Mattress, Bedding, Pillow, Quilt, Bedhead, Furniture Foam, Memory Foam and Latex Foam Manufacturing HVAC Duct Engineering Guide

1. Why mattress, bedding and foam ductwork is different from general manufacturing

An Australian mattress, bedding, pillow, quilt, bedhead, furniture foam, memory foam or latex foam manufacturing facility sits at one of the most demanding intersections in industrial HVAC engineering — a combustible polymer dust deflagration risk, an isocyanate respiratory sensitisation risk that begins at parts-per-billion, ammonia exposure at latex moulding lines, fibre and lint dust that ignites at minimum ignition energy below 30 millijoules, a finished product whose flammability is regulated under consumer-safety standards, and an end-to-end process that runs from a tanker of methylene diphenyl diisocyanate or a 60 percent rubber latex concentrate at the inlet to a soft retail bedding product at the outlet. We see clients regularly walk into a duct quotation expecting numbers from a generic manufacturing plant or a cabinetmaker, and the engineering reality is closer to a fine-chemical plant in some duct sections than to a furniture factory.

The dust load is unlike anything outside a sawmill or a flour mill. A modern polyurethane foam factory making slabstock for mattress core production processes 50 to 250 tonnes of foam per week through cutting, shaping, contour profiling and quilting operations, generating 0.8 to 2.5 percent of input mass as foam dust, lint and offcut fines — between 400 kilograms and 6 tonnes of combustible foam dust per week feeding the dust extraction circuit. The fines fraction at the CNC contour cutter is dominated by sub-200 micron foam particles with minimum ignition energy below 30 millijoules.

The chemical load includes bulk methylene diphenyl diisocyanate (MDI) or toluene diisocyanate (TDI) as the hardener side of the foam reaction, bulk polyol as the resin side, tin and amine catalysts, surfactant, water as the blowing agent, and flame retardant additives. The Safe Work Australia workplace exposure standard for TDI is 0.005 ppm STEL — fifty times tighter than the more common solvent STELs — and there is no known safe respiratory exposure level. A latex plant substitutes natural rubber latex concentrate at 60 percent solids stabilised with 0.7 to 1.4 percent ammonia, plus zinc oxide, sulphur, accelerator and antioxidant packages. Ammonia is the dominant operator exposure with a Safe Work Australia STEL of 35 ppm. The combined chemistry across one mattress and bedding factory exceeds what most furniture factories handle.

An Australian mattress and bedding plant is typically 5,000 to 30,000 square metres under one roof. Sealy Australia at Padstow NSW, A.H. Beard at Padstow NSW, Sleepmaker (Joyce Corporation), Tempur Australia at Castle Hill NSW and the broader retail-supplier ecosystem cover the volume segment. Dunlop Foams at Padstow NSW and Joyce Foam Products at Wetherill Park NSW cover the slabstock and conversion side. HVAC duct run lengths range from 30 to 60 metres at a small foam converter to 200 to 400 metres at an integrated plant, with 18 to 30 capture branches converging on two or three mid-size dust collectors at a mid-size foam conversion shop.

The regulatory frame is shifting. In 2025 the United States National Fire Protection Association consolidated NFPA 484, NFPA 654, NFPA 655 and NFPA 664 into the combined NFPA 660 standard for combustible dusts. Australia's native AS 3957 (Dust Hazard Assessment) was published in 2024 as the local equivalent of the NFPA 660 DHA process. The joint NFPA 660 / AS 3957 framework is the current compliance reference for any mattress, bedding or foam manufacturing facility SBKJ engineers in 2026. AS/NZS 4088 cigarette ignition resistance and the voluntary AS 5811 mattress flammability schemes drive the foam chemistry and additive package, which in turn drives the slabstock tunnel exhaust chemistry.

This guide is the reference our engineers use at our Box Hill North VIC office when we quote a duct package for this sector. Read alongside our Custom Joinery, Cabinetmaking and Furniture HVAC Duct Engineering Guide for the bedhead framing parallel, our Automotive Paint Booth HVAC Duct Engineering Guide for the spray finishing parallel, and our Welding Methods HVAC Duct Fabrication Guide for the stainless construction methods that underpin the isocyanate and ammonia exhaust duct.

2. The Australian regulatory framework

Fourteen standards govern HVAC ductwork in Australian mattress, bedding, pillow, quilt, bedhead, foam and latex manufacturing facilities. Four are mechanical ventilation and ductwork codes, four are combustible dust and fire codes, three are flammable liquids and spray finishing codes, two are toxic substance and hazardous area codes, and one is the consumer-product flammability code that drives substrate chemistry.

2.1 AS 1668.2 — Mechanical ventilation

AS 1668.2 is the umbrella industrial mechanical ventilation standard for Australia, setting minimum outside air per occupant for office and showroom areas, capture velocity targets for industrial process exhaust hoods, and referencing the Safe Work Australia workplace exposure standards. For mattress and foam manufacturing the capture velocity targets are 1.0 m/s at a foam contour cutter enclosure, 1.5 m/s at a hot-wire profiler face, 1.0 m/s at a quilting trim station, 1.0 m/s at a pillow filling station, and 0.5 m/s at a downdraft bedhead spray booth grating. Dilution ventilation is 6 to 10 ACH across general production, 10 to 15 ACH in the foam cutting room and quilting hall, and 15 to 25 ACH in the polyol-isocyanate day-tank room and latex mix room.

2.2 AS 4254 — Ductwork for air-handling systems

AS 4254 is the Australian ductwork fabrication standard. AS 4254.2 sets the gauge schedule for galvanized steel duct, the joint and seam standards, and the leakage classification by pressure class. For mattress and foam dust extraction the standard pressure class is Class C (medium-pressure positive 500 to 1000 Pa or negative 250 to 500 Pa at suction side of fan). Isocyanate and ammonia exhaust ductwork is also Class C with stainless construction. AS 4254.2 conformity is the SBKJ default for every duct package.

2.3 AS 1530.3 — Flammability of materials

AS 1530.3 covers ignitability, flame propagation, heat release and smoke index of duct lining and insulation. Mattress and bedding manufacturing facilities are BCA Class 8 industrial occupancy, with duct lining required to meet Group 1 or Group 2 fire classification under AS 5637. The SBKJ default is Group 1 ductwrap and ductliner on every fire-rated duct run and on supply and return ductwork through occupied production volume, adding approximately 8 to 12 percent to the lining cost while reducing smoke yield in any unintended duct fire.

2.4 AS 3957 — Dust hazard assessment

AS 3957 was published in 2024 as the Australian equivalent of the NFPA 660 DHA requirement. Every facility processing combustible dust above the threshold quantity (around 12 kilograms per shift, easily exceeded in any production foam cutting or quilting operation) must complete a documented DHA covering ignition sources, dust accumulation locations, engineered controls and residual risk register. The DHA is refreshed every 5 years and re-issued at any process change. The DHA findings drive the bonding scheme, the spark detection, the explosion vent sizing and the isolation valve specification.

