What is the Assigned Protection Factor (APF)?
The APF is the level of protection that a particular type of respirator is expected to provide 95% of the time it is used. An APF of 10 means that a properly fitted respirator can be safely used in an atmosphere that has a concentration of up to 10 times the PEL (Permissible Exposure Limit) for the particular hazardous agent. APF values are assigned by national (U.S.A.) standards organizations such as NIOSH and ANSI. It is customary practice to use ten times the APF as the FF Pass Level when doing quantitative fit testing. The innovative Fitseal™ adhesion respirators exceed the minimum Pass Level requirements.
