Technical resource — manifold & cylinder sizing

Acetylene Flow Rate Chart — Safe Cylinder Withdrawal Rates

Acetylene is dissolved in acetone inside the cylinder — draw gas too fast and acetone comes out with it, starving the flame, contaminating the work and damaging the cylinder. This chart gives the safe withdrawal rates every fabricator and manifold designer should size against.

The 1/7 and 1/10 rules

Because acetylene must come out of solution in acetone before it leaves the cylinder, the safe withdrawal rate is a fraction of the cylinder’s total contents per hour — not a fixed flow. Industry practice (CGA/EIGA guidance) limits withdrawal to about 1/7 of the cylinder contents per hour for intermittent use (typical torch work), and about 1/10 of contents per hour for continuous service such as machine cutting or process burners.

Draw faster and acetone mist carries over into hoses and torches, cylinder pressure drops misleadingly, and repeated abuse degrades the porous mass and solvent charge. The answer is never a hotter regulator setting — it is more cylinders on a manifold.

Maximum continuous withdrawal by manifold size (1/10 rule)

Rates in m³/hr of acetylene for full cylinders manifolded together, by cylinder capacity. For intermittent torch work the 1/7 rule allows roughly 40% more.

Cylinders on manifold2 m³ cylinder4 m³ cylinder6 m³ cylinder8 m³ cylinder
10.2 m³/hr0.4 m³/hr0.6 m³/hr0.8 m³/hr
20.4 m³/hr0.8 m³/hr1.2 m³/hr1.6 m³/hr
30.6 m³/hr1.2 m³/hr1.8 m³/hr2.4 m³/hr
40.8 m³/hr1.6 m³/hr2.4 m³/hr3.2 m³/hr
51.0 m³/hr2.0 m³/hr3.0 m³/hr4.0 m³/hr
61.2 m³/hr2.4 m³/hr3.6 m³/hr4.8 m³/hr
81.6 m³/hr3.2 m³/hr4.8 m³/hr6.4 m³/hr
102.0 m³/hr4.0 m³/hr6.0 m³/hr8.0 m³/hr
122.4 m³/hr4.8 m³/hr7.2 m³/hr9.6 m³/hr
163.2 m³/hr6.4 m³/hr9.6 m³/hr12.8 m³/hr
204.0 m³/hr8.0 m³/hr12.0 m³/hr16.0 m³/hr

Sizing a manifold: divide your process demand by one-tenth of your cylinder capacity. Example — a cutting line needing 3 m³/hr from 6 m³ cylinders requires 3 ÷ 0.6 = 5 cylinders on line. Keep the cylinder size consistent on the manifold after installation, or the safe rate changes with it.

What else changes the safe rate

  • ✓Temperature — cold cylinders release gas more slowly; below ~5 °C derate further, and never heat a cylinder with a flame
  • ✓Cylinder fill level — a part-empty cylinder holds less gas, so its safe hourly rate falls proportionally
  • ✓Duty cycle — intermittent torch work tolerates the 1/7 rule; continuous burners and machines should use 1/10
  • ✓Always fit flashback arrestors on the manifold and at each station, and keep DA cylinders upright in use

IIGAS manufactures acetylene manifolds, uniflow valve-cum-flashback arrestors and DA cylinders, and supplies dissolved acetylene across eastern and central India — if your demand has outgrown single cylinders, we will size and build the manifold.

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Frequently asked questions

About 1/7 of the cylinder contents per hour for intermittent torch work, and 1/10 per hour for continuous service. A full 6 m³ DA cylinder safely gives about 0.85 m³/hr intermittent or 0.6 m³/hr continuous.
Acetone is carried out with the gas — the flame degrades, the work is contaminated, the cylinder loses solvent and its porous mass can be damaged, and cylinder pressure reads misleadingly low.
Divide your process demand (m³/hr) by one-tenth of the cylinder capacity. A 3 m³/hr continuous demand from 6 m³ cylinders needs 5 cylinders on line.
Yes — gas comes out of solution more slowly in cold cylinders, so derate in cold conditions. Never apply flame heat to a cylinder; bring more cylinders on line instead.
Yes — we manufacture acetylene manifolds with uniflow valve-cum-flashback arrestors and supply filled DA cylinders, so the whole installation comes from one source.

Need a gas supply or a gas plant?

Talk to International Industrial Gases Ltd about cylinders, bulk supply, medical gases or a turnkey acetylene gas plant.