How long must the hydrostatic pressure be maintained during testing of fire protection piping?

The requirement to maintain hydrostatic pressure during the testing of fire protection piping is set to ensure the integrity and reliability of the system. NFPA 24 specifies that the hydrostatic pressure must be maintained for a duration of two hours. This time frame is critical as it allows for the detection of any potential leaks or weaknesses in the piping system.

Maintaining this pressure for two hours helps in verifying that the system can withstand operational pressures without failing. It confirms the performance of the materials used and helps ensure long-term reliability of the fire protection system. If the test were conducted for a shorter duration, there might not be enough time to identify pressure drops due to minor leaks that could compromise the system.

Thus, adhering to the two-hour requirement is fundamental to ensuring that the fire service mains and their appurtenances will operate effectively in the event of a fire emergency.