According to NFPA 25, what is the maximum allowable pressure drop in a dry pipe system during a nitrogen or air test?

The maximum allowable pressure drop in a dry pipe system during a nitrogen or air test, as stated in NFPA 25, is indeed 3.0 psi. This standard ensures that the dry pipe system is adequately tested for leaks and maintains operational integrity without excessive pressure loss, which could indicate a potential failure in the system. By adhering to this limit, it is ensured that any significant drop in pressure during testing can trigger further investigation to ensure that the system is functioning correctly, ultimately contributing to effective life safety measures and reliable fire protection. Maintaining pressure within this range is vital for confirming that the dry pipe system is sealed properly and can perform as intended in the event of a fire.