Why personal services HVAC is its own discipline
Most fit-out builders treat a hair salon as a generic retail tenancy. From the structural envelope outward, that is approximately correct — the same shopping-strip premises, the same heritage bulkhead depths, the same after-hours access constraints. But once the brief crosses into mechanical services, salon, spa and nail-bar fit-outs become a distinct engineering problem. The contaminant load is chemical rather than thermal, the acoustic target in a treatment room is closer to a recording studio than a shop floor, and the regulatory frame stitches together state public health legislation, AS 1668.2 ventilation engineering, AS 4674 personal services premises construction, Safe Work Australia workplace exposure limits, Therapeutic Goods Order clinical controls where injectables are dispensed, and the ACCC Cosmetics Information Standard 2020 wherever take-home product is sold from the salon's retail shelf.
The contaminants matter because they are not abstract. Ammonia from hair colour development approaches the 25 ppm Safe Work Australia 8-hour TWA inside the bowl plume on a busy Saturday. Acetone vapour at a nail-tech bench routinely peaks in the hundreds of parts per million during artificial-nail removal — Safe Work Australia caps the STEL at 750 ppm. Methyl methacrylate at 50 ppm 8-hour TWA is the binding constraint for acrylic systems; toluene at 50 ppm 8-hour TWA for traditional nail glues; perm thioglycolate is a documented skin sensitiser; keratin smoothing treatments emit formaldehyde at variable rates. None of this disappears under bulk dilution alone — the airflows needed to dilute a six-station nail salon to compliance through outside air alone are uneconomic. The correct answer is local source extract at the bench supplemented by code-compliant general ventilation.
This guide is written for fit-out builders, mechanical contractors and franchise development teams designing salon, spa, barber, nail and laser-clinic premises across Australia. It is a single reference covering the ventilation code, the chemical exposure limits, the room-by-room design parameters from blow-dry bench to hammam, and the tier-by-tier landscape of Australian operators so an engineer can size for the brand they are building for.
1. The Australian regulatory frame
Five overlapping instruments govern HVAC and ductwork engineering for personal services premises in Australia. Each addresses a different concern, and the design must satisfy all of them simultaneously. Sizing for AS 1668.2 alone misses the AS 4674 surface finish requirements; satisfying AS 4674 surface finishes misses the workplace exposure limits; pricing the workplace exposure limit controls misses the Therapeutic Goods Order overlay where injectables are dispensed. The five instruments must be read as a coherent set.
AS 1668.2 — the mechanical ventilation rate
AS 1668.2 is the Australian Standard for the use of mechanical ventilation and air-conditioning in buildings. It specifies the minimum outside-air rate required for occupant comfort and contaminant dilution across a wide range of occupancy classifications. For hair and beauty salons it applies a two-part formula: V_p = 10 L/s/person of outside air against realistic peak occupancy, plus V_a = 0.3 L/s/m² of floor area against the gross tenancy floor. The two are summed, with an occupancy diversity factor applied where the standard permits — realistic concurrent load is typically 70% to 85% of the theoretical maximum.
For a 120 m² hair salon with 20 chairs, modelled at 14 concurrent occupants (10 clients, 4 staff) at lunchtime peak, the calculation runs as follows. The population component is 14 × 10 L/s = 140 L/s. The area component is 120 × 0.3 = 36 L/s. The sum is 176 L/s of outside air before any local exhaust. In practice a 200 L/s AHU is selected for design margin. The same 120 m² premises configured as a 6-station nail salon generates the same 176 L/s code minimum — but the nail-salon configuration also requires roughly 1,200 L/s of local source extract on top, drawn from six 200 L/s extract arms. This is the central design distinction between a hair tenancy and a nail tenancy at identical floor area, and it is the most common engineering oversight on small-business salon fit-outs.
AS 1668.2 explicitly requires local exhaust at sources of contaminant. Source extract is a separate engineering deliverable on top of the general outside-air rate, not a substitute. A fit-out engineer who designs only the general rate and omits source extract is non-compliant against the standard and the WHS legislation.
AS 4674 — construction and fit-out of food premises and personal services premises
AS 4674 prescribes construction standards for food premises and personal services premises. The personal services section captures hair, beauty, nail, tattoo, body-piercing and skin-penetration premises explicitly. The standard specifies floor, wall and ceiling finishes that are smooth, impervious, non-absorbent and easily cleaned, hand-wash basins at minimum spacing, sealed joints between fixtures and surrounding finishes, and storage that protects clean and dirty linen from cross-contamination. The HVAC design intersects AS 4674 at three points. First, supply diffusers and return grilles must be installed in finishes that satisfy the cleanability requirement — drop-out diffusers with deep coffers that collect dust are non-compliant here. Second, ductwork penetrations through walls and ceilings must be sealed to maintain surface integrity. Third, where the premises is licensed for skin penetration, the ventilation strategy must avoid recirculation of treatment-room return air through general supply paths.
State and territory public health legislation incorporates AS 4674 by reference and adds local licensing and inspection regimes on top — the Victorian Public Health and Wellbeing Act 2008, NSW Public Health Act 2010 skin-penetration code, Queensland Public Health (Infection Control for Personal Appearance Services) Act 2003, and analogous regimes in SA and WA. An environmental health officer will inspect on commissioning and scrutinise ventilation, surface finish and hand-wash basin placement together.
Safe Work Australia exposure limits
Safe Work Australia publishes the Workplace Exposure Standards for Airborne Contaminants, which sets the legally binding upper limits for employee exposure under the Work Health and Safety legislation in every Australian state and territory. The standards relevant to salon, spa and nail tenancies are listed below. These are the values the HVAC engineer must design to, and they are the values an inspector will verify if a complaint is investigated.
