When is a fit test for a respirator necessary?

A fit test for a respirator is necessary before service in hazardous environments to ensure that the respirator forms an adequate seal against the user's face, providing the needed protection from airborne contaminants. This test assesses the effectiveness of the respirator's fit on the individual, which is crucial because a poor fit may allow hazardous substances to enter the respirator, negating its protective function.

The need for a fit test is based on the understanding that different individuals have unique facial structures that may affect how well a respirator fits. Conducting the fit test prior to entering a hazardous environment helps identify any issues with the fit that could compromise safety, ensuring that the respiration protection is effective.

In contrast, testing only after a month of use, when changing filters, or whenever the user feels uncomfortable does not guarantee that the respirator is adequately fitted for the hazards present. Regular fit testing should be part of an overall respiratory protection program to maintain safety standards.