Glass and Mirror Manufacturing HVAC Duct Guide — Float, Tempering, Laminating, Mirror Coating, IGU and Decorative Glass

Why glass and mirror plant HVAC is its own discipline

A modern Australian glass plant is a contradiction. The cutting bench is a precision instrument; the tempering furnace is a metalwork-scale heat engine; the mirror coating cleanroom is a semiconductor cousin; and the cullet bay is a recycling depot with a documented fire history. One HVAC ductwork specification has to bind all of them together while keeping operators below the Safe Work Australia respirable crystalline silica workplace exposure standard of 0.05 mg/m3 and keeping the plant compliant with AS 1668.2 mechanical ventilation, AS 4254 ductwork construction, AS 1530.4 fire-rated penetrations and the relevant product standards across AS 1288, AS 2208, AS 4666, AS 4055, ISO 12543, EN 12150 and EN 14179.

Most engineers coming into glass plant HVAC from commercial or warehouse work are surprised by three things. First, silica dust is the dominant compliance driver — not heat, not noise, not VOC. Get the silica capture wrong on a cutting bench and you fail the next Safe Work Australia health audit. Get it right and the rest of the plant scope tends to fall into place. Second, the materials map is non-trivial. Galvanised G300 with Z275 zinc coating covers about 70 percent of duct length, but the remaining 30 percent — mirror back paint extract, HF acid etch, tempering furnace exit, mirror wet silvering, cullet baghouse on contaminated feed — sits in 304L stainless, 316L stainless or welded heavy-gauge mild steel. Specifying the wrong material on any one of these lines means a 12-month service life on a duct that should last 25 years. Third, the SBKJ duct machinery scope has a hard ceiling at 1.5-1.6 mm sheet thickness. Above that — high-temperature tempering furnace roof exhaust, large-diameter cullet conveyor stiffener, refractory-lined annealing lehr stack — the work moves to plate rolling and submerged-arc welding equipment outside the standard SBAL-V and SBTF range.

This guide walks through every zone in a typical Australian glass and mirror plant, in the order the air actually moves through the building. We start at the cutting bench (because silica RCS is the first compliance gate), move through edge grinding, tempering, laminating, mirror coating, IGU assembly and decorative glass acid etching, then close out with container glass, automotive glass and cullet handling. For each zone we name the standard that governs it, the air change rate that satisfies it, the duct material that suits it, the pressure class it falls in under AS 4254, and the specific SBKJ machine (SBAL-V, SBAL-III, SBAL-II, SBTF-1500C, SBTF-1602, SBTF-2020, SBEM-1250, SBSF-1525, SBFB-1500, SBHF ovalizer, SBPC1500 plasma, SBLR-600 ring rolling) that fabricates the duct for it. The whole guide is written from the Box Hill North VIC engineering office where SBKJ's Australian team replies to glass plant HVAC duct questions within 12 hours.

Australian glass and mirror operators — the specifying landscape

Australia's glass industry is concentrated and identifiable. Knowing which operator runs which line determines how a mechanical services contractor sizes a duct fabrication shop and which SBKJ machines belong in it. The list below is the practical specifying landscape as it stands at ARBS 2026.

Viridian Glass

Viridian Glass is the largest Australian-headquartered architectural glass processor, originally a CSR Limited (ASX:CSR) division and now operating across Ingleburn NSW and Dandenong VIC processing lines. Viridian runs cutting, edge grinding, drilling, washing, tempering, laminating, IGU assembly and silvered mirror production. Viridian-branded ComfortPlus and SuperGreen low-emissivity products feed the Australian residential and commercial construction market via Viridian RAW and Viridian Resi distribution. HVAC retrofit at Viridian plants tenders to mechanical services contractors during planned shutdown windows. The duct scope split is the classic glass-plant pattern: SBAL-V galvanised on personnel-zone supply and return, 304L stainless on mirror back paint extract and laminating bay clean room HEPA terminal housings, heavy-gauge welded on the tempering furnace exit.

Pilkington Australia

Pilkington Australia is part of NSG Group (Nippon Sheet Glass), operating from Dandenong VIC. The Australian footprint covers laminated safety glass and toughened glass processing for automotive, architectural and specialty applications. Pilkington was the pioneer of the float glass process globally; the Australian operations focus on downstream processing of imported float ribbon. HVAC scope at Pilkington Dandenong includes cutting bench silica capture, tempering furnace exhaust, laminating bay clean room HVAC and a small mirror coating cell for back-silvered automotive mirrors. SBKJ SBAL-V machinery is the appropriate fit for the mechanical services contractor pool that bids Pilkington shutdown windows.

G.James Glass and Aluminium

G.James Glass and Aluminium is a Brisbane-headquartered family-owned group operating glass processing and architectural aluminium fabrication plants across Brisbane (Eagle Farm, Yatala), Sydney, Melbourne, Adelaide, Perth and Townsville. The glass business runs IGU assembly, tempering, laminating and silvered mirror production. G.James is one of the largest privately owned glass and aluminium fabricators in Australia. HVAC duct fabrication for G.James shutdown windows is typically tendered to in-house and contracted mechanical services teams who run SBAL-V or equivalent auto duct lines in their own facilities.

O-I Glass Australia

O-I Glass (Owens-Illinois) operates the Penrith NSW container glass plant — the largest container glass operation in Australia, producing wine bottles, beer bottles, spirits bottles and food jars for Penfolds, Treasury Wine Estates, Lion Beverages, Coopers and Bickfords. The plant runs multiple Individual Section (IS) machine lines, regenerative furnaces and annealing lehrs. HVAC retrofit at O-I Penrith tenders to mechanical services contractors during the 4-6 week major furnace shutdown windows that recur every 8-12 years and the 1-2 week minor shutdowns that recur annually. The duct scope split is classic container glass: SBAL-V galvanised on batch house personnel zone and IS machine operator pulpit supply, 304L stainless on cold-end stearate coating exhaust and IS machine swabbing oil mist, heavy-gauge welded on the regenerative furnace stack.

Visy Glass and AGI Glass Pack

Visy Glass operates the Penrith NSW container glass operation in conjunction with O-I (the 2024 restructure brought Visy Glass Recycling cullet streams into the O-I container operation). AGI Glass Pack is the container glass operator that historically traded under the Anchor Glass and ACI brands; current ownership and naming conventions vary across the Australian container glass landscape. Cullet processing and recycling are integrated with container manufacture, with cullet plants in Sydney Smithfield, Brisbane Wacol and Melbourne Reservoir.

Saint-Gobain Australia

Saint-Gobain Australia (Sydney) covers automotive glass processing through the Sekurit business unit, architectural glass distribution and a related insulation business. The automotive glass operations service the Australian original equipment vehicle market (limited domestic OEM after Toyota and Ford ceased Australian assembly) and the larger aftermarket replacement market through SafetyGlass Australia and AGC distribution. HVAC scope at Saint-Gobain Australia is concentrated on cutting bench silica capture, automotive glass tempering and laminating bay clean room HVAC.

Cardinal IG Australia

Cardinal IG (Cardinal Glass Industries) is a North American multinational with Australian distribution and limited fabrication for insulating glass units. Cardinal LoE2-272 and LoE3-366 low-emissivity coatings are widely specified in Australian architectural projects. Cardinal IG Australia fabrication runs IGU assembly with butyl primary seal and silicone or polysulphide secondary seal, requiring a controlled clean room HVAC environment per AS 4666 insulating glass units.

Australian Glass Group, Bristol Glass, Crystal Mirror

The Australian Glass Group (AGG) is a Melbourne-based glass processor running cutting, edge polishing and IGU assembly. Bristol Glass is a Sydney-based architectural glass processor. Crystal Mirror (NSW) is a specialist mirror manufacturer running wet silvering and mirror back paint application. Each of these mid-sized operators tenders HVAC retrofit work to local mechanical services contractors who typically run an SBAL-III or SBAL-II auto duct line for in-house fabrication.

Glass Industries Australia, Float Glass Industries, Smart Decorative Glass

Glass Industries Australia (Western Australia) is a Perth-based glass processor serving the WA architectural market. Float Glass Industries is a NSW-based downstream processor partnered with Pilkington for float ribbon supply. Smart Decorative Glass focuses on the decorative glass segment with acid etching, sandblasting and back-painted decorative glass production — a segment where HF acid extraction and 304L stainless ductwork are mandatory.

Vetro Smart Glass, Schweitzer Glass, Custom Glass Solutions

Vetro Smart Glass produces switchable PDLC (polymer dispersed liquid crystal) and electrochromic smart glass for premium architectural projects. Schweitzer Glass is a specialty architectural glass fabricator. Custom Glass Solutions provides bespoke glass cutting and edge processing for design-led architectural projects. These specialty operators are smaller in volume but specify high-grade HVAC because the product margin supports it.

Metro Performance Glass NZ and trans-Tasman supply

Metro Performance Glass operates from Auckland NZ and supplies the Australian architectural glass market across the Tasman, with toughening, laminating and IGU assembly capability. HVAC duct retrofit demand at Metro is fed by Auckland and Wellington-based mechanical services contractors who source SBKJ machinery through the same trans-Tasman shipping routes (port of Auckland and port of Wellington) as Australian customers.

Easternwell, Bormioli Luigi and adjacent specifiers

Easternwell supplies glass machinery into Australian glass processors. Bormioli Luigi is an imported container glass brand with Australian distribution. Australian Window Association (AWA) members and Glass and Glazing Association of Australia (GGAA) members across the residential and commercial fenestration industry all draw from this operator pool when specifying HVAC retrofit work. The mechanical services contractor base supplying these operators is the realistic customer pool for SBKJ duct machinery in Australia.

Standards and regulatory framework

Glass and mirror plant HVAC sits at the intersection of more than a dozen Australian and international standards. The framework below is the practical specifier's cheat sheet.

