 21-23 degrees C; NC 40 acoustic; standard supply-return ventilation; microwave and kettle exhaust handled by a small wall-mounted rangehood ducted to the bathroom riser (avoids competing for the main kitchen exhaust scope); fridge condenser heat reject sized into the room cooling load.

The Australian standards stack at field-detail depth

This section runs each standard in the working order an HVAC engineer encounters them on an SDA, SIL or group home project. Where the introductory guide describes each standard at concept level, this section focuses on the specific clauses the duct contractor must hit during fabrication and commissioning.

NDIS SDA Design Standard 2019 with the 2024 update

The SDA Design Standard 2019, released by the NDIA in October 2019, with the 2024 update refining specific clauses, is the document that defines what a dwelling must deliver to be enrolled in each of the four SDA design categories. The 2024 update tightened clauses on environmental safety, infection prevention and emergency management — areas where the HVAC delivery contributes directly. For the duct contractor, the binding clauses are the category-specific requirements (ceiling hoist coordination in HPS, ligature-resistant detailing in Robust, sensory-friendly acoustic in IL, reach-range controls in FA), the LHA overlay (Silver, Gold or Platinum), and the documentation expectations for independent design assessor sign-off at concept, mid-construction and pre-handover.

NDIS Quality and Safeguards Commission Practice Standards

The Commission’s practice standards on environmental safety, infection prevention and control, and emergency management drive how the building is used, and therefore how the HVAC must perform. Environmental safety practice means the HVAC system creates no hot surfaces, sharp edges or ligature points within reach of residents. Infection prevention and control practice means filtration, ventilation rate and exhaust performance are documented and maintainable, with the sluice room HEPA and the bathroom continuous-extract evidence pack ready at audit. Emergency management practice means the dwelling remains habitable during predictable failures — power outage, heatwave, smoke event — feeding directly into HPS redundancy and backup-power requirements.

AS 1668.2 mechanical ventilation

AS 1668.2 sets the residential outdoor air rate at 7.5 L/s per person for habitable rooms. For SDA, IL and FA bedrooms are sized at this floor, HPS bedrooms at 10 L/s per person. Bathroom exhaust at 25 L/s on the WC, 30 L/s on the accessible shower. Kitchen exhaust at residential rate with boost for Class 1a, commercial rate for Class 1b/2/9c. Continuous low-speed background extract on bathrooms and the heated towel rail.

AS 4254 ductwork

AS/NZS 4254.1 (flexible duct) and AS/NZS 4254.2 (rigid duct) set sheet metal ductwork construction including gauge, joint construction, sealant class and leakage class. For SDA, the general supply and return is AS/NZS 4254.2 Seal Class C for IL/FA and Seal Class B for HPS where redundancy is on a separate system and infiltration on the secondary circuit must be controlled. Sluice room exhaust and any HEPA-bagged duct is Seal Class A with continuously welded longitudinal seams.

AS 1530.4 fire-rated construction

AS 1530.4 governs the fire-resistance test of building elements. For SDA and SIL dwellings, the construction is typically -/60/60 or -/90/90 depending on the NCC class, with fire-rated wall and floor penetrations meeting the same FRL. Duct penetrations through fire-rated walls require fire dampers rated to the wall’s FRL, or fire-rated wraps to AS 4072.1 and AS 4072.3 on the duct penetration.

AS 1428.1 access and mobility

AS 1428.1 governs the geometry of accessible buildings. For HVAC, the binding clauses are reach ranges (controls between 900 and 1100 mm above floor for seated wheelchair access), clear floor space at fixtures, and surface temperature limits on exposed services. Coordinate ductwork ceiling-void allowance against the 920 mm clear doorway and 1000 mm corridor (1200 mm at LHA Platinum).

