Self-contained breathing apparatus
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. If designed for use under water, it is also known as a scuba set. 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.
Toronto firefighter wearing an SCBA
In an atmosphere that may be oxygen-deficient, an air supply is carried on the back.
Siebe Gorman Savox in a coal mining museum
A person wearing an MSA brand breathing mask with a Nomex hood. This face piece attaches with a regulator to form a full SCBA.
Immediately dangerous to life or health
The term immediately dangerous to life or health (IDLH) is defined by the US National Institute for Occupational Safety and Health (NIOSH) as exposure to airborne contaminants that is "likely to cause death or immediate or delayed permanent adverse health effects or prevent escape from such an environment." Examples include smoke or other poisonous gases at sufficiently high concentrations. It is calculated using the LD50 or LC50. The Occupational Safety and Health Administration (OSHA) regulation defines the term as "an atmosphere that poses an immediate threat to life, would cause irreversible adverse health effects, or would impair an individual's ability to escape from a dangerous atmosphere."
Personal protective equipment for IDLH conditions: pressure-demand supplied-air respirator equipped with a full facepiece in combination with an auxiliary pressure-demand self-contained breathing apparatus
Personal protective equipment for IDLH conditions: pressure-demand self-contained breathing apparatus with a full facepiece