Industrial Laundry, Linen Hire, Hotel and Hospital Linen, Workwear, Uniform Rental and Dry Cleaning HVAC Duct Guide — AS 1668.2, AS 4254, AS/NZS 60079, AS/NZS 4187

Why industrial laundry HVAC duct is one of the most under-engineered systems in Australia

An industrial laundry plant looks, from the outside, like a simple business. Soiled linen, workwear or uniforms come in on a truck from a hotel, a hospital, a mining camp or a uniform-rental customer. The garments and flatwork are sorted, washed, extracted, dried, finished, folded, packed and trucked back out. A 50,000 kilogram per shift plant fits inside a single industrial-estate tilt-up panel building. The chemistry is detergent, bleach, softener and a few sanitising compounds. The equipment is large, mechanical and slow-moving. Margins are tight, contracts are price-sensitive and the workforce is heavily casual.

Underneath that surface, an industrial laundry is one of the most thermally aggressive, chemically diverse and dust-loaded process environments in the Australian commercial-building economy. The washer-extractor bank runs continuously at 70 to 95 degrees Celsius with chlorine bleach, peracetic acid disinfectant and a half-dozen surfactant and enzyme detergent streams. The tumble dryer bank runs at 80 to 150 degrees Celsius with LPG or natural gas combustion, lint-loaded exhaust and an open mechanical drum. The steam tunnel finisher hits 110 to 130 degrees Celsius with steam injection and a continuous moving conveyor of damp uniforms and workwear. The Calandra flatwork ironer — the heated 600 to 1,200 millimetre diameter roller bank that finishes hotel bedsheets, hospital flatwork, table cloth and napery — runs the roller surface at 180 to 220 degrees Celsius. The press station and hand iron finishing for uniform and workwear hits 150 to 180 degrees Celsius. And in the dry cleaning portion of the plant — whether the conventional perchloroethylene Perc legacy, the modern isoparaffin DF2000 or GreenEarth or Shell Sol replacement, the liquid CO2 transcritical machine or professional wet cleaning — the chemistry is a Group 2A carcinogen at the legacy end and a flammable solvent under AS/NZS 60079-10-1 Zone 1 at the modern replacement end. None of those parameters are gentle on HVAC ductwork.

Layered on top of the thermal and chemical load is the textile dust load. Every dryer cycle, every ironer pass, every folder operation throws cotton fibre, polyester microfibre, wool fluff and lint into the room air. Safe Work Australia workplace exposure standards cap respirable dust at 5 mg/m3 and inhalable dust at 10 mg/m3 over an eight-hour weighted average, and the medical literature on byssinosis (cotton-dust pulmonary disease) is a century old. The post-COVID Australian laundry worker also faces detergent enzyme allergic asthma (protease, amylase, lipase, cellulase), peracetic acid bronchial irritation, chlorine bleach mucosal damage and the rare but well-documented case of legionella from contaminated cooling water in plant utilities. NFPA 660 (2025) and AS 3957 both classify cotton, polyester and wool lint as combustible dust requiring engineered control. None of those parameters are gentle on the workforce.

And layered on top of the dust load is the hospital sterile linen overlay. A multi-site Australian industrial laundry operator — Spotless Group (the largest, now part of Downer EDI ASX:DOW with 80+ sites across NSW, Victoria, Queensland, Western Australia, South Australia, Tasmania, the ACT and the Northern Territory covering Sydney, Melbourne, Brisbane, Perth, Adelaide, Hobart and Darwin), Alsco Australia (Yarrambat Victoria HQ, Australian-owned biggest linen and uniform rental), Initial Hygiene Australia (Rentokil), or Aramark Australia — almost always runs at least one site that serves the hospital sterile linen market for NSW Health Pathology Laundry, Royal Melbourne, Royal Adelaide, Royal Brisbane, St Vincent's, Mercy Health, Calvary Health Care, Ramsay Health Care and Healthscope. That site sits under AS/NZS 4187 (reprocessing of reusable medical devices), ASHRAE 170 (ventilation of healthcare facilities) and the AHFG Australasian Health Facility Guidelines — a regulatory stack equivalent to a hospital operating theatre, layered on top of the industrial laundry stack already in place.

This guide is the design reference SBKJ engineers in Box Hill North Victoria use when briefed by mechanical consultants, multi-site facility operators and FIFO camp builders fabricating ductwork for Australian industrial laundry, linen hire, hotel and hospital linen, workwear and uniform rental and dry cleaning facilities. It walks through the regulatory framework, the process-train zone classification, the material selection, the construction-class decision, the dust and combustion and solvent-vapour safety engineering, the fabrication sequence on SBKJ SBAL-V, SBAL-III, SBSF-1525, SB-ZF1500, SBFB-1500, SBPC1500, SBLR-600 and SBTF-1500/1602/2020 machinery, the commissioning protocol and the operational handover. It is not a substitute for a registered mechanical engineering design, an AS/NZS 4187 compliance review by an accredited healthcare design consultant or a project-specific NSQHS accreditation cycle on the hospital-segment portion of a multi-site laundry estate.

The Australian operator landscape — Spotless Group Downer EDI commercial laundry

Spotless Group is the largest commercial laundry, catering and facility-services operator in Australia. Acquired by Downer EDI (ASX:DOW) in 2017 and now reporting through the Downer Facilities segment, Spotless runs more than 80 laundry sites across every state and territory: New South Wales (multiple Sydney metropolitan and regional sites), Victoria (Melbourne and regional), Queensland (Brisbane, the Gold Coast, Cairns and Townsville), Western Australia (Perth and the Pilbara FIFO support sites), South Australia (Adelaide), Tasmania (Hobart and Launceston), the Australian Capital Territory (Canberra) and the Northern Territory (Darwin and Alice Springs). The Spotless portfolio covers hospital linen (NSW Health Pathology Laundry, the Royal Melbourne, the Royal Adelaide, the Royal Brisbane, the St Vincent's network, the Mercy Health network, the Calvary Health Care network, the Ramsay Health Care private network and the Healthscope private network), hotel linen (Sheraton, Hilton, Marriott, Accor, IHG, Wyndham and the Australian boutique segments), workwear and uniform rental (cross-over with Spotless Workwear and the Bisley, KingGee, Hard Yakka, Stubbies, Workscene and Hi-Vis / FR Fire Retardant ranges), aged care and disability linen (cross-over with the NDIS SDA segment) and the catering-laundry combined hospitality contracts.

Spotless laundry sites are typically 4,000 to 12,000 square metres of process floor with 50 to 200 kilogram Pellerin Milnor, Kannegiesser, Jensen, Lavatec or Speed Queen washer-extractor banks (10 to 30 machines per site depending on throughput), a matching tumble dryer bank, two to four steam tunnel finisher lines, two to six Calandra flatwork ironers, a folding and packaging line, a chemical dosing room running Ecolab or Diversey systems, a steam boiler plant (typically gas-fired with electric backup), a FOG trap and trade-waste interface, an amenities and locker zone for 50 to 200 workers per shift, and a route-despatch dock with refrigerated linen trucks (linen for hospital is cold-chain managed under ASHRAE 170 isolation regime to limit microbial growth). The HVAC duct package on a typical Spotless site runs 8,000 to 25,000 kilograms of fabricated steel duct across the process floor, the plant rooms, the chemical dosing and the amenities envelope, with 316L stainless on the steam tunnel finisher exhaust, the Calandra ironer extract, the chemical dosing exhaust and the hospital sterile linen lane (where the site serves that market).

SBKJ engineering supplies SBAL-V auto duct line capacity to Spotless site builds and refurbishments for the bulk galvanised supply and return; SB-ZF1500 stitchwelder capacity for the 316L stainless welded steam tunnel finisher and ironer exhaust; SBSF-1525 round tube flanging for the fire-rated 250C / 2 hour exhaust connections; SBFB-1500 spiral former for the lint and microfibre dust conveying to the central baghouse; SBPC1500 plasma cutter for stainless hole and access panel cutouts; and the SBLR-600 / SBTF series welders for the welded stack and chemical sterilant exhaust finishing. The site-specific scope varies by which segment Spotless is running on the site (hotel, hospital, workwear, FIFO logistics support) but the SBKJ machine portfolio covers the full range.

Alsco linen and uniform rental — Australian-owned biggest

Alsco Australia is the largest Australian-owned linen and uniform rental operator, headquartered at Yarrambat in north-east metropolitan Melbourne and operating across Sydney, Melbourne, Brisbane, Perth and Adelaide with regional satellite depots. The Alsco product line covers commercial mat and floor care (entrance mats, scraper mats, anti-fatigue), washroom services (paper, soap, sanitary, air freshener), linen rental (hotel, hospitality, food service), uniform rental (food service, manufacturing, healthcare, mining), and the cross-over corporate workwear and FR Fire Retardant uniform segment for mining and oil and gas customers.