AS 1668.2-2024 — mechanical ventilation

AS 1668.2 The use of mechanical ventilation and air-conditioning in buildings is the master Australian standard for occupied-building ventilation design. Section 5 covers general exhaust ventilation (personnel zones, factory floor dilution), Section 6 covers specific exhaust applications (silica dust, VOC capture, paint spray booths), and the appendices give application-specific guidance. Most glass and mirror plant HVAC ductwork sits inside Section 5 (personnel comfort) and Section 6 (process exhaust). Air-tightness and pressure class requirements cross-reference AS 4254.

AS 4254 — ductwork construction

AS 4254 Ductwork for air-handling systems in buildings is the construction standard for sheet metal duct. Part 1 covers flexible duct; Part 2 covers rigid duct. AS 4254.2 sets pressure classes A through E (up to 2500 Pa positive on Class C, higher on Class D-E), air-tightness leakage classes A through C, reinforcement schedules, gauge selection and seam types. Pittsburgh seam satisfies Class A through C; longitudinal welded seam is required for Class D-E and for any leak-class A air-tightness on stainless. SBAL-V output meets AS 4254 Class C up to 2500 Pa as standard on Pittsburgh seam.

AS 1530.4 — fire-rated penetrations

AS 1530.4 Methods for fire tests on building materials, components and structures — Fire-resistance tests of elements of construction is the Australian test standard for fire-rated wall and floor penetrations. Any HVAC duct passing through a fire-rated wall or floor between two glass plant compartments needs an AS 1530.4 tested and certified penetration seal — typically intumescent mastic, fire-rated collars or ceramic-fibre blanket pillows. SBAL-V galvanised duct is the standard substrate; the rating is delivered by the penetration seal product, not the duct itself.

NFPA 86 — industrial furnace ventilation

NFPA 86 Standard for Ovens and Furnaces governs combustion safety, purge volume, exhaust design and safety interlocks for fuel-fired industrial ovens and furnaces. Glass tempering furnaces (600-700 degrees Celsius), annealing lehrs (540 degrees Celsius inlet down to 100 degrees Celsius outlet), float glass annealing lehrs and laminating autoclaves all sit within NFPA 86 scope to varying degrees. Exhaust train design — purge volume calculation, combustion-safety interlocks, exhaust stack sizing — is governed by NFPA 86 Chapter 8. Australian glass operators typically run NFPA 86 in parallel with AS 4041 piping code and AS 1228 boiler code for combustion-side safety.

NFPA 654 — combustible dust

NFPA 654 Standard for the Prevention of Fire and Dust Explosions from the Manufacturing, Processing, and Handling of Combustible Particulate Solids governs deflagration risk assessment for combustible dust. Pure silica sand, soda ash, limestone and dolomite are non-combustible and exempt. Cullet contaminated with organic residue (label paper, plastic closures, food residue) falls within NFPA 654 scope at dust layer thickness above 0.4 mm. Engineering controls include explosion vents on the cullet baghouse hopper sized per NFPA 68, isolation valves between dust collectors and process equipment, electrostatic grounding on all duct and equipment, and a documented dust hazard analysis.

AS 3957 and NFPA 660 — silica dust

AS 3957 covers workplace dust exposure controls for construction and demolition; the Safe Work Australia workplace exposure standard for respirable crystalline silica is 0.05 mg/m3 as an 8-hour time-weighted average. NFPA 660 (the new consolidated combustible dust standard published from 2024) merges the previous NFPA 61, 484, 652, 654, 655 and 664 commodity-specific dust standards into a single document with general requirements common to all combustible dust. Silica respirable crystalline is non-combustible but the OSHA and Safe Work Australia exposure standards are the dominant compliance driver. Personal monitoring methodology follows AS 3640.

AS 4775 — emergency eyewash and shower

AS 4775 Emergency eyewash and shower equipment covers the design, installation and testing of emergency eyewash and safety shower stations. Mandatory at every decorative glass HF acid etching workstation, mirror wet silvering tank, ammonia mirror coating stripping station and any other chemical workstation in the plant. Eyewash flow rate 1.5 L/min minimum, shower flow rate 75 L/min minimum, tepid water at 16-38 degrees Celsius, audible and visual alarm on activation.

ISO 12543 — laminated safety glass

ISO 12543 Glass in building — Laminated glass and laminated safety glass governs the product specification for laminated safety glass with PVB, EVA or SentryGlas interlayer. Parts 1 through 6 cover definitions, test methods, durability, edge stability, dimensions and impact performance. Laminating bay HVAC has to maintain the controlled environment that allows the product to pass the ISO 12543 durability tests — humidity, temperature, dust and contamination all matter.

AS 2208 — safety glass

AS 2208 Safety glazing materials in buildings is the Australian standard for safety glass — covers toughened glass, laminated glass and the impact test classification (Grade A, B and C). The product is what matters for the customer; the HVAC has to provide the controlled manufacturing environment that delivers it.

AS 1288 — glass in buildings

AS 1288 Glass in buildings — Selection and installation is the Australian standard for selecting glass type and thickness for human-impact safety, wind loads and overhead glazing. Cross-references AS 2208 for safety glass classification and AS 4055 for residential wind loading. The product application drives back to the manufacturing process which drives back to the HVAC controlled environment.

AS 4666 — insulating glass units (IGU)

AS 4666 Insulating glass units sets the construction, durability and longevity requirements for double-glazed and triple-glazed insulating glass units. Spacer selection (aluminium, stainless steel, warm-edge polymer or thermoplastic spacer), desiccant fill (molecular sieve), primary seal (butyl) and secondary seal (silicone, polysulphide or polyurethane) all have to meet AS 4666 to qualify the unit for Australian commercial and residential building approval. IGU assembly HVAC has to deliver the controlled clean room environment that allows the unit to pass the AS 4666 durability tests over 25-year design life.

AS 4055 — wind loading for glazing

AS 4055 Wind loads for housing classifies Australian residential wind exposure into N1 through N6 (non-cyclonic) and C1 through C4 (cyclonic) categories. Glass thickness selection per AS 1288 cross-references the AS 4055 wind classification. From an HVAC perspective, AS 4055 matters only insofar as it drives the product specification that drives the manufacturing process and therefore the HVAC environment.

ASHRAE Applications Chapter 28 and Chapter 33

ASHRAE Applications Chapter 28 Industrial Ventilation provides design guidance for general industrial ventilation, dust capture, fume capture and source-capture local exhaust ventilation. Chapter 33 Laboratories covers cleanroom HVAC design including the temperature, humidity, pressure and air-change requirements for ISO 14644 Class 5 through Class 9 cleanrooms. Mirror sputter coating uses Chapter 33 cleanroom design principles applied to ISO 14644 Class 7-8.

ISO 14644 — cleanrooms

ISO 14644 Cleanrooms and associated controlled environments parts 1 through 17 cover cleanroom classification, design, testing, monitoring and operation. ISO 14644-1 defines particle count limits for Class 1 through Class 9. Mirror sputter coating runs at Class 7-8 in load-lock and transport, with Class 6 conditions in the sputter chamber that does not need general HVAC. ISO 14644-4 covers cleanroom design and construction.

EN 12150 and EN 14179 — thermally toughened glass

EN 12150 Glass in building — Thermally toughened soda lime silicate safety glass is the European standard for thermally toughened (tempered) glass, often referenced in Australian specifications alongside AS 2208. EN 14179 Heat soaked thermally toughened glass covers the additional heat soak test that detects nickel sulfide inclusions which cause spontaneous breakage in toughened glass. The product is what matters for the customer; the HVAC has to deliver the temperature stability that allows the toughening and heat soak processes to run within their tolerance bands.

Flat glass processing HVAC — the architectural workhorse

Flat glass processing is the dominant Australian glass plant type by floor area, by HVAC duct length and by mechanical services contractor work-hours. Australia has historically not run a float line (most float ribbon is imported through Saint-Gobain, AGC and Pilkington supply chains), but the downstream processing of cutting, edge grinding, drilling, washing, tempering, laminating and IGU assembly is the substantive Australian operation. Viridian, Pilkington Australia, G.James, Bristol Glass, Australian Glass Group, Custom Glass Solutions, Metro Performance Glass NZ and dozens of regional processors run this work.

Process flow and HVAC zoning

The standard flat glass processing flow runs from the raw stock racks (imported float glass ribbon cut to standard sizes 3210 x 2250 mm or larger) through cutting bench, breakout table, washing line, edge grinder, drill press, tempering furnace (if toughened product), laminating line (if laminated product), IGU assembly (if double-glazed product), packaging and despatch. Each step is an HVAC zone with its own air-change and exhaust requirements.

The flat glass processing factory floor typical layout is open-plan with 10-12 metre ceiling height to accommodate overhead crane handling of large jumbo glass sheets. General factory dilution at 6-8 air changes per hour is the AS 1668.2-aligned baseline, with local exhaust capture at every cutting, edge grinding, drilling, sandblasting and decorative-paint workstation. Acoustic budget NC-50 across the open floor, NC-40 in QA and inspection. Personnel comfort 22-24 degrees Celsius ambient, 45-65 percent relative humidity through the year, with seasonal adjustment for Sydney, Melbourne, Brisbane, Adelaide and Perth climate zones.

Material selection for the open floor

Galvanised G300 with Z275 zinc coating is the standard material for the open factory floor supply and return duct. Forms readily on the SBAL-V at 0.5-1.5 mm with no tooling change between gauges. SBTF spiral pipe at 80-1500 mm diameter handles the long return-air mains running parallel to the production line. The flat-oval transition via the SBHF ovalizer accommodates low-headroom runs above the cutting benches where overhead clearance under the crane rail is tight.

Pressure class and air-tightness

Personnel-comfort supply and return at AS 4254 Class A-B (up to 500 Pa). Process exhaust mains feeding the cutting and edge grinding bag filter at Class C (up to 2500 Pa). Mirror coating cleanroom HEPA-filtered supply at Class A with leak-class A air-tightness. Tempering furnace exhaust outside AS 4254 — sits in NFPA 86 territory. SBAL-V output meets Class C as standard; for the cleanroom HEPA terminal housings the SBKJ duct welding line provides longitudinal welded seam to leak-class A.