2.5 NFPA 660 — Combustible particulate solids (formerly NFPA 484, 654, 655, 664)

In 2025 the NFPA consolidated four prior standards into the combined NFPA 660. The pre-2025 NFPA 654 (combustible particulate solids) — the principal reference for polyurethane foam dust, polyester fibre lint, latex foam dust and pillow filling lint — is now folded into NFPA 660. Australian insurers, fire engineers and operator safety teams reference NFPA 660 as the current global benchmark. Headlines: settled foam, fibre and lint dust deeper than 1.6 mm anywhere in the facility is a housekeeping failure requiring immediate correction, dust collectors must have deflagration vents sized to NFPA 68, isolation valves between machinery and the dust collector are mandatory, and continuous dust deposition monitoring is required under any insurer's policy.

2.6 NFPA 68 — Explosion venting

NFPA 68 sets the design rules for deflagration venting — vent panels that direct an in-progress dust explosion to a safe area outside the building. Kst values: polyurethane foam dust 110 to 180 bar·m/s, polyester fibre lint 100 to 150, latex foam dust 130 to 200, mixed quilting fibre and feather lint 80 to 130. Dust collector vent panels for a typical foam plant cyclone-plus-bag-filter combination are 1.5 to 4.0 square metres aggregate vent area. SBKJ supplies the duct package with vent panel mounting flanges welded in at the factory.

2.7 NFPA 69 — Explosion prevention

NFPA 69 covers explosion prevention where venting is not feasible — dust collectors located within a building envelope without external wall access. Options include inertion, oxidant concentration reduction, deflagration suppression (sodium bicarbonate or monoammonium phosphate discharged within milliseconds of detection) and pressure containment. Mattress and foam applications typically use chemical suppression where venting is impractical, with the suppression supplier coordinating to the SBKJ-supplied isolation valve flange.

2.8 AS/NZS 60079 — Hazardous areas

AS/NZS 60079.10.2 classifies areas with combustible dust: Zone 20 (continuous — interior of dust collectors and cyclone discharge), Zone 21 (likely in normal operation — around access doors and explosion vent discharges), Zone 22 (unlikely but may occur — interior of every closed dust extraction duct). AS/NZS 60079.10.1 covers flammable vapour: Zone 2 around polyol and isocyanate tanks, Zone 1 at decanting stations and inside the polyol-isocyanate mix head, Zone 1 inside the slabstock tunnel during foam rise. All electrical equipment must carry Ex e or Ex d certification, and all metal ductwork must be electrically bonded under 10 ohms to plant earth.

2.9 AS 1940 — Flammable and combustible liquids storage and handling

AS 1940 sets quantity thresholds for flammable liquid licensing, bunding and spill containment requirements, separation distances and ventilation rates for solvent storage. For a foam plant AS 1940 governs the polyol day-tank room (polyol is Class C2 combustible with flash point above 93 °C), the catalyst and surfactant store, the blowing agent store (in legacy methylene chloride or HFC formulations) and the bedhead paint mix room. Exhaust ventilation 10 ACH minimum for combustible-liquid stores, 15 ACH for flammable, low-level extract for heavier-than-air vapour.

2.10 AS 4332 — Ammonia refrigeration and storage

AS 4332 covers ammonia refrigeration plant, with its hazardous area classification principles referenced for any process releasing ammonia at hazardous concentration. Latex foam moulding releases 5 to 25 kg/day of ammonia from latex day tanks containing 0.7 to 1.4 percent stabiliser. SBKJ exhaust ductwork is designed to maintain ambient ammonia concentration below the Safe Work STEL of 35 ppm at every operator working position.

2.11 AS 4114 — Spray painting booths and rooms

AS 4114 is the Australian standard for spray booth design. Face velocity 0.5 m/s minimum for solvent-borne, 0.4 m/s for waterborne, 0.6 to 0.75 m/s for 2K polyurethane. Booth must have interlocked lights and exhaust fan, 60-minute FRL panel, spark-resistant fan per AMCA 99 Type B minimum, conductive floor or grating, and emergency manual override on the exhaust fan. SBKJ supplies the bedhead spray booth supply plenum and exhaust ductwork to AS 4114 conformity.

2.12 NFPA 33 — Spray application using flammable and combustible materials

NFPA 33 is the de facto international spray finishing standard, referenced by Australian regulators as a complement to AS 4114. Key requirements: spray booth exhaust ductwork of metal construction (aluminium and plastic prohibited), exhaust velocity sufficient to prevent solvent vapour above 25 percent of the lower explosive limit, exhaust ductwork electrically continuous and bonded, fan of spark-resistant construction. SBKJ designs to a 10 percent LEL working margin to allow for transient peaks.

2.13 AS/NZS 4088 and AS 5811 — Mattress and bedding flammability

AS/NZS 4088 covers cigarette ignition resistance for upholstered furniture and bedding. AS 5811 (voluntary) adds open-flame testing. Neither standard governs HVAC directly, but both drive the foam additive package — flame retardant chemistry, fabric treatment, barrier layer — and therefore the chemistry that reaches the duct. Modern flame retardants are phosphate-based (TCPP, TDCP) or graphite-expansion (brominated retardants largely phased out under Stockholm Convention). SBKJ specifies 304L stainless on the slabstock tunnel exhaust where flame retardant additives reach the gas phase.

2.14 BCA Section C — Fire-rated separation and duct penetrations

BCA Section C sets fire-rated separation requirements between occupancies and between production zones with different fire load. Mattress and foam facilities typically require fire-rated separation between the polyol-isocyanate plant and warehouse, between the foam cutting hall and offices, between the bedhead spray booth and assembly, and between the warehouse and adjacent tenancy. SBKJ supplies fire-rated dampers and the matching duct collars sized to the building fire engineer's drawing.

3. Process zones in an Australian mattress, bedding and foam facility

A typical Australian mattress, bedding, pillow, quilt, bedhead, furniture foam, memory foam or latex foam manufacturing facility is a sequence of process zones, each with a distinct HVAC duty. We walk through them in production order, calling out the duct duty, the material selection and the SBKJ specification.

3.1 Raw material storage — foam blocks, fibre bales, fabric rolls

The raw material warehouse holds slabstock foam blocks (typically 2.0 by 1.4 by 1.0 metre or equivalent, brought in from the slabstock plant or imported), polyester fibre and batting bales, fabric rolls for ticking and quilting, timber for bedhead substrates, and steel innerspring wire coils. Ventilation here is dilution only — air change rate 4 to 6 per hour driven by occupant thermal comfort and low-level off-gassing from the foam (residual TDI or MDI free-isocyanate emission from new slabstock at the part-per-billion level for 14 to 28 days after foaming). Galvanized G90 supply and return duct, no special considerations. Air change rate elevates to 8 to 10 ACH where freshly-foamed slabstock is held in the warehouse during the cure period.