Alsco laundry sites are operationally similar to Spotless — washer-extractor banks, tumble dryer banks, steam tunnel finisher, ironer line, folding and packaging, chemical dosing, steam boiler — but with two distinct overlays. First, the uniform and workwear segment runs FR Fire Retardant fabric (treated cotton, modacrylic, Nomex aramid blends) through a separate climate-controlled zone where the FR coating chemistry is not contaminated by general detergent and where the inspection-and-repair workflow is integrated. FR fabric handling has its own chemical resistance and fibre-shedding profile distinct from cotton terry hospital linen. Second, the route-rental business model (Alsco delivers in clean, picks up dirty, repairs and replaces damaged inventory) drives a higher inspection and QC overlay than a one-way hospital linen contract. RFID tagging and barcode scanning are integrated into the folding line for fleet inventory traceability.

SBKJ engineering supplies Alsco sites with the same SBAL-V, SBSF-1525, SB-ZF1500, SBFB-1500 and SBPC1500 machine portfolio as Spotless, with particular attention to the FR fabric handling zone (separate exhaust to avoid cross-contamination of FR coating chemistry) and the inspection-and-repair zone (lower dust load, tighter humidity control for the QC and repair workforce). The Yarrambat HQ site is the Alsco flagship and the operational benchmark for the multi-site estate.

Initial Hygiene, Aramark, Ecolab, Diversey and the chemical supply layer

Initial Hygiene Australia (the linen, washroom and industrial-service division of Rentokil) operates a smaller laundry footprint than Spotless and Alsco but covers Sydney, Melbourne, Brisbane, Perth and Adelaide with focus on washroom services, mat and floor care, linen and industrial. Aramark Australia is the local arm of the US-headquartered facilities, laundry, catering and uniform group with strong cross-over into government, defence and remote-camp contracts. Both run the same core wash-dry-finish-fold process as Spotless and Alsco with smaller sites and tighter integration with the parent facility services business.

Ecolab Australia and Diversey Australia (merged with Sealed Air's commercial laundry chemical line in 2023 under Ecolab's broader consolidation) supply the chemical layer that runs across all of the above operators. Ecolab and Diversey dosing systems sit in a dedicated chemical room on every commercial laundry site, with bulk tanks of detergent, bleach (sodium hypochlorite), softener (cationic surfactant), peracetic disinfectant (for hospital and food-service linen), enzyme blends (protease, amylase, lipase, cellulase), pH neutraliser, sour (mild acid for final rinse pH correction) and optical brightener. Each tank is dosed via metering pump through chemical-resistant pipe (PVC, PVDF or 316L stainless) to the relevant washer-extractor or finishing line.

The HVAC role in the chemical dosing room is to maintain -5 Pa negative pressure to the surrounding plant (so that any vapour or aerosol leak drifts into local exhaust rather than into the production floor), local exhaust ventilation at every pump and tank fill point in 316L stainless duct, continuous chlorine and peracetic acid vapour monitoring at breathing height (Safe Work Australia WES: chlorine 0.5 ppm STEL, peracetic acid 0.4 ppm STEL), and a chemical-resistant exhaust fan and stack discharging clear of any intake. Enzyme allergen control adds a HEPA-grade pre-filter to capture the enzyme particulate before discharge (the enzyme is the sensitiser, not the bulk chemical vapour). SBKJ supplies the chemical dosing room exhaust ductwork in 316L stainless on the SB-ZF1500 stitchwelder for the welded sections and the SBFB-1500 spiral former for any round trunk to the rooftop discharge.

Compass Group, Sodexo, ISS and the FIFO remote mine-site laundry — ESS Sodexo Compass ISS

Compass Group Australia, Sodexo Australia and ISS Group Australia run the FIFO remote-camp catering and facility-services business across the Australian resources sector, with cross-over laundry as part of the camp service offering. ESS Support Services (Compass Group's specialist remote-camp brand), Sodexo Energy and Resources, Compass Remote and ISS Group all operate camp laundry plants at Pilbara iron ore (BHP, Rio Tinto, Fortescue), Bowen Basin coal (BMA, Glencore, Anglo American), Surat Basin coal and gas (Santos, Origin, Shell QGC), Galilee Basin coal (Adani / Bravus), Kalgoorlie and the Goldfields gold (Northern Star, Evolution Mining, Gold Fields), Western Plains uranium (Olympic Dam BHP, Beverley Heathgate), and the various offshore oil and gas and onshore LNG support camps.

The FIFO modular laundry is a containerised plant designed to be craned onto a remote pad, plumbed into the camp water and power infrastructure, and operated for a 5 to 10 year camp life with minimal site labour. The 6 or 12 metre shipping container envelope contains a 50 to 100 kilogram washer-extractor (Pellerin Milnor or Speed Queen commercial-grade), one or two tumble dryers, a folding station and a small finishing line. Some larger camps run a multi-container fit-out with separate wash, dry and finish containers connected by an overhead conveyor. The HVAC design parameters are identical to a metropolitan plant compressed into the container envelope:

• Ambient envelope: 45-degree Celsius peak summer ambient at Pilbara and Kalgoorlie sites, -5 degrees winter at Bowen Basin and Surat Basin. The HVAC plant has to size for both extremes and the container shell has to be fully insulated.
• Dust ingress: red iron-ore dust loading at the Pilbara, sandstorm-driven inland dust at Olympic Dam and the Goldfields. Intake pre-filter staging is G4 + F7 + F9 ahead of any HEPA terminal. The intake hood is hooded and louvered to deflect bulk dust, and the pre-filter is maintenance-accessible from outside the container.
• Off-grid power: diesel genset primary, solar with battery secondary, town power (where available) tertiary. The HVAC plant draws from all three with auto-changeover and an energy management ISO 50001 compatible BMS.
• Water recycling: remote camps run zero-liquid-discharge or near-ZLD water management with recycled bore water at high TDS (total dissolved solids). The washer-extractor and the steam boiler both run on treated water with periodic regeneration of the softener and the reverse-osmosis polishing. The FOG trap interface is fully sealed and discharges through trade-waste tankers when on-camp polishing is not sufficient.
• Noise envelope: the camp sleeping accommodation sits a few hundred metres from the laundry. Double-skin acoustic lining on supply trunks, attenuator banks on intake and exhaust, NC-35 maximum at the camp boundary. SBKJ supplies the double-skin duct on the SBAL-V auto duct line with internal acoustic lining factory-fitted.
• Redundancy: N+1 on tumble dryer exhaust and steam tunnel finisher exhaust; loss of exhaust shuts the wash and dry cycle (the linen has nowhere to discharge moisture and lint and would condense inside the container). N+1 on the boiler. N+1 on the chemical dosing pumps.
• Asset life: 5 to 10 years on a single camp pad, then craned out and re-deployed to the next camp. The HVAC ductwork has to survive disassembly, road transport and re-assembly without leakage failure. SBAL-V seam strength and SBSF-1525 flange integrity matter materially.

SBKJ engineering supplies the FIFO modular laundry HVAC duct in factory-finished 316L stainless or galvanised G90 on the SBAL-V auto duct line with double-skin acoustic option, with the spiral lint conveying on the SBFB-1500, the welded steam tunnel finisher and ironer exhaust on the SB-ZF1500, and the fire-rated dryer exhaust on the SBSF-1525. The complete duct kit is shipped to the modular fabricator's yard (commonly in Perth, Brisbane or Newcastle), assembled inside the container shell on the fabrication line and craned out to the remote camp as a finished asset.

Hospital sterile laundry — AS/NZS 4187 and ASHRAE 170 negative pressure isolation

The hospital sterile linen segment of an industrial laundry is regulated as if it were an operating theatre adjunct. Soiled linen from a hospital comes back to the laundry contaminated with blood, tissue, body fluids, faecal matter and the full microbial load of the patient population — including methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococci (VRE), Clostridioides difficile, COVID-positive respiratory secretions, hepatitis B and C, HIV, Brucella, Salmonella, E. coli and the various zoonotic and tropical agents that an Australian tertiary teaching hospital sees in a year. AS/NZS 4187 (reprocessing of reusable medical devices) covers the surgical instrument side of the laundry-CSSD adjacency, and ASHRAE 170 (ventilation of healthcare facilities) and the AHFG cover the linen side.