- Ammonia. 25 ppm 8-hour time-weighted average. Ammonia is the active developer in oxidative hair colour, particularly in high-lift and lightening formulations. Concentration in the bowl plume on a busy day with three colour services in progress is documented at low double-digit ppm at the breathing zone of the senior stylist. Local exhaust at the colour bar reduces this to single digits.
- Acetone. 750 ppm 15-minute short-term exposure limit, 500 ppm 8-hour TWA. Acetone is the solvent in nail-polish remover and the primary vapour during artificial-nail removal at the nail-tech bench. Peak exposures of several hundred ppm at the tech's breathing zone are documented on busy benches without source extract. With a source-extract arm at 0.3 m/s capture velocity, breathing-zone exposure drops to tens of ppm.
- Methyl methacrylate (MMA). 50 ppm 8-hour TWA. MMA is the monomer in some acrylic-nail systems. Although MMA is largely displaced by ethyl methacrylate (EMA) in modern Australian salons, MMA persists in some discount product lines and the exposure limit is the legally binding constraint when it is in use.
- Ethyl methacrylate (EMA). The Safe Work Australia framework treats EMA under the methacrylate family with similar engineering controls. EMA has lower vapour pressure than MMA and is more amenable to source-extract control at typical bench airflows.
- Toluene. 50 ppm 8-hour TWA, 150 ppm STEL. Toluene is the solvent in traditional nail glues and adhesives used for nail tips and wraps. Modern formulations have moved away from toluene where possible, but it is still present in some product lines.
- Formaldehyde. 0.3 ppm STEL, 1 ppm peak. Formaldehyde is released from some keratin smoothing and "Brazilian blowout" treatments during heated styling. Formaldehyde-releasing treatments are the binding constraint that drives source extract above the styling chair where they are performed, even in a tenancy that does not have a dedicated colour bar.
- Thioglycolate (ammonium thioglycolate, glycerol thioglycolate). Permanent-wave and chemical relaxer active. Skin sensitiser with no inhalation TWA, but a recognised dermal hazard requiring local extraction at the perm-wave station and PPE protocols on the WHS side.
- Hydrogen peroxide. 1 ppm 8-hour TWA. Oxidative developer in hair colour. Present at low concentrations in the bowl mix; engineering controls overlap with the ammonia source extract.
The Safe Work Australia limits are not aspirational — they are the legally binding employee-exposure ceiling, and a breach is an offence under the WHS Act enforced by state regulators (WorkSafe Victoria, SafeWork NSW, WHSQ, SafeWork SA, WorkSafe WA). The HVAC engineering controls are the primary engineering means of compliance, supplemented by PPE and administrative controls on the operator side.
ACCC Cosmetics Information Standard 2020
The ACCC Cosmetics Information Standard 2020 is the consumer-protection instrument that governs the labelling of cosmetic products sold to Australian consumers. It does not regulate HVAC directly. It becomes relevant to the salon HVAC engineer in one specific way: many modern salons operate a retail shelf alongside the treatment chairs, selling take-home professional product. The retail shelf is a distinct merchandising zone from the production floor, with different lighting, different cleaning protocols and different ventilation pressure relationships. The fit-out engineer should design the retail shelf as a positive-pressure clean zone relative to the wash basin and colour bar areas, to prevent migration of humidity and chemical contaminants into the retail product.
Therapeutic Goods Order
Where a salon, beauty clinic or day spa dispenses Schedule 4 substances — botulinum toxin (Botox, Dysport, Xeomin), dermal fillers, prescription cosmetic actives — the premises is captured under the Therapeutic Goods Order framework. It must operate under a credentialed medical or nursing practitioner, substances must be stored in a temperature-controlled environment with continuous monitoring, and the treatment room is uplifted to a clinical-grade HVAC standard with HEPA filtration on the supply, dedicated extract not shared with retail air, and a documented air-change rate of 6 to 10 ACH. This is the threshold that separates a beauty salon HVAC scope from a cosmetic clinic HVAC scope. Laser hair removal and IPL rooms do not cross the Therapeutic Goods Order threshold — they require ambient HVAC plus AS 1668.2 outside air, with eye protection and signage handled through separate WHS controls.
2. Hair salon HVAC engineering
A typical Australian hair salon between 80 m² and 250 m² with 8 to 24 chairs is a thermally and chemically active environment with a distinct daily cycle. Saturday morning sees the highest density of colour services, with two to four colour bowls in active development and a corresponding spike in ammonia and peroxide concentration. Weekday afternoons see lighter occupancy but longer service times. The HVAC system must handle both load profiles without overshooting the dehumidification in winter or undercooling in summer.
Colour bar source extract
The single most impactful engineering decision in a hair-salon fit-out is whether to design a dedicated colour bar with source extract or to rely on general dilution. The dedicated colour bar approach concentrates the contaminant-emitting activity in one room or bay, allowing the extract air to be ducted to a single rate-controlled fan and the makeup air to be tempered. Three engineering options are commonly used. The first is a wall-mounted slot extract above the colour bar bench, running the full bench length, at a face velocity of 0.5 m/s drawing approximately 100 L/s per linear metre of bench. The second is an articulated arm hood above each bowl, identical in principle to a laboratory fume-extract arm, drawing 150–200 L/s per arm. The third is a ventilated colour-mixing cabinet, fully enclosed with a sash, drawing 150 L/s per cabinet — this is the highest-capture-efficiency option and is increasingly seen in premium and franchise salons. SBKJ slim-profile galvanised branch ductwork in 250 mm or 300 mm rectangular section threads the extract collection through the typical 300 mm Australian shopping-strip bulkhead depth.
