Atmosphere-supplying respirators (ASRs) provide clean breathing air from a separate source and protect users from a variety of airborne contaminants, including particles, gases, and vapors. ASRs can be used in oxygen-deficient environments in the form of pressure-demand with an emergency escape breathing apparatus (EEBA), supplied-air respirator (SAR), or self-contained breathing apparatus (SCBA).

Emergency Escape Breathing Apparatus (EEBA) provide 5-, 10-, or 15-minutes of air to allow the user to escape from environments where breathable air may suddenly change to hazardous air. EEBA are assigned to individual users or placed in strategic worksite locations for quick access.

SARs provide safe breathable air from a cylinder or compressor in low-oxygen environments or where air quality is compromised. Wearers are connected to an air source outside the immediate work area and their mobility is limited to the length of the airline. Air filtration products, such as air purification panels, manifolds, and filters, help ensure Grade D breathable air is available through SAR systems.

 SCBA are respiratory devices that contain and deliver breathable compressed air via a pressurized 30-, 45-, 60-, or 75-minute cylinder. The open-circuit, positive pressure-demand SCBA is the most common and used by firefighters and others who may be exposed to oxygen-deficient environments, smoke, toxic gases, or other contaminants that are immediately dangerous to life and health (IDLH).

ASRs require approval by the National Institute for Occupational Safety and Health (NIOSH) Respirator Approval Program and should be used in the context of a complete respiratory protection program per the Occupational Safety and Health Administration (OSHA) regulation 29 CFR 1910.134. This includes annual fit testing for all respirators with a tight-fitting facepiece. Regulatory compliance details are available at the individual product level.