3.2 Polyol and isocyanate day-tank room (integrated slabstock plants)

The integrated polyurethane slabstock plant receives polyol and isocyanate (typically MDI for furniture and bedding foam; TDI legacy at older lines). Day tanks 3,000 to 10,000 litres each, polyol at 20 to 30 °C, isocyanate at 25 to 30 °C with humidity-controlled headspace. The tank room is Zone 2 with localised Zone 1 at decanting, sampling and level-instrumentation access points. Ventilation 15 to 25 ACH with low-level extract (within 300 mm of the floor) for heavier-than-air vapour, high-level make-up supply. Duct material 304L stainless on general tank-room extract, 316L on the decanting local exhaust. AMCA 99 Type B spark-resistant fan with Ex e motor in the Zone 2 envelope. SBKJ specifies 1.5 mm stainless spiral, TIG-welded seams, conductive gaskets, full electrical bonding. Discharge to activated carbon scrubber and stack per facility environmental licence.

3.3 Slabstock foam tunnel — continuous production line

The slabstock tunnel is the dominant process zone in an integrated foam plant. Polyol, isocyanate, tin and amine catalysts, water, surfactant and flame retardant meter through the mix head onto a moving conveyor belt at 1 to 3 m/min. Foam rises through cream-rise-gel-cure stages over 3 to 10 minutes, peak exotherm 160 to 180 °C in the slabstock core. Tunnel exhaust handles free isocyanate, amine catalyst, blowing agent, water vapour and trace CO2.

Duct material 316L stainless because chemistry is mildly acidic, elevated temperature (60 to 110 °C in the exhaust stream), and continuous. Two to four take-off points along the tunnel (cream zone, rise zone, gelation zone, cure zone) each feeding a branch to the main exhaust manifold. SBKJ specifies 1.5 mm 316L spiral, 250 to 400 mm diameter per take-off, TIG-welded seams, insulated external to maintain wall above the dew point, electrically bonded. Discharge through thermal oxidiser or activated carbon scrubber per EPA Victoria, NSW EPA, Queensland DES or WA DWER licence limit (typically 0.5 to 2.0 mg/m3 in stack discharge).

3.4 Slabstock curing tunnel and cooling area

Post-foaming the slabstock bun cures on conveyor or roller bed through a curing tunnel for 12 to 48 hours. Curing tunnel exhaust handles residual isocyanate and amine at lower concentration than the foaming tunnel, plus blowing agent and slow thermal release. 304L stainless duct because chemistry concentration is lower and temperature 30 to 60 °C. SBKJ specifies 1.5 mm 304L spiral, 200 to 350 mm diameter per take-off, TIG-welded seams, external insulation where the tunnel passes through unconditioned space.

3.5 Latex foam moulding — Dunlop and Talalay processes

The Dunlop process whips natural rubber latex concentrate with zinc oxide, sulphur, accelerator and antioxidant, gels with sodium silicofluoride, pours into aluminium mould, vulcanises at 100 to 130 °C for 20 to 90 minutes, demoulds, washes, dries. The Talalay alternative uses vacuum-degas, flash-freeze at minus 30 °C, CO2 gelation, then heat to 100 to 130 °C for vulcanisation. Dominant exhaust duty in both is ammonia released through mixer, pour station, mould transfer, vulcanising oven and demould, plus minor SO2 and trace fluorosilicate dust.

316L stainless on every latex moulding exhaust because ammonia plus water vapour plus chloride trace is mildly aggressive to 304L over 18 to 30 months. Capture velocity 1.0 m/s at hood face, branch duct 250 to 400 mm diameter, conveying velocity 12 to 15 m/s (lower than dust extraction because contaminant is gaseous). SBKJ specifies 1.5 mm 316L spiral, TIG-welded seams, conductive gaskets, full bonding. Discharge through wet scrubber for ammonia removal — dilute sulphuric acid or citric acid packed-bed — with scrubber blow-down as Trade Waste under state water authority licence. The Talalay process adds a CO2 release exhaust at gelation and a freezer vent at flash-freeze, both 304L because chemistry is less aggressive.

3.6 Foam block cutting — horizontal and vertical block saw

The slabstock bun (2.0 by 1.4 by 1.0 metre block) is sectioned into mattress-, pillow- or bedhead-cushion-size pieces using a horizontal block saw or vertical reciprocating/band-type blade saw. Dust generation 0.5 to 2 percent of input mass as foam crumb and dust. Capture at a hood beneath and around the cutting blade at 1.5 m/s, branch duct 200 to 300 mm at 22 m/s, galvanized G90, 1.2 mm spiral, bonded.

3.7 Foam contour cutting — CNC contour cutter

The 5-axis or 7-axis CNC foam contour cutter is the dominant fine-dust source in a modern foam conversion facility. Reciprocating blade or oscillating tangential knife shapes the foam block into ergonomic profiles, generating 0.8 to 2.5 percent of input mass as fine foam dust with median particle size below 200 microns. Fines fraction reaches 40 percent of total mass at high-speed contour cutting on high-density foam.

Capture via enclosed cutting chamber at 1.5 m/s face velocity. Branch duct 250 to 400 mm at 22 m/s, galvanized G90, 1.2 mm spiral. The CNC cutter is the highest-risk ignition source in the foam conversion shop — high-speed blade frictional heat plus chipped-blade hot fragments. SBKJ specifies spark detection at the cutter branch with infrared sensor and water injection or fast-acting damper, plus isolation valve between cutter and dust collector. Three-layer NFPA 660 protection: spark detection plus isolation valve plus deflagration vent on the dust collector.

3.8 Foam profiling — hot-wire profiler

The hot-wire profiler cuts foam blocks using a heated nichrome or kanthal wire that melts through the foam. Cleaner cut than blade cutting with less crumb, but the heated wire releases pyrolysis products — isocyanate fragments, amine fragments, CO trace, HCN trace at high temperature. Capture at an enclosed extraction hood above the cutting line at 1.0 m/s. Branch duct 200 to 300 mm at 18 m/s, 304L stainless because pyrolysis products attack zinc over 18 to 24 months. SBKJ specifies 1.2 mm 304L spiral on the hot-wire profiler branch.

3.9 Foam pulverising, grinding and bonded foam

Foam offcut and trim is pulverised or ground for re-use as bonded foam carpet underlay, secondary cushion fill or insulation. Dust generation high — 5 to 15 percent of input mass as fines, heavily into the combustible range. Branch duct 250 to 400 mm at 22 m/s, galvanized G90, 1.6 mm spiral (thicker wall for abrasion resistance). Spark detection mandatory at the grinder outfeed, isolation valve, deflagration venting per NFPA 68. The bonded foam line sprays pulverised foam with MDI prepolymer binder (8 to 15 percent by weight), compresses in heated mould at 80 to 120 °C. Binder spray station is the highest-isocyanate-exposure station in the bonded foam plant — SBKJ specifies 316L stainless capture at 250 to 350 mm at 18 m/s. Bonding press exhaust is 304L.

3.10 Memory foam (viscoelastic polyurethane) — moulded and slabstock

Memory foam is a temperature-sensitive open-cell polyurethane with slow recovery. Production either as slabstock through a dedicated viscoelastic tunnel (different polyol blend, lower isocyanate index, chain extender additive) or as moulded pieces in closed aluminium moulds. Memory foam slabstock tunnel exhaust 316L stainless (same as standard PU slabstock); moulded press station 304L stainless on the mould release local exhaust.

