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ScbaSCBA is an acronym for Self Contained Breathing Apparatus. It is a device worn by rescue workers, firefighters, and others to provide breathable air in a hostile environment. SCBA devices are filled with filtered compressed air, the same air we breathe normally. An SCBA consists of a full-face mask, regulator, air tank, and a harness with adjustable shoulder straps and waist belt which allows the SCBA to be worn on your back. Typically, an air tank has a capacity of 30 or 45 minutes worth of air, but can be less or more, commonly as low as 15 minutes or as high as 60. Air tanks are made of aluminum, steel, or of a composite construction (usually fiberglass-wrapped aluminum.) The composite tanks are the lightest in weight and preferred by fire departments for that reason, but they also have the shortest lifespan and must be taken out of service after 15 years. Air tanks must be hydrostatically tested every 3 years for composite bottles, and every 5 years for metal bottles. Commonly an SCBA will be of the "positive pressure" type, which supplies a slight steady stream of air in order to ensure against leakage of toxic fumes or smoke into the mask. Not all SCBAs are positive pressure; others are of the "demand" type, which only supply air on demand. All fire departments and those working in toxic environments require the use of the positive pressure SCBA for safety reasons. Another distinction is between open-circuit and closed-circuit SCBAs. Most SCBAs are open-circuit and used air is simply exhaled from the mask. The closed-circuit type is a special SCBA which recirculates exhaled air (see: rebreather), used in situations when an extended supply of air is needed such as mine rescue. As SCBA technology has evolved, different models have evolved for firefighting, versus those designed for other uses not requiring the unit to be heat resistant, such as mining. In the United States, SCBAs used in firefighting must meet guidelines established by the National Fire Protection Association, NFPA Standard 1981. If an SCBA is labeled as "1981 NFPA compliant," it is designed for firefighting. The current version of the standard was published in 2002. SCBA is sometimes incorrectly confused with SCUBA (Self Contained Underwater Breathing Apparatus). See scuba diving for their history and more information on how they work. See also Other uses of the acronym SCBA was also an acronym for two types of naval diving rebreather made by Siebe Gorman in England: - Swimmer Canoeist's Breathing Apparatus: a type of combat frogman's rebreather.
- Submerged Chamber Breathing Apparatus: to keep the air breathable in submerged chambers.
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