G2 Gas Fitter Practice Exam

What component must all liquid withdrawal propane cylinder service valves be equipped with?

1. Safety relief valve

2. Internal excess flow valve

3. Pressure gauge

4. Automatic shutoff valve

The correct answer is: Internal excess flow valve

All liquid withdrawal propane cylinder service valves must be equipped with an internal excess flow valve. This safety feature is critical for preventing excessive flow of propane gas during a potential leak or failure of the system. If the service valve is opened and there is an abnormal flow condition, the internal excess flow valve will automatically close to restrict the flow, thereby minimizing the risk of a fire or explosion. Additionally, having this safety mechanism enhances the overall integrity of propane storage and distribution systems, ensuring they operate safely and effectively under normal conditions. While other components like safety relief valves, pressure gauges, and automatic shutoff valves play important roles in propane systems, the internal excess flow valve specifically addresses the unique challenges associated with liquid withdrawal service valves in propane cylinders.