What specific rating does a NIOSH-approved HEPA filter carry?

A NIOSH-approved HEPA filter is classified with a P100 rating, which indicates that it is capable of filtering at least 99.97% of airborne particles that are 0.3 micrometers in diameter. This level of filtration is essential in environments where exposure to hazardous materials, such as asbestos, is a concern. The designation 'P' indicates that the filter is resistant to oil and can be used in environments where oil aerosols are present, enhancing its utility in various industrial settings.

The P100 rating ensures maximum protection for workers by significantly reducing their exposure to harmful particulates. In contrast, the other ratings such as P95, P90, and P80 have lower filtration efficiencies and do not meet the stringent requirements set for environments with high asbestos exposure risk. Therefore, the P100 rating represents the highest level of protection provided by a HEPA filter endorsed by NIOSH.