According to NFPA 25, how often should a wet pipe system's main drain valve be tested?

The frequency of testing the main drain valve for a wet pipe sprinkler system, as outlined in NFPA 25, is specified to be annually. This annual testing is crucial because it helps ensure that the main drain valve is functioning correctly, allowing for the effective drainage of the system when needed. Over time, sediment and debris can accumulate in the pipe, which could affect the performance of the system in a fire emergency.

Annual testing ensures that the valve can fully open and allow water to drain from the system, confirming that the system is in compliance with safety standards and ready to operate effectively when required. Regular testing, such as this annual check, forms part of the ongoing maintenance required to ensure that sprinklers operate properly and reliably during an incident.

This testing requirement is designed to reduce the risk of system failure due to valve malfunction, thereby enhancing the overall reliability of the fire protection system.