Self-Contained Breathing Apparatus
In addition to the turnout gear, in most instances we also must wear SCBA or Self-Contained Breathing Apparatus (not to be confused with SCUBA gear, which is for use under water). The SCBA we use in our department are manufactured by Scott. SCBA are the air tanks that you see on the back of a firefighter along with the mask on her/his face. We use them whenever there is a fire or the potential threat of a hazardous condition or environment. What that boils down to is we wear them on almost all incidents.
Inside the air tanks is normal breathing air (about 21% oxygen) that gets fed into the mask through a pressure regulator. The air bottles that we use on our airpaks are filled to about 4500 psi when full, which gives you about a 15-20 minute air supply under heavy working conditions. When air in the bottle gets low an alarm sounds indicating the need to replace your bottle.
Before, During & After the Fire
Read more about how fire suppression works.