Cutting, edge grinding and silica capture — the compliance gate

Glass cutting, edge grinding, drilling and sandblasting generate respirable crystalline silica. Every glass plant in Australia has to demonstrate silica RCS engineering controls that keep operators below the Safe Work Australia workplace exposure standard of 0.05 mg/m3 8-hour TWA. Get the silica capture wrong and the next Safe Work Australia health audit fails. Get it right and the rest of the plant scope tends to fall into place.

Wet cutting vs dry cutting

Modern flat glass cutting uses CNC cutting tables with a small water mist applied to the scribe line to suppress silica dust. The water mist is sufficient on the cutting head itself, but the breakout, snap and edge work that follow still generate dust. Edge grinders, edge polishers, drill presses and sandblasting cabinets are the heavier silica sources. Dry cutting is rare in modern flat glass processing but persists in some decorative glass and small-batch specialty work where water contamination of the product would scrap the batch.

Local exhaust capture design

Every cutting bench, edge grinder, drill press and sandblast cabinet gets a dedicated local exhaust hood. Hood face velocity 1.0-1.5 m/s per ASHRAE Applications Chapter 28 and ACGIH Industrial Ventilation Manual recommendations for silica service. Capture distance kept short — within 300-500 mm of the work surface — because silica is dense and falls quickly out of a low-velocity airstream. Hood design selected by the workstation: lateral exhaust slot on a linear cutting bench, downdraft on a flat polishing table, side-draught on a drill press, full enclosure on a sandblast cabinet.

Trunk duct transport velocity 18-22 m/s minimum to keep respirable silica entrained. Below 15 m/s and the silica drops out, builds up inside the duct and starts to choke the system. Above 25 m/s and pressure drop becomes uneconomic. The SBAL-V fabricates the trunk duct at 1.0-1.2 mm galvanised on Pittsburgh seam — heavier than standard 0.7 mm office-grade duct because silica-loaded airflow abrades through 0.7 mm in three to five years. Hood transitions in 1.0-1.2 mm galvanised, mains in 0.7-1.0 mm.

Filtration train — cyclone, bag filter, HEPA polish

The silica capture filtration train runs in three stages. Stage one is a high-efficiency cyclone pre-separator that removes coarse fragments and chips above 50 microns at typically 85-95 percent efficiency. Stage two is a pulse-jet bag filter with PTFE membrane media at 1.0-1.5 m/min air-to-cloth ratio for the respirable silica fraction at 99.9 percent efficiency below 1 micron. Stage three (optional but recommended for plants targeting personal exposure below 0.025 mg/m3) is a HEPA H13 polish filter that catches any breakthrough particulate at 99.95 percent at 0.3 micron.

Bag filter design references AS 4655 fire safety in waste recycling for the housing fire protection. Hopper isolation valve isolates the baghouse from the upstream process during filter changeout. Collected silica returned to glass cullet stream or disposed as inert waste depending on the facility's recycling scheme.

Personal monitoring

AS 3640 covers personal monitoring methodology. Workers at cutting benches, edge grinders, drill presses and sandblast cabinets wear personal sampling pumps for an 8-hour shift, sampling onto pre-weighed PVC filters through a respirable-fraction cyclone sampler at 1.7-2.2 L/min. Filters are gravimetrically analysed and the silica fraction quantified by X-ray diffraction or FTIR. Baseline survey on commencement, then at least annually for any worker in a silica-exposure role. Record retention 30 years per Safe Work Australia silicosis health monitoring requirements.

SBKJ machinery scope for cutting and edge grinding HVAC

Almost all cutting and edge grinding HVAC duct is within SBKJ machinery scope. The SBAL-V fabricates rectangular duct at 0.5-1.5 mm galvanised on Pittsburgh seam, the SBTF-1500C or SBTF-1602 fabricates spiral round mains at 80-1500 mm or 80-1600 mm diameter respectively, the SBTF-2020 covers large-span 2000 mm diameter cullet conveyor exhaust, the SBHF ovalizer transitions round to flat-oval for low-headroom runs above cutting benches, the SBEM-1250 elbow former produces 90-degree and 45-degree elbows for transitions, the SBSF-1525 hydraulic shear at 2.5 kW cuts coil and plate up to 1525 mm wide, the SBFB-1500 cleat folder at 7.5 kW and 1.20 m/min folds TDF flanges and Pittsburgh seam locks, and the SBPC1500 plasma cutting line cuts custom hood transitions in stainless and heavy galvanised plate. Single-shift output of a complete SBAL-V plus SBTF plus SBFB-1500 cell is 250-400 lineal metres of duct.

Tempering furnace heat extraction — the heaviest scope item

Glass tempering (also called toughening) is the thermal treatment that heats annealed glass to 600-700 degrees Celsius and rapidly cools it with compressed-air quench to lock in compressive surface stress. Tempered glass is four to five times stronger than annealed glass and shatters into small blunt fragments on failure — the basis of AS 2208 Grade A safety glass classification. Tempering is mandatory for shower screens, balustrades, frameless doors, oven doors and most architectural glazing.

Furnace operation

A tempering furnace is a horizontal roller-hearth furnace with electric resistance heating elements above and below the glass. Glass loads onto ceramic-fibre rollers, conveys through the heating zone at 30-90 seconds residence time (depending on thickness), exits into the quench station where high-pressure air at 8-12 bar blasts the glass surface to lock in the toughening. Furnace internal temperature 600-700 degrees Celsius continuous; ambient air around the furnace can reach 50-60 degrees Celsius without active extraction. Quench air supply is filtered, dehumidified compressed air at 4-5 m3/min per kg of glass.

Heat extraction — roof exhaust hood

The tempering furnace generates a substantial radiant heat plume above the furnace roof and at the loading and unloading ends. A roof exhaust hood positioned above the furnace captures the plume at 1.5-2.0 m/s face velocity. Hood material is the critical specification: at temperatures above 200 degrees Celsius continuous, galvanised duct loses zinc coating integrity and starts to flake; at temperatures above 350 degrees Celsius, even 304 stainless will discolour and develop chromium carbide precipitation that compromises long-term corrosion resistance.

SBKJ specification for tempering furnace roof exhaust hood: 1.5-2.5 mm welded mild steel or 304L stainless for the immediate hood and short transition main (outside SBAL-V scope, fed by SBKJ duct welding line at 1.6 mm or subcontracted heavy-gauge if material is thicker). Downstream of a cooldown header where ambient air dilution drops exhaust temperature below 400 degrees Celsius, the duct transitions to 1.0-1.5 mm 304L on the SBAL-V. Below 200 degrees Celsius, the duct transitions to galvanised on the SBAL-V. Total heat extraction duct length for a typical tempering line 60-120 lineal metres of mixed material.

Quench station supply air

The quench station immediately downstream of the heating zone blasts the glass surface with compressed air at 8-12 bar to lock in the toughening. Supply air comes from an air dryer plant room running screw or rotary compressors, refrigerant dryer and desiccant polish to deliver dew point below -40 degrees Celsius and oil content below 0.01 mg/m3. The compressed-air delivery to the quench station is through stainless or galvanised piping (outside HVAC scope — sits in process piping AS 4041); the supply air for the air dryer plant room itself is HVAC scope, typically 6-8 ACH cooling supply through SBAL-V galvanised duct.

NFPA 86 compliance

Tempering furnace exhaust train sits within NFPA 86 industrial furnace ventilation scope. Purge volume calculation per NFPA 86 Chapter 8 — typically four furnace volumes of fresh air change before furnace start-up to remove residual combustible. Combustion-safety interlocks on the burner train, exhaust fan run-on after furnace shutdown, exhaust stack height and dispersion per NFPA 86 and local council planning approval. Australian operators run NFPA 86 in parallel with AS 4041 piping code and AS 1228 boiler code.

EN 12150 and EN 14179 — heat soak test

Toughened glass produced to EN 12150 (or AS 2208 Grade A) may contain nickel sulfide inclusions that cause spontaneous breakage years after installation. The EN 14179 heat soak test holds the toughened glass at 290 degrees Celsius for 2 hours after toughening to identify and destroy units with nickel sulfide inclusions before they leave the factory. The heat soak chamber is a separate piece of equipment downstream of the tempering furnace, with its own NFPA 86 exhaust train and HVAC envelope.

Laminating bay and autoclave HVAC — the clean room cousin

Laminated glass is two or more glass panes bonded together with a polymer interlayer — typically PVB (polyvinyl butyral), EVA (ethylene vinyl acetate) or SentryGlas. Laminated glass is mandatory for overhead glazing per AS 1288, for balustrades above a certain height, for automotive windshields and for many architectural applications where post-failure containment matters. ISO 12543 governs the product specification.

Process flow

Laminating runs in three steps. Step one — assembly: cut and edge-polished glass panes are washed, dried and assembled with the interlayer film on a clean assembly table. Step two — pre-press: the assembled stack passes through nip rollers at 60-90 degrees Celsius and low pressure to consolidate the interlayer and remove most of the air. Step three — autoclave: the consolidated stack enters the autoclave at 140 degrees Celsius and 12 bar for 2-3 hours to fully bond the interlayer.

Assembly bay clean room HVAC

The assembly bay is functionally a clean room — any dust trapped between the glass and the interlayer during assembly is permanently visible after lamination and the unit is scrapped. SBKJ specifies HEPA-filtered supply at 12-15 air changes per hour, 20-22 degrees Celsius ambient, 30-40 percent relative humidity, positive pressure 12-15 Pa to surrounding zones, low-velocity diffusers (terminal velocity 0.45 m/s) above the assembly tables. Operators wear lint-free coveralls, gloves and hairnets. Floor and wall surfaces washable and non-shedding.

