This exploratory set of experiments investigated the impact of external exposure temperatures on Self Contained Breathing Apparatus (SCBA) supply air, and the potential for the supply air to be heated when it is subjected to an elevated temperature environment during firefighting operations. For these tests, an entire SCBA assembly was placed inside an elevated temperature flow loop. The SCBA facepiece was fitted onto a mannequin headform, and a computer controlled breathing simulator provided artificial breathing. The SCBA was exposed to airflows with temperatures ranging between 100 ºC and 200 ºC for time durations up to 1200 s (20 min). The temperature of the air from the SCBA was measured in the location of the mannequins mouth. The results of these experiments demonstrate that the supply air temperature does increase when the SCBA is exposed to external conditions of elevated temperatures. The increase in temperature of the supply air was greater for the tests at the higher external temperatures, and the supply air temperature increased as the duration of exposure to the elevated external temperature increased. Depending on the exposure time and temperature, it may be possible to for uncomfortable or even dangerous breathing air temperatures to occur.
Citation: Technical Note (NIST TN) - 1809
NIST Pub Series: Technical Note (NIST TN)
Pub Type: NIST Pubs
Self Contained Breathing Apparatus, SCBA, firefighting operations