What is a respirator fit test and why is it performed?

Respirators protect the wearer from inhaling chemicals and toxic materials. Without them, these hazards could have a devastating impact on the pulmonary and general health of workers.

Simply wearing a mask, however, is not enough to ensure adequate protection. The mask also needs to fit tightly but comfortably on the wearer's face. To protect the wearer, the respirator needs to form a seal around the face to prevent the penetration of hazardous substances. If this seal is compromised, fumes, vapors, and particulate matter can seep in, leading to exposure.

Users can sometimes feel that the respirator has been loosened and that the seal is broken, but judging the fit by feel alone is unreliable. For that reason, qualitative or quantitative fit tests should be performed at least once a year to ensure that the respirator continues to provide optimal protection.

A fit test should also be performed any time an employee undergoes a change that could affect how well the respirator fits on them. Gaining or losing a significant amount of weight, for instance, could affect the respirator's ability to create a protective seal. Growing or shaving off facial hair could also compromise the respirator's fit, and dental major dental work could affect the facial structure enough to make a difference as well.

No special requirements are needed to administer a respirator fit test – OSHA does not specify any training or certification.