The pressure cascade across the hospital sterile linen lane runs:

• Soil receiving and infectious linen sorting (negative -5 to -10 Pa): 12 ACH minimum single-pass HEPA H13 exhaust, no recirculation back into the building, MERV 13 minimum make-up supply, 22 to 24 degrees Celsius and 40 to 60 percent humidity. Workers wear gowns, gloves and N95 respirators per AS/NZS 1716. The exhaust discharges vertically at minimum 3 metres above the roof and 8 metres horizontal from any intake.
• Wash and extract (neutral): high-temperature wash at 70 to 95 degrees Celsius with chlorine bleach (Cl2 0.5 ppm STEL workplace exposure) or peracetic acid (0.4 ppm STEL) disinfectant kills the bulk microbial load. The pressure relationship is neutral because the wash zone is closed-machine.
• Dry and finish clean side (positive +5 to +10 Pa): 6 to 12 ACH HEPA H13 supply, 30 to 60 percent humidity, smooth cleanable wall surfaces, minimum joints. Workers wear scrubs and gloves. The pressure cascade ensures any breach of the wash machine seal drifts back into the soiled lane, not forward into the clean lane.
• Folding and packaging clean side (positive +5 to +10 Pa): same parameters. RFID and barcode tagging integrated for fleet traceability. The clean folded linen is packed into sealed wrap or bag for delivery.
• Cold-chain staging and route despatch (neutral to +5 Pa, 12 to 18 degrees Celsius): the clean wrapped linen is held in cool conditions to inhibit any residual microbial growth between fold and delivery. The delivery truck is refrigerated for hospital linen routes (Spotless, Alsco and the dedicated hospital linen plants run refrigerated linen trucks per the contract).
• CSSD adjacent processing (where co-located): autoclave (121 degrees Celsius, 30 minutes saturated steam), ethylene oxide (EtO) chamber under AS/NZS 60079 Zone 1, hydrogen peroxide plasma (Sterrad) under chemical sterilant exhaust, ortho-phthalaldehyde (OPA) bath under chemical sterilant exhaust, peracetic acid bath under chemical sterilant exhaust, and gamma irradiation (off-site at ANSTO or equivalent, not in the laundry). Each modality has dedicated 316L stainless exhaust ductwork on the SBKJ SB-ZF1500 stitchwelder with continuous welded seams, SMACNA Seal Class A integrity and SBSF-1525 flange detail.

SBKJ engineering practice is to specify Type 316L stainless steel 1.5 millimetre minimum throughout the hospital sterile linen lane: the soil receiving negative-pressure exhaust trunk, the wash-zone supply (because the moisture and detergent vapour environment is aggressive even though chemically benign), the clean-side supply (where the HEPA H13 terminal integrity matters), the chemical sterilant exhaust on the CSSD adjacent processing, and the cold-chain staging refrigeration ductwork. Galvanised steel is acceptable only on the bulk return and the corridor general supply outside the sterile linen envelope. SMACNA Seal Class A applies throughout. The pressure cascade is continuously logged on the BMS with alarming at 50 percent of design and 25 percent of design as warning and critical.

Perchloroethylene Perc dry cleaning Zone 1 phasing — the killer chemistry

Perchloroethylene (Perc, tetrachloroethylene, PCE) is the legacy dry cleaning solvent that has defined the industry for sixty years and is now being progressively phased out across Australia, Europe and the United States. The case against Perc is:

• Carcinogenicity: IARC Group 2A (probably carcinogenic to humans), with the strongest evidence on bladder cancer in occupationally exposed workers.
• Hepatotoxicity: well-documented liver damage at chronic occupational exposure.
• Nephrotoxicity: kidney damage, particularly the proximal tubule, again at chronic occupational exposure.
• Central nervous system effects: acute CNS depression at high exposure, chronic neurobehavioural deficit at moderate occupational exposure.
• Reproductive and developmental toxicity: miscarriage and developmental risk in pregnant workers and partners of exposed workers.
• Environmental persistence: Perc is a dense non-aqueous phase liquid (DNAPL) that contaminates soil and groundwater under any historic dry cleaner site for decades.

Safe Work Australia workplace exposure standard sits at 25 ppm 8-hour TWA and 100 ppm STEL — numbers that are conservative compared with the 1990s benchmark of 100 ppm TWA but still permissive compared with the 2020s European Union Reach restriction (Perc banned for professional and consumer use under EU REACH from 2025 with limited transition allowances) and the United States EPA TSCA Risk Evaluation finding (Perc to be progressively restricted under the Toxic Substances Control Act with proposed prohibition on dry cleaning use). New South Wales EPA tightening of POEO (Protection of the Environment Operations Act) licensing of dry cleaning sites in NSW has driven multi-site operators to commit to Perc-free fleets by 2030 at the latest. The Drycleaners Institute of Australia (DIA) and the Cleaning and Linen Industry Council (CLIC) have published industry transition guidance.

The four replacement chemistries that an Australian dry cleaner can choose from in 2026 are:

Isoparaffin hydrocarbon solvent (DF2000, GreenEarth, Shell Sol, Exxsol DSP)

Isoparaffin hydrocarbon solvents — ExxonMobil's DF2000, Procter and Gamble licensee GreenEarth's siloxane decamethylcyclopentasiloxane D5, Shell Chemical's Shell Sol K, Exxsol DSP and the various branded analogues — sit at 200 ppm 8-hour WES under Safe Work Australia. The replacement chemistry is hydrocarbon-based, less toxic than Perc by every measure (no IARC classification, no DNAPL groundwater contamination risk), and broadly process-compatible with the existing dry cleaning machine population (some replacement, mostly retrofit). The trade-off is flammability: isoparaffin solvents are flammable per AS 1940 and the dry cleaning machine envelope is classified AS/NZS 60079-10-1 Zone 1 inside the immediate machine and Zone 2 to the room walls. The HVAC ductwork in the immediate envelope is spark-resistant aluminium or non-sparking bronze fittings; the broader machine room is conventional 316L stainless or galvanised; the vent stack is 316L stainless welded on the SBKJ SB-ZF1500 stitchwelder with continuous TIG-welded seams from the SBLR-600 longitudinal welder and SBSF-1525 flanged transverse joints.

Liquid CO2 transcritical

Liquid CO2 transcritical dry cleaning machines are the cleanest replacement from a worker-exposure standpoint — the cleaning medium is liquefied carbon dioxide at high pressure (transcritical state above the critical point at 31 degrees Celsius and 73 bar), and at end of cycle the CO2 is recovered and recompressed for re-use with minimal vent loss. There is no flammable solvent, no IARC carcinogen classification, no DNAPL groundwater risk and no AS/NZS 60079 Zone classification. The trade-off is capital cost (the machines are 3 to 5 times the capital cost of an equivalent isoparaffin or Perc machine) and the high-pressure pipe and vessel infrastructure (the machine, the recovery vessel, the storage vessel and the interconnecting pipework all sit under AS 4036 and AS 4037 pressure vessel regulation). The HVAC role is oxygen-deficiency monitoring at breathing height in the machine room (CO2 asphyxiation is the failure mode; a vessel leak displaces oxygen) and conventional 316L stainless or galvanised ductwork for the general machine room supply and return. There is no vent stack because there is no atmospheric vent in normal operation.

Professional wet cleaning

Professional wet cleaning is the controlled-aqueous alternative — a specialised washer-extractor running on water with formulated detergent, specialised softener and tightly controlled mechanical action (low rotational speed, controlled temperature, controlled spin extract) followed by a controlled finishing process (tunnel finisher and press) that restores the garment shape and hand-feel. The chemistry is detergent and softener, no solvent. The HVAC requirement is identical to a conventional commercial washer-extractor line plus the tunnel finisher and press — 316L stainless on the finisher exhaust on SB-ZF1500, galvanised or stainless on the wash zone supply and return, no Zone classification. The trade-off is process limitation: not every garment that can be Perc or isoparaffin dry-cleaned can be wet-cleaned (some wool, some silk, some structured tailoring may shrink or distort), and the operator skill ceiling is higher.

Retrofitted Perc machines with fifth-generation solvent recovery

For Australian dry cleaning sites that are not yet ready to migrate — typically older multi-shop chains or single-shop independents with significant capital tied up in installed Perc machines — the bridging option is to operate the existing Perc machine fleet with closed-loop fifth-generation solvent recovery: refrigerated condenser at the machine vent recovering Perc vapour, activated carbon adsorber polishing the residual vent stream, and a fully sealed solvent loop with minimal atmospheric release. The HVAC ductwork on a fifth-generation Perc machine is 316L stainless 1.5 millimetre minimum on the SBKJ SB-ZF1500 stitchwelder with continuous TIG-welded seams, AS/NZS 60079 Zone 1 classification of the machine envelope, continuous Perc vapour monitoring (PID or photo-ionisation detector calibrated to Perc, logged to BMS with alarm at 25 ppm TWA and 100 ppm STEL), and a discharge stack terminating clear of any intake. SBKJ designs the duct shell for swap-out compatibility with the isoparaffin and liquid CO2 retrofits so that the operator can migrate without re-fabricating the entire ductwork package.

SBKJ engineering practice on a new Australian dry cleaning ductwork scope in 2026 is to design as if Perc will be banned within the asset life and to make the duct shell, the vapour recovery hardware envelope, the vent stack and the BMS architecture swap-out compatible with isoparaffin, liquid CO2 and wet cleaning replacements. The 316L stainless construction is non-negotiable for any solvent vent. The SB-ZF1500 stitchwelder, the SBLR-600 longitudinal welder and the SBSF-1525 round tube flanging machine are the three SBKJ machines that produce the welded stack. The SBPC1500 plasma cutter handles the hole and access panel cutouts. The whole package is SMACNA Seal Class A integrity tested before commissioning.

