When using positive pressure self-contained breathing apparatus. a poor seal between the facepiece and the firefighter's face is:

• A. Not dangerous, because the positive pressure will keep gasses out of the facepiece
• B. Dangerous, because it is depleting the air supply more quickly
• C. Not possible, because the positive pressure will seal the facepiece to face
• D. The main cause of death on the fire ground

Answer: (B)

Understanding how a positive-pressure SCBA works helps explain why a poor facepiece seal is dangerous. The system pushes air into the facepiece to create a slight overpressure, which helps keep outside contaminants from entering. If the seal around the face is not tight, air leaks out around the edges instead of staying inside. The regulator must keep delivering air to maintain that overpressure, so leaks cause the air supply to be used up more quickly. That reduced air time increases risk on the fireground. While a positive pressure helps, it doesn’t guarantee a perfect seal, and a poor seal can still let contaminants in and shorten the duration you can safely work.