Which of the following is NOT used to size gas regulators?

• A. Inlet pressure
• B. Pipe size
• C. Volume
• D. Type of ignition system

Answer: (D)

Sizing gas regulators focuses on delivering the right amount of gas at the right pressure given what the system needs. Inlet pressure matters because the regulator must handle the available upstream pressure and still provide the desired downstream pressure at the required flow rate. Pipe size matters because the piping between the regulator and the usage point creates pressure losses; larger or properly sized pipes help keep the downstream pressure from dropping under load. Volume matters because the total amount of gas in the system (including piping and connected equipment) influences how the pressure responds during demand changes and how quickly the system can recover after a surge. The ignition system type does not affect how much gas is delivered or regulated, so it isn’t part of regulator sizing.