NIOSH 7402 – Product & Materials Guide

Asbestos Fiber Identification and Quantification by Transmission Electron Microscopy

NIOSH 7402 uses transmission electron microscopy (TEM) to qualify and quantify asbestos fibers found in the air. This technique provides complimentary results to fiber counts determined by NIOSH 7400, and provides more accurate asbestos fiber counts as non-asbestos particles are eliminated using this method. Samples are collected using a 25 mm air monitoring cassette equipped with a 50 mm electrically-conductive cowl and a MCE membrane filter. After collection, samples are processed to collapse the filter, creating a non-grainy background for easier fiber counting and identification by transmission electron microscopy. Fibers with a diameter <0.25 µm will not be detected by this method. Our product portfolio contains all the Millipore® filtration products you need for particle monitoring, regardless of your method or application.

Analytical Method: Transmission electron microscopy (TEM)

Learn more about the NIOSH 7402 method

Materials needed for NIOSH 7402

  • 25 mm MCE membrane with pore size between 0.45 - 1.2 µm
  • 25 mm cassette with 50 mm conductive cowl
  • Forceps to handle filter membrane

Products for NIOSH 7402

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