AS/NZS 1428.4 and AS 4299 adaptable housing

AS/NZS 1428.4 covers tactile indicators for vision-impaired residents — relevant to ceiling-suspended diffusers where overhead clearance must support cane swing. AS 4299 covers adaptable housing — older than the SDA Design Standard but still binding on back-blocking provisions, floor-loading for hoist anchorage and door-and-corridor adaptability sizing. The HVAC engineer reads AS 4299 alongside AS 1428.1 to understand which wall, ceiling and floor zones are committed to grab-rail and hoist back-blocking and therefore cannot host duct penetrations.

AS 1735 lifts (passenger lift in multi-storey HPS)

AS 1735 governs lift design. HPS dwellings on more than one level (often the case in apartment SDA) require a passenger lift to AS 1735 with cab dimensions sized for a power wheelchair plus an attendant. The lift shaft ventilation, pressurisation under AS 1668.1 and machine room HVAC interface with the dwelling mechanical scope. Ensure machine-room cooling does not draw on resident-zone return air.

AS 1428.5 visual alarm for hearing-impaired

AS 1428.5 covers communications for residents with hearing impairment. Visual alarm beacons in the bedroom, bathroom and common areas must coordinate with the HVAC ceiling layout — avoid placing a diffuser directly under or directly opposite a visual alarm beacon where ceiling shadowing would block the field of view.

AS 5113 facade fire risk (post Grenfell)

AS 5113 governs the fire risk of building facades — relevant for multi-residential Class 2 SDA. Post-Grenfell, the facade combustibility risk is paramount, and the HVAC duct contractor coordinates riser louvre and external grille selection against the facade fire risk assessment to avoid introducing combustible elements at the building envelope.

AS 4072.1 and AS 4072.3 multi-residential fire and smoke barriers

AS 4072 governs penetration sealing through fire- and smoke-rated walls and floors. For Class 2 multi-residential SDA, every duct, conduit, pipe and cable penetration through the apartment-to-apartment fire-rated wall is sealed to AS 4072.1 (FRL) and AS 4072.3 (smoke). The duct contractor specifies fire-rated wraps and sleeves at every fire-rated penetration and coordinates with the fire engineer at concept design.

AS 1851 fire damper maintenance

AS 1851 governs the annual maintenance and drop-testing of fire dampers, smoke dampers and combination fire and smoke dampers. The duct contractor specifies dampers with accessible drop-test mechanism, located so the maintenance contractor can reach them without removing ceiling tiles in resident-accessed rooms. The first-year maintenance schedule is part of the commissioning evidence pack.

AS 1670 fire detection

AS 1670 governs fire detection and alarm systems. For SDA, SIL and group home dwellings where residents may not self-evacuate, smoke detection is in every habitable room (not just the corridor), and the detection coordinates with HVAC shutdown to prevent smoke spread between bedrooms. The duct contractor ensures the supply and return ductwork shutdown sequence is interlocked with the fire detection system, and the system test schedule includes verification of HVAC shutdown.

AS 1668.1 smoke control and stair pressurisation

AS 1668.1 governs fire and smoke control. For Class 2 multi-residential SDA, the stair shaft is pressurised under AS 1668.1 with a roof-mounted supply fan and louvred relief. The duct contractor fabricates the pressurisation duct on the SBAL-V auto duct line with SBSF-1525 round flange terminations.

NCC Class 1a, 1b, 2 and 9c

SDA dwellings are typically NCC Class 1a (single dwelling — most common for HPS individual dwellings), Class 1b (dormitory boarding house up to 12 residents and 300 m² — common for small group homes), Class 2 (multi-residential apartment — common for inner-metropolitan SDA), or Class 9c (residential care with substantial care — uncommon for SDA but applicable to some integrated SDA-SIL-residential care facilities). Each class drives a different fire-safety, smoke-control, accessibility and ventilation scope.

ASHRAE Standard 62.1 ventilation IAQ cross-check

ASHRAE 62.1 is the US ventilation standard. For SDA, where some operators (particularly those with US disability-housing parent operators) reference ASHRAE 62.1 in the internal facility brief, the duct contractor runs a cross-check between AS 1668.2 and ASHRAE 62.1 outdoor air rates. The higher of the two governs.

