What audible alarm signal is produced when the low air alarm activates?

When the low air alarm activates, a progressively louder, sweeping audio signal is produced. This type of signal is designed to alert the wearer of the self-contained breathing apparatus (SCBA) to the fact that the air supply is running low. The sweeping nature of the sound helps ensure that it effectively garners attention in high-stress environments, such as a fire scene, where background noise can be significant. The progressive increase in volume also serves to indicate the urgency of the situation, encouraging prompt action to escape or refill the air supply. This auditory cue is crucial for maintaining safety in hazardous environments where timely responses are essential for survival.