Material selection: galvanised G300 Z275 on the SBAL-V for the supply duct from the AHU to the HEPA terminal housings, with smooth interior finish and sealed Pittsburgh seams. SBKJ duct welding line provides longitudinal welded seam where leak-class A air-tightness is specified. Return air through the floor or wall returns into SBTF spiral round mains back to the AHU. The HEPA terminal housings themselves are typically OEM components fitted into the SBAL-V supply ducting through SBPC1500-cut custom transition panels.

Autoclave room HVAC

The autoclave is a sealed pressure vessel — once the door is closed and the cycle starts, the only HVAC requirement is heat rejection at the autoclave outer wall and emergency venting for compressed-air release on a fault. Autoclave room general dilution at 4-6 ACH through SBAL-V galvanised supply and return. Emergency venting interlocked to the compressed-air control system; on a high-pressure alarm, the autoclave room exhaust ramps up to provide rapid dilution of any released gas (typically air at 12 bar, but autoclaves running with nitrogen blanket need higher dilution rates).

Autoclave outer wall surface temperature can reach 60 degrees Celsius during the cycle, providing a continuous radiant heat load on the surrounding room. Personnel comfort 24-26 degrees Celsius at the operator station; if the autoclave is large or the room is small, additional spot cooling may be specified through insulated SBAL-V galvanised supply duct delivered at 4-metre spacing along the room perimeter.

SBKJ machinery scope for laminating

The laminating bay is largely SBAL-V scope — galvanised supply and return duct, sealed Pittsburgh seams or welded longitudinal seams to leak-class A, SBTF spiral return mains, SBHF flat-oval transitions for low-headroom runs above the assembly tables. The autoclave room is also SBAL-V scope. The autoclave itself is OEM equipment outside the HVAC duct scope, but the autoclave compressed-air feed lines, steam supply (if heated by steam rather than electric) and condensate return are process piping that the mechanical services contractor handles in parallel with the HVAC ductwork.

Mirror coating cleanroom and back paint extract

Mirror manufacturing splits into two production routes. Wet silvering — the traditional process — uses ammoniacal silver nitrate solution to deposit silver onto a clean glass surface, followed by a copper protective layer and a back paint to seal the coating. PVD sputter coating — the modern process — uses physical vapour deposition in a vacuum chamber to deposit silver, aluminium or a multilayer low-emissivity stack onto the glass surface. Both routes have distinct HVAC requirements.

Wet silvering HVAC

Wet silvering is the classic mirror manufacturing process. Glass enters the silvering line through a wash and sensitisation stage (typically tin chloride), then passes under spray heads that apply ammoniacal silver nitrate and a reducing agent (typically Rochelle salt or sodium hydroxide-glucose), then under copper sulphate spray for the protective layer, then through a drying oven and a back paint application.

The HVAC challenge in wet silvering is ammonia extract. Silver nitrate is dissolved in ammonia solution and the spray application liberates ammonia vapour at the spray head. AS/NZS 1668.2 Section 6 and Safe Work Australia ammonia workplace exposure standard 25 ppm 8-hour TWA, 35 ppm STEL drive the extract design. Spray hood face velocity 0.4-0.6 m/s capturing the ammonia plume into 304L stainless duct (SBAL-V scope at 1.0-1.5 mm) routed to a packed-tower scrubber with sulphuric acid neutralisation. Hood material 304L stainless because galvanised will corrode within months from ammonia and silver-nitrate splash.

Downstream of the silver and copper coating, the glass passes through a drying oven at 80-120 degrees Celsius. Oven exhaust 304L stainless on the SBAL-V, vented through a roof stack or routed back to the ammonia scrubber depending on residual ammonia content. Personnel HVAC for the wet silvering line through galvanised SBAL-V supply at 22-24 degrees Celsius, 8-10 ACH, with Class III filtration on the supply to keep dust off the freshly silvered surface.

PVD sputter coating HVAC

PVD sputter coating runs the glass through a series of vacuum chambers where silver, aluminium or a multilayer low-emissivity stack is sputtered onto the surface from solid targets bombarded by argon ions. The sputter chamber itself is a sealed vacuum environment that does not need general HVAC. The load-lock and transport zones between chambers, however, run at atmospheric pressure under controlled cleanroom conditions to prevent particulate contamination of the optical surface.

SBKJ specification for the sputter coating cleanroom shell: ISO 14644 Class 7-8 in the load-lock and transport zones at 22-24 degrees Celsius, 45-55 percent relative humidity, positive pressure 12-25 Pa to surrounding zones, 30-60 ACH through HEPA H13 terminal housings, downflow at 0.45 m/s. Galvanised G300 Z275 on the SBAL-V at 0.6-1.0 mm with sealed Pittsburgh seams for the cleanroom shell ducting. SBKJ duct welding line provides longitudinal welded seam to leak-class A air-tightness for the HEPA supply mains.

Argon supply for the sputter chambers is bottled or bulk-tank gas delivered through dedicated process piping (outside HVAC scope). Sputter chamber pump-down vents go to atmosphere through dedicated exhaust stacks; the small argon and target-material release does not require scrubbing in most installations.

Mirror back paint VOC extract

Mirror back paint is applied after silvering and copper coating to seal the mirror surface and provide mechanical protection. Traditional back paints are alkyd-based with mineral spirits solvent; modern back paints are increasingly water-based or low-VOC alkyd. The back paint application is typically a roll-coater, curtain-coater or spray booth followed by a drying oven at 60-80 degrees Celsius.

NFPA 33 Standard for Spray Application Using Flammable or Combustible Materials governs the spray booth design if solvent-based paint is used. AS/NZS 1668.2 Section 6 covers paint spray booth ventilation in the Australian framework. Cross-draught or down-draught booth construction with 0.4-0.6 m/s face velocity at the operator plane, recovery filter for paint overspray, HEPA secondary filter before discharge. Booth wall and plenum construction in galvanised SBAL-V (the airstream is dry paint mist, not corrosive vapour) with stainless transitions where solvent vapour concentration is high.

Drying oven exhaust at 60-80 degrees Celsius runs galvanised SBAL-V if the VOC capture is upstream of the oven; 304L stainless if VOC capture is at the oven exit. VOC abatement train is typically activated carbon for low VOC load (modern water-based paint) or thermal oxidiser for high VOC load (traditional alkyd). Discharge through a roof stack per state EPA licence and local council planning approval.

Cleanroom HVAC vs general factory air

The mirror coating cleanroom is the only true cleanroom in most Australian glass plants. The cleanroom shell is segregated from the surrounding factory by full-height partitions, airlocks at every personnel and material entry, and positive pressure 12-25 Pa to the surrounding factory. Cleanroom HVAC is dedicated — its own AHU, HEPA terminal housings, supply ducting and return air paths. Surrounding factory air comes nowhere near the cleanroom supply path.

Crystal Mirror NSW and several smaller Australian mirror manufacturers run wet silvering rather than sputter coating because of the smaller capital cost. The HVAC scope for wet silvering is mostly SBAL-V (galvanised supply and return) with 304L stainless on the ammonia extract. PVD sputter coating is rarer in Australia; the larger Australian mirror manufacturers and the architectural low-E glass processors (Cardinal IG Australia, Viridian for the SuperGreen low-E product) source coated glass from offshore PVD lines and run downstream cutting, edge grinding and IGU assembly locally.

Insulating glass unit (IGU) assembly

Insulating glass units (IGUs) are double-glazed or triple-glazed units with a gas-filled cavity between glass panes, sealed at the edge with a butyl primary seal and a silicone, polysulphide or polyurethane secondary seal. AS 4666 governs the product specification. The Australian IGU market is dominated by Viridian, G.James, Cardinal IG, Australian Glass Group, Metro Performance Glass NZ and dozens of regional fenestration fabricators.

IGU assembly clean room HVAC

IGU assembly is functionally a clean room — any dust trapped between the glass panes during assembly is permanently visible after sealing and the unit is scrapped. More critically, any moisture in the cavity at sealing saturates the desiccant before the unit is in service, causing condensation between panes within six months. SBKJ specifies HEPA-filtered supply at 12-18 ACH, 20-22 degrees Celsius ambient, room dew point below 10 degrees Celsius (typically 30-40 percent relative humidity at 20 degrees Celsius), positive pressure 12-15 Pa to surrounding zones, low-velocity diffusers above the assembly tables.

Galvanised G300 Z275 on the SBAL-V for supply and return. Sealed Pittsburgh seams or welded longitudinal seams to leak-class A air-tightness. SBTF spiral round return mains back to the AHU. SBHF flat-oval transitions for low-headroom runs above assembly tables where ceiling clearance is limited.

Desiccant filling extract

The aluminium or warm-edge polymer spacer bar is filled with molecular sieve desiccant before the IGU is assembled. The filling operation generates fine desiccant dust at the filling port. Local exhaust capture at 0.5-0.7 m/s face velocity into a small bag filter, discharged back to the cleanroom return after particulate removal. Galvanised SBAL-V scope.

Gas filling — argon and krypton

Insulating glass units are gas-filled with argon (typical), krypton (premium triple-glazed) or xenon (rare specialty). The gas fills the cavity between panes through a small port that is then sealed. Argon and krypton are inert and not toxic but are denser than air and can accumulate in low-lying spaces if released in volume. The cleanroom HVAC has to include gas-leak monitors at floor level and an emergency exhaust ramp-up interlocked to the gas detection system. SBAL-V galvanised supply, SBTF spiral return.

Sealant station extract

The IGU sealing station applies the butyl primary seal (typically as a hot-melt extrusion) and the silicone, polysulphide or polyurethane secondary seal. The butyl extrusion at 120-150 degrees Celsius releases small amounts of plasticiser vapour; the silicone or polysulphide cure releases minor acetic acid (silicone) or sulphide odour (polysulphide). Local exhaust capture at 0.5-0.7 m/s face velocity into 304L stainless duct (SBAL-V scope) routed to an activated carbon bed before discharge.

