How should you adjust the SCBA facepiece for an airtight fit?

To achieve an airtight fit of the SCBA facepiece, it is critical to ensure that the seal is snug but not uncomfortable. A proper fit is essential for the facepiece to function optimally, as any gaps can allow contaminated air to enter, compromising the safety provided by the breathing apparatus.

A snug fit indicates that the facepiece is correctly sealing against the face, preventing any inhalation of unsafe air. However, it should not be uncomfortably tight, as this can cause pain or distraction and may lead to ineffective usage if a user feels pressured to remove it. Therefore, the adjustment must balance snugness with comfort to ensure both safety and operability during use.

The other methods described do not provide the correct approach: having loose straps can create gaps for air leakage, uneven adjustments can compromise the seal on one side, and fitting without adjustments likely results in an improper fit, thus failing to provide adequate protection.