What does an open circuit breathing apparatus do?

An open circuit breathing apparatus is designed to provide fresh air to the user from a compressed air cylinder. When the user inhales, clean air is delivered from the cylinder, and upon exhaling, the exhaled air is released into the atmosphere rather than being recirculated. This design ensures that the firefighter receives breathable air while working in environments where the atmosphere may be detrimental to health, such as during firefighting operations.

The system’s operation is straightforward and vital for safety, as it allows for immediate dissipation of exhaled carbon dioxide, preventing any buildup of harmful gases that could lead to suffocation or reduced oxygen availability. This makes the open circuit breathing apparatus especially useful in environments with contaminated air, as it relies on an external source of oxygen rather than attempting to purify or recycle the air within the system.