Australian textile dust lint cotton wool — NFPA 660 and AS 3957

Every industrial laundry is a continuous textile-dust generator. The dryer tumbles damp linen at 80 to 150 degrees Celsius and throws cotton fibre and polyester microfibre out through the lint trap into the room air; the ironer roll surface picks up lint from the flatwork passing over it and sheds it back into the room; the folder and packaging line generates a low-velocity but continuous fibre cloud; and the soil receiving and sorting lane releases fibre, lint and dust from the incoming garment load before any wash has happened. The accumulated dust load inside the building over a shift is substantial and visible — the rafters and the supply diffuser faces are coated in lint after a week of operation without cleaning, and the dryer lint trap collects litres of accumulated fibre per machine per shift.

Safe Work Australia workplace exposure standards on dust:

• Respirable dust: 5 mg/m3 8-hour TWA — the fraction small enough to reach the gas-exchange region of the lung (less than approximately 4 micrometres aerodynamic diameter).
• Inhalable dust: 10 mg/m3 8-hour TWA — the fraction small enough to enter the upper airway (less than approximately 100 micrometres aerodynamic diameter).
• Cotton dust (specific): historically managed under the byssinosis-control regime that the Australian textile industry has largely phased out (cotton dust remained a control parameter under earlier WES schedules but is now folded into the general dust standard with industry-specific guidance).

The clinical conditions associated with chronic laundry dust exposure are non-specific occupational asthma, chronic rhinitis, allergic alveolitis (hypersensitivity pneumonitis), occupational COPD progression and the historically described byssinosis (Monday-fever, chest tightness on return to work after a weekend break). Detergent enzyme exposure overlays additional sensitisation risk (see the next section).

The two governing engineering control standards are:

• NFPA 660 (2025 consolidated combustible dust standard): the US National Fire Protection Association combustible dust standard, consolidated in 2025 from the prior NFPA 654, NFPA 484, NFPA 61, NFPA 664 and other industry-specific dust standards. NFPA 660 classifies cotton fibre, polyester microfibre, wool fluff and the mixed textile dust generated in an industrial laundry as combustible dust requiring engineered control on source capture, conveying duct, dust collector (baghouse or cyclone), deflagration venting and explosion isolation. NFPA 660 alignment is the de facto international benchmark.
• AS 3957: the Australian dust hazard practice standard, broadly aligned with NFPA 660 and providing the local-language engineering guidance.

The engineered control regime on a properly designed industrial laundry is:

• Source capture at every dryer lint trap: hooded lint trap with direct connection to the spiral conveying duct, eliminating the open-room ejection of lint.
• Source capture at every ironer roll exit: low-velocity textile-friendly hood across the full roller width capturing the lint released by the heated roller surface.
• Source capture at folding and packaging lines: low-velocity downdraft or canopy hood across the working surface.
• Spiral conveying duct: round spiral duct produced on the SBKJ SBFB-1500 spiral former at 18 to 22 metres per second conveying velocity (high enough to maintain particle suspension, low enough to avoid duct erosion), galvanised G90 or 316L stainless depending on the chemical overlay, with cleanout doors at every change of direction.
• Cyclone pre-separator: a high-efficiency cyclone removes the bulk of the lint and microfibre before the baghouse, extending baghouse filter life.
• Baghouse with HEPA polishing: the baghouse captures the residual fine dust; HEPA polishing on the discharge ensures the air returned to the room (or vented to outdoor) is below the WES limit.
• Deflagration venting: the baghouse and the cyclone are fitted with deflagration vents per NFPA 660 sized to relieve the worst-case dust explosion pressure rise. The vents face a safe blast direction (open courtyard, roof, or away from any occupied space).
• Explosion isolation: the upstream spiral duct is fitted with a passive isolation valve or chemical isolation barrier per NFPA 660 to prevent flame propagation back into the building.
• Static-bonding to ground: the entire spiral duct, the cyclone, the baghouse and the connecting flexible sections are continuously bonded to ground to dissipate any static charge buildup. Conductive flexible connections (no plastic flex hose). Ground-fault monitoring on the bond integrity.

SBKJ supplies the spiral conveying duct on the SBFB-1500 spiral former, the cyclone and baghouse interfaces on the SB-ZF1500 stitchwelder, the SBSF-1525 round tube flanging for joint detail, and the SBPC1500 plasma cutter for the cleanout door and inspection-port cutouts. The complete duct package is leakage tested to AS 4254 Class B or C and SMACNA Seal Class A.

Detergent enzyme allergen control — protease amylase lipase cellulase

Modern commercial laundry detergent uses enzymes to break down specific soil components: protease for protein soils (blood, food, body fluids), amylase for starch (food, paste), lipase for fat and oil (food, sebum, machinery grease) and cellulase for cotton fibre conditioning (improves cotton hand-feel and removes pilling). The enzyme concentration in the working detergent stream is sufficient to cause respiratory and dermal sensitisation in workers exposed via dosing-pump leaks, batch tank fill operations, bulk powder transfer, dryer lint inhalation (where enzyme-treated linen has shed enzyme-bound fibre) and direct skin contact with detergent splash.

The clinical picture in sensitised laundry workers is:

• Occupational asthma: wheeze, chest tightness, cough, dyspnoea, work-correlated and improving on absence from work.
• Allergic rhinitis: nasal congestion, rhinorrhoea, sneeze.
• Allergic contact dermatitis: erythema, vesicle, scaling on hands, forearms and exposed skin.
• Hypersensitivity pneumonitis (chronic): diffuse interstitial lung disease with restrictive pattern on lung function testing, equivalent to baker's asthma in the bakery industry.
• Cross-reactivity: sensitised workers may react to multiple enzymes in the same blend, and the cross-reactivity to dust mite, mould and pollen allergens is recognised.

Safe Work Australia does not publish a specific WES for individual laundry enzymes, recommending instead control to the lowest reasonably achievable. The industry-accepted engineering benchmark for enzyme particulate at breathing height is 60 ng/m3 (nanograms per cubic metre) measured by enzyme-specific immunoassay — a level that requires meaningful local exhaust ventilation at every enzyme handling point. The engineered control regime is:

• Closed-loop dosing systems: the dominant Ecolab and Diversey commercial dosing systems are sealed and pump-fed from sealed drums or totes, with minimal open transfer. The exhaust requirement is concentrated at the pump-head and the tank fill point rather than across the whole chemical room.
• Local exhaust ventilation at every pump and tank fill: 316L stainless or chemical-resistant PVC duct with face velocity 0.5 to 0.7 metres per second at the capture point, sized to the dosing-system manufacturer's specification.
• HEPA pre-filter on the discharge: the enzyme is a particulate sensitiser, not a volatile, so HEPA filtration on the discharge captures it before atmospheric release. HEPA H13 (per ISO 29463) minimum.
• Negative pressure chemical room: -5 Pa relative to the surrounding plant ensures any leak drifts into local exhaust rather than into the production floor.
• PPE backup: P2 respirators, chemical splash gloves and chemical splash apron per AS/NZS 1716 for any open-handling task.
• Health surveillance: baseline spirometry and skin assessment on hire, annual repeat for exposed workers, and specific allergen IgE testing on symptomatic workers.

SBKJ supplies the chemical room exhaust ductwork in 316L stainless on the SB-ZF1500 stitchwelder with continuous TIG-welded seams from the SBLR-600 longitudinal welder, SBSF-1525 flange detail at the transverse joints, and SBPC1500 plasma cutter cutouts for the HEPA pre-filter housing access. The discharge runs to a rooftop stack with the HEPA polishing pre-filter inline. The chemical room itself is sealed to the surrounding plant with continuous-seal door and dampers.

Calandra flatwork ironer 180-220C — the hottest single asset in the laundry

The Calandra flatwork ironer (sometimes spelled Calender ironer; "Calandra" is the trade-name spelling preserved in the Italian and Spanish-speaking industry segments) is the heated roller bank that finishes hotel bedsheets, hospital flatwork, table cloth, napery, pillowcase and the broad flat-fabric output of a commercial laundry. The ironer comprises one to five heated cylindrical rollers (typically 600 to 1,200 millimetres diameter) arranged in series or parallel with a transport belt that carries the damp sheet through the heated nip, drying and pressing it in a single pass. Surface temperatures run 180 to 220 degrees Celsius, achieved by saturated steam (typical at 12 to 16 bar saturation pressure giving 188 to 200 degrees Celsius surface), thermal oil (higher temperature ceiling, up to 220 degrees Celsius at the roller surface) or direct gas firing on smaller machines. Kannegiesser, Jensen, Lavatec, Pellerin Milnor, Goodway and Foltex are the dominant ironer manufacturers in the Australian commercial laundry market.