Wash basin and backwash row
Backwash chairs are localised humidity sources during the wash and condition steps. A standard four-chair backwash row generates approximately 0.3 to 0.5 kg/hr of evaporative load during active use. Dedicated exhaust above the row, ducted to a small 80 L/s EAF, prevents humidity migration into the styling floor and protects ceiling, lighting and joinery finishes. Where the salon is in a heritage premises with limited ceiling void, a slot-extract grille along the backwash wall is more common than a coffered ceiling exhaust. The branch ductwork is galvanised but should be insulated externally where it runs over an air-conditioned space, to prevent condensate forming on the cold surface during humid conditions.
Hair drying station air movement
Overhead hood dryers, blow-dry stations and stand-mounted styling dryers are intermittent point sources of heat. Each operating dryer adds approximately 1.0 to 1.8 kW of sensible heat to the room during the styling period. The HVAC design accommodates this through high-volume low-velocity supply diffusers above the styling row, with the supply face velocity tuned to deliver comfort without disturbing the styling itself. Radial swirl diffusers directly over the chair are avoided — they push humid plumes back into the client's face. The preferred geometry is a linear slot diffuser with the throw directed parallel to the mirror wall, allowing the supply air to mix with the dryer plume above head height before falling into the comfort zone.
Retail shelf zone
Salon retail shelves are typically located near the front of the tenancy, separated from the colour and styling floor by the reception desk. The HVAC design treats the retail zone as a positive-pressure clean zone relative to the chemical-emitting bays, achieved by sizing the supply to deliver slightly more air than the return removes in the retail zone, with the balance returning through transfer paths from the production floor. This is the same pressure-relationship principle used in retail pharmacy and food retail, and it preserves the product packaging from humidity migration and chemical odour absorption.
Reception, waiting and consultation
The reception and waiting area is the public-facing zone of the salon and the first impression. Acoustic target is typically NC-35, slightly quieter than general retail floor, to support consultation conversations and to filter out plant noise from the back-of-house mechanical room. Lighting is warm-tone and high CRI for cosmetic colour accuracy at the consultation desk. The HVAC design uses architectural linear diffusers integrated into the joinery or ceiling plane, with concealed return grilles routed through the reception desk plinth or rear wall.
3. Beauty salon and treatment room HVAC engineering
A beauty salon differs from a hair salon in that the activity is centred on individual treatment rooms rather than open-floor chairs. Each treatment room is a separately conditioned space with its own acoustic, lighting and ventilation requirements, connected to the main AHU through branch ductwork with terminal control at the room. The design parameters below are the typical Australian fit-out benchmarks for premium and franchise operators.
Treatment room design parameters
Temperature 22 to 24 °C dry-bulb, 50% relative humidity, NC-30 acoustic target. The NC-30 target is the binding parameter — it drives diffuser selection, plant location, ductwork lining and break-out attenuation throughout the supply path. Lighting is dimmable warm-tone with separate switching for the working light and the ambient relaxation light. Air supply is delivered through low-velocity displacement diffusers near floor level or through ceiling-mounted laminar diffusers with very low face velocity, to prevent draught across the treatment bed. Return is on the ceiling, routed through a lined plenum to attenuate any cross-talk between adjacent rooms.
Treatment room ventilation rates
A typical 12 m² treatment room with one therapist and one client is dimensioned at AS 1668.2 base rates — 2 occupants times 10 L/s plus 12 m² times 0.3 L/s/m² = 24 L/s. This is the floor of the design; many premium operators specify 30 to 40 L/s per room to support the comfort target and to provide a margin for treatments using essential oils, hot stones or steamy facial protocols. Where the treatment involves micro-needling, dermaplaning or any skin-penetration procedure under AS 4674, the room must operate at slightly negative pressure relative to the corridor, with the extract dominated and the supply trimmed, to prevent contamination migration into adjacent clean zones.
Hot stone, hammam and steam room
Hot stone treatment rooms run at the upper end of the comfort range, typically 24 to 26 °C, with the stones themselves contributing radiant heat. Hammam and steam rooms are a distinct mechanical scope — saturated air at 40 to 45 °C and 100% RH inside the steam cabin, surrounded by an anteroom at 40% RH and 22 °C, with a dedicated AHU and active dehumidification on the return. Ductwork through the steam zone is 316 stainless with welded longitudinal seams and stainless support brackets. Condensate management is critical — every horizontal duct run pitches to a drain, and the corrosion-resistant grille materials are specified to prevent rust streaks in the architectural finish.
Sauna anteroom
Traditional Finnish sauna cabins operate at 80 to 90 °C and 10 to 15% RH inside the cabin, with the anteroom at 40% RH and 22 °C as the transition zone. The anteroom HVAC is independent of the cabin's own air supply (which is typically a passive intake and exhaust), and its role is to maintain a comfortable transition and to extract the moisture released when guests exit the cabin. A 30 L/s dedicated exhaust above the cabin door is standard practice in Australian premium-spa fit-outs.
Spa pool and hydrotherapy
Spa pool and hydrotherapy zones share the chloramine ventilation challenge with indoor aquatic facilities. Chloramines form when chlorine reacts with organic matter from bathers, releasing trichloramine vapour that is the primary contributor to "swimming-pool smell" and to respiratory irritation. The ventilation strategy is dedicated negative-pressure exhaust above the pool surface, with makeup air introduced from the perimeter rather than directly over the pool. Outside-air rate is uplifted relative to AS 1668.2 base rates because chloramine is a contaminant not captured in the general formula. Ductwork in the immediate wet zone is 316 stainless or HDPE; the surrounding plant-room ductwork is galvanised with an external coating to resist the chloramine-laden return air.