Decorative glass acid etching and sandblasting

Decorative glass — frosted glass, patterned glass, custom-etched architectural panels — is a specialty segment that demands the most rigorous HVAC specification in the entire glass plant landscape. The two main decorative processes are acid etching with hydrofluoric acid and sandblasting with aluminium oxide or garnet abrasive. Smart Decorative Glass, Crystal Mirror, Schweitzer Glass, Custom Glass Solutions and several smaller specialist operators run decorative glass production in Australia.

HF acid etching — the highest-stakes scope item

Hydrofluoric acid (HF) is one of the most dangerous chemicals in routine industrial use. Skin contact with concentrated HF causes deep tissue burns with delayed onset; HF absorbs through skin and chelates calcium in deep tissue. Inhalation of HF vapour at concentrations above 30 ppm is immediately dangerous to life and health. AS 4775 emergency eyewash and shower equipment is mandatory at every HF workstation, and the eyewash must deliver calcium gluconate gel for emergency neutralisation alongside standard tepid water.

HF acid etching uses concentrated HF (typically 40-50 percent) or ammonium bifluoride paste applied to the glass surface. The acid attacks the silica matrix of the glass and creates a frosted or patterned finish. The exhaust train captures HF vapour from the tank or paste application station at 0.5-0.7 m/s face velocity into 304L stainless duct (SBAL-V scope at 1.0-1.5 mm) routed direct to a packed-tower wet scrubber with calcium hydroxide (lime) neutralisation.

Material selection is non-negotiable. HF attacks galvanised duct within weeks (zinc fluoride formation and zinc loss), attacks 304 stainless within months (chromium fluoride formation with surface pitting) and degrades 316L over years (slower but still detectable). For high-volume HF etching lines, the duct material upgrades to FRP (fibreglass-reinforced plastic) which has excellent HF resistance but sits outside SBKJ machinery scope — fabricated by hand lay-up or filament winding at specialist composite shops. For low to medium volume, 304L stainless with TIG-welded seams everywhere is the SBKJ specification, with planned replacement every 5-7 years rather than the 25-year design life of standard galvanised.

Sandblasting HVAC

Sandblasting uses compressed-air-driven aluminium oxide or garnet abrasive to physically erode the glass surface, producing a frosted or patterned finish. The cabinet enclosure captures the abrasive and the eroded glass dust at full enclosure construction. Cabinet exhaust into a cyclone pre-separator (recovers the abrasive for reuse) then a pulse-jet bag filter (captures the respirable silica fraction from the eroded glass). The exhaust is silica-loaded — same engineering controls as the cutting bench dust capture covered above. SBAL-V galvanised at 1.0-1.2 mm for the trunk duct, SBTF spiral mains, SBPC1500 plasma-cut hood transitions.

Decorative paint and printing

Some decorative glass is back-painted or silk-screen printed for architectural panel applications. The paint and ink processes follow the mirror back paint VOC capture pattern: cross-draught or down-draught booth, recovery filter for overspray, activated carbon or thermal oxidiser for VOC abatement before discharge. Galvanised SBAL-V on booth walls and plenum, 304L stainless transitions where solvent vapour concentration is high.

Container glass plant HVAC — IS machine and lehr

Container glass production runs the heaviest single HVAC duct length of any glass plant type. O-I Glass Australia at Penrith NSW operates Australia's largest container glass plant, producing wine bottles, beer bottles, spirits bottles, food jars and pharmaceutical containers. The plant runs regenerative furnaces at 1500-1600 degrees Celsius melt temperature, gob distribution at 1100-1200 degrees Celsius forming, Individual Section (IS) machines at 100-300 containers per minute per section, annealing lehrs at 540 degrees Celsius inlet down to 100 degrees Celsius outlet, cold-end inspection, decoration and packaging. Each zone is a distinct HVAC scope item.

Batch house silica capture

The batch house receives silica sand, soda ash, limestone, dolomite, feldspar, salt cake and recycled cullet, weighs them by recipe and conveys to the furnace charging end. Every transfer point — bag dump, hopper transfer, conveyor handover, mixer charge, mixer discharge — generates a silica dust plume. Source-capture local exhaust hoods at every transfer, transport velocity 18-22 m/s in 1.0-1.2 mm galvanised SBAL-V duct, baghouse with PTFE membrane media. Personnel zone HVAC at 24-26 degrees Celsius with positive pressure 12-25 Pa to the surrounding batch house through Class III filtration.

Furnace ambient HVAC

The regenerative or recuperative furnace is the heart of the plant. Combustion exhaust at 350-450 degrees Celsius through the regenerator stack is heavy-gauge welded mild steel or refractory-lined plate — outside SBKJ machinery scope. Personnel-zone ambient HVAC around the furnace — hot-end operator pulpit at 26-28 degrees Celsius refrigerated supply, electrical room at 22-24 degrees Celsius positive pressure, maintenance corridor at 10-12 ACH general ventilation — sits within SBAL-V galvanised scope.

IS machine area HVAC

The Individual Section (IS) machine is the workhorse of container glass production. Six to twelve sections each running blow-and-blow or press-and-blow forming. Radiant heat from gobs at 1100-1200 degrees Celsius plus furnace charging end proximity pushes ambient to 40-50 degrees Celsius without active cooling. Operator pulpit at 26-28 degrees Celsius through 8-12 ACH refrigerated supply via insulated SBAL-V galvanised supply duct with internal liner.

Each IS section runs a swabbing routine where a graphite-based mould lubricant is applied every 4-8 hours. The atomised lubricant generates an oil mist that is captured at the source through a 304L stainless local exhaust hood at 1.0-1.5 m/s face velocity, conveyed in 304L SBAL-V duct to a dedicated mist eliminator and roof stack.

Annealing lehr corridor HVAC

The annealing lehr is a slow-cooling tunnel oven from 540 degrees Celsius inlet down to 100 degrees Celsius outlet over 60-90 minutes residence. Lehr stack exhaust is welded mild steel — outside SBKJ scope. Lehr corridor personnel HVAC at 30 degrees Celsius maximum ambient through 6-8 ACH ventilation in galvanised SBAL-V supply duct, SBTF spiral round return mains.

Cold-end stearate coating exhaust

At the lehr exit, container glass receives a cold-end stearate slip coating to reduce friction on the conveyor. Stearate coating exhaust capture at 1.0-1.5 m/s face velocity into 304L stainless duct (SBAL-V scope at 1.0-1.2 mm) to a HEPA-grade pre-filter and activated carbon bed for VOC compliance. Galvanised will not survive the organic-acid breakdown products of stearate residues for more than 12-18 months.

Decoration and bake oven

Container glass decoration — silk-screen printing, enamel coating, fluoropolymer coating — uses solvent-based or water-based inks and paints. Spray booth construction in galvanised SBAL-V plenum walls with 0.4-0.6 m/s face velocity. Bake oven exhaust at 400-500 degrees Celsius (for enamel fusing) uses 1.5 mm welded mild steel — outside SBKJ machinery scope.

Automotive glass and windshield production

Automotive glass production runs cut-and-shaped flat glass through bending, tempering, laminating and silvering operations to produce windshields, side and rear windows, sunroofs and mirror assemblies. Saint-Gobain Australia (Sekurit) and Pilkington Australia (NSG) operate Australian automotive glass processing primarily for the aftermarket replacement market. The Australian original equipment vehicle (OEM) market is small after Toyota and Ford ceased Australian assembly, but the aftermarket replacement market is substantial through SafetyGlass Australia, Novus, O'Brien Glass and other replacement suppliers.

Bending furnace HVAC

Automotive windshields and rear windows are bent to compound curvature through a gravity sag or roller-hearth bending furnace at 600-650 degrees Celsius. Bending furnace HVAC scope mirrors the tempering furnace pattern: roof exhaust hood at 1.5-2.5 mm welded mild steel or 304L stainless (outside SBAL-V, fed by SBKJ duct welding line at 1.6 mm), downstream cooldown transition to 1.0-1.5 mm 304L on the SBAL-V, then galvanised below 200 degrees Celsius.

Windshield laminating

Automotive windshields are laminated glass with a PVB interlayer designed for impact penetration resistance per ISO 12543 and AS 2208 Grade A. The laminating assembly bay is a clean room — 12-15 ACH HEPA-filtered supply, 20-22 degrees Celsius, 30-40 percent relative humidity, positive pressure 12-15 Pa. Galvanised SBAL-V scope for the cleanroom shell, 304L stainless on the autoclave room emergency vent extract.

Side window tempering

Automotive side and rear windows are tempered glass per AS 2208 Grade A safety classification. Tempering line HVAC scope matches the architectural tempering pattern covered above — 1.5-2.5 mm welded mild steel on the roof exhaust, transitioning to 304L SBAL-V downstream of a cooldown header.

Headlamp lens and mirror coating

Automotive headlamp lenses (polycarbonate, not glass — outside this guide) and automotive mirror assemblies are processed through small-volume operations. The mirror coating for automotive applications is typically the same wet silvering or PVD sputter pattern as architectural mirror coating, scaled down for the smaller automotive mirror surface area.

Cullet handling dust extraction and fire risk

Cullet — recycled glass — is the largest single ingredient in modern container glass batch by weight, often 30-70 percent of the batch. Visy Glass Recycling, integrated with O-I container operations from 2024, operates Australia's largest cullet processing footprint at Smithfield NSW (Sydney), Wacol QLD (Brisbane) and Reservoir VIC (Melbourne). Architectural glass plants (Viridian, G.James) also recycle cullet from cutting and edge-grinding offcuts back into supply chain.

Crushing and screening dust extraction

Cullet crushing reduces bottle glass to chips and fine particles. Every crusher, screen and conveyor transfer generates dust — a mix of respirable silica from the broken glass and organic dust from any residue (label paper, plastic closures, food contamination). Local exhaust capture at every crusher and screen, transport velocity 18-22 m/s minimum in 1.0-1.2 mm galvanised SBAL-V duct, baghouse with PTFE membrane media. The SBTF-2020 large-diameter spiral pipe at 2000 mm covers the long-span return-air mains and the cullet conveyor enclosure exhaust.