3.11 Quilting line — multi-needle, shuttle and decorative pattern

The quilting line bonds layers of fabric ticking, foam sheet, polyester batting and insulation into a quilted assembly. Multi-needle quilters run hundreds of needles in parallel; shuttle and decorative pattern quilters run a single moving head. Dominant exhaust duty is fibre lint at needle penetration and trim, plus minor adhesive vapour. Branch duct 200 to 300 mm at 20 m/s, galvanized G90, 1.2 mm spiral, bonded. Fibre lint is combustible at typical loading — the quilting line dust collector requires deflagration venting per NFPA 68 and spark detection at the inlet.

3.12 Mattress edge tape line

The mattress edge tape line wraps the perimeter of the assembled mattress with fabric edge tape. Fibre lint at the cutting blade and binding needle, captured at an enclosed extraction hood at 1.0 m/s. Branch duct 150 to 200 mm at 18 m/s, galvanized G90, 1.2 mm spiral, bonded.

3.13 Pillow filling line — feather, fibre and foam shred

The pillow filling line fills empty pillow casings with down and feather, polyester staple fibre, polyester hollowfibre, shredded memory foam, shredded latex foam or bamboo fibre. One of the dustiest stations in the entire bedding plant — filling material is conveyed pneumatically through an open-topped filling head, with overflow escaping into the working volume. Capture at downdraft filling table at 0.5 m/s grating face velocity, branch duct 200 to 300 mm at 20 m/s, galvanized G90, 1.2 mm spiral, bonded.

Down and feather circuits carry additional fire risk — feather lint accumulates rapidly in the duct, down has very low MIE and high surface-area-to-mass ratio. SBKJ specifies elevated conveying velocity (22 m/s) on down and feather branches, with 4-week duct cleaning interval. Spark detection mandatory at the dust collector inlet.

3.14 Quilt and doona filling line

Similar to the pillow filling line at larger scale — polyester batting or down/feather blown into larger fabric envelope, channel-stitched to lock the filling. Capture at downdraft filling table at 0.5 m/s, branch duct 250 to 400 mm at 20 m/s, galvanized G90, 1.2 mm spiral, bonded. Deflagration venting per NFPA 68 and spark detection at the dust collector inlet.

3.15 Innerspring coil production and tempering oven

The innerspring core is fabricated from coiled steel wire. The coil line draws wire, forms individual springs on an automatic coiler, knots ends, assembles springs into a coil unit, and passes the assembly through a tempering oven at 200 to 300 °C to relieve stresses. The tempering oven exhaust handles thermal release, lubricant smoke from residual wire drawing lubricant and gas burner combustion products. Duct material 304L stainless because of elevated temperature (oven exhaust 150 to 250 °C) and mildly acidic combustion products. SBKJ specifies 1.5 mm 304L spiral, 300 to 500 mm diameter, TIG-welded seams, insulated external, electrically bonded. Pocket coil units (modern alternative to Bonnell coil and continuous wire) add minor fabric trim dust at pocket-forming and pocket-cutting stations — galvanized G90, 1.0 mm spiral.

3.16 Bedhead frame fabrication, foam wrap and fabric stretch

The bedhead frame is a timber substrate (plywood, MDF or LVL) cut on panel saw, CNC router or band saw — galvanized G90 dust extraction at 22 m/s conveying velocity (router/panel saw), 18 m/s (sander), full bonding, spark detection. Cross-reference our Custom Joinery, Cabinetmaking and Furniture HVAC Duct Engineering Guide for the timber-side detail. The foam wrap station bonds 25 to 75 mm foam sheet to the substrate with hot-melt or contact adhesive. Hot-melt applicator captured at 1.0 m/s, galvanized branch. Contact adhesive (solvent-based contact cement) requires 304L stainless local exhaust at 150 to 200 mm at 18 m/s. The fabric stretch station wraps decorative fabric over the foam-wrapped substrate and staples to the rear face — minor fibre lint, spot exhaust at 1.0 m/s, 100 to 150 mm at 18 m/s, galvanized G90.

3.17 Bedhead spray finishing

Premium and design-led bedhead products require clear lacquer or decorative finish on exposed timber. Small cross-draft or semi-downdraft booth 2 to 5 metres wide, 0.5 m/s face velocity, AMCA 99 Type B spark-resistant fan. 304L stainless exhaust because solvent-borne finish attacks zinc within 18 to 24 months. SBKJ specifies 1.2 mm 304L spiral on the booth exhaust, with the supply plenum in galvanized G90 1.0 mm rectangular construction.

3.18 Mattress assembly, compression packaging and warehouse

The general assembly area is conditioned at 6 to 8 ACH with galvanized G90 supply and return, plus Group 1 fibreglass acoustic lining per AS 1530.3. The compression packaging line vacuum-compresses the finished mattress to 25 percent of original volume — overhead spot exhaust at 1.0 m/s, branch 150 to 200 mm at 18 m/s, galvanized G90. The finished goods warehouse is conditioned at 18 to 24 °C and 40 to 60 percent RH year-round. Office and showroom require AS 1668.2 outside air at 10 L/s per person, AS 2107 NC-35 to NC-40, MERV 13 or HEPA supply filtration.

4. Material selection summary

The SBKJ material specification framework for an Australian mattress, bedding, pillow, quilt, bedhead, furniture foam, memory foam or latex foam manufacturing facility reduces to a decision tree by duct duty.

4.1 Galvanized G90 — the workshop dust extraction baseline

• Branches and mains for foam cutting dust extraction — CNC contour cutter, block saw, foam pulveriser and grinder, mattress edge tape line, bedhead sander.
• Branches and mains for quilting and bedding dust extraction — multi-needle quilter, shuttle quilter, decorative pattern quilter, pillow filling line, quilt and doona filling line, mattress assembly trim.
• Bedhead frame dust extraction — panel saw, CNC router, wide-belt sander for timber substrate.
• Bedhead spray booth supply plenum — both downdraft and semi-downdraft ceiling supply.
• General assembly area — supply and return HVAC, standard commercial fabrication.
• Office, showroom, customer experience centre and amenities — supply and return HVAC.
• Finished goods storage warehouse — humidity-controlled storage HVAC.
• Compression packaging line spot exhaust — hydraulic press capture.
• Innerspring assembly line minor extracts — pocket coil station, knotter station.

Wall thickness 1.0 mm minimum for branches up to 250 mm diameter, 1.2 mm minimum for branches and mains 250 to 500 mm, 1.6 mm minimum for mains above 500 mm. Coating G90 zinc minimum (275 g/m² total both faces) per AS 1397.

