Which statement best describes the testing sequence for intermediate and high-pressure water mist systems?

Which statement best describes the testing sequence for intermediate and high-pressure water mist systems?

• A. A single pressure test at the working pressure suffices.
• B. Two pressure tests are required: an initial test of 10 minutes followed by a 110-minute working-pressure test.
• C. Three pressure tests are required: 10 minutes, 60 minutes, and 120 minutes.
• D. One test of 120 minutes at working pressure plus a leak test.

Answer: (B)

Testing sequence for intermediate and high-pressure water mist systems focuses on verifying both immediate integrity and sustained performance under operating conditions. The two-test approach starts with a short 10-minute test to quickly reveal any obvious leaks or connections that aren’t secure when pressure is first applied. This step helps catch issues that could appear during setup or initial pressurization. Following that, a longer 110-minute test at the working pressure checks that the system can hold pressure reliably for the full duration it would experience in service. This validates that there are no hidden leaks, that seals and fittings maintain integrity under sustained load, and that the system will perform as expected in a real fire scenario. This combination is preferred because a single test at working pressure could miss leaks or weaknesses that only show up during initial pressurization, while procedures with extra or differently timed tests add steps not required by the standard. A two-stage sequence with an initial short test plus a longer working-pressure test exactly aligns with the intended verification of both assembly integrity and endurance under operating conditions.

Testing sequence for intermediate and high-pressure water mist systems focuses on verifying both immediate integrity and sustained performance under operating conditions. The two-test approach starts with a short 10-minute test to quickly reveal any obvious leaks or connections that aren’t secure when pressure is first applied. This step helps catch issues that could appear during setup or initial pressurization.

Following that, a longer 110-minute test at the working pressure checks that the system can hold pressure reliably for the full duration it would experience in service. This validates that there are no hidden leaks, that seals and fittings maintain integrity under sustained load, and that the system will perform as expected in a real fire scenario.

This combination is preferred because a single test at working pressure could miss leaks or weaknesses that only show up during initial pressurization, while procedures with extra or differently timed tests add steps not required by the standard. A two-stage sequence with an initial short test plus a longer working-pressure test exactly aligns with the intended verification of both assembly integrity and endurance under operating conditions.