NFPA 654 combustible dust review

Cullet contaminated with organic residue falls within NFPA 654 (and the new NFPA 660 consolidated dust standard) scope at dust layer thickness above 0.4 mm. Engineering controls required: explosion vents on the cullet baghouse hopper sized per NFPA 68, isolation valves between dust collector and process equipment, electrostatic grounding on all duct and equipment, documented dust hazard analysis. Hopper design with smooth surfaces, no horizontal ledges where dust can accumulate, and accessible cleaning panels for routine housekeeping.

Lithium-ion battery contamination — the emerging fire risk

Small lithium-ion batteries (vape devices, hearing aids, button cells) inadvertently entering glass recycling streams alongside bottle glass have caused multiple cullet plant fires globally since 2022. A single damaged Li-ion cell in a cullet crusher can release thermal energy sufficient to ignite organic dust above the cullet stream, propagating fire through the conveyor system into the baghouse.

HVAC implications: cullet processing zones now require fire detection (infrared spot detectors and continuous CO monitoring) integrated with the dust collection system, automatic dampering to isolate the baghouse on fire signal, and explosion venting on the baghouse hopper per NFPA 654. Duct material on cullet-processing source-capture mains may upgrade from standard galvanised to galvanised with intumescent fire-rated coating where insurance requirements demand. AS 1530.4-tested fire dampers at every duct penetration through a fire-rated wall.

Optical sorting and magnetic separation

Modern cullet processing includes optical sorting (camera-based colour separation of flint, amber and green glass) and magnetic separation (removes ferrous contamination from bottle caps and closures). Both processes are housed in enclosed sorting cabins with local exhaust capture at 0.5-1.0 m/s face velocity to keep dust off the optical sensors and out of the operator zone. Galvanised SBAL-V scope.

Spray glass coating and low-E sputter

Low-emissivity (low-E) coatings reduce solar heat gain and improve thermal insulation in architectural glazing. Two coating routes dominate: offline PVD sputter (the architectural low-E approach used by Cardinal IG LoE2-272, LoE3-366, Viridian SuperGreen and similar premium products) and online pyrolytic (the chemical vapour deposition approach applied at the float bath tin side, used by Pilkington K Glass and similar).

Offline PVD sputter coating

Offline PVD sputter coating runs cut flat glass through a series of vacuum chambers where multilayer low-E coatings (silver, silver-nitride, indium-tin oxide, zinc oxide, titanium oxide combinations) are sputtered onto the surface. The HVAC envelope is the same ISO 14644 Class 7-8 cleanroom pattern described in the mirror coating section above. The sputter chambers themselves are sealed vacuum environments not requiring general HVAC; the load-lock and transport zones require cleanroom-grade air.

Galvanised G300 Z275 on the SBAL-V at 0.6-1.0 mm for the cleanroom shell ducting. SBKJ duct welding line provides longitudinal welded seam to leak-class A air-tightness for the HEPA supply mains. SBTF spiral round return mains. SBHF flat-oval transitions for low-headroom runs.

Online pyrolytic coating

Online pyrolytic coating applies the low-E coating during the float glass forming process, at the tin side of the float bath where glass temperature is 600-700 degrees Celsius. The CVD precursor (typically tin tetrachloride or organotin) is sprayed onto the hot glass and reacts at the surface to deposit a tin oxide or fluorine-doped tin oxide coating. Australia does not run a float line domestically, so online pyrolytic coating is outside the typical Australian HVAC scope — but Australian operators do specify online pyrolytic K Glass and similar imported through Pilkington supply chains.

Materials selection for glass and mirror plant HVAC duct

Material selection drives both initial cost and lifecycle cost. Glass and mirror plant HVAC duct sees five main material classes. Specifying the wrong material on any one of them turns a 25-year design life into a 12-month replacement project.

Galvanised G300 Z275

Galvanised G300 sheet with Z275 zinc coating (275 g/m2 total both sides per AS 1397) is the workhorse material for general HVAC in glass and mirror plants. Acceptable for: personnel-zone supply and return, factory floor dilution, IGU clean room shell, laminating bay clean room shell, mirror coating cleanroom shell, cutting and edge grinding source-capture mains, cullet conveyor enclosure exhaust, container glass batch house personnel zone, IS machine operator pulpit supply, lehr corridor, automotive bending furnace downstream of cooldown header (below 200 degrees Celsius), packaging area HVAC, control rooms, electrical rooms, admin and laboratory zones. Limited to 80 degrees Celsius continuous service temperature, with short-duration excursions to 200 degrees Celsius acceptable. Not suitable for HF acid etch, mirror back paint VOC, ammonia mirror silvering, sustained high-temperature furnace exhaust or chloride-exposed coastal float plant returns.

Forms readily on the SBAL-V (0.5-1.5 mm), SBAL-III (0.5-1.2 mm) and SBAL-II (0.5-1.2 mm) auto duct lines. SBTF-1500C, SBTF-1602 and SBTF-2020 form spiral round at 80-2000 mm diameter in galvanised. SBFB-1500 cleat folder forms TDF flanges. SBSF-1525 hydraulic shear cuts coil and plate. SBEM-1250 elbow former produces transitions. SBHF ovalizer transforms round to flat-oval. SBPC1500 plasma cutting line cuts custom hood transitions. The full SBKJ machinery range is configured for galvanised as the default material.

304L stainless

304L stainless (austenitic chromium-nickel grade with low carbon for welded fabrication) is the default upgrade material for any glass plant duct service that exceeds galvanised limits. Specify for: mirror back paint VOC extract, mirror wet silvering ammonia extract, mirror drying oven exhaust, container glass cold-end stearate coating exhaust, IS machine swabbing oil mist exhaust, sustained tempering furnace exhaust below 400 degrees Celsius, decorative glass acid etching exhaust (low to medium volume HF; FRP for high volume), wet silvering line drying oven, laminating bay HEPA terminal housing transitions where leak-class A air-tightness is specified.

Forms readily on the SBAL-V at 0.6-1.5 mm with 30-minute mode changeover from galvanised. SBAL-III handles 304L at 0.6-1.2 mm. SBTF-1500C and SBTF-1602 wind 304L spiral round at 80-1500 mm or 80-1600 mm. SBKJ duct welding line provides longitudinal welded seam at 0.6-1.6 mm for leak-class A air-tightness on stainless seams.

316L stainless

316L stainless (austenitic chromium-nickel-molybdenum grade with low carbon) adds molybdenum content for chloride resistance compared to 304L. Specify for: coastal float plant returns where salt aerosol contamination from sea air drives chloride pitting on standard 304L, ion-exchange chemical strengthening rooms (potassium nitrate bath at 380-420 degrees Celsius releases nitrate aerosols), anodised aluminium decorative-mirror processing lines where chloride contamination of the anodising bath is present, high-volume HF acid etching where 304L lifecycle is too short.

Forms on the SBAL-V at 0.6-1.5 mm with 30-minute mode changeover. Premium material cost approximately 30 percent over 304L; specify only where chloride or HF exposure justifies the upgrade.

Fibreglass-reinforced plastic (FRP)

FRP duct — typically hand lay-up vinyl ester or epoxy resin with E-glass reinforcement — is the specialist material for high-volume HF acid etching extract, chloride-aerosol-exposed runs where even 316L lifecycle is uneconomic, and very corrosive process exhaust outside the scope of stainless. FRP has excellent corrosion resistance, low thermal conductivity (no condensation on outer surface), low weight (one-third the weight of equivalent stainless) and acceptable strength on properly designed flange systems.

FRP sits outside SBKJ machinery scope — fabricated by hand lay-up or filament winding at specialist composite shops. Where an Australian glass plant project requires FRP duct, the mechanical services contractor subcontracts the FRP portion to a composite fabricator and supplies the surrounding galvanised, 304L or 316L from the SBKJ machinery shop. The interface between FRP and metal duct is a flanged transition with elastomer gasket, not a welded or seamed joint.

Mild steel (welded heavy gauge)

Mild steel at 1.5-2.5 mm thickness with welded fabrication is the material for high-temperature tempering furnace roof exhaust, annealing lehr stack exhaust, container glass regenerative furnace stack exhaust, container glass decoration bake oven exhaust (400-500 degrees Celsius), automotive bending furnace immediate exit collar. The SBKJ duct welding line welds longitudinal seam at 0.6-1.6 mm — covering the lower end of this range. Above 1.6 mm material thickness, fabrication moves to plate rolling and submerged-arc welding shops with ASME Section IX qualified procedures.

Refractory-lined construction may be specified where exhaust temperatures exceed 600 degrees Celsius continuous — sits firmly outside any sheet metal duct machinery scope.

SBKJ machinery scope for glass and mirror plant HVAC duct fabrication

The realistic procurement question for a mechanical services contractor or in-house plant engineer building a duct fabrication capability to serve Australian glass and mirror plants is: which SBKJ machines do I need, and what does each one cover? The answer maps to the line speeds, gauges and capacities verified on each SBKJ model.

SBAL-V — the workhorse auto duct production line

The SBAL-V auto duct production line is the flagship SBKJ duct machine. Line speed 16 m/min, installed motor power 87 kW, sheet thickness 0.5-1.5 mm, coil width up to 1500 mm. Dual-mode galvanised and 304L stainless on a single line with 30-minute mode changeover. Produces rectangular duct from 200x100 mm to 1500x1500 mm with Pittsburgh seam, TDF flange forming, beading and notching in one pass. Single-shift output 250-400 lineal metres on standard configuration.

SBAL-V scope in a glass and mirror plant: cutting and edge grinding silica capture mains, mirror coating cleanroom shell, laminating bay HEPA terminal supply mains, IGU assembly cleanroom supply and return, decorative glass operator pulpit supply, container glass IS machine operator pulpit supply, lehr corridor HVAC, batch house personnel zone, automotive bending furnace downstream of cooldown header, packaging area, control rooms, admin and laboratory. Approximately 65-70 percent of total HVAC duct length in a typical glass and mirror plant.

