Which valve can be used to stop the flow of gas for safety purposes?

A gas shutoff valve is specifically designed to control the flow of gas and stop it completely as needed for safety purposes. This type of valve is essential in gas supply systems, allowing operators to quickly and effectively shut off gas in case of an emergency, maintenance, or leak detection. It is typically located in accessible areas to ensure rapid response to any hazardous situations.

In contrast, a manifold is used for distributing gas but does not serve the primary function of shutting off gas flow. A regulator valve manages the pressure of gas within a system but does not completely stop the flow of gas. Lastly, a flexible gas line is a conduit for delivering gas; it does not control or stop the flow on its own. Therefore, the gas shutoff valve is the most appropriate choice for safety-related gas flow management.