ASHRAE Standard 170 healthcare

ASHRAE 170 is the US healthcare ventilation standard. For HPS dwellings serving residents with substantial medical equipment (continuous ventilation, suction, oxygen concentrator, IV pumps), some specifiers reference ASHRAE 170 for the air change rate in the primary bedroom and the medical and supply room — typically 6 ACH minimum in the bedroom and 4 ACH minimum in the supply room. SBKJ engineers treat this as a best-practice overlay rather than a regulatory requirement for SDA.

Livable Housing Design Guidelines Silver, Gold and Platinum

The Livable Housing Design Guidelines (formerly Livable Housing Australia) is an industry-led classification system. Silver is the most basic, Gold adds clear-space allowances, Platinum is the most stringent. SDA overlays typically place IL at Silver, FA at Gold or Platinum, Robust at Silver with category-specific reinforcement, and HPS at Platinum because of the bathroom and bedroom envelope sizes required for hoists.

Safe Work Australia WES — workplace exposure standards for residents and staff

Although SDA is housing rather than a workplace from the resident’s perspective, it is a workplace from the support worker’s perspective, and Safe Work Australia’s workplace exposure standards (WES) apply to the air the staff breathe. The relevant WES for SDA, SIL and group home HVAC scope are:

• CO2 5000 ppm 8-hour TWA — applicable to staff station, sleepover carer room and any continuously occupied workspace. The threshold is well above typical residential CO2 levels but is a useful upper-limit cross-check in the HPS primary bedroom where oxygen concentrators raise CO2.
• Methane (CH4) 1.25 percent LEL — applicable to LPG-fuelled kitchens common in regional SDA. Spark-resistant terminal on local LPG bottle storage exhaust.
• Carbon monoxide (CO) 30 ppm 8-hour TWA — applicable to gas appliance kitchens. CO sensor with audible alarm where the kitchen shares a wall with a resident bedroom.
• Refrigerants R32 and R410A — applicable to split-system air conditioning. R32 has a mildly flammable classification (A2L) which drives the indoor unit and piping rules. R410A is non-flammable but a high-GWP refrigerant. Both have WES limits well above any realistic indoor concentration except in catastrophic leak.
• Formaldehyde 1 ppm STEL — applicable to new-build dwellings during the first 6 to 12 months when off-gassing from construction materials is highest. Pre-occupation purge protocols at the AS 1668.2 design rate plus 25 percent are standard.
• VOC general — applicable to all sealants, gaskets, acoustic insulation and duct sealants used in the build. Low-emitting materials specification per the Green Star Indoor Environment credit is best practice.
• Respirable dust 10 mg/m³ — applicable to any ‘mens shed’ workshop space or therapeutic workshop. Local exhaust at the bench plus HEPA discharge.
• Ozone 0.1 ppm 8-hour TWA — applicable to the communications and control room with UPS arc suppression or laser printer corona discharge. Ozone sensor with monitored alarm.
• CO2 elevated in HPS bedroom — applicable to HPS residents using oxygen concentrators, positive pressure ventilators or CPAP. The oxygen concentrator displaces nitrogen, raising room CO2; the ventilator and CPAP humidifier add latent moisture but do not directly add CO2 (CO2 elevation is from the rebreathing pattern combined with continuous occupancy). The 10 L/s per person outdoor air rate manages this.

Australian SDA, SIL and disability-accommodation operators

The Australian SDA market has matured rapidly since the NDIS rollout from 2013. The operator landscape now spans dedicated SDA specialists, mainstream property developers entering the space, integrated providers combining SDA delivery with SIL service, and the legacy disability service organisations who have shifted from group-home operation under earlier funding models to NDIS-funded SDA provision.