SBAL-III — mid-capacity auto duct line

The SBAL-III auto duct production line is the mid-capacity SBKJ duct machine. Line speed 14 m/min, installed motor power 15.7 kW, sheet thickness 0.5-1.2 mm, coil width up to 1500 mm. Single-mode galvanised typically, with optional stainless capability. Suits mid-sized regional glass processors and mechanical services contractors handling one architectural glass project at a time. Single-shift output 200-300 lineal metres.

SBAL-II — compact auto duct line

The SBAL-II auto duct production line is the compact-footprint SBKJ duct machine. Line speed 18 m/min (high speed at the limited gauge range), installed motor power 5.5 kW, sheet thickness 0.5-1.2 mm. Small footprint suits urban fabrication cells, retrofit jobs at suburban glass and mirror workshops, on-site mobile fabrication for shutdown windows where the SBAL-V is too large for the available shop space.

SBTF spiral tubeformer family

The SBTF spiral tubeformer family covers three diameter ranges. SBTF-1500C handles spiral round pipe at 80-1500 mm diameter — the standard fit for laminating bay return mains, IGU cleanroom returns and lehr corridor returns. SBTF-1602 extends to 1600 mm diameter with 1.6 mm gauge capability for the heavier silica capture mains and cullet conveyor exhaust. SBTF-2020 covers 2000 mm diameter for very long-span architectural plant exhaust, large cullet processing baghouse inlets and container glass furnace ambient HVAC.

Round spiral pipe carries 30-40 percent less material per Pa of pressure drop than rectangular equivalents at long lengths, making the SBTF the right choice for long horizontal return mains and large-diameter exhaust trunks. Approximately 15-20 percent of total HVAC duct length in a typical glass and mirror plant.

SBEM-1250 elbow former

The SBEM-1250 elbow former produces 90-degree and 45-degree elbows from coil up to 1250 mm wide for transitions between SBAL-V or SBAL-III straight duct sections. Elbow throat radius 1.0D to 1.5D selectable per AS 4254 pressure drop targets. SBEM scope is the in-line elbow fabrication that keeps the fabrication cell flowing without external elbow procurement.

SBSF-1525 hydraulic shear

The SBSF-1525 hydraulic shear at 2.5 kW installed power cuts coil and plate up to 1525 mm wide. The shear sits upstream of the SBAL-V or SBAL-III decoiler as the cut-to-length station for coil sections, and beside the SBPC1500 plasma cutting line as the secondary cutting station for galvanised and stainless plate. Shear cut produces a clean edge with no thermal heat-affected zone, important for stainless duct fabrication where edge quality drives weld quality.

SBFB-1500 cleat folder

The SBFB-1500 cleat folder at 7.5 kW installed power and 1.20 m/min folding speed forms TDF flanges, transverse flange bars and Pittsburgh seam locks on duct sections after the SBAL-V or SBAL-III straight-line forming. The cleat folder bench is the final stop before duct sections leave the fabrication cell for site delivery. See the SBFB-1500 product page for the full specification.

SBHF ovalizer

The SBHF ovalizer transforms round spiral pipe from the SBTF into flat-oval cross-section, used for low-headroom return air runs in lehr corridors and laminating bays where ceiling clearance under the overhead crane rail is tight. Flat-oval duct provides 90 percent of the pressure-drop performance of round at 70 percent of the depth, making it the right fit where vertical space is constrained.

SBPC1500 plasma cutting line

The SBPC1500 plasma cutting line cuts stainless plate and heavy galvanised plate up to 1500 mm wide for custom hood transitions on cutting bench dust capture, edge grinder local exhaust hoods, mirror back paint booth plenum panels, decorative glass HF acid etch extract hoods and any non-standard duct fitting that does not come off the SBAL-V or SBTF straight production. SBPC1500 plasma sits beside the SBAL-V in the fabrication cell as the custom-cut workstation.

SBLR-600 and SBLR-600A ring rolling lines

The SBLR-600 and SBLR-600A ring rolling lines at 7.6 m/min line speed roll round spiral pipe into reinforcement rings and stiffener bands for large-diameter SBTF-2020 mains running through cullet processing baghouse inlets and architectural plant exhaust corridors. Stiffener rings prevent ovalisation under negative pressure cycling. Specify SBLR scope on every SBTF-2020 main length exceeding 6 metres unrestrained span.

SBKJ duct welding line — pressure class D-E and leak-class A air-tightness

The SBKJ duct welding line handles longitudinal seam welding at 0.6-1.6 mm material, satisfying AS 4254 pressure class D-E (above 2500 Pa) and any leak-class A air-tightness requirement on stainless. Welding is required for: mirror coating cleanroom HEPA supply mains where leak-class A air-tightness is specified, decorative glass HF acid etch extract where every seam must be HF-tight, mirror wet silvering ammonia extract where leak-class A is specified, tempering furnace exhaust at 1.5-1.6 mm where the duct welding line covers the lower end of the heavy-gauge range, and any high-pressure batch house collection main where Pittsburgh-seam class C is below the design pressure class.

Outside SBKJ machinery scope

Three categories sit outside SBKJ standard machinery scope and require engagement of specialist welded-fabrication shops or composite fabricators. First, high-temperature tempering furnace and annealing lehr exhaust above 1.6 mm material thickness — 1.5-2.5 mm welded mild steel with plate rolling and submerged-arc welding equipment. Second, refractory-lined high-temperature exhaust above 600 degrees Celsius continuous — sits in metallurgical-fabrication territory. Third, FRP duct for high-volume HF acid etching extract — hand lay-up or filament winding at specialist composite shops.

The SBKJ engineering team helps customers plan the scope split at the quotation stage — itemising which lineal metres of the project go onto each SBKJ machine, and which go to subcontracted welded fabrication or composite. Knowing this split before signing the project contract avoids the common procurement error of buying an SBKJ line for 100 percent of the project then discovering at fit-out that 5-7 percent has to be subcontracted at a premium.

Project lead time and Australian delivery

Glass and mirror plant retrofits run on shutdown windows. Major shutdowns (4-6 weeks for furnace rebuild at O-I Penrith, 2-3 weeks for tempering line replacement at Viridian or G.James) recur every 5-12 years. Minor shutdowns (1-2 weeks) recur annually. HVAC fit-out projects are scheduled into shutdown windows and lead time discipline is critical.

SBKJ machinery lead times

Standard SBAL-V auto duct line: 60-90 days from 30 percent deposit to ex-works ready, plus 25-35 days ocean freight to Melbourne, Sydney, Brisbane, Adelaide or Fremantle. SBAL-III auto duct line: 50-75 days plus shipping. SBAL-II compact line: 45-60 days plus shipping. SBTF-1500C, SBTF-1602 and SBTF-2020 spiral tubeformers: 45-60 days plus shipping. SBEM-1250 elbow former: 30-45 days plus shipping. SBSF-1525 hydraulic shear: 30-45 days plus shipping. SBFB-1500 cleat folder: 30-45 days plus shipping. SBHF ovalizer: 45-60 days plus shipping. SBPC1500 plasma cutting line: 45-60 days plus shipping. SBLR-600 and SBLR-600A ring rolling lines: 45-60 days plus shipping. SBKJ duct welding line: 60-90 days plus shipping. Total project window from PO to commissioning is typically 16-22 weeks for a complete duct fabrication cell.

Coordination with plant shutdown windows

Viridian, Pilkington Australia, G.James, O-I Glass Australia and Saint-Gobain Australia mechanical services contractors typically order SBKJ machinery 4-6 months ahead of plant shutdown windows. The 16-22 week machine delivery and commissioning timeline is followed by 4-8 weeks of duct prefabrication in the contractor's shop before the shutdown begins. Prefabricated duct sections are packaged, trucked to the plant and installed during the shutdown clear-out and rebuild phase.

Australian shipping ports and inland delivery

SBKJ machinery routinely ships to Melbourne (general distribution, Viridian Dandenong, Pilkington Australia Dandenong), Sydney (O-I Penrith, Viridian Ingleburn, Saint-Gobain Sydney, Cardinal IG distribution), Brisbane (G.James Eagle Farm and Yatala, AGI Glass Pack), Adelaide (regional architectural glass and mirror processors) and Fremantle (Glass Industries Australia, Perth-based architectural glass). Standard 40-foot high-cube container, ISPM-15 fumigated crating, full marine all-risk insurance. Inland trucking from port to contractor's shop arranged on either CIP destination or on customer-arranged inland transport.

SBKJ Australian after-sales coverage

SBKJ Group's Australian operations at Box Hill North VIC provide English-speaking after-sales support, parts despatch and on-site service for Australian customers. Standard support package covers pre-quotation engineering review, Factory Acceptance Test (FAT) before shipment, 1-2 SBKJ engineers on site at the contractor's shop for installation and commissioning, 8-16 hours operator training and 4-8 hours maintenance training in English, one-year wear-parts kit shipped with the machine, documented spare parts lead time under 14 days for stocked items and under 45 days for build-to-order, and SBKJ continuity guarantee for spare parts on every machine model for 10+ years.

Get an itemised SBKJ quote for your glass or mirror plant duct fabrication project →

Common procurement mistakes on glass and mirror plant HVAC projects

SBKJ engineers see the same handful of procurement mistakes repeatedly on glass and mirror plant HVAC retrofits. Each one is recoverable but expensive once the project is underway. Avoiding them takes one Friday afternoon of upfront engineering review with the SBKJ Box Hill North office.

Mistake 1 — Single-mode SBAL-V instead of dual-mode

Specifying an SBAL-V configured for galvanised only forces all 304L stainless work onto subcontracted fabrication or a second machine. Glass and mirror plants need 20-25 percent of their duct in 304L (mirror back paint extract, mirror wet silvering ammonia, cold-end stearate, IS machine swabbing oil mist, decorative HF acid etch, tempering downstream cooldown). A dual-mode SBAL-V handles galvanised and 304L on the same line with a 30-minute changeover — the incremental cost of dual mode at order time is recovered on the first stainless project.

