Self-contained breathing apparatus (SCBA) fall into two categories: open circuit and closed circuit. Generally, SCBA is for situations where rescue workers, such as firefighters, need breathable air in Imminent Danger to Life and Health (IDLH) areas. Unlike PAPR systems, a self-contained breathing apparatus unit does not supply air from the immediate surroundings. The unit has a high-pressure tank supplying the air to the user.
SCBA Unit Parts
Also referred to as industrial breathing sets, SCBA units generally consist of:
- High-pressure air tank of 2,200 to 4,500 psi
These units protect the wearer from toxic fumes, spray, or contamination.
Open Circuit SCBA Systems
Open circuit industrial breathing sets provide air via a high-pressure tank and exhaust exhaled air to the atmosphere once used. It utilizes a regulator, often with two stages: one at the tank and one at the mask. These systems are generally full-face and provide the wearer with superior visibility. It is important to note that different people in different physical conditions can dramatically have an impact on usable airtime. Generally, larger or less fit individuals will use more air.
Closed Circuit SCBA Systems
Closed circuit SCBA involve complex systems that recirculate and recycle exhaled gas. It is generally used for longer periods, such as mine rescue situations where the confines of the space involved are a consideration.