What happens to the primary reducer when the bottle pressure falls below 1825 psi?

When the bottle pressure falls below 1825 psi, the primary reducer is designed to close. This closure is a safety feature aimed at protecting the user in case of low-pressure situations. By closing, the primary reducer prevents any further air from flowing out of the cylinder, thereby ensuring that the remaining air pressure is conserved for essential use, especially in emergencies when each breath of air is critical.

This mechanism prevents the user from running out of breathable air unexpectedly, as it stops the release of air when it detects a pressure that could compromise the safety of the breathing apparatus. Maintaining integrity in the air supply is crucial, which is why this design is in place within the SCBA system.