An acetylene burner releases heat by burning acetylene with an oxidizer. This animation shows an oxy-acetylene welding torch: separate gas passages lead to a mixer and nozzle beside the workpiece. Enter fuel flow and heating value to compare chemical heat input; the result does not select a tip or predict weld penetration.
Acetylene Burner Interactive Calculator
Compare chemical heat input from acetylene flow and heating value. Plate thickness gives a power-per-thickness comparison; the oxygen card uses an approximate equal-flow assumption.
Equation Used
The calculator multiplies fuel flow by the entered heating value. This is chemical energy per unit time, not heat absorbed by the workpiece. The Neutral O2 card assumes equal oxygen and acetylene flow at the torch; use the actual equipment and process data for gas requirements.
- Acetylene flow is entered as standard cubic feet per hour.
- Heating value must use the same standard-volume reference as fuel flow. Confirm whether the supplied value is on a lower or higher heating-value basis; the calculator does not convert between them.
- The oxygen card is an approximate 1:1 torch-flow assumption, not a regulator setting or the total oxygen required for complete combustion.
- Calculated heat is chemical heat release, not net heat absorbed by the workpiece.
Gas path through the illustrated torch
Separate hoses supply fuel and oxygen to the torch. Control valves meter the gases into a mixing arrangement, and the mixture reaches the nozzle where the flame forms. The drawing identifies the handle, nozzle and plate; it is not a pressure or flow-path design for a particular torch.
A simplified primary reaction is C₂H₂ + O₂ → 2CO + H₂. Those products can then burn with additional oxygen in the surrounding envelope. The complete reaction is C₂H₂ + 2.5O₂ → 2CO₂ + H₂O. The oxygen entering a welding torch is therefore not necessarily the entire oxygen requirement for complete combustion.
Changing the fuel–oxygen proportion changes flame chemistry. Choosing a flame condition requires the material, filler and welding or brazing procedure. The animation does not determine that condition from the displayed heat input.
Equipment functions
- Regulators: provide the gas supply conditions specified for the equipment.
- Hoses and valves: carry and meter the designated gases.
- Mixer and nozzle: establish the intended mixing and discharge arrangement.
- Reverse-flow check valves: oppose reverse gas flow.
- Flashback arrestors: limit flame propagation toward the supply when correctly selected and installed.
Check valves and flashback arrestors perform different functions. Follow the equipment manufacturer’s instructions for compatible components, installation and inspection. Do not use this energy calculator to choose pressures or alter a nozzle.
Welding, heating and cutting
Oxy-acetylene equipment can provide localized heat for welding, brazing and heating when the equipment and procedure suit the work. Air-acetylene burners and carbide lamps use different oxidizer supplies and burner arrangements from the twin-gas welding torch shown here.
Oxy-fuel cutting also uses a separate cutting-oxygen stream to oxidize and remove metal after preheating. Its oxygen demand and cutting performance cannot be inferred from this calculator’s equal-flow welding assumption.
Tip designations are manufacturer- and product-specific. Compare the exact torch and tip documentation rather than treating a numbered tip as a universal flow or thickness rating.
Fuel energy rate
With acetylene flow V in standard cubic feet per hour and heating value HV in BTU per standard cubic foot, chemical power is Q = V×HV in BTU/h. Multiply by 0.00029307107 to obtain kW.
The flow and heating value must share compatible reference temperature and pressure. A mass-based heating value requires mass flow instead; kg/s cannot be multiplied directly by BTU/SCF.
The Heat per mm card divides chemical power in kW by the entered plate thickness in mm. It is a comparison quotient, not welding heat input in J/mm of travel and not a weldability criterion. Travel speed, heat-transfer efficiency, joint geometry and material properties are absent.
The oxygen display is VOâ‚‚ = VCâ‚‚Hâ‚‚ under its approximate torch-flow assumption. Neither regulator pressure nor total combustion oxygen is calculated. Flame temperature and absorbed heat are also not outputs.
Worked example: comparing fuel inputs
Take an illustrative entered heating value of 1,470 BTU/SCF. At 5 SCFH, Q = 5×1,470 = 7,350 BTU/h, or approximately 2.154 kW. With plate thickness 3 mm, the comparison quotient is 2.154/3 ≈ 0.718 kW/mm. The oxygen card shows 5 SCFH under its equal-flow assumption.
At the same entered heating value, 1 SCFH gives 1,470 BTU/h ≈ 0.431 kW; 20 SCFH gives 29,400 BTU/h ≈ 8.616 kW. These results follow directly from the selected flow and heating-value basis.
No tip number, operating pressure or suitable plate thickness follows from these values alone. They do not establish a welding procedure, melt time, penetration or cylinder withdrawal capacity. Confirm the fuel data and actual equipment ratings before using a heat estimate for planning.
Comparing burner systems
| System | What differs |
|---|---|
| Oxy-acetylene welding torch | Supplied oxygen and acetylene mix in a torch arrangement intended for the specified process. |
| Air-acetylene burner | Uses air as the oxidizer; mixing, flame characteristics and applications differ. |
| Other oxy-fuel systems | Fuel properties, required oxygen, mixer, tip and supply equipment must be compatible. |
Compare specific equipment and procedures for performance and cost. A fuel substitution is not simply a change in the heating-value slider; it may require different rated components and operating instructions.
Acetylene-burner questions
No. Backfire, sustained backfire and flashback are distinct events with several possible causes. Follow the equipment’s shutdown and inspection instructions and do not relight a suspect system until its condition is established. The calculator cannot diagnose the cause.
No. It is an approximate equal-flow comparison. The actual gas requirements and flame condition depend on the torch, tip and process; a fixed valve turn is not a universal adjustment.
No. Cutting also depends on the cutting-oxygen stream, material, thickness, tip, stand-off and travel conditions. This model has no cutting-oxygen input or metal-oxidation calculation.
No. Permitted withdrawal depends on the cylinder and supply conditions. Use the gas supplier’s instructions and the equipment’s required flow. This calculator does not size cylinders or manifolds.
No. Check valves resist reverse flow; arrestors are intended to stop flame propagation. The required arrangement, capacity and service response are equipment-specific.
No. It only changes the section drawing and divides power by thickness. It does not model the joint, heat transfer or a manufacturer’s tip chart.
Gas contamination, preparation, material, filler, heat and procedure can all matter. Porosity does not by itself identify a flame adjustment. Use the applicable joining procedure and investigate the actual work conditions.
References and further reading
- TWI: What is oxy-fuel welding?, process distinctions and flame chemistry.
- ESAB Academy: Avoiding Unwanted Ignition Incidents, distinctions between backfire and flashback and the roles of protective devices.
- TWI: Oxyacetylene welding, cutting and heating, equipment and handling considerations.
Use the current manual and supplier instructions for the exact equipment in service.
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