What component may only be used in series with a pressure relief valve in NH3 systems?

In ammonia (NH3) systems, rupture members play a crucial role in safety and operational integrity. They are designed to act as a form of passive safety device that will rupture at a specified pressure, effectively providing a fail-safe mechanism to prevent pressure buildup in the system. When pressure relief valves are in place, they are intended to allow excess pressure to escape safely, but they can only do so effectively if the system is designed in a way that maintains safety under various operational conditions.

Rupture members are specifically placed in series with pressure relief valves to ensure that if the pressure relief valve were to become inoperative or fail to open, the rupture member would activate, thus preventing potential catastrophic system failure or explosions. This arrangement helps to manage excess pressure and protect the integrity of the system overall.

In contrast, other components like check valves, ball valves, and gate valves have different functions. Check valves are meant to prevent backflow, ball valves and gate valves are used for isolation and throttling, but they do not provide the same safety assurance in balancing pressure management as rupture members do when utilized in conjunction with pressure relief valves in ammonia systems. Thus, the correct answer highlights the unique purpose of rupture members in ensuring safe operational practices in high-pressure environments