Isolation/Shut-off: Completely stopping the flow of gas for safety or maintenance.
Flow Regulation: Controlling the rate at which gas flows to an appliance (e.g., controlling the flame size on a stove or burner).
Safety/Protection: Automatically shutting off flow in response to pressure surges, temperature changes, or mechanical failure (e.g., slam-shut valves).
Backflow Prevention: Ensuring gas travels in only one direction, preventing contamination or dangerous pressure issues in the supply line.