The preferred method of measuring shielding gas supply is which unit?

The preferred method of measuring shielding gas supply is which unit?

• A. Kilograms per square centimetre (pounds per square inch)
• B. Kilograms per minute (pounds per hour)
• C. Litres per minute (cubic feet per hour)
• D. Surface metres per minute (surface feet per hour)

Answer: (C)

Shielding gas needs to be delivered as a flow of gas to protect the weld area, not just kept under pressure. The quantity that matters is how much gas actually moves past the nozzle each minute, which is a volumetric flow rate. That’s why the unit shown—litres per minute—is the standard way to measure shielding gas supply. It directly reflects the amount of shielding gas reaching the weld and is commonly paired with its imperial counterpart, cubic feet per hour. Pressure numbers (pounds or kilograms per square centimeter) tell you how hard the gas is pushed, not how much gas is getting through to the weld. A mass flow rate (kilograms per minute) would require knowing the gas’s temperature and pressure to convert to a usable flow at the weld, which adds unnecessary complexity for typical welding setups. And surface flow rate (metres or feet per hour) has nothing to do with shielding gas delivery at the weld.

Shielding gas needs to be delivered as a flow of gas to protect the weld area, not just kept under pressure. The quantity that matters is how much gas actually moves past the nozzle each minute, which is a volumetric flow rate. That’s why the unit shown—litres per minute—is the standard way to measure shielding gas supply. It directly reflects the amount of shielding gas reaching the weld and is commonly paired with its imperial counterpart, cubic feet per hour.

Pressure numbers (pounds or kilograms per square centimeter) tell you how hard the gas is pushed, not how much gas is getting through to the weld. A mass flow rate (kilograms per minute) would require knowing the gas’s temperature and pressure to convert to a usable flow at the weld, which adds unnecessary complexity for typical welding setups. And surface flow rate (metres or feet per hour) has nothing to do with shielding gas delivery at the weld.