What type of pressure test should be performed when using a respirator?

When using a respirator, performing a positive pressure test is essential to ensure that the respirator forms a proper seal on the user's face and is functioning correctly. In a positive pressure test, the user exhales gently into the respirator while blocking the exhalation valve or any other openings. If the respirator remains inflated and there is no air leakage from the edges, it indicates that the respirator is sealing well against the face, providing adequate protection.

This is particularly important for respirators that rely on a tight fit to protect against airborne contaminants, such as asbestos fibers. A proper seal is crucial to prevent exposure to harmful substances, making the positive pressure test a vital component of respirator fit testing and safety procedures.

The other types of pressure tests, while important in different contexts, do not serve the same purpose for respirator use. Negative pressure tests, for example, involve inhaling to check for leaks, but they do not confirm whether the respirator can maintain a proper seal under exhalation.