This analysis is used primarily for estimating asbestos concentrations in air. It is used to show compliance with limits set by NIOSH, OSHA, and other regulatory acencies. Fibers less than 0.25 microns in diameter will not be detected with this method.
The method can also be used to estimate the airborne concentration of other, non-asbestos materials as well, such as fibrous glass.
The NIOSH 7400 method is often used in conjuntion with electron microscopy methods such as the NIOSH 7402 method to aid in fiber identification.