What happens once Segment 4 is reached?

Upon reaching Segment 4, the signaling system within the SCBA activates the LEDs, which begin to flash. This flashing is an important alert and indicates to the user that they are in a critical state regarding their air supply or the unit’s performance. The visual signal serves as a reminder for the user to take appropriate action, such as planning for an exit from the hazardous environment due to the diminishing air supply.

The other options, while they may represent alternative functionalities or states of the equipment, do not accurately describe the specific behavior of the SCBA upon reaching Segment 4. Understanding the correct operational signal is crucial for the safety and awareness of the user in potentially dangerous situations.