Major NDIS SDA providers

Life Without Barriers (LWB) is the largest NDIS provider in Australia with 200-plus SDA properties spanning HPS, Robust, FA and IL categories. LWB’s scale drives a standardised internal HVAC brief that references AS 1668.2 plus 25 percent outdoor air, MERV 13 filtration baseline, anti-ligature grilles in Robust and a documented commissioning evidence pack at every dwelling handover. Aruma (formed by the merger of House with No Steps and Lifestyle Solutions) operates 230-plus SDA properties with a similar internal brief. Achieve Australia, Northcott, The Disability Trust, The Junction Works (Sydney), St Vincent de Paul Society Disability (Vinnies), Anglicare (NSW, VIC and QLD branches), Uniting Care, CatholicCare Australia, Endeavour Foundation (QLD — the largest disability employer in the state), the Australian Federation of Disability Organisations (AFDO), Multicap (multi-state), Cerebral Palsy Alliance (NSW — operates SDA dwellings for the cerebral palsy community), Yooralla (VIC — the largest disability service organisation in Victoria), and ScopeAustralia (formerly Scope Victoria — disability plus aged care) round out the major operators.

Crowdfunded SDA providers include SDA Living (Frasers), Salvation Army Disability Services and Marymead CatholicCare. The crowdfunded model brings additional retail-investor scrutiny on building quality and operating performance, with documentation expectations on HVAC commissioning typically higher than direct-operator-funded dwellings.

SDA specialist developers and builders

Summer Foundation and SDA Australia operate as advocates and research bodies in addition to their direct dwelling delivery. Specialist Disability Accommodation Australia (SDAA) is the peak body for SDA developers. Dignified Living, Hide & Seek SDA and Best of Both Worlds Construction are dedicated SDA specialist builders.

Hayball Architects and ClarkePartner Architects have established SDA expertise across multiple dwelling types. McKenzie Group is a national SDA builder operating 200-plus properties. Property Innovation Group (Sydney) and Bridge Housing (NSW) operate substantial SDA pipelines in the New South Wales market. Hesperia (WA) leads the Western Australian SDA pipeline.

NDIS service providers (broader than SDA)

The broader NDIS service provider landscape — providing SIL, day programs, employment support and other NDIS services without necessarily owning SDA — includes Lifestyle Solutions (now Aruma), Life Without Barriers (LWB), Multicap (national), Skills Plus (employment), BlueCare (Queensland), Anglicare Sydney, Anglicare VIC, Anglicare QLD, Uniting Care, Salvos (Salvation Army), ManakauUnited Care, and Bridge of Hope Foundation. The SIL service overlay on SDA HVAC drives the continuous staff station occupancy, the sleepover carer room scope, and the carer-call control room scope detailed earlier in this guide.

Aged care and disability cross-over operators

Some Class 9c facilities integrate disability accommodation with aged care services, particularly for residents with early-onset dementia who fall into both the NDIS and aged care funding streams. The Australian Aged Care Collaboration (8 aged care peak bodies) coordinates standards across this interface. Estia Health (ASX:EHL), Regis Healthcare (ASX:REG), Japara Healthcare, Bolton Clarke, Calvary and Mater operate facilities with disability components, particularly in regional Australia where pure-SDA scale is hard to achieve.

Industry bodies

The National Disability Insurance Agency (NDIA) is the federal funder, the NDIS Quality and Safeguards Commission is the independent regulator, the Australian Federation of Disability Organisations (AFDO) is the peak advocacy body, National Disability Services (NDS) is the peak industry body for disability service providers, the Disability and Health Network (DHN) coordinates health system interfaces, Inclusion Australia covers LGBTIQ+ disability advocacy, and Children and Young People with Disability Australia (CYDA) covers the under-18 cohort.

SBKJ machine configuration for SDA, SIL and group home fabrication

The SDA, SIL and group home pipeline has a distinct fabrication profile that affects machinery selection for the mechanical contractor or duct fabrication shop. Most projects are small-batch by residential standards — typically 4 to 12 dwellings per project on the Class 1a/1b side, larger Class 2 apartment SDA components running 20-60 dwellings within a larger development — with custom dimensions site-measured against actual ceiling-void clearances after the structural and architectural elements are set.

