Which valve must be installed in sections of piping to ensure liquid propane can be safely vented?

The hydrostatic relief valve is essential in sections of piping to safely vent liquid propane. This type of valve is specifically designed to open at a predetermined pressure, allowing excess pressure to be released from the system.

In the context of propane systems, liquid propane can create high pressures as temperatures rise, which can lead to safety hazards if not properly managed. The hydrostatic relief valve actively helps prevent overpressure scenarios by venting the excess vapors or liquids to a safe area, ensuring that the system remains within safe operational limits.

This valve is crucial, especially in storage tanks and piping systems, to manage situations that may lead to pressure buildup. By facilitating the safe release of vapor or liquid propane, it significantly reduces the risk of explosions or leaks that could occur due to excessive pressures.

While other types of valves such as manual valves, shutoff valves, and backflow valves serve important functions in a propane system — like controlling flow, shutting off the system in emergencies, and preventing the reverse flow of gas — they do not serve the specific purpose of relieving excess pressure like the hydrostatic relief valve does. Therefore, in the context of enabling safe venting of liquid propane, the hydrostatic relief valve is the appropriate choice.