Massage room
Dedicated massage rooms are designed to the same temperature, humidity and acoustic targets as the general treatment room — 22 to 24 °C, 50% RH, NC-30 — with even tighter attention to draught control. The therapist works in close physical proximity to the client for an extended period; any supply diffuser cold-draught onto the client's exposed skin will be perceived immediately. Low-velocity displacement supply near floor level is the preferred geometry, with the return on the ceiling routed through a lined plenum. Door undercut is the standard return-air transfer path; doorway grilles compromise acoustic privacy and are avoided.
4. Nail salon HVAC engineering
Nail salons are the most chemically aggressive of the personal services premises by some margin. Acetone, ethyl methacrylate, methyl methacrylate, toluene, ethyl acetate, butyl acetate and a long list of secondary solvents are present at the bench during normal operation. A six-station nail salon operating at typical Saturday-morning load generates a contaminant emission rate that cannot be diluted to compliance through outside air alone at any reasonable HVAC sizing. Source extract at each station is the engineering control of choice, and it is non-negotiable on any fit-out that intends to satisfy the Safe Work Australia exposure limits.
Source-extract arm at each station
The standard nail-station source-extract installation is an articulated arm above each bench, with the hood capture at 200 to 300 mm above the bench top, drawing 200 to 300 L/s. Brand-name arms (Plymovent, Lincoln Electric, Nederman, Movex) are designed for welding-fume capture and translate directly to nail-bench application with no modification. The capture velocity at the bench surface is 0.3 m/s minimum, which corresponds to a face velocity at the hood opening of 0.5 m/s through a 300 mm diameter cone. The arm articulates to allow the technician to position the hood directly over the work area, and a low-noise EC fan motor in the riser keeps bench-level noise below NC-40.
Downdraft slot as alternative
Where the salon layout favours fixed benches in a row — particularly the long single-side configuration common in shopping-centre kiosks — a downdraft slot built into the back edge of the bench is a clean alternative to the articulated arm. The slot runs the full bench length at a face velocity of 0.5 m/s, drawing the contaminant plume horizontally across the bench and into the riser. The downdraft approach is acoustically quieter than the arm but slightly less effective at capturing the high-altitude plume that rises during heated nail-curing operations.
Branch ductwork material
For general nail-salon use, galvanised steel branch ductwork is the standard specification. Galvanised is durable, smooth-bore, accepts standard fittings, and resists the typical solvent exposure at the airborne concentrations seen downstream of the capture hood. For high-volume nail-bar use, particularly salons that perform a large number of acrylic-nail enhancement services with sustained MMA or EMA exposure, 316 stainless branch ductwork is justified — the lifetime corrosion resistance offsets the higher install cost, and the smooth-bore stainless surface is easier to clean during the periodic deep-clean cycle. SBKJ rectangular ductwork plant fabricates both galvanised and stainless from the same machine envelope by changing the coil — the slim-profile rectangular line was designed precisely for the kind of mixed-material branch runs that personal services fit-outs require.
Main exhaust riser
Six bench branches feeding into a single main extract riser at 1,500 L/s is a typical sizing for a small to mid-size nail salon. The riser routes vertically through the shopping-strip building envelope, terminating at roof level with a weather hood and an architectural louvre that discharges away from any neighbouring residential air intakes. Where the building configuration prevents a direct roof discharge — common in heritage premises with stratum titles above the salon — the exhaust is routed horizontally to the rear lane through a side-mounted louvre, with an activated-carbon filter bank in the run to mitigate odour migration to adjacent premises.
General room ventilation
The general room ventilation in a nail salon is sized to AS 1668.2 base rates — V_p plus V_a — and is provided through standard architectural diffusers in the ceiling. The general supply is positive relative to the bench-extract negative draw, so makeup air flows naturally from the supply diffusers across the room to each bench. The pressure relationship matters: a negative-pressure room with negative-pressure benches will draw outside air uncontrollably through every door undercut and shopfront seal, which compromises both comfort and energy performance.
Pedicure station
Pedicure stations include a foot-soak basin and add a humidity source to the room. The chemical emission at the pedicure bench is lower than at the manicure bench (less acetone, less acrylic), but the humidity and the cleaning protocols around the basin drive a small dedicated exhaust above the chair, typically 50 L/s, ducted to the same exhaust riser as the manicure benches. Surface finishes around the basin are AS 4674 compliant — sealed, impervious, easily cleaned.
5. Barber shop HVAC engineering
Barber shops are simpler than full-service hair salons. The activity is concentrated on dry cuts and beard work, with minimal chemical services. The contaminant load is loose hair, talc and styling-product aerosols, and the engineering focus shifts from chemical exposure to comfort, acoustics and shop atmosphere. The Australian premium barber market has grown substantially over the last decade, with brands like Eddy's Cutz, The Mens Lounge and Razor operating multi-site networks at design fit-out budgets that approach or exceed equivalent women's salons.
General ventilation
AS 1668.2 base rates apply — V_p = 10 L/s/person and V_a = 0.3 L/s/m². A 100 m² barber shop with 6 chairs and a typical 10-person peak load (6 clients, 3 barbers, 1 reception) is dimensioned at 100 L/s plus 30 L/s, or 130 L/s of outside air. In practice a 150 L/s AHU is selected. The general supply geometry is similar to a women's salon — linear slot diffusers parallel to the mirror wall, ceiling return.