4.2 304L stainless steel — the solvent, isocyanate-trace and high-temperature duty

• Slabstock curing tunnel exhaust — secondary cure tunnel where chemistry concentration is reducing.
• Hot-wire foam profiler exhaust — pyrolysis-product capture.
• Bonded foam press exhaust — heated press exhaust at 304L grade.
• Memory foam moulded press station exhaust — mould release station local exhaust.
• Bedhead spray booth exhaust duct — from booth filter bank to discharge stack on solvent-borne lacquer finishes.
• Bedhead spray booth discharge stack — typically 304L for solvent-borne.
• Bedhead paint mix room exhaust — solvent storage room extract.
• Contact adhesive station local exhaust — solvent-based contact cement application.
• Innerspring tempering oven exhaust — elevated-temperature combustion product exhaust.
• Polyol day-tank room general extract — combustible liquid room extract.
• Slabstock cure room dilution exhaust — secondary cure volume above curing slabstock blocks.

Wall thickness 1.2 mm minimum for branches up to 250 mm, 1.5 mm minimum for branches and mains above 250 mm. Spiral construction per AS 4254, TIG-welded longitudinal seams where rectangular construction is required.

4.3 316L stainless steel — the high-isocyanate, ammonia and acid duty

• Polyurethane slabstock foaming tunnel exhaust — peak isocyanate and amine catalyst emission.
• Isocyanate (TDI / MDI) day-tank room local exhaust — decant station, sampling station, transfer station local capture.
• Polyol-isocyanate mix head exhaust — peak isocyanate concentration at the foam reaction initiation point.
• Bonded foam binder spray station exhaust — MDI prepolymer spray capture.
• Latex foam moulding mixer, pour station, mould transfer exhaust — Dunlop and Talalay ammonia capture.
• Latex foam vulcanising oven exhaust — ammonia plus steam plus minor sulphur dioxide.
• Latex foam demould station and wash station exhaust — residual ammonia and water vapour.
• Memory foam slabstock foaming tunnel exhaust — same chemistry as standard polyurethane slabstock at 316L grade.
• Ammonia scrubber feed duct — feed to wet scrubber for ammonia abatement.

Wall thickness 1.5 mm minimum throughout. Spiral construction per AS 4254, TIG-welded longitudinal seams where required.

4.4 Aluminium — prohibited in dust and finishing duty

Aluminium duct is prohibited in any duct conveying combustible foam, fibre, lint or feather dust under NFPA 660, and prohibited in solvent-rich bedhead spray booth exhaust under NFPA 33. The justification is spark generation under impact — a tool dropped on aluminium duct, a fragment thrown by the source equipment, or duct support hardware striking the duct can produce a spark above the minimum ignition energy of fine foam dust, feather lint or solvent vapour. SBKJ does not supply aluminium duct in mattress, bedding or foam applications.

5. Conveying velocity targets by source

Conveying velocity in mattress, bedding and foam dust extraction ductwork is set by the heaviest particle that must remain entrained at the lowest design flow rate. Sub-velocity operation causes settlement, settled dust ignites under spark, and the system propagates to deflagration. The SBKJ targets:

• CNC contour cutter mixed foam dust and offcut — 22 m/s minimum at the worst-case branch flow.
• Hot-wire profiler fine foam dust — 18 m/s minimum at the worst-case branch flow.
• Foam pulveriser and grinder — 22 m/s minimum.
• Foam block saw (horizontal and vertical) — 22 m/s minimum.
• Quilting line fibre and lint (multi-needle, shuttle, decorative) — 20 m/s minimum.
• Pillow filling line (feather, fibre, foam shred) — 20 m/s minimum; 22 m/s for down and feather circuits.
• Quilt and doona filling line — 20 m/s minimum.
• Mattress edge tape trim line — 18 m/s minimum.
• Bedhead frame sander (timber substrate) — 18 m/s minimum (wide-belt sander baseline).
• Bedhead frame panel saw and CNC router — 20 to 22 m/s minimum.
• Bedhead fabric stretch and staple station — 18 m/s minimum.
• Cyclone-to-bag-filter interconnect — 22 m/s minimum.
• Spark detection branch downstream of cutter or grinder — 22 m/s (slight margin over baseline to ensure detection reliability).

These are minimum velocities at the worst-case operating condition. SBKJ engineering specs spiral mains at peak operating flow including the load case where 70 to 80 percent of branches are open with the rest blanked off — the load case where main flow drops without changing main diameter. Designing for design-average flow guarantees settlement and combustible deposit accumulation within 12 months.

The capture velocity at the hood face is a separate target. SBKJ specifies 1.5 m/s at the face of an enclosed CNC contour cutter, 1.0 m/s at a quilting line hood, 1.0 m/s at a pillow filling table grating, 1.0 m/s at a bedhead sander hood, 1.5 m/s at an isocyanate decanting station, 1.0 m/s at a latex mix station, and 0.5 m/s at the face of a downdraft bedhead spray booth grating.

6. Hazardous area classification

Every Australian mattress, bedding, pillow, quilt, bedhead, foam and latex manufacturing facility we have surveyed has a layered hazardous area profile combining combustible dust, flammable vapour and toxic gas duty.

• Zone 22 (combustible dust) — interior of every dust extraction duct serving foam cutting, foam profiling, foam pulverising, quilting line, pillow filling, quilt and doona filling, mattress edge tape, bedhead frame sanding, and bedhead fabric stapling. Also the volume immediately around dust collector access doors and inspection hatches.
• Zone 21 (combustible dust likely) — around the dust collector access doors and inspection hatches during cleaning operations, and around bag filter explosion vent discharges during a deflagration event. Also the cyclone discharge cone interior during normal operation.
• Zone 20 (combustible dust continuous) — interior of dust collectors at all times during operation, the cyclone collection chamber, and the foam pulveriser internal volume.
• Zone 2 (flammable vapour) — polyol day-tank room (general volume), isocyanate day-tank room (general volume), slabstock tunnel volume during cure phase, bedhead paint mix room (general volume around solvent storage), and bedhead spray booth interior between cycles.
• Zone 1 (flammable vapour normal) — interior of ventilated solvent cabinets, polyol and isocyanate decanting stations, polyol-isocyanate mix head local volume, slabstock tunnel volume during foam rise and gelation, and bedhead spray booth interior during spraying.
• AS 4332 ammonia hazardous volume — latex day-tank room (general volume), latex moulding station (local volume around mixer, pour station and mould transfer), latex vulcanising oven discharge (transient), and latex demould station (local volume).

Every metal duct section in any Zone 20, 21 or 22 envelope is electrically bonded under 10 ohms to plant earth, with copper bonding strap at every flange and conductive gaskets at every access door. Non-metallic flexible connectors are prohibited inside the bonded envelope. Re-tested at commissioning, every two years thereafter, and after any modification. The bonding scheme is the cheapest single control measure in the entire compliance package and the most reliable defence against the most common ignition source (electrostatic discharge from accumulated static on an unbonded duct section).