The SBKJ engineering brief for an SDA-focused fabrication shop is:

• SBAL-V auto duct line in its galvanised configuration as the workhorse for general SDA supply and return. The SBAL-V models SBAL-V-1250J and SBAL-V-1500J run 0.5-1.5 mm thickness at 16 m/min, max width 1250 or 1500 mm, with PLC-controlled batch size and dimension changeover. The PLC accepts a CSV-format batch list — duct length, width, height, gauge, end treatment — and runs through the batch with no operator intervention between pieces. For a 12-dwelling SDA project with 100+ unique duct pieces, the SBAL-V completes the fabrication batch in approximately 14-18 hours of run time, against 40+ hours on a traditional shear-and-bend manual line. The same machine handles aluminium and stainless steel with the appropriate tooling, supporting bathroom exhaust risers in aluminium and Robust terminal sections in 304 stainless. See the SBAL-V product page for the full specification.
• SB-ZF1500 automatic stitchwelder for the stainless plenum, sound attenuator and HEPA-bagged exhaust riser. The SB-ZF1500 handles material thickness 0.8-3 mm, length 100-1500 mm, diameter Φ150-Φ1500 mm, fabricating the lined plenum (Improved Liveability NC 30 acoustic), the impact-rated Robust duct fixings, the sluice room HEPA-bagged 304 stainless exhaust riser with SMACNA Seal Class A continuously welded longitudinal seams, and the redundant HPS secondary circuit stainless terminal section. The SB-ZF1500 is the differentiating machine for SDA work — it is the kit that lets a contractor move from generic residential ductwork into disability-accommodation specialist territory.
• SBSF-1525 round tube flanging for the spiral return riser flange terminations. The SBSF-1525 handles black steel 0.5-2 mm and stainless steel 0.5-2.5 mm, flanging width 75-152 mm, processing diameter 100-2000 mm, max weight 360 kg, requiring 2.5 kW at 380V/50Hz/3PH with dimensions 2200x1100x1240 mm. The machine flanges the round-duct ends on the spiral risers used for multi-storey return paths in Class 2 SDA. See the SBSF-1525 product page for the full specification.
• Spark-resistant terminal selection for medical oxygen concentrator exhaust and LPG kitchen local exhaust. The terminal itself is supplied from the SBKJ accessory range as a finished item rather than fabricated on the duct line.
• SBLR-600 flexible duct forming machine for the flexible duct connector tail at every indoor unit. The SBLR-600 produces flexible duct in diameters Φ80-Φ600 mm, working with non-woven fabric, PVC film and aluminium foil at 0.02-0.06 mm foil thickness, lengths up to 36 m, at a forming speed of 7.6 m/min. See the SBLR-600 product page for the full specification.

For Robust-category work specifically, the anti-ligature grille and vandal-resistant mesh return are accessory items rather than duct line outputs — SBKJ supplies the security-mesh-backed return grille as a finished item from its accessory range, manufactured in 304 stainless steel or heavy-gauge powder-coated steel with welded mesh, shipped as part of the duct package.

For larger Class 2 SDA developments — the apartment-style SDA portfolio within mainstream developer projects — the fabrication profile shifts toward higher-throughput configurations on the SBAL-V galvanised main runs, combined with the SB-ZF1500 small-batch stainless capability for Robust terminal sections, sluice exhaust risers and HPS redundant circuit plenums. This is the configuration SBKJ supplies to several Australian mechanical contractors working with the major SDA developers.

Practical HVAC ductwork specification by category and room — summary

The following condenses the category-specific and room-specific HVAC moves into a compact form suitable for inclusion in a mechanical services tender document.