Loose-hair extract
Loose hair settles on every horizontal surface in a barber shop and accumulates in the corners of the room. The return-air grille is the natural collection point, and a coarse pre-filter on the return prevents hair from entering the AHU coil. Filter replacement is typically weekly in a busy six-chair barber shop, and the filter housing is designed for tool-free access. Some premium fit-outs add a dedicated floor-level extract at each chair, drawing loose hair down at the chair base rather than allowing it to rise into the breathing zone — this is a comfort feature rather than a code requirement.
Beard wash and steam towel
The premium barber-shop service stack includes a beard wash and hot-towel finish, which generates localised humidity at the wash sink. A small dedicated exhaust above the sink, typically 40 L/s, prevents humidity migration into the styling floor.
Acoustic and atmosphere
Premium barber shops invest heavily in atmosphere — exposed brick, dark joinery, bourbon-bar lighting, vinyl music systems. The acoustic design respects the curated soundscape: NC-35 background, with the AHU and return-air paths attenuated to prevent intrusion. Plant location is critical — a rooftop AHU connected through a short supply run is preferable to a ceiling-void air-handler that broadcasts compressor noise into the shop.
6. Day spa HVAC engineering
Day spas are the most complex of the personal services premises. A flagship day spa combines treatment rooms, hammam, sauna, steam, hydrotherapy, retail shelf, café and consultation across 400 to 1,000 m² of floor area, with each zone operating at a different temperature, humidity, acoustic and pressure relationship. The HVAC engineering is multi-zone air handling with dedicated mini-AHUs for the wet and chemical zones, integrated with a BMS that manages zone setpoints throughout the day. The leading Australian day spa networks — Endota Spa, Aurora Spa, Cinq Spa, Spa Anise and the hotel-spa programmes of premium accommodation brands — operate at this scale.
Wet zone separation
The hammam, sauna, steam and hydrotherapy zones are mechanically separated from the dry treatment rooms and the retail floor through pressure relationships and physical envelope. The wet zones run at slightly negative pressure relative to the corridors, drawing makeup air through the doorways rather than pushing humid air out. The dry treatment rooms run at slightly positive pressure relative to the corridor, protecting the treatment-bed environment from corridor air. The retail floor at the front of the spa runs at clear positive pressure relative to the back-of-house, preserving the merchandising environment from any spa-zone humidity migration.
Corridor and waiting area
The corridor between treatment rooms is acoustically critical — door slams, footsteps and conversations between staff are perceived through the treatment-room door. Acoustic ceiling tile, carpet on the floor, and lined plenum returns through the corridor ceiling are standard. The waiting and relaxation lounge is designed to the same NC-30 target as the treatment rooms, with a low-velocity displacement supply and concealed returns.
Tea kitchen and refreshment bar
A flagship day spa typically includes a tea kitchen and refreshment bar for post-treatment service. The kitchen scope is light — kettle, espresso machine, refrigerated bar — and the HVAC scope is correspondingly modest, with a small extract above the espresso machine and a fridge plant-room exhaust. Where a full food service is offered (light lunch, breakfast), the kitchen HVAC scope steps up to the café and quick-service restaurant standards covered separately in our café guide.
Retail and product display
The retail shelf at the front of a day spa is the highest-margin revenue line in many operations, and the HVAC design protects the product investment. Positive pressure relative to the back-of-house, stable temperature and humidity, low-velocity supply that avoids dust accumulation on the product surfaces, and lighting integration that does not create radiant heat onto the product packaging.
7. Cosmetic injection clinic HVAC engineering
Cosmetic injection clinics dispensing Schedule 4 substances cross the regulatory threshold from beauty salon into clinical premises. The HVAC scope correspondingly uplifts. The treatment rooms are designed to clinical-grade ventilation standards, the substance storage rooms operate under continuous temperature and humidity monitoring, and the broader pressure relationships across the tenancy reflect the clinical-versus-retail zonation. The leading Australian operators in this space — Laser Clinics Australia, Australian Skin Clinics, Clear Skincare Clinics, Silk Laser Clinics, Profile and Brazilian Beauty — operate at this clinical-uplift specification across their flagship sites.
Treatment room clinical uplift
Cosmetic injection treatment rooms are designed at 6 to 10 air changes per hour, with HEPA filtration on the supply air at minimum H13 efficiency, dedicated extract not shared with adjacent retail return paths, and slight positive pressure relative to the corridor to maintain a clean envelope. Temperature is 22 to 24 °C dry-bulb, 40 to 50% RH, NC-30 acoustic. The room is finished to AS 4674 clinical standards — smooth, impervious, easily cleaned, with coved skirtings and sealed penetrations through every surface.
Substance storage
Botulinum toxin and dermal filler products are stored at 2 to 8 °C under the Therapeutic Goods Order temperature requirements, with continuous monitoring through a connected logger that records to a centralised quality management system. The storage refrigerator is plumbed into the clinic HVAC plant only insofar as the refrigerator condenser heat is rejected into the back-of-house return path; the storage compartment itself operates on its own refrigeration loop. The room housing the storage refrigerator is conditioned to a stable ambient — 22 °C, 50% RH — to ensure the refrigerator operates within its design envelope.
Laser hair removal and IPL
Laser hair removal and IPL rooms do not require clinical-grade HVAC. The treatment is non-invasive, the substances on the trolley are limited to cooling gels and ambient consumables, and the room operates on ambient HVAC plus AS 1668.2 outside-air rates. Eye protection is the primary WHS control, supported by signage on the door and an interlock on the door access where the laser is in use. Acoustic target is NC-35 — quieter than retail but not as quiet as a treatment room.
