A self-contained breathing apparatus (SCBA) is a device worn to provide an autonomous supply of breathable gas in an atmosphere that is immediately dangerous to life or health. They are typically used in firefighting and industry. The term self-contained means that the SCBA is not dependent on a remote supply of breathing gas (e.g., through a long hose). If designed for use under water, it is also known as a scuba set (self-contained underwater breathing apparatus). When not used underwater, they are sometimes called industrial breathing sets. Some types are also referred to as a compressed air breathing apparatus (CABA) or simply breathing apparatus (BA). Unofficial names include air pack, air tank, oxygen cylinder or simply pack, which are mostly used in firefighting.
An open circuit SCBA typically has three main components: a high-pressure gas storage cylinder, (e.g., 2,216 to 5,500 psi (15,280 to 37,920 kPa), about 150 to 374 atmospheres), a pressure regulator, and a respiratory interface, which may be a mouthpiece, half mask or full-face mask, assembled and mounted on a framed carrying harness.[1]
A self-contained breathing apparatus may fall into one of two categories: open-circuit or closed-circuit.[2]
