Which valve must be opened manually?

The container valve is the component that must be opened manually in gas systems. This valve is critical for controlling the flow of gas from the container to the piping system. When dealing with non-flammable compressed gases, it is important for operators to manually open this valve to start or stop the flow of gas, allowing for precise control based on operational needs.

In contrast, safety valves and relief valves are designed to operate automatically under certain pressure conditions to prevent overpressure situations. Regulators, on the other hand, adjust the pressure of the gas flowing from the container to a usable level, often functioning automatically once set to the appropriate parameters. Therefore, the necessity for manual operation directly relates to the container valve's role in initiating gas flow from the containment source.