What Is an Industrial Fire-Tube Boiler?
The Ever-power industrial fire-tube boiler is a packaged steam boiler built around a scotch-marine shell. Hot combustion gases from the burner travel through a corrugated furnace tube and then back through banks of smoke tubes, transferring heat to the water surrounding them. Steam forms in the upper half of the shell and is drawn off through a steam drum at saturation pressure.
This is the most proven steam-boiler architecture in world industry — the Australian food, textile, pharmaceutical, hospital, hotel and chemical sectors have used versions of it for over a century. Ever-power builds the modern wet-back three-pass and four-pass variants with full AS/NZS 3788 inspection documentation, low-NOx burner trains and optional stack economiser that pushes thermal efficiency above 95%.
Compared with a water-tube boiler at the same capacity, a fire-tube unit offers a compact footprint, simple operation, lower capital cost and easier day-to-day maintenance. It is the standard choice up to about 25 t/h and is available as a dual-fuel unit running natural gas, LPG, diesel or light fuel oil — with an optional waste liquid incinerator tie-in where a chemical plant wants to co-fire process off-gas.
Pass Configurations & Fuel Options
Three-Pass Wet-Back
Standard configuration for 1–15 t/h. Corrugated Morrison furnace plus two smoke-tube passes. Wet-back reversal chamber removes refractory maintenance at the rear.
Four-Pass Wet-Back
Selected for 10–35 t/h duties and for sites targeting maximum efficiency. Extra pass drops stack temperature ~25 °C lower than three-pass at the same load.
Natural Gas & LPG
Weishaupt, Riello or Limpsfield low-NOx burners matched to AGL, Origin or Jemena gas specifications. Full flame-safeguard and interrupted pilot.
Diesel & Light Fuel Oil
Air-atomising burner, oil preheater and booster pump skid for remote or backup operation — ideal for sites with unreliable gas supply.
Dual-Fuel (Gas + Oil)
Swap-fire between primary gas and standby oil with automatic change-over. Critical for hospital, data centre and food-processing campuses.
Biogas & Hydrogen-Ready
Digester gas, landfill gas and up to 30% H₂ blend compatible. Hydrogen-ready burner upgrades offered for sites preparing for decarbonisation.
How the Industrial Fire-Tube Boiler Works
Combustion, heat transfer and steam separation all take place inside one horizontal pressure shell. Five operational stages define the steam cycle.
Burner Firing
A modulating low-NOx burner fires into a corrugated Morrison furnace. Flame length and shape are controlled to prevent impingement on the rear tube plate.
First Pass — Radiant Furnace
Flue gas at 1,300–1,500 °C transfers radiant heat to the water through the furnace wall, cooling to about 950 °C by the reversal chamber.
Smoke Tube Passes
Two (or three) banks of smoke tubes carry flue gas forward and back, transferring convective heat. Stack exit temperature typically 200–230 °C.
Steam Separation
Generated steam rises to the top of the shell, passes through baffle and mesh separators, and leaves via the main stop valve at ≥ 98% dryness fraction.
Economiser & Stack
Optional stack economiser preheats boiler feedwater using exit flue gas — typically lifting overall efficiency from ~90% to 95%+.
Key Features & Engineering Advantages
Factory-Tested Package
Boiler, burner, control panel and trim valves are skid-assembled, hydro-tested and fire-tested in the factory — not a collection of parts to assemble on site.
Corrugated Morrison Furnace
Wave-form furnace tube absorbs thermal expansion and keeps the pressure shell free from cyclic-fatigue cracks — the classic failure mode on flat furnace boilers.
Low-NOx Burner Standard
Staged combustion burners deliver < 80 mg/Nm³ NOx on natural gas without flue gas recirculation — a clean replacement of legacy Weishaupt-era burners.
Modulating Control 5:1 to 10:1
Infinite modulation across a wide turn-down range holds steam pressure tight on swinging process demand — ideal for batch food, textile and pharma sites.
Trim & Safety Package
Two independent low-water cut-offs, AS3814-compliant safety valves, TDS probe, blowdown valve set, and alarm horn — no kit to source separately.
Remote Monitoring
Siemens or Rockwell PLC + HMI with optional VPN link to Ever-power engineers. Early alerts on flame instability, condensate losses, and tube fouling.
Technical Specifications
Standard packages cover 1–35 t/h on saturated steam from 0.8 MPa to 2.5 MPa. Higher pressures and superheated duty are available on request — fire-tube boilers above 35 t/h are less common and water-tube boilers usually serve that segment better.
| Model | Steam Output (t/h) | Pressure (MPa) | Passes | Footprint (L × W × H) m | Efficiency* |
|---|---|---|---|---|---|
| EP-FT-1 | 1 | 0.8 / 1.0 | 3-pass | 3.8 × 1.6 × 2.0 | ≥ 93% |
| EP-FT-4 | 4 | 1.25 / 1.6 | 3-pass | 5.1 × 2.2 × 2.5 | ≥ 94% |
| EP-FT-10 | 10 | 1.25 / 1.6 / 2.5 | 3 or 4-pass | 6.8 × 2.8 × 3.1 | ≥ 95% |
| EP-FT-20 | 20 | 1.6 / 2.5 | 4-pass | 8.5 × 3.2 × 3.6 | ≥ 95% |
| EP-FT-35 | 35 | 2.5 | 4-pass | 11.2 × 3.8 × 4.2 | ≥ 95% |
*Thermal efficiency with optional stack economiser on natural gas firing at 100% MCR.
