SCBA

SCBA 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. When not used underwater, they are sometimes called industrial breathing sets.

Open-circuit SCBAs

Open-circuit industrial breathing sets are filled with filtered compressed air, the same air we breathe normally. It has a full-face mask, regulator, air cylinder, cylinder pressure gauge, and a harness with adjustable shoulder straps and waist belt which lets it be worn on the back. Its cylinder usually holds 30 or 45 minutes worth of air, but this can be less or more, commonly as low as 15 minutes or as high as 60 minutes. Air cylinders are made of aluminum, steel, or of a composite construction (usually fiberglass-wrapped aluminum.) The composite cylinders are the lightest in weight and are therefore preferred by fire departments (UK: fire brigades), but they also have the shortest lifespan and must be taken out of service after 15 years. Air cylinders must be hydrostatically tested every 3 years for composite cylinders, and every 5 years for metal cylinders.

Commonly an SCBA will be of the "positive pressure" type, which supplies a slight steady stream of air to stop toxic fumes or smoke from leaking 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 need to use the positive pressure SCBA for safety reasons.

As SCBA technology has evolved, different models have evolved for firefighting, versus those designed for where the set does not need to be heat resistant, such as in mining. In the USA, 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.

Closed-circuit SCBA's

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 gas: (see rebreather for more information), used when a longer-duration supply of air is needed such as in mine rescue . Before open-circuit scuba came, most industrial breathing sets were rebreathers, such as the Proto and the Salvus.

SCBA and scuba

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. The first open-circuit industrial breathing sets of the modern type were modified (or unmodified) open-circuit diving scuba sets.

See also

• Glossary of firefighting terms
• PASS device

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: formerly used to keep the air breathable in submerged chambers.