What type of respirator provides clean breathing air from an external source?

The type of respirator that provides clean breathing air from an external source is the atmosphere-supplying respirator. This category includes devices specifically designed to deliver breathable air to the user, drawing from a separate, uncontaminated supply. These respirators are essential in environments where the air is not safe to breathe, such as in industrial or emergency situations involving hazardous materials.

Atmosphere-supplying respirators can include various configurations, such as supplied-air respirators (SARs), which typically use a hose connected to a clean air source, allowing the wearer to breathe in fresh air from a supply tank or a location free of contaminants. This makes them particularly versatile and crucial for safety in various applications where the quality of ambient air cannot be guaranteed.

Other respirator types, such as air-purifying respirators, rely on filters or cartridges to remove contaminants from the air the user is breathing, rather than supplying clean air directly. The self-contained breathing apparatus provides its own clean air from a tank carried by the user but does not draw from an external source. Mechanical respirators are generally used in medical settings to assist or control breathing rather than providing external air.