What characterizes a positive pressure check during a fit test?

A positive pressure check during a fit test is characterized by the user breathing out and exerting positive pressure within the respirator. This process is crucial for ensuring that the respirator maintains an adequate seal against the face, thus preventing any air contaminants from entering the breathing space. During this test, if the respirator is properly fitted, the pressure will be maintained, and no outside air should be able to leak into the mask.

This method is particularly important as it helps in assessing the effectiveness of the respiratory protective device in providing a safe barrier against airborne hazards. The ability to exert positive pressure indicates not only a proper fit but also reassures the user that the equipment is functioning correctly before they are exposed to a potentially hazardous environment.