NIOSH air filtration rating

The NIOSH air filtration rating is the U.S. National Institute for Occupational Safety and Health (NIOSH)'s classification of filtering respirators. The ratings describe the ability of the device to protect the wearer from solid and liquid particulates in the air. The certification and approval process for respiratory protective devices is governed by Part 84 of Title 42 of the Code of Federal Regulations (42 CFR 84). Respiratory protective devices so classified include air-purifying respirators (APR) such as filtering facepiece respirators and chemical protective cartridges that have incorporated particulate filter elements.

The NIOSH-provided classifications only cover the filtration of particles or aerosols, not the air-purifying respirator's ability to remove chemical gasses and vapors from air, which is regulated under 42 CFR 84 Subpart L. For chemical cartridge classifications, NIOSH, under 42 CFR 84, partially defers to American National Standard ANSI K13.1-1973. All classifications assume that the respirator is properly fitted.

NIOSH ratings trademark

It is illegal in the United States to use filtration terms coined under 42 CFR 84, or mark masks with the word "NIOSH" without the approval of NIOSH. Information about approved respirators can be found in the NIOSH certified equipment list (CEL).

Early NIOSH/USBM classifications

30 CFR 14 Schedule 21

30 CFR 11

Prior to the approval of 42 CFR 84, MSHA and NIOSH approved respirators under 30 CFR 11. Non-powered respirator filters were classified based on their design against a contaminant, including substances like Dusts, Fumes, Mists, radionuclides, and asbestos. Dust/Mist was usually tested with silica, and Fume was usually tested with lead fume.