7. Acoustic targets and lining specification

Mattress and foam manufacturing is a noisy industry. Dominant noise sources are foam cutting machinery, quilting line needle banks, pillow filling air blowers, slabstock tunnel exhaust fans, dust collector pulse-jet valves and compression packaging hydraulics. Operator exposure must meet Safe Work Australia 85 dB(A) 8-hour TWA limit, and most production zones operate at 78 to 88 dB(A) ambient noise without intervention. SBKJ specifies acoustic duct lining Group 1 fibreglass per AS 1530.3 on supply ductwork to occupied production volumes, NRC 0.85 or better at the 250 to 2000 Hz band, 25 mm thickness at supply plenums and 50 mm at fan inlet plenums. The slabstock tunnel exhaust fan and dust collector require additional inline silencer treatment — packed dissipative silencer with 25 mm acoustic absorber lining, designed for 15 to 25 dB insertion loss at the 250 to 1000 Hz band, galvanized G90 outer, perforated stainless inner.

8. Spark detection and isolation

Every foam cutting, pulverising, quilting, pillow filling and bedhead sanding circuit requires spark detection at the dust collector inlet and an isolation valve between source machinery and dust collector. NFPA 660 minimum protection — Australian insurers require it on any new installation. Spark detection sensor is an infrared sensor mounted in the duct wall, looking radially across the duct lumen for hot fragment spectral signature, with detection under 5 milliseconds. Response is water injection (typical for foam dust circuits because water does not damage downstream polyurethane or polyester dust load) or fast-acting damper closure within 50 to 100 milliseconds (typical for high-volume contour cutter circuit where water injection would risk dust collector cake degradation). Isolation valve between source machinery and dust collector is chemical-suppression-activated knife-gate damper or passive flap valve, closing within 100 milliseconds of deflagration detection downstream, preventing flame propagation back from collector into the cutting room. SBKJ supplies the duct package with welded-in isolation valve mounting flanges at the position specified by the suppression supplier.

9. Slabstock tunnel exhaust — engineering depth

The polyurethane slabstock tunnel exhaust is the most engineering-intensive single duct duty in a foam manufacturing facility. The tunnel is 30 to 80 metres long, 2 to 3 metres wide and 1.5 to 2.5 metres tall, with foam mix deposited at one end and the finished bun emerging at the other. Exhaust take-off positions and flow rates determine whether the mix-head and bun-cutter operator stations are exposed to isocyanate above the Safe Work STEL.

SBKJ specifies four to six exhaust take-off positions — mix-head over-spray hood (highest concentration), cream-rise station, gelation station, cure station, and tunnel exit. Each take-off sized for local emission rate and local operator exposure target. Combined extract flow for a 60-metre tunnel typically 25,000 to 60,000 m3/hour. Manifold diameter sized at 12 to 15 m/s conveying velocity at design flow (lower than dust extraction because contaminant is gaseous). SBKJ specifies the manifold in 1.5 mm 316L stainless spiral, 600 to 1000 mm diameter, TIG-welded seams, insulated external to maintain wall temperature above 65 °C (above the dew point at typical isocyanate and amine vapour partial pressure), electrically bonded throughout. The abatement equipment interface (thermal oxidiser or activated carbon scrubber from Anguil, Dürr or local Australian specialist) connects to the SBKJ duct at the abatement OEM flange. Discharge stack downstream is 304L because chemistry is much reduced after 95 to 99 percent destruction (TO) or 90 to 95 percent capture (carbon bed).

10. Latex foam moulding exhaust — engineering depth

The latex moulding exhaust is dominated by ammonia capture, with secondary duties for SO2, fluorosilicate dust and water vapour. Dominant operator exposure is at the latex weigh room, pour station, mould transfer and demould station.

SBKJ specifies dedicated local exhaust at each workstation — weigh (1.0 m/s capture, 1,500 to 3,000 m3/h), mix (1.0 m/s, 2,000 to 4,000 m3/h), pour (1.5 m/s because open pour releases concentrated ammonia, 3,000 to 6,000 m3/h), mould transfer (1.0 m/s, 1,500 to 3,000 m3/h) and demould (1.5 m/s because residual ammonia release is high, 3,000 to 6,000 m3/h). Combined local exhaust for a typical line 15,000 to 30,000 m3/h. The vulcanising oven exhaust is separate because of the higher water-vapour content — SBKJ specifies 1.5 mm 316L, 400 to 600 mm diameter, TIG-welded seams, external insulation, direct to ammonia scrubber. The scrubber is a packed-bed wet scrubber using dilute sulphuric acid (5 to 10 percent) or citric acid (5 to 15 percent) absorbent. Scrubber blow-down collected for Trade Waste discharge or (larger plants) ammonium sulphate recovery for fertiliser sale. Scrubber outlet duct is 1.5 mm 304L (cleaned gas chemistry much less aggressive).

11. AS 1530.3 lining and AS 1668.2 ventilation interface

The mattress and bedding industry has a unique interface between AS 1530.3 fire performance and AS 1668.2 ventilation. Finished products (mattresses, pillows, quilts) are themselves regulated for flammability under AS/NZS 4088 and AS 5811, with foam additive package, fabric chemistry and barrier layer driven by the consumer-product flammability target. The same chemistry becomes the dust load in the HVAC duct system at cutting, profiling, quilting and assembly. SBKJ specifies AS 1530.3 Group 1 ductwrap and ductliner on all production-area HVAC, ensuring a hypothetical duct fire — from fan bearing, hot bearing, electrostatic discharge or propagating deflagration — does not spread along the duct line faster than the surrounding production space would burn. The Group 1 lining contributes less smoke per unit mass burned than the Group 2 lining previously the minimum, reducing operator escape time impairment in the unlikely event of a duct fire.

12. Capacity sizing — typical Australian plant types

The Australian mattress and bedding industry runs at four scale tiers, with the HVAC duct package complexity and the SBKJ-supplied machine configuration matched to the tier.

12.1 Small foam converter — 500 to 2000 m² plant

One or two CNC contour cutters, block saw, occasional hot-wire profiler, packaging area. Capacity 5 to 20 tonnes/week. Duct package: 80 to 200 metres galvanized spiral, no stainless (no slabstock tunnel), no spray finishing. Single mid-size dust collector with deflagration venting. Spark detection at one location (CNC cutter branch). SBKJ deploys SBFB-1500 spiral former, SBSF-1525 flanging, manual TIG for touch-up.

12.2 Mid-tier bedding fabricator — 2000 to 8000 m² plant

Multiple foam cutting and contouring, quilting line, pillow filling line, mattress assembly, bedhead fabrication, innerspring assembly, compression packaging. Capacity 30 to 100 tonnes/week. Duct package: 400 to 1200 metres galvanized spiral, 80 to 200 metres 304L stainless on bedhead spray booth and innerspring tempering exhaust. Two or three dust collectors, spark detection at three to six locations. SBKJ deploys SBAL-V auto duct line, SBFB-1500, SBSF-1525, manual TIG for stainless construction.