Cross-pollination with the broader tenancy
The challenge in a clinic-plus-salon tenancy is the pressure relationship between the clinical zone and the retail zone. The clinical treatment rooms must be slightly positive relative to the corridor; the substance storage must be temperature-stable regardless of what is happening in the retail floor; and the retail floor must remain positive relative to any salon zones with chemical emission. A four-zone BMS managing supply and exhaust at each zone is the standard solution, with damper actuators on each branch and a commissioning regime that verifies pressure relationships under each operating mode.
8. Tattoo studio HVAC engineering (where co-located)
Tattoo studios are regulated state by state under skin-penetration codes incorporated into AS 4674. They are increasingly co-located with barber shops and edgy hair-and-beauty tenancies that target a younger demographic. The HVAC scope is uplifted relative to a standard barber shop in two areas. First, ink-aerosol exhaust above the tattoo station — a directional extract hood at the artist's working position, drawing 150 to 200 L/s, prevents the ink-needle aerosol from rising into the artist's breathing zone. Second, the room operates at slight negative pressure relative to the rest of the tenancy, preventing ink-aerosol migration into adjacent zones. Surface finishes are AS 4674 compliant, with reinforced cleaning protocols on the WHS side.
Body piercing and other skin-penetration premises follow the same HVAC scope as the tattoo studio. The activity is more concentrated in time (a piercing service lasts minutes; a tattoo can be hours), but the engineering controls — local extract, negative pressure to corridor, AS 4674 surfaces — are identical.
9. Acoustic engineering for personal services
Acoustic targets vary substantially across the zones of a personal services tenancy, and the HVAC system is one of the most significant noise sources to control. The table below summarises the standard Australian acoustic targets.
- Treatment room (massage, facial, body): NC-30. Quiet enough to support relaxation; tight enough that any HVAC noise is perceptible and must be designed out.
- Cosmetic injection treatment room: NC-30. Clinical context plus client comfort.
- Laser hair removal / IPL room: NC-35. Quieter than retail; not as quiet as a treatment room.
- Retail floor: NC-35. Background music plays here, and the HVAC must not compete with the music or the reception conversation.
- Reception and consultation: NC-35. Conversational acoustic.
- Barber shop floor: NC-35. Background music plays here too, but typically louder than salon retail; HVAC noise floor is less constrained.
- Nail salon floor: NC-40. The acoustic environment is dominated by source-extract fan noise and bench conversation; the HVAC contribution is one of many sources.
- Hammam, steam, sauna: NC-30. Quiet enough to preserve the relaxation experience.
- Hydrotherapy and spa pool: NC-40. The water itself generates noise; HVAC is not the dominant source.
Achieving NC-30 in a treatment room requires the entire supply path to be acoustically designed. Lined ductwork in the run upstream of the room, a lined plenum return, low-velocity diffusers selected for NC-25 at the design airflow, and an AHU located outside the treatment-room acoustic envelope. Where the AHU must be located within the tenancy, an acoustically lined plant cupboard with attenuators on both the supply and return is the standard solution.
10. The Australian operator landscape
Fit-out engineering decisions are downstream of the brand the tenancy is being built for. A franchise operator with a national brand guideline has a different specification ceiling than an independent owner-operator. The summary below covers the leading Australian personal services brands by tier.
Hair salon operators
- Just Cuts. Australia's largest hair salon franchise network, 200-plus franchised salons. Value-focused fit-out — efficient layouts, durable finishes, modest mechanical scope. Source extract at colour bowls is increasingly added at refurbishment.
- Hairhouse Warehouse. Retail-plus-salon model under Quadrant Private Equity ownership. Retail floor dominates; salon component is a small treatment area at the back. Retail-standard HVAC with a small salon overlay.
- BLOWBAR. Premium blow-dry concept with sites in Sydney and Melbourne. Fast styling rather than colour, so source-extract is less critical; comfort target is premium.
- Fox & Jane. Premium Sydney and Melbourne salon brand. Mid-size tenancies, premium finishes, full colour scope. Source extract at colour bowls is brand-specified.
- Rokk Ebony. Premium Sydney salon brand with multiple sites. Full colour service, premium acoustic, integrated retail shelf.
- Edwards & Co. Premium Sydney salon brand with strong editorial profile. Mechanical services integrated into the architectural plane.
- The Beauty Spot. Multi-site beauty brand operating salon-plus-clinic tenancies. HVAC scope spans base ventilation through clinical uplift.
- Mecca Brands. Retail-plus-treatment model with 70-plus stores nationally. Retail-dominant footprint with a clinical-uplift treatment zone at the back.
Day spa operators
- Endota Spa. Australia's largest day spa network, 70-plus locations. Brand-standard fit-out aligns with the NC-30 / 22–24 °C / 50% RH benchmarks set out earlier.
- Aurora Spa. Premium Melbourne day spa brand with flagship at St Kilda. Full wet-zone scope including hammam and hydrotherapy.
- Cinq Spa. Premium hotel-spa brand. HVAC integrates into the host hotel's mechanical services.
- Spa Anise. Regional Victoria spa brand at premium specification in non-metro markets.
Cosmetic injection and laser clinics
- Laser Clinics Australia. Largest cosmetic clinic chain in Australia, 200-plus clinics nationally, BGH Capital ownership. Clinical-uplift HVAC across every site.
- Australian Skin Clinics. Multi-site cosmetic and laser clinic chain at clinical-uplift specification.
- Clear Skincare Clinics. Multi-site cosmetic and skin clinic chain.