The HVAC and exhaust design parameters for the Calandra ironer are:

• Exhaust temperature: 80 to 120 degrees Celsius typical in the exhaust duct downstream of the ironer, peaking at 150 degrees Celsius during start-up or under fault conditions. The duct must withstand continuous 150 degrees Celsius and short-term excursions to 250 degrees Celsius during an over-temperature event.
• Moisture loading: the wet sheet entering the ironer at 30 to 50 percent residual moisture from extraction flashes most of that moisture in the ironer nip. The exhaust is steam-saturated at the discharge and condenses readily in any cold spot. Continuous drip points and condensate drains on the duct low points.
• Lint loading: as discussed under NFPA 660 above, the heated roller surface picks up cotton and polyester fibre from the flatwork and sheds it into the exhaust. Source capture hood at the roller exit connects into the spiral conveying duct on the SBFB-1500 spiral former running to the central baghouse.
• Fire rating: the exhaust duct from the ironer to the rooftop stack runs through the plant building and is fire-rated to 250 degrees Celsius for 2 hours per AS/NZS 1530.4 where it crosses a fire-rated zone. SBKJ supplies the fire-rated construction on the SBSF-1525 system.
• Material: Type 316L stainless steel 1.5 millimetre minimum on the SBKJ SB-ZF1500 stitchwelder with continuous TIG-welded longitudinal seams from the SBLR-600 longitudinal welder and SBSF-1525 flanged transverse joints. The combination of high temperature, moisture and lint makes any galvanised duct a corrosion failure within 2 to 5 years; 316L stainless is the industry standard.
• Velocity and sizing: 12 to 18 metres per second in the trunk, 18 to 22 metres per second in the spiral lint conveying section, sized to the ironer manufacturer's exhaust flow specification (typically 2,500 to 6,000 cubic metres per hour per ironer depending on capacity).
• Discharge: rooftop stack terminating vertically upward at minimum 3 metres above roof and 8 metres horizontal from any outdoor air intake, with the lint baghouse and cyclone pre-separator integrated on the discharge path.
• NFPA 86 alignment: the ironer is treated as an industrial oven under NFPA 86 (the US National Fire Protection Association ovens and furnaces standard). The legal driver in Australia is the gas safety act and AS 4036 / AS 4037 pressure vessel regulation for the steam side, but NFPA 86 alignment on combustion safety and exhaust integrity is the international engineering benchmark.
• Burner gas safety: where the ironer is gas-fired (LPG or natural gas) rather than steam-heated, the burner room has CH4 1.25 percent LEL monitoring on the gas supply, CO monitoring downstream of combustion (Safe Work Australia WES: CO 30 ppm STEL), automatic shutdown on burner trip and gas isolation on building emergency stop.

SBKJ supplies the complete Calandra ironer exhaust ductwork from the source capture hood through the spiral lint conveying duct, the cyclone pre-separator interface, the baghouse interface, the trunk to the rooftop stack and the stack itself in 316L stainless on the SB-ZF1500 stitchwelder, SBFB-1500 spiral former, SBSF-1525 flanging, SBLR-600 longitudinal welding and SBPC1500 plasma cutting. The complete package is leakage tested to AS 4254 Class B or C and SMACNA Seal Class A.

Hotel linen contracts — Sheraton Hilton Marriott Accor IHG Wyndham

The hotel linen segment of an Australian industrial laundry serves a narrow range of large multi-property chains: Marriott International (Sheraton, Marriott, Westin, Le Méridien, W, Four Points, Element and the Bonvoy portfolio), Hilton (Hilton, Conrad, DoubleTree, Hampton, Hilton Garden Inn), Accor (Sofitel, Pullman, Novotel, Mercure, ibis, Mantra, Peppers, Tribe), InterContinental Hotels Group (InterContinental, Crowne Plaza, Holiday Inn, Indigo, voco), Wyndham (Wyndham, Ramada, Days Inn), and the boutique and Australian-domestic chains (QT, Ovolo, Veriu, Crystalbrook, Punthill, Lancemore, Mantra cross-over). The product mix is hotel bedsheet, pillowcase, duvet cover, bath towel, hand towel, face towel, bath mat, table cloth, napery, kitchen apron, chef coat and the cross-over food-service uniform.

Hotel linen is less infection-control-sensitive than hospital linen but more cosmetically demanding — the bedsheet finish, the towel softness and the napery presentation drive guest satisfaction scores that drive the hotel chain's contract renewal decision. The HVAC implications are:

• Humidity control on folding and packaging: 50 to 65 percent relative humidity at 20 to 24 degrees Celsius in the folding zone maintains fabric hand-feel and prevents static cling. Outside that band the workforce complains and the fabric quality drops.
• Temperature control on the wash and finish: bedsheet whiteness depends on consistent wash chemistry and consistent rinse temperature. The HVAC plant supplies clean conditioned air to the wash zone supply diffusers and to the chemical dosing room to maintain stable chemistry.
• Sheridan, Canningvale, Bambury, Logan and Mason, Royal Doulton linen segments: the premium linen brands (Hanes Brand-owned Sheridan, Australian Canningvale, Bambury, Logan and Mason, Royal Doulton) supply the cotton-rich and Egyptian-cotton-rich hotel inventory that is most sensitive to wash chemistry and finishing temperature. The HVAC plant feeds into a tight-tolerance process.
• Route logistics: hotel linen is delivered overnight or early morning into the hotel loading dock with a ~4 to 12 hour turnaround on the dirty-to-clean cycle. The route logistics envelope drives the despatch staging zone HVAC parameters (cool conditioned, low dust, easy access).

SBKJ supplies the hotel linen plant ductwork on the same SBAL-V, SBSF-1525, SB-ZF1500, SBFB-1500 and SBPC1500 portfolio with attention to the folding zone humidity control and the route despatch staging.

Workwear and uniform rental — Bisley KingGee Hard Yakka Stubbies Workscene

Workwear and uniform rental serves three broad segments: corporate workwear (food service, retail, healthcare non-clinical), industrial workwear (manufacturing, warehouse, construction, mining surface) and FR Fire Retardant workwear (mining underground, oil and gas, petrochemical, electrical utilities). The dominant fabric brands are Bisley Workwear, KingGee, Hard Yakka, Stubbies, Workscene and the Wells Fargo / Workrite FR specialty range. Hi-Vis (high-visibility) fabric runs across all three with retroreflective tape, fluorescent yellow / orange dye and the AS/NZS 4602 day-and-night visibility specification. FR Fire Retardant fabric runs Nomex aramid, modacrylic blend, treated cotton and the various branded analogues (Westex, Tencate, DuPont) under AS/NZS 4824 arc-flash protection and AS/NZS 4836 fire-fighting clothing.

The HVAC implications of the workwear and uniform rental segment are:

• Separate FR fabric handling zone: FR coating chemistry on treated cotton is degraded by contact with general detergent or by inadvertent contact with non-FR garments during wash and finish. Best practice is a separate climate-controlled FR zone with its own dedicated wash bank, finishing line, folding station and inspection bench. The HVAC plant feeds clean conditioned air to the FR zone with low dust loading (FR fibre sheds differently from cotton and any contamination is a contract issue).
• Inspection and repair workflow: rental workwear is inspected for damage at every return cycle and repaired (button replacement, seam re-sewing, hi-vis tape replacement, FR patch repair) or replaced (when damage exceeds repair threshold). The repair zone is a quiet, well-lit, controlled-humidity environment with low dust, separate exhaust on the repair bench, and integration with the RFID inventory system.
• RFID and barcode integration: the rental fleet is tagged for traceability through wash cycles, repairs and customer assignment. The folding line and packaging line integrate RFID readers and barcode scanners; the HVAC plant maintains stable temperature and humidity for the electronics.
• Chemical resistance on the FR coating exhaust: certain FR treatment chemistries (phosphate, halogenated, treated cotton) release trace volatile species during high-temperature finishing. 316L stainless on the FR finishing line exhaust is the SBKJ specification standard.
• Static control: Hi-Vis fluorescent dye and FR coating chemistry can be static-prone in low-humidity conditions. Folding zone humidity at 50 to 65 percent RH avoids the static issue.

SBKJ supplies the workwear and uniform rental plant ductwork on the SBAL-V, SBSF-1525, SB-ZF1500, SBFB-1500 and SBPC1500 portfolio with separate stainless construction on the FR fabric zone and the repair bench exhaust.

Dry cleaning — KSU Cleaners Express Crystal Clean Suit Yourself Press Express

The Australian dry cleaning industry runs across multi-shop chains (KSU Drycleaners, Cleaners Express, Crystal Clean, Suit Yourself, Press Express) and single-shop independents at perhaps 1,500 to 2,500 operating sites across the metropolitan and regional networks. The dominant business is suit, shirt, formal wear, wedding dress, evening wear, wool and silk garment cleaning that the conventional washer-extractor laundry cannot handle. Margins are tight, capital is light and the workforce is small (typically 2 to 6 staff per shop).

