Shielding-Gas Cylinder Runtime and Cost
Gas used, runtime per cylinder, cylinders needed, and the prorated gas cost from a flow setting and arc-on time.
Example
You enter
- Gas flow (cfh) 35
- Arc-on time (min) 120
- Usable gas per cylinder (ft3) 251
- Cost per cylinder (optional) 60
You get
- Gas used 70 ft3
- Runtime per cylinder 7.2 hr
- Cylinders needed 1 cylinder(s)
- Gas cost for the job 16.7331
Checked against published worked examples from: Torch / regulator maker's flow charts / AWS welding cost references.
Details, formula, and sources
ScopeCompressed-gas and hot-work hazards govern; follow the maker's instructions and your hot-work permit.
Formula or tableGas used = flow x arc-on / 60; runtime per cylinder = cylinder volume / flow; cylinders = ceil(gas used / cylinder volume); job gas cost = (gas used / cylinder volume) x cost per cylinder, prorated.
Source and editionTorch / regulator maker's flow charts and the AWS welding cost / consumable references, by name.
Free accessThe flow-to-volume arithmetic is public; the maker's flow chart ships with the regulator.
What governsMath aid for personal verification. Stop work and consult the qualified person on site if any number does not match the field condition.
API field namesflow_cfh, arc_on_min, cylinder_ft3, gas_cost, gas_used_ft3, runtime_hr_per_cyl, cylinders_needed, job_gas_cost
- Usable cylinder volume a '330' cylinder holds about 251 ft3 of argon mix (also 145, 80); editable to the bottle on handgas supplier cylinder spec
- Flow setting set the flow to the gun and the joint, not higher -- excess gas wastes money and causes turbulence and porosity; a windscreen beats cranking the flowwelding practice