Mistake 2 — Wrong duct gauge for silica capture mains

Specifying 0.7 mm galvanised on silica capture mains because that is the standard HVAC office-building gauge. Silica-loaded airstreams abrade through 0.7 mm in three to five years; the correct specification is 1.0-1.2 mm galvanised, well within SBAL-V capability. SBAL-V handles 0.5-1.5 mm with no tooling change — there is no economic argument for under-specifying gauge.

Mistake 3 — Galvanised on HF acid etch

Saving material cost by specifying galvanised on the decorative glass HF acid etching extract. HF attacks galvanised within weeks (zinc fluoride formation). 304L stainless is the SBKJ specification for low to medium volume HF etch; FRP for high volume. The wrong material call here is a safety issue, not just a maintenance issue — corroded duct sheds particulate back into the workspace and corroded seams release HF vapour into the operator zone.

Mistake 4 — Galvanised on mirror back paint VOC extract

Specifying galvanised on the mirror back paint VOC extract because the spray booth itself is galvanised. The booth walls are galvanised — they see dry paint mist. The extract duct sees VOC at concentration, and on the back paint drying oven exhaust at 60-80 degrees Celsius the VOC concentration is high enough to attack zinc and degrade the seams. 304L stainless on the extract duct downstream of the booth is the correct specification.

Mistake 5 — Underspecified cleanroom shell air-tightness

Building the mirror coating cleanroom or laminating bay cleanroom with standard Pittsburgh-seam class C air-tightness instead of welded leak-class A. The cleanroom HEPA supply pressure ramps up over the filter life as the HEPA media loads with particulate. A class C duct flexes and unseats at high HEPA loading and the cleanroom particle count drifts out of ISO 14644 Class 7 specification. Specify welded longitudinal seam to leak-class A on every cleanroom HEPA supply main — covered by the SBKJ duct welding line at 0.6-1.6 mm.

Mistake 6 — Forgetting NFPA 654 on cullet processing

Treating cullet processing dust collection as identical to virgin batch dust collection. Cullet contains organic residue (label paper, plastic, food residue) and falls within NFPA 654 (and the new NFPA 660 consolidated dust standard) combustible-dust scope. Explosion vents on the baghouse hopper, isolation valves between the dust collector and process equipment, electrostatic grounding on all duct and equipment, and a documented dust hazard analysis are mandatory and easily forgotten at design stage. Add the lithium-ion battery contamination risk and the fire detection scope on cullet processing has expanded substantially since 2022.

Mistake 7 — No allowance for AS 1530.4 fire-rated penetrations

Designing the duct run through a fire-rated wall between two glass plant compartments without specifying the AS 1530.4-tested penetration seal. The HVAC contractor installs the duct and the building certifier rejects the install at occupancy certificate stage. Add intumescent mastic, fire-rated collars or ceramic-fibre blanket pillows to the duct specification at design stage, not at fit-out stage.

Mistake 8 — Underestimating the laminating bay clean room HVAC budget

Treating the laminating bay as a general factory zone with 6-8 ACH dilution ventilation. The laminating bay is a clean room — HEPA-filtered supply at 12-15 ACH, 20-22 degrees Celsius ambient, 30-40 percent relative humidity, positive pressure 12-15 Pa, low-velocity diffusers above the PVB layup tables. Get this wrong and the laminated glass scrap rate climbs as dust contamination becomes visible after autoclave bonding.

Mistake 9 — Wrong supply diffuser pattern in IGU assembly

Using standard ceiling diffusers blowing across the IGU sealing tables. The high-velocity supply air disturbs the spacer placement and contaminates the desiccant. Specify low-velocity diffusers (terminal velocity 0.45 m/s) directly above the sealing tables, with return air at floor level on the room perimeter. Air movement direction is from supply diffuser straight down through the work zone to the floor return — not horizontal across the work.

Mistake 10 — No AS 4775 eyewash on HF and ammonia workstations

Forgetting that AS 4775 emergency eyewash and shower equipment is mandatory at every HF acid etching workstation, every ammonia mirror silvering tank and every other chemical workstation. Standard AS 4775 eyewash flow 1.5 L/min, shower flow 75 L/min, tepid water at 16-38 degrees Celsius. For HF specifically, the eyewash station must deliver calcium gluconate gel for emergency neutralisation alongside standard water. Not strictly an HVAC issue — but the mechanical services contractor delivering the HF acid etch extract duct is the right party to verify the eyewash is installed and tested.

FAQ

What is the dominant occupational health hazard in glass and mirror plant HVAC design?

Respirable crystalline silica (RCS) generated by cutting, edge grinding, drilling and cullet handling. The Safe Work Australia workplace exposure standard is 0.05 mg/m3 8-hour TWA, with engineering control hierarchy mandated under the 2024 silica reforms. AS 3957 and AS 3640 cover the supporting framework.

Why can galvanised duct never be used on decorative glass HF acid etching?

HF acid attacks galvanised within weeks. SBKJ specifies 304L stainless ductwork (SBAL-V scope at 1.0-1.5 mm) routed to a packed-tower wet scrubber with calcium hydroxide neutralisation. For high-volume HF etching, the duct upgrades to FRP (outside SBKJ machinery scope). AS 4775 emergency eyewash and shower with calcium gluconate gel mandatory at every HF workstation.

What ISO 14644 cleanroom class is required for mirror sputter coating?

ISO 14644 Class 7-8 in load-lock and transport zones, Class 6 inside the sputter chamber (sealed vacuum, no general HVAC). Class 7 demands HEPA H13 filtration, 30-60 ACH, positive pressure 12-25 Pa, 22-24 degrees Celsius, 45-55 percent relative humidity. Galvanised SBAL-V at 0.6-1.0 mm with sealed Pittsburgh seams or welded longitudinal seams to leak-class A air-tightness.

Which SBKJ machine forms the heaviest gauge a glass plant typically needs?

The SBAL-V auto duct production line forms 0.5-1.5 mm galvanised and 304L stainless at 16 m/min and 87 kW installed power, accepting coil widths up to 1500 mm. Covers about 70 percent of glass plant HVAC duct length. The SBKJ duct welding line welds up to 1.6 mm longitudinal seam for the heavier work. Above 1.6 mm — high-temperature tempering furnace roof exhaust — fabrication moves to plate rolling and submerged-arc welding shops outside standard sheet metal duct machinery scope.

How does ISO 12543 laminated glass production affect HVAC design?

The laminating assembly bay is functionally a clean room — HEPA-filtered supply at 12-15 ACH, 20-22 degrees Celsius, 30-40 percent relative humidity, positive pressure 12-15 Pa, low-velocity diffusers above the PVB layup tables. Autoclave room runs general dilution at 4-6 ACH with heat rejection at the autoclave wall and emergency venting interlocked to compressed-air control.

What materials are specified for glass tempering furnace heat extraction?

Tempering furnace runs at 600-700 degrees Celsius continuous. Roof exhaust hood at 1.5-2.5 mm welded mild steel or 304L stainless (outside standard SBAL-V scope, fed by SBKJ duct welding line at 1.6 mm or subcontracted heavy-gauge above that). Downstream of a cooldown header where exhaust drops below 400 degrees Celsius, transition to 1.0-1.5 mm 304L on the SBAL-V. Below 200 degrees Celsius, transition to galvanised SBAL-V. NFPA 86 governs the combustion safety and exhaust stack design.

What air change rate does AS 1668.2 require for a glass processing factory floor?

AS 1668.2 does not specify a single number. The practical design baseline is 6-8 ACH general dilution, supplemented by local-exhaust capture at every silica source (cutting, edge grinding, drilling, sandblasting) per AS 1668.2 Section 6. Acoustic budget NC-50 across the open floor, NC-40 in QA and inspection. Personnel comfort 22-24 degrees Celsius at 45-65 percent relative humidity.

What is the typical lead time for SBKJ machinery for a glass plant retrofit?

SBAL-V auto duct line 60-90 days plus 25-35 days ocean freight to Melbourne, Sydney, Brisbane, Adelaide or Fremantle. SBTF-1500C, SBTF-1602 and SBTF-2020 spiral tubeformers 45-60 days plus shipping. SBFB-1500 cleat folder and SBSF-1525 shear 30-45 days plus shipping. SBKJ duct welding line 60-90 days plus shipping. Total project window from PO to commissioning typically 16-22 weeks. Viridian, Pilkington Australia, G.James and O-I Glass Australia mechanical services contractors typically order 4-6 months ahead of plant shutdown windows.

Which Australian glass and mirror operators specify HVAC duct retrofits?

Viridian Glass (Ingleburn NSW, Dandenong VIC), Pilkington Australia (Dandenong VIC), G.James Glass and Aluminium (Eagle Farm and Yatala QLD plus Sydney, Melbourne, Adelaide, Perth, Townsville), O-I Glass Australia (Penrith NSW), Saint-Gobain Australia (Sydney), Cardinal IG Australia, Australian Glass Group (Melbourne), Bristol Glass (Sydney), Crystal Mirror (NSW), Glass Industries Australia (Perth), Smart Decorative Glass, Schweitzer Glass, Custom Glass Solutions, Vetro Smart Glass, Metro Performance Glass NZ. Mechanical services contractors typically tender duct fabrication and run an SBAL-V, SBAL-III or SBAL-II auto duct line in-house.

What materials are specified for mirror back paint VOC extract?

304L stainless on the SBAL-V at 1.0-1.5 mm. Galvanised will not survive the VOC and partially-cured alkyd or polyurethane back paint resin breakdown products in the extract stream. NFPA 33 governs the spray booth design if solvent-based paint is used; AS/NZS 1668.2 Section 6 covers the booth ventilation. Cross-draught or down-draught booth at 0.4-0.6 m/s face velocity, recovery filter for overspray, activated carbon or thermal oxidiser for VOC abatement.