What is the correct method for checking the seal of an SCBA facepiece?

The correct method for checking the seal of an SCBA facepiece is performing a negative pressure test. This procedure allows the user to ensure that the facepiece is properly sealed against the skin. By covering the exhalation valve and inhaling gently, the pressure inside the facepiece decreases, creating a vacuum effect. If the mask is properly sealed, it will adhere snugly to the face and should remain in place without any air leaks. This effective method highlights the importance of achieving a secure fit to guarantee the respiratory protection that SCBA provides, ensuring the wearer does not inhale any harmful agents.

While other methods might be used informally to assess the fit of an SCBA mask, they do not provide the same reliable confirmation of seal integrity. For instance, inhaling while covering the mask is not an official testing technique and can lead to inaccuracies due to improper technique or user error. Soaking the mask in water is not appropriate as it does not realistically test the fit or seal and may even damage the mask depending on its materials. Additionally, exhaling forcefully without a seal contradicts the purpose of a proper fit, as it creates a scenario where the mask is not maintained against the face.

In summary, the negative pressure test is a standardized