How does the EBSS system utilize air from the cylinders?

The Emergency Breathing Support System (EBSS) is designed to enhance the safety of users by allowing an alternate air supply during emergencies. When considering how the EBSS utilizes air from the cylinders, it specifically begins by drawing air from the lower pressure cylinder first. This approach is intentional, as it promotes the equalization of air pressure between the two cylinders, preventing one from being depleted while the other remains full. This function is crucial for maximizing the duration of air supply available to the user in critical situations.

In contrast, utilizing air from both cylinders at once would not effectively balance the air supply and could lead to premature depletion of one cylinder. Additionally, drawing from the higher pressure cylinder first would contradict the design of the EBSS, as it would risk having a remaining cylinder with high pressure but less immediate availability for use. Lastly, the system does not require both cylinders to be full to activate; it can operate as long as there is sufficient air in the cylinders, so the activation condition based on fullness does not apply.