Why should users avoid talking while wearing SCBA?

Avoiding talking while wearing a Self-Contained Breathing Apparatus (SCBA) is primarily important because it can lead to wasted air and affect the fit of the facepiece. Speaking requires movement of the jaw and mouth, which can disturb the seal of the SCBA facepiece. A proper seal is crucial for maintaining the integrity of the breathing apparatus, ensuring that users receive clean, breathable air without any contaminants leaking in. When air is wasted through excessive talking, it can deplete the air supply more quickly than anticipated, which can become critical in emergency situations where maintaining air supply is essential.

Considering the other options, while talking can lead to potential risks such as shifting the facepiece or complicating communication signals, the direct impact on air consumption and fit makes avoiding conversation during use particularly significant. Consequently, the integrity and functionality of the SCBA are vital, especially in life-threatening scenarios.