The HVAC implications were largely covered under the Perc phasing section above. Summarising:

• Perc legacy machines: AS/NZS 60079 Zone 1 on the immediate envelope, 316L stainless welded vent stack on the SBKJ SB-ZF1500 stitchwelder with closed-loop fifth-generation solvent recovery, continuous Perc vapour monitoring, and discharge clear of any intake.
• Isoparaffin (DF2000, GreenEarth, Shell Sol) replacement machines: AS/NZS 60079 Zone 1 on the immediate envelope (the chemistry is flammable), spark-resistant aluminium or non-sparking bronze fittings, 316L stainless welded vent stack on the SB-ZF1500, continuous vapour monitoring with PID calibrated to the specific isoparaffin.
• Liquid CO2 transcritical machines: no Zone classification (no flammable solvent), oxygen-deficiency monitor at breathing height, conventional 316L stainless or galvanised ductwork on the SBAL-V auto duct line and SBSF-1525 flanging.
• Professional wet cleaning machines: no Zone classification, conventional washer-extractor exhaust on the SBAL-V auto duct line plus 316L stainless on the tunnel finisher and press.
• Spot and stain treatment bench: the spot bench uses a variety of stain-treatment solvents (acetone 250 ppm WES, IPA isopropyl alcohol 400 ppm, MEK methyl ethyl ketone 200 ppm, ethyl acetate 200 ppm, MIBK methyl isobutyl ketone 50 ppm, methanol 200 ppm, polyethylene glycol and propylene glycol carrier solvents) plus the enzyme spot treatments (protease, amylase, lipase). Local exhaust ventilation at the bench in 316L stainless duct, formaldehyde monitoring if any keratin or permanent-press treatment is being run (formaldehyde 1 ppm STEL, IARC Group 1 carcinogen and being phased), and PPE backup per AS/NZS 1716.

SBKJ supplies dry cleaning shop ductwork on the SBAL-V, SBSF-1525, SB-ZF1500, SBFB-1500 and SBPC1500 portfolio with attention to the swap-out compatibility of the duct shell for the Perc-to-isoparaffin-to-CO2 transition that the operator is most likely facing over the asset life.

The chemical inventory and Safe Work Australia workplace exposure standards

The full chemical inventory in an Australian industrial laundry and dry cleaning facility, with the relevant Safe Work Australia workplace exposure standards (WES) at 8-hour time-weighted average (TWA) and short-term exposure limit (STEL) where published:

Dry cleaning solvents

• Tetrachloroethylene (perchloroethylene, Perc, PCE): 25 ppm TWA, 100 ppm STEL. IARC Group 2A. Liver, kidney, CNS and pregnancy hazard. Being phased out across Australia, EU and US. The killer.
• Isoparaffin hydrocarbon (DF2000, GreenEarth D5, Shell Sol K, Exxsol DSP): 200 ppm. Flammable. AS/NZS 60079 Zone 1 on the immediate envelope. The replacement.
• Trichloroethylene (TCE): 50 ppm STEL. IARC Group 1 carcinogen. Banned for most uses in Australia from 2023. Legacy degrease and uniform laundry only.
• Dichloromethane (DCM, methylene chloride): 50 ppm STEL. Banned for most uses in Australia from 2023. Legacy paint stripper only.
• 1,1,1-Trichloroethane: historic phased ozone-depleting substance (ODS), no longer in use.

Refrigeration and energy-storage species

• CFC R11, R12: ODS, Montreal Protocol phased, legacy only.
• HCFC R22, R141b: ODS, phased, legacy only.
• HFC R134a: phasing under the Australian HFC phase-down schedule and the Kigali Amendment.
• HFO R-1233zd, R-1234ze: low-GWP replacement, current acceptable choice for new plant.
• R32: moderate-GWP HFC, common in mid-size split and packaged units.
• R454B: low-GWP HFO blend, emerging in commercial.
• R744 (CO2): transcritical CO2, used in dry cleaning machines and in cold-storage refrigeration. Oxygen-deficiency monitoring required.
• R717 (NH3, ammonia): 25 ppm STEL. Rare in laundry but used in some cold-storage and FOG cold trap applications.

Combustion species

• CO (carbon monoxide): 30 ppm STEL. Steam boiler, LPG and natural gas burner, propane heater. Continuous monitoring in the burner room with audible alarm.
• CO2 (carbon dioxide): 5,000 ppm. Combustion product and refrigeration crossover.
• CH4 (methane): 1.25 percent LEL alarm. LPG, natural gas and propane heater. Continuous LEL monitor on any gas supply.
• NOx (nitrogen oxides): 5 ppm STEL on NO2. Combustion exhaust.

Sanitation and disinfectant species

• Cl2 (chlorine): 0.5 ppm STEL. Sodium hypochlorite bleach and chlorine-release tablet. Continuous monitor in the chemical dosing room and at the bleach point-of-use.
• Peracetic acid (CH3CO3H): 0.4 ppm STEL. Hospital and food-service linen disinfection. Continuous monitor in the chemical dosing room and at the disinfection point-of-use.
• Chlorine dioxide (ClO2): 0.1 ppm STEL. Specialty disinfection.
• Ozone (O3): 0.1 ppm STEL. UV+ozone laundry treatment, Sterrad sterilisation cycle.

Preservative and finishing species

• Formaldehyde (HCHO): 1 ppm STEL. IARC Group 1 carcinogen. Permanent-press resin finishing, Brazilian keratin treatment legacy, uniform finishing. Being phased.
• Polyethylene glycol (PEG), propylene glycol (PG): spot solvent and carrier, no specific WES but managed under general dust and aerosol limits.
• Methanol: 200 ppm. Cheap solvent, contamination risk.
• Acetone: 250 ppm. Spot solvent.
• Isopropyl alcohol (IPA): 400 ppm. Spot solvent.
• Methyl ethyl ketone (MEK): 200 ppm. Spot solvent.
• Ethyl acetate: 200 ppm. Spot solvent.
• Methyl isobutyl ketone (MIBK): 50 ppm. Spot solvent.

Particulate and biological

• Respirable dust: 5 mg/m3 TWA. Cotton, polyester, wool, microfibre, lint.
• Inhalable dust: 10 mg/m3 TWA.
• Detergent enzyme aerosol (protease, amylase, lipase, cellulase): no specific WES, controlled to lowest reasonably achievable.
• Microbial bioaerosol (hospital lane): MRSA, VRE, C. difficile, hepatitis, HIV, Brucella, Salmonella, E. coli, zoonotic agents. Controlled by the AS/NZS 4187 + ASHRAE 170 negative-pressure single-pass HEPA exhaust strategy described above.

SBKJ designs the ductwork shell, the local exhaust ventilation hoods, the chemical room exhaust, the lint baghouse interfaces and the burner room flue with all of the above WES limits and the engineered control strategy in mind. The BMS continuous monitoring on the gas vapour species (Perc, isoparaffin, CO, CH4, peracetic, chlorine, ozone, formaldehyde) is integrated with the duct system at the design stage.

Steam boiler, hot water, heat exchange and the laundry energy infrastructure

An industrial laundry runs on steam. The washer-extractor heats wash water from town-water inlet (typically 12 to 20 degrees Celsius) to the 70 to 95 degrees Celsius hot wash via steam injection or steam-heated jacket. The tumble dryer heats the air stream via gas combustion, electric resistance or steam-heated coil. The steam tunnel finisher heats and steam-injects the finishing chamber. The Calandra ironer roller is heated by saturated steam at 12 to 16 bar (or thermal oil on the higher-temperature models). The press station is steam-heated. The entire process train sits downstream of a centralised steam boiler plant.

The steam boiler plant on a typical Australian industrial laundry is:

• Boiler type: fire-tube or water-tube package boiler, gas-fired (natural gas reticulated where available, LPG bulk-tank where reticulated gas is not available), output 1 to 10 megawatt-thermal depending on plant size. Electric backup on smaller plants or as N+1 redundancy.
• Pressure: 8 to 16 bar saturated steam typical, regulated down at point of use.
• Regulation: AS 4036 / AS 4037 pressure vessel regulation, plus state-specific boiler operator certification (NSW WorkCover, VIC WorkSafe, QLD Workplace Health and Safety, WA Department of Energy Mines Industry Regulation and Safety, SA SafeWork, TAS WorkSafe, ACT WorkSafe, NT WorkSafe). The boiler operator is licensed.
• Combustion safety: burner management system (BMS, in the combustion-control sense distinct from the building BMS), flame failure detection, gas leak monitoring (CH4 1.25 percent LEL), CO monitoring downstream, NOx limit per state EPA, and emergency shutdown integration with the building fire and emergency systems.
• Combustion exhaust: stainless steel or refractory-lined flue from the boiler through the building envelope to a rooftop stack. The flue is a separate construction from the HVAC ductwork — it sits under the gas safety act and the pressure vessel act, not the AS 4254 / AS 1668.2 mechanical ventilation framework — but the HVAC engineer coordinates with the boiler installer on the flue routing, the rooftop discharge location and the combustion-air supply to the burner room.
• Heat recovery: high-efficiency plants run condensate return from the wash and finish steam lines back to the boiler feedwater tank, flash steam recovery, blowdown heat recovery and waste-heat boiler on the tumble dryer exhaust. The heat recovery economiser sits in the boiler combustion exhaust path. ISO 50001 energy management certification is the industry benchmark for the multi-site operators.
• Condensate return: the condensate from the wash and finish steam-using equipment runs back to the boiler feedwater tank via a condensate return system. The HVAC role is in the boiler room ventilation (the condensate tank vents steam, and the boiler room temperature can climb to 35 to 45 degrees Celsius without dedicated ventilation; AS 1668.2 specifies the minimum ventilation rate).
• Hot water: a parallel hot-water generation plant (heat exchanger off the steam main, or independent gas-fired water heater) supplies the lower-temperature wash circuits, the amenities and the cleaning water. The hot-water tank sits in the boiler room or in a dedicated plant room.