12.3 Integrated mattress and bedding plant — 8000 to 25000 m² plant

Mid-tier scope plus additional fabric printing/quilting, larger pillow and quilt assembly volume, multiple bedhead spray booths, finished goods warehouse. Some plants operate in-house slabstock or moulded foam. Capacity 100 to 400 tonnes/week. Duct package: 1200 to 3000 metres galvanized spiral, 300 to 800 metres 304L stainless, 100 to 300 metres 316L on small slabstock tunnel where present. Four to seven dust collectors, spark detection at six to twelve locations. SBKJ deploys full SBAL-V auto duct line, SBFB-1500, SBSF-1525, automated TIG seam welder, SBKJ duct insulation line.

12.4 Dedicated slabstock or latex foam plant — 5000 to 30000 m² plant

Continuous foam production with primary process tunnel (slabstock or latex moulder), bulk chemical storage, curing area, limited downstream conversion. Capacity 200 to 1500 tonnes/week. Duct package: 800 to 2500 metres 316L stainless on foaming tunnel and chemical-handling exhausts, 400 to 1000 metres 304L on curing tunnel and ancillary, 200 to 800 metres galvanized spiral on in-house conversion. Two to four dust collectors plus tunnel exhaust abatement (thermal oxidiser or activated carbon for PU, ammonia scrubber for latex). Spark detection at four to eight locations. SBKJ deploys full plant including automated TIG seam welder and duct insulation line for extensive 316L external insulation.

13. Energy and air management

Dust extraction and chemical-capture exhaust consume significant electrical energy through exhaust fans, dust collector pulse-jet compressed air, abatement equipment fans and make-up air supply fans. SBKJ specs include VFD control on main exhaust fans, with speed modulated against production rate (number of cutters running, branches open) and measured static pressure at the dust collector inlet. Make-up air must replace extract at conditioned temperature and humidity year-round to maintain operator comfort, foam dimensional stability and adhesive bond integrity — conditioning load 60 to 120 kW per 10,000 m3/h extract in Australian climates. SBKJ specifies heat-recovery on make-up air where extract chemistry permits — plate heat exchanger on quilting and pillow filling extracts, rotary on office and warehouse. Heat recovery not viable on slabstock tunnel or latex moulding exhaust (chemistry would cross-contaminate). Air balance net negative (extract 5 to 10 percent over supply) for contaminant containment.

14. Acoustic case — slabstock plant and quilting line

Two zones in a mattress and foam facility have particularly demanding acoustic requirements. The slabstock tunnel exhaust fan operates at 50,000 to 100,000 m3/h and 1,500 to 3,000 Pa, motor 30 to 100 kW. Blade-pass frequency at 1,470 rpm centrifugal impeller is 245 Hz, with strong tonal noise at 245 Hz and harmonics. Without treatment the fan generates 95 to 105 dB(A) at one metre. SBKJ specifies a packed dissipative silencer immediately downstream of the fan (20 dB insertion loss at 250 Hz band) plus acoustic enclosure around the fan body (15 dB transmission loss at the same band). The quilting line multi-needle quilter generates 90 to 95 dB(A) impact noise at the operator position. SBKJ specifies acoustic supply ducts with 50 mm internal acoustic lining, NC-50 maximum at the supply diffuser.

15. Cyclone, baghouse and cartridge collector selection

Dust collector selection is driven by dust load characteristics — particle size distribution, fines fraction, dust loading at inlet, abatement target (zero visible emission to atmosphere is typical SBKJ spec, with local EPA limit as compliance ceiling). For foam pulveriser and grinder circuits with high coarse-particle loading, SBKJ specifies primary cyclone (1.6 mm galvanized G90 with abrasion-resistant inlet elbows) feeding a secondary cartridge or baghouse collector for fines. For foam cutting (CNC, hot-wire, block saw) and quilting circuits with dominantly fine dust, SBKJ specifies cartridge collector with cleanable pleated cartridges (filter area 30 to 80 m2 per cartridge, total 200 to 800 m2 per collector). For pillow filling, quilt/doona filling and feather circuits, SBKJ specifies baghouse with shaker or pulse-jet cleaning at 0.8 to 1.2 m3/min air per m2 filter area. Every collector handling combustible foam, fibre, lint or feather is fitted with NFPA 68 deflagration venting; where venting to a safe area is not feasible, NFPA 69 chemical suppression is fitted. SBKJ supplies the duct interface to the collector inlet flange and the discharge ductwork from collector outlet to make-up air return or atmospheric discharge stack.

16. Australian sector cases — integrated mattress, slabstock, latex, pillow and memory foam

The Australian mattress and bedding sector divides into six operator types, each with a slightly different HVAC emphasis.

• Integrated mattress manufacturer (Sealy Australia at Padstow NSW, A.H. Beard at Padstow NSW, Sleepmaker at multiple sites) — end-to-end production from raw material inlet to finished product despatch. Full HVAC scope spanning galvanized dust extraction, 304L stainless on bedhead spray finishing and innerspring tempering oven, supply and return HVAC, warehouse and showroom. SBKJ deploys variable-frequency drive on every main exhaust fan, with speed modulated against measured static pressure at the dust collector inlet, to accommodate retail-order-driven production-rate variability.
• Dedicated polyurethane slabstock manufacturer (Joyce Foam Products at Wetherill Park NSW, Dunlop Foams at Padstow NSW, Foam Products Group at multiple sites) — continuous slabstock production plus downstream foam conversion. HVAC dominated by 316L stainless slabstock tunnel exhaust, 316L chemical handling exhaust, 304L curing tunnel exhaust and galvanized G90 in-house conversion dust extraction. SBKJ specification includes precise local-exhaust flow control at the mix head and cream-rise station, with damper position correlated to foaming chemistry and production-rate target.
• Latex foam manufacturer (limited number of Australian Dunlop latex producers, plus imports of Talalay latex from Vita Talalay European supply chain) — latex moulding with ammonia capture dominating exhaust duty. SBKJ supports with 316L stainless ammonia exhaust and wet scrubber interface, including scrubber blow-down management as Trade Waste or fertiliser-feedstock recovery.
• Pillow and quilt manufacturer (Tontine at Frankston VIC, MiniJumbuk at Naracoorte SA, Joyce Bedding at multiple sites) — filling line, quilting line, sewing assembly and packaging. Down and feather circuits drive elevated 22 m/s conveying velocity, 4-week duct cleaning interval, and spark detection sensitivity set to the down ignition energy (below 10 millijoules) rather than the generic foam dust ignition energy.
• Memory foam manufacturer (Tempur Australia at Castle Hill NSW, ergoflex import-based product, local viscoelastic foam moulder base) — viscoelastic slabstock or moulded production. HVAC similar to standard polyurethane slabstock with 316L on foaming tunnel, 304L on curing tunnel and moulded press station local exhaust. Memory foam dust at cutting station has lower MIE than standard PU foam (15 to 25 mJ versus 25 to 40 mJ), driving tighter spark detection sensitivity.
• Bedhead and bedroom furniture manufacturer — timber substrate fabrication, foam wrap, fabric stretch and (on premium pieces) spray finishing. Combined foam-and-timber dust profile drives NFPA 68 vent sizing against the higher Kst of the two dusts. Cross-reference our Custom Joinery, Cabinetmaking and Furniture HVAC Duct Engineering Guide for the timber-side scope.

