Which system type requires line tightness testing every three years?

• A. American-style suction
• B. Diaphragm-based storage
• C. Conventional gravity venting
• D. Electronic pressure transducer

Answer: (A)

Line tightness testing checks the integrity of piping that carries gas or liquid under pressure, looking for leaks that could develop over time. American-style suction uses a sealed suction line as part of the system, so it’s required to verify that line remains leak-free on a set schedule—every three years—because leaks there can directly affect performance and safety.

Diaphragm-based storage involves a storage vessel with a diaphragm; while leaks are possible, testing and maintenance are centered on the integrity of the diaphragm and vessel rather than a separate external line’s tightness on a fixed interval. Conventional gravity venting vents to the atmosphere, so there isn’t a pressurized line to test for tightness. Electronic pressure transducers provide continuous monitoring and alarms, reducing the need for a periodic line-tightness test; leaks would be detected by sensor data rather than by a standalone triannual test.

Thus, the system type that requires line tightness testing every three years is the American-style suction, since it relies on a sealed, pressurized line whose integrity must be regularly verified.