SBKJ supplies the boiler-room ventilation ductwork on the SBAL-V auto duct line in galvanised G90, the burner-air supply ductwork in galvanised, and the combustion-air intake hood. The combustion exhaust flue (the stack from the boiler to atmosphere) is supplied separately by the boiler vendor or by a specialist refractory contractor.

Folding, packaging, route despatch and the linen logistics backbone

Once the linen, workwear or uniform is washed, dried and finished, it has to be folded, sorted, packaged and dispatched. The folding line on a modern industrial laundry runs at 1,500 to 4,000 pieces per hour with semi-automatic feeders, automatic folders (Kannegiesser, Jensen, Lavatec and Pellerin Milnor all market folder lines) and integrated RFID and barcode tagging. Sheridan, Canningvale, Bambury, Logan and Mason and Royal Doulton linen brands are sorted, counted and packed according to the customer contract. Hotel linen is packed into customer-branded wrapping or sealed bags for delivery. Hospital linen is packed into sealed bags labelled for the specific ward or theatre. Workwear and uniform rental is packed into customer-specific bags labelled with the wearer's RFID-tagged garment ID.

The HVAC parameters across the folding and packaging zone are:

• Pressure: +5 to +10 Pa positive to the surrounding plant. Clean conditioned air drifts into the folding zone, not out of it.
• Air change rate: 6 to 12 ACH supply with MERV 13 minimum (HEPA H13 in the hospital lane).
• Temperature: 20 to 24 degrees Celsius. Workforce comfort drives the bottom of the band; fabric handling drives the top.
• Humidity: 50 to 65 percent RH. Avoids static cling on synthetic fabric, maintains cotton hand-feel, avoids worker complaints.
• Dust: below the 5 mg/m3 respirable / 10 mg/m3 inhalable WES. Low-velocity canopy hoods over the folder and packaging machines feed into the spiral conveying duct on the SBKJ SBFB-1500 spiral former.
• Noise: NC-50 maximum at the working position. Acoustic lining on supply ducts and attenuator banks on the supply trunk where the noise level is high.

The route despatch staging zone sits between folding and the loading dock. Hospital linen is cold-chain managed (12 to 18 degrees Celsius staging) to inhibit microbial growth between fold and delivery. Hotel linen is conventionally air-conditioned but cooler than the folding zone (18 to 20 degrees Celsius). Workwear and uniform is held at folding-zone conditions.

SBKJ supplies the folding and packaging zone ductwork on the SBAL-V auto duct line in galvanised G90 or stainless depending on the hospital overlay, the spiral lint conveying on the SBFB-1500, and the route despatch refrigerated ductwork where applicable.

FOG fats oils greases trap and the trade waste interface

FOG (fats, oils and greases) trap is the trade-waste interception device that removes animal and vegetable fats from a commercial waste stream before discharge to sewer, governed in Australia by AS 5664 and the trade-waste permit issued by the local water authority (Sydney Water, Yarra Valley Water, South East Water, Urban Utilities Brisbane, Water Corporation Perth, SA Water, TasWater, Power and Water NT, Icon Water ACT). Laundry plants that are co-located with a commercial kitchen — hospital catering, hotel kitchen, aged care kitchen, FIFO camp kitchen — share a FOG trap interface with the kitchen.

The HVAC role at the FOG trap and trade waste interface:

• Cold FOG trap room: some operators refrigerate the FOG trap to 4 to 10 degrees Celsius to inhibit grease softening and odour development. The refrigeration plant draws on the same chilled-water or DX refrigeration infrastructure as the cold-chain linen staging. R744 (CO2) or R454B refrigerant.
• FOG trap room exhaust: -5 to -10 Pa negative to the surrounding plant, 6 to 12 ACH single-pass exhaust through carbon filtration to atmospheric discharge. 316L stainless duct on the SBKJ SB-ZF1500 stitchwelder for the welded sections (the FOG environment is corrosive); galvanised on the bulk trunk.
• Trade waste pumping station: the laundry discharge before sewer is pumped through a screening, pH correction, BOD / COD attenuation and surfactant interception stage. Some sites add a peracetic disinfection step before discharge where the contract requires (hospital linen waste, food processing co-location). The pumping station room has its own ventilation requirement and a hydrogen sulphide (H2S) monitor where biological breakdown is likely.
• NSW EPA POEO licensing: the discharge under the Protection of the Environment Operations Act NSW (and equivalent in other states) requires the laundry to monitor pH, BOD, COD, total suspended solids (TSS), total dissolved solids (TDS), total Kjeldahl nitrogen (TKN), phosphate and surfactant load in the discharge.

SBKJ supplies the FOG trap room ductwork on the SBSF-1525 and SB-ZF1500 portfolio in 316L stainless for the chemical-exposure sections.

Facilities plant room, maintenance and the laundry as a building

The facilities plant room of an industrial laundry consolidates the steam boiler, the hot water, the compressed air, the chilled water (for cold-chain staging and for FOG refrigeration), the vacuum (for textile dust and for press station vacuum tables), the electrical switchroom and the building automation BMS. AS/NZS 5149 and AS/NZS 1677 cover the mechanical refrigeration aspects. AS 4036 / AS 4037 cover the pressure vessels. AS 3000 covers the electrical installation. The HVAC role is to maintain plant-room temperature within the equipment operating envelope (typically 5 to 40 degrees Celsius ambient with low humidity in the electrical switchroom and the BMS room), to vent any combustion or process gas to outdoor, and to maintain the air change rate per AS 1668.2 minimum.

The maintenance workflow on a multi-site industrial laundry runs to a structured schedule: daily inspection of dryer lint traps, weekly cleaning of HVAC supply diffuser faces, monthly cleaning of return grilles and lint baghouse bags, quarterly HEPA integrity test on the hospital lane single-pass exhaust, six-monthly chemical room exhaust verification with calibration of the Perc, isoparaffin, CO, CH4, peracetic and chlorine gas vapour monitors, and annual leakage test on the dry cleaning solvent vent stack with NFPA 660 baghouse deflagration vent verification on the lint side.

QC, final inspection, damaged repair and fleet replacement

The QC and final inspection zone is the last station before route despatch. Every folded and packed linen, uniform and workwear item is inspected for damage, staining, residual soil, missing buttons and broken seams. Damaged inventory is routed to the repair bench (button replacement, seam re-sewing, hi-vis tape replacement, FR patch) or to fleet replacement (where damage exceeds repair threshold). RFID and barcode integration tracks the asset through its life cycle. Accounting and contract management integrates with the customer billing and replacement-allowance terms.

The HVAC parameters across the QC zone are similar to folding and packaging — 20 to 24 degrees Celsius, 50 to 65 percent RH, 6 to 12 ACH MERV 13, low dust, NC-50 maximum. The repair bench has a local exhaust on the FR patch work and the chemical solvent stations.

Australian industry bodies, peak organisations and standards committees

The Australian industrial laundry, linen hire, dry cleaning, hospital sterile linen and workwear segments are organised through:

• Australian Industrial Laundry Council (AILC): the peak body for the multi-site industrial laundry operators (Spotless, Alsco, Initial, Aramark and the regional independents). Industry standards, best-practice guidance, sustainability and energy efficiency benchmarking.
• Drycleaners Institute of Australia (DIA): the peak body for the dry cleaning sector. Perc phasing guidance, solvent transition planning, machine-supplier liaison, workforce training and Australian solvent regulation.
• Cleaning and Linen Industry Council (CLIC): umbrella body covering the broader cleaning and linen industry, including washroom services, mat and floor care and linen rental.
• ISSA (International Sanitary Supply Association): international peak body with Australian chapter covering the sanitary supply, washroom and linen segments.
• Australian Healthcare and Hospitals Association (AHHA): peak body for the hospital sector and the AHFG framework that drives the hospital sterile linen lane specification.
• Hospital Engineers Association of Australia: the engineering body that publishes the technical guidance on healthcare facility engineering, including the sterile linen and CSSD adjacent processing.
• Standards Australia Committees: the technical committees that develop and maintain AS 1668.2, AS 4254, AS/NZS 60079, AS 1940, AS 3957, AS/NZS 4187, AS 4036, AS 4037 and the various other standards cited above.
• FSANZ (Food Standards Australia New Zealand): for the food cross-over scope (hospital catering, hotel kitchen, FIFO camp kitchen co-located with laundry).
• NSC (National Safety Council of Australia): workforce safety, dust hazard, chemical handling and the broader OHS framework.
• ICA (Internal Linen Council, the body coordinating between linen suppliers and end-users): contract terms, quality standards and benchmarking.