17. The bed-in-a-box phenomenon and the export market

The bed-in-a-box format has transformed the mattress retail channel since the mid-2010s. Koala Mattress (Sydney-based, contract manufactured at multiple Australian sites), Ecosa, Sleeping Duck, Eva Sleep and the broader DTC channel ship vacuum-rolled product direct to consumer. The compression packaging line is an additional process zone — hydraulic press compresses the finished mattress to 25 percent of original volume, minor oil mist captured at 1.0 m/s overhead spot exhaust, branch 150 to 200 mm at 18 m/s, galvanized G90.

The Australian mattress and bedding sector exports premium product to Asia, Pacific Islands and the Middle East. The export market drives emphasis on consistent finishing quality, controlled-humidity finished goods warehouse, and traceability of foam additive package (for compliance with destination-country REACH-equivalent provisions). The HVAC supports these requirements with controlled-humidity warehouse, integrated bedhead spray booth and documented dust collector emission profile for chemical compliance reporting.

18. Commissioning, documentation and ongoing certification

The SBKJ commissioning protocol follows a 14-day on-site schedule. Days 1-3 mechanical install verification (flange alignment, gasket integrity, bonding continuity, isolation valve actuator). Days 4-6 flow commissioning (branch flow at every capture point, main flow at every section, balancing dampers and blast gates set). Days 7-9 containment verification (smoke test at every capture hood, capture velocity at four points per hood face, conveying velocity at worst-case main). Days 10-12 protection verification (spark detection functional test, isolation valve closure-time, deflagration vent panel inspection, bonding measurement at every flange). Days 13-14 documentation handover (as-built drawings, ductwork register, bonding results, flow measurements, spray booth face velocity, slabstock tunnel exhaust profile, latex moulding capture verification, AS 3957 DHA interface, NFPA 660 compliance summary, AS 4114 booth certification where applicable, O&M manual including 5-year DHA refresh schedule). Ongoing certification under the AS 3957 DHA refresh cycle requires re-validation every 5 years and after any process modification. SBKJ supports with documentation re-issue, on-site re-measurement of bonding and flow, and inspection of deflagration vent panels and isolation valve mechanisms.

19. How SBKJ scores against the Australian mattress and foam manufacturing brief

We use this guide as the engineering reference when customers ask us to quote a mattress, bedding, pillow, quilt, bedhead, furniture foam, memory foam or latex foam manufacturing duct package at our Box Hill North VIC office. The short version:

• Process zone engineering. Full site walk and zone schedule on every quotation. DHA coordination with the facility's AS 3957 consultant and the polyurethane chemistry partner.
• Hazardous area drawing. AS/NZS 60079.10.1 and AS/NZS 60079.10.2 plan and elevation per quotation, Zone 1/2/20/21/22 boundaries marked, plus AS 4332 ammonia volume where latex is in scope.
• Material specification. Galvanized G90, 304L, 316L each justified per duty. 316L at every slabstock tunnel, isocyanate and ammonia exhaust as standard.
• Conveying velocity. Sized at peak operating condition. 22 m/s CNC contour cutter, 18 m/s hot-wire profiler, 20 m/s quilting and pillow filling, 22 m/s feather, 18 m/s bedhead sander.
• Bonding and earthing. Copper bonding strap and brass M8 lug welded to every spiral section at SBKJ. Under 1 ohm per joint, under 10 ohms system to plant earth.
• Spark detection. Sensor location, water injection or fast-acting damper response, dust collector interface — all specified at quotation.
• Slabstock and latex tunnel exhaust capability. Full 316L TIG-welded construction, external insulation, abatement interface (thermal oxidiser, activated carbon or ammonia scrubber) at the SBKJ package boundary.
• NFPA 660 / NFPA 68 / NFPA 33 interface. Vent and isolation valve flanges welded into the SBKJ package at the factory. AMCA 99 conformity on every SBKJ-supplied fan.
• AS 1530.3 lining specification. Group 1 ductwrap and ductliner on every fire-rated and occupied-zone duct run.
• Machine configuration. SBAL-V auto duct line, SBFB-1500 spiral former, SBSF-1525 round tube flanging, TIG seam welder for leak-tight stainless. Full SBKJ machine catalogue.
• Australian footprint. Box Hill North VIC engineering and fabrication, Australian site walks, commissioning, after-sales. About SBKJ Group.

Get an itemised SBKJ duct package quotation for your mattress, bedding, pillow, quilt, bedhead or foam manufacturing project →

FAQ

Why is polyurethane foam dust treated as combustible?

Foam dust under 500 microns has MIE below 30 mJ and Kst between 110 and 180 bar·m/s. Under AS 3957 and NFPA 660 every facility above the threshold quantity needs a DHA, spark detection at ignition-source machinery, NFPA 68 explosion venting at the dust collector, and full bonding under 10 ohms to earth.

What duct material does a polyurethane slabstock tunnel exhaust need?

316L stainless from the tunnel take-off to the abatement equipment. TDI/MDI isocyanate plus amine catalyst plus elevated temperature drives 304L pitting within 3 to 5 years; 316L with 2.0 to 3.0 percent molybdenum eliminates the failure mode. TIG-welded seams and external insulation.

What duct material does a latex foam moulding exhaust need?

316L stainless because ammonia plus water vapour plus chloride trace from natural latex is mildly aggressive to 304L over 18 to 30 months. 1.5 mm 316L spiral, TIG-welded seams, conductive gaskets, full electrical bonding, discharging through a wet ammonia scrubber.

How fast does galvanized duct fail in a bedhead spray booth exhaust?

12 to 24 months on a solvent-borne booth, 18 to 30 months on a paint mix room. Solvent condensate attacks zinc, rate accelerated by temperature cycling. 304L stainless eliminates the failure mode.

What is the conveying velocity for foam cutting and quilting?

CNC contour cutter 22 m/s, hot-wire profiler 18 m/s, foam grinder 22 m/s, quilting line 20 m/s, pillow filling 20 m/s (22 m/s for feather and down), bedhead sander 18 m/s. Sized at peak operating condition. Below SBKJ targets the system settles, the deposit ignites, and the next spark propagates.

What is the Safe Work exposure limit for TDI, MDI and ammonia?

TDI STEL 0.005 ppm. MDI STEL 0.02 ppm, TWA 0.005 ppm. Ammonia STEL 35 ppm, TWA 25 ppm. There is no known safe respiratory exposure level for isocyanate — sensitisation is permanent once it occurs. Capture must be complete: 316L stainless on every isocyanate and ammonia exhaust, AMCA 99 Type B spark-resistant fan, abatement before discharge.

What is the AS 4114 face velocity for a bedhead spray booth?

0.5 m/s minimum for solvent-borne, 0.4 m/s for waterborne, 0.6 to 0.75 m/s for 2K polyurethane. Cross-draft or semi-downdraft is the typical configuration. AMCA 99 Type B spark-resistant fan minimum, 304L stainless exhaust duct.