• HPS bedroom — ducted reverse-cycle primary plus redundant secondary; AS 1668.2 outdoor air at 10 L/s per person continuous; MERV 13 minimum, MERV 14 with non-invasive ventilation; NC 25 with both circuits running; setpoint range 18-26 degrees C; ceiling hoist coordinated duct routing; diffusers at the bedhead wall and opposite wall, not over the bed; high-level return at least 1.5 m from the bedhead; SBAL-V galvanised supply, SB-ZF1500 stainless redundant terminal.
• Robust bedroom — ducted reverse-cycle; AS 1668.2 outdoor air at 7.5 L/s per person; MERV 13 minimum; NC 30; setpoint locked 21-24 degrees C in a locked control cabinet; anti-ligature linear bar grilles or anti-ligature swirl diffusers with tamper-resistant fixings (one-way screws or pin-Torx or square-drive); vandal-resistant return grilles in 304 stainless with welded security mesh; impact-rated diffuser fixings rated for 90 J impact; anti-pick wall penetrations sealed with intumescent mastic and metal escutcheons; concealed duct routing through bulkheads; SBAL-V galvanised supply with SB-ZF1500 stainless terminal sections.
• Improved Liveability bedroom — ducted reverse-cycle; AS 1668.2 outdoor air at 7.5 L/s per person; MERV 13 minimum; NC 25-30; setpoint range 20-26 degrees C with simple soft-touch bedhead controller; sound-attenuator lined plenum at least 600 mm long downstream of the indoor unit; acoustic flex tail at least 1.5 m; main duct velocity at or below 4 m/s, branch at or below 3 m/s, diffuser face at or below 2 m/s; SBAL-V galvanised, SB-ZF1500 stainless plenum where Robust crossover applies.
• Fully Accessible bedroom — ducted reverse-cycle; AS 1668.2 outdoor air at 7.5 L/s per person; MERV 13 minimum; NC 30; setpoint range 20-26 degrees C with thermostat at AS 1428.1 reach range 900-1100 mm; high-level return air; diffusers away from transfer zones; SBAL-V galvanised.
• Resident bathroom (all categories) — 25 L/s on the WC, 30 L/s on the accessible roll-in shower, continuous low-speed background extract at 8-10 L/s, heated towel rail extract continuous; aluminium exhaust riser (IL/FA) or 304 stainless (Robust/HPS); SBAL-V fabricated riser with SBSF-1525 round flange terminations.
• Common kitchen (Class 1b group home) — commercial-grade rangehood with 304 stainless exhaust duct to AS 1668.1, continuous welded longitudinal seams, fire-rated shaft to roof discharge, spark-resistant terminal on LPG bottle storage; SB-ZF1500 stainless riser, SBSF-1525 round flanges.
• Common dining and lounge — AS 1668.2 outdoor air at 10 L/s per person; setpoint 21-25 degrees C; NC 35; supply diffuser with spread throw at low velocity, away from wheelchair circulation; dining at slight positive pressure relative to the kitchen.
• Staff station — outdoor air at 10 L/s per person continuous; setpoint 21-23 degrees C; NC 35; individual return; entry vestibule between staff station and main resident lounge; slight positive pressure relative to the corridor.
• Sleepover carer room — outdoor air at 10 L/s per person continuous; setpoint 19-23 degrees C; NC 25; modulating-fan indoor unit at low primary speed; low-throw diffuser away from bed.
• Medical and supply room — outdoor air at 10 L/s per occupant continuous; setpoint 18-22 degrees C with RH 30-50 percent; separate return; spark-resistant terminal on oxygen concentrator local exhaust; slight positive pressure relative to the corridor.
• Activity room — outdoor air at 10 L/s per occupant on demand; setpoint 21-24 degrees C; NC 35; low-throw wide-pattern diffuser.
• Snoezelen sensory room — supply diffuser face velocity at or below 1.5 m/s with wide laminar throw from perforated face diffuser; setpoint 20-24 degrees C with 0.5 degree deadband; RH 40-55 percent; NC 25; outdoor air at 10 L/s per occupant continuous; small local exhaust at 5-10 L/s for bubble tube and water feature spillage.
• Therapy room — outdoor air at 10 L/s per occupant; setpoint 21-23 degrees C; RH 40-55 percent; NC 35; clean ducted supply; slight positive pressure relative to corridor.
• Laundry block — mechanical extract at 12-15 ACH; 304 stainless dryer exhaust riser with continuous welded seams; slight negative pressure relative to corridor; linen storage cupboard at 10 percent of laundry rate.
• Sluice room — most negative space at minus 15 Pa minimum cascade; fully ducted 304 stainless exhaust riser on SB-ZF1500 with SMACNA Seal Class A continuously welded seams; HEPA bag-in bag-out filter housing at roof; continuous extract at 12-15 ACH; local exhaust grille over the sluice toilet.
• Drying room — mechanical extract at 8-10 ACH with humidity boost to 15 ACH; warm supply at 22-25 degrees C; 304 stainless or aluminium exhaust duct.
• Wash bay (wheelchair wash) — mechanical extract at 10 ACH; 304 stainless exhaust grille and duct; continuous low-speed background; slight negative pressure.
• Garage and transport bay — residential-grade with natural ventilation; CO sensor with audible alarm where shared wall with bedroom; spark-resistant terminal on any LPG storage local exhaust.
• Backup generator enclosure — radiator extract sized for manufacturer’s heat reject; AS/NZS 60079 Zone 2 on LPG storage; sealed transfer corridor to dwelling envelope; positive-pressure ventilation when generator runs.
• Communications and control room — dedicated DX cooling with redundant capacity; clean ducted supply at 18-22 degrees C; separate return; monitored temperature alarm; ozone sensor where UPS arc suppression or laser printer corona.
• Office and admin — standard commercial; AS 1668.2 10 L/s per person; setpoint 21-24 degrees C; NC 35-40.
• Staff amenity and lunch room — AS 1668.2 10 L/s per person; setpoint 21-23 degrees C; NC 40; microwave and kettle exhaust to bathroom riser.

