Where the optional read-only pressure transducer is installed, the sprinkler-riser / fire-pump water pressure (or, on a dry system, the supervisory air pressure) is out of band or drifting toward the panel's supervisory threshold — an early sign of a valve creeping shut, supply degradation, a small leak, or jockey-pump short-cycling, caught before the panel's single-threshold switch trips.
fire_system_readinesspressure out of band OR pressure trending toward supervisory_threshold (raises pressure drift; requires optional transducer)