- Silk Laser Clinics. ASX-listed cosmetic and laser clinic chain (ASX:SLA).
- Profile. Premium cosmetic clinic brand operating in Australia and New Zealand.
- Brazilian Beauty. Multi-site beauty and cosmetic brand under Quadrant Private Equity. Combined salon-plus-clinic model.
Barber shops
- Eddy's Cutz. Multi-site Australian barber chain. Premium fit-out, NC-35 acoustic, retail product shelf.
- The Mens Lounge. Multi-site barber brand at premium specification.
- Razor. Multi-site barber chain with consistent fit-out specification.
Nail and tattoo studios
The Australian nail salon market is highly fragmented, with an estimated 5,000-plus operators and the vast majority owner-operated rather than franchised. Tier-one independent salons in metropolitan locations specify source-extract at every bench, sealed finishes and full AS 4674 compliance. Suburban kiosks often operate without dedicated source-extract, relying on shopping-centre house ventilation. State environmental health officers have begun inspecting nail salons more systematically, and the trend is toward universal source-extract installation at refurbishment. The tattoo studio market is even more fragmented and regulated state-by-state under skin-penetration codes; single-operator and small-team studios dominate, with HVAC scope identical regardless of size — ink-aerosol extract, negative-pressure room, AS 4674 surfaces.
11. Ductwork specification considerations
The ductwork specification for a personal services fit-out is shaped by three constraints: the available bulkhead depth in the tenancy envelope, the corrosion exposure at any branch downstream of a chemical source, and the leakage class required to maintain the design pressure relationships across multi-zone tenancies.
Bulkhead depth and slim-profile ductwork
Australian shopping-strip premises typically present 250 to 350 mm of bulkhead depth between the structural soffit and the architectural ceiling, with sprinkler heads, lighting trays, fire alarm conduit and other services competing for the same envelope. Ductwork in this depth is necessarily slim-profile — 200 mm or 250 mm rectangular section is common, transitioning to a deeper section once the duct exits the salon footprint and enters the shared building riser. The SBKJ SBAL-III rectangular line was designed specifically for this kind of slim-profile fit-out work, producing leakage-compliant rectangular duct at depths down to 200 mm in standard galvanised sheet.
Galvanised versus stainless
For general supply, return and ventilation duct across a personal services tenancy, galvanised steel is the default specification. Galvanised is durable, smooth-bore, accepts standard fittings, takes acoustic lining cleanly, and resists the typical solvent exposure at the airborne concentrations seen in the general room atmosphere. Where the branch is downstream of a concentrated chemical source — colour bar extract, nail-bench extract, perm-wave extract — 316 stainless is the upgraded specification, justified by lifetime corrosion resistance and easier deep-clean access. SBKJ rectangular ductwork plant fabricates both galvanised and 316 stainless from the same machine envelope by changing the coil.
Leakage class
Leakage class is the binding constraint on multi-zone tenancies where pressure relationships matter — clinical-uplift cosmetic injection rooms positive relative to corridor, wet zones negative relative to treatment rooms, retail floor positive relative to back-of-house. The Australian convention is to specify DW/144 Class B or SMACNA leakage Class 12 at minimum, with Class C / Class 6 at critical interfaces. The SBKJ SBAL-III rectangular line produces duct that satisfies Class B and Class 12 at fabrication, with the sealing accomplished on installation through proprietary cleat-and-mastic systems.
Source-extract branch integration
Source-extract arms and downdraft slots are the engineered termination of the chemical contaminant capture system at the bench. The branch ductwork connecting the hood to the main exhaust riser is the supplier's deliverable, and integration with the wider plenum is the fit-out builder's coordination scope. SBKJ slim-profile galvanised branches integrate cleanly through transition collars fabricated on the same line, and the standard suite includes 90-degree elbows, T-junctions, reducers and expansion pieces sized for the typical 200–300 L/s arm draw at 0.3 m/s capture velocity.
Acoustic lining
Treatment-room supply branches are acoustically lined for the run upstream of the room, typically with 25 mm fibrous acoustic insulation inside a perforated metal liner. The lining attenuates plant-side noise and prevents diffuser break-out from carrying into the room. The lining material is selected to be non-shedding, mould-resistant and AS 4674 cleanable, with the inner perforated liner preventing fibre release into the supply air.
12. Energy and sustainability
NABERS ratings apply to commercial tenancies at thresholds set by jurisdiction and tenancy type. Stand-alone salon and spa tenancies typically fall below the mandatory disclosure threshold, but operators in NABERS-rated buildings (shopping-centre tenancies, mixed-use developments) are subject to the building's overall rating and to landlord pressure to optimise tenant energy use. The HVAC engineering levers are familiar — variable-speed AHU fans, demand-controlled outside air linked to occupancy sensors, heat-recovery on the exhaust riser, LED lighting integration with the BMS, and recovery on the substantial heat rejection from hot stone and steam plant.
For nail salons specifically, the source-extract fan is the dominant energy consumer outside the AHU. EC fan motors with variable-speed control allow the extract rate to be modulated based on the number of active benches, rather than running all six benches at full draw whenever the salon is open. This is one of the highest-leverage energy optimisations available in a nail-tenancy fit-out, and it pays back within the first year on a busy site.
Day spas with significant wet-zone load — hammam, sauna, hydrotherapy — benefit from heat recovery on the exhaust riser. The exhaust from a hammam at 40 to 45 °C and 100% RH carries substantial thermal energy that can be recovered through a run-around coil or a plate exchanger and used to preheat the makeup air or to support the domestic hot water load. Payback on heat recovery for a flagship day spa is typically two to four years against a reference unrecovered baseline.
