The U.S. Food and Drug Administration (FDA) only clears N95 respirators certified by the National Institute for Occupational Safety and Health (NIOSH).
The FDA confirms that the respirator has a valid NIOSH certification number and therefore has met the particle filtration efficiency standards and other requirements.
Then the agency looks at whether the product also meets the biocompatibility, flammability, and fluid resistance standards and, if so, the product could be approved as a surgical N95 respirator.
If the surgical N95 respirator is proposed to have an antimicrobial additive, the FDA imposes additional requirements because of the concern that chemically attaching or embedding an antimicrobial could affect a filter’s barrier performance.
NIOSH does not issue a certification of a surgical N95 respirator, until the FDA confirms it is also reviewing the product.
Fluid resistance is one of the elements that is assessed in FDA’s Premarket Notification 510(k) approval process for surgical N95 respirators.
Testing of respirators to meet the FDA criteria for fluid resistance is usually done using the ASTM F1862 test method standard, which assesses whether the synthetic blood penetrates into the layers of the respirator. The test involves dispensing synthetic blood using a pressurized cannula for a distance of 12 inches through a small hole in a target plate to which the respirator is attached. A visual inspection of the inside of the respirator for fluid penetration is then conducted.
The agency also recognizes ASTM F2100 as the consensus standard for performance specifications of the materials used in respirators and medical face masks.