Risks and how to manage them

The four most common HVAC mistakes in SDA, SIL and group home delivery are over-specification (treating every dwelling as if it were HPS, which is unrecoverable in the SDA funding model because payments are tiered by category), under-specification (treating SDA as ordinary residential, which fails independent design assessor review), late coordination with assistive technology (the HVAC engineer arrives after the AT consultant has set cable routes and finds no ceiling space for the supply main), and misclassification of sluice room and HEPA exhaust (the sluice room is the most negative space in the dwelling and any leakage carries bioaerosol — the duct contractor who skips the welded SMACNA Class A seam will fail commissioning).

The fixes are: write the specification against the enrolled SDA category at concept design and re-walk after every architectural change; coordinate with the assistive-technology consultant at BIM clash-detection stage with monthly runs; fabricate the sluice room exhaust riser on the SB-ZF1500 with continuously welded longitudinal seams from day one; document the commissioning evidence pack against the SDA Design Standard 2019 with the 2024 update, the NDIS Practice Standards, AS 1668.2, AS 1428.1, AS 1670 and AS 1851 before pre-handover.

FAQ

How does the High Physical Support category differ from the Fully Accessible category for HVAC?

Fully Accessible delivers a barrier-free wheelchair envelope with reachable controls and clear floor space at every fixture. High Physical Support adds ceiling hoist coordination (the structural hoist track competes with the supply duct for ceiling-void space), wide working setpoint range 18-26 degrees C for residents with impaired thermoregulation, and a redundant reverse-cycle circuit serving at least the primary bedroom because HPS residents cannot self-evacuate. Outdoor air at AS 1668.2 7.5 L/s per person is increased to 10 L/s per person in HPS to manage CO2 load from oxygen concentrators, ventilators and CPAP equipment running 24/7.

What does the Robust SDA category require from the duct contractor?

Vandal-resistant grilles and impact-rated diffuser fixings in 304 stainless or heavy-gauge powder-coated steel with welded security mesh, anti-pick wall penetrations sealed with intumescent mastic and metal escutcheons, tamper-resistant fixings (one-way screws, pin-Torx, square-drive), concealed duct routing through bulkheads, and a locked-cabinet thermostat with narrow setpoint range 21-24 degrees C. SBKJ fabricates the stainless terminal sections on the SB-ZF1500 stitchwelder.