13. Commissioning and verification
Commissioning a personal services tenancy involves four distinct verifications beyond the standard mechanical commissioning. First, the AS 1668.2 outside-air rate is verified through hood traverses at every supply diffuser and confirmed against the design calculation. Second, the source-extract capture velocity is verified at every bench or bowl through smoke-tube or anemometer measurement at the hood face. Third, the pressure relationships across the tenancy are verified under design operating conditions, with the zone differentials confirmed against the BMS setpoints. Fourth, where the tenancy includes cosmetic injection or skin-penetration rooms, the room air-change rate, HEPA filter integrity (where present) and clean-zone surface integrity are verified to the clinical-uplift specification.
The commissioning report is the document that supports the environmental health officer's inspection on opening and the WHS regulator's inspection on any subsequent complaint. A salon, spa or clinic that has been commissioned to spec and documented properly is rarely the subject of an adverse inspection finding. A tenancy that has not been commissioned, or has been commissioned without documentation, is exposed to enforcement action that can result in trade restrictions and remediation orders.
14. How SBKJ supports salon, spa and clinic fit-outs
SBKJ Group is an Australian HVAC duct machinery supplier based in Box Hill North, Victoria, supplying ductwork plant to fit-out builders, sheet-metal contractors and franchise operations teams across the personal services sector. Our SBAL-III rectangular ductwork line was designed for the slim-profile, mixed-material, leakage-class-compliant work that salon, spa and clinic fit-outs demand. The same machine fabricates general galvanised supply duct, slim-profile rectangular branches for tight bulkhead depths, 316 stainless extract for nail-bench and wet-zone applications, and the transition collars and accessories that integrate source-extract arms and downdraft slots into the wider plenum.
For franchise operations teams scaling a national rollout — Endota Spa, Just Cuts, Laser Clinics Australia, Mecca Brands and the other multi-site operators referenced earlier in this guide — SBKJ provides a single ductwork specification baseline that travels with the brand standard from site to site. The same SBAL-III line at the fit-out builder's workshop produces consistent leakage-class-compliant duct for every store, regardless of state, regardless of bulkhead depth, regardless of branch material. Brand-standard consistency at the mechanical-services layer is the foundation of brand-standard experience at the customer layer.
For mechanical contractors and fit-out builders working a single tenancy at a time, SBKJ Group's Box Hill North office provides direct engineering support — sizing, drawing review, source-extract integration, leakage-class verification — on every project we are engaged in. Our engineers have 30-plus years of combined experience across personal services HVAC and a portfolio of installations spanning hair salons, beauty salons, day spas, barber shops, nail salons, laser clinics and cosmetic injection rooms across Australia.
Talk to an SBKJ engineer about your salon, spa or clinic fit-out →
FAQ
What is the AS 1668.2 ventilation rate for a hair or beauty salon in Australia?
AS 1668.2 applies V_p = 10 L/s/person plus V_a = 0.3 L/s/m² for hair and beauty floor space. The two are summed, then corrected for realistic occupancy diversity. For a 120 m² salon with 14 concurrent occupants, the calculation is 140 L/s plus 36 L/s = 176 L/s of outside air, before any local source-extract is added on top. Source-extract at colour bowls, nail benches and perm-wave stations is required as a separate engineering deliverable, not as a substitute for the general rate.
Do I need source extraction at every nail station?
Yes. Acetone, methyl methacrylate, ethyl methacrylate and toluene are emitted in concentrated plumes at each nail-tech bench. Safe Work Australia caps acetone at 750 ppm STEL, MMA at 50 ppm 8-hour TWA, and toluene at 50 ppm 8-hour TWA. Diluting these through general ventilation alone is uneconomic — a six-station nail salon would need 1,500 L/s of outside air. The correct solution is an articulated source-extract arm or downdraft slot at each station, sized for 0.3 m/s capture velocity at the bench, ducted to a dedicated exhaust riser.
What humidity and temperature targets apply to beauty treatment rooms and day spas?
Beauty treatment rooms are typically designed to 22–24 °C, 50% RH, NC-30 acoustic. Hammam runs at 60–65% RH internally with a 40% RH anteroom; sauna anteroom at 40% RH and 22 °C. Spa pool and hydrotherapy share the chloramine ventilation challenge with indoor aquatic facilities and need dedicated negative-pressure exhaust above the pool with makeup air introduced from the perimeter.
What changes for a cosmetic injection clinic versus a standard beauty salon?
Cosmetic injection clinics dispensing Schedule 4 substances under the Therapeutic Goods Order require clinical-grade treatment-room HVAC — 6 to 10 ACH, HEPA on supply at H13 minimum, dedicated extract not shared with retail return air, and slight positive pressure to corridor. Substance storage rooms are temperature-controlled at 2 to 8 °C with continuous monitoring. Laser hair removal and IPL rooms remain on ambient HVAC plus AS 1668.2 outside-air rates; the eye-protection controls are administrative rather than mechanical.
Why specify SBKJ galvanised ductwork over a generic alternative for salon and spa fit-outs?
Salon, spa and barber fit-outs are space-constrained, with typical 250–350 mm bulkhead depths in heritage shopping-strip premises. SBKJ SBAL-III rectangular ductwork produces DW/144 Class B and SMACNA Class 12 leakage-compliant duct at slim profiles down to 200 mm, in either galvanised or 316 stainless from the same machine envelope by changing the coil. Source-extract branches to colour bowls and nail benches integrate cleanly through transition collars fabricated on the same line.
