Atmosphere-supplying Respirators

Atmosphere-supplying respirators supply clean air di­rectly to the user from a tank or compressor. An atmosphere­-supplying respirator has positive pressure, because air is delivered to the breather. The tank may be stationary with an air hose to the respirator (supplied-air respirator), or portable and worn on the user’s back, called a self-contained breathing apparatus or SCBA. SCBA respirators are appro­priate for areas considered immediately dangerous to life or health (IDLH). They are used when there is very little oxygen, such as in fire-fighting or in high concentrations of a very toxic pesticide in an enclosed area, such as during a fumigation.

Atmosphere-supplying Respirators.
Illustration by Donald Barry, University of Maine.