How is the Improved Liveability acoustic target of NC 30 achieved?

The indoor unit located in a service cupboard rather than over the bedroom, a 600 mm sound-attenuator lined plenum downstream of the indoor unit with face velocity capped at 3 m/s, an acoustic flex tail at least 1.5 m long, main duct velocity at or below 4 m/s, branch at or below 3 m/s, diffuser face velocity at or below 2 m/s, and a return grille at least 1.5 m from the bedhead.

Why does the sluice room need negative pressure with HEPA exhaust?

The sluice room handles continence pad disposal, sluice toilet and soiled-linen sluicing with significant bioaerosol and chemical-fume load. SBKJ specifies the most negative space in the dwelling at minus 15 Pa relative to the corridor, a fully ducted 304 stainless exhaust riser fabricated on the SB-ZF1500 stitchwelder with SMACNA Seal Class A continuously welded seams, and a HEPA bag-in bag-out filter housing at roof discharge for safe filter changes.

How should the Snoezelen sensory room be ventilated?

Supply diffuser face velocity at or below 1.5 m/s with wide laminar throw, setpoint 20-24 degrees C with 0.5 degree deadband, RH 40-55 percent, NC 25 acoustic, outdoor air at 10 L/s per occupant continuous, plus a small local exhaust at 5-10 L/s for bubble tubes and water features ducted to the bathroom riser.

What outdoor air rate does AS 1668.2 require for an SDA bedroom?

AS 1668.2 prescribes 7.5 L/s per person for habitable rooms. IL and FA bedrooms are sized at this floor; HPS bedrooms at 10 L/s per person continuous to manage CO2 load from oxygen concentrators, ventilators and CPAP equipment. Bathroom exhaust at 25 L/s on the WC and 30 L/s on the accessible shower.

What duct material specification does SBKJ recommend across the SDA category mix?

SBAL-V galvanised to AS/NZS 4254.2 for general supply and return; aluminium for IL/FA bathroom exhaust risers; 304 stainless for Robust ligature-resistant terminals, the sluice room HEPA-bagged exhaust riser, and HPS redundant circuit plenums, all fabricated on the SB-ZF1500 stitchwelder; SBSF-1525 round flanging for spiral return risers; spark-resistant terminals on oxygen concentrator and LPG kitchen local exhaust; SBLR-600 flexible duct connector at the indoor unit.

How does SIL service delivery differ from SDA for HVAC?

SDA is the building; SIL is the funded support service. SIL drives continuous staff station occupancy, 24/7 sleepover carer rooms, a communications and emergency-response control room hosting nurse-call hardware (Vocera, Vital Call, Tunstall), and door-cycling at every shift handover. SBKJ specifies the staff station as a separately conditioned zone with an entry vestibule to the resident lounge, and the communications room as a small server room with dedicated DX cooling.

What SBKJ machine configuration does an SDA-focused fabrication shop need?

SBAL-V auto duct line in galvanised configuration as the workhorse for general supply and return; SB-ZF1500 automatic stitchwelder for the stainless plenum, sound attenuator and HEPA-bagged sluice exhaust riser; SBSF-1525 round tube flanging for spiral return risers; SBLR-600 flexible duct forming machine for the flex tail at the indoor unit; spark-resistant terminal accessory items for medical oxygen and LPG kitchen local exhaust. See the SBKJ machines page for the full catalogue.

How does the dwelling stay habitable during a power outage in an HPS dwelling?

The dwelling integrates a battery storage system sized for the life-critical resident load (excluding the air conditioning) for at least 8 hours, plus a backup diesel or LPG generator sized for the full load including the primary HVAC. The HVAC engineer coordinates transfer switch operation, generator radiator extract, the AS/NZS 60079 Zone 2 LPG storage classification, and the brief electrical interruption during transfer that may briefly trip the indoor unit. The redundant HPS secondary circuit on a separate electrical circuit provides resilience against a single-circuit failure.