What occurs when a SCBA cylinder is running low on air?

When a Self-Contained Breathing Apparatus (SCBA) cylinder is running low on air, the continuous sounding of the alarm is a critical safety feature designed to alert the user. This alarm system is activated when the air pressure in the cylinder drops to a pre-determined level, indicating that the available air supply is getting low. The purpose of this alarm is to provide a clear and immediate warning to the user, allowing them to take appropriate action, such as exiting the hazardous environment or switching to a backup air supply.

Understanding the role of this alarm is essential for safety in environments where SCBA is used, as it serves to prevent users from unexpectedly running out of breathable air, which could lead to dangerous situations. The other options, while related to the operation of the SCBA, do not directly indicate the low air situation as clearly, making the continuous alarm the most relevant indicator of low air conditions.