What type of respiratory protective system recycles exhaled air to provide oxygen?

The correct answer is a closed circuit SCBA (Self-Contained Breathing Apparatus). This type of respiratory protective system is designed to recycle exhaled air while providing a continuous supply of oxygen to the user. In a closed circuit system, the exhaled breath is processed through a carbon dioxide scrubber that removes the CO2, allowing the remaining oxygen to be recirculated back to the user. This system offers a longer duration of oxygen supply compared to open circuit systems, making it particularly useful in environments where air supply is limited or for extended operations.

In contrast, an open circuit SCBA releases exhaled air into the environment and draws in fresh air from the atmosphere for inhalation. As a result, this type does not recycle air, which limits its operational time based on the amount of compressed air stored in the cylinders.

An air purifying respirator filters out contaminants from the ambient air but does not provide oxygen independently nor recycles exhaled air, making it unsuitable for scenarios where the oxygen content may be insufficient.

Supplied air respirators deliver fresh air from a source such as a compressor or tank, but like the open circuit SCBA, they do not recycle exhaled air. Instead, they ensure an uninterrupted