Emissions & Compliance
| Parameter | Ever-power (natural gas) | Reference Standard |
|---|---|---|
| NOx | < 80 mg/Nm³ | NSW POEO 350 mg/Nm³ |
| CO | < 40 mg/Nm³ | 125 mg/Nm³ |
| Particulates | < 5 mg/Nm³ | 30 mg/Nm³ |
| Pressure Code | ASME Section I + U stamp | AS/NZS 3788 |
| Noise @ 1 m | ≤ 82 dB(A) | AS 1055 |
| Safety Interlocks | Dual LWCO + flame safeguard | AS 3814 / AS 2593 |
Applications Across Australian Industry
Food & Beverage
Dairy processing, meat rendering, beer brewing, UHT lines, retort sterilisation. Swinging batch loads handled on modulating control.
Textile & Laundry
Dye house, finishing line, commercial laundry, carpet manufacture. Typically 4–10 t/h duty in Australian operators.
Pharmaceutical & Healthcare
GMP reactor heating, autoclave supply, hospital sterilisation. Clean-steam package available as a secondary loop.
Campus & Hospitality
University, hospital and hotel steam utilities; N+1 redundancy for mission-critical services.
Chemical & Light Industrial
Resin, adhesive, paint and coatings manufacturing. Optional co-firing with waste liquid incinerator off-gas.
Building Materials & Timber
Plasterboard, fibre cement, timber kilns and pressure treatment; steam plants sized 3–20 t/h.
Why Choose Ever-power
Fire-tube boilers look like a commodity until you need one that actually hits its nameplate efficiency, passes AS/NZS 3788 first time, and keeps running through a six-year warranty cycle. Six engineering commitments set Ever-power apart from a generic replacement of imported packaged boiler.
More on our factory certification and QA process is on the Ever-power company page, or see the full boiler and waste liquid incinerator catalogue on our home page.
Australian Project Case Studies
Dairy Processing Plant — Greater Bendigo
A mid-size dairy was running two 30-year-old package boilers at 68% average efficiency. Insurance audit flagged the safety valves and a scheduled shutdown had been pencilled in for six months later.
Ever-power solution: Two EP-FT-10 four-pass wet-back fire-tube boilers with low-NOx gas burners, stack economisers and shared deaerator / feedwater skid.
Result: Natural gas consumption cut 32%, annual saving A$640k. Commissioning completed inside the planned 21-day shutdown, full AS/NZS 3788 inspection first-time-pass.
University Campus — Brisbane
A campus steam utility needed to replace one of three N+1 redundant boilers with a higher-efficiency unit while maintaining 24/7 supply to medical, research and catering facilities.
Ever-power solution: EP-FT-4 three-pass dual-fuel (gas + diesel) fire-tube boiler with remote-monitoring VPN link, as a direct replacement of end-of-life unit.
Result: Campus steam supply uninterrupted across the change-out. First-year efficiency measured at 95.2% on natural gas.
Frequently Asked Questions
Fire-tube versus water-tube — which is right for my site?
Fire-tube wins on simplicity, capital cost and footprint up to about 25 t/h at pressures under 2.5 MPa. Water-tube wins above that capacity, for superheated steam above 350 °C, and where rapid load swing and high cycle count matter. For typical Australian food, textile, pharma, hospital and campus duty, fire-tube is the natural fit.
Three-pass or four-pass — what’s the real difference?
Four-pass drops the stack exit temperature by roughly 25 °C at the same load, which adds about 1–1.5 percentage points of efficiency. In return the shell is slightly longer and flue gas pressure drop is higher. On gas prices above A$12/GJ, four-pass usually pays back the modest capital uplift inside two years.
What water quality does the boiler need?
Boiler feedwater should meet AS 3814 for shell boilers above 0.35 MPa: conductivity under 3,500 µS/cm, TDS under 3,500 mg/L, hardness under 5 mg/L as CaCO₃, oxygen under 0.02 mg/L, pH 8.5–10.5. A reverse-osmosis or softener + deaerator package is usually supplied with the boiler to hold those numbers.
Can I run the boiler on biogas or a hydrogen blend?
Biogas is straightforward — we have reference sites on digester gas with scrubbing and a siloxane guard. Hydrogen blends up to 30% are feasible on most low-NOx burners with minor valve-train modifications; 100% hydrogen requires a dedicated H₂ burner and updated flame safeguard logic, which is available as a future-retrofit kit.
What operator class is required to run this boiler in Australia?
The boiler licence class depends on the state and the heating surface or steam output. Most jurisdictions require a Standard Boiler Operator certificate for shell boilers up to 25 t/h saturated at 2.5 MPa. High-hazard licences apply above that threshold. We provide licensing guidance and training material with every handover.
How often does the boiler need inspection and internal cleaning?
AS/NZS 3788 typically calls for an external inspection every 12 months and an internal inspection every 24 months for low-risk plant. Internal fire-side cleaning is usually a 12-month task on urban gas sites and every 6 months on dusty industrial sites. Automatic soot-blower retrofits are available for dusty duty.
Do you support existing boilers not supplied by Ever-power?
Yes. We carry out retubing, refractory replacement, burner upgrade and control-panel retrofit on most shell boilers from major Australian and imported brands. A condition survey is the first step and typically takes one site day plus a report.
Need a Fire-Tube Boiler Sized for Your Plant?
Send your steam demand curve, fuel type and site details to sales@rtooxidizer.com or use the contact page. A full sizing, GA drawing and budget price will be returned within 10 working days — free of charge.