Which factor does not determine the rate at which acetylene can be drawn from a cylinder?

• A. Temperature of the cylinder
• B. Capacity of the cylinder
• C. Amount of acetylene remaining
• D. All of the above

Answer: (C)

The speed you can draw acetylene from a cylinder is set by the pressure delivered through the regulator, which is influenced by the gas temperature inside the cylinder. As temperature rises, the gas pressure increases and the regulator can push gas out more quickly; as temperature falls, pressure drops and the draw rate can slow. The amount of acetylene left in the cylinder doesn’t itself set the flow rate—the regulator maintains the chosen flow as long as the pressure remains above its minimum. Only when pressure gets too low will the flow dwindle. The size or capacity of the cylinder doesn’t change the rate either; it mainly determines how long you can sustain that rate before the gas is exhausted. Therefore, the factor that does not determine how fast acetylene can be drawn is the amount of acetylene remaining.