Certification frameworks that the multi-site operators run to:

• ISO 9001: quality management. The baseline.
• ISO 14001: environmental management. Trade waste, energy, chemical handling.
• ISO 45001: occupational health and safety. WES compliance, chemical exposure control, dust hazard.
• ISO 50001: energy management. Steam boiler efficiency, heat recovery, ISO 50001 audit and certification.
• NSQHS: National Safety and Quality Health Service Standards. The hospital-segment compliance framework for sites serving hospital linen.
• Halal: for halal-certified linen and workwear contracts.
• Kosher: for kosher-certified contracts (smaller market).
• Organic and Cradle-to-Cradle: sustainability certification for the higher-end hotel and corporate contracts.

SBKJ machine portfolio for industrial laundry HVAC duct — SBAL-V SBAL-III SBSF-1525 SB-ZF1500 SBFB-1500 SBPC1500 SBLR-600 SBTF-1500/1602/2020

The SBKJ portfolio that supplies the Australian industrial laundry, linen hire, hotel and hospital linen, workwear and uniform rental and dry cleaning HVAC duct market:

• SBAL-V auto duct line: the flagship. 0.5 to 1.5 millimetre coil thickness, 16 metres per minute working speed, 87 kilowatt installed power, coil widths up to 1,500 millimetres, configurable for galvanised G90 or Type 304 / 316L stainless steel coil with full mill certificate traceability. Produces the bulk supply, return and process-floor rectangular ductwork.
• SBAL-III auto duct line: the lighter-gauge companion for amenities, office, locker room and corridor ductwork.
• SBSF-1525 round tube flanging machine: 2.5 kilowatt, 520 kilogram, footprint 2,200 by 1,100 by 1,240 millimetre. Produces the flanged transverse joints on round duct including the fire-rated 250C / 2 hour construction on tumble dryer, steam tunnel finisher, Calandra ironer and dry cleaning solvent vent connections.
• SB-ZF1500 automatic stitchwelder: 0.8 to 3 millimetre, 100 to 1,500 millimetre length, diameter 150 to 1,500 millimetre. The critical machine for the 316L stainless welded duct on steam tunnel finisher exhaust, Calandra ironer extract, dry cleaning solvent recovery vent, chemical dosing room exhaust, hospital sterile linen chemical sterilant exhaust and FOG trap room exhaust.
• SBFB-1500 spiral former: 7.5 kilowatt, 1.20 metres per minute. Produces the round spiral lint and microfibre dust conveying duct from dryer lint trap, ironer roll exit and folding line source-capture hoods to the central cyclone and baghouse per NFPA 660 compliant construction.
• SBPC1500 plasma cutter: cuts holes, access panels, inspection ports and HEPA filter housing cutouts in stainless duct sections.
• SBLR-600 / SBLR-600A series longitudinal welders: TIG-welds the longitudinal seams on welded stainless duct sections including the dry cleaning solvent vent stack, the Calandra ironer exhaust and the hospital sterile linen chemical sterilant exhaust.
• SBTF-1500 / 1602 / 2020 series TIG and friction welders: finishing welds on the high-integrity welded stainless ductwork, particularly on the AS/NZS 4187 sterile linen and CSSD adjacent exhaust trunks where SMACNA Seal Class A integrity is verified by leak test.

Material specifications:

• Galvanised G90 (Z275): 1.5 to 3.0 millimetre, ASTM A653 equivalent. SBAL-V and SBAL-III bulk supply and return. AS 4254 Class A and B.
• Type 304 stainless steel: 1.0 to 2.0 millimetre. SBAL-V moisture-loaded supply branches into washer-extractor zones, folding zones; tumble dryer exhaust where benign chemical environment.
• Type 316L stainless steel: 1.5 millimetre minimum. SB-ZF1500 stitchwelded sections, SBFB-1500 spiral former where chemical or hospital overlay applies, SBSF-1525 fire-rated connections, SBLR-600 longitudinal welded sections. The steam tunnel finisher, Calandra ironer, dry cleaning solvent vent, chemical dosing exhaust, hospital sterile linen lane, chemical sterilant exhaust and FOG trap exhaust all run in 316L.
• Spark-resistant aluminium / non-sparking bronze: AS/NZS 60079 Zone 1 dry cleaning machine envelope, immediate solvent vapour zone.

Construction class:

• AS 4254 Class A (500 Pa): amenities, locker room, office, corridor general supply on SBAL-III.
• AS 4254 Class B (750 Pa): bulk supply and return through wash, dry and finishing process floor; hospital sterile linen clean side; steam boiler combustion air; FOG trap exhaust. SBAL-V.
• AS 4254 Class C (1,500 Pa): dry cleaning solvent vent stack, chemical sterilant exhaust, soil receiving and infectious linen single-pass HEPA exhaust, cotton lint baghouse conveying duct, steam boiler combustion exhaust flue. SB-ZF1500, SBFB-1500, SBLR-600, SBSF-1525.
• SMACNA Seal Class A: throughout the chemical-vapour, solvent-vapour, infectious-lane and hospital sterile envelopes.

Commissioning and handover — the binder that survives the asset life

The final commissioning binder for a properly designed and fabricated Australian industrial laundry HVAC duct package comprises:

• SMACNA and AS 4254 leakage test reports per zone.
• Pressure relationship test logs across the cascade (clean linen positive, soil receiving negative, dry cleaning machine envelope neutral to slightly negative, chemical dosing room negative).
• ACH verification logs at every diffuser and grille.
• HEPA integrity certificates per filter on the hospital lane single-pass exhaust and the chemical room discharge per IEST-RP-CC034.
• AS/NZS 60079 Zone 1 verification on the dry cleaning machine envelope, with solvent vapour reading at design conditions (Perc PID, isoparaffin PID).
• NFPA 660 baghouse deflagration vent verification.
• NFPA 86 tumble dryer and steam tunnel finisher combustion safety verification (where gas-fired).
• AS/NZS 4187 sterile linen pressure cascade verification on the hospital lane.
• FSANZ food cross-over inspection where applicable.
• BMS point list with alarm verification for: pressure differential, temperature, humidity, gas vapour (Perc, isoparaffin, CO, CH4, peracetic, chlorine, ozone, formaldehyde), oxygen deficiency (CO2 transcritical machine room), filter differential pressure, fan status, damper position.
• Gas vapour monitor calibration certificates.
• Boiler-room combustion safety verification and gas leak monitoring calibration.
• Trade waste discharge sampling baseline.
• ISO 9001, ISO 14001, ISO 45001 and ISO 50001 documentation alignment for the multi-site operator.
• For the hospital segment: NSQHS clinical quality file integration and AS/NZS 4187 verification.
• For the FIFO modular variant: shipping-container envelope sealing verification, off-grid power redundancy verification, dust-rated intake pre-filter staging, double-skin acoustic verification at the camp boundary, water-recycling FOG trap interface and 5 to 10 year remote-asset maintenance schedule.

The binder is the basis of every future ARBS compliance audit, AILC industry audit, DIA dry cleaning inspection, NSQHS hospital accreditation cycle, EPA POEO discharge audit and the operator's ISO certification surveillance audits. SBKJ engineering supports the commissioning team with as-built duct route drawings, machine-specific welded section certificates and material mill certificates for every stainless and galvanised section.

SBKJ at ARBS 2026 Sydney May — Box Hill North Victoria engineering

SBKJ Group exhibits at ARBS 2026 in Sydney in May, presenting the SBAL-V, SBAL-III, SBSF-1525, SB-ZF1500, SBFB-1500, SBPC1500, SBLR-600 and SBTF series machinery portfolio to the Australian refrigeration and air-conditioning industry. The SBKJ engineering team is based in Box Hill North Victoria and works with mechanical consultants, multi-site facility operators and FIFO camp builders on Australian industrial laundry, linen hire, hotel and hospital linen, workwear and uniform rental and dry cleaning HVAC duct fabrication. Standards alignment: AS 1668.2, AS 4254, AS/NZS 60079-10-1, AS 1940, AS 3957, AS/NZS 4187, NFPA 660, NFPA 86, NFPA 30, FSANZ 4.2.1 and 4.2.2, ASHRAE 170, ISO 9001, ISO 14001, ISO 45001, ISO 50001. The 12-hour engineer reply commitment applies to every spec query.

Contact SBKJ engineering

Got a spec question on industrial laundry, linen hire, hotel or hospital linen, workwear and uniform rental, dry cleaning, FIFO mine-site modular laundry or hospital sterile linen ductwork? An SBKJ mechanical engineer in Box Hill North Victoria replies within 12 hours — not a salesperson.

• Email: sales@sbkjduct.com
• Phone: +61 435 074 994
• Web: sbkjduct.com
• Office: Box Hill North, Victoria, Australia
• Show: ARBS 2026, Sydney, May 2026