Which type of respirator is known for using a supplied air source?

The supplied-air respirator (SAR) is specifically designed to draw air from an external source, providing a continuous supply of clean air to the user. This is particularly beneficial in environments where the air may be contaminated, as it allows the wearer to breathe safely while exposed to hazardous conditions. SARs are commonly used in situations where the air quality is poor or when working in confined spaces, making them essential for certain industrial applications.

In comparison to other options, a self-contained breathing apparatus (SCBA) also supplies air but does so from a tank carried by the user, making it mobile but dependent on the air supply in the tank. Negative pressure respirators rely on filtering air from the surrounding environment and are not suitable in highly contaminated areas. Dust masks do not supply air but rather filter out larger particles from the air that the wearer breathes, which may not be sufficient for many hazardous scenarios. Thus, the supplied-air respirator stands out as the type that uses an external air supply for enhanced